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Sample records for analytical techniques based

  1. 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.

  2. Analytical Method for Selecting a Rectification Technique for a Piezoelectric Generator based on Admittance Measurement

    NASA Astrophysics Data System (ADS)

    Mateu, Loreto; Zessin, Henrik; Spies, Peter

    2013-12-01

    AC-DC converters employed for harvesting power from piezoelectric transducers can be divided into linear (i.e. diode bridge) and non-linear (i.e. synchronized switch harvesting on inductor, SSHI). This paper presents an analytical technique based on the measurement of the impedance circle of the piezoelectric element to determine whether either diode bridge or SSHI converter harvests more of the available power at the piezoelectric element.

  3. Nuclear analytical techniques in medicine

    SciTech Connect

    Cesareo, R.

    1988-01-01

    This book acquaints one with the fundamental principles and the instrumentation relevant to analytical technique based on atomic and nuclear physics, as well as present and future biomedical applications. Besides providing a theoretical description of the physical phenomena, a large part of the book is devoted to applications in the medical and biological field, particularly in hematology, forensic medicine and environmental science. This volume reviews methods such as the possibility of carrying out rapid multi-element analysis of trace elements on biomedical samples, in vitro and in vivo, by XRF-analysis; the ability of the PIXE-microprobe to analyze in detail and to map trace elements in fragments of biomedical samples or inside the cells; the potentiality of in vivo nuclear activation analysis for diagnostic purposes. Finally, techniques are described such as radiation scattering (elastic and inelastic scattering) and attenuation measurements which will undoubtedly see great development in the immediate future.

  4. 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.

  5. 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

    2012-01-01

    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. PMID:22089026

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Advances in analytical spectrochemistry with ionized gases. I. Improved fundamental understanding through laser based techniques. II. Novel bioanalytical applications

    NASA Astrophysics Data System (ADS)

    Gamez, Gerardo

    Over the past several decades plasma spectrochemistry has become the workhorse for performing elemental analysis. Nevertheless, we are still far from fully understanding the fundamental mechanisms that affect and led to the production of the analytical signal. Thus, the first part of this study was focused on improving our knowledge of plasma fundamental processes. First, the effect of exposing an inductively coupled plasma to a mass spectrometer sampling interface was investigated. Our results show that the mass spectrometer sampler affects the plasma fundamental parameters in a way that changes with gas flow, forward r.f. power, and plasma torch-to-sampler distance. The findings help to better explain the plasma sampling process and have made clear that results from mass-spectrometry based plasma diagnostics are applicable to unperturbed plasmas only as a rough approximation. Second, and instrument was constructed to characterize the fundamental parameters of an analytical glow discharge by using Thomson and Rayleigh laser scattering. A continuous dc glow discharge source was studied and a set of corresponding numerical modeling experiments were performed. The resulting theory agrees qualitatively with the experimental findings; moreover, the theoretical and experimental techniques often provide complementary information. Finally, a temporally and spatially resolved map of the fundamental parameters of a dc glow discharge operated in pulsed mode was obtained. The results confirm previously proposed electron energy-transfer mechanisms at the beginning of the pulse. In contrast, the findings call into question other mechanisms involving plasma gas metastable formation proposed for the time period immediately after the end of the pulse. In the second part of the study an imaging radio frequency glow discharge instrument was developed to provide three-dimensional elemental analysis of solids. The newly developed instrument was then applied to the simultaneous

  11. Thermal Measurement Techniques in Analytical Microfluidic Devices.

    PubMed

    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

  12. Determination of PASHs by various analytical techniques based on gas chromatography-mass spectrometry: application to a biodesulfurization process.

    PubMed

    Mezcua, Milagros; Fernández-Alba, Amadeo R; Boltes, Karina; Alonso Del Aguila, Raul; Leton, Pedro; Rodríguez, Antonio; García-Calvo, Eloy

    2008-06-15

    Polycyclic aromatic sulphur heterocyclic (PASH) compounds, such as dibenzothiophene (DBT) and alkylated derivatives are used as model compounds in biodesulfurization processes. The development of these processes is focused on the reduction of the concentration of sulphur in gasoline and gas-oil [D.J. Monticello, Curr. Opin. Biotechnol. 11 (2000) 540], in order to meet European Union and United States directives. The evaluation of biodesulfurization processes requires the development of adequate analytical techniques, allowing the identification of any transformation products generated. The identification of intermediates and final products permits the evaluation of the degradation process. In this work, seven sulfurated compounds and one non-sulfurated compound have been selected to develop an extraction method and to compare the sensitivity and identification capabilities of three different gas chromatography ionization modes. The selected compounds are: dibenzothiophene (DBT), 4-methyl-dibenzothiophene (4-m-DBT), 4,6-dimethyl-dibenzothiophene (4,6-dm-DBT) and 4,6 diethyl-dibenzothiophene (4,6 de-DBT), all of which can be used as model compounds in biodesulfurization processes; as well as dibenzothiophene sulfoxide (DBTO(2)), dibenzothiophene sulfone (DBTO) and 2-(2-hydroxybiphenyl)-benzenesulfinate (HBPS), which are intermediate products in biodesulfurization processes of DBT [ A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa, Biochem. Eng. J. 26 (2005) 168]. Furthermore, a non-sulfurated compound, 2-hydroxybiphenyl (2-HBP), has also been selected as it is the final product in the biodesulfurization process of DBT [A. Alcon, V.E. Santos, A.B. Martín, P. Yustos, F. García-Ochoa. Biochem. Eng. J. 26 (2005) 168]. Since, typically, biodesulfurization reactions take place in a biphasic medium, two extraction methods have been developed: a liquid-liquid extraction method for the watery phase and a solid phase extraction method for the organic phase

  13. 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. PMID:24054247

  14. 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.

  15. Nuclear material investigations by advanced analytical techniques

    NASA Astrophysics Data System (ADS)

    Degueldre, C.; Kuri, G.; Martin, M.; Froideval, A.; Cammelli, S.; Orlov, A.; Bertsch, J.; Pouchon, M. A.

    2010-10-01

    Advanced analytical techniques have been used to characterize nuclear materials at the Paul Scherrer Institute during the last decade. The analysed materials ranged from reactor pressure vessel (RPV) steels, Zircaloy claddings to fuel samples. The processes studied included copper cluster build up in RPV steels, corrosion, mechanical and irradiation damage behaviour of PWR and BWR cladding materials as well as fuel defect development. The used advanced techniques included muon spin resonance spectroscopy for zirconium alloy defect characterization while fuel element materials were analysed by techniques derived from neutron and X-ray scattering and absorption spectroscopy.

  16. 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

  17. 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.

  18. 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.

  19. 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. PMID:25597689

  20. The application of advanced analytical techniques to direct coal liquefaction

    SciTech Connect

    Brandes, S.D.; Winschel, R.A.; Burke, F.P.; Robbins, G.A.

    1991-12-31

    Consol is coordinating a program designed to bridge the gap between the advanced, modern techniques of the analytical chemist and the application of those techniques by the direct coal liquefaction process developer, and to advance our knowledge of the process chemistry of direct coal liquefaction. The program is designed to provide well-documented samples to researchers who are utilizing techniques potentially useful for the analysis of coal derived samples. The choice of samples and techniques was based on an extensive survey made by Consol of the present status of analytical methodology associated with direct coal liquefaction technology. Sources of information included process developers and analytical chemists. Identified in the survey are a number of broadly characterizable needs. These categories include a need for: A better understanding of the nature of the high molecular weight, non-distillable residual materials (both soluble and insoluble) in the process streams; improved techniques for molecular characterization, heteroatom and hydrogen speciation and a knowledge of the hydrocarbon structural changes across coal liquefaction systems; better methods for sample separation; application of advanced data analysis methods; the use of more advanced predictive models; on-line analytical techniques; and better methods for catalyst monitoring.

  1. 40 CFR 141.27 - Alternate analytical techniques.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 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...

  2. 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)

  3. Characterizing nonconstant instrumental variance in emerging miniaturized analytical techniques.

    PubMed

    Noblitt, Scott D; Berg, Kathleen E; Cate, David M; Henry, Charles S

    2016-04-01

    Measurement variance is a crucial aspect of quantitative chemical analysis. Variance directly affects important analytical figures of merit, including detection limit, quantitation limit, and confidence intervals. Most reported analyses for emerging analytical techniques implicitly assume constant variance (homoskedasticity) by using unweighted regression calibrations. Despite the assumption of constant variance, it is known that most instruments exhibit heteroskedasticity, where variance changes with signal intensity. Ignoring nonconstant variance results in suboptimal calibrations, invalid uncertainty estimates, and incorrect detection limits. Three techniques where homoskedasticity is often assumed were covered in this work to evaluate if heteroskedasticity had a significant quantitative impact-naked-eye, distance-based detection using paper-based analytical devices (PADs), cathodic stripping voltammetry (CSV) with disposable carbon-ink electrode devices, and microchip electrophoresis (MCE) with conductivity detection. Despite these techniques representing a wide range of chemistries and precision, heteroskedastic behavior was confirmed for each. The general variance forms were analyzed, and recommendations for accounting for nonconstant variance discussed. Monte Carlo simulations of instrument responses were performed to quantify the benefits of weighted regression, and the sensitivity to uncertainty in the variance function was tested. Results show that heteroskedasticity should be considered during development of new techniques; even moderate uncertainty (30%) in the variance function still results in weighted regression outperforming unweighted regressions. We recommend utilizing the power model of variance because it is easy to apply, requires little additional experimentation, and produces higher-precision results and more reliable uncertainty estimates than assuming homoskedasticity. PMID:26995641

  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. Analytical techniques for direct identification of biosignatures and microorganisms

    NASA Astrophysics Data System (ADS)

    Cid, C.; Garcia-Descalzo, L.; Garcia-Lopez, E.; Postigo, M.; Alcazar, A.; Baquero, F.

    2012-09-01

    Rover missions to potentially habitable ecosystems require portable instruments that use minimal power, require no sample preparation, and provide suitably diagnostic information to an Earth-based exploration team. In exploration of terrestrial analogue environments of potentially habitable ecosystems it is important to screen rapidly for the presence of biosignatures and microorganisms and especially to identify them accurately. In this study, several analytical techniques for the direct identification of biosignatures and microorganisms in different Earth analogues of habitable ecosystems are compared.

