WorldWideScience

Sample records for direct chemical analysis

  1. Direct chemical analysis of frozen ice cores by UV-laser ablation ICPMS

    DEFF Research Database (Denmark)

    Müller, Wolfgang; Shelley, J. Michael G.; Rasmussen, Sune Olander

    2011-01-01

    Cryo-cell UV-LA-ICPMS is a new technique for direct chemical analysis of frozen ice cores at high spatial resolution (dust records and annual layer signatures at unprecedented spatial/time resolution. Uniquely......, the location of cation impurities relative to grain boundaries in recrystallized ice can be assessed....

  2. Chemical Security Analysis Center

    Data.gov (United States)

    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  3. Direct Laser Ablation and Ionization of Solids for Chemical Analysis by Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Holt, J K; Nelson, E J; Klunder, G L [Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

    2007-04-15

    A laser ablation/ionization mass spectrometer system is described for the direct chemical analysis of solids. An Nd:YAG laser is used for ablation and ionization of the sample in a quadrupole ion trap operated in an ion-storage (IS) mode that is coupled with a reflectron time-of-flight mass spectrometer (TOF-MS). Single pulse experiments have demonstrated simultaneous detection of up to 14 elements present in glasses in the ppm range. However, detection of the components has produced non-stoichiometric results due to difference in ionization potentials and fractionation effects. Time-of-flight secondary ionization mass spectrometry (TOF-SIMS) was used to spatially map elemental species on the surface and provide further evidence of fractionation effects. Resolution (m/{delta}m) of 1500 and detection limits of approximately 10 pg have been achieved with a single laser pulse. The system configuration and related operating principles for accurately measuring low concentrations of isotopes are described.

  4. Ultrasonic nebulization extraction/low pressure photoionization mass spectrometry for direct analysis of chemicals in matrices.

    Science.gov (United States)

    Liu, Chengyuan; Zhu, Yanan; Zhou, Zhongyue; Yang, Jiuzhong; Qi, Fei; Pan, Yang

    2015-09-03

    A novel ultrasonic nebulization extraction/low-pressure photoionization (UNE-LPPI) system has been designed and employed for the rapid mass spectrometric analysis of chemicals in matrices. An ultrasonic nebulizer was used to extract the chemicals in solid sample and nebulize the solvent in the nebulization cell. Aerosols formed by ultrasonic were evaporated by passing through a transferring tube, and desolvated chemicals were ionized by the emitted light (10.6 eV) from a Krypton discharge lamp at low pressure (∼68 Pa). First, a series of semi/non-volatile compounds with different polarities, such as polycyclic aromatic hydrocarbons (PAHs), amino acids, dipeptides, drugs, nucleic acids, alkaloids, and steroids were used to test the system. Then, the quantification capability of UNE-LPPI was checked with: 1) pure chemicals, such as 9,10-phenanthrenequinone and 1,4-naphthoquinone dissolved in solvent; 2) soil powder spiked with different amounts of phenanthrene and pyrene. For pure chemicals, the correlation coefficient (R(2)) for the standard curve of 9,10-phenanthrenequinone in the range of 3 ng-20 μg mL(-1) was 0.9922, and the measured limits of detection (LOD) was 1 ng ml(-1). In the case of soil powder, linear relationships for phenanthrene and pyrene from 10 to 400 ng mg(-1) were obtained with correlation coefficients of 0.9889 and 0.9893, respectively. At last, the feasibility of UNE-LPPI for the detection of chemicals in real matrices such as tablets and biological tissues (tea, Citrus aurantium peel and sage (Salvia officinalis) leaf) were successfully demonstrated. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Chemical discrimination of lubricant marketing types using direct analysis in real time time-of-flight mass spectrometry.

    Science.gov (United States)

    Maric, Mark; Harvey, Lauren; Tomcsak, Maren; Solano, Angelique; Bridge, Candice

    2017-06-30

    In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time time of flight mass spectrometry (DART-TOFMS). The instrumental data was analyzed by multivariate statistics including hierarchal cluster analysis, principal component analysis, and linear discriminant analysis. By interpreting the mass spectral data with multivariate statistics, 12 discrete groupings were identified, indicating inherent chemical diversity not only between but within the three main marketing groups. A number of unique chemical markers, both major and minor, were identified, other than the three main chemical components (i.e. PEG, PDMS and nonoxynol-9) currently used for lubricant classification. The data was validated by a stratified 20% withheld cross-validation which demonstrated that there was minimal overlap between the groupings. Based on the groupings identified and unique features of each group, a highly discriminating statistical model was then developed that aims to provide the foundation for the development of a forensic lubricant database that may eventually be applied to casework. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Leaf spray: direct chemical analysis of plant material and living plants by mass spectrometry.

    Science.gov (United States)

    Liu, Jiangjiang; Wang, He; Cooks, R Graham; Ouyang, Zheng

    2011-10-15

    The chemical constituents of intact plant material, including living plants, are examined by a simple spray method that provides real-time information on sugars, amino acids, fatty acids, lipids, and alkaloids. The experiment is applicable to various plant parts and is demonstrated for a wide variety of species. An electrical potential is applied to the plant and its natural sap, or an applied solvent generates an electrospray that carries endogenous chemicals into an adjacent benchtop or miniature mass spectrometer. The sharp tip needed to create a high electric field can be either natural (e.g., bean sprout) or a small nick can be cut in a leaf, fruit, bark, etc. Stress-induced changes in glucosinolates can be followed on the minute time scale in several plants, including potted vegetables. Differences in spatial distributions and the possibility of studying plant metabolism are demonstrated. © 2011 American Chemical Society

  7. Direct analysis of volatile organic compounds in foods by headspace extraction atmospheric pressure chemical ionisation mass spectrometry.

    Science.gov (United States)

    Perez-Hurtado, P; Palmer, E; Owen, T; Aldcroft, C; Allen, M H; Jones, J; Creaser, C S; Lindley, M R; Turner, M A; Reynolds, J C

    2017-11-30

    The rapid screening of volatile organic compounds (VOCs) by direct analysis has potential applications in the areas of food and flavour science. Currently, the technique of choice for VOC analysis is gas chromatography/mass spectrometry (GC/MS). However, the long chromatographic run times and elaborate sample preparation associated with this technique have led a movement towards direct analysis techniques, such as selected ion flow tube mass spectrometry (SIFT-MS), proton transfer reaction mass spectrometry (PTR-MS) and electronic noses. The work presented here describes the design and construction of a Venturi jet-pump-based modification for a compact mass spectrometer which enables the direct introduction of volatiles for qualitative and quantitative analysis. Volatile organic compounds were extracted from the headspace of heated vials into the atmospheric pressure chemical ionization source of a quadrupole mass spectrometer using a Venturi pump. Samples were analysed directly with no prior sample preparation. Principal component analysis (PCA) was used to differentiate between different classes of samples. The interface is shown to be able to routinely detect problem analytes such as fatty acids and biogenic amines without the requirement of a derivatisation step, and is shown to be able to discriminate between four different varieties of cheese with good intra and inter-day reproducibility using an unsupervised PCA model. Quantitative analysis is demonstrated using indole standards with limits of detection and quantification of 0.395 μg/mL and 1.316 μg/mL, respectively. The described methodology can routinely detect highly reactive analytes such as volatile fatty acids and diamines without the need for a derivatisation step or lengthy chromatographic separations. The capability of the system was demonstrated by discriminating between different varieties of cheese and monitoring the spoilage of meats. © 2017 The Authors. Rapid Communications in Mass

  8. Evaluating legacy contaminants and emerging chemicals in marine environments using adverse outcome pathways and biological effects-directed analysis

    International Nuclear Information System (INIS)

    Hutchinson, Thomas H.; Lyons, Brett P.; Thain, John E.; Law, Robin J.

    2013-01-01

    important scientific, economic and health challenges. In order to meet these challenges and pursue cost-effective scientific approaches that can provide evidence necessary to support policy needs (e.g. the European Marine Strategy Framework Directive), it is widely recognised that there is a need to (i) provide marine exposure assessments for priority contaminants using a range of validated models, passive samplers and biomarkers; (ii) integrate chemical monitoring data with biological effects data across spatial and temporal scales (including quality controls); and (iii) strengthen the evidence base to understand the relationship between exposure to complex chemical mixtures, biological and ecological impacts through integrated approaches and molecular data (e.g. genomics, proteomics and metabolomics). Additionally, we support the widely held view that (iv) that rather than increasing the analytical chemistry monitoring of large number of emerging contaminants, it will be important to target analytical chemistry towards key groups of chemicals of concern using effects-directed analysis. It is also important to evaluate to what extent existing biomarkers and bioassays can address various classes of emerging chemicals using the adverse outcome pathway (AOP) approach now being developed by the Organization for Economic Cooperation and Development (OECD) with respect to human toxicology and ecotoxicology

  9. Evaluating legacy contaminants and emerging chemicals in marine environments using adverse outcome pathways and biological effects-directed analysis.

    Science.gov (United States)

    Hutchinson, Thomas H; Lyons, Brett P; Thain, John E; Law, Robin J

    2013-09-30

    important scientific, economic and health challenges. In order to meet these challenges and pursue cost-effective scientific approaches that can provide evidence necessary to support policy needs (e.g. the European Marine Strategy Framework Directive), it is widely recognised that there is a need to (i) provide marine exposure assessments for priority contaminants using a range of validated models, passive samplers and biomarkers; (ii) integrate chemical monitoring data with biological effects data across spatial and temporal scales (including quality controls); and (iii) strengthen the evidence base to understand the relationship between exposure to complex chemical mixtures, biological and ecological impacts through integrated approaches and molecular data (e.g. genomics, proteomics and metabolomics). Additionally, we support the widely held view that (iv) that rather than increasing the analytical chemistry monitoring of large number of emerging contaminants, it will be important to target analytical chemistry towards key groups of chemicals of concern using effects-directed analysis. It is also important to evaluate to what extent existing biomarkers and bioassays can address various classes of emerging chemicals using the adverse outcome pathway (AOP) approach now being developed by the Organization for Economic Cooperation and Development (OECD) with respect to human toxicology and ecotoxicology. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  10. Chemical process hazards analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.

  11. Direct atmospheric pressure chemical ionization-tandem mass spectrometry for the continuous real-time trace analysis of benzene, toluene, ethylbenzene, and xylenes in ambient air.

    Science.gov (United States)

    Badjagbo, Koffi; Picard, Pierre; Moore, Serge; Sauvé, Sébastien

    2009-05-01

    Real-time monitoring of benzene, toluene, ethylbenzene, and xylenes (BTEX) in ambient air is essential for the early warning detection associated with the release of these hazardous chemicals and in estimating the potential exposure risks to humans and the environment. We have developed a tandem mass spectrometry (MS/MS) method for continuous real-time determination of ambient trace levels of BTEX. The technique is based on the sampling of air via an atmospheric pressure inlet directly into the atmospheric pressure chemical ionization (APCI) source. The method is linear over four orders of magnitude, with correlation coefficients greater than 0.996. Low limits of detection in the range 1-2 microg/m(3) are achieved for BTEX. The reliability of the method was confirmed through the evaluation of quality parameters such as repeatability and reproducibility (relative standard deviation below 8% and 10%, respectively) and accuracy (over 95%). The applicability of this method to real-world samples was evaluated through measurements of BTEX levels in real ambient air samples and results were compared with a reference GC-FID method. This direct APCI-MS/MS method is suitable for real-time analysis of BTEX in ambient air during regulation surveys as well as for the monitoring of industrial processes or emergency situations.

  12. Direct, rapid RNA sequence analysis

    International Nuclear Information System (INIS)

    Peattie, D.A.

    1987-01-01

    The original methods of RNA sequence analysis were based on enzymatic production and chromatographic separation of overlapping oligonucleotide fragments from within an RNA molecule followed by identification of the mononucleotides comprising the oligomer. Over the past decade the field of nucleic acid sequencing has changed dramatically, however, and RNA molecules now can be sequenced in a variety of more streamlined fashions. Most of the more recent advances in RNA sequencing have involved one-dimensional electrophoretic separation of 32 P-end-labeled oligoribonucleotides on polyacrylamide gels. In this chapter the author discusses two of these methods for determining the nucleotide sequences of RNA molecules rapidly: the chemical method and the enzymatic method. Both methods are direct and degradative, i.e., they rely on fragmatic and chemical approaches should be utilized. The single-strand-specific ribonucleases (A, T 1 , T 2 , and S 1 ) provide an efficient means to locate double-helical regions rapidly, and the chemical reactions provide a means to determine the RNA sequence within these regions. In addition, the chemical reactions allow one to assign interactions to specific atoms and to distinguish secondary interactions from tertiary ones. If the RNA molecule is small enough to be sequenced directly by the enzymatic or chemical method, the probing reactions can be done easily at the same time as sequencing reactions

  13. Qualitative and quantitative chemical investigation of orthopedic alloys by combining wet digestion, spectro analytical methods and direct solid analysis

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Caio M.; Castro, Jeyne P.; Sperança, Marco A.; Fialho, Lucimar L.; Nóbrega, Joaquim A.; Pereira-Filho, Edenir R., E-mail: erpf@ufscar.br [Universidade Federal de São Carlos (GAIA/UFSCar), SP (Brazil). Grupo de Análise Instrumental Aplicada

    2018-05-01

    In this study, two laser-based techniques, laser-induced breakdown spectroscopy (LIBS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used for analytical signal evaluation of Ti, Al, and V and investigation of possible harmful elements eventually present as minor elements in Ti alloys. Due to the lack of certified reference materials, samples were also analyzed by wavelength dispersive X-ray fluorescence (WDXRF) and inductively coupled plasma optical emission spectrometry (ICP OES) after microwave-assisted digestion. To maximize the efficiency of LIBS and LA-ICP-MS, operational conditions were adjusted aiming to find optimal analytical performance. LIBS showed several Ti emission lines and few signals for Al and V. LA-ICP-MS was able to detect all three major constituents. For quantitative analysis, the correlation of intensity signals from LIBS analysis with reference values obtained by ICP OES was not successful, showing that there are still difficulties for quantification using solid samples. Measurements using ICP OES showed that additionally to major constituents, only Fe was present in concentrations around 0.2%. Analysis by WDXRF confirmed the presence of Fe. Results using both methods, i.e., ICP OES and WDXRF, were in good agreement. (author)

  14. Investigation of chemical modifiers for sulfur determination in diesel fuel samples by high-resolution continuum source graphite furnace molecular absorption spectrometry using direct analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Charles S. [Instituto Federal Sul-rio-grandense, Câmpus Pelotas, Pelotas, RS (Brazil); Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Universidade Federal de Santa Catarina, Departamento de Química, Florianópolis, SC (Brazil); Andrade, Jailson B. [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2015-06-01

    High-resolution continuum source graphite furnace molecular absorption spectrometry has been applied for sulfur determination in diesel fuel. The sharp rotational lines of the carbon monosulfide molecule (formed during the vaporization step) were used to measure the absorbance. The analytical line at 258.056 nm was monitored using the sum of three pixels. Different chemical modifiers were investigated and the mixture of palladium and magnesium was used as chemical modifier in combination with iridium as permanent modifier. L-Cysteine was chosen as sulfur standard and the calibration was done against aqueous standard solutions. The proposed method was applied for the analyses of four diesel samples: two S10 samples and two S500 samples. The trueness of the method was checked with a certified reference material (CRM) of sulfur in diesel fuel (NIST 2724b). Accurate results, for samples and CRM, were achieved after a dilution with propan-1-ol. The following figures of merit were obtained: characteristic mass of 17 ± 3 ng, limit of detection and limit of quantification of 1.4 mg kg{sup −1} and 4.7 mg kg{sup −1}, respectively. - Highlights: • Ir, Ru and Zr were investigated as permanent modifiers. • Ca, Mg, Pd and Pd/Mg were investigated as modifiers in solution. • Indirect determination of sulfur monitoring the molecular absorbance of the CS • Direct analysis of diesel samples using a dilution in propan-1-ol.

  15. Direct olive oil analysis

    Directory of Open Access Journals (Sweden)

    Peña, F.

    2002-03-01

    Full Text Available The practical impact of “direct analysis” is undeniable as it strong contributes to enhance the so-called productive analytical features such as expeditiousness, reduction of costs and minimisation of risks for the analysts and environment. The main objective is to establish a reliable bypass to the conventional preliminary operations of the analytical process. This paper offers a systematic approach in this context and emphasises the great field of action of direct methodologies in the routine analysis of olive oil. Two main types of methodologies are considered. On the one hand, the direct determination of volatile components is systematically considered. On the other hand, simple procedures to automatically implement the preliminary operations of the oil analysis using simple devices in which the sample is directly introduced with/without a simple dilution are present and discussed.El impacto práctico del análisis directo es tan innegable como que el contribuye decisivamente a mejorar las denominadas características analíticas relacionadas con la productividad como la rapidez, la reducción de costes y la minimización de riesgos para los analistas y el ambiente. El principal objetivo es establecer un adecuado "bypass" a las operaciones convencionales preliminares del proceso analítico. Este artículo ofrece una propuesta sistemática en este contexto y resalta el gran campo de acción de las metodologías directas en los análisis de rutina del aceite de oliva. Se analizan los dos tipos principales de metodologías. Por una lado, se analiza la determinación directa de los compuestos volátiles. Por el otro, se presentan y discuten los procedimientos simples para implementar automáticamente las operaciones preliminares del análisis del aceite usando sistemas simples en los que la muestra se introduce directamente con/sin un dilución simple.

  16. Chemical analysis report 2014

    International Nuclear Information System (INIS)

    Elbouzidi, Saliha; Elyahyaoui, Adil; Ghassan, Acil; Marah, Hamid

    2014-01-01

    This report highlights the results of chemical analyzes related to Major elements, traces and heavy metals carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 120 samples. The report presents the analytical techniques used (parameters and methods), a legend and the results tables.

  17. Chemical analysis report 2015

    International Nuclear Information System (INIS)

    2015-01-01

    This report highlights the results of chemical analyzes of fluorides, bromides, lithium and boron carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 120 samples. The report presents the analytical techniques used (parameters and methods), a legend and the results tables.

  18. Chemical reactions directed Peptide self-assembly.

    Science.gov (United States)

    Rasale, Dnyaneshwar B; Das, Apurba K

    2015-05-13

    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly.

  19. Substrate-Directed Catalytic Selective Chemical Reactions.

    Science.gov (United States)

    Sawano, Takahiro; Yamamoto, Hisashi

    2018-05-04

    The development of highly efficient reactions at only the desired position is one of the most important subjects in organic chemistry. Most of the reactions in current organic chemistry are reagent- or catalyst-controlled reactions, and the regio- and stereoselectivity of the reactions are determined by the inherent nature of the reagent or catalyst. In sharp contrast, substrate-directed reaction determines the selectivity of the reactions by the functional group on the substrate and can strictly distinguish sterically and electronically similar multiple reaction sites in the substrate. In this Perspective, three topics of substrate-directed reaction are mainly reviewed: (1) directing group-assisted epoxidation of alkenes, (2) ring-opening reactions of epoxides by various nucleophiles, and (3) catalytic peptide synthesis. Our newly developed synthetic methods with new ligands including hydroxamic acid derived ligands realized not only highly efficient reactions but also pinpointed reactions at the expected position, demonstrating the substrate-directed reaction as a powerful method to achieve the desired regio- and stereoselective functionalization of molecules from different viewpoints of reagent- or catalyst-controlled reactions.

  20. Chemical substructure analysis in toxicology

    Energy Technology Data Exchange (ETDEWEB)

    Beauchamp, R.O. Jr. [Center for Information on Toxicology and Environment, Raleigh, NC (United States)

    1990-12-31

    A preliminary examination of chemical-substructure analysis (CSA) demonstrates the effective use of the Chemical Abstracts compound connectivity file in conjunction with the bibliographic file for relating chemical structures to biological activity. The importance of considering the role of metabolic intermediates under a variety of conditions is illustrated, suggesting structures that should be examined that may exhibit potential activity. This CSA technique, which utilizes existing large files accessible with online personal computers, is recommended for use as another tool in examining chemicals in drugs. 2 refs., 4 figs.

  1. Chemical Analysis Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Uses state-of-the-art instrumentation for qualitative and quantitative analysis of organic and inorganic compounds, and biomolecules from gas, liquid, and...

  2. Microprocessors in automatic chemical analysis

    International Nuclear Information System (INIS)

    Goujon de Beauvivier, M.; Perez, J.-J.

    1979-01-01

    Application of microprocessors to programming and computing of solutions chemical analysis by a sequential technique is examined. Safety, performances reliability are compared to other methods. An example is given on uranium titration by spectrophotometry [fr

  3. Utilization of chemical derivatives in activation analysis

    International Nuclear Information System (INIS)

    Ehmann, W.D.

    1990-01-01

    Derivative activation analysis (DAA) is a method to enhance the sensitivity of nuclear activation analysis for the more elusive elements. It may also allow a degree of chemical speciation for the element of interest. DAA uses a preirradiation chemical reaction on the sample to initiate the formation of, or an exchange with, a chemical complex which contains a surrogate element, M. As a result, the amount of the element or the chemical species to be determined, X, is now represented by measurement of the amount of the surrogate element, M, that is made part of, or released by the complex species. The surrogate element is selected for its superior properties for nuclear activation analysis and the absence of interference reaction in its final determination by instrumental neutron activation analysis (INAA) after some preconcentration or separation chemistry. Published DAA studies have been limited to neutron activation analysis. DAA can offer the analyst some important advantages. It can determine elements, functional groups, or chemical species which cannot be determined directly by INAA, fast neutron activation analysis (FNAA), prompt gamma neutron activation analysis (PGNAA), or charged particle activation analysis (CPAA) procedures. When compared with conventional RNAA, there are fewer precautions with respect to handling of intensely radioactive samples, since the chemistry is done before the irradiation. The preirradiation chemistry may also eliminate many interferences that might occur in INAA and, through use of an appropriate surrogate element, can place the analytical gamma-ray line in an interference-free region of the gamma-ray spectrum

  4. Direct Push Chemical Sensors for DNAPL

    Science.gov (United States)

    2007-01-01

    System Improvements Problem Solution 1. Insufficient thermal protection Implemented use of microporous insulation . Lab and field tests have shown...screw thread cap with Teflon lined septum. The soil and methanol were mixed by hand and the vial was placed in an insulated cooler on ice until...Teflon lined septum. The vials were stored within an insulated cooler on ice until shipped to Columbia Analytical Services for analysis by U.S. EPA

  5. Trace Chemical Analysis Methodology

    Science.gov (United States)

    1980-04-01

    147 65 Modified DR/2 spectrophotometer face ........... ... 150 66 Colorimetric oil analysis field test kit ......... .. 152 67 Pictorial step...Assisted Pattern Recognitio Perhaps the most promising application of pattern recogntiontechniques for this research effort is the elucidation ".f the...large compartment on the spectrophotomer face . The screwdriver is used to adjust the zero adjust and light ad- just knobs, and the stainless steel

  6. Droplet heat transfer and chemical reactions during direct containment heating

    International Nuclear Information System (INIS)

    Baker, L. Jr.

    1986-01-01

    A simplified model of heat transfer and chemical reaction has been adapted to evaluate the expected behavior of droplets containing unreacted Zircaloy and stainless steel moving through the containment atmosphere during postulated accidents involving direct containment heating. The model includes internal and external diffusive resistances to reaction. The results indicate that reactions will be incomplete for many conditions characteristic of direct containment heating sequences

  7. Systems analysis of past, present, and future chemical terrorism scenarios.

    Energy Technology Data Exchange (ETDEWEB)

    Hoette, Trisha Marie

    2012-03-01

    Throughout history, as new chemical threats arose, strategies for the defense against chemical attacks have also evolved. As a part of an Early Career Laboratory Directed Research and Development project, a systems analysis of past, present, and future chemical terrorism scenarios was performed to understand how the chemical threats and attack strategies change over time. For the analysis, the difficulty in executing chemical attack was evaluated within a framework of three major scenario elements. First, historical examples of chemical terrorism were examined to determine how the use of chemical threats, versus other weapons, contributed to the successful execution of the attack. Using the same framework, the future of chemical terrorism was assessed with respect to the impact of globalization and new technologies. Finally, the efficacy of the current defenses against contemporary chemical terrorism was considered briefly. The results of this analysis justify the need for continued diligence in chemical defense.

  8. Application of headspace and direct immersion solid-phase microextraction in the analysis of organothiophosphates related to the Chemical Weapons Convention from water and complex matrices.

    Science.gov (United States)

    Althoff, Marc André; Bertsch, Andreas; Metzulat, Manfred; Klapötke, Thomas M; Karaghiosoff, Konstantin L

    2017-11-01

    The successful application of headspace (HS) and direct immersion (DI) solid phase microextraction (SPME) for the unambiguous identification and characterization of a series of toxic thiophosphate esters, such as Amiton (I), from aqueous phases and complex matrices (e.g. grass and foliage) has been demonstrated. A Thermo Scientific gas chromatograph (GC) - tandem mass spectrometer (MS/MS) system with a TriPlus RSH® autosampler and a SPME tool was used to investigate the effect of different parameters that influence the extraction efficiency: e.g. pH of the sample matrix and extraction temperature. The developed methods were employed for the detection of several Amiton derivatives (Schedule II of the CWC) that are structurally closely related to each other; some of which are new and have not been reported in literature previously. In addition, a novel DI SPME method from complex matrices for the analysis of organophosphates related to the CWC was developed. The studies clearly show that DI SPME for complex matrices is superior to HS extraction and can potentially be applied to other related compounds controlled under the CWC. Copyright © 2017. Published by Elsevier B.V.

  9. Chemical analysis of geological samples

    International Nuclear Information System (INIS)

    Malhotra, R.K.