  6. 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.

  7. 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.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    Frontasyeva, Marina

    2010-01-01

    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.

  10. 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.

  11. The sensitivity of the PIGE analytical technique

    NASA Astrophysics Data System (ADS)

    Mateus, R.; Jesus, A. P.; Fonseca, M.; Luís, H.; Ribeiro, J. P.

    2007-11-01

    The aim of this work is to provide a basis for the estimation of fluorine and lithium contributions to the background of gamma-ray spectra and of their influence on PIGE (Proton-Induced Gamma-Ray Emission) detection limits of lithium, boron, fluorine and sodium. Results for yields and background contributions of lithium and fluorine were obtained from measurements using samples of known composition. Detection limits were determined by extrapolation of those measurements and by calculations based on the inferred background values. Yields were converted in concentrations using the ERYA (Emitted Radiation Yield Analysis) code. This code divides the sample in sublayers parallel to its surface for the integration of the partial gamma-ray yields along the depth of the target.

  12. 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.

  13. 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

    2007-02-01

    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

  14. 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. PMID:24892529

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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. PMID:22265377

  2. 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.

  3. 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

  4. Micro-extraction techniques in analytical toxicology: short review.

    PubMed

    Flanagan, R J; Morgan, P E; Spencer, E P; Whelpton, R

    2006-01-01

    This paper discusses new developments in plasma micro-extraction techniques in the context of established micro-extraction and protein precipitation methodology. Simple liquid-liquid solvent extraction (LLE) of plasma with direct GC or HPLC analysis of the resulting extract has been used for many years. Butyl acetate and methyl t-butyl ether (MTBE) give efficient extraction of many drugs and metabolites from small volumes of plasma or whole blood at an appropriate pH, and form the upper layer, thus simplifying extract removal. Butyl acetate does not interfere with NPD, ECD or MS in GC, whilst MTBE has a relatively low UV cutoff (220 nm). Thus, HPLC eluents that use a high proportion of an organic component allow MTBE extracts to be analysed directly. 'Salting-out' and extractive derivatization using acetic anhydride or phenylboronic acid can be used with appropriate analytes. As regards protein precipitation, an important consideration is lowering the pH, although this is not feasible with acid-labile analytes. More recent developments include sold-phase micro-extraction (SPME) and liquid-phase micro-extraction (LPME). This latter technique especially may prove invaluable as analytes that cannot easily be extracted with LLE can be isolated simply at low cost with a minimum of apparatus. PMID:16779788

  5. 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. PMID:15270709

  6. 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.

  7. 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. PMID:24238710

  8. 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. PMID:25864956

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Comparison of the Glass and Hunter-Schmidt Meta-Analytic Techniques.

    ERIC Educational Resources Information Center

    Hough, Susan L.; Hall, Bruce W.

    1994-01-01

    Compares results of Hunter-Schmidt meta-analytic technique with results of Glass meta-analytic technique on three meta-analytic data sets chosen from the literature, hypothesizing that the Hunter-Schmidt mean effect size would be significantly larger than the Glass mean effect size because of correlation for measurement error. Results confirmed…

  16. 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.

  17. Comparison of several NASTRAN analytical techniques for large structures

    NASA Technical Reports Server (NTRS)

    Zemer, D. T.

    1978-01-01

    In order to plan for the finite element structural analysis of future aircraft, five static analysis techniques using the MacNeal-Schwendler Corporation version of NASTRAN were evaluated. The structure was analyzed as: (1) a single model with a symmetric loading condition; (2) a single model with symmetric/nonsymmetric loading conditions; (3) three substructures in three phases using tape storage with a symmetric loading condition; (4) three superelements using data base storage with a symmetric loading condition; and (5) three superelements using data base storage with cyclic symmetry for symmetric/nonsymmetric loading conditions. The superelement techniques proved superior to the single model approaches by reducing computer time for redesign work by as much as 70 percent.

  18. 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…

  19. Comparative study of analytical techniques for determining protein charge.

    PubMed

    Filoti, Dana I; Shire, Steven J; Yadav, Sandeep; Laue, Thomas M

    2015-07-01

    As interest in high-concentration protein formulations has increased, it has become apparent that routine, accurate protein charge measurements are necessary. There are several techniques for charge measurement, and a comparison of the methods is needed. The electrophoretic mobility, effective charge, and Debye-Hückel-Henry charge have been determined for bovine serum albumin, and human serum albumin. Three different electrophoretic methods were used to measure the electrophoretic mobility: capillary electrophoresis, electrophoretic light scattering, and membrane confined electrophoresis. In addition, the effective charge was measured directly using steady-state electrophoresis. Measurements made at different NaCl concentrations, pH, and temperatures allow comparison with previous charge estimates based on electrophoresis, Donnan equilibrium, and pH titration. Similar charge estimates are obtained by all of the methods. The strengths and limitations of each technique are discussed, as are some general considerations about protein charge and charge determination. PMID:25911989

  20. 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

  1. 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

  2. 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)

  3. 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.

  4. Development of analytical orbit propagation technique with drag

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Two orbit computation methods were used: (1) numerical method- The solution to the satellite differential equations were solved in a step-by-step manner, using a mathematical algorithm taken from numerical analysis; and (2) analytical method - The solution was expressed by explicit functions of the independent variable. Analytical drag modules, tesseral terms initialization module, second order and long period terms module, and verification testing of the ASOP program were also considered.

  5. Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies

    NASA Astrophysics Data System (ADS)

    Nečemer, Marijan; Kump, Peter; Ščančar, Janez; Jaćimović, Radojko; Simčič, Jurij; Pelicon, Primož; Budnar, Miloš; Jeran, Zvonka; Pongrac, Paula; Regvar, Marjana; Vogel-Mikuš, Katarina

    2008-11-01

    Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry—EDXRF, total reflection X-ray fluorescence spectrometry—TXRF and micro-proton induced X-ray emission—micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast

  6. 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…

  7. Effect of shunted piezoelectric control for tuning piezoelectric power harvesting system responses—analytical techniques

    NASA Astrophysics Data System (ADS)

    Lumentut, M. F.; Howard, I. M.

    2015-10-01

    This paper presents new analytical modelling of shunt circuit control responses for tuning electromechanical piezoelectric vibration power harvesting structures with proof mass offset. For this combination, the dynamic closed-form boundary value equations reduced from strong form variational principles were developed using the extended Hamiltonian principle to formulate the new coupled orthonormalized electromechanical power harvesting equations showing combinations of the mechanical system (dynamical behaviour of piezoelectric structure), electromechanical system (electrical piezoelectric response) and electrical system (tuning and harvesting circuits). The reduced equations can be further formulated to give the complete forms of new electromechanical multi-mode frequency response functions and the time waveform of the standard AC-DC circuit interface. The proposed technique can demonstrate self-adaptive harvesting response capabilities for tuning the frequency band and the power amplitude of the harvesting devices. The self-adaptive tuning strategies are demonstrated by modelling the shunt circuit behaviour of the piezoelectric control layer in order to optimize the harvesting piezoelectric layer during operation under input base excitation. In such situations, with proper tuning parameters the system performance can be substantially improved. Moreover, the validation of the closed-form technique is also provided by developing the Ritz method-based weak form analytical approach giving similar results. Finally, the parametric analytical studies have been explored to identify direct and relevant contributions for vibration power harvesting behaviours.

  8. 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.

  9. 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

  10. Intracavity Optogalvanic Spectroscopy, A New Ultra-sensitive Analytical Technique for 14C Analysis

    PubMed Central

    Murnick, Daniel E.; Dogru, Ozgur; Ilkmen, Erhan

    2009-01-01

    We show a new ultra-sensitive laser based analytical technique, intracavity optogalvanic spectroscopy, allowing extremely high sensitivity for detection of 14C labeled carbon dioxide. Capable of replacing large accelerator mass spectrometers, the technique quantifies attomoles of 14C in submicrogram samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity and detection via impedance variations, limits of detection near 10-15 14C:12C ratios are obtained. Using a 15W 14CO2 laser, a linear calibration with samples from 10-15 to >2 × 10-12 in 14C:12C ratios, as determined by accelerator mass spectrometry, is demonstrated. Possible applications include microdosing studies in drug development, individualized sub-therapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon. The method can also be applied to detection of other trace entities. PMID:18533685

  11. 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.

  12. Fabrication and Operation of Paper-Based Analytical Devices

    NASA Astrophysics Data System (ADS)

    Jiang, Xiao; Fan, Z. Hugh

    2016-06-01

    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.

  13. 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. PMID:27070184

  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. PMID:25074050

  15. 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.

  16. 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…

  17. 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.

  18. Nanoscale device modeling using a conserving analytic continuation technique

    NASA Astrophysics Data System (ADS)

    Mera, H.; Lannoo, M.; Cavassilas, N.; Bescond, M.

    2013-08-01

    We propose an alternative approach to self-consistency and conservation laws in the theory of nonequilibrium Green's functions (NEGF's), which provides an infinite family of conserving but, generally, non-self-consistent approximations. Within any Φ-derivable approximation the associated Born series for the NEGF is shown to be conserving. Expectation values calculated from the Born series are then used to build a Padé table of approximations, while conservation laws are naturally preserved. We implement this technique for the Φ-derivable self-consistent Born approximation (SCBA), for which we obtain a recursion relation that yields the Born series for the NEGF up to any desired order. The expectation values calculated from the Born series are then postprocessed to build a Padé table of conserving approximations. The calculation of the SCBA photocurrent in a biased molecular junction model provides an example where, in addition to conservation laws, a substantial convergence acceleration relative to standard techniques is achieved. The present reformulation of the SCBA might aid convergence to the fully self-consistent results in a wide variety of problems.

  19. A survey of probabilistic methods used in reliability, risk and uncertainty analysis: Analytical techniques 1

    SciTech Connect

    Robinson, D.G.

    1998-06-01

    This report provides an introduction to the various probabilistic methods developed roughly between 1956--1985 for performing reliability or probabilistic uncertainty analysis on complex systems. This exposition does not include the traditional reliability methods (e.g. parallel-series systems, etc.) that might be found in the many reliability texts and reference materials (e.g. and 1977). Rather, the report centers on the relatively new, and certainly less well known across the engineering community, analytical techniques. Discussion of the analytical methods has been broken into two reports. This particular report is limited to those methods developed between 1956--1985. While a bit dated, methods described in the later portions of this report still dominate the literature and provide a necessary technical foundation for more current research. A second report (Analytical Techniques 2) addresses methods developed since 1985. The flow of this report roughly follows the historical development of the various methods so each new technique builds on the discussion of strengths and weaknesses of previous techniques. To facilitate the understanding of the various methods discussed, a simple 2-dimensional problem is used throughout the report. The problem is used for discussion purposes only; conclusions regarding the applicability and efficiency of particular methods are based on secondary analyses and a number of years of experience by the author. This document should be considered a living document in the sense that as new methods or variations of existing methods are developed, the document and references will be updated to reflect the current state of the literature as much as possible. For those scientists and engineers already familiar with these methods, the discussion will at times become rather obvious. However, the goal of this effort is to provide a common basis for future discussions and, as such, will hopefully be useful to those more intimate with

  20. 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

  1. A task-based analytical framework for ultrasonic beamformer comparison.

    PubMed

    Nguyen, Nghia Q; Prager, Richard W; Insana, Michael F

    2016-08-01

    A task-based approach is employed to develop an analytical framework for ultrasound beamformer design and evaluation. In this approach, a Bayesian ideal-observer provides an idealized starting point and a way to measure information loss in practical beamformer designs. Different approximations of this ideal strategy are shown to lead to popular beamformers in the literature, including the matched filter, minimum variance (MV), and Wiener filter (WF) beamformers. Analysis of the approximations indicates that the WF beamformer should outperform the MV approach, especially in low echo signal-to-noise conditions. The beamformers are applied to five typical tasks from the BIRADS lexicon. Their performance is evaluated based on ability to discriminate idealized malignant and benign features. The numerical results show the advantages of the WF over the MV technique in general; although performance varies predictably in some contrast-limited tasks because of the model modifications required for the MV algorithm to avoid ill-conditioning. PMID:27586736

  2. Analytical techniques in biomedical stable isotope applications: (isotope ratio) mass spectrometry or infrared spectrometry?

    PubMed

    Stellaard, Frans; Elzinga, Henk

    2005-12-01

    An overview is presented of biomedical applications of stable isotopes in general, but mainly focused on the activities of the Center for Liver, Digestive and Metabolic Diseases of the University Medical Center Groningen. The aims of metabolic studies in the areas of glucose, fat, cholesterol and protein metabolism are briefly explained, as well as the principle of breath testing and the techniques to study body composition and energy expenditure. Much attention is paid to the analytical considerations based upon metabolite concentrations, sample size restrictions, the availability of stable isotope labelled substrates and dose requirements in relation to compound-specific isotope analysis. The instrumental advantages and limitations of the generally used techniques gas chromatography/reaction/isotope ratio mass spectrometry and gas chromatography/mass spectrometry are described as well as the novelties of the recently commercialised liquid chromatography/combustion/isotope ratio mass spectrometry. The present use and future perspective of infrared (IR) spectrometry for clinical and biomedical stable isotope applications are reviewed. In this respect, the analytical demands on IR spectrometry are discussed to enable replacement of isotope ratio mass spectrometry by IR spectrometry, in particular, for the purpose of compound-specific isotope ratio analysis in biological matrices. PMID:16543190

  3. 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.

  4. 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.

  5. 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. PMID:19282548

  6. 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. PMID:26608759

  7. 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.

  8. Laser analytical spectrometry based on optical phase conjugation by degenerate four-wave mixing in a flowing liquid analyte cell.

    PubMed

    Wu, Z Q; Tong, W G

    1989-05-01

    Nonlinear laser spectroscopy based on optical phase conjugation by degenerate four-wave mixing in an absorbing liquid analyte solution is reported as a sensitive analytical technique using a relatively low-power continuous-wave argon ion laser as the excitation source. This novel laser method provides excellent detection sensitivity since the analytical signal is a wavefront-reversed replica of the probe beam. Optical signal detection is convenient and efficient since the signal is a visible coherent laser beam. Important characteristics of this nonlinear laser method include cubic dependence of signal on laser power and quadratic dependence of signal on concentration. Excellent sensitivity, small detection volume, and convenient sample introduction offer many potential applications in trace-level condensed-phase analysis of continuously flowing systems. A preliminary detection limit of 2.9 X 10(-18) mol of eosin B in a simple flow cell is reported. PMID:2729603

  9. 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. PMID:16891073

  10. Novel computational and analytic techniques for nonlinear systems applied to structural and celestial mechanics

    NASA Astrophysics Data System (ADS)

    Elgohary, Tarek Adel Abdelsalam

    In this Dissertation, computational and analytic methods are presented to address nonlinear systems with applications in structural and celestial mechanics. Scalar Homotopy Methods (SHM) are first introduced for the solution of general systems of nonlinear algebraic equations. The methods are applied to the solution of postbuckling and limit load problems of solids and structures as exemplified by simple plane elastic frames, considering only geometrical nonlinearities. In many problems, instead of simply adopting a root solving method, it is useful to study the particular problem in more detail in order to establish an especially efficient and robust method. Such a problem arises in satellite geodesy coordinate transformation where a new highly efficient solution, providing global accuracy with a non-iterative sequence of calculations, is developed. Simulation results are presented to compare the solution accuracy and algorithm performance for applications spanning the LEO-to-GEO range of missions. Analytic methods are introduced to address problems in structural mechanics and astrodynamics. Analytic transfer functions are developed to address the frequency domain control problem of flexible rotating aerospace structures. The transfer functions are used to design a Lyapunov stable controller that drives the spacecraft to a target position while suppressing vibrations in the flexible appendages. In astrodynamics, a Taylor series based analytic continuation technique is developed to address the classical two-body problem. A key algorithmic innovation for the trajectory propagation is that the classical averaged approximation strategy is replaced with a rigorous series based solution for exactly computing the acceleration derivatives. Evidence is provided to demonstrate that high precision solutions are easily obtained with the analytic continuation approach. For general nonlinear initial value problems (IVPs), the method of Radial Basis Functions time domain

  11. 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…

  12. 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. PMID:26118962

  13. A Mur Type Analytical Absorbing Boundary Condition for Multidimensional Wave Analysis with the Directional Splitting Technique

    NASA Astrophysics Data System (ADS)

    Sasaki, Kensuke; Suzuki, Yukihisa

    A Mur type analytical absorbing boundary condition (A-ABC), which is based on the one-dimensional one-way wave equation, is proposed for multidimensional wave analysis by introducing the directional splitting technique. This new absorbing boundary condition is expansion of the first-order Mur. The absorbing ability, required memory, and calculation speed of the Mur type A-ABC are evaluated by comparison with those of conventional ABCs. The result indicated that absorbing ability of the proposed ABC is higher than the first-order Mur and lower than the second-order Mur at large incident angle. While, our proposed ABC has advantage in both required memory and calculation speed by comparison with the second-order Mur. Thus, effectivity of the proposed Mur type A-ABC is shown.

  14. 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. PMID:26952314

  15. Recovery of Magnesium from Seawaters and Development of Analytical Techniques for Eco-Friendly Materials Processing.

    NASA Astrophysics Data System (ADS)

    Yoon, H.; Yoon, C.; Chung, K.

    2008-12-01

    Nevertheless other resources such as fossil fuel, oils, mineral resources, drive continued interest in developing fundamental techniques for recovering valuable metals like seawater origin. A process for recovery of magnesium from brine and bittern have been described in achieving low-level detection limits as well as reliability of analytical technique. The choice of analytical technique to meet the most stringent analytical needs of our fields is ICP-OES and XRF for commercial purposes in high solid waters like bittern. This study contains the results of a study of processes for seawater reverse osmosis with enhanced precipitation yield such as NaCl, Mg(OH)2, and Br2. The original bittern composition supplied from Hanjoo Co. Ltd. was pretreated for microbial matter and additional NaOH, NH4OH, or Na2CO3. Adding NaOH at pH 9.0 to pH 9.9 yield precipitation of Na2CO3.

  16. Optical microscopy as a comparative analytical technique for single-particle dissolution studies.

    PubMed

    Svanbäck, Sami; Ehlers, Henrik; Yliruusi, Jouko

    2014-07-20

    Novel, simple and cost effective methods are needed to replace advanced chemical analytical techniques, in small-scale dissolution studies. Optical microscopy of individual particles could provide such a method. The aim of the present work was to investigate and verify the applicability of optical microscopy as an analytical technique for drug dissolution studies. The evaluation was performed by comparing image and chemical analysis data of individual dissolving particles. It was shown that the data obtained by image analysis and UV-spectrophotometry produced practically identical dissolution curves, with average similarity and difference factors above 82 and below 4, respectively. The relative standard deviation for image analysis data, of the studied particle size range, varied between 1.9% and 3.8%. Consequently, it is proposed that image analysis can be used, on its own, as a viable analytical technique in single-particle dissolution studies. The possibility for significant reductions in sample preparation, operational cost, time and substance consumption gives optical detection a clear advantage over chemical analytical methods. Thus, image analysis could be an ideal and universal analytical technique for rapid small-scale dissolution studies. PMID:24751345

  17. RBS: an analytical technique for elemental characterization of standards; advantages and limits of application

    NASA Astrophysics Data System (ADS)

    Climent-Font, A.; Fernández-Jiménez, M. T.; Wätjen, U.; Perrière, J.