    1997-01-01

    Most of the analytical methodology used in geochemical exploration has been based on molecular absorption, atomic absorption, and ICP-AES, ICPMAS etc. Detection limit and precision are factors in the choice of methodology in search of metallic ores and are related to the accuracy of data. A brief outline of the various chemical analysis techniques explaining essentially the basics of measurement principles and instrumentation is discussed

  10. Calibrating Detailed Chemical Analysis of M dwarfs

    Science.gov (United States)

    Veyette, Mark; Muirhead, Philip Steven; Mann, Andrew; Brewer, John; Allard, France; Homeier, Derek

    2018-01-01

    The ability to perform detailed chemical analysis of Sun-like F-, G-, and K-type stars is a powerful tool with many applications including studying the chemical evolution of the Galaxy, assessing membership in stellar kinematic groups, and constraining planet formation theories. Unfortunately, complications in modeling cooler stellar atmospheres has hindered similar analysis of M-dwarf stars. Large surveys of FGK abundances play an important role in developing methods to measure the compositions of M dwarfs by providing benchmark FGK stars that have widely-separated M dwarf companions. These systems allow us to empirically calibrate metallicity-sensitive features in M dwarf spectra. However, current methods to measure metallicity in M dwarfs from moderate-resolution spectra are limited to measuring overall metallicity and largely rely on astrophysical abundance correlations in stellar populations. In this talk, I will discuss how large, homogeneous catalogs of precise FGK abundances are crucial to advancing chemical analysis of M dwarfs beyond overall metallicity to direct measurements of individual elemental abundances. I will present a new method to analyze high-resolution, NIR spectra of M dwarfs that employs an empirical calibration of synthetic M dwarf spectra to infer effective temperature, Fe abundance, and Ti abundance. This work is a step toward detailed chemical analysis of M dwarfs at a similar precision achieved for FGK stars.

  11. Rapid chemical analysis of allanite

    International Nuclear Information System (INIS)

    Nishiyama, Goro; Hayashi, Hiroshi

    1981-01-01

    Rapid chemical analysis of allanite was studied by atomic absorption spectrophotometry. Powdered sample was fused with mixture of sodium carbonate anhydrous and borax (4 : 1 weight) in platinum crucible and sample solution was prepared. SiO 2 , Fe 2 O 3 , Al 2 O 3 , MnO and rare earth metals were determined by atomic absorption spectrophotometry, CaO, MgO and Ce 2 O 3 by titration, ThO 2 by colorimetry, and La 2 O 3 by flame photometry respectively. For sample solution treated with hydrofluoric acid and sulfuric acid. Na 2 O and K 2 O were determined by atomic absorption spectrophotometry, TiO 2 and P 2 O 5 by colorimetry. Chemical analyses for four samples were carried out and gave consistent results. (author)

  12. An extended chemical analysis of gallstone

    OpenAIRE

    Chandran, P.; Kuchhal, N. K.; Garg, P.; Pundir, C. S.

    2007-01-01

    Chemical composition of gall stones is essential for aetiopathogensis of gallstone disease. We have reported quantitative chemical analysis of total cholesterol bilirubin, calcium, iron and inorganic phosphate in 120 gallstones from haryana. To extend this chemical analysis of gall stones by studying more cases and by analyzing more chemical constituents. A quantitative chemical analysis of total cholesterol, total bilirubin, fatty acids, triglycerides, phospholipids, bile acids, soluble prot...

  13. Chemical compound-based direct reprogramming for future clinical applications

    Science.gov (United States)

    Takeda, Yukimasa; Harada, Yoshinori; Yoshikawa, Toshikazu; Dai, Ping

    2018-01-01

    Recent studies have revealed that a combination of chemical compounds enables direct reprogramming from one somatic cell type into another without the use of transgenes by regulating cellular signaling pathways and epigenetic modifications. The generation of induced pluripotent stem (iPS) cells generally requires virus vector-mediated expression of multiple transcription factors, which might disrupt genomic integrity and proper cell functions. The direct reprogramming is a promising alternative to rapidly prepare different cell types by bypassing the pluripotent state. Because the strategy also depends on forced expression of exogenous lineage-specific transcription factors, the direct reprogramming in a chemical compound-based manner is an ideal approach to further reduce the risk for tumorigenesis. So far, a number of reported research efforts have revealed that combinations of chemical compounds and cell-type specific medium transdifferentiate somatic cells into desired cell types including neuronal cells, glial cells, neural stem cells, brown adipocytes, cardiomyocytes, somatic progenitor cells, and pluripotent stem cells. These desired cells rapidly converted from patient-derived autologous fibroblasts can be applied for their own transplantation therapy to avoid immune rejection. However, complete chemical compound-induced conversions remain challenging particularly in adult human-derived fibroblasts compared with mouse embryonic fibroblasts (MEFs). This review summarizes up-to-date progress in each specific cell type and discusses prospects for future clinical application toward cell transplantation therapy. PMID:29739872

  14. Chemical analysis as production guide

    International Nuclear Information System (INIS)

    Bouzigues, H.; Fontaine, A.; Patigny, P.

    1975-01-01

    All piloting data of chemical processing plants are based on the results of analysis. The first part of this article describes a system of analysers adapted to the needs of the Pierrelatte plant, with management of signals collected by the factory computer. Part two shows the influence of analytical development in the establishment of material balance sheets for the Marcoule spent fuel processing plant. Part three stresses the contribution of the automation of analytical test processes at the La Hague spent fuel processing plant. In all three cases the progress in analytical methods greatly improves the safety, reliability and response time of the various operations [fr

  15. A near-infrared reflectance spectroscopic method for the direct analysis of several fodder-related chemical components in drumstick (Moringa oleifera Lam.) leaves.

    Science.gov (United States)

    Zhang, Junjie; Li, Shuqi; Lin, Mengfei; Yang, Endian; Chen, Xiaoyang

    2018-05-01

    The drumstick tree has traditionally been used as foodstuff and fodder in several countries. Due to its high nutritional value and good biomass production, interest in this plant has increased in recent years. It has therefore become important to rapidly and accurately evaluate drumstick quality. In this study, we addressed the optimization of Near-infrared spectroscopy (NIRS) to analyze crude protein, crude fat, crude fiber, iron (Fe), and potassium (K) in a variety of drumstick accessions (N = 111) representing different populations, cultivation programs, and climates. Partial least-squares regression with internal cross-validation was used to evaluate the models and identify possible spectral outliers. The calibration statistics for these fodder-related chemical components suggest that NIRS can predict these parameters in a wide range of drumstick types with high accuracy. The NIRS calibration models developed in this study will be useful in predicting drumstick forage quality for these five quality parameters.

  16. Chemical analysis by nuclear techniques

    International Nuclear Information System (INIS)

    Sohn, S. C.; Kim, W. H.; Park, Y. J.; Park, Y. J.; Song, B. C.; Jeon, Y. S.; Jee, K. Y.; Pyo, H. Y.

    2002-01-01

    This state art report consists of four parts, production of micro-particles, analysis of boron, alpha tracking method and development of neutron induced prompt gamma ray spectroscopy (NIPS) system. The various methods for the production of micro-paticles such as mechanical method, electrolysis method, chemical method, spray method were described in the first part. The second part contains sample treatment, separation and concentration, analytical method, and application of boron analysis. The third part contains characteristics of alpha track, track dectectors, pretreatment of sample, neutron irradiation, etching conditions for various detectors, observation of track on the detector, etc. The last part contains basic theory, neutron source, collimator, neutron shields, calibration of NIPS, and application of NIPS system

  17. Chemical analysis by nuclear techniques

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, S. C.; Kim, W. H.; Park, Y. J.; Song, B. C.; Jeon, Y. S.; Jee, K. Y.; Pyo, H. Y

    2002-01-01

    This state art report consists of four parts, production of micro-particles, analysis of boron, alpha tracking method and development of neutron induced prompt gamma ray spectroscopy (NIPS) system. The various methods for the production of micro-paticles such as mechanical method, electrolysis method, chemical method, spray method were described in the first part. The second part contains sample treatment, separation and concentration, analytical method, and application of boron analysis. The third part contains characteristics of alpha track, track dectectors, pretreatment of sample, neutron irradiation, etching conditions for various detectors, observation of track on the detector, etc. The last part contains basic theory, neutron source, collimator, neutron shields, calibration of NIPS, and application of NIPS system.

  18. Direct chemical-analysis of uv laser-ablation products of organic polymers by using selective ion monitoring mode in gas-chromatography mass-spectrometry

    Science.gov (United States)

    Cho, Yirang; Lee, H.W.; Fountain, S.T.; Lubman, D.M.

    1994-01-01

    Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the laser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in analyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers.

  19. Direct measurements of intermolecular forces by chemical force microscopy

    Science.gov (United States)

    Vezenov, Dmitri Vitalievich

    1999-12-01

    Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the

  20. Subfemtosecond directional control of chemical processes in molecules

    Science.gov (United States)

    Alnaser, Ali S.; Litvinyuk, Igor V.

    2017-02-01

    Laser pulses with a waveform-controlled electric field and broken inversion symmetry establish the opportunity to achieve directional control of molecular processes on a subfemtosecond timescale. Several techniques could be used to break the inversion symmetry of an electric field. The most common ones include combining a fundamental laser frequency with its second harmonic or with higher -frequency pulses (or pulse trains) as well as using few-cycle pulses with known carrier-envelope phase (CEP). In the case of CEP, control over chemical transformations, typically occurring on a timescale of many femtoseconds, is driven by much faster sub-cycle processes of subfemtosecond to few-femtosecond duration. This is possible because electrons are much lighter than nuclei and fast electron motion is coupled to the much slower nuclear motion. The control originates from populating coherent superpositions of different electronic or vibrational states with relative phases that are dependent on the CEP or phase offset between components of a two-color pulse. In this paper, we review the recent progress made in the directional control over chemical processes, driven by intense few-cycle laser pulses a of waveform-tailored electric field, in different molecules.

  1. New approach for direct chemical synthesis of hexagonal Co nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Frank M., E-mail: fabel@udel.edu [Physics and Astronomy, University of Delaware (United States); Tzitzios, Vasilis [Institute of Nanoscience and Nanotechnology, NCSR, Demokritos (Greece); Hadjipanayis, George C. [Physics and Astronomy, University of Delaware (United States)

    2016-02-15

    In this paper, we explore the possibility of producing hexagonal Cobalt nanoparticles, with high saturation magnetization by direct chemical synthesis. The nanoparticles were synthesized by reduction of anhydrous cobalt (II) chloride by NaBH{sub 4} in tetraglyme at temperatures in the range of 200–270 °C under a nitrogen–hydrogen atmosphere. The reactions were done at high temperatures to allow for the formation of as-made hexagonal cobalt. The size of the particles was controlled by the addition of different surfactants. The best magnetic properties so far were obtained on spherical hexagonal Co nanoparticles with an average size of 45 nm, a saturation magnetization of 143 emu/g and coercivity of 500 Oe. the saturation magnetization and coercivity were further improved by annealing the Co nanoparticles leading to saturation magnetization of 160 emu/g and coercivity of 540 Oe. - Highlights: • We synthesized hexagonal cobalt nanoparticles by a new wet chemical method. • We considered the effects of different surfactants on particles magnetic properties. • The as-made Co nanoparticles had magnetic properties of 143 emu/g and 500 Oe. • After annealing magnetic properties of 160 emu/g and 540 Oe were obtained.

  2. Delay chemical master equation: direct and closed-form solutions.

    Science.gov (United States)

    Leier, Andre; Marquez-Lago, Tatiana T

    2015-07-08

    The stochastic simulation algorithm (SSA) describes the time evolution of a discrete nonlinear Markov process. This stochastic process has a probability density function that is the solution of a differential equation, commonly known as the chemical master equation (CME) or forward-Kolmogorov equation. In the same way that the CME gives rise to the SSA, and trajectories of the latter are exact with respect to the former, trajectories obtained from a delay SSA are exact representations of the underlying delay CME (DCME). However, in contrast to the CME, no closed-form solutions have so far been derived for any kind of DCME. In this paper, we describe for the first time direct and closed solutions of the DCME for simple reaction schemes, such as a single-delayed unimolecular reaction as well as chemical reactions for transcription and translation with delayed mRNA maturation. We also discuss the conditions that have to be met such that such solutions can be derived.

  3. Direct single-molecule dynamic detection of chemical reactions.

    Science.gov (United States)

    Guan, Jianxin; Jia, Chuancheng; Li, Yanwei; Liu, Zitong; Wang, Jinying; Yang, Zhongyue; Gu, Chunhui; Su, Dingkai; Houk, Kendall N; Zhang, Deqing; Guo, Xuefeng

    2018-02-01

    Single-molecule detection can reveal time trajectories and reaction pathways of individual intermediates/transition states in chemical reactions and biological processes, which is of fundamental importance to elucidate their intrinsic mechanisms. We present a reliable, label-free single-molecule approach that allows us to directly explore the dynamic process of basic chemical reactions at the single-event level by using stable graphene-molecule single-molecule junctions. These junctions are constructed by covalently connecting a single molecule with a 9-fluorenone center to nanogapped graphene electrodes. For the first time, real-time single-molecule electrical measurements unambiguously show reproducible large-amplitude two-level fluctuations that are highly dependent on solvent environments in a nucleophilic addition reaction of hydroxylamine to a carbonyl group. Both theoretical simulations and ensemble experiments prove that this observation originates from the reversible transition between the reactant and a new intermediate state within a time scale of a few microseconds. These investigations open up a new route that is able to be immediately applied to probe fast single-molecule physics or biophysics with high time resolution, making an important contribution to broad fields beyond reaction chemistry.

  4. The modelling of direct chemical kinetic effects in turbulent flames

    Energy Technology Data Exchange (ETDEWEB)

    Lindstet, R.P. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Mechanical Engineering

    2000-06-01

    Combustion chemistry-related effects have traditionally been of secondary importance in the design of gas turbine combustors. However, the need to deal with issues such as flame stability, relight and pollutant emissions has served to bring chemical kinetics and the coupling of finite rate chemistry with turbulent flow fields to the centre of combustor design. Indeed, improved cycle efficiency and more stringent environmental legislation, as defined by the ICAO, are current key motivators in combustor design. Furthermore, lean premixed prevaporized (LPP) combustion systems, increasingly used for power generation, often operate close to the lean blow-off limit and are prone to extinction/reignition type phenomena. Thus, current key design issues require that direct chemical kinetic effects be accounted for accurately in any simulation procedure. The transported probability density function (PDF) approach uniquely offers the potential of facilitating the accurate modelling of such effects. The present paper thus assesses the ability of this technique to model kinetically controlled phenomena, such as carbon monoxide emissions and flame blow-off, through the application of a transported PDF method closed at the joint scalar level. The closure for the velocity field is at the second moment level, and a key feature of the present work is the use of comprehensive chemical kinetic mechanisms. The latter are derived from recent work by Lindstedt and co-workers that has resulted in a compact 141 reactions and 28 species mechanism for LNG combustion. The systematically reduced form used here features 14 independent C/H/O scalars, with the remaining species incorporated via steady state approximations. Computations have been performed for hydrogen/carbon dioxide and methane flames. The former (high Reynolds number) flames permit an assessment of the modelling of flame blow-off, and the methane flame has been selected to obtain an indication of the influence of differential

  5. Self-directed questions to improve students' ability in solving chemical problems

    Science.gov (United States)

    Sanjaya, Rahmat Eko; Muna, Khairiatul; Suharto, Bambang; Syahmani

    2017-12-01

    Students' ability in solving chemical problems is seen from their ability to solve chemicals' non-routine problems. It is due to learning faced directly on non-routine problems will generate a meaningful learning for students. Observations in Banjarmasin Public High School 1 (SMA Negeri 1 Banjarmasin) showed that students did not give the expected results when they were given the non-routine problems. Learning activities by emphasizing problem solving was implemented based on the existence of knowledge about cognition and regulation of cognition. Both of these elements are components of metacognition. The self-directed question is a strategy that involves metacognition in solving chemical problems. This research was carried out using classroom action research design in two cycles. Each cycle consists of four stages: planning, action, observation and reflection. The subjects were 34 students of grade XI-4 at majoring science (IPA) of SMA Negeri 1 Banjarmasin. The data were collected using tests of the students' ability in problem solving and non-tests instrument to know the process of implementation of the actions. Data were analyzed with descriptivequantitativeand qualitative analysis. The ability of students in solving chemical problems has increased from an average of 37.96 in cycle I became 61.83 in cycle II. Students' ability to solve chemical problems is viewed based on their ability to answer self-directed questions. Students' ability in comprehension questions increased from 73.04 in the cycle I became 96.32 in cycle II. Connection and strategic questions increased from 54.17 and 16.50 on cycle I became 63.73 and 55.23 on cycle II respectively. In cycle I, reflection questions were 26.96 and elevated into 36.27 in cycle II. The self-directed questions have the ability to help students to solve chemical problems through metacognition questions. Those questions guide students to find solutions in solving chemical problems.

  6. Molecular activation analysis for chemical speciation studies

    International Nuclear Information System (INIS)

    Chai-Chifang

    1998-01-01

    The term of Molecular Activation Analysis (MAA) refers to an activation analysis method that is able to provide information about the chemical species of elements in system of interests, though its definition has remained to be assigned. Its development is strongly stimulated by the urgent need to know the chemical species of elements, because the total concentrations are often without any meaning when assessing health or environmental risks of trace elements.In practice, the MAA is a combination of conventional instrumental or radiochemical activation analysis and physical, chemical or biochemical separation techniques. The MAA is able to play a particular role in speciation studies. However, the critical point in the MAA is that it is not permitted to change the primitive chemical species of elements in systems, or the change has to be under control; in the meantime it is not allowed to form the 'new artifact' originally not present in systems. Some practical examples of MAA for chemical species research performed recently in our laboratory will be presented as follows: Chemical species of platinum group elements in sediment; Chemical species of iodine in marine algae; Chemical species of mercury in human tissues; Chemical species of selenium in corn; Chemical species of rare earth elements in natural plant, etc. The merits and limitations of MAA will be described as well. (author)

  7. Direct-push geochemical profiling for assessment of inorganic chemical heterogeneity in aquifers

    Science.gov (United States)

    Schulmeister, M.K.; Healey, J.M.; Butler, J.J.; McCall, G.W.

    2004-01-01

    Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO3, Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors. ?? 2003 Elsevier B.V. All rights reserved.

  8. Chemical analysis of the Fornax Dwarf galaxy

    NARCIS (Netherlands)

    Letarte, Bruno

    2007-01-01

    This thesis is entitled “Chemical Analysis of the Fornax Dwarf Galaxy”, and it’s main goal is to determine what are the chemical elements present in the stars of this galaxy in order to try and understand it’s evolution. Galaxies are not “static” objects, they move, form stars and can interact with

  9. Chemical analysis of reactor and commercial columbium

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    The methods cover the chemical analysis of reactor and commercial columbium having chemical compositions within specified limits. The following analytical procedures are discussed along with apparatus, reagents, photometric practice, safety precautions, sampling, and rounding calculated values: nitrogen, by distillation (photometric) method; molybdenum and tungsten by the dithiol (photometric) method; iron by the 1,10-phenanthroline (photometric) method

  10. Physical controls on directed virus assembly at nanoscale chemical templates

    International Nuclear Information System (INIS)

    Cheung, C L; Chung, S; Chatterji, A; Lin, T; Johnson, J E; Hok, S; Perkins, J; De Yoreo, J

    2006-01-01

    Viruses are attractive building blocks for nanoscale heterostructures, but little is understood about the physical principles governing their directed assembly. In-situ force microscopy was used to investigate organization of Cowpea Mosaic Virus engineered to bind specifically and reversibly at nanoscale chemical templates with sub-30nm features. Morphological evolution and assembly kinetics were measured as virus flux and inter-viral potential were varied. The resulting morphologies were similar to those of atomic-scale epitaxial systems, but the underlying thermodynamics was analogous to that of colloidal systems in confined geometries. The 1D templates biased the location of initial cluster formation, introduced asymmetric sticking probabilities, and drove 1D and 2D condensation at subcritical volume fractions. The growth kinetics followed a t 1/2 law controlled by the slow diffusion of viruses. The lateral expansion of virus clusters that initially form on the 1D templates following introduction of polyethylene glycol (PEG) into the solution suggests a significant role for weak interaction

  11. Optical MEMS for chemical analysis and biomedicine

    CERN Document Server

    Jiang, Hongrui

    2016-01-01

    This book describes the current state of optical MEMS in chemical and biomedical analysis and brings together current trends and highlights topics representing the most exciting progress in recent years in the field.

  12. Chemical analysis of water in hydrogeology

    International Nuclear Information System (INIS)

    Flakova, R.; Zenisova, Z.; Seman, M.

    2010-01-01

    The aim of the monograph is to give complete information on the chemical analysis of water hydrogeology not only for the students program of Geology study (Bachelor degree study), Engineering Geology and Hydrogeology (Master's degree study) and Engineering Geology (doctoral level study), but also for students from other colleges and universities schools in Slovakia, as well as in the Czech Republic, dealing with the chemical composition of water and its quality, from different perspectives. The benefit would be for professionals with hydrogeological, water and environmental practices, who can find there all the necessary information about proper water sampling, the units used in the chemical analysis of water, expressing the proper chemical composition of water in its various parameters through classification of chemical composition of the water up to the basic features of physical chemistry at thermodynamic calculations and hydrogeochemical modelling.

  13. Artificial specific binders directly recovered from chemically modified nucleic acid libraries.

    Science.gov (United States)

    Kasahara, Yuuya; Kuwahara, Masayasu

    2012-01-01

    Specific binders comprised of nucleic acids, that is, RNA/DNA aptamers, are attractive functional biopolymers owing to their potential broad application in medicine, food hygiene, environmental analysis, and biological research. Despite the large number of reports on selection of natural DNA/RNA aptamers, there are not many examples of direct screening of chemically modified nucleic acid aptamers. This is because of (i) the inferior efficiency and accuracy of polymerase reactions involving transcription/reverse-transcription of modified nucleotides compared with those of natural nucleotides, (ii) technical difficulties and additional time and effort required when using modified nucleic acid libraries, and (iii) ambiguous efficacies of chemical modifications in binding properties until recently; in contrast, the effects of chemical modifications on biostability are well studied using various nucleotide analogs. Although reports on the direct screening of a modified nucleic acid library remain in the minority, chemical modifications would be essential when further functional expansion of nucleic acid aptamers, in particular for medical and biological uses, is considered. This paper focuses on enzymatic production of chemically modified nucleic acids and their application to random screenings. In addition, recent advances and possible future research are also described.

  14. Artificial Specific Binders Directly Recovered from Chemically Modified Nucleic Acid Libraries

    Directory of Open Access Journals (Sweden)

    Yuuya Kasahara

    2012-01-01

    Full Text Available Specific binders comprised of nucleic acids, that is, RNA/DNA aptamers, are attractive functional biopolymers owing to their potential broad application in medicine, food hygiene, environmental analysis, and biological research. Despite the large number of reports on selection of natural DNA/RNA aptamers, there are not many examples of direct screening of chemically modified nucleic acid aptamers. This is because of (i the inferior efficiency and accuracy of polymerase reactions involving transcription/reverse-transcription of modified nucleotides compared with those of natural nucleotides, (ii technical difficulties and additional time and effort required when using modified nucleic acid libraries, and (iii ambiguous efficacies of chemical modifications in binding properties until recently; in contrast, the effects of chemical modifications on biostability are well studied using various nucleotide analogs. Although reports on the direct screening of a modified nucleic acid library remain in the minority, chemical modifications would be essential when further functional expansion of nucleic acid aptamers, in particular for medical and biological uses, is considered. This paper focuses on enzymatic production of chemically modified nucleic acids and their application to random screenings. In addition, recent advances and possible future research are also described.

  15. Chemical methods of rock analysis

    National Research Council Canada - National Science Library

    Jeffery, P. G; Hutchison, D

    1981-01-01

    A practical guide to the methods in general use for the complete analysis of silicate rock material and for the determination of all those elements present in major, minor or trace amounts in silicate...

  16. Chemical analysis of steel by optical emission spectrometry

    International Nuclear Information System (INIS)

    Hayakawa, M.O.; Kajita, T.; Jeszensky, G.

    1981-01-01

    The development of the chemical analysis for special steels by optical emission spectrometry direct reading method with computer, at the Siderurgica N.S. Aparecida S.A. is presented. Results are presented for the low alloy steels and high speed steel. Also, the contribution of this method to the special steel preparation is commented. (Author) [pt

  17. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor); Lane, Arthur L. (Inventor)

    2018-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  18. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    1993-03-01

    The Sub-Committee on Chemical Analysis of Graphite was organized in April 1989, under the Committee on Chemical Analysis of Nuclear Fuels and Reactor Materials, JAERI. The Sub-Committee carried out collaborative analyses among eleven participating laboratories for the certification of the Certified Reference Materials (CRMs), JAERI-G5 and G6, after developing and evaluating analytical methods during the period of September 1989 to March 1992. The certified values were given for ash, boron and silicon in the CRM based on the collaborative analysis. The values for ten elements (Al, Ca, Cr, Fe, Mg, Mo, Ni, Sr, Ti, V) were not certified, but given for information. Preparation, homogeneity testing and chemical analyses for certification of reference materials were described in this paper. (author) 52 refs

  19. An analysis of multislot directional coupler

    International Nuclear Information System (INIS)

    Arai, Hiroyuki; Goto, Naohisa; Yamamoto, Takumi.

    1986-03-01

    This paper presents an analysis of multislot directional coupler for monitoring the gyrotron output. We solved the boundary value problem of the directional coupler to investigate the detailed effect of finite thickness slot and mutual coupling between slots. Numerical data of coupler design is presented for non-resonant a pair slot, and mode sensitivity in overmoded waveguide is also evaluated. (author)

  20. Molecular activation analysis for chemical species studies

    International Nuclear Information System (INIS)

    Chai Zhifang; Mao Xueying; Wang Yuqi; Sun Jingxin; Qian Qingfang; Hou Xiaolin; Zhang Peiqun; Chen Chunying; Feng Weiyu; Ding Wenjun; Li Xiaolin; Li Chunsheng; Dai Xiongxin

    2001-01-01

    The Molecular Activation Analysis (MAA) mainly refers to an activation analysis method that is able to provide information about the chemical species of elements in systems of interest, though its exact definition has remained to be assigned. Its development is strongly stimulated by the urgent need to know the chemical species of elements, because the bulk contents or concentrations are often insignificant for judging biological, environmental or geochemical effects of elements. In this paper, the features, methodology and limitation of MAA were outlined. Further, the up-to-date MAA progress made in our laboratory was introduced as well. (author)

  1. Service activities of chemical analysis division

    International Nuclear Information System (INIS)

    Eom, Tae Yoon; Suh, Moo Yul; Park, Kyoung Kyun; Jung, Ki Suk; Joe, Kih Soo; Jee, Kwang Yong; Jung, Woo Sik; Sohn, Se Chul; Yeo, In Heong; Han, Sun Ho

    1988-12-01

    Progress of the Division during the year of 1988 was described on the service activities for various R and D projects carrying out in the Institute, for the fuel fabrication and conversion plant, and for the post-irradiation examination facility. Relevant analytical methodologies developed for the chemical analysis of an irradiated fuel, safeguards chemical analysis, and pool water monitoring were included such as chromatographic separation of lanthanides, polarographic determination of dissolved oxygen in water, and automation on potentiometric titration of uranium. Some of the laboratory manuals revised were also included in this progress report. (Author)

  2. Chemical analysis by nuclear methods. v. 2

    International Nuclear Information System (INIS)

    Alfassi, Z.B.