    1994-12-01

    Rutherford backscattering spectrometry (RBS) is an ion beam analytical technique fulfilling unique conditions to give information on the elemental composition of the near surface of materials. Some of the physical processes involved in an RBS experiment are very well understood and are described by analytical formulas allowing for the elaboration of simple computer codes recreating theoretical RBS experiments. Such computer codes are of great help for fast and accurate interpretation of experimental RBS spectra. Under favorable circumstances quantitative composition depth profiles can be obtained. The possibility of doing absolute measurements with RBS makes it very attractive for the characterization of standard samples useful and necessary in other analytical techniques if quantitative analysis is required. In spite of its capabilities, RBS is not free from some flaws that make difficult to reduce the level of uncertainties below 5% in the quantification of the spectra or to make an unambiguous interpretation of the results. In this work we illustrate with a few examples some of the relevant features of RBS which make this analytical technique so useful, and we also discuss situations in which RBS can give only ambiguous information, and where the assistance of a complementary analytical technique is required for a successful interpretation of the results.

  18. 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. PMID:19064072

  19. 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.

  20. 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.

  1. Integration of datasets from different analytical techniques to assess the impact of nutrition on human metabolome

    PubMed Central

    Vernocchi, Pamela; Vannini, Lucia; Gottardi, Davide; Del Chierico, Federica; Serrazanetti, Diana I.; Ndagijimana, Maurice; Guerzoni, Maria E.

    2012-01-01

    Bacteria colonizing the human intestinal tract exhibit a high phylogenetic diversity that reflects their immense metabolic potentials. The catalytic activity of gut microbes has an important impact on gastrointestinal (GI) functions and host health. The microbial conversion of carbohydrates and other food components leads to the formation of a large number of compounds that affect the host metabolome and have beneficial or adverse effects on human health. Metabolomics is a metabolic-biology system approach focused on the metabolic responses understanding of living systems to physio-pathological stimuli by using multivariate statistical data on human body fluids obtained by different instrumental techniques. A metabolomic approach based on an analytical platform could be able to separate, detect, characterize and quantify a wide range of metabolites and its metabolic pathways. This approach has been recently applied to study the metabolic changes triggered in the gut microbiota by specific diet components and diet variations, specific diseases, probiotic and synbiotic food intake. This review describes the metabolomic data obtained by analyzing human fluids by using different techniques and particularly Gas Chromatography Mass Spectrometry Solid-phase Micro Extraction (GC-MS/SPME), Proton Nuclear Magnetic Resonance (1H-NMR) Spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopy. This instrumental approach has a good potential in the identification and detection of specific food intake and diseases biomarkers. PMID:23248777

  2. Analytical techniques for characterization of cyclodextrin complexes in the solid state: A review.

    PubMed

    Mura, Paola

    2015-09-10

    Cyclodextrins are cyclic oligosaccharides able to form inclusion complexes with a variety of hydrophobic guest molecules, positively modifying their physicochemical properties. A thorough analytical characterization of cyclodextrin complexes is of fundamental importance to provide an adequate support in selection of the most suitable cyclodextrin for each guest molecule, and also in view of possible future patenting and marketing of drug-cyclodextrin formulations. The demonstration of the actual formation of a drug-cyclodextrin inclusion complex in solution does not guarantee its existence also in the solid state. Moreover, the technique used to prepare the solid complex can strongly influence the properties of the final product. Therefore, an appropriate characterization of the drug-cyclodextrin solid systems obtained has also a key role in driving in the choice of the most effective preparation method, able to maximize host-guest interactions. The analytical characterization of drug-cyclodextrin solid systems and the assessment of the actual inclusion complex formation is not a simple task and involves the combined use of several analytical techniques, whose results have to be evaluated together. The objective of the present review is to present a general prospect of the principal analytical techniques which can be employed for a suitable characterization of drug-cyclodextrin systems in the solid state, evidencing their respective potential advantages and limits. The applications of each examined technique are described and discussed by pertinent examples from literature. PMID:25743620

  3. 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. PMID:24287055

  4. 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.

  5. 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…

  6. 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]…

  7. 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…

  8. 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.

  9. 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.

  10. 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.

  11. A framework for selecting analytical techniques in profiling authentic and counterfeit Viagra and Cialis.

    PubMed

    Anzanello, Michel J; Ortiz, Rafael S; Limberger, Renata; Mariotti, Kristiane

    2014-02-01

    Several analytical techniques aimed at profiling drugs are deemed costly and time consuming, and may not be promptly available for analysis when required. This paper proposes a method for identifying the analytical techniques providing the most relevant data for classification of drug samples into authentic and unauthentic categories. For that matter, we integrate principal components analysis (PCA) to k-Nearest Neighbor (KNN) and Support Vector Machine (SVM) classification tools. PCA is first applied to data from five techniques, i.e., physical profile, X-ray fluorescence (XRF), direct infusion electrospray ionization mass spectrometry (ESI-MS), active pharmacological ingredients profile (ultra performance liquid chromatography, UPLC-MS), and infrared spectroscopic profile (ATR-FTIR). Subsets of PCA scores are then combined with a "leave one subset out at a time" approach, and the classification accuracy using KNN and SVM evaluated after each subset is omitted. Subsets yielding the maximum accuracy indicate the techniques to be prioritized in profiling applications. When applied to data from Viagra and Cialis, the proposed method recommended using the data from UPLC-MS, physical profile and ATR-FTIR techniques, which increased the categorization accuracy. In addition, the SVM classification tool is suggested as more accurate when compared to the KNN. PMID:24447444

  12. 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. PMID:26605759

  13. An analytical calculation of the fluid load support fraction in a biphasic material: An alternative technique

    PubMed Central

    Stops, A.J.F.; Wilcox, R.K.; Jin, Z.

    2012-01-01

    Background The fluid load support fraction (WF/WT) can be used to define the mechanical contribution of the interstitial fluid (WF) to the total force (WT) in the deformation of cartilage. Traditionally, WF/WT is calculated using complex experimental setups or time-consuming micromechanical poroelastic Finite Element (FE) simulations. Aim To define and validate a fast and efficient technique to predict WF/WT using an analytical approach that can be applied without micromechanical detail or experimental measurement. Methodology Poroelastic FE simulations defined accurate values of WF/WT for a range of loading configurations and were used to validate subsequent predictions. The analytical prediction of WF/WT used elastic contact mechanics to calculate WF, and viscoelastic FE representation to calculate WT. Subsequently, these independent calculations of WF and WT provided values of WF/WT that were compared with the poroelastic FE calculations. Results and discussion The analytical prediction of WF/WT proved effective and suitably accurate (mean difference S<0.05). This technique demonstrated how WF and WT can be determined independently, without a biphasic constitutive model. Here we used viscoelasticity to calculate WT as an example, however, WT could be measured experimentally or predicted computationally. PMID:23026695

  14. Analytic regularization for landmark-based image registration

    NASA Astrophysics Data System (ADS)

    Shusharina, Nadezhda; Sharp, Gregory

    2012-03-01

    Landmark-based registration using radial basis functions (RBF) is an efficient and mathematically transparent method for the registration of medical images. To ensure invertibility and diffeomorphism of the RBF-based vector field, various regularization schemes have been suggested. Here, we report a novel analytic method of RBF regularization and demonstrate its power for Gaussian RBF. Our analytic formula can be used to obtain a regularized vector field from the solution of a system of linear equations, exactly as in traditional RBF, and can be generalized to any RBF with infinite support. We statistically validate the method on global registration of synthetic and pulmonary images. Furthermore, we present several clinical examples of multistage intensity/landmark-based registrations, where regularized Gaussian RBF are successful in correcting locally misregistered areas resulting from automatic B-spline registration. The intended ultimate application of our method is rapid, interactive local correction of deformable registration with a small number of mouse clicks.

  15. A Hybrid Analytic Element Universal Kriging Interpolation Technique Built in the Open Source R Environment

    NASA Astrophysics Data System (ADS)

    Tonkin, M. J.; Kennel, J.; Huber, W.; Lambie, J.

    2013-12-01

    A hybrid interpolation technique based on universal kriging (UK), originally developed in Fortran for computational expediency, has recently been translated into the open source R environment. The hybrid code was designed for water level mapping using elements common to the analytic element method (AEM) community such as point sink/sources, line sink/sources and hydraulic barriers (Karanovic et al, 2009). Translation to the R environment brought numerous advantages, including the ability to employ the object-oriented structure to extend UK to interpolate multiple datasets simultaneously. This extension of UK, referred to as Multi-Event Universal Kriging (MEUK; Tonkin et al, in review), was developed specifically to produce a sequence of maps using sample data obtained on multiple occasions that are separated in time (events). Unlike UK, which computes interpolation weights for each event by constructing and solving a system of kriging equations for each event using data obtained only from that event, independently of all other events, MEUK computes the interpolation weights required for all events simultaneously by constructing and solving a single system of kriging equations using the data obtained from all events. The most significant advantage of MEUK over UK is that the analyst can condition trend (drift) coefficients on either a subset or the entirety of the multi-event sample dataset, according to conceptual understanding of the site. Here, this particular advantage is illustrated by applying MEUK to undertake multi-event spatio-temporal water level data interpolation and generate a capture frequency map (CFM: Karanovic et al, 2009). MEUK has been implemented in the R package 'MEUK' which employs the R gstat geostatistical package (Pebesma, E.J., 2004).

  16. Analytical techniques for the evaluation of asymptotic matrix elements in electromagnetic problems

    NASA Astrophysics Data System (ADS)

    Park, Seong-Ook

    1997-07-01

    Analytical solutions of the asymptotic part of impedance matrix elements, whose integrand contains either a singularity or exhibits a strongly oscillatory behavior, are developed for the analysis of various geometries. These developed formulas are applied using the Method of Moments (MoM), to the analysis of wire antennas, planar transmission lines, and printed circuits including microstrip dipoles, asymmetric gap discontinuities, and arbitrary shapes of planar circuits, where computational speed and accuracy are important. The first example considered is the singularity treatment in integrands of wire-type antenna problems. To overcome the problem, first the singularity is subtracted out, and then this part is integrated analytically in the transform domain. Asymptotic matrix elements of the multilayer planar transmission lines are solved analytically by using Chebyshev polynomial basis functions in the spectral domain. These results are applied to open and coupled microstrip lines. The analysis of printed circuits involves Sommerfeld-type integrals which are extremely difficult to evaluate. To enhance the speed and accuracy of Sommerfeld-type integrals, this dissertation, for the first time, presents an analytical transformation technique. This formulation allows the infinite double integral of the asymptotic part of the impedance matrix to be transformed into a finite one-dimensional integral. Using this approach, the asymptotic part of self and mutual interactions between the triangular edge mode basis functions, along an electrically narrow strip, is solved analytically. These results are applied to microstrip dipoles and asymmetric gap discontinuities. This formula provides highly accurate results with minimal computational effort. This work is also extended to roof- top subdomain basis functions, and the obtained results can be used to solve arbitrarily shaped planar geometries. As an example, computed results of the Radar Cross Section (RCS) of a microstrip

  17. 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. PMID:25045677

  18. Big Data Analytics in Immunology: A Knowledge-Based Approach

    PubMed Central

    Zhang, Guang Lan

    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. PMID:25045677

  19. 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).