    1998-01-01

    'Chemical analysis by Nuclear Methods' is an effort of some renowned authors in field of nuclear chemistry and radiochemistry which is compiled by Alfassi, Z.B. and translated into Farsi version collected in two volumes. The second volume consists of the following chapters: Detecting ion recoil scattering and elastic scattering are dealt in the eleventh chapter, the twelfth chapter is devoted to nuclear reaction analysis using charged particles, X-ray emission is discussed at thirteenth chapter, the fourteenth chapter is about using ion microprobes, X-ray fluorescence analysis is discussed in the fifteenth chapter, alpha, beta and gamma ray scattering in chemical analysis are dealt in chapter sixteen, Moessbauer spectroscopy and positron annihilation are discussed in chapter seventeen and eighteen; The last two chapters are about isotope dilution analysis and radioimmunoassay

  3. An extended chemical analysis of gallstone.

    Science.gov (United States)

    Chandran, P; Kuchhal, N K; Garg, P; Pundir, C S

    2007-09-01

    Chemical composition of gall stones is essential for aetiopathogensis of gallstone disease. We have reported quantitative chemical analysis of total cholesterol bilirubin, calcium, iron and inorganic phosphate in 120 gallstones from haryana. To extend this chemical analysis of gall stones by studying more cases and by analyzing more chemical constituents. A quantitative chemical analysis of total cholesterol, total bilirubin, fatty acids, triglycerides, phospholipids, bile acids, soluble proteins, sodium potassium, magnesium, copper, oxalate and chlorides of biliary calculi (52 cholesterol, 76 mixed and 72 pigment) retrieved from surgical operation of 200 patients from Haryana state was carried out. Total cholesterol as the major component and total bilirubin, phospholipids, triglycerides, bile acids, fatty acids (esterified), soluble protein, calcium, magnesium, iron, copper, sodium, potassium, inorganic phosphate, oxalate and chloride as minor components were found in all types of calculi. The cholesterol stones had higher content of total cholesterol, phospholipids, fatty acids (esterified), inorganic phosphate and copper compared to mixed and pigment stones. The mixed stones had higher content of iron and triglycerides than to cholesterol and pigment stones. The pigment stones were richer in total bilirubin, bile acids, calcium, oxalate, magnesium, sodium, potassium, chloride and soluble protein compared to cholesterol and mixed stones. Although total cholesterol was a major component of cholesterol, mixed and pigment gall stone in Haryana, the content of most of the other lipids, cations and anions was different in different gall stones indicating their different mechanism of formation.

  4. Direct action of endocrine disrupting chemicals on human sperm

    DEFF Research Database (Denmark)

    Schiffer, Christian; Müller, Astrid; Egeberg, Dorte L

    2014-01-01

    Synthetic endocrine disrupting chemicals (EDCs), omnipresent in food, household, and personal care products, have been implicated in adverse trends in human reproduction, including infertility and increasing demand for assisted reproduction. Here, we study the action of 96 ubiquitous EDCs on huma...

  5. Direct and indirect chemical defence of pine against folivorous insects

    NARCIS (Netherlands)

    Mumm, R.; Hilker, M.

    2006-01-01

    The chemical defence of pine against herbivorous insects has been intensively studied with respect to its effects on the performance and behaviour of the herbivores as well as on the natural enemies of pine herbivores. The huge variety of terpenoid pine components play a major role in mediating

  6. Chemical Reaction Engineering: Current Status and Future Directions.

    Science.gov (United States)

    Dudukovic, M. P.

    1987-01-01

    Describes Chemical Reaction Engineering (CRE) as the discipline that quantifies the interplay of transport phenomena and kinetics in relating reactor performance to operating conditions and input variables. Addresses the current status of CRE in both academic and industrial settings and outlines future trends. (TW)

  7. Direct chemical modification and voltammetric detection of glycans in glycoproteins

    Czech Academy of Sciences Publication Activity Database

    Trefulka, Mojmír; Paleček, Emil

    2014-01-01

    Roč. 48, NOV2014 (2014), s. 52-55 ISSN 1388-2481 R&D Projects: GA ČR(CZ) GAP301/11/2055 Institutional support: RVO:68081707 Keywords : Glycoproteins * Chemical modification * Os(VI)L complexes Subject RIV: BO - Biophysics Impact factor: 4.847, year: 2014

  8. Failure analysis on a chemical waste pipe

    International Nuclear Information System (INIS)

    Ambler, J.R.

    1985-01-01

    A failure analysis of a chemical waste pipe illustrates how nuclear technology can spin off metallurgical consultant services. The pipe, made of zirconium alloy (Zr-2.5 wt percent Nb, UNS 60705), had cracked in several places, all at butt welds. A combination of fractography and metallography indicated delayed hydride cracking

  9. Effect-directed analysis supporting monitoring of aquatic ...

    Science.gov (United States)

    Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone but tools are required to reduce this complexity and identify those chemicals that might cause adverse effects. Effect-directed analysis (EDA) is designed to meet this challenge and faces increasing interest in water and sediment quality monitoring. Thus, the present paper summarizes current experience with the EDA approach and the tools required,and provides practical advice on their application. The paper highlights the need for proper problem formulation and gives general advice for study design. As the EDA approach is directed by toxicity, basic principles for the selection of bioassays are given as well as a comprehensive compilation of appropriate assays, includingtheir strengths andweaknesses. A specific focus is given to strategies for sampling, extraction and bioassay dosing since they strongly impact prioritization of toxicants in EDA. Reduction of sample complexity mainly relies onfractionation procedures, which are discussed in this paper, including quality assurance and quality control. Automated combinations of fractionation, biotesting and chemical analysis using so-called hyphenated tools can enhance the throughput and might reduce the risk of artifacts in laboratory work. The key to determiningthe chemical structures causing effects is analytical toxi

  10. Computational singular perturbation analysis of stochastic chemical systems with stiffness

    Science.gov (United States)

    Wang, Lijin; Han, Xiaoying; Cao, Yanzhao; Najm, Habib N.

    2017-04-01

    Computational singular perturbation (CSP) is a useful method for analysis, reduction, and time integration of stiff ordinary differential equation systems. It has found dominant utility, in particular, in chemical reaction systems with a large range of time scales at continuum and deterministic level. On the other hand, CSP is not directly applicable to chemical reaction systems at micro or meso-scale, where stochasticity plays an non-negligible role and thus has to be taken into account. In this work we develop a novel stochastic computational singular perturbation (SCSP) analysis and time integration framework, and associated algorithm, that can be used to not only construct accurately and efficiently the numerical solutions to stiff stochastic chemical reaction systems, but also analyze the dynamics of the reduced stochastic reaction systems. The algorithm is illustrated by an application to a benchmark stochastic differential equation model, and numerical experiments are carried out to demonstrate the effectiveness of the construction.

  11. Probabilistic risk analysis in chemical engineering

    International Nuclear Information System (INIS)

    Schmalz, F.

    1991-01-01

    In risk analysis in the chemical industry, recognising potential risks is considered more important than assessing their quantitative extent. Even in assessing risks, emphasis is not on the probability involved but on the possible extent. Qualitative assessment has proved valuable here. Probabilistic methods are used in individual cases where the wide implications make it essential to be able to assess the reliability of safety precautions. In this case, assessment therefore centres on the reliability of technical systems and not on the extent of a chemical risk. 7 figs

  12. Microfabricated Gas Phase Chemical Analysis Systems

    International Nuclear Information System (INIS)

    FRYE-MASON, GREGORY CHARLES; HELLER, EDWIN J.; HIETALA, VINCENT M.; KOTTENSTETTE, RICHARD; LEWIS, PATRICK R.; MANGINELL, RONALD P.; MATZKE, CAROLYN M.; WONG, CHUNGNIN C.

    1999-01-01

    A portable, autonomous, hand-held chemical laboratory ((micro)ChemLab(trademark)) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described

  13. Direct-Dispense Polymeric Waveguides Platform for Optical Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Mohamad Hajj-Hassan

    2008-12-01

    Full Text Available We describe an automated robotic technique called direct-dispense to fabricate a polymeric platform that supports optical sensor arrays. Direct-dispense, which is a type of the emerging direct-write microfabrication techniques, uses fugitive organic inks in combination with cross-linkable polymers to create microfluidic channels and other microstructures. Specifically, we describe an application of direct-dispensing to develop optical biochemical sensors by fabricating planar ridge waveguides that support sol-gelderived xerogel-based thin films. The xerogel-based sensor materials act as host media to house luminophore biochemical recognition elements. As a prototype implementation, we demonstrate gaseous oxygen (O2 responsive optical sensors that operate on the basis of monitoring luminescence intensity signals. The optical sensor employs a Light Emitting Diode (LED excitation source and a standard silicon photodiode as the detector. The sensor operates over the full scale (0%-100% of O2 concentrations with a response time of less than 1 second. This work has implications for the development of miniaturized multisensor platforms that can be cost-effectively and reliably mass-produced.

  14. Spatial localisation of curcumin and rapid screening of the chemical compositions of turmeric rhizomes (Curcuma longa Linn.) using Direct Analysis in Real Time-Mass Spectrometry (DART-MS).

    Science.gov (United States)

    Rahman, A F M Motiur; Angawi, Rihab F; Kadi, Adnan A

    2015-04-15

    Curcumin is a potent antioxidant agent having versatile biological activities is present in turmeric rhizomes (Curcuma longa Linn.). Powder of turmeric rhizomes is consumes as curry spicy worldwide, especially in Asia. In this study, we demonstrate that, bioactive curcumin and its analog demethoxycurcumin are chiefly concentrated in the pith rather than the other parts of the turmeric rhizomes and it was discovered using modern atmospheric ionisation source 'Direct Analysis in Real Time' (DART) connected with an Ion Trap Mass Spectrometry. In addition, all the major components present in turmeric rhizomes were detected in positive and/or in negative ion mode using DART. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Chemical analysis quality assurance at the ICPP

    International Nuclear Information System (INIS)

    Hand, R.L.

    1990-01-01

    This document discusses the chemical analysis quality assurance program at the ICPP which involves records management, analytical methods quality control, analysis procedures and training and qualification. Since 1979, the major portion of the quality assurance program has been implemented on a central analytical computer system. The individual features provided by the system are storage, retrieval, and search capabilities over all general request and sample analysis information, automatic method selection for all process streams, automation of all method calculations, automatic assignment of bias and precision estimates at all analysis levels, with-method-use requalification, untrained or unqualified analyst method lockout, statistical testing of all process stream results for replicate agreement, automatic testing of process results against pre- established operating, safety, or failure limits at varying confidence levels, and automatic transfer and report of all analysis data plus all statistical testing to the Production Department

  16. Direct numerical simulation of turbulent, chemically reacting flows

    Science.gov (United States)

    Doom, Jeffrey Joseph

    This dissertation: (i) develops a novel numerical method for DNS/LES of compressible, turbulent reacting flows, (ii) performs several validation simulations, (iii) studies auto-ignition of a hydrogen vortex ring in air and (iv) studies a hydrogen/air turbulent diffusion flame. The numerical method is spatially non-dissipative, implicit and applicable over a range of Mach numbers. The compressible Navier-Stokes equations are rescaled so that the zero Mach number equations are discretely recovered in the limit of zero Mach number. The dependent variables are co--located in space, and thermodynamic variables are staggered from velocity in time. The algorithm discretely conserves kinetic energy in the incompressible, inviscid, non--reacting limit. The chemical source terms are implicit in time to allow for stiff chemical mechanisms. The algorithm is readily applicable to complex chemical mechanisms. Good results are obtained for validation simulations. The algorithm is used to study auto-ignition in laminar vortex rings. A nine species, nineteen reaction mechanism for H2/air combustion proposed by Mueller et al. [37] is used. Diluted H 2 at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratio, oxidizer temperature, Lewis number and stroke ratio (ratio of piston stroke length to diameter). Results show that auto--ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a 'most reactive' mixture fraction, zeta MR (Mastorakos et al. [32]). Subsequent evolution of the flame is not predicted by zetaMR; a most reactive temperature TMR is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke

  17. Direct analysis of quantal radiation response data

    International Nuclear Information System (INIS)

    Thames, H.D. Jr.; Rozell, M.E.; Tucker, S.L.; Ang, K.K.; Travis, E.L.; Fisher, D.R.

    1986-01-01

    A direct analysis is proposed for quantal (all-or-nothing) responses to fractionated radiation and endpoint-dilution assays of cell survival. As opposed to two-step methods such as the reciprocal-dose technique, in which ED 50 values are first estimated for different fractionation schemes and then fit (as reciprocals) against dose per fraction, all raw data are included in a single maximum-likelihood treatment. The method accommodates variations such as short-interval fractionation regimens designed to determine tissue repair kinetics, tissue response to continuous exposures, and data obtained using endpoint-dilution assays of cell survival after fractionated doses. Monte-Carlo techniques were used to compare the direct and reciprocal-dose methods for analysis of small-scale and large-scale studies of response to fractionated doses. Both methods tended toward biased estimates in the analysis of small-scale (3 fraction numbers) studies. The α/β ratios showed less scatter when estimated by the direct method. The 95% confidence intervals determined by the direct method were more appropriate than those determined by reciprocal-dose analysis, for which 18% (small-scale study) or 8% (large-scale study) of the confidence intervals did not include the 'true' value of α/β. (author)

  18. Chemical analysis of refractories by plasma spectrometry

    International Nuclear Information System (INIS)

    Coutinho, C.A.

    1990-01-01

    X-ray spectrometry has been, since the last two or three decades, the traditional procedure for the chemical analysis of refractories, due to its high degree of accuracy and speed to produce analytical results. An interesting alternative to X-ray fluorescence is provided by the Inductively Coupled Plasma Spectrometry technique, for those laboratories where wet chemistry facilities are already available or process control is not required at high speed, or investiment costs have to be low. This paper presents results obtained by plasma spectroscopy for the analysis of silico - aluminous refractories, showing calibration curves, precion and detection limits. Considerations and comparisons with X-ray fluorescence are also made. (author) [pt

  19. Chemical detection, identification, and analysis system

    International Nuclear Information System (INIS)

    Morel, R.S.; Gonzales, D.; Mniszewski, S.

    1990-01-01

    The chemical detection, identification, and analysis system (CDIAS) has three major goals. The first is to display safety information regarding chemical environment before personnel entry. The second is to archive personnel exposure to the environment. Third, the system assists users in identifying the stage of a chemical process in progress and suggests safety precautions associated with that process. In addition to these major goals, the system must be sufficiently compact to provide transportability, and it must be extremely simple to use in order to keep user interaction at a minimum. The system created to meet these goals includes several pieces of hardware and the integration of four software packages. The hardware consists of a low-oxygen, carbon monoxide, explosives, and hydrogen sulfide detector; an ion mobility spectrometer for airborne vapor detection; and a COMPAQ 386/20 portable computer. The software modules are a graphics kernel, an expert system shell, a data-base management system, and an interface management system. A supervisory module developed using the interface management system coordinates the interaction of the other software components. The system determines the safety of the environment using conventional data acquisition and analysis techniques. The low-oxygen, carbon monoxide, hydrogen sulfide, explosives, and vapor detectors are monitored for hazardous levels, and warnings are issued accordingly

  20. Directed transport by surface chemical potential gradients for enhancing analyte collection in nanoscale sensors.

    Science.gov (United States)

    Sitt, Amit; Hess, Henry

    2015-05-13

    Nanoscale detectors hold great promise for single molecule detection and the analysis of small volumes of dilute samples. However, the probability of an analyte reaching the nanosensor in a dilute solution is extremely low due to the sensor's small size. Here, we examine the use of a chemical potential gradient along a surface to accelerate analyte capture by nanoscale sensors. Utilizing a simple model for transport induced by surface binding energy gradients, we study the effect of the gradient on the efficiency of collecting nanoparticles and single and double stranded DNA. The results indicate that chemical potential gradients along a surface can lead to an acceleration of analyte capture by several orders of magnitude compared to direct collection from the solution. The improvement in collection is limited to a relatively narrow window of gradient slopes, and its extent strongly depends on the size of the gradient patch. Our model allows the optimization of gradient layouts and sheds light on the fundamental characteristics of chemical potential gradient induced transport.

  1. Shotgun lipidomic analysis of chemically sulfated sterols compromises analytical sensitivity

    DEFF Research Database (Denmark)

    Casanovas, Albert; Hannibal-Bach, Hans Kristian; Jensen, Ole Nørregaard

    2014-01-01

    Shotgun lipidomics affords comprehensive and quantitative analysis of lipid species in cells and tissues at high-throughput [1 5]. The methodology is based on direct infusion of lipid extracts by electrospray ionization (ESI) combined with tandem mass spectrometry (MS/MS) and/or high resolution F...... low ionization efficiency in ESI [7]. For this reason, chemical derivatization procedures including acetylation [8] or sulfation [9] are commonly implemented to facilitate ionization, detection and quantification of sterols for global lipidome analysis [1-3, 10]....

  2. Direct chemical synthesis of MnO2 nanowhiskers on MXene surfaces for supercapacitor applications

    KAUST Repository

    Baby, Rakhi Raghavan; Ahmed, Bilal; Anjum, Dalaver H.; Alshareef, Husam N.

    2016-01-01

    Transition metal carbides (MXenes) are an emerging class of two dimensional (2D) materials with promising electrochemical energy storage performance. Herein, for the first time, by direct chemical synthesis, nanocrystalline ε-MnO2 whiskers were

  3. The development of chemical speciation analysis

    International Nuclear Information System (INIS)

    Martin, R.; Santana, J.L.; Lima, L.; De La Rosa, D.; Melchor, K.

    2003-01-01

    The knowledge of many metals species on the environmental, its bioaccumulation, quantification and its effect in human body has been studied by a wide researchers groups in the last two decades. The development of speciation analysis has an vertiginous advance close to the developing of novel analytical techniques. Separation and quantification at low level is a problem that's has been afford by a coupling of high resolution chromatographic techniques like HPLC and HRGC with a specific method of detection (ICP-MS or CV-AAS). This methodological approach make possible the success in chemical speciation nowadays

  4. Laser chemical analysis: the recent developments

    International Nuclear Information System (INIS)

    Mauchien, P.

    1997-01-01

    This paper gives a general overview and describes the principles of the main laser-based techniques for physical and chemical analysis, and of their recent developments. Analytical techniques using laser radiations were actually developed at the end of the 1970's. The recent evolutions concern the 3 principal techniques of laser spectroscopy currently used: Raman, fluorescence (atomic and molecular) and ablation (ICP laser ablation-plasma coupling, optical emission spectroscopy on laser-induced plasma). The description of these different techniques is illustrated with some examples of applications. (J.S.)

  5. Activation and chemical analysis of drinking waters

    International Nuclear Information System (INIS)

    Sharma, H.K.; Mittal, V.K.; Sahota, H.S.

    1989-01-01

    Ground water samples from Patiala city have been analysed for 22 trace elements using neutron activation analysis and for seven chemical parameters using standard techniques. It was found that alkali and alkaline earth metals have high concentrations in all samples whereas the concentrations of toxic metals are low in the majority of samples. However, chromium and cadmium concentrations are higher in ground water taken from the industrial belt of the city. This indicates that the overall level of pollution is low, but that some measures are still needed to inhibit various industries from polluting the ground water. (author)

  6. Development of chemical equilibrium analysis code 'CHEEQ'

    International Nuclear Information System (INIS)

    Nagai, Shuichiro

    2006-08-01

    'CHEEQ' code which calculates the partial pressure and the mass of the system consisting of ideal gas and pure condensed phase compounds, was developed. Characteristics of 'CHEEQ' code are as follows. All the chemical equilibrium equations were described by the formation reactions from the mono-atomic gases in order to simplify the code structure and input preparation. Chemical equilibrium conditions, Σν i μ i =0 for the gaseous compounds and precipitated condensed phase compounds and Σν i μ i > 0 for the non-precipitated condensed phase compounds, were applied. Where, ν i and μ i are stoichiometric coefficient and chemical potential of component i. Virtual solid model was introduced to perform the calculation of constant partial pressure condition. 'CHEEQ' was consisted of following 3 parts, (1) analysis code, zc132. f. (2) thermodynamic data base, zmdb01 and (3) input data file, zindb. 'CHEEQ' code can calculate the system which consisted of elements (max.20), condensed phase compounds (max.100) and gaseous compounds. (max.200). Thermodynamic data base, zmdb01 contains about 1000 elements and compounds, and 200 of them were Actinide elements and their compounds. This report describes the basic equations, the outline of the solution procedure and instructions to prepare the input data and to evaluate the calculation results. (author)

  7. VALIDATION GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    Science.gov (United States)

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following guidelines for laboratories engaged in the forensic analysis of chemical evidence associated with terrorism. This document provides a baseline framework and guidance for...

  8. direct method of analysis of an isotropic rectangular plate direct

    African Journals Online (AJOL)

    eobe

    This work evaluates the static analysis of an isotropic rectangular plate with various the static analysis ... method according to Ritz is used to obtain the total potential energy of the plate by employing the used to ..... for rectangular plates analysis, as the behavior of the ... results obtained by previous research work that used.

  9. Spatial control of direct chemical vapor deposition of graphene on silicon dioxide by directional copper dewetting

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    In this paper we present a method for the spatial control of direct graphene synthesis onto silicon dioxide by controlled dewetting. The dewetting process is controlled through a combination of using a grooved substrate and conducting copper deposition at an angle. The substrate is then treated

  10. Direct reading spectrochemical analysis of sodium uranate

    International Nuclear Information System (INIS)

    Roca, M.; Capdevila, C.

    1966-01-01

    We describe the application of the quantometer to the analysis of sodium uranate. To determine boron, cadmium, phosphorus and molybdenum contents, the samples are mixed with graphite powder (1:30) and excited in a 10 amperes direct current arc with 4x4,,5 mm cup graphite rods, using silver as internal standard. A not se deep cup and a dilution factor of 90 are more suitable for calcium, copper, iron, silicon and vanadium determination; cobalt and chromium are the internal standards. (Author) 6 refs

  11. Challenges in effect-directed analysis with a focus on biological samples

    NARCIS (Netherlands)

    Simon, E.; Lamoree, M.H.; Hamers, T.; de Boer, J.

    2015-01-01

    Effect-directed analysis (EDA), the combined use of bioassay-guided fractionation and analytical chemical techniques, enables detection of chemicals by their effects, facilitates identification of non-target compounds and transformation products with a certain toxic mode of action and assists in

  12. Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications.

    Science.gov (United States)

    Massaro, M; Amorati, R; Cavallaro, G; Guernelli, S; Lazzara, G; Milioto, S; Noto, R; Poma, P; Riela, S

    2016-04-01

    Covalently functionalized halloysite nanotubes (HNTs) were successfully employed as dual-responsive nanocarriers for curcumin (Cur). Particularly, we synthesized HNT-Cur prodrug with a controlled curcumin release on dependence of both intracellular glutathione (GSH) and pH conditions. In order to obtain HNT-Cur produgs, halloysite was firstly functionalized with cysteamine through disulphide linkage. Afterwards, curcumin molecules were chemically conjugated to the amino end groups of halloysite via Schiff's base formation. The successful functionalization of halloysite was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and scanning electron microscopy. Experimental data confirmed the presence of curcumin on HNT external surface. Moreover, we investigated the kinetics of curcumin release by UV-vis spectroscopy, which highlighted that HNT-Cur prodrug possesses dual stimuli-responsive ability upon exposure to GSH-rich or acidic environment. In vitro antiproliferative and antioxidant properties of HNT-Cur prodrug were studied with the aim to explore their potential applications in pharmaceutics. This work puts forward an efficient strategy to prepare halloysite based nanocarriers with controlled drug delivery capacity through direct chemical grafting with stimuli-responsive linkage. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Google matrix analysis of directed networks

    Science.gov (United States)

    Ermann, Leonardo; Frahm, Klaus M.; Shepelyansky, Dima L.

    2015-10-01

    In the past decade modern societies have developed enormous communication and social networks. Their classification and information retrieval processing has become a formidable task for the society. Because of the rapid growth of the World Wide Web, and social and communication networks, new mathematical methods have been invented to characterize the properties of these networks in a more detailed and precise way. Various search engines extensively use such methods. It is highly important to develop new tools to classify and rank a massive amount of network information in a way that is adapted to internal network structures and characteristics. This review describes the Google matrix analysis of directed complex networks demonstrating its efficiency using various examples including the World Wide Web, Wikipedia, software architectures, world trade, social and citation networks, brain neural networks, DNA sequences, and Ulam networks. The analytical and numerical matrix methods used in this analysis originate from the fields of Markov chains, quantum chaos, and random matrix theory.

  14. Computational Chemical Synthesis Analysis and Pathway Design

    Directory of Open Access Journals (Sweden)

    Fan Feng

    2018-06-01

    Full Text Available With the idea of retrosynthetic analysis, which was raised in the 1960s, chemical synthesis analysis and pathway design have been transformed from a complex problem to a regular process of structural simplification. This review aims to summarize the developments of computer-assisted synthetic analysis and design in recent years, and how machine-learning algorithms contributed to them. LHASA system started the pioneering work of designing semi-empirical reaction modes in computers, with its following rule-based and network-searching work not only expanding the databases, but also building new approaches to indicating reaction rules. Programs like ARChem Route Designer replaced hand-coded reaction modes with automatically-extracted rules, and programs like Chematica changed traditional designing into network searching. Afterward, with the help of machine learning, two-step models which combine reaction rules and statistical methods became the main stream. Recently, fully data-driven learning methods using deep neural networks which even do not require any prior knowledge, were applied into this field. Up to now, however, these methods still cannot replace experienced human organic chemists due to their relatively low accuracies. Future new algorithms with the aid of powerful computational hardware will make this topic promising and with good prospects.

  15. Identifying the nature of surface chemical modification for directed self-assembly of block copolymers

    Directory of Open Access Journals (Sweden)

    Laura Evangelio

    2017-09-01

    Full Text Available In recent years, block copolymer lithography has emerged as a viable alternative technology for advanced lithography. In chemical-epitaxy-directed self-assembly, the interfacial energy between the substrate and each block copolymer domain plays a key role on the final ordering. Here, we focus on the experimental characterization of the chemical interactions that occur at the interface built between different chemical guiding patterns and the domains of the block copolymers. We have chosen hard X-ray high kinetic energy photoelectron spectroscopy as an exploration technique because it provides information on the electronic structure of buried interfaces. The outcome of the characterization sheds light onto key aspects of directed self-assembly: grafted brush layer, chemical pattern creation and brush/block co-polymer interface.