  20. Analytical techniques for characterization of cyclodextrin complexes in aqueous solution: a review.

    PubMed

    Mura, Paola

    2014-12-01

    Cyclodextrins are cyclic oligosaccharides endowed with a hydrophilic outer surface and a hydrophobic inner cavity, able to form inclusion complexes with a wide variety of guest molecules, positively affecting their physicochemical properties. In particular, in the pharmaceutical field, cyclodextrin complexation is mainly used to increase the aqueous solubility and dissolution rate of poorly soluble drugs, and to enhance their bioavailability and stability. Analytical characterization of host-guest interactions is of fundamental importance for fully exploiting the potential benefits of complexation, helping in selection of the most appropriate cyclodextrin. The assessment of the actual formation of a drug-cyclodextrin inclusion complex and its full characterization is not a simple task and often requires the use of different analytical methods, whose results have to be combined and examined together. The purpose of the present review is to give, as much as possible, a general overview of the main analytical tools which can be employed for the characterization of drug-cyclodextrin inclusion complexes in solution, with emphasis on their respective potential merits, disadvantages and limits. Further, the applicability of each examined technique is illustrated and discussed by specific examples from literature. PMID:24680374

  1. 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.

  2. Feature-Based Registration Techniques

    NASA Astrophysics Data System (ADS)

    Lorenz, Cristian; Klinder, Tobias; von Berg, Jens

    In contrast to intensity-based image registration, where a similarity measure is typically evaluated at each voxel location, feature-based registration works on a sparse set of image locations. Therefore, it needs an explicit step of interpolation to supply a dense deformation field. In this chapter, the application of feature-based registration to pulmonary image registration as well as hybrid methods, combining feature-based with intensity-based registration, is discussed. In contrast to pure feature based registration methods, hybrid methods are increasingly proposed in the pulmonary context and have the potential to out-perform purely intensity based registration methods. Available approaches will be classified along the categories feature type, correspondence definition, and interpolation type to finally achieve a dense deformation field.

  3. 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.

  4. 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. PMID:25542354

  5. 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

  6. 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

  7. General analytical schemes for the characterization of pectin-based edible gelled systems.

    PubMed

    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

  8. 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…

  9. MULTIELEMENTAL ANALYTICAL TECHNIQUES FOR HAZARDOUS WASTE ANALYSIS: THE STATE-OF-THE-ART

    EPA Science Inventory

    Based on a comprehensive review of the literature, the multielemental techniques of inductively coupled plasma optical emission spectroscopy (ICP), x-ray fluorescence (XRF) and instrumental neutron activation analysis (INAA) have been compared for the determination of antimony, a...

  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. A Web-based Geovisual Analytical System for Climate Studies

    NASA Astrophysics Data System (ADS)

    Sun, M.; Li, J.; Yang, C.; Schmidt, G. A.; Bambacus, M.; Cahalan, R.; Huang, Q.; Xu, C.; Noble, E.

    2012-12-01

    Climate studies involve petabytes of spatiotemporal datasets that are produced and archived at distributed computing resources. Scientists need an intuitive and convenient tool to explore the distributed spatiotemporal data. Geovisual analytical tools have the potential to provide such an intuitive and convenient method for scientists to access climate data, discover the relationships between various climate parameters, and communicate the results across different research communities. However, implementing a geovisual analytical tool for complex climate data in a distributed environment poses several challenges. This paper reports our efforts in developing a web-based geovisual analytical system to support the analysis of climate data generated by Intergovernmental Panel on Climate Change (IPCC), Fourth Assessment Report (AR4) models. Using the ModelE developed by NASA Goddard Institute for Space Studies (GISS) as an example, we demonstrate that the system is able to 1) manage large volume datasets over the Internet, 2) visualize 3D/4D spatiotemporal data, 3) broker various spatiotemporal statistical analyses for climate research, and 4) support interactive data analysis and knowledge discovery. This research also provides an example of how to manage, disseminate, and analyze Big Data in the 21st century.

  12. NOVEL ANALYTICAL TECHNIQUES BASED ON AN ENHANCED ELECTRON ATTACHMENT PROCESS

    EPA Science Inventory

    Sensitive and selective detection of dense non-aqueous phase liquids (DNAPLs), volatile organic compounds (VOCs), and other toxic compounds such as polychlorinated biphenyls (PCBs), furan and dioxin, is an area of continuing importance for the DOE. During the past three years, we...

  13. 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

  14. 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. PMID:26922341

  15. Regional Variation in Analytical Techniques used in the Diagnosis and Monitoring of Porphyria: a Case for Harmonisation?

    PubMed Central

    Sies, Christiaan W; Cronin, Virginia; Florkowski, Christopher M; Gill, Jan; Grant, Janine; Poulos, Victor; Zoanetti, John

    2015-01-01

    Background: The Royal College of Pathologists of Australasia (RCPA) Porphyrin Quality Assurance Program assesses the measurement of urine, faecal, plasma and whole blood porphyrins and their components plus urinary porphobilinogen and delta aminolaevulinic acid and has laboratories enrolled from around the world. It was observed that there was a wide scatter in results submitted to some subsections of the program. Methods: A detailed questionnaire covering the analytical techniques used in the diagnosis of porphyria was sent to all laboratories enrolled in the RCPA Porphyrin Quality Assurance Program. Additionally, self-enrolment data over a five year period was examined for trends/changes in standardisation, reagent sources and analytical technique. Results: Twenty of the 45 laboratories enrolled in the Porphyrin Quality Assurance Program completed the survey, providing a snapshot of the analytical techniques used world-wide. Post survey self enrolment data indicated only little or no noticeable changes to analytical standardisation of techniques despite the continual lack of agreement of results in subsections of the External Quality Assurance program. Conclusions: While some aspects of porphyria testing are relatively consistent between laboratories, other diagnostic techniques vary widely. A wide variety of individualised reference intervals and reporting techniques is currently in use world-wide. While most of the participants in the survey are regional reference centres specialising in the diagnosis of porphyria and, as such, their diagnostic capability is not in question, international guidelines or global harmonisation of analytical techniques should allow better inter-laboratory comparisons to be made, ultimately improving diagnostic accuracy. PMID:26224896

  16. 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.

  17. 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

  18. Applications of surface analytical techniques for study of the interactions between mercury and fluorescent lamp materials.

    PubMed

    Dang, Twan A; Frisk, T A; Grossman, M W

    2002-08-01

    Several surface analytical techniques, including electron spectroscopy for chemical analysis (ESCA)(X-ray photoelectron spectroscopy) and sputtered neutral mass spectrometry (SNMS), were used to study the interaction between Hg and other components of fluorescent lamps, a very critical issue in lighting industries. Active sites, responsible for Hg interaction/deposition, can be successfully identified by comparing the x- y distribution (obtained by ESCA mapping) and depth distribution (available through SNMS) of respective lamp components with that of Hg. A correlation in both depth and x- y distribution is strong evidence of site preference for Hg interaction/deposition. A burial mechanism is, however, proposed when only depth distribution, not x- y, is correlated. Other modes of ESCA (high resolution, angle-resolved, etc.) were also helpful. Information about the valence states of the interacted Hg species would help to define the nature of the interaction. PMID:12185568

  19. Analytical techniques for the detection and identification of chemical warfare materials from environmental samples

    SciTech Connect

    Beaudry, W.T.; Weimaster, J.F.

    1995-06-01

    The detection and identification of chemical warfare (CW) material in diverse and complex matrices has become increasingly important to support the environmental clean-up of military and industrial sites that were historically used in the research, production, use, storage and/or demilitarization of chemical weapons. Reliable and defensible identification of hazardous materials (HM) is necessary to comply with the increasingly stringent regulations imposed by local, state, and federal agencies which govern handling, treatment, storage, and disposal of HM. In addition, before sites can be reutilized, existing HM must be properly identified so that the proper methods of removal, treatment and disposal can be determined. An overview of sample preparation and analytical techniques for the detection and identification of CW materials is presented in this paper.

  20. 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. PMID:14982018

  1. 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. PMID:23721687

  2. 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%. PMID:25585402

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

    PubMed

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

    2015-07-01

    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

  4. 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

  5. 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

  6. 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…

  7. 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. PMID:26547492

  8. 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

  9. Analysis of simulation technique for steady shock waves in materials with analytical equations of state.

    PubMed

    Reed, Evan J; Fried, Laurence E; Henshaw, William D; Tarver, Craig M

    2006-11-01

    We calculate and analyze a thermodynamic limit of a multiscale molecular dynamics based scheme that we have developed previously for simulating shock waves. We validate and characterize the performance of the former scheme for several simple cases. Using model equations of state for chemical reactions and kinetics in a gas and a condensed phase explosive, we show that detonation wave profiles computed using the computational scheme are in good agreement with the steady state wave profiles of hydrodynamic direct numerical simulations. We also characterize the stability of the technique when applied to detonation waves and describe a technique for determining the detonation shock speed. PMID:17280020

  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. A decision analytic approach to exposure-based chemical prioritization.

    PubMed

    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

  12. 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. PMID:10879843

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

  14. 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.

  15. 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.

  16. 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.

  17. An analytical study of reduced-gravity liquid reorientation using a simplified marker and cell technique

    NASA Technical Reports Server (NTRS)

    Betts, W. S., Jr.