  16. Comparative Analysis on Chemical Composition of Bentonite Clays ...

    African Journals Online (AJOL)

    2017-09-12

    Sep 12, 2017 ... Comparative Analysis on Chemical Composition of Bentonite Clays. Obtained from Ashaka and ... versatile material for geotechnical engineering and as well as their demand for ..... A PhD thesis submitted to the Chemical ...

  17. Analysis of forward and inverse problems in chemical dynamics and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rabitz, H. [Princeton Univ., NJ (United States)

    1993-12-01

    The overall scope of this research concerns the development and application of forward and inverse analysis tools for problems in chemical dynamics and chemical kinetics. The chemical dynamics work is specifically associated with relating features in potential surfaces and resultant dynamical behavior. The analogous inverse research aims to provide stable algorithms for extracting potential surfaces from laboratory data. In the case of chemical kinetics, the focus is on the development of systematic means to reduce the complexity of chemical kinetic models. Recent progress in these directions is summarized below.

  18. Novel chemical analysis for thin films

    International Nuclear Information System (INIS)

    Usui, Toshio; Kamei, Masayuki; Aoki, Yuji; Morishita, Tadataka; Tanaka, Shoji

    1991-01-01

    Scanning electron microscopy and total-reflection-angle X-ray spectroscopy (SEM-TRAXS) was applied for fluorescence X-ray analysis of 50A- and 125A-thick Au thin films on Si(100). The intensity of the AuM line (2.15 keV) emitted from the Au thin films varied as a function of the take-off angle (θ t ) with respect to the film surface; the intensity of AuM line from the 125A-thick Au thin film was 1.5 times as large as that of SiK α line (1.74 keV) emitted from the Si substrate when θ t = 0deg-3deg, in the vicinity of a critical angle for total external reflection of the AuM line at Si (0.81deg). In addition, the intensity of the AuM line emitted from the 50A-thick Au thin film was also sufficiently strong for chemical analysis. (author)

  19. Analysis of directly driven ICF targets

    International Nuclear Information System (INIS)

    Velarde, G.; Aragones, J.M.; Gago, J.A.

    1986-01-01

    The current capabilities at DENIM for the analysis of directly driven targets are presented. These include theoretical, computational and applied physical studies and developments of detailed simulation models for the most relevant processes in ICF. The simulation of directly driven ICF targets is carried out with the one-dimensional NORCLA code developed at DENIM. This code contains two main segments: NORMA and CLARA, able to work fully coupled and in an iterative manner. NORMA solves the hydrodynamic equations in a lagrangian mesh. It has modular programs couple to it to treat the laser or particle beam interaction with matter. Equations of state, opacities and conductivities are taken from a DENIM atomic data library, generated externally with other codes that will also be explained in this work. CLARA solves the transport equation for neutrons, as well as for charged particles, and suprathermal electrons using discrete ordinates and finite element methods in the computational procedure. Parametric calculations of multilayered single-shell targets driven by heavy ion beams are also analyzed. Finally, conclusions are focused on the ongoing developments in the areas of interest such as: radiation transport, atomic physics, particle in cell method, charged particle transport, two-dimensional calculations and instabilities. (author)

  20. Rate-distortion analysis of directional wavelets.

    Science.gov (United States)

    Maleki, Arian; Rajaei, Boshra; Pourreza, Hamid Reza

    2012-02-01

    The inefficiency of separable wavelets in representing smooth edges has led to a great interest in the study of new 2-D transformations. The most popular criterion for analyzing these transformations is the approximation power. Transformations with near-optimal approximation power are useful in many applications such as denoising and enhancement. However, they are not necessarily good for compression. Therefore, most of the nearly optimal transformations such as curvelets and contourlets have not found any application in image compression yet. One of the most promising schemes for image compression is the elegant idea of directional wavelets (DIWs). While these algorithms outperform the state-of-the-art image coders in practice, our theoretical understanding of them is very limited. In this paper, we adopt the notion of rate-distortion and calculate the performance of the DIW on a class of edge-like images. Our theoretical analysis shows that if the edges are not "sharp," the DIW will compress them more efficiently than the separable wavelets. It also demonstrates the inefficiency of the quadtree partitioning that is often used with the DIW. To solve this issue, we propose a new partitioning scheme called megaquad partitioning. Our simulation results on real-world images confirm the benefits of the proposed partitioning algorithm, promised by our theoretical analysis. © 2011 IEEE

  1. Effect-directed analysis: Current status and future challenges

    Science.gov (United States)

    Hong, Seongjin; Giesy, John P.; Lee, Jung-Suk; Lee, Jong-Hyeon; Khim, Jong Seong

    2016-09-01

    Effect-directed analysis (EDA) has become useful for identification of toxicant(s) that occur in mixtures in the environment, especially those that are causative agents of specific adverse effects. Here, we summarize and review EDA methodology including preparation of samples, biological analyses, fractionations, and instrumental analyses, highlighting key scientific advancements. A total of 63 documents since 1999 (Scopus search) including 46 research articles, 13 review papers, and 4 project descriptions, have been collected and reviewed in this study. At the early stage (1999-2010), most studies that applied EDA focused on organic extracts of freshwater and coastal contaminated sediments and wastewater. Toxic effects were often measured using cell-based bioassays ( in vitro) and the causative chemicals were identified by use of low resolution gas chromatography with mass selective detector (GCMSD). More recently (2010-present), EDA has been extended to various matrices such as biota, soil, crude oil, and suspended solids and techniques have been improved to include determination of bioavailability in vivo. In particular, methods for non-target screenings of organic chemicals in environmental samples using cutting-edge instrumentation such as time of flight-mass spectrometry (ToF-MS), Fourier transform-ion cyclotron resonance (FT-ICR), and Orbitrap mass spectrometer have been developed. This overview provides descriptions of recent improvements of EDA and suggests future research directions based on current understandings and limitations.

  2. Thermodynamic analysis of chemical heat pumps

    International Nuclear Information System (INIS)

    Obermeier, Jonas; Müller, Karsten; Arlt, Wolfgang

    2015-01-01

    Thermal energy storages and heat pump units represent an important part of high efficient renewable energy systems. By using thermally driven, reversible chemical reactions a combination of thermal energy storage and heat pump can be realized. The influences of thermophysical properties of the involved components on the efficiency of a heat pump cycle is analysed and the relevance of the thermodynamic driving force is worked out. In general, the behaviour of energetic and exergetic efficiency is contrary. In a real cycle, higher enthalpies of reaction decrease the energetic efficiency but increase the exergetic efficiency. Higher enthalpies of reaction allow for lower offsets from equilibrium state for a default thermodynamic driving force of the reaction. - Highlights: • A comprehensive efficiency analysis of gas-solid heat pumps is proposed. • Link between thermodynamic driving force and equilibrium drop is shown. • Calculation of the equilibrium drop based on thermochemical properties. • Reaction equilibria of the decomposition reaction of salt hydrates. • Contrary behavior of energetic and exergetic efficiency

  3. Status and direction of waste minimization in the chemical and petrochemical industries

    Energy Technology Data Exchange (ETDEWEB)

    Englande Junior, A.J. [Tulane Univ., New Orleans, LA (United States). School of Public Health and Tropical Medicine

    1993-12-31

    This paper presents an evaluation of the status and direction of toxic/hazardous waste reduction in chemical and petrochemical industries from an international perspective. In almost all cases studied savings have resulted. The importance of pollution prevention by `clean technologies` instead of remediation is stressed. 6 refs., 4 tabs.

  4. Status and direction of waste minimization in the chemical and petrochemical industries

    Energy Technology Data Exchange (ETDEWEB)

    Englande, Junior, A J [Tulane Univ., New Orleans, LA (United States). School of Public Health and Tropical Medicine

    1994-12-31

    This paper presents an evaluation of the status and direction of toxic/hazardous waste reduction in chemical and petrochemical industries from an international perspective. In almost all cases studied savings have resulted. The importance of pollution prevention by `clean technologies` instead of remediation is stressed. 6 refs., 4 tabs.

  5. Fast analysis of narcotic drugs by optical chemical imaging

    International Nuclear Information System (INIS)

    Fisher, Michal; Bulatov, Vallery; Schechter, Israel

    2003-01-01

    A new technique is proposed for fast detection, identification and imaging of narcotic drugs in their solid phase. This technique, which requires only a tiny sample of a few microns, is based on microscopic chemical imaging. Minor sample preparation is required, and results are obtained within seconds. As far as we know, this is the most sensitive detection system available today for solid drugs. The technique can be applied for fast analysis of minute drug residues, and therefore is of considerable importance for forensic applications. It is shown that identification of drug traces in realistic matrixes is possible. Two main methods were applied in this study for detection of drugs and drug derivatives. The first method was based on direct detection and chemical imaging of the auto-fluorescence of the analyzed drugs. This method is applicable when the analyzed drug emits fluorescence under the experiment conditions, such as lysergic acid diethylamide (known as LSD). The second method was used for obtaining chemical imaging of drugs that do not fluoresce under the experiment conditions. In these cases fluorescent labeling dyes were applied to the examined samples (including the drug and the matrix). Both methods are simple and rapid, and require minor or no sample preparation at all. Detection limits are very low in the picogram range

  6. Kinetics of directed self-assembly of block copolymers on chemically patterned substrates

    International Nuclear Information System (INIS)

    Müller, Marcus; Li, Weihua; Rey, Juan Carlos Orozco; Welling, Ulrich

    2015-01-01

    Chemically patterned surfaces have been successfully employed to direct the kinetics of self-assembly of block copolymers into dense, periodic morphologies (”chemoepitaxy”). Significant efforts have been directed towards understanding the kinetics of structure formation and, particularly, the formation and annihilation of defects. In the present manuscript we use computer simulations of a soft, coarse-grained polymer model to study the kinetics of structure formation of lamellar-forming block copolymer thin films on a chemical pattern of lines and spaces. The case where the copolymer material replicates the surface pattern and the more subtle scenario of sparse guiding patterns are considered. Our simulation results highlight (1) the importance of the early stages of pattern-directed self-assembly that template the subsequent morphology and (2) the dependence of the free-energy landscape on the incompatibility between the two blocks of the copolymer. (paper)

  7. Direct solution of the Chemical Master Equation using quantized tensor trains.

    Directory of Open Access Journals (Sweden)

    Vladimir Kazeev

    2014-03-01

    Full Text Available The Chemical Master Equation (CME is a cornerstone of stochastic analysis and simulation of models of biochemical reaction networks. Yet direct solutions of the CME have remained elusive. Although several approaches overcome the infinite dimensional nature of the CME through projections or other means, a common feature of proposed approaches is their susceptibility to the curse of dimensionality, i.e. the exponential growth in memory and computational requirements in the number of problem dimensions. We present a novel approach that has the potential to "lift" this curse of dimensionality. The approach is based on the use of the recently proposed Quantized Tensor Train (QTT formatted numerical linear algebra for the low parametric, numerical representation of tensors. The QTT decomposition admits both, algorithms for basic tensor arithmetics with complexity scaling linearly in the dimension (number of species and sub-linearly in the mode size (maximum copy number, and a numerical tensor rounding procedure which is stable and quasi-optimal. We show how the CME can be represented in QTT format, then use the exponentially-converging hp-discontinuous Galerkin discretization in time to reduce the CME evolution problem to a set of QTT-structured linear equations to be solved at each time step using an algorithm based on Density Matrix Renormalization Group (DMRG methods from quantum chemistry. Our method automatically adapts the "basis" of the solution at every time step guaranteeing that it is large enough to capture the dynamics of interest but no larger than necessary, as this would increase the computational complexity. Our approach is demonstrated by applying it to three different examples from systems biology: independent birth-death process, an example of enzymatic futile cycle, and a stochastic switch model. The numerical results on these examples demonstrate that the proposed QTT method achieves dramatic speedups and several orders of

  8. availability analysis of chemicals for water treatment

    African Journals Online (AJOL)

    NIJOTECH

    In most countries, chemicals are generally recognized as being vital in the production of potable water and will ... industries and water utility ventures are being started in Nigeria ... are being dumped into rivers thereby polluting them the more.

  9. Direct Quantitative Analysis of Arsenic in Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Sri Hartuti

    2012-01-01

    Full Text Available A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier and the optimization of the parameters in the furnace program (temperature, rate of temperature increase, hold time, and argon gas flow gave good results for the total arsenic determination. The optimal furnace program was determined by analyzing different concentrations of a reference material (NIST1633b, which showed the best linearity for calibration. The optimized parameters for the furnace programs for the ashing and atomization steps were as follows: temperatures of 500–1200 and 2150°C, heating rates of 100 and 500°C s−1, hold times of 90 and 7 s, and medium then maximum and medium argon gas flows, respectively. The calibration plots were linear with a correlation coefficient of 0.9699. This method was validated using arsenic-containing raw coal samples in accordance with the requirements of the mass balance calculation; the distribution rate of As in the fly ashes ranged from 101 to 119%.

  10. Proposed minimum reporting standards for chemical analysis Chemical Analysis Working Group (CAWG) Metabolomics Standards Initiative (MSI)

    Science.gov (United States)

    Amberg, Alexander; Barrett, Dave; Beale, Michael H.; Beger, Richard; Daykin, Clare A.; Fan, Teresa W.-M.; Fiehn, Oliver; Goodacre, Royston; Griffin, Julian L.; Hankemeier, Thomas; Hardy, Nigel; Harnly, James; Higashi, Richard; Kopka, Joachim; Lane, Andrew N.; Lindon, John C.; Marriott, Philip; Nicholls, Andrew W.; Reily, Michael D.; Thaden, John J.; Viant, Mark R.

    2013-01-01

    There is a general consensus that supports the need for standardized reporting of metadata or information describing large-scale metabolomics and other functional genomics data sets. Reporting of standard metadata provides a biological and empirical context for the data, facilitates experimental replication, and enables the re-interrogation and comparison of data by others. Accordingly, the Metabolomics Standards Initiative is building a general consensus concerning the minimum reporting standards for metabolomics experiments of which the Chemical Analysis Working Group (CAWG) is a member of this community effort. This article proposes the minimum reporting standards related to the chemical analysis aspects of metabolomics experiments including: sample preparation, experimental analysis, quality control, metabolite identification, and data pre-processing. These minimum standards currently focus mostly upon mass spectrometry and nuclear magnetic resonance spectroscopy due to the popularity of these techniques in metabolomics. However, additional input concerning other techniques is welcomed and can be provided via the CAWG on-line discussion forum at http://msi-workgroups.sourceforge.net/ or http://Msi-workgroups-feedback@lists.sourceforge.net. Further, community input related to this document can also be provided via this electronic forum. PMID:24039616

  11. Physico-Chemical Analysis and Sensory Evaluation of Bread

    African Journals Online (AJOL)

    Shuaibu et al.

    Physico-Chemical Analysis and Sensory Evaluation of Bread Produced Using ... analysis of the bread samples revealed that the moisture content ..... 72. Jarup, L. ,2003. Hazards of heavy metal contamination. Br Med. Bull; 68, pp.167-82.

  12. Chemical analysis and base-promoted hydrolysis of locally ...

    African Journals Online (AJOL)

    Abstract. The study was on the chemical analysis and base- promoted hydrolysis of extracted shea nut fat. The local method of extraction of the shea nut oil was employed in comparison with literature report. A simple cold-process alkali hydrolysis of the shea nut oil was used in producing the soap. The chemical analysis of ...

  13. Safety- and Risk Analysis Activities in Chemical Industry in Europe

    International Nuclear Information System (INIS)

    Kozine, Igor; Duijm, Nijs Jan; Lauridsen Kurt

    2001-01-01

    The current paper gives an overview of the legislation and the methods used in safety and risk management in the chemical industry within Europe and in particular within the European Union. The paper is based on a report that has been written for the SOS-1 project under the Nordic nuclear safety research (NKS). Safety- and risk-related matters in the process industry, in particular, in chemical, within the EU are subject to consideration at three levels: (1) EU legislation, (2) European/intemational standardisation, and (3) socio-economic analysis. EC Directives define the 'essential requirements', e.g., protection of health and safety, that must be fulfilled when goods are placed on the market or some industry is put into operation. The European standards bodies (CEN, CENELEC and ETSI) have the task of establishing the corresponding technical specifications, meeting the essential requirements of the Directives, compliance with which will provide a presumption of conformity with the essential requirements. Such specifications are referred to as 'harmonised standards'. Compliance with harmonised standards remains voluntary, and manufacturers are free to choose any other technical solution that provides compliance with the essential requirements. This view is stated in the 'New Approach' to technical harmonisation and standardisation (details can be found on the web page: http://europe.eu.int/comm/enterprise/newapproach/standardization/index .html). Standardisation as well as the regulation of technical risks is increasingly being undertaken at European or international level. The European legislator limits its role to the affirmation of overall objectives, and leaves it to the economic players to draw up the technical procedures and standards to specify in detail the ways and means of attaining them. Many countries have introduced requirements that new legislation and/or administrative regulations be subject to socio-economic analysis. In this respect there is a

  14. Direct conversion of radioactive and chemical waste containing metals, ceramics, amorphous solids, and organics to glass

    International Nuclear Information System (INIS)

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1994-01-01

    The Glass Material Oxidation and Dissolution System (CMODS) is a new process for direct conversion of radioactive, mixed, and chemical wastes to glass. The wastes can be in the chemical forms of metals, ceramics, amorphous solids, and organics. GMODS destroys organics and it incorporates heavy metals and radionuclides into a glass. Processable wastes may include miscellaneous spent fuels (SF), SF hulls and hardware, plutonium wastes in different forms, high-efficiency particulate air (HEPA) filters, ion-exchange resins, failed equipment, and laboratory wastes. Thermodynamic calculations indicate theoretical feasibility. Small-scale laboratory experiments (< 100 g per test) have demonstrated chemical laboratory feasibility for several metals. Additional work is needed to demonstrate engineering feasibility

  15. Thermally emissive sensing materials for chemical spectroscopy analysis

    Science.gov (United States)

    Poole, Zsolt; Ohodnicki, Paul R.

    2018-05-08

    A sensor using thermally emissive materials for chemical spectroscopy analysis includes an emissive material, wherein the emissive material includes the thermally emissive materials which emit electromagnetic radiation, wherein the electromagnetic radiation is modified due to chemical composition in an environment; and a detector adapted to detect the electromagnetic radiation, wherein the electromagnetic radiation is indicative of the chemical interaction changes and hence chemical composition and/or chemical composition changes of the environment. The emissive material can be utilized with an optical fiber sensor, with the optical fiber sensor operating without the emissive material probed with a light source external to the material.

  16. Direct dry transfer of chemical vapor deposition graphene to polymeric substrates

    OpenAIRE

    Fechine, Guilhermino J. M.; Martin-Fernandez, Inigo; Yiapanis, George; de Oliveira, Ricardo V. Bof; Hu, Xiao; Yarovsky, Irene; Neto, Antonio H. Castro; Ozyilmaz, Barbaros

    2014-01-01

    We demonstrate the direct dry transfer of large area Chemical Vapor Deposition graphene to several polymers (low density polyethylene, high density polyethylene, polystyrene, polylactide acid and poly(vinylidenefluoride-co-trifluoroethylene) by means of only moderate heat and pressure, and the later mechanical peeling of the original graphene substrate. Simulations of the graphene-polymer interactions, rheological tests and graphene transfer at various experimental conditions show that contro...

  17. Chemical and thermal analysis for characterisation of building materials

    International Nuclear Information System (INIS)

    Kumar, S.C.; Sudersanan, M.; Ravindran, P.V.; Kalekar, B.B.; Mathur, P.K.

    2000-01-01

    Cement and other construction materials are extensively used for the construction of shielding materials for nuclear and high energy radiations. The design and optimum utilisation of such materials need an accurate analysis of their chemical composition. The moisture content and presence of bound water and other volatile materials are also important. The use of thermal analysis supplements the data obtained by chemical analysis and enables a distinction of moisture and chemically bound water. It also enables an identification of the process leading to the loss on ignition. The work carried out on the analysis of sand, cement and other aggregate materials used for the preparation of concrete is described in the paper. (author)

  18. Chemical Diversity, Origin, and Analysis of Phycotoxins

    DEFF Research Database (Denmark)

    Rasmussen, Silas Anselm; Andersen, Aaron John Christian; Andersen, Nikolaj Gedsted

    2016-01-01

    , yessotoxins, azaspiracids, brevetoxins, and pinnatoxins. Other toxins, such as ciguatoxins and maitotoxins, accumulate in fish, where, as is the case for the latter compounds, they can be metabolized to even more toxic metabolites. On the other hand, much less is known about the chemical nature of compounds...

  19. Direct reading spectrochemical analysis of nuclear graphite

    International Nuclear Information System (INIS)

    Roca Adell, M.; Becerro Ruiz, E.; Alvarez Gonzalez, F.

    1964-01-01

    A description is given about the application of a direct-reading spectrometer the Quantometer, to the determination of boron. calcium, iron, titanium and vanadium in nuclear grade graphite. for boron the powdered sample is mixed with 1% cupric fluoride and excited in a 10-amperes direct current arc and graphite electrodes with a crater 7 mm wide and 10 mm deep. For the other elements a smaller crater has been used and dilution with a number of matrices has been investigated; the best results are achieved by employing 25% cupric fluoride. The sensitivity limit for boron is 0,15 ppm. (Author) 21 refs

  20. Stability analysis of directly driven Nif capsules

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, V.N.; Skupsky, S.; McKenty, P.W.; Delettrez, J.A.; Town, R.P.J. [Rochester Univ., NY (United States). Lab. for Laser Energetics; Cherfils-Clerouin, C. [CEA/DAM-Ile de France, DIF, 91 - Bruyeres Le Chatel (France)

    2000-07-01

    An analytical model is presented to study perturbation evolution at the ablation and inner surfaces of the imploding shell. The model describes the ablative Rayleigh-Taylor and Bell-Plesset instabilities. The initial conditions for the model are determined by using existing theories of laser imprint, ablative Richtmyer-Meshkov instability, 'feed-out' and by performing a series of 2-D ORCHID simulations. The model and simulations show that the direct-drive cryogenic {alpha} = 3 NIF capsules remain intact during the implosion if laser nonuniformities are smoothed by 2-D SSD used in the current direct-drive target designs. (authors)

  1. Geodetic analysis of disputed accurate qibla direction

    Science.gov (United States)

    Saksono, Tono; Fulazzaky, Mohamad Ali; Sari, Zamah

    2018-04-01

    Muslims perform the prayers facing towards the correct qibla direction would be the only one of the practical issues in linking theoretical studies with practice. The concept of facing towards the Kaaba in Mecca during the prayers has long been the source of controversy among the muslim communities to not only in poor and developing countries but also in developed countries. The aims of this study were to analyse the geodetic azimuths of qibla calculated using three different models of the Earth. The use of ellipsoidal model of the Earth could be the best method for determining the accurate direction of Kaaba from anywhere on the Earth's surface. A muslim cannot direct himself towards the qibla correctly if he cannot see the Kaaba due to setting out process and certain motions during the prayer this can significantly shift the qibla direction from the actual position of the Kaaba. The requirement of muslim prayed facing towards the Kaaba is more as spiritual prerequisite rather than physical evidence.

  2. Analysis of chemical constituents in Cistanche species.

    Science.gov (United States)

    Jiang, Yong; Tu, Peng-Fei

    2009-03-13

    Species of the genus of Cistanche (Rou Cong Rong in Chinese) are perennial parasite herbs, and are mainly distributed in arid lands and warm deserts. As a superior tonic for the treatment of kidney deficiency, impotence, female infertility, morbid leucorrhea, profuse metrorrhagia and senile constipation, Cistanche herbs earned the honor of "Ginseng of the desert". Recently, there has been increasing scientific attention on Herba Cistanche for its remarkable bioactivities including antioxidation, neuroprotection, and anti-aging. The chemical constituents of Cistanche plants mainly include volatile oils and non-volatile phenylethanoid glycosides (PhGs), iridoids, lignans, alditols, oligosaccharides and polysaccharides. Pharmacological studies show that PhGs are the main active components for curing kidney deficiency, antioxidation and neuroprotection; galactitol and oligosaccharides are the representatives for the treatment of senile constipation, while polysaccharides are responsible for improving body immunity. In this paper, the advances on the chemical constituents of Cistanche plants and their corresponding analyses are reviewed.

  3. Hybrid chemical and nondestructive-analysis technique

    International Nuclear Information System (INIS)

    Hsue, S.T.; Marsh, S.F.; Marks, T.

    1982-01-01

    A hybrid chemical/NDA technique has been applied at the Los Alamos National Laboratory to the assay of plutonium in ion-exchange effluents. Typical effluent solutions contain low concentrations of plutonium and high concentrations of americium. A simple trioctylphosphine oxide (TOPO) separation can remove 99.9% of the americium. The organic phase that contains the separated plutonium can be accurately assayed by monitoring the uranium L x-ray intensities

  4. Avogadro: an advanced semantic chemical editor, visualization, and analysis platform.

    Science.gov (United States)

    Hanwell, Marcus D; Curtis, Donald E; Lonie, David C; Vandermeersch, Tim; Zurek, Eva; Hutchison, Geoffrey R

    2012-08-13

    The Avogadro project has developed an advanced molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible, high quality rendering, and a powerful plugin architecture. Typical uses include building molecular structures, formatting input files, and analyzing output of a wide variety of computational chemistry packages. By using the CML file format as its native document type, Avogadro seeks to enhance the semantic accessibility of chemical data types. The work presented here details the Avogadro library, which is a framework providing a code library and application programming interface (API) with three-dimensional visualization capabilities; and has direct applications to research and education in the fields of chemistry, physics, materials science, and biology. The Avogadro application provides a rich graphical interface using dynamically loaded plugins through the library itself. The application and library can each be extended by implementing a plugin module in C++ or Python to explore different visualization techniques, build/manipulate molecular structures, and interact with other programs. We describe some example extensions, one which uses a genetic algorithm to find stable crystal structures, and one which interfaces with the PackMol program to create packed, solvated structures for molecular dynamics simulations. The 1.0 release series of Avogadro is the main focus of the results discussed here. Avogadro offers a semantic chemical builder and platform for visualization and analysis. For users, it offers an easy-to-use builder, integrated support for downloading from common databases such as PubChem and the Protein Data Bank, extracting chemical data from a wide variety of formats, including computational chemistry output, and native, semantic support for the CML file format. For developers, it can be easily extended via a powerful

  5. Controlling the accuracy of chemical analysis

    International Nuclear Information System (INIS)

    Suschny, O.; Danesi, P.R.

    1991-01-01

    The involvement of the IAEA in quantitative analysis began in the early 1960's with radiochemical work connected with the environment. It than expanded to cover analysis (mostly by nuclear techniques) of samples for projects associated with human health, agriculture, hydrology and international safeguards. This article highlights the IAEA activities in the field of quality control in quantitative analysis

  6. Application of direct thermometric analysis in iodometry.

    Science.gov (United States)

    Marik-Korda, P; Erdey, L

    1970-12-01

    Elementary chlorine was determined by a thermometric method using potassium iodide as reagent. The temperature rise corresponding to the heat of reaction was proportional to the chlorine content. Iodine formed in the reaction was also determined with sodium thiosulphate. The heat of the chlorine-iodide reaction is about five times that of the iodine-thiosulphate reaction. Direct determination with potassium iodide is simpler and more rapid than the indirect one.

  7. Analysis of Lithuanian Direct Investment into European Union Countries

    Directory of Open Access Journals (Sweden)

    Evelina Zigmantavičiūtė

    2015-05-01

    Full Text Available In this paper the valuation of macroeconomic factors influencing the Lithuanian direct investment into European Union was conducted. The problem of this paper is the different chosen macroeconomic factors influencing foreign direct investment. The object of this paper is Lithuanian direct investment. The methods of this paper include: comparative literature analysis, correlation regression analysis, paired regression analysis. After conducting a research of dependency of Lithuanian direct investment to EU countries from price changes, government sector income, gross domestic product, inflation, jobless rate results, it is found that gross domestic product and government sector income have the most influence on the changes of Lithuanian direct investment.

  8. Use of direct washing of chemical dispense nozzle for defect control

    Science.gov (United States)

    Linnane, Michael; Mack, George; Longstaff, Christopher; Winter, Thomas

    2006-03-01

    Demands for continued defect reduction in 300mm IC manufacturing are driving process engineers to examine all aspects of the chemical apply process for improvement. Historically, the defect contribution from photoresist apply nozzles has been minimized through a carefully controlled process of "dummy dispenses" to keep the photoresist in the tip "fresh" and remove any solidified material, a preventive maintenance regime involving periodic cleaning or replacing of the nozzles, and reliance on a pool of solvent within the nozzle storage block to keep the photoresist from solidifying at the nozzle tip. The industry standard has worked well for the most part but has limitations in terms of cost effectiveness and absolute defect elimination. In this study, we investigate the direct washing of the chemical apply nozzle to reduce defects seen on the coated wafer. Data is presented on how the direct washing of the chemical dispense nozzle can be used to reduce coating related defects, reduce material costs from the reduction of "dummy dispense", and can reduce equipment downtime related to nozzle cleaning or replacement.

  9. Direct Reprogramming of Fibroblasts via a Chemically Induced XEN-like State.

    Science.gov (United States)

    Li, Xiang; Liu, Defang; Ma, Yantao; Du, Xiaomin; Jing, Junzhan; Wang, Lipeng; Xie, Bingqing; Sun, Da; Sun, Shaoqiang; Jin, Xueqin; Zhang, Xu; Zhao, Ting; Guan, Jingyang; Yi, Zexuan; Lai, Weifeng; Zheng, Ping; Huang, Zhuo; Chang, Yanzhong; Chai, Zhen; Xu, Jun; Deng, Hongkui

    2017-08-03

    Direct lineage reprogramming, including with small molecules, has emerged as a promising approach for generating desired cell types. We recently found that during chemical induction of induced pluripotent stem cells (iPSCs) from mouse fibroblasts, cells pass through an extra-embryonic endoderm (XEN)-like state. Here, we show that these chemically induced XEN-like cells can also be induced to directly reprogram into functional neurons, bypassing the pluripotent state. The induced neurons possess neuron-specific expression profiles, form functional synapses in culture, and further mature after transplantation into the adult mouse brain. Using similar principles, we were also able to induce hepatocyte-like cells from the XEN-like cells. Cells in the induced XEN-like state were readily expandable over at least 20 passages and retained genome stability and lineage specification potential. Our study therefore establishes a multifunctional route for chemical lineage reprogramming and may provide a platform for generating a diverse range of cell types via application of this expandable XEN-like state. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Chemical considerations in severe accident analysis

    International Nuclear Information System (INIS)

    Malinauskas, A.P.; Kress, T.S.

    1988-01-01

    The Reactor Safety Study presented the first systematic attempt to include fission product physicochemical effects in the determination of expected consequences of hypothetical nuclear reactor power plant accidents. At the time, however, the data base was sparse, and the treatment of fission product behavior was not entirely consistent or accurate. Considerable research has since been performed to identify and understand chemical phenomena that can occur in the course of a nuclear reactor accident, and how these phenomena affect fission product behavior. In this report, the current status of our understanding of the chemistry of fission products in severe core damage accidents is summarized and contrasted with that of the Reactor Safety Study

  11. Direct analysis of radionuclides-96 samples simultaneously

    International Nuclear Information System (INIS)

    Kessler, M.J.

    1991-01-01

    Recently, there has been a tremendous interest in two areas of concern in nuclear counting and radioactivity waste disposal. The first is the reduction of radioactive waste, in particular the reduction in the amount of or the development of environmentally safe scintillation cocktails. The second is the development of a simple method of quantitating large numbers of samples (thousands/day) in a short period of time (minutes). These two areas of concern have been addressed with the development of the Matrix 96 direct beta counter. This new instrumental technique is capable of quantitating 96 samples simultaneously in the microplate format (8 x 12, 96 sample) on a solid support WITHOUT the use of any cocktails, vials, and is non-destructive to the sample. The use of this technique for the following biomedical applications, DNA dot blots, cell proliferation (3H thymidine), receptor binding, chromium cytotoxicity assays, and protein assays will be discussed in detail. The data from both the conventional beta and gamma counter will be correlated and compared to the new Matrix 96 direct beta counter. This new technique provides a convenient method of addressing the concerns of reducing radioactive waste and provides a method of quantitating a large number of samples, accurately in a short period of time (96 at a time)

  12. Direct block scheduling technology: Analysis of Avidity

    Directory of Open Access Journals (Sweden)

    Felipe Ribeiro Souza

    Full Text Available Abstract This study is focused on Direct Block Scheduling testing (Direct Multi-Period Scheduling methodology which schedules mine production considering the correct discount factor of each mining block, resulting in the final pit. Each block is analyzed individually in order to define the best target period. This methodology presents an improvement of the classical methodology derived from Lerchs-Grossmann's initial proposition improved by Whittle. This paper presents the differences between these methodologies, specially focused on the algorithms' avidity. Avidity is classically defined by the voracious search algorithms, whereupon some of the most famous greedy algorithms are Branch and Bound, Brutal Force and Randomized. Strategies based on heuristics can accentuate the voracity of the optimizer system. The applied algorithm use simulated annealing combined with Tabu Search. The most avid algorithm can select the most profitable blocks in early periods, leading to higher present value in the first periods of mine operation. The application of discount factors to blocks on the Lerchs-Grossmann's final pit has an accentuated effect with time, and this effect may make blocks scheduled for the end of the mine life unfeasible, representing a trend to a decrease in reported reserves.

  13. Analysis of chemical constituents in medicinal plants of selected ...

    African Journals Online (AJOL)

    Analysis of chemical constituents in medicinal plants of selected districts of Pakhtoonkhwa, Pakistan. I Hussain, R Ullah, J Khan, N Khan, M Zahoor, N Ullah, MuR Khattak, FA Khan, A Baseer, M Khurram ...

  14. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Escalante, Maryana [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Maury, Pascale [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Bruinink, Christiaan M [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Werf, Kees van der [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Olsen, John D [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Timney, John A [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Huskens, Jurriaan [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hunter, C Neil [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Subramaniam, Vinod [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Otto, Cees [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands)

    2008-01-16

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures.

  15. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    International Nuclear Information System (INIS)

    Escalante, Maryana; Maury, Pascale; Bruinink, Christiaan M; Werf, Kees van der; Olsen, John D; Timney, John A; Huskens, Jurriaan; Hunter, C Neil; Subramaniam, Vinod; Otto, Cees

    2008-01-01

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures

  16. Direct synthesis of nanocrystalline oxide powders by wet-chemical techniques

    Directory of Open Access Journals (Sweden)

    Vladimir V. Srdić

    2010-09-01

    Full Text Available In a recent period there is a great need for increasing the knowledge of tailoring the innovative procedures for the synthesis of electroceramic nanopowders and materials with improved quality for specific application. In order to produce electroceramics with desirable microstructure and properties, synthesis of stoichiometric, ultra-fine and agglomerate free powders with narrow size distributions is one of the most important steps. Within this scope, in the present paper we summarize our recent results on direct synthesis of some important perovskites and ferrites nanopowders by wet-chemical techniques.

  17. Empirical direction in design and analysis

    CERN Document Server

    Anderson, Norman H

    2001-01-01

    The goal of Norman H. Anderson's new book is to help students develop skills of scientific inference. To accomplish this he organized the book around the ""Experimental Pyramid""--six levels that represent a hierarchy of considerations in empirical investigation--conceptual framework, phenomena, behavior, measurement, design, and statistical inference. To facilitate conceptual and empirical understanding, Anderson de-emphasizes computational formulas and null hypothesis testing. Other features include: *emphasis on visual inspection as a basic skill in experimental analysis to help student

  18. Chemical analysis of cyanide in cyanidation process: review of methods

    International Nuclear Information System (INIS)

    Nova-Alonso, F.; Elorza-Rodriguez, E.; Uribe-Salas, A.; Perez-Garibay, R.

    2007-01-01

    Cyanidation, the world wide method for precious metals recovery, the chemical analysis of cyanide, is a very important, but complex operation. Cyanide can be present forming different species, each of them with different stability, toxicity, analysis method and elimination technique. For cyanide analysis, there exists a wide selection of analytical methods but most of them present difficulties because of the interference of species present in the solution. This paper presents the different available methods for chemical analysis of cyanide: titration, specific electrode and distillation, giving special emphasis on the interferences problem, with the aim of helping in the interpretation of the results. (Author)

  19. Chemical composition analysis and authentication of whisky.

    Science.gov (United States)

    Wiśniewska, Paulina; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

    2015-08-30

    Whisky (whiskey) is one of the most popular spirit-based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV-Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k-NN and CA, as well as preparation techniques such SPME or SPE. © 2014 Society of Chemical Industry.

  20. Analysis of blood spots for polyfluoroalkyl chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Kayoko; Wanigatunga, Amal A.; Needham, Larry L. [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA (United States); Calafat, Antonia M., E-mail: acalafat@cdc.gov [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA (United States)

    2009-12-10

    Polyfluoroalkyl chemicals (PFCs) have been detected in humans, in the environment, and in ecosystems around the world. The potential for developmental and reproductive toxicities of some PFCs is of concern especially to children's health. In the United States, a sample of a baby's blood, called a 'dried blood spot' (DBS), is obtained from a heel stick within 48 h of a child's birth. DBS could be useful for assessing prenatal exposure to PFCs. We developed a method based on online solid phase extraction coupled with high performance liquid chromatography-isotope dilution tandem mass spectrometry for measuring four PFCs in DBS, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate, perfluorooctanoate (PFOA), and perfluorononanoate. The analytical limits of detection using one whole DBS ({approx}75 {mu}L of blood) were <0.5 ng mL{sup -1}. To validate the method, we analyzed 98 DBS collected in May 2007 in the United States. PFOS and PFOA were detected in all DBS at concentrations in the low ng mL{sup -1} range. These data suggest that DBS may be a suitable matrix for assessing perinatal exposure to PFCs, but additional information related to sampling and specimen storage is needed to demonstrate the utility of these measures for assessing exposure.

  1. Droplet microfluidics in (bio) chemical analysis

    Czech Academy of Sciences Publication Activity Database

    Basova, E. Y.; Foret, František

    2015-01-01

    Roč. 140, č. 1 (2015), s. 22-38 ISSN 0003-2654 R&D Projects: GA ČR(CZ) GBP206/12/G014 Institutional support: RVO:68081715 Keywords : droplet chemistry * bio analysis * microfluidics * protein Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.033, year: 2015

  2. Chemical aspects of nuclear methods of analysis

    International Nuclear Information System (INIS)

    1985-01-01

    This final report includes papers which fall into three general areas: development of practical pre-analysis separation techniques, uranium/thorium separation from other elements for analytical and processing operations, and theory and mechanism of separation techniques. A separate abstract was prepared for each of the 9 papers

  3. Chemical composition, antimicrobial activity, proximate analysis and ...

    African Journals Online (AJOL)

    Detarium senegalense JF Gmelin (Caesalpiniaceae), commonly known as tallow tree, is used traditionally for the treatment of bronchitis, pneumonia, internal complaints and skin diseases in Tropical Africa. The seed is used as a soup thickener in Eastern Nigeria. Analysis of the petroleum ether extract of the seeds with ...

  4. Direct chemical oxidation: a non-thermal technology for the destruction of organic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, G.B.; Cooper, J. F.; Lewis, P. R.; Adamson, M. G.

    1998-02-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment and chemical demilitarization and decontamination at LLNL since 1992, and is applicable to the destruction of virtually all solid or liquid organics, including: chlorosolvents, oils and greases, detergents, organic-contaminated soils or sludges, explosives, chemical and biological warfare agents, and PCB's. [1-15] The process normally operates at 80-100 C, a heating requirement which increases the difficulty of surface decontamination of large objects or, for example, treatment of a wide area contaminated soil site. The driver for DCO work in FY98 was thus to investigate the use of catalysts to demonstrate the effectiveness of the technology for organics destruction at temperatures closer to ambient. In addition, DCO is at a sufficiently mature stage of development that technology transfer to a commercial entity was a logical next step, and was thus included in FY98 tasks.

  5. Safety- and Risk Analysis Activities in Chemical Industry in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Kozine, Igor; Duijm, Nijs Jan; Lauridsen Kurt [Risoe National Laboratory, Roskilde (Denmark). Systems Analysis Department

    2001-07-01

    The current paper gives an overview of the legislation and the methods used in safety and risk management in the chemical industry within Europe and in particular within the European Union. The paper is based on a report that has been written for the SOS-1 project under the Nordic nuclear safety research (NKS). Safety- and risk-related matters in the process industry, in particular, in chemical, within the EU are subject to consideration at three levels: (1) EU legislation, (2) European/intemational standardisation, and (3) socio-economic analysis. EC Directives define the 'essential requirements', e.g., protection of health and safety, that must be fulfilled when goods are placed on the market or some industry is put into operation. The European standards bodies (CEN, CENELEC and ETSI) have the task of establishing the corresponding technical specifications, meeting the essential requirements of the Directives, compliance with which will provide a presumption of conformity with the essential requirements. Such specifications are referred to as 'harmonised standards'. Compliance with harmonised standards remains voluntary, and manufacturers are free to choose any other technical solution that provides compliance with the essential requirements. This view is stated in the 'New Approach' to technical harmonisation and standardisation (details can be found on the web page: http://europe.eu.int/comm/enterprise/newapproach/standardization/index .html). Standardisation as well as the regulation of technical risks is increasingly being undertaken at European or international level. The European legislator limits its role to the affirmation of overall objectives, and leaves it to the economic players to draw up the technical procedures and standards to specify in detail the ways and means of attaining them. Many countries have introduced requirements that new legislation and/or administrative regulations be subject to socio-economic analysis

  6. Flow-dependent directional growth of carbon nanotube forests by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeongkeun; Park, Young Chul; Chun, Kyoung-Yong; Kim, Young-Jin; Choi, Jae-Boong [School of Mechanical Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Kim, Keun Soo; Kang, Junmo; Hong, Byung Hee [SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Boo, Jin-Hyo, E-mail: byunghee@skku.edu, E-mail: boong33@skku.edu [Department of Chemistry, RIAN and Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

    2011-03-04

    We demonstrated that the structural formation of vertically aligned carbon nanotube (CNT) forests is primarily affected by the geometry-related gas flow, leading to the change of growth directions during the chemical vapor deposition (CVD) process. By varying the growing time, flow rate, and direction of the carrier gas, the structures and the formation mechanisms of the vertically aligned CNT forests were carefully investigated. The growth directions of CNTs are found to be highly dependent on the nonlinear local gas flows induced by microchannels. The angle of growth significantly changes with increasing gas flows perpendicular to the microchannel, while the parallel gas flow shows almost no effect. A computational fluid dynamics (CFD) model was employed to explain the flow-dependent growth of CNT forests, revealing that the variation of the local pressure induced by microchannels is an important parameter determining the directionality of the CNT growth. We expect that the present method and analyses would provide useful information to control the micro- and macrostructures of vertically aligned CNTs for various structural/electrical applications.

  7. Flow-dependent directional growth of carbon nanotube forests by chemical vapor deposition

    International Nuclear Information System (INIS)

    Kim, Hyeongkeun; Park, Young Chul; Chun, Kyoung-Yong; Kim, Young-Jin; Choi, Jae-Boong; Kim, Keun Soo; Kang, Junmo; Hong, Byung Hee; Boo, Jin-Hyo

    2011-01-01

    We demonstrated that the structural formation of vertically aligned carbon nanotube (CNT) forests is primarily affected by the geometry-related gas flow, leading to the change of growth directions during the chemical vapor deposition (CVD) process. By varying the growing time, flow rate, and direction of the carrier gas, the structures and the formation mechanisms of the vertically aligned CNT forests were carefully investigated. The growth directions of CNTs are found to be highly dependent on the nonlinear local gas flows induced by microchannels. The angle of growth significantly changes with increasing gas flows perpendicular to the microchannel, while the parallel gas flow shows almost no effect. A computational fluid dynamics (CFD) model was employed to explain the flow-dependent growth of CNT forests, revealing that the variation of the local pressure induced by microchannels is an important parameter determining the directionality of the CNT growth. We expect that the present method and analyses would provide useful information to control the micro- and macrostructures of vertically aligned CNTs for various structural/electrical applications.

  8. Chemical analysis developments for fusion materials studies

    International Nuclear Information System (INIS)

    McCown, J.J.; Baldwin, D.L.; Keough, R.F.; Van der Cook, B.P.

    1985-04-01

    Several projects at Hanford under the management of the Westinghouse Hanford Company have involved research and development (R and D) on fusion materials. They include work on the Fusion Materials Irradiation Test Facility and its associated Experimental Lithium System; testing of irradiated lithium compounds as breeding materials; and testing of Li and Li-Pb alloy reactions with various atmospheres, concrete, and other reactor materials for fusion safety studies. In the course of these projects, a number of interesting and challenging analytical chemistry problems were encountered. They include sampling and analysis of lithium while adding and removing elements of interest; sampling, assaying and compound identification efforts on filters, aerosol particles and fire residues; development of dissolution and analysis techniques for measuring tritium and helium in lithium ceramics including oxides, aluminates, silicates and zirconates. An overview of the analytical chemistry development problems plus equipment and procedures used will be presented

  9. Chemical analysis of rare earth elements

    International Nuclear Information System (INIS)

    Tsukahara, Ryoichi; Sakoh, Takefumi; Nagai, Iwao

    1994-01-01

    Recently attention has been paid to ICP-AES or ICP-MS, and the reports on the analysis of rare earth elements by utilizing these methods continue to increase. These reports have become to take about 30% of the reports on rare earth analysis, and this is because these methods are highly sensitive to rare earth elements, and also these methods have spread widely. In ICP-AES and ICP-MS, mostly solution samples are measured, therefore, solids must be made into solution. At the time of quantitatively determining the rare earth elements of low concentration, separation and concentration are necessary. Referring to the literatures reported partially in 1990 and from 1991 to 1993, the progress of ICP-AES and ICP-MS is reported. Rare earth oxides and the alloys containing rare earth elements are easily decomposed with acids, but the decomposition of rocks is difficult, and its method is discussed. The separation of the rare earth elements from others in geochemical samples, cation exchange process is frequently utilized. Also solvent extraction process has been studied. For the separation of rare earth elements mutually, chromatography is used. The spectral interference in spectral analysis was studied. The comparison of these methods with other methods is reported. (K.I)

  10. Direct identification of fungi using image analysis

    DEFF Research Database (Denmark)

    Dørge, Thorsten Carlheim; Carstensen, Jens Michael; Frisvad, Jens Christian

    1999-01-01

    Filamentous fungi have often been characterized, classified or identified with a major emphasis on macromorphological characters, i.e. the size, texture and color of fungal colonies grown on one or more identification media. This approach has been rejcted by several taxonomists because of the sub......Filamentous fungi have often been characterized, classified or identified with a major emphasis on macromorphological characters, i.e. the size, texture and color of fungal colonies grown on one or more identification media. This approach has been rejcted by several taxonomists because...... of the subjectivity in the visual evaluation and quantification (if any)of such characters and the apparent large variability of the features. We present an image analysis approach for objective identification and classification of fungi. The approach is exemplified by several isolates of nine different species...... of the genus Penicillium, known to be very difficult to identify correctly. The fungi were incubated on YES and CYA for one week at 25 C (3 point inoculation) in 9 cm Petri dishes. The cultures are placed under a camera where a digital image of the front of the colonies is acquired under optimal illumination...

  11. Advanced chemical analysis service for elements, radionuclides and phases

    International Nuclear Information System (INIS)

    Sansoni, B.

    1986-01-01

    A review is given on the structure, organisation and performance of the chemical analysis service of the Central Department for Chemical Analysis at the Kernforschungsanlage Juelich GmbH. The research and development programs together with the infrastructure of the Centre afford to analyse almost all stable elements of the periodical table in almost any material. The corresponding chemical analysis service has been organized according to a new modular system of analytical steps. According to this, the most complicated and, therefore, most general case of an analytical scheme for element and radionuclide analysis in any type of material can be differentiated into about 14 different steps, the modules. They are more or less independent of the special problem. The laboratory is designed and organized according to these steps. (orig./PW) [de

  12. New analytical techniques for cuticle chemical analysis

    International Nuclear Information System (INIS)

    Schulten, H.R.

    1994-01-01

    1) The analytical methodology of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and direct pyrolysis-mass spectrometry (Py-MS) using soft ionization techniques by high electric fields (FL) are briefly described. Recent advances of Py-GC/MS and Py-FIMS for the analyses of complex organic matter such as plant materials, humic substances, dissolved organic matter in water (DOM) and soil organic matter (SOM) in agricultural and forest soils are given to illustrate the potential and limitations of the applied methods. 2) Novel applications of Py-GC/MS and Py-MS in combination with conventional analytical data in an integrated, chemometric approach to investigate the dynamics of plant lipids are reported. This includes multivariate statistical investigations on maturation, senescence, humus genesis, and environmental damages in spruce ecosystems. 3) The focal point is the author's integrated investigations on emission-induced changes of selected conifer plant constituents. Pattern recognition of Py-MS data of desiccated spruce needles provides a method for distinguishing needles damaged in different ways and determining the cause. Spruce needles were collected from both controls and trees treated with sulphur dioxide (acid rain), nitrogen dioxide, and ozone under controlled conditions. Py-MS and chemometric data evaluation are employed to characterize and classify leaves and their epicuticular waxes. Preliminary mass spectrometric evaluations of isolated cuticles of different plants such as spruce, ivy, holly, and philodendron, as well as ivy cuticles treated in vivo with air pollutants such as surfactants and pesticides are given. (orig.)

  13. Development of sodium droplet combustion analysis methodology using direct numerical simulation in 3-dimensional coordinate (COMET)

    International Nuclear Information System (INIS)

    Okano, Yasushi; Ohira, Hiroaki

    1998-08-01

    In the early stage of sodium leak event of liquid metal fast breeder reactor, LMFBR, liquid sodium flows out from a piping, and ignition and combustion of liquid sodium droplet might occur under certain environmental condition. Compressible forced air flow, diffusion of chemical species, liquid sodium droplet behavior, chemical reactions and thermodynamic properties should be evaluated with considering physical dependence and numerical connection among them for analyzing combustion of sodium liquid droplet. A direct numerical simulation code was developed for numerical analysis of sodium liquid droplet in forced convection air flow. The numerical code named COMET, 'Sodium Droplet COmbustion Analysis METhodology using Direct Numerical Simulation in 3-Dimensional Coordinate'. The extended MAC method was used to calculate compressible forced air flow. Counter diffusion among chemical species is also calculated. Transport models of mass and energy between droplet and surrounding atmospheric air were developed. Equation-solving methods were used for computing multiphase equilibrium between sodium and air. Thermodynamic properties of chemical species were evaluated using dynamic theory of gases. Combustion of single sphere liquid sodium droplet in forced convection, constant velocity, uniform air flow was numerically simulated using COMET. Change of droplet diameter with time was closely agree with d 2 -law of droplet combustion theory. Spatial distributions of combustion rate and heat generation and formation, decomposition and movement of chemical species were analyzed. Quantitative calculations of heat generation and chemical species formation in spray combustion are enabled for various kinds of environmental condition by simulating liquid sodium droplet combustion using COMET. (author)

  14. Chemical kinetic functional sensitivity analysis: Elementary sensitivities

    International Nuclear Information System (INIS)

    Demiralp, M.; Rabitz, H.