    1972-01-01

    A computer program called HOPI was developed to predict reorientation flow dynamics, wherein liquids move from one end of a closed, partially filled, rigid container to the other end under the influence of container acceleration. The program uses the simplified marker and cell numerical technique and, using explicit finite-differencing, solves the Navier-Stokes equations for an incompressible viscous fluid. The effects of turbulence are also simulated in the program. HOPI can consider curved as well as straight walled boundaries. Both free-surface and confined flows can be calculated. The program was used to simulate five liquid reorientation cases. Three of these cases simulated actual NASA LeRC drop tower test conditions while two cases simulated full-scale Centaur tank conditions. It was concluded that while HOPI can be used to analytically determine the fluid motion in a typical settling problem, there is a current need to optimize HOPI. This includes both reducing the computer usage time and also reducing the core storage required for a given size problem.

  18. 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.

  19. 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. PMID:24515892

  20. 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

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

    DOE PAGESBeta

    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 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

  2. 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. PMID:26024896

  3. Quality control and analytical methods for baculovirus-based products.

    PubMed

    Roldão, António; Vicente, Tiago; Peixoto, Cristina; Carrondo, Manuel J T; Alves, Paula M

    2011-07-01

    Recombinant baculoviruses (rBac) are used for many different applications, ranging from bio-insecticides to the production of heterologous proteins, high-throughput screening of gene functions, drug delivery, in vitro assembly studies, design of antiviral drugs, bio-weapons, building blocks for electronics, biosensors and chemistry, and recently as a delivery system in gene therapy. Independent of the application, the quality, quantity and purity of rBac-based products are pre-requisites demanded by regulatory authorities for product licensing. To guarantee maximization utility, it is necessary to delineate optimized production schemes either using trial-and-error experimental setups ("brute force" approach) or rational design of experiments by aid of in silico mathematical models (Systems Biology approach). For that, one must define all of the main steps in the overall process, identify the main bioengineering issues affecting each individual step and implement, if required, accurate analytical methods for product characterization. In this review, current challenges for quality control (QC) technologies for up- and down-stream processing of rBac-based products are addressed. In addition, a collection of QC methods for monitoring/control of the production of rBac derived products are presented as well as innovative technologies for faster process optimization and more detailed product characterization. PMID:21784235

  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. 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. PMID:26319168

  6. Microfluidic paper-based analytical device for particulate metals.

    PubMed

    Mentele, Mallory M; Cunningham, Josephine; Koehler, Kirsten; Volckens, John; Henry, Charles S

    2012-05-15

    A microfluidic paper-based analytical device (μPAD) fabricated by wax printing was designed to assess occupational exposure to metal-containing aerosols. This method employs rapid digestion of particulate metals using microliters of acid added directly to a punch taken from an air sampling filter. Punches were then placed on a μPAD, and digested metals were transported to detection reservoirs upon addition of water. These reservoirs contained reagents for colorimetric detection of Fe, Cu, and Ni. Dried buffer components were used to set the optimal pH in each detection reservoir, while precomplexation agents were deposited in the channels between the sample and detection zones to minimize interferences from competing metals. Metal concentrations were quantified from color intensity images using a scanner in conjunction with image processing software. Reproducible, log-linear calibration curves were generated for each metal, with method detection limits ranging from 1.0 to 1.5 μg for each metal (i.e., total mass present on the μPAD). Finally, a standard incineration ash sample was aerosolized, collected on filters, and analyzed for the three metals of interest. Analysis of this collected aerosol sample using a μPAD showed good correlation with known amounts of the metals present in the sample. This technology can provide rapid assessment of particulate metal concentrations at or below current regulatory limits and at dramatically reduced cost. PMID:22489881

  7. 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

  8. Determination of Aerosol Oxidative Activity using Silver Nanoparticle Aggregation on Paper-Based Analytical Devices

    PubMed Central

    Dungchai, Wijitar; Sameenoi, Yupaporn; Chailapakul, Orawon; Volckens, John; Henry, Charles S.

    2013-01-01

    Airborne particulate matter (PM) pollution significantly impacts human health, but the cellular mechanisms of PM-induced toxicity remain poorly understood. A leading hypothesis on the effects of inhaled PM involves the generation of cellular oxidative stress. To investigate PM-induced oxidative stress, analytical methods have been developed to study the chemical oxidation of dithiothreitol (DTT) in the presence of PM. Although DTT readily reacts with several forms of reactive oxygen species, this molecule is not endogenously produced in biological systems. Glutathione (GSH), on the other hand, is an endogenous antioxidant that is produced throughout the body and is directly involved in combating oxidative stress in the lungs and other tissues. We report here a new method for measuring aerosol oxidative activity that uses silver nanoparticle (AgNP) aggregation coupled to glutathione (GSH) oxidation in a paper-based analytical device. In this assay, the residual reduced GSH from the oxidation of reduced GSH to its disulfide induces the aggregation of AgNPs on a paper-based analytical device, which produces a reddish-brown product. Two methods for aerosol oxidative reactivity are presented: one based on change in color intensity using a traditional paper-based techniques and one based on the length of the color product formed using a distance-based device. These methods were validated against traditional spectroscopic assays for DTT and GSH that employ Elman’s reagent. No significant difference was found between the levels measured by all three GSH methods (our two paper-based devices and the traditional method) at the 95% confidence level. PM reactivity towards GSH was less than towards DTT most likely due to the difference in the oxidation potential between the two molecules. PMID:24067623

  9. Autofluorescence based diagnostic techniques for oral cancer

    PubMed Central

    Balasubramaniam, A. Murali; Sriraman, Rajkumari; Sindhuja, P.; Mohideen, Khadijah; Parameswar, R. Arjun; Muhamed Haris, K. T.

    2015-01-01

    Oral cancer is one of the most common cancers worldwide. Despite of various advancements in the treatment modalities, oral cancer mortalities are more, particularly in developing countries like India. This is mainly due to the delay in diagnosis of oral cancer. Delay in diagnosis greatly reduces prognosis of the treatment and also cause increased morbidity and mortality rates. Early diagnosis plays a key role in effective management of oral cancer. A rapid diagnostic technique can greatly aid in the early diagnosis of oral cancer. Now a day's many adjunctive oral cancer screening techniques are available for the early diagnosis of cancer. Among these, autofluorescence based diagnostic techniques are rapidly emerging as a powerful tool. These techniques are broadly discussed in this review. PMID:26538880

  10. 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.

  11. 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.

  12. 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.

  13. Synthesis and analytical characterisation of copper-based nanocoatings for bioactive stone artworks treatment.

    PubMed

    Ditaranto, Nicoletta; Loperfido, Sabrina; van der Werf, Inez; Mangone, Annarosa; Cioffi, Nicola; Sabbatini, Luigia

    2011-01-01

    Biological agents play an important role in the deterioration of cultural heritage causing aesthetic, biogeophysical and biogeochemical damages. Conservation is based on the use of preventive and remedial methods. The former aims at inhibiting biological attack, and the latter aims at eradicating the biological agents responsible for biodeterioration. Here, we propose the preparation and the analytical characterisation of copper-based nanocoating, capable of acting both as a remedy and to prevent microbial proliferation. Core-shell CuNPs are mixed with a silicon-based product, commonly used as a water-repellent/consolidant, to obtain a combined bioactive system to be applied on stone substrates. The resulting coatings exert a marked biological activity over a long period of time due to the continuous and controlled release of copper ions acting as biocides. To the best of our knowledge, this is the first time that a multifunctional material is proposed, combining the antimicrobial properties of nanostructured coatings with those of the formulations applied to the restoration of stone artworks. A complete characterisation based on a multi-technique analytical approach is presented. PMID:20972773

  14. 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.

  15. 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).

  16. 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.

  17. 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

  18. 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. PMID:16361218

  19. An analytical technique to extract surface information of negatively stained or heavy-metal shadowed organic materials within the TEM.

    PubMed

    Matsko, Nadejda B; Letofsky-Papst, Ilse; Albu, Mihaela; Mittal, Vikas

    2013-06-01

    Using a series of uranyl acetate stained or platinum-palladium shadowed organic samples, an empirical analytical method to extract surface information from energy-filtered transmission electron microscopy (EFTEM) images is described. The distribution of uranium or platinum-palladium atoms, which replicate the sample surface topography, have been mathematically extracted by dividing the image acquired in the valence bulk plasmon energy region (between 20 and 30 eV) by the image acquired at the carbon K ionization edge (between 284 and 300 eV). The resulting plasmon-to-carbon ratio (PCR) image may be interpreted as a precise metal replica of the sample surface. In contrast to conventional EFTEM elemental mapping, including an absolute quantification approach, this technique can be applied to 200-600 nm thick organic samples. A combination of conventional TEM and PCR imaging allows one to detect complementary transmission and topographical information with nanometer precision of the same area of carbon-based samples. The advantages and limitations of PCR imaging are highlighted. PMID:23570815

  20. 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.

  1. 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. PMID:24499071

  2. Laser Remote Sensing: Velocimetry Based Techniques

    NASA Astrophysics Data System (ADS)

    Molebny, Vasyl; Steinvall, Ove

    Laser-based velocity measurement is an area of the field of remote sensing where the coherent properties of laser radiation are the most exposed. Much of the published literature deals with the theory and techniques of remote sensing. We restrict our discussion to current trends in this area, gathered from recent conferences and professional journals. Remote wind sensing and vibrometry are promising in their new scientific, industrial, military, and biomedical applications, including improving flight safety, precise weapon correction, non-contact mine detection, optimization of wind farm operation, object identification based on its vibration signature, fluid flow studies, and vibrometry-associated diagnosis.

  3. 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.

  4. An Improved Analytic Signal Technique for the Depth and Structural Index from 2D Magnetic Anomaly Data

    NASA Astrophysics Data System (ADS)

    Ma, Guoqing; Du, Xiaojuan

    2012-12-01

    This paper presents a new inversion method for the interpretation of 2D magnetic anomaly data, which uses the combination of the analytic signal and its total gradient to estimate the depth and the nature (structural index) of an isolated magnetic source. However, our proposed method is sensitive to noise. In order to lower the effect of noise, we apply upward continuation technique to smooth the anomaly. Tests on synthetic noise-free and noise corrupted magnetic data show that the new method can successfully estimate the depth and the nature of the causative source. The practical application of the technique is applied to measured magnetic anomaly data from Jurh area, northeast China, and the inversion results are in agreement with the inversion results from Euler deconvolution of the analytic signal.