    1981-01-01

    Sensitivity analysis is considered for kinetics problems defined in the space--time domain. This extends an earlier temporal Green's function method to handle calculations of elementary functional sensitivities deltau/sub i//deltaα/sub j/ where u/sub i/ is the ith species concentration and α/sub j/ is the jth system parameter. The system parameters include rate constants, diffusion coefficients, initial conditions, boundary conditions, or any other well-defined variables in the kinetic equations. These parameters are generally considered to be functions of position and/or time. Derivation of the governing equations for the sensitivities and the Green's funciton are presented. The physical interpretation of the Green's function and sensitivities is given along with a discussion of the relation of this work to earlier research

  15. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Matthew W. [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  16. Avogadro: an advanced semantic chemical editor, visualization, and analysis platform

    Directory of Open Access Journals (Sweden)

    Hanwell Marcus D

    2012-08-01

    Full Text Available Abstract Background The Avogadro project has developed an advanced molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible, high quality rendering, and a powerful plugin architecture. Typical uses include building molecular structures, formatting input files, and analyzing output of a wide variety of computational chemistry packages. By using the CML file format as its native document type, Avogadro seeks to enhance the semantic accessibility of chemical data types. Results The work presented here details the Avogadro library, which is a framework providing a code library and application programming interface (API with three-dimensional visualization capabilities; and has direct applications to research and education in the fields of chemistry, physics, materials science, and biology. The Avogadro application provides a rich graphical interface using dynamically loaded plugins through the library itself. The application and library can each be extended by implementing a plugin module in C++ or Python to explore different visualization techniques, build/manipulate molecular structures, and interact with other programs. We describe some example extensions, one which uses a genetic algorithm to find stable crystal structures, and one which interfaces with the PackMol program to create packed, solvated structures for molecular dynamics simulations. The 1.0 release series of Avogadro is the main focus of the results discussed here. Conclusions Avogadro offers a semantic chemical builder and platform for visualization and analysis. For users, it offers an easy-to-use builder, integrated support for downloading from common databases such as PubChem and the Protein Data Bank, extracting chemical data from a wide variety of formats, including computational chemistry output, and native, semantic support for the CML file format

  17. Handbook of Basic Tables for Chemical Analysis. Final report

    International Nuclear Information System (INIS)

    Bruno, T.J.; Svoronos, P.D.N.

    1988-04-01

    This work began as a slim booklet prepared by one of the authors (TJB) to accompany a course on chemical instrumentation presented at the National Bureau of Standards, Boulder Laboratories. The booklet contained tables on chromatography, spectroscopy, and chemical (wet) methods, and was intended to provide the students with enough basic data to design their own analytical methods and procedures. Shortly thereafter, with the co-authorship of Prof. Paris D. N. Svoronos, it was expanded into a more-extensive compilation entitled Basic Tables for Chemical Analysis, published as National Bureau of Standards Technical Note 1096. That work has now been expanded and updated into the present body of tables. Although there have been considerable changes since the first version of these tables, the aim has remained essentially the same. The authors have tried to provide a single source of information for those practicing scientists and research students who must use various aspects of chemical analysis in their work. In this respect, it is geared less toward the researcher in analytical chemistry than to those practitioners in other chemical disciplines who must have routine use of chemical analysis

  18. Airborne chemistry: acoustic levitation in chemical analysis.

    Science.gov (United States)

    Santesson, Sabina; Nilsson, Staffan

    2004-04-01

    This review with 60 references describes a unique path to miniaturisation, that is, the use of acoustic levitation in analytical and bioanalytical chemistry applications. Levitation of small volumes of sample by means of a levitation technique can be used as a way to avoid solid walls around the sample, thus circumventing the main problem of miniaturisation, the unfavourable surface-to-volume ratio. Different techniques for sample levitation have been developed and improved. Of the levitation techniques described, acoustic or ultrasonic levitation fulfils all requirements for analytical chemistry applications. This technique has previously been used to study properties of molten materials and the equilibrium shape()and stability of liquid drops. Temperature and mass transfer in levitated drops have also been described, as have crystallisation and microgravity applications. The airborne analytical system described here is equipped with different and exchangeable remote detection systems. The levitated drops are normally in the 100 nL-2 microL volume range and additions to the levitated drop can be made in the pL-volume range. The use of levitated drops in analytical and bioanalytical chemistry offers several benefits. Several remote detection systems are compatible with acoustic levitation, including fluorescence imaging detection, right angle light scattering, Raman spectroscopy, and X-ray diffraction. Applications include liquid/liquid extractions, solvent exchange, analyte enrichment, single-cell analysis, cell-cell communication studies, precipitation screening of proteins to establish nucleation conditions, and crystallisation of proteins and pharmaceuticals.

  19. Development of chemical analysis techniques: pt. 3

    International Nuclear Information System (INIS)

    Kim, K.J.; Chi, K.Y.; Choi, G.C.

    1981-01-01

    For the purpose of determining trace rare earths a spectrofluorimetric method has been studied. Except Ce and Tb, the fluorescence intensities are not enough to allow satisfactory analysis. Complexing agents such as tungstate and hexafluoroacetylacetone should be employed to increase fluorescence intensities. As a preliminary experiment for the separation of individual rare earth element and uranium, the distribution coefficient, % S here, are obtained on the Dowex 50 W against HCl concentration by a batch method. These % S data are utilized to obtain elution curves. The % S data showed a minimum at around 4 M HCl. To understand this previously known phenomenon the adsorption of Cl - on Dowex 50 W is examined as a function of HCl concentration and found to be decreasing while % S of rare earths increasing. It is interpreted that Cl - and rare earth ions are moved into the resin phase separately and that the charge and the charge densities of these ions are responsible for the different % S curves. Dehydration appears to play an important role in the upturn of the % S curves at higher HCl concentrations

  20. Direct Analysis of Samples of Various Origin and Composition Using Specific Types of Mass Spectrometry.

    Science.gov (United States)

    Byliński, Hubert; Gębicki, Jacek; Dymerski, Tomasz; Namieśnik, Jacek

    2017-07-04

    One of the major sources of error that occur during chemical analysis utilizing the more conventional and established analytical techniques is the possibility of losing part of the analytes during the sample preparation stage. Unfortunately, this sample preparation stage is required to improve analytical sensitivity and precision. Direct techniques have helped to shorten or even bypass the sample preparation stage; and in this review, we comment of some of the new direct techniques that are mass-spectrometry based. The study presents information about the measurement techniques using mass spectrometry, which allow direct sample analysis, without sample preparation or limiting some pre-concentration steps. MALDI - MS, PTR - MS, SIFT - MS, DESI - MS techniques are discussed. These solutions have numerous applications in different fields of human activity due to their interesting properties. The advantages and disadvantages of these techniques are presented. The trends in development of direct analysis using the aforementioned techniques are also presented.

  1. Methods of direct (non-chromatographic) quantification of body metabolites utilizing chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Mee, J.M.L.

    1978-01-01

    For quantitative determination of known metabolites from the biological sample by direct chemical ionization mass spectrometry (CI-MS), the method of internal standard using stable isotopically labelled analogs appears to be the method of choice. In the case where stable isotope ratio determinations could not be applied, and alternative quantification can be achieved using non-labelled external or internal standards and a calibration curve (sum of peak height per a given number of scans versus concentration). The technique of computer monitoring permits display and plotting of ion current profiles (TIC and SIC) or spectra per a given number of scans or a given range of mass per charge. Examples are given in areas of clinical application and the quantitative data show very good agreement with the conventional chromatographic measurements. (Auth.)

  2. Direct Growth of Graphene on Silicon by Metal-Free Chemical Vapor Deposition

    Science.gov (United States)

    Tai, Lixuan; Zhu, Daming; Liu, Xing; Yang, Tieying; Wang, Lei; Wang, Rui; Jiang, Sheng; Chen, Zhenhua; Xu, Zhongmin; Li, Xiaolong

    2018-06-01

    The metal-free synthesis of graphene on single-crystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed, single-crystal silicon substrate using metal-free, ambient-pressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates. [Figure not available: see fulltext.

  3. Four chemical trends will shape the next decade's directions in Perfluoroalkyl and Polyfluoroalkyl substances research

    Science.gov (United States)

    Kotthoff, Matthias; Bücking, Mark

    2018-04-01

    Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS.This is a result of an incomplete understanding of the range of compounds that they comprise in differing products. There are analytical uncertainties identifying PFAS and estimating the concentrations of the total PFAS loadindividual molecules remain unknown. There are four major trends from the chemical perspective that will shape PFAS research for the next decade. 1.Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility. 2.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern. 3.Increase in structural diversity of existing PFAS molecules: Introduction of e.g. hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules. 4. Unknown “Dark Matter”: The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown. These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.

  4. Four Chemical Trends Will Shape the Next Decade's Directions in Perfluoroalkyl and Polyfluoroalkyl Substances Research.

    Science.gov (United States)

    Kotthoff, Matthias; Bücking, Mark

    2018-01-01

    Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS. This is a result of an incomplete understanding of the range of compounds that they comprise in differing products. There are analytical uncertainties identifying PFAS and estimating the concentrations of the total PFAS load individual molecules remain unknown. There are four major trends from the chemical perspective that will shape PFAS research for the next decade. Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern.Increase in structural diversity of existing PFAS molecules: Introduction of e.g., hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules.Unknown "Dark Matter": The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown. These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.

  5. Analysis of foreign direct investment in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Marcela Domesová

    2011-01-01

    Full Text Available The foreign direct investments are joined with the process of world globalisation. Foreign direct investments are carried out especially by multinational companies. The basic forms of the foreign direct investments are “greenfield” investments and “brownfield“ investments in the form of the privatization. The Czech Republic has shown mass inflow of foreign direct investments since 1998. The aim of the paper is to evaluate the inflow of foreign direct investments in the context of the balance of payments and the evaluation their impact on the outside economic equilibrium and gross value added in the Czech Republic. The subject of the analysis is the identification of the most important factors of foreign direct investments inflow and the classification of foreign direct investments inflow from the point of view of branches and technological intensity of production as well. The aim is fulfilled by analysis of selected indicators of the balance of payments, analysis of gross value added and international comparison of foreign direct investments inflow in countries of Visegrad Group. The results show the part of privatization in foreign capital inflow, increasing import intensity and export efficiency linked with foreign direct investments. The results are subject of research focused on the process of world globalisation and regional development.

  6. Taxation and Gender Equity: A Comparative Analysis of Direct and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-06-10

    Jun 10, 2010 ... Taxation and Gender Equity: A Comparative Analysis of Direct and Indirect Taxes in Developing and Developed Countries ... This highly original book is essential reading for everyone concerned with equality in taxation.

  7. Comparative analysis of direct and indirect property investment ...

    African Journals Online (AJOL)

    Comparative analysis of direct and indirect property investment returns in Abuja. ... in property shares is more risky than commercial property due to the risk ... of the stock market, it was discovered that there is a strong positive relationship ...

  8. ANALYSIS OF SAMPLES FROM TANK 5F CHEMICAL CLEANING

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-03-07

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. The conclusions from this work are: (1) With the exception of iron, the dissolution of sludge components from Tank 5F agreed with results from the actual waste demonstration performed in 2007. The fraction of iron removed from Tank 5F by chemical cleaning was significantly less than the fraction removed in the SRNL demonstrations. The likely cause of this difference is the high pH following the first oxalic acid strike. (2) Most of the sludge mass remaining in the tank is iron and nickel. (3) The remaining sludge contains approximately 26 kg of barium, 37 kg of chromium, and 37 kg of mercury. (4) Most of the radioactivity remaining in the residual material is beta emitters and {sup 90}Sr. (5) The chemical cleaning removed more than {approx} 90% of the uranium isotopes and {sup 137}Cs. (6) The chemical cleaning removed {approx} 70% of the neptunium, {approx} 83% of the {sup 90}Sr, and {approx} 21% of the {sup 60}Co. (7) The chemical cleaning removed less than 10% of the plutonium, americium, and curium isotopes. (8) The chemical cleaning removed more than 90% of the aluminium, calcium, and sodium from the tank. (9) The cleaning operations removed 61% of lithium, 88% of non-radioactive strontium, and 65% of zirconium. The {sup 90}Sr and non-radioactive strontium were

  9. Direct synthesis of hydrophobic graphene-based nanosheets via chemical modification of exfoliated graphene oxide.

    Science.gov (United States)

    Wang, Jigang; Wang, Yongsheng; He, Dawei; Liu, Zhiyong; Wu, Hongpeng; Wang, Haiteng; Zhao, Yu; Zhang, Hui; Yang, Bingyang; Xu, Haiteng; Fu, Ming

    2012-08-01

    Hydrophobic graphene-based material at the nanoscale was prepared by treatment of exfoliated graphene oxide with organic isocyanates. The lipophilic modified graphene oxide (LMGO) can then be exfoliated into the functionalized graphene nanoplatelets that can form a stable dispersion in polar aprotic solvents. AFM image shows the thickness of LMGO is approximately 1 nm. Characterization of LMGO by elemental analysis suggested that the chemical treatment results in the functionalization of the carboxyl and hydroxyl groups in GO via formation of amides and carbamate esters, respectively. The degree of GO functionalization can be controlled via either the reactivity of the isocyanate or the reaction time. Then we investigated the thermal properties of the SPFGraphene by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the TGA curve shows a greater weight loss of approximately 20% occurred indicating removal of functional groups from the LMGO sheets and an obvious exothermic peak at 176 degrees can be observed from 150 to 250 degrees. We also compared the structure of graphene oxide with the structure of chemical treated graphene oxide by FT-IR spectroscopy. The morphology and microstructure of the LMGO nanosheets were also characterized by SEM and XRD. Graphene can be used to fabricate a wide range of simple electronic devices such as field-effect transistors, resonators, quantum dots and some other extensive industrial manufacture such as super capacitor, li ion battery, solar cells and even transparent electrodes in device applications.

  10. Direct analysis of traditional Chinese medicines by mass spectrometry.

    Science.gov (United States)

    Wong, Melody Yee-Man; So, Pui-Kin; Yao, Zhong-Ping

    2016-07-15

    Analysis of traditional Chinese medicines (TCMs) plays important roles in quality control of TCMs and understanding their pharmacological effects. Mass spectrometry (MS) is a technique of choice for analysis of TCMs due to its superiority in speed, sensitivity and specificity. However, conventional MS analysis of TCMs typically requires extensive sample pretreatment and chromatographic separation, which could be time-consuming and laborious, prior to the analysis. The expanding usage of TCMs worldwide demands development of rapid, cost-effective and reliable methods for analysis of TCMs. In recent years, new sample preparation and ionization techniques have been developed to enable direct analysis of TCMs by MS, significantly reducing the analysis time and cost. In this review, various MS-based techniques, mainly including ambient ionization-MS and MALDI-MS based techniques, applied for direct analysis of TCMs are summarized and their applicability and future prospects are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. The chemical basis of DNA damage by the direct pathway of ionizing radiation

    International Nuclear Information System (INIS)

    Sharma, Kiran Kumar K.

    2013-01-01

    Free radicals in living system has been implicated as playing a major role in the etiology of variety of diseases. The mechanism of free radicals in vivo involves predominantly the reaction with the DNA, producing different types of damage to the DNA. These lesions induced to the DNA could lead to mutation and even cell death. Radiolysis techniques, which uses ionizing radiation has proven to be one of the most advanced and excellent tool for studying the free radical reaction mechanisms as it can produce a host of well characterized free radicals. The effects of ionizing radiation on DNA have been studied for many years. Ionizing radiation interacts with DNA in vivo by two pathways, direct and indirect. The indirect accounts for 50-60% while the direct effect accounts for 40-50%. The chemical mechanism of the former reaction arising mainly from the reactive species produced by radiolysis of water has been extensively studied, however with respect to the later pathway, which creates holes and electrons to the DNA molecule using DNA films and crystals is an active area of research as both the pathways plays important roles in DNA damage in vivo particularly in chromosomal DNA which are tightly bound with histones and compartmentalized

  12. Direct analysis of biological samples by total reflection X-ray fluorescence

    International Nuclear Information System (INIS)

    Lue M, Marco P.; Hernandez-Caraballo, Edwin A.

    2004-01-01

    The technique of total reflection X-ray fluorescence (TXRF) is well suited for the direct analysis of biological samples due to the low matrix interferences and simultaneous multi-element nature. Nevertheless, biological organic samples are frequently analysed after digestion procedures. The direct determination of analytes requires shorter analysis time, low reactive consumption and simplifies the whole analysis process. On the other hand, the biological/clinical samples are often available in minimal amounts and routine studies require the analysis of large number of samples. To overcome the difficulties associated with the analysis of organic samples, particularly of solid ones, different procedures of sample preparation and calibration to approach the direct analysis have been evaluated: (1) slurry sampling, (2) Compton peak standardization, (3) in situ microwave digestion, (4) in situ chemical modification and (5) direct analysis with internal standardization. Examples of analytical methods developed by our research group are discussed. Some of them have not been previously published, illustrating alternative strategies for coping with various problems that may be encountered in the direct analysis by total reflection X-ray fluorescence spectrometry

  13. Potential application of ecological models in the European environmental risk assessment of chemicals. I. Review of protection goals in EU directives and regulations.

    Science.gov (United States)

    Hommen, Udo; Baveco, J M Hans; Galic, Nika; van den Brink, Paul J

    2010-07-01

    Several European directives and regulations address the environmental risk assessment of chemicals. We used the protection of freshwater ecosystems against plant protection products, biocidal products, human and veterinary pharmaceuticals, and other chemicals and priority substances under the Water Framework Directive as examples to explore the potential of ecological effect models for a refined risk assessment. Our analysis of the directives, regulations, and related guidance documents lead us to distinguish the following 5 areas for the application of ecological models in chemical risk assessment: 1) Extrapolation of organism-level effects to the population level: The protection goals are formulated in general terms, e.g., avoiding "unacceptable effects" or "adverse impact" on the environment or the "viability of exposed species." In contrast, most of the standard ecotoxicological tests provide data only on organism-level endpoints and are thus not directly linked to the protection goals which focus on populations and communities. 2) Extrapolation of effects between different exposure profiles: Especially for plant protection products, exposure profiles can be very variable and impossible to cover in toxicological tests. 3) Extrapolation of recovery processes: As a consequence of the often short-term exposures to plant protection products, the risk assessment is based on the community recovery principle. On the other hand, assessments under the other directives assume a more or less constant exposure and are based on the ecosystem threshold principle. 4) Analysis and prediction of indirect effects: Because effects on 1 or a few taxa might have consequences on other taxa that are not directly affected by the chemical, such indirect effects on communities have to be considered. 5) Prediction of bioaccumulation within food chains: All directives take the possibility of bioaccumulation, and thus secondary poisoning within the food chain, into account. (c) 2010 SETAC.

  14. Conversion of metallurgical coke and coal using a Coal Direct Chemical Looping (CDCL) moving bed reactor

    International Nuclear Information System (INIS)

    Luo, Siwei; Bayham, Samuel; Zeng, Liang; McGiveron, Omar; Chung, Elena; Majumder, Ankita; Fan, Liang-Shih

    2014-01-01

    Highlights: • Accumulated more than 300 operation hours were accomplished for the moving bed reducer reactor. • Different reactor operation variables were investigated with optimal conditions identified. • High conversions of sub-bituminous coal and bituminous coal were achieved without flow problems. • Co-current and counter-current contact modes were tested and their applicability was discussed. - Abstract: The CLC process has the potential to be a transformative commercial technology for a carbon-constrained economy. The Ohio State University Coal Direct Chemical Looping (CDCL) process directly converts coal, eliminating the need for a coal gasifier oran air separation unit (ASU). Compared to other solid-fuel CLC processes, the CDCL process is unique in that it consists of a countercurrent moving bed reducer reactor. In the proposed process, coal is injected into the middle of the moving bed, whereby the coal quickly heats up and devolatilizes, splitting the reactor roughly into two sections with no axial mixing. The top section consists of gaseous fuel produced from the coal volatiles, and the bottom section consists of the coal char mixed with the oxygen carrier. A bench-scale moving bed reactor was used to study the coal conversion with CO 2 as the enhancing gas. Initial tests using metallurgical cokefines as feedstock were conducted to test the effects of operational variables in the bottom section of the moving bed reducer, e.g., reactor temperature, oxygen carrier to char ratio, enhancer gas CO 2 flow rate, and oxygen carrier flow rates. Experiments directly using coal as the feedstock were subsequently carried out based on these test results. Powder River Basin (PRB) coal and Illinois #6 coal were tested as representative sub-bituminous and bituminous coals, respectively. Nearly complete coal conversion was achieved using composite iron oxide particles as the oxygen carriers without any flow problems. The operational results demonstrated that a

  15. Proton magnetic resonance chemical shift imaging (1H CSI)-directed stereotactic biopsy

    International Nuclear Information System (INIS)

    Son, B.-C.; Kim, B.-C.; Kang, J.-K.; Choi, B.-G.; Kim, E.-N.; Baik, H.-M.; Choe, B.-Y.; Naruse, S.

    2001-01-01

    Introduction. To add metabolic information during stereotactic biopsy target selection, the authors adopted proton chemical shift imaging ( 1 H CSI)-directed stereotactic biopsy. Currently, proton single voxel spectroscopy (SVS) technique has been reported in stereotactic biopsy. We performed 1 H CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, and evaluated the pathological results. Patients and Method. The 1 H CSI-directed stereotactic biopsy was performed in four patients. 1 H CSI and conventional Gd-enhancement stereotactic MRI were performed simultaneously after the fitting of a stereotactic frame. After reconstructing the metabolic maps of N-acetylaspartate (NAA)/phosphocreatine (Cr), phosphocholine (Cho)/Cr, and Lactate/Cr ratios, focal areas of increased Cho/Cr ratio and Lac/Cr ratios were selected as target sites in the stereotactic MR images. Result. 1 H CSI is possible with the stereotactic headframe in place. No difficulty was experienced performing 1 H CSI or making a diagnosis. Pathological samples taken from areas of increased Cho/Cr ratios and decreased NAA/Cr ratios provided information upon increased cellularity, mitoses and cellular atypism, and facilitated diagnosis. Pathological samples taken from areas of increased Lac/ Cr ratio snowed predominant feature of necrosis. Conclusion. 1 H CSI was feasible with the stereotactic headframe in place. The final pathological results obtained were concordant with the local metabolic information from 1 H CSI. We believe that 1 H CSI-directed stereotactic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting. (author)

  16. Modular verification of chemical reaction network encodings via serializability analysis

    Science.gov (United States)

    Lakin, Matthew R.; Stefanovic, Darko; Phillips, Andrew

    2015-01-01

    Chemical reaction networks are a powerful means of specifying the intended behaviour of synthetic biochemical systems. A high-level formal specification, expressed as a chemical reaction network, may be compiled into a lower-level encoding, which can be directly implemented in wet chemistry and may itself be expressed as a chemical reaction network. Here we present conditions under which a lower-level encoding correctly emulates the sequential dynamics of a high-level chemical reaction network. We require that encodings are transactional, such that their execution is divided by a “commit reaction” that irreversibly separates the reactant-consuming phase of the encoding from the product-generating phase. We also impose restrictions on the sharing of species between reaction encodings, based on a notion of “extra tolerance”, which defines species that may be shared between encodings without enabling unwanted reactions. Our notion of correctness is serializability of interleaved reaction encodings, and if all reaction encodings satisfy our correctness properties then we can infer that the global dynamics of the system are correct. This allows us to infer correctness of any system constructed using verified encodings. As an example, we show how this approach may be used to verify two- and four-domain DNA strand displacement encodings of chemical reaction networks, and we generalize our result to the limit where the populations of helper species are unlimited. PMID:27325906

  17. Physico-chemical analysis and sensory evaluation of bread ...

    African Journals Online (AJOL)

    This study carried out the physico-chemical analysis and sensory evaluation of bread produced using different indigenous yeast isolates in order to offer an insight into the overall quality of the bread. Four (4) different yeast species were isolated from sweet orange, pineapple and palm wine. The yeasts were characterized ...

  18. Chemical and antimicrobial analysis of husk fiber aqueous extract ...

    African Journals Online (AJOL)

    Chemical and antimicrobial analysis of husk fiber aqueous extract from Cocos nucifera L. Davi Oliveira e Silva, Gabriel Rocha Martins, Antônio Jorge Ribeiro da Silva, Daniela Sales Alviano, Rodrigo Pires Nascimento, Maria Auxiliadora Coelho Kaplan, Celuta Sales Alviano ...

  19. Bark chemical analysis explains selective bark damage by rodents

    Czech Academy of Sciences Publication Activity Database

    Heroldová, Marta; Jánová, Eva; Suchomel, J.; Purchart, L.; Homolka, Miloslav

    2009-01-01

    Roč. 2, č. 2 (2009), s. 137-140 ISSN 1803-2451 R&D Projects: GA MZe QH72075 Institutional research plan: CEZ:AV0Z60930519 Keywords : bark damage * bark selection * bark chemical analysis * rowan * beech * spruce * mountain forest regeneration Subject RIV: GK - Forestry

  20. Directed Activities Related to Text: Text Analysis and Text Reconstruction.

    Science.gov (United States)

    Davies, Florence; Greene, Terry

    This paper describes Directed Activities Related to Text (DART), procedures that were developed and are used in the Reading for Learning Project at the University of Nottingham (England) to enhance learning from texts and that fall into two broad categories: (1) text analysis procedures, which require students to engage in some form of analysis of…

  1. Spectrochemical analysis of plutonium using direct current plasma emission spectrometry

    International Nuclear Information System (INIS)

    Morris, W.F.; Fadeff, S.K.; Torres, S.

    1983-01-01

    One year ago, LLNL was just completing the installation of a Direct Current Plasma (DCP) spectrometer for the analysis of Pu and Pu alloys. The installation was completed in December 1982 and has been utilized regularly for Pu analysis since then. This paper discusses the experience with the instrument and some data demonstrating its performance

  2. Chemical and Isotopic Tracers of Groundwater Sustainability: an Overview of New Science Directions

    Science.gov (United States)

    Bullen, T.

    2002-12-01

    Groundwater sustainability is an emerging concept that is rapidly gaining attention from both scientists and water resource managers, particularly with regard to contamination and degradation of water quality in strategic aquifers. The sustainability of a groundwater resource is a complex function of its susceptibility to factors such as intrusion of poor-quality water from diverse sources, lack of sufficient recharge and reorganization of groundwater flowpaths in response to excessive abstraction. In theory the critical limit occurs when degradation becomes irreversible, such that remediative efforts may be fruitless on a reasonable human time scale. Chemical and isotopic tracers are proving to be especially useful tools for assessment of groundwater sustainability issues such as characterization of recharge, identification of potential sources, pathways and impacts of contaminants and prediction of how hydrology will change in response to excessive abstraction. A variety of relatively cost-efficient tracers are now available with which to assess the susceptibility of groundwater reserves to contamination from both natural and anthropogenic sources, and may provide valuable monitoring and regulatory tools for water resource managers. In this overview, the results of several ongoing groundwater studies by the U.S. Geological Survey will be discussed from the perspective of implications for new science directions for groundwater sustainability research that can benefit water policy development. A fundamental concept is that chemical and isotopic tracers used individually often provide ambiguous information, and are most effective when used in a rigorous "multi-tracer" context that considers the complex linkages between the hydrology, geology and biology of groundwater systems.