  5. Analytical performance of polymer-based microfluidic devices fabricated by computer numerical controlled machining.

    PubMed

    Mecomber, Justin S; Stalcup, Apryll M; Hurd, Doug; Halsall, H Brian; Heineman, William R; Seliskar, Carl J; Wehmeyer, Kenneth R; Limbach, Patrick A

    2006-02-01

    A study comparing the electrophoretic separation performance attainable from microchips molded by masters fabricated using conventional CNC machining techniques with commercial microchips, wire imprinted microchips, and microchips from LIGA molding devices is presented. An electrophoresis-based detection system using fluorescence microscopy was used to determine the analytical utility of these microchips. The separation performance of CNC microchips was comparable to commercially available microchips as well as those fabricated from LIGA masters. The important feature of the CNC machined masters is that they have rapid design-to-device times using routinely available machining tools. This low-cost prototyping approach provides a new entry point for researchers interested in thermoplastic microchips and can accelerate the development of polymer-based lab-on-a-chip devices. PMID:16448071

  6. 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.

  7. 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.

  8. 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.

  9. 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…

  10. 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

  11. Neutron-based nonintrusive inspection techniques

    NASA Astrophysics Data System (ADS)

    Gozani, Tsahi

    1997-02-01

    Non-intrusive inspection of large objects such as trucks, sea-going shipping containers, air cargo containers and pallets is gaining attention as a vital tool in combating terrorism, drug smuggling and other violation of international and national transportation and Customs laws. Neutrons are the preferred probing radiation when material specificity is required, which is most often the case. Great strides have been made in neutron based inspection techniques. Fast and thermal neutrons, whether in steady state or in microsecond, or even nanosecond pulses are being employed to interrogate, at high speeds, for explosives, drugs, chemical agents, and nuclear and many other smuggled materials. Existing neutron techniques will be compared and their current status reported.

  12. FDTD technique based crosstalk analysis of bundled SWCNT interconnects

    NASA Astrophysics Data System (ADS)

    Singh Duksh, Yograj; Kaushik, Brajesh Kumar; Agarwal, Rajendra P.

    2015-05-01

    The equivalent electrical circuit model of a bundled single-walled carbon nanotube based distributed RLC interconnects is employed for the crosstalk analysis. The accurate time domain analysis and crosstalk effect in the VLSI interconnect has emerged as an essential design criteria. This paper presents a brief description of the numerical method based finite difference time domain (FDTD) technique that is intended for estimation of voltages and currents on coupled transmission lines. For the FDTD implementation, the stability of the proposed model is strictly restricted by the Courant condition. This method is used for the estimation of crosstalk induced propagation delay and peak voltage in lossy RLC interconnects. Both functional and dynamic crosstalk effects are analyzed in the coupled transmission line. The effect of line resistance on crosstalk induced delay, and peak voltage under dynamic and functional crosstalk is also evaluated. The FDTD analysis and the SPICE simulations are carried out at 32 nm technology node for the global interconnects. It is observed that the analytical results obtained using the FDTD technique are in good agreement with the SPICE simulation results. The crosstalk induced delay, propagation delay, and peak voltage obtained using the FDTD technique shows average errors of 4.9%, 3.4% and 0.46%, respectively, in comparison to SPICE.

  13. ERGs, cone-isolating VEPs and analytical techniques in children with cone dysfunction syndromes.

    PubMed

    Kelly, John P; Crognale, Michael A; Weiss, Avery H

    2003-05-01

    Photoreceptor and post-receptoral function in children with congenital and acquired cone disorders was measured by full-field electroretinogram (ERG) and transient visual evoked potentials (VEPs). Subjects were five rod monochromats (RM), five with cone dystrophy (CD), and 30 controls. Patients were diagnosed by clinical findings, ERGs, and standard color vision tests. VEP stimuli were check reversals and color grating onsets that stimulated each photoreceptor type (L-, M-, or S-cones) or post-receptoral pathways (L-M, white/black). VEP signal-to-noise ratios (S/N) were calculated by Fourier analysis of VEP epochs. All RM patients showed extinguished cone ERGs. A near normal S-cone VEP was recorded from a blue-cone rod monochromat without any signal from the L- or M-cone stimuli. Two other RM patients were classified as incomplete RM based on a low-level VEP signal from either L- or M-cone stimuli. CD patients had mildly to severely reduced ERGs and VEPs were abnormal to all cone-isolating stimuli. The VEP S/N ratio was not significantly correlated with the amount of rod contrast in the color stimuli. Color VEPs provide an objective assessment of macular cone function in children with cone dysfunction syndromes that is more sensitive to residual central cone function than standard full-field ERGs. VEP techniques may be useful in the early detection of cone loss in children, especially in children who do not tolerate ERG testing. PMID:12737507

  14. 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.

  15. 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…

  16. An analytical technique for predicting the characteristics of a flexible wing equipped with an active flutter-suppression system and comparison with wind-tunnel data

    NASA Technical Reports Server (NTRS)

    Abel, I.

    1979-01-01

    An analytical technique for predicting the performance of an active flutter-suppression system is presented. This technique is based on the use of an interpolating function to approximate the unsteady aerodynamics. The resulting equations are formulated in terms of linear, ordinary differential equations with constant coefficients. This technique is then applied to an aeroelastic model wing equipped with an active flutter-suppression system. Comparisons between wind-tunnel data and analysis are presented for the wing both with and without active flutter suppression. Results indicate that the wing flutter characteristics without flutter suppression can be predicted very well but that a more adequate model of wind-tunnel turbulence is required when the active flutter-suppression system is used.

  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. Hydrocarbon microseepage mapping using signature based target detection techniques

    NASA Astrophysics Data System (ADS)

    Soydan, Hilal; Koz, Alper; Şebnem Düzgün, H.; Aydin Alatan, A.

    2015-10-01

    In this paper, we compare the conventional methods in hydrocarbon seepage anomalies with the signature based detection algorithms. The Crosta technique [1] is selected as a basement in the experimental comparisons for the conventional approach. The Crosta technique utilizes the characteristic bands of the searched target for principal component transformation in order to determine the components characterizing the target in interest. Desired Target Detection and Classification Algorithm (DTDCA), Spectral Matched Filter (SMF), and Normalized Correlation (NC) are employed for signature based target detection. Signature based target detection algorithms are applied to the whole spectrum benefiting from the information stored in all spectral bands. The selected methods are applied to a multispectral Advanced SpaceBorne Thermal Emission and Radiometer (ASTER) image of the study region, with an atmospheric correction prior to the realization of the algorithms. ASTER provides multispectral bands covering visible, short wave, and thermal infrared region, which serves as a useful tool for the interpretation of the areas with hydrocarbon anomalies. The exploration area is selected as Gemrik Anticline which is located in South East Anatolia, Adıyaman, Bozova Oil Field, where microseeps can be observed with almost no vegetation cover. The spectral signatures collected with Analytical Spectral Devices Inc. (ASD) spectrometer from the reference valley [2] have been utilized as an input to the signature based detection algorithms. The experiments have indicated that DTDCA and MF outperforms the Crosta technique by locating the microseepage patterns along the mitigation pathways with a better contrast. On the other hand, NC has not been able to map the searched target with a visible distinction. It is concluded that the signature based algorithms can be more effective than the conventional methods for the detection of microseepage induced anomalies.

  19. Quantification of Process Induced Disorder in Milled Samples Using Different Analytical Techniques

    PubMed Central

    Zimper, Ulrike; Aaltonen, Jaakko; McGoverin, Cushla M.; Gordon, Keith C.; Krauel-Goellner, Karen; Rades, Thomas

    2010-01-01

    The aim of this study was to compare three different analytical methods to detect and quantify the amount of crystalline disorder/ amorphousness in two milled model drugs. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Raman spectroscopy were used as analytical methods and indomethacin and simvastatin were chosen as the model compounds. These compounds partly converted from crystalline to disordered forms by milling. Partial least squares regression (PLS) was used to create calibration models for the XRPD and Raman data, which were subsequently used to quantify the milling-induced crystalline disorder/ amorphousness under different process conditions. In the DSC measurements the change in heat capacity at the glass transition was used for quantification. Differently prepared amorphous indomethacin standards (prepared by either melt quench cooling or cryo milling) were compared by principal component analysis (PCA) to account for the fact that the choice of standard ultimately influences the quantification outcome. Finally, the calibration models were built using binary mixtures of crystalline and quench cooled amorphous drug materials. The results imply that the outcome with respect to crystalline disorder for milled drugs depends on the analytical method used and the calibration standard chosen as well as on the drug itself. From the data presented here, it appears that XRPD tends to give a higher percentage of crystalline disorder than Raman spectroscopy and DSC for the same samples. For the samples milled under the harshest milling conditions applied (60 min, sixty 4 mm balls, 25 Hz) a crystalline disorder / amorphous content of 44.0% (XRPD), 10.8% (Raman spectroscopy) and 17.8% (DSC) were detected for indomethacin. For simvastatin 18.3% (XRPD), 15.5% (Raman spectroscopy) and 0% (DSC, no glass transition) crystalline disorder/ amorphousness were detected.

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

    PubMed

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

    2016-01-01

    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

  1. 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

  2. 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

  3. 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...

  4. Rapid Disaster Analysis based on SAR Techniques

    NASA Astrophysics Data System (ADS)

    Yang, C. H.; Soergel, U.