  3. Analysis of selected chemical parameters in Piemontese wines.

    Science.gov (United States)

    Stępień, Agnieszka E; Stawarczyk, Kinga; Bilek, Maciej; Kędziora, Katarzyna M

    2015-01-01

    Piemontese wines are well known and valued all over the world. The most popular of them are Barolo and Barbaresco wines. However, in Poland, they are still little known and only now are being gradually introduced to a wider range of consumers. The aim of this study was to evaluate the content of inorganic anions, minerals, sugars and glycerol of Piemontese wines from micro-region Langhe, classified as DOCG ("Denominazione di Origine Controllata e Garantita", ie. controlled designation of origin guaranteed) and DOC ("Denominazione di Origine Controllata", ie. controlled designation of origin) products. Seven types of red wines and one type of white wine were tested. High Performance Ion Chromatography with conductometric detection (HPLC-CD) was used to measure the content of inorganic anions, ie. fluorides, chlorides, sulfates and phosphates. Flame atomic absorption spectrometry (F-AAS) was used to measure the content of minerals, ie. magnesium, calcium, sodium, copper, potassium, zinc and iron, while High Performance Liquid Chromatography with charged aerosol detection (HPLC-CAD) was used to measure the content of glycerol and sugars, ie. fructose, glucose and sucrose. Our studies show that although Piemontese wines are characterized by a relatively low content of minerals in comparison with the wines from other regions, they contain a lot of ingredients that have beneficial effects for human health. Moreover, we observed that the studied wines contain particularly high concentration of inorganic ions--phosphates and fluorides. Furthermore, all tested red wines show far reaching similarities in their chemical properties, which is possibly a direct consequence of using in their production locally cultivated grape varieties. Analysis of the wines from the Piemont region, classified as DOCG, DOC, confirmed that these are dry wines of a high quality.

  4. Microfluidic photoinduced chemical oxidation for Ru(bpy)33 + chemiluminescence - A comprehensive experimental comparison with on-chip direct chemical oxidation

    Science.gov (United States)

    Kadavilpparampu, Afsal Mohammed; Al Lawati, Haider A. J.; Suliman, Fakhr Eldin O.

    2017-08-01

    For the first time, the analytical figures of merit in detection capabilities of the very less explored photoinduced chemical oxidation method for Ru(bpy)32 + CL has been investigated in detail using 32 structurally different analytes. It was carried out on-chip using peroxydisulphate and visible light and compared with well-known direct chemical oxidation approaches using Ce(IV). The analytes belong to various chemical classes such as tertiary amine, secondary amine, sulphonamide, betalactam, thiol and benzothiadiazine. Influence of detection environment on CL emission with respect to method of oxidation was evaluated by changing the buffers and pH. The photoinduced chemical oxidation exhibited more universal nature for Ru(bpy)32 + CL in detection towards selected analytes. No additional enhancers, reagents, or modification in instrumental configuration were required. Wide detectability and enhanced emission has been observed for analytes from all the chemical classes when photoinduced chemical oxidation was employed. Some of these analytes are reported for the first time under photoinduced chemical oxidation like compounds from sulphonamide, betalactam, thiol and benzothiadiazine class. On the other hand, many of the selected analytes including tertiary and secondary amines such as cetirizine, azithromycin fexofenadine and proline did not produced any analytically useful CL signal (S/N = 3 or above for 1 μgmL- 1 analyte) under chemical oxidation. The most fascinating observations was in the detection limits; for example ofloxacin was 15 times more intense with a detection limit of 5.81 × 10- 10 M compared to most lowest ever reported 6 × 10- 9 M. Earlier, penicillamine was detected at 0.1 μg mL- 1 after derivatization using photoinduced chemical oxidation, but in this study, we improved it to 5.82 ng mL- 1 without any prior derivatization. The detection limits of many other analytes were also found to be improved by several orders of magnitude under

  5. Direct Analysis of Large Living Organism by Megavolt Electrostatic Ionization Mass Spectrometry

    Science.gov (United States)

    Ng, Kwan-Ming; Tang, Ho-Wai; Man, Sin-Heng; Mak, Pui-Yuk; Choi, Yi-Ching; Wong, Melody Yee-Man

    2014-09-01

    A new ambient ionization method allowing the direct chemical analysis of living human body by mass spectrometry (MS) was developed. This MS method, namely Megavolt Electrostatic Ionization Mass Spectrometry, is based on electrostatic charging of a living individual to megavolt (MV) potential, illicit drugs, and explosives on skin/glove, flammable solvent on cloth/tissue paper, and volatile food substances in breath were readily ionized and detected by a mass spectrometer.

  6. Neutron activation analysis of high-purity iron in comparison with chemical analysis

    International Nuclear Information System (INIS)

    Kinomura, Atsushi; Horino, Yuji; Takaki, Seiichi; Abiko, Kenji

    2000-01-01

    Neutron activation analysis of iron samples of three different purity levels has been performed and compared with chemical analysis for 30 metallic and metalloid impurity elements. The concentration of As, Cl, Cu, Sb and V detected by neutron activation analysis was mostly in agreement with that obtained by chemical analysis. The sensitivity limits of neutron activation analysis of three kinds of iron samples were calculated and found to be reasonable compared with measured values or detection limits of chemical analysis; however, most of them were above the detection limits of chemical analysis. Graphite-shielded irradiation to suppress fast neutron reactions was effective for Mn analysis without decreasing sensitivity to the other impurity elements. (author)

  7. Activation and chemical analysis of drinking water from shallow aquifers

    International Nuclear Information System (INIS)

    Sharma, H.K.; Mittal, V.K.; Sahota, H.S.

    1991-01-01

    In most of the Indian cities drinking water is drawn from shallow aqiufers with the help of hand pumps. These shallow aquifers get easilyl polluted. In the present work we have measured 20 trace elements using Neutron Activation Analysis (NAA) and 8 chemical parameters using standard chemical methods of drinking water drawn from Rajpura city. It was found that almost all water samples are highly polluted. We attribute this to unplaned disposal of industrial and domestic waste over a period of many decades. (author) 11 refs.; 1 fig.; 1 tab

  8. Activation analysis. A basis for chemical similarity and classification

    Energy Technology Data Exchange (ETDEWEB)

    Beeck, J OP de [Ghent Rijksuniversiteit (Belgium). Instituut voor Kernwetenschappen

    1977-01-01

    It is shown that activation analysis is especially suited to serve as a basis for determining the chemical similarity between samples defined by their trace-element concentration patterns. The general problem of classification and identification is discussed. The nature of possible classification structures and their appropriate clustering strategies is considered. A practical computer method is suggested and its application as well as the graphical representation of classification results are given. The possibility for classification using information theory is mentioned. Classification of chemical elements is discussed and practically realized after Hadamard transformation of the concentration variation patterns in a series of samples.

  9. Chemical analysis of plasma-assisted antimicrobial treatment on cotton

    International Nuclear Information System (INIS)

    Kan, C W; Lam, Y L; Yuen, C W M; Luximon, A; Lau, K W; Chen, K S

    2013-01-01

    This paper explores the use of plasma treatment as a pretreatment process to assist the application of antimicrobial process on cotton fabric with good functional effect. In this paper, antimicrobial finishing agent, Microfresh Liquid Formulation 9200-200 (MF), and a binder (polyurethane dispersion, Microban Liquid Formulation R10800-0, MB) will be used for treating the cotton fabric for improving the antimicrobial property and pre-treatment of cotton fabric by plasma under atmospheric pressure will be employed to improve loading of chemical agents. The chemical analysis of the treated cotton fabric will be conducted by Fourier transform Infrared Spectroscopy.

  10. Metal-assisted chemical etching of CIGS thin films for grain size analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Chaowei [Research and Development Centre, Hanergy Thin Film Power Group Limited, Chengdu (China); Loi, Huu-Ha; Duong, Anh; Parker, Magdalena [Failure Analysis Department, MiaSole Hi-Tech Corp., Santa Clara, CA (United States)

    2016-09-15

    Grain size of the CIGS absorber is an important monitoring factor in the CIGS solar cell manufacturing. Electron backscatter diffraction (EBSD) analysis is commonly used to perform CIGS grain size analysis in the scanning electron microscope (SEM). Although direct quantification on SEM image using the average grain intercept (AGI) method is faster and simpler than EBSD, it is hardly applicable on CIGS thin films. The challenge is that, not like polycrystalline silicon, to define grain boundaries by selective chemical etching is not easily realizable for the multi-component CIGS alloy. In this Letter, we present direct quantification of CIGS thin film grain size using the AGI method by developing metal-assisted wet chemical etching process to define CIGS grain boundaries. The calculated value is similar to EBSD result. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Positron annihilation spectroscopy for chemical analysis (PASCA). Chapter 9

    International Nuclear Information System (INIS)

    Cheng, K.L.; Jean, Y.C.

    1988-01-01

    This chapter gives an up to date overview of positron annihilation spectroscopy for chemical analysis (PASCA). As an in situ technique PASCA is especially suitable for studying processes occurring at surfaces. The in situ characteristics of PASCA are treated. The principes of positron annihilation life time spectroscopy (PAL) are discussed and some important analytical applications such as, in determining of total surface areas and cavity volumes in chemical reactions, in the study of chemisorption and catalytic reactions on porous surfaces, in the analysis of bulk materials, in determining molecular association constants in biological systems, in proton and neutron activation analysis, in thin layer chromatography and in tracer technology. 28 refs.; 15 figs.; 8 tabs

  12. Recent Development in Optical Chemical Sensors Coupling with Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Fuensanta Sánchez Rojas

    2006-10-01

    Full Text Available Optical techniques for chemical analysis are well established and sensors based on thesetechniques are now attracting considerable attention because of their importance in applications suchas environmental monitoring, biomedical sensing, and industrial process control. On the other hand,flow injection analysis (FIA is advisable for the rapid analysis of microliter volume samples and canbe interfaced directly to the chemical process. The FIA has become a widespread automatic analyticalmethod for more reasons; mainly due to the simplicity and low cost of the setups, their versatility, andease of assembling. In this paper, an overview of flow injection determinations by using opticalchemical sensors is provided, and instrumentation, sensor design, and applications are discussed. Thiswork summarizes the most relevant manuscripts from 1980 to date referred to analysis using opticalchemical sensors in FIA.

  13. An Inverse Analysis Approach to the Characterization of Chemical Transport in Paints

    Science.gov (United States)

    Willis, Matthew P.; Stevenson, Shawn M.; Pearl, Thomas P.; Mantooth, Brent A.

    2014-01-01

    The ability to directly characterize chemical transport and interactions that occur within a material (i.e., subsurface dynamics) is a vital component in understanding contaminant mass transport and the ability to decontaminate materials. If a material is contaminated, over time, the transport of highly toxic chemicals (such as chemical warfare agent species) out of the material can result in vapor exposure or transfer to the skin, which can result in percutaneous exposure to personnel who interact with the material. Due to the high toxicity of chemical warfare agents, the release of trace chemical quantities is of significant concern. Mapping subsurface concentration distribution and transport characteristics of absorbed agents enables exposure hazards to be assessed in untested conditions. Furthermore, these tools can be used to characterize subsurface reaction dynamics to ultimately design improved decontaminants or decontamination procedures. To achieve this goal, an inverse analysis mass transport modeling approach was developed that utilizes time-resolved mass spectroscopy measurements of vapor emission from contaminated paint coatings as the input parameter for calculation of subsurface concentration profiles. Details are provided on sample preparation, including contaminant and material handling, the application of mass spectrometry for the measurement of emitted contaminant vapor, and the implementation of inverse analysis using a physics-based diffusion model to determine transport properties of live chemical warfare agents including distilled mustard (HD) and the nerve agent VX. PMID:25226346

  14. Quality system of the Chemical Analysis Laboratory to fulfill the requirements with Certification Organizations

    International Nuclear Information System (INIS)

    Merlo S, L.; Rodriguez L, R.; Cota S, G.

    1996-01-01

    In the present work was described the Quality System established in the Chemical Analysis Department to fulfill with the Organization requirements, personnel, measurement equipment, calibration, working procedures, etc. to get official acknowledgment by the National Assurance System for Testing laboratories, dependent of the General Standards Direction. There are described the available resources, the performance and control of each of one principal points of the system. (Author)

  15. Curriculum Assessment as a Direct Tool in ABET Outcomes Assessment in a Chemical Engineering Programme

    Science.gov (United States)

    Abu-Jdayil, Basim; Al-Attar, Hazim

    2010-01-01

    The chemical engineering programme at the United Arab Emirates University is designed to fulfil the Accreditation Board for Engineering and Technology (ABET) (A-K) EC2000 criteria. The Department of Chemical & Petroleum Engineering has established a well-defined process for outcomes assessment for the chemical engineering programme in order to…

  16. Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

    CERN Document Server

    Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

    2002-01-01

    The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

  17. Direct chemical synthesis of MnO2 nanowhiskers on MXene surfaces for supercapacitor applications

    KAUST Repository

    Baby, Rakhi Raghavan

    2016-07-05

    Transition metal carbides (MXenes) are an emerging class of two dimensional (2D) materials with promising electrochemical energy storage performance. Herein, for the first time, by direct chemical synthesis, nanocrystalline ε-MnO2 whiskers were formed on MXene nanosheet surfaces (ε-MnO2/Ti2CTx and ε-MnO2/Ti3C2Tx) to make nanocomposite electrodes for aqueous pseudocapacitors. The ε-MnO2 nanowhiskers increase the surface area of the composite electrode and enhance the specific capacitance by nearly three orders of magnitude compared to pure MXene based symmetric supercapacitors. Combined with enhanced pseudocapacitance, the fabricated ε-MnO2/MXene supercapacitors exhibited excellent cycling stability with ~88% of the initial specific capacitance retained after 10000 cycles which is much higher than pure ε-MnO2 based supercapacitors (~74%). The proposed electrode structure capitalizes on the high specific capacitance of MnO2 and the ability of MXenes to improve conductivity and cycling stability.

  18. Implementation of the NMR CHEmical Shift Covariance Analysis (CHESCA): A Chemical Biologist's Approach to Allostery.

    Science.gov (United States)

    Boulton, Stephen; Selvaratnam, Rajeevan; Ahmed, Rashik; Melacini, Giuseppe

    2018-01-01

    Mapping allosteric sites is emerging as one of the central challenges in physiology, pathology, and pharmacology. Nuclear Magnetic Resonance (NMR) spectroscopy is ideally suited to map allosteric sites, given its ability to sense at atomic resolution the dynamics underlying allostery. Here, we focus specifically on the NMR CHEmical Shift Covariance Analysis (CHESCA), in which allosteric systems are interrogated through a targeted library of perturbations (e.g., mutations and/or analogs of the allosteric effector ligand). The atomic resolution readout for the response to such perturbation library is provided by NMR chemical shifts. These are then subject to statistical correlation and covariance analyses resulting in clusters of allosterically coupled residues that exhibit concerted responses to the common set of perturbations. This chapter provides a description of how each step in the CHESCA is implemented, starting from the selection of the perturbation library and ending with an overview of different clustering options.

  19. All-Russia conference on chemical analysis of substances and materials. Abstracts of reports

    International Nuclear Information System (INIS)

    2000-01-01

    Collection contains abstracts of reports on chemical analysis of foods, drugs, environmental materials. Methods of chemical analysis used in such regions as chemical control in agriculture, criminology, art and archaeology, biotechnology, geology, chemistry and petrochemistry, metallurgy, metrology are presented. Theoretical, methodological and applied aspects of chemical analysis are considered [ru

  20. The collection and field chemical analysis of water samples

    International Nuclear Information System (INIS)

    Korte, N.E.; Ealey, D.T.; Hollenbach, M.H.

    1984-01-01

    A successful water sampling program requires a clear understanding of appropriate measurement and sampling procedures in order to obtain reliable field data and representative samples. It is imperative that the personnel involved have a thorough knowledge of the limitations of the techniques being used. Though this seems self-evident, many sampling and field-chemical-analysis programs are still not properly conducted. Recognizing these problems, the Department of Energy contracted with Bendix Field Engineering Corporation through the Technical Measurements Center to develop and select procedures for water sampling and field chemical analysis at waste sites. The fundamental causese of poor field programs are addressed in this paper, largely through discussion of specific field-measurement techniques and their limitations. Recommendations for improvement, including quality-assurance measures, are also presented

  1. Regression analysis of a chemical reaction fouling model

    International Nuclear Information System (INIS)

    Vasak, F.; Epstein, N.

    1996-01-01

    A previously reported mathematical model for the initial chemical reaction fouling of a heated tube is critically examined in the light of the experimental data for which it was developed. A regression analysis of the model with respect to that data shows that the reference point upon which the two adjustable parameters of the model were originally based was well chosen, albeit fortuitously. (author). 3 refs., 2 tabs., 2 figs

  2. Gas analysis during the chemical vapor deposition of carbon

    International Nuclear Information System (INIS)

    Lieberman, M.L.; Noles, G.T.

    1973-01-01

    Gas chromatographic analyses were performed during the chemical vapor deposition of carbon in both isothermal and thermal gradient systems. Such data offer insight into the gas phase processes which occur during deposition and the interrelations which exist between gas composition, deposition rate, and resultant structure of the deposit. The results support a carbon CVD model presented previously. The application of chromatographic analysis to research, development, and full-scale facilities is shown. (U.S.)

  3. Fisher statistics for analysis of diffusion tensor directional information.

    Science.gov (United States)

    Hutchinson, Elizabeth B; Rutecki, Paul A; Alexander, Andrew L; Sutula, Thomas P

    2012-04-30

    A statistical approach is presented for the quantitative analysis of diffusion tensor imaging (DTI) directional information using Fisher statistics, which were originally developed for the analysis of vectors in the field of paleomagnetism. In this framework, descriptive and inferential statistics have been formulated based on the Fisher probability density function, a spherical analogue of the normal distribution. The Fisher approach was evaluated for investigation of rat brain DTI maps to characterize tissue orientation in the corpus callosum, fornix, and hilus of the dorsal hippocampal dentate gyrus, and to compare directional properties in these regions following status epilepticus (SE) or traumatic brain injury (TBI) with values in healthy brains. Direction vectors were determined for each region of interest (ROI) for each brain sample and Fisher statistics were applied to calculate the mean direction vector and variance parameters in the corpus callosum, fornix, and dentate gyrus of normal rats and rats that experienced TBI or SE. Hypothesis testing was performed by calculation of Watson's F-statistic and associated p-value giving the likelihood that grouped observations were from the same directional distribution. In the fornix and midline corpus callosum, no directional differences were detected between groups, however in the hilus, significant (pstatistical comparison of tissue structural orientation. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. The Signal and Noise Analysis of Direct Conversion EHM Transceivers

    Directory of Open Access Journals (Sweden)

    Shayegh

    2006-01-01

    Full Text Available A direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. The circuits consist of even harmonic mixers (EHMs realized with antiparallel diode pairs (APDPs. We evaluate the different levels of I/Q imbalances and DC offsets and use signal space concepts to analyze the bit error rate (BER of the proposed transceiver using M-ary QAM schemes. Moreover, the simultaneous analysis of the signal and noise has been presented.

  5. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de Souza; Py Junior, Delcy de Azevedo; Goncalves, Simone, E-mail: wspereira@inb.gov.br [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Grupo Multidisciplinar de Radioprotecao; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Biologia. Lab. de Radiobiologia e Radiometria Pedro Lopes dos Santos; Morais, Gustavo Ferrari de; Campelo, Emanuele Lazzaretti Cordova [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Coordenacao de Desenvolvimento de Processos; Dores, Luis Augusto de Carvalho Bresser [Unidade de Tratamento de Minerio (UTM/INB), Pocos de Caldas, MG (Brazil). Gerencia de Descomissionamento

    2011-07-01

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  6. Cluster analysis to evaluate stable chemical elements and physical-chemical parameters behavior on uranium mining waste

    International Nuclear Information System (INIS)

    Pereira, Wagner de Souza; Py Junior, Delcy de Azevedo; Goncalves, Simone; Kelecom, Alphonse; Morais, Gustavo Ferrari de; Campelo, Emanuele Lazzaretti Cordova; Dores, Luis Augusto de Carvalho Bresser

    2011-01-01

    The Ore Treating Unit (UTM, in portuguese) is a deactivated uranium mine. A cluster analysis was used to evaluate the behavior of stable chemical elements and physical-chemical parameters in their effluents. The utilization of the cluster analysis proved itself effective in the assessment, allowing the identification of groups of chemical elements, physical-chemical parameters and their joint analysis (elements and parameters). As a result we may assert, based on data analysis, that there is a strong link between calcium and magnesium and between aluminum and rare-earth oxides on UTM's effluents. Sulphate was also identified as strongly linked to total and dissolved solids, and those to electrical conductivity. There were other associations, but not so strongly linked. Further gathering, to seasonal evaluation, are required in order to confirm those analysis. Additional statistical analysis (factor analysis) must be used to try to identify the origin of the identified groups on this analysis. (author)

  7. Full scale experimental analysis of wind direction changes (EOD)

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose

    2007-01-01

    wind direction gust amplitudes associated with the investigated European sites are low compared to the recommended IEC- values. However, these values, as function of the mean wind speed, are difficult to validate thoroughly due to the limited number of fully correlated measurements....... the magnitudes of a joint gust event defined by a simultaneously wind speed- and direction change in order to obtain an indication of the validity of the magnitudes specified in the IEC code. The analysis relates to pre-specified recurrence periods and is based on full-scale wind field measurements. The wind......A coherent wind speed and wind direction change (ECD) load case is defined in the wind turbine standard. This load case is an essential extreme load case that e.g. may be design driving for flap defection of active stall controlled wind turbines. The present analysis identifies statistically...

  8. Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling

    Directory of Open Access Journals (Sweden)

    T. S. Bates

    2006-01-01

    Full Text Available The largest uncertainty in the radiative forcing of climate change over the industrial era is that due to aerosols, a substantial fraction of which is the uncertainty associated with scattering and absorption of shortwave (solar radiation by anthropogenic aerosols in cloud-free conditions (IPCC, 2001. Quantifying and reducing the uncertainty in aerosol influences on climate is critical to understanding climate change over the industrial period and to improving predictions of future climate change for assumed emission scenarios. Measurements of aerosol properties during major field campaigns in several regions of the globe during the past decade are contributing to an enhanced understanding of atmospheric aerosols and their effects on light scattering and climate. The present study, which focuses on three regions downwind of major urban/population centers (North Indian Ocean (NIO during INDOEX, the Northwest Pacific Ocean (NWP during ACE-Asia, and the Northwest Atlantic Ocean (NWA during ICARTT, incorporates understanding gained from field observations of aerosol distributions and properties into calculations of perturbations in radiative fluxes due to these aerosols. This study evaluates the current state of observations and of two chemical transport models (STEM and MOZART. Measurements of burdens, extinction optical depth (AOD, and direct radiative effect of aerosols (DRE – change in radiative flux due to total aerosols are used as measurement-model check points to assess uncertainties. In-situ measured and remotely sensed aerosol properties for each region (mixing state, mass scattering efficiency, single scattering albedo, and angular scattering properties and their dependences on relative humidity are used as input parameters to two radiative transfer models (GFDL and University of Michigan to constrain estimates of aerosol radiative effects, with uncertainties in each step propagated through the analysis. Constraining the radiative

  9. Trend-Analysis and Research Direction in Construction Management Literature

    DEFF Research Database (Denmark)

    Larsen, Jesper Kranker; Ussing, Lene Faber; Brunø, Thomas Ditlev

    2013-01-01

    Planning and scheduling, both in the form of pre-assembly construction as well as increase in cost and time are all themes that haven’t been studies in a trend-analysis, with the purpose of finding gaps and research directions in the literature. The aim of this paper is therefor to analyze...... of Construction Engineering and Management....

  10. Direct identification of pure penicillium species using image analysis

    DEFF Research Database (Denmark)

    Dørge, Thorsten Carlheim; Carstensen, Jens Michael; Frisvad, Jens Christian

    2000-01-01

    This paper presents a method for direct identification of fungal species solely by means of digital image analysis of colonies as seen after growth on a standard medium. The method described is completely automated and hence objective once digital images of the reference fungi have been establish...

  11. Directed evolution strategies for enantiocomplementary haloalkane dehalogenases: from chemical waste to enantiopure building blocks.

    Science.gov (United States)

    van Leeuwen, Jan G E; Wijma, Hein J; Floor, Robert J; van der Laan, Jan-Metske; Janssen, Dick B

    2012-01-02

    We used directed evolution to obtain enantiocomplementary haloalkane dehalogenase variants that convert the toxic waste compound 1,2,3-trichloropropane (TCP) into highly enantioenriched (R)- or (S)-2,3-dichloropropan-1-ol, which can easily be converted into optically active epichlorohydrins-attractive intermediates for the synthesis of enantiopure fine chemicals. A dehalogenase with improved catalytic activity but very low enantioselectivity was used as the starting point. A strategy that made optimal use of the limited capacity of the screening assay, which was based on chiral gas chromatography, was developed. We used pair-wise site-saturation mutagenesis (SSM) of all 16 noncatalytic active-site residues during the initial two rounds of evolution. The resulting best R- and S-enantioselective variants were further improved in two rounds of site-restricted mutagenesis (SRM), with incorporation of carefully selected sets of amino acids at a larger number of positions, including sites that are more distant from the active site. Finally, the most promising mutations and positions were promoted to a combinatorial library by using a multi-site mutagenesis protocol with restricted codon sets. To guide the design of partly undefined (ambiguous) codon sets for these restricted libraries we employed structural information, the results of multiple sequence alignments, and knowledge from earlier rounds. After five rounds of evolution with screening of only 5500 clones, we obtained two strongly diverged haloalkane dehalogenase variants that give access to (R)-epichlorohydrin with 90 % ee and to (S)-epichlorohydrin with 97 % ee, containing 13 and 17 mutations, respectively, around their active sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Peroxone mineralization of chemical oxygen demand for direct potable water reuse: Kinetics and process control.

    Science.gov (United States)

    Wu, Tingting; Englehardt, James D

    2015-04-15

    Mineralization of organics in secondary effluent by the peroxone process was studied at a direct potable water reuse research treatment system serving an occupied four-bedroom, four bath university residence hall apartment. Organic concentrations were measured as chemical oxygen demand (COD) and kinetic runs were monitored at varying O3/H2O2 dosages and ratios. COD degradation could be accurately described as the parallel pseudo-1st order decay of rapidly and slowly-oxidizable fractions, and effluent COD was reduced to below the detection limit (<0.7 mg/L). At dosages ≥4.6 mg L(-1) h(-1), an O3/H2O2 mass ratio of 3.4-3.8, and initial COD <20 mg/L, a simple first order decay was indicated for both single-passed treated wastewater and recycled mineral water, and a relationship is proposed and demonstrated to estimate the pseudo-first order rate constant for design purposes. At this O3/H2O2 mass ratio, ORP and dissolved ozone were found to be useful process control indicators for monitoring COD mineralization in secondary effluent. Moreover, an average second order rate constant for OH oxidation of secondary effluent organics (measured as MCOD) was found to be 1.24 × 10(7) ± 0.64 × 10(7) M(-1) S(-1). The electric energy demand of the peroxone process is estimated at 1.73-2.49 kW h electric energy for removal of one log COD in 1 m(3) secondary effluent, comparable to the energy required for desalination of medium strength seawater. Advantages/disadvantages of the two processes for municipal wastewater reuse are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Nanoparticle-based optical biosensors for the direct detection of organophosphate chemical warfare agents and pesticides

    International Nuclear Information System (INIS)

    Simonian, A.L.; Good, T.A.; Wang, S.-S.; Wild, J.R.

    2005-01-01

    Neurotoxic organophosphates (OP) have found widespread use in the environment for insect control. In addition, there is the increasing threat of use of OP based chemical warfare agents in both ground based warfare and terrorist attacks. Together, these trends necessitate the development of simple and specific methods for discriminative detection of ultra low quantities of OP neurotoxins. In our previous investigations a new biosensor for the direct detection of organophosphorus neurotoxins was pioneered. In this system, the enzymatic hydrolysis of OP neurotoxins by organophosphate hydrolase (OPH) generated two protons in each hydrolytic turnover through reactions in which P-X bonds are cleaved. The sensitivity of this biosensor was limited due to the potentiometric method of detection. Recently, it was reported that a change in fluorescence properties of a fluorophore in the vicinity of gold nanoparticles might be used for detection of nanomolar concentrations of DNA oligonucleotides. The detection strategy was based on the fact that an enhancement or quenching of fluorescence intensity is a function of the distances between the gold nanoparticle and fluorophore. While these reports have demonstrated the use of nanoparticle-based sensors for the detection of target DNA, we observed that the specificity of enzyme-substrate interactions could be exploited in similar systems. To test the feasibility of this approach, OPH-gold nanoparticle conjugates were prepared, then incubated with a fluorescent enzyme inhibitor or decoy. The fluorescence intensity of the decoy was sensitive to the proximity of the gold nanoparticle, and thus could be used to indicate that the decoy was bound to the OPH. Then different paraoxon concentrations were introduced to the OPH-nanoparticle-conjugate-decoy mixtures, and normalized ratio of fluorescence intensities were measured. The greatest sensitivity to paraoxon was obtained when decoys and OPH-gold nanoparticle conjugates were present at

  14. The direct measurement of the heteronuclear chemical shifts relative to tetramethylsilane

    International Nuclear Information System (INIS)

    Moritz, A.G.

    1988-12-01

    The measurement of heteronuclear chemical shifts using absolute frequencies of the heteronucleus and the 1 H resonance of tetramethylsilane has been examined. This method avoids the problems associated with external standards and gives results which can be obtained quickly and with high precision. The method has a number of advantages in the accurate measurement of chemical shifts, as for example 31 P in chemical warfare agents and related chemicals and allows multinuclear data to be obtained without dynamic range or potential interference problems. 15 refs., 4 tabs

  15. Chemical Abundance Analysis of Moving Group W11450 (Latham 1)

    Science.gov (United States)

    O'Connell, Julia E.; Martens, Kylee; Frinchaboy, Peter M.

    2016-12-01

    We present elemental abundances for all seven stars in Moving Group W11450 (Latham 1) to determine if they may be chemically related. These stars appear to be both spatially and kinematically related, but no spectroscopic abundance analysis exists in literature. Abundances for eight elements were derived via equivalent width analyses of high-resolution (R ˜ 60,000), high-signal-to-noise ratio ( ˜ 100) spectra obtained with the Otto Struve 2.1 m telescope and the Sandiford Echelle Spectrograph at McDonald Observatory. The large star-to-star scatter in metallicity, -0.55 ≤ [Fe/H] ≤slant 0.06 dex (σ = 0.25), implies these stars were not produced from the same chemically homogeneous molecular cloud, and are therefore not part of a remnant or open cluster as previously proposed. Prior to this analysis, it was suggested that two stars in the group, W11449 and W11450, are possible wide binaries. The candidate wide binary pair show similar chemical abundance patterns with not only iron but with other elements analyzed in this study, suggesting the proposed connection between these two stars may be real.

  16. Microfluidic photoinduced chemical oxidation for Ru(bpy)33+ chemiluminescence - A comprehensive experimental comparison with on-chip direct chemical oxidation.

    Science.gov (United States)

    Kadavilpparampu, Afsal Mohammed; Al Lawati, Haider A J; Suliman, Fakhr Eldin O

    2017-08-05

    For the first time, the analytical figures of merit in detection capabilities of the very less explored photoinduced chemical oxidation method for Ru(bpy) 3 2+ CL has been investigated in detail using 32 structurally different analytes. It was carried out on-chip using peroxydisulphate and visible light and compared with well-known direct chemical oxidation approaches using Ce(IV). The analytes belong to various chemical classes such as tertiary amine, secondary amine, sulphonamide, betalactam, thiol and benzothiadiazine. Influence of detection environment on CL emission with respect to method of oxidation was evaluated by changing the buffers and pH. The photoinduced chemical oxidation exhibited more universal nature for Ru(bpy) 3 2+ CL in detection towards selected analytes. No additional enhancers, reagents, or modification in instrumental configuration were required. Wide detectability and enhanced emission has been observed for analytes from all the chemical classes when photoinduced chemical oxidation was employed. Some of these analytes are reported for the first time under photoinduced chemical oxidation like compounds from sulphonamide, betalactam, thiol and benzothiadiazine class. On the other hand, many of the selected analytes including tertiary and secondary amines such as cetirizine, azithromycin fexofenadine and proline did not produced any analytically useful CL signal (S/N=3 or above for 1μgmL -1 analyte) under chemical oxidation. The most fascinating observations was in the detection limits; for example ofloxacin was 15 times more intense with a detection limit of 5.81×10 -10 M compared to most lowest ever reported 6×10 -9 M. Earlier, penicillamine was detected at 0.1μgmL -1 after derivatization using photoinduced chemical oxidation, but in this study, we improved it to 5.82ngmL -1 without any prior derivatization. The detection limits of many other analytes were also found to be improved by several orders of magnitude under photoinduced

  17. QSAR modeling and chemical space analysis of antimalarial compounds

    Science.gov (United States)

    Sidorov, Pavel; Viira, Birgit; Davioud-Charvet, Elisabeth; Maran, Uko; Marcou, Gilles; Horvath, Dragos; Varnek, Alexandre

    2017-05-01

    Generative topographic mapping (GTM) has been used to visualize and analyze the chemical space of antimalarial compounds as well as to build predictive models linking structure of molecules with their antimalarial activity. For this, a database, including 3000 molecules tested in one or several of 17 anti- Plasmodium activity assessment protocols, has been compiled by assembling experimental data from in-house and ChEMBL databases. GTM classification models built on subsets corresponding to individual bioassays perform similarly to the earlier reported SVM models. Zones preferentially populated by active and inactive molecules, respectively, clearly emerge in the class landscapes supported by the GTM model. Their analysis resulted in identification of privileged structural motifs of potential antimalarial compounds. Projection of marketed antimalarial drugs on this map allowed us to delineate several areas in the chemical space corresponding to different mechanisms of antimalarial activity. This helped us to make a suggestion about the mode of action of the molecules populating these zones.

  18. Method for fractional solid-waste sampling and chemical analysis

    DEFF Research Database (Denmark)

    Riber, Christian; Rodushkin, I.; Spliid, Henrik

    2007-01-01

    four subsampling methods and five digestion methods, paying attention to the heterogeneity and the material characteristics of the waste fractions, it was possible to determine 61 substances with low detection limits, reasonable variance, and high accuracy. For most of the substances of environmental...... of variance (20-85% of the overall variation). Only by increasing the sample size significantly can this variance be reduced. The accuracy and short-term reproducibility of the chemical characterization were good, as determined by the analysis of several relevant certified reference materials. Typically, six...... to eight different certified reference materials representing a range of concentrations levels and matrix characteristics were included. Based on the documentation provided, the methods introduced were considered satisfactory for characterization of the chemical composition of waste-material fractions...

  19. Coal Direct Chemical Looping Retrofit to Pulverized Coal Power Plants for In-Situ CO2 Capture

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Liang; Li, Fanxing; Kim, Ray; Bayham, Samuel; McGiveron, Omar; Tong, Andrew; Connell, Daniel; Luo, Siwei; Sridhar, Deepak; Wang, Fei; Sun, Zhenchao; Fan, Liang-Shih

    2013-09-30

    A novel Coal Direct Chemical Looping (CDCL) system is proposed to effectively capture CO2 from existing PC power plants. The work during the past three years has led to an oxygen carrier particle with satisfactory performance. Moreover, successful laboratory, bench scale, and integrated demonstrations have been performed. The proposed project further advanced the novel CDCL technology to sub-pilot scale (25 kWth). To be more specific, the following objectives attained in the proposed project are: 1. to further improve the oxygen carrying capacity as well as the sulfur/ash tolerance of the current (working) particle; 2. to demonstrate continuous CDCL operations in an integrated mode with > 99% coal (bituminous, subbituminous, and lignite) conversion as well as the production of high temperature exhaust gas stream that is suitable for steam generation in existing PC boilers; 3. to identify, via demonstrations, the fate of sulfur and NOx; 4. to conduct thorough techno-economic analysis that validates the technical and economical attractiveness of the CDCL system. The objectives outlined above were achieved through collaborative efforts among all the participants. CONSOL Energy Inc. performed the techno-economic analysis of the CDCL process. Shell/CRI was able to perform feasibility and economic studies on the large scale particle synthesis and provide composite particles for the sub-pilot scale testing. The experience of B&W (with boilers) and Air Products (with handling gases) assisted the retrofit system design as well as the demonstration unit operations. The experience gained from the sub-pilot scale demonstration of the Syngas Chemical Looping (SCL) process at OSU was able to ensure the successful handling of the solids. Phase 1 focused on studies to improve the current particle to better suit the CDCL operations. The optimum operating conditions for the reducer reactor such as the temperature, char gasification enhancer type, and flow rate were identified. The

  20. Direct sampling of chemical weapons in water by photoionization mass spectrometry.

    Science.gov (United States)

    Syage, Jack A; Cai, Sheng-Suan; Li, Jianwei; Evans, Matthew D

    2006-05-01

    The vulnerability of water supplies to toxic contamination calls for fast and effective means for screening water samples for multiple threats. We describe the use of photoionization (PI) mass spectrometry (MS) for high-speed, high-throughput screening and molecular identification of chemical weapons (CW) threats and other hazardous compounds. The screening technology can detect a wide range of compounds at subacute concentrations with no sample preparation and a sampling cycle time of approximately 45 s. The technology was tested with CW agents VX, GA, GB, GD, GF, HD, HN1, and HN3, in addition to riot agents and precursors. All are sensitively detected and give simple PI mass spectra dominated by the parent ion. The target application of the PI MS method is as a routine, real-time early warning system for CW agents and other hazardous compounds in air and in water. In this work, we also present comprehensive measurements for water analysis and report on the system detection limits, linearity, quantitation accuracy, and false positive (FP) and false negative rates for concentrations at subacute levels. The latter data are presented in the form of receiver operating characteristic curves of the form of detection probability P(D) versus FP probability P(FP). These measurements were made using the CW surrogate compounds, DMMP, DEMP, DEEP, and DIMP. Method detection limits (3sigma) obtained using a capillary injection method yielded 1, 6, 3, and 2 ng/mL, respectively. These results were obtained using 1-microL injections of water samples without any preparation, corresponding to mass detection limits of 1, 6, 3, and 2 pg, respectively. The linear range was about 3-4 decades and the dynamic range about 4-5 decades. The relative standard deviations were generally <10% at CW subacute concentrations levels.

  1. Rapid characterization of chemical markers for discrimination of Moutan Cortex and its processed products by direct injection-based mass spectrometry profiling and metabolomic method.

    Science.gov (United States)

    Li, Chao-Ran; Li, Meng-Ning; Yang, Hua; Li, Ping; Gao, Wen

    2018-06-01

    Processing of herbal medicines is a characteristic pharmaceutical technique in Traditional Chinese Medicine, which can reduce toxicity and side effect, improve the flavor and efficacy, and even change the pharmacological action entirely. It is significant and crucial to perform a method to find chemical markers for differentiating herbal medicines in different processed degrees. The aim of this study was to perform a rapid and reasonable method to discriminate Moutan Cortex and its processed products, and to reveal the characteristics of chemical components depend on chemical markers. Thirty batches of Moutan Cortex and its processed products, including 11 batches of Raw Moutan Cortex (RMC), 9 batches of Moutan Cortex Tostus (MCT) and 10 batches of Moutan Cortex Carbonisatus (MCC), were directly injected in electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF MS) for rapid analysis in positive and negative mode. Without chromatographic separation, each run was completed within 3 min. The raw MS data were automatically extracted by background deduction and molecular feature (MF) extraction algorithm. In negative mode, a total of 452 MFs were obtained and then pretreated by data filtration and differential analysis. After that, the filtered 85 MFs were treated by principal component analysis (PCA) to reduce the dimensions. Subsequently, a partial least squares discrimination analysis (PLS-DA) model was constructed for differentiation and chemical markers detection of Moutan Cortex in different processed degrees. The positive mode data were treated as same as those in negative mode. RMC, MCT and MCC were successfully classified. Moreover, 14 and 3 chemical markers from negative and positive mode respectively, were screened by the combination of their relative peak areas and the parameter variable importance in the projection (VIP) values in PLS-DA model. The content changes of these chemical markers were employed in order to illustrate

  2. Transcriptomic and genetic analysis of direct interspecies electron transfer

    DEFF Research Database (Denmark)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Summers, Zarath M

    2013-01-01

    The possibility that metatranscriptomic analysis could distinguish between direct interspecies electron transfer (DIET) and H2 interspecies transfer (HIT) in anaerobic communities was investigated by comparing gene transcript abundance in cocultures in which Geobacter sulfurreducens....... These results demonstrate that there are unique gene expression patterns that distinguish DIET from HIT and suggest that metatranscriptomics may be a promising route to investigate interspecies electron transfer pathways in more-complex environments....

  3. Tissue chemical analysis with muonic X-rays

    International Nuclear Information System (INIS)

    Hutson, R.L.; Reidy, J.J.; Springer, K.; Daniel, H.; Knowles, H.B.

    1976-01-01

    The stopped muon channel at the Clinton P. Anderson Meson Physics Facility (LAMPF) was used as a source of muons for studying the elemental composition of tissue with muonic X rays. The X ray spectra from several types of tissue were used to determine the amounts of carbon, nitrogen, and oxygen present. These determinations agree with the results of more conventional chemical analysis. The results show that muonic X rays offer a non-invasive technique for determining the amounts of the more abundant elements present in selected regions of the body. (orig.) [de

  4. Analysis of the chemical equilibrium of combustion at constant volume

    Directory of Open Access Journals (Sweden)

    Marius BREBENEL

    2014-04-01

    Full Text Available Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant volume is next considered as example of application, observing the changes occurring in the composition of the combustion gases depending on temperature.

  5. Chemical phase analysis of seed mediated synthesized anisotropic silver nanoparticles

    International Nuclear Information System (INIS)

    Bharti, Amardeep; Goyal, Navdeep; Singh, Suman; Singla, M. L.

    2015-01-01

    Noble-metal nanoparticles are of great interest because of its broad applications almost in every stream (i.e. biology, chemistry and engineering) due to their unique size/shape dependant properties. In this paper, chemical phase of seed mediated synthesized anisotropic silver nanoparticle (AgNPs) has been investigated via fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These nanaoparticles were synthesized by seed-growth method controlled by urea and dextrose results to highly stable 12-20 nm particle size revealed by zeta potential and transmission electron microscopy (TEM)

  6. Treatment systems for liquid wastes generated in chemical analysis laboratories

    International Nuclear Information System (INIS)

    Linda Berrio; Oscar Beltran; Edison Agudelo; Santiago Cardona

    2012-01-01

    Nowadays, handling of liquid wastes from chemical analysis laboratories is posing problems to different public and private organizations because of its requirements of an integrated management. This article reviews various treatment technologies and its removal efficiencies in order to establish criteria for selecting the system and the appropriate variables to achieve research objectives as well as environmental sustainability. Review begins with a description of the problem and continues with the study of treatments for laboratory wastes. These technologies are segregated into physicochemical and biological treatments that comprise a variety of processes, some of which are considered in this review.

  7. Chemical analysis of dairy cattle feed from Brazil

    International Nuclear Information System (INIS)

    Luis Gustavo Cofani dos Santos; De Nadai Fernandes, E.A.; Marcio Arruda Bacchi; Lucimara Blumer; Gabriel Adrian Sarries; Fernando Barbosa Junior

    2009-01-01

    The bovine dairy cattle demand diets of high nutritional value being essential to know chemical composition of feed supplied to cows to achieve high levels of quality, safety and productivity of milk. Different roughages and concentrates from Minas Gerais and Rio Grande do Sul states, Brazil, were analyzed by instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Concentrate and roughage samples were differentiated by mass fractions of As, Ba, Mg, P, Rb and Sr. Samples of concentrate from both origins were differentiated by mass fractions of As, Cd, Co, Cr, Cs, Ni and Rb. (author)

  8. Integrated polymer waveguides for absorbance detection in chemical analysis systems

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; El-Ali, Jamil; Wolff, Anders

    2003-01-01

    A chemical analysis system for absorbance detection with integrated polymer waveguides is reported for the first time. The fabrication procedure relies on structuring of a single layer of the photoresist SU-8, so both the microfluidic channel network and the optical components, which include planar....... The emphasis of this paper is on the signal-to-noise ratio of the detection and its relation to the sensitivity. Two absorbance cells with an optical path length of 100 μm and 1000 μm were characterized and compared in terms of sensitivity, limit of detection and effective path length for measurements...

  9. Imaging, structural, and chemical analysis of silicon nanowires

    International Nuclear Information System (INIS)

    Barsotti, R.J. Jr.; Fischer, J.E.; Lee, C.H.; Mahmood, J.; Adu, C.K.W.; Eklund, P.C.

    2002-01-01

    Laser ablation has been used to grow silicon nanowires with an average silicon crystal core diameter of 6.7 nm±2.9 nm surrounded by an amorphous SiO x sheath of 1-2 nm, the smallest silicon wires reported in the literature. Imaging, chemical, and structural analysis of these wires are reported. Due to the growth temperature and the presence of calcium impurities and trace oxygen, two distinct types of wires are found. They appear to grow by two different processes. One requires a metal catalyst, the other is catalyzed by oxygen. Suggestions for controlled synthesis based on these growth mechanisms are made

  10. Determination of air pollutants by nuclear chemical analysis

    International Nuclear Information System (INIS)

    Lesny, J.; Toelgyessy, J.

    1975-01-01

    Nuclear analytical methods are discussed with a view to their applicability in the determination of air pollutants. It is shown that some methods (use of radioactive kryptonates in automatic analyzers, application of activation analysis, X-ray fluorescence methods) are developed in theory and proven in practice in such an extent to be widely used in the near future in the control of the environment. Many other methods are becoming increasingly important for the solution of specific problems of environmental protection (such as the control of sudden environmental contamination in the proximity of chemical plants and industrial centers). (author)

  11. Crystal-Chemical Analysis of Soil at Rocknest, Gale Crater

    Science.gov (United States)

    Morrison, S. M.; Downs, R. T.; Blake, D. F.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Yen, A. S.; Chipera, S. J.; Treiman, A. H.; Vaniman, D. T.; hide

    2013-01-01

    The CheMin instrument on the Mars Science Laboratory rover Curiosity performed X-ray diffraction analysis on Martian soil [1] at Rocknest in Gale Crater. In particular, crystalline phases from scoop 5 were identified and analyzed with the Rietveld method [2]. Refined unit-cell parameters are reported in Table 1. Comparing these unit-cell parameters with those in the literature provides an estimate of the chemical composition of the crystalline phases. For instance, Fig. 1 shows the Mg-content of Fa-Fo olivine as a function of the b unit-cell parameter using literature data. Our refined b parameter is indicated by the black triangle.

  12. Physcio chemical analysis of browning inhibitors treated solanum turberosum powder

    International Nuclear Information System (INIS)

    Alizai, M.N.K.; Abid, H.

    2008-01-01

    White potatoes (Solanum turberosum) were procured from agriculture Research Institute Tarnab Farm Peshawar to use for the preparation of potato powder. The process involves sorting. Washing, peeling slicing, blanching, treating with poly phenol oxidase inhibitors, dehydration, grinding and packing. All these parameters used in process were standardized. Chemical analysis of fresh potato and potato powder were carried out. Microbiological examination, functional properties and storage life studies of the potato powder were also performed. The product prepared by drying in cabinet dryer at 55 C for 7 hours was off white colour potatoes chips which was grinded to make off white potato powder. The potato powder possessed taste and texture. (author)

  13. Direct analysis in real time-Mass spectrometry (DART-MS) in forensic and security applications.

    Science.gov (United States)

    Pavlovich, Matthew J; Musselman, Brian; Hall, Adam B

    2018-03-01

    Over the last decade, direct analysis in real time (DART) has emerged as a viable method for fast, easy, and reliable "ambient ionization" for forensic analysis. The ability of DART to generate ions from chemicals that might be present at the scene of a criminal activity, whether they are in the gas, liquid, or solid phase, with limited sample preparation has made the technology a useful analytical tool in numerous forensic applications. This review paper summarizes many of those applications, ranging from the analysis of trace evidence to security applications, with a focus on providing the forensic scientist with a resource for developing their own applications. The most common uses for DART in forensics are in studying seized drugs, drugs of abuse and their metabolites, bulk and detonated explosives, toxic chemicals, chemical warfare agents, inks and dyes, and commercial plant and animal products that have been adulterated for economic gain. This review is meant to complement recent reviews that have described the fundamentals of the ionization mechanism and the general use of DART. We describe a wide range of forensic applications beyond the field of analyzing drugs of abuse, which dominates the literature, including common experimental and data analysis methods. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:171-187, 2018. © 2016 Wiley Periodicals, Inc.

  14. QUALITY ASSURANCE GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    Science.gov (United States)

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following quality assurance guidelines to provide laboratories engaged in forensic analysis of chemical evidence associated with terrorism a framework to implement a quality assura...

  15. Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water.

    Science.gov (United States)

    Morandi, Garrett D; Wiseman, Steve B; Pereira, Alberto; Mankidy, Rishikesh; Gault, Ian G M; Martin, Jonathan W; Giesy, John P

    2015-10-20

    Acute toxicity of oil sands process-affected water (OSPW) is caused by its complex mixture of bitumen-derived organics, but the specific chemical classes that are most toxic have not been demonstrated. Here, effects-directed analysis was used to determine the most acutely toxic chemical classes in OSPW collected from the world's first oil sands end-pit lake. Three sequential rounds of fractionation, chemical analysis (ultrahigh resolution mass spectrometry), and acute toxicity testing (96 h fathead minnow embryo lethality and 15 min Microtox bioassay) were conducted. Following primary fractionation, toxicity was primarily attributable to the neutral extractable fraction (F1-NE), containing 27% of original organics mass. In secondary fractionation, F1-NE was subfractionated by alkaline water washing, and toxicity was primarily isolated to the ionizable fraction (F2-NE2), containing 18.5% of the original organic mass. In the final round, chromatographic subfractionation of F2-NE2 resulted in two toxic fractions, with the most potent (F3-NE2a, 11% of original organic mass) containing predominantly naphthenic acids (O2(-)). The less-toxic fraction (F3-NE2b, 8% of original organic mass) contained predominantly nonacid species (O(+), O2(+), SO(+), NO(+)). Evidence supports naphthenic acids as among the most acutely toxic chemical classes in OSPW, but nonacidic species also contribute to acute toxicity of OSPW.

  16. Some comments on misuse of terms related to chemical analysis

    International Nuclear Information System (INIS)

    Steinnes, E.

    2007-01-01

    Complet text of publication follows. I have been involved in scientific studies involving chemical analysis for more than 49 years. Over this period I have observed an increasing tendency to incorrect use of terms 'analysis' and 'determination' and the corresponding verbum forms. According to correct terminology in English, samples are analyzed, analytes (e.g., trace elements) are determined. However, too often expressions such as 'analysis of copper in blood' are seen in the literature, especially in papers written by non-chemists. The reason why I am raising this point at the present time in that I observed the problem in several recent titles of papers published over the last few years in the Journal of Radioanalytical and Nuclear Chemistry: Preconcentration and neutron activation analysis of thorium and uranium in natural waters. Use of activated carbon as pre-separation agent in NAA of selenium, cobalt and iodine. Recent developments in the analysis of transuranics (Np, Pu, Am) in sea water. Automated radiochemical analysis of total 99 Tc in aged nuclear waste processing streams. Photon activation analysis of carbon in glasses for fiber amplifiers by using the flow method for the rapid separation of 11 C. Preconcentration neutron activation analysis of lanthanides by cloudpoint extraction using PAN. Analysis of the chemical elements in leaves infected by fumagina by X-ray fluorescence technique. Rapid method for 226 Ra and 228 Ra analysis in water samples. The above list is far from exhaustive. I believe that this incorrect use of terminology should be avoided at least in the titles of scientific papers, in Journal of Radioanalytical and Nuclear Chemistry as well as in other scientific journals. In some of the above cases replacing 'of' with 'for the determination of', or just with 'for', would have solved the problem. In other cases it would be preferable to reverse the order of words in the sentence, such as e.g., 'Determination of selenium, cobalt and

  17. Thermal and Chemical Characterization of Non-Metallic Materials Using Coupled Thermogravimetric Analysis and Infrared Spectroscopy

    Science.gov (United States)

    Huff, Timothy L.

    2002-01-01

    Thermogravimetric analysis (TGA) is widely employed in the thermal characterization of non-metallic materials, yielding valuable information on decomposition characteristics of a sample over a wide temperature range. However, a potential wealth of chemical information is lost during the process, with the evolving gases generated during thermal decomposition escaping through the exhaust line. Fourier Transform-Infrared spectroscopy (FT-IR) is a powerful analytical technique for determining many chemical constituents while in any material state, in this application, the