    2015-03-01

    Due to all-day and all-weather capability spaceborne SAR is a valuable means for rapid mapping during and after disaster. In this paper, three change detection techniques based on SAR data are discussed: (1) initial coarse change detection, (2) flooded area detection, and (3) linear-feature change detection. The 2011 Tohoku Earthquake and Tsunami is used as case study, where earthquake and tsunami events provide a complex case for this study. In (1), pre- and post-event TerraSAR-X images are coregistered accurately to produce a false-color image. Such image provides a quick and rough overview of potential changes, which is useful for initial decision making and identifies areas worthwhile to be analysed further in more depth. In (2), the post-event TerraSAR-X image is used to extract the flooded area by morphological approaches. In (3), we are interested in detecting changes of linear shape as indicator for modified man-made objects. Morphological approaches, e.g. thresholding, simply extract pixel-based changes in the difference image. However, in this manner many irrelevant changes are highlighted, too (e.g., farming activity, speckle). In this study, Curvelet filtering is applied in the difference image not only to suppress false alarms but also to enhance the change signals of linear-feature form (e.g. buildings) in settlements. Afterwards, thresholding is conducted to extract linear-shaped changed areas. These three techniques mentioned above are designed to be simple and applicable in timely disaster analysis. They are all validated by comparing with the change map produced by Center for Satellite Based Crisis Information, DLR.

  5. 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

  6. When are total concentrations not total? Factors affecting geochemical analytical techniques for measuring element concentrations in soil.

    PubMed

    McIlwaine, Rebekka; Cox, Siobhan F; Doherty, Rory

    2015-04-01

    Inductively coupled plasma (ICP) following aqua regia digestion and X-ray fluorescence (XRF) are both geochemical techniques used to determine 'total' concentrations of elements in soil. The aim of this study is to compare these techniques, identify elements for which inconsistencies occur and investigate why they arise. A study area (∼14,000 km(2)) with a variety of total concentration controls and a large geochemical dataset (n = 7950) was selected. Principal component analysis determined underlying variance in a dataset composed of both geogenic and anthropogenic elements. Where inconsistencies between the techniques were identified, further numerical and spatial analysis was completed. The techniques are more consistent for elements of geogenic sources and lead, whereas other elements of anthropogenic sources show less consistency within rural samples. XRF is affected by sample matrix, while the form of element affects ICP concentrations. Depending on their use in environmental studies, different outcomes would be expected from the techniques employed, suggesting the choice of analytical technique for geochemical analyses may be more critical than realised. PMID:25712881

  7. Some Techniques for Computer-Based Assessment in Medical Education.

    ERIC Educational Resources Information Center

    Mooney, G. A.; Bligh, J. G.; Leinster, S. J.

    1998-01-01

    Presents a system of classification for describing computer-based assessment techniques based on the level of action and educational activity they offer. Illustrates 10 computer-based assessment techniques and discusses their educational value. Contains 14 references. (Author)

  8. 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.

  9. 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

  10. An analytical technique for the analysis of airplane spin entry and recovery

    NASA Technical Reports Server (NTRS)

    Taylor, L. W., Jr.; Miller, G. K., Jr.

    1982-01-01

    The dynamic equations of motion for a spinning airplane are simplified to facilitate the analysis of spin entry and recovery maneuvers. Solutions of a nonlinear, first order equation for spin rate enable calculation of spin entry and recovery times and control required for recovery. The analysis is applied to a light airplane for which both aerodynamic data, rotory balance wind tunnel tests, and spin flight test data have been obtained. A comparison of predicted and actual transient spin responses is made which supports the validity of the analytical approach taken but which also illustrates the difficulty in obtaining accurate aerodynamic data for spinning airplanes. Certain normalized parameters of the reduced state spin equation suggest criteria for assessing the transient spin characteristics of light airplanes.

  11. 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.

  12. 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. PMID:26751854

  13. 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. PMID:26990591

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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. PMID:25105261

  19. 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.

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

    PubMed

    Gomes, Bruna Ferreira; 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, Cu(2+), Ni(2+), Cr(3+), and Mn(2+), 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

  1. 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

  2. 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)

  3. 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. PMID:25742012

  4. 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

  5. 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.

  6. Shaded computer graphic techniques for visualizing and interpreting analytic fluid flow models

    NASA Technical Reports Server (NTRS)

    Parke, F. I.

    1981-01-01

    Mathematical models which predict the behavior of fluid flow in different experiments are simulated using digital computers. The simulations predict values of parameters of the fluid flow (pressure, temperature and velocity vector) at many points in the fluid. Visualization of the spatial variation in the value of these parameters is important to comprehend and check the data generated, to identify the regions of interest in the flow, and for effectively communicating information about the flow to others. The state of the art imaging techniques developed in the field of three dimensional shaded computer graphics is applied to visualization of fluid flow. Use of an imaging technique known as 'SCAN' for visualizing fluid flow, is studied and the results are presented.

  7. 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.

  8. 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.

  9. 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.

  10. categoryCompare, an analytical tool based on feature annotations

    PubMed Central

    Flight, Robert M.; Harrison, Benjamin J.; Mohammad, Fahim; Bunge, Mary B.; Moon, Lawrence D. F.; Petruska, Jeffrey C.; Rouchka, Eric C.

    2014-01-01

    Assessment of high-throughput—omics data initially focuses on relative or raw levels of a particular feature, such as an expression value for a transcript, protein, or metabolite. At a second level, analyses of annotations including known or predicted functions and associations of each individual feature, attempt to distill biological context. Most currently available comparative- and meta-analyses methods are dependent on the availability of identical features across data sets, and concentrate on determining features that are differentially expressed across experiments, some of which may be considered “biomarkers.” The heterogeneity of measurement platforms and inherent variability of biological systems confounds the search for robust biomarkers indicative of a particular condition. In many instances, however, multiple data sets show involvement of common biological processes or signaling pathways, even though individual features are not commonly measured or differentially expressed between them. We developed a methodology, categoryCompare, for cross-platform and cross-sample comparison of high-throughput data at the annotation level. We assessed the utility of the approach using hypothetical data, as well as determining similarities and differences in the set of processes in two instances: (1) denervated skin vs. denervated muscle, and (2) colon from Crohn's disease vs. colon from ulcerative colitis (UC). The hypothetical data showed that in many cases comparing annotations gave superior results to comparing only at the gene level. Improved analytical results depended as well on the number of genes included in the annotation term, the amount of noise in relation to the number of genes expressing in unenriched annotation categories, and the specific method in which samples are combined. In the skin vs. muscle denervation comparison, the tissues demonstrated markedly different responses. The Crohn's vs. UC comparison showed gross similarities in inflammatory

  11. 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.

  12. 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.

  13. The characterisation of three different coal samples by means of various analytical techniques

    NASA Astrophysics Data System (ADS)

    Waanders, F. B.; van Dyk, J. C.; Prinsloo, C. J.

    2009-04-01

    Three coal samples were investigated by means of room temperature Fe-Mössbauer analyses, high temperature X-ray diffraction measurements (HT-XRD), electron microscopy analyses (SEM) of the slag and the ash fusion temperatures (AFT) of the coal samples were determined. FactSage modelling was done for the Fe-containing species. Mössbauer analyses showed that the one Southern hemisphere coal contained pyrite (1.5%) whilst the other sample contained siderite (4%). The Northern hemisphere coal contained a large amount (27%) of pyrite. After heating the coal in air, the ash contained a glass and hematite. The SEM analyses of the slag that formed, showed that hematite was present, in agreement with high temperature X-ray diffraction work. The ash fusion temperatures, as determined with FactSage modelling and the value as determined by the standard analytical methods, were found to vary between 1,300°C and 1,470°C.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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?

  2. 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.

  3. 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…

  4. 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

  5. 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

  6. 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

  7. Base flow separation: A comparison of analytical and mass balance methods

    NASA Astrophysics Data System (ADS)

    Lott, Darline A.; Stewart, Mark T.

    2016-04-01

    Base flow is the ground water contribution to stream flow. Many activities, such as water resource management, calibrating hydrological and climate models, and studies of basin hydrology, require good estimates of base flow. The base flow component of stream flow is usually determined by separating a stream hydrograph into two components, base flow and runoff. Analytical methods, mathematical functions or algorithms used to calculate base flow directly from discharge, are the most widely used base flow separation methods and are often used without calibration to basin or gage-specific parameters other than basin area. In this study, six analytical methods are compared to a mass balance method, the conductivity mass-balance (CMB) method. The base flow index (BFI) values for 35 stream gages are obtained from each of the seven methods with each gage having at least two consecutive years of specific conductance data and 30 years of continuous discharge data. BFI is cumulative base flow divided by cumulative total discharge over the period of record of analysis. The BFI value is dimensionless, and always varies from 0 to 1. Areas of basins used in this study range from 27 km2 to 68,117 km2. BFI was first determined for the uncalibrated analytical methods. The parameters of each analytical method were then calibrated to produce BFI values as close to the CMB derived BFI values as possible. One of the methods, the power function (aQb + cQ) method, is inherently calibrated and was not recalibrated. The uncalibrated analytical methods have an average correlation coefficient of 0.43 when compared to CMB-derived values, and an average correlation coefficient of 0.93 when calibrated with the CMB method. Once calibrated, the analytical methods can closely reproduce the base flow values of a mass balance method. Therefore, it is recommended that analytical methods be calibrated against tracer or mass balance methods.

  8. Ion implanters contamination on wafer surface analyzed by ToF-SIMS and SPV analytical techniques

    NASA Astrophysics Data System (ADS)

    Ricciari, R.; Bertini, M.; Ferlito, E. P.; Pizzo, G.; Anastasi, G.; Mello, D.; Franco, G.

    2007-04-01

    In ULSI processes, metallic contamination controls are very important issues. For the ion implantation process it is known that several sources of contaminations still need to be controlled: metals from sputtering of the apertures or wafer holders, Na+ contaminations from filament impurities and messy maintenance procedure. ToF-SIMS is one of the most promising candidates to perform in-line surface analysis due to its high sensitivity. It is very common to use surface photo-voltage (SPV) techniques to control ion implanter equipments but this kind of analysis is an indirect measure for metallic contamination. The aim of this work is to study the possibility to use ToF-SIMS instead of SPV for in line equipment contamination monitoring. For this reason a comparison between SPV and ToF-SIMS data occurred. Good correlation between the data is shown; moreover ToF-SIMS spectra give detailed information about the other contaminations present on the wafer surface.

  9. 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.

  10. 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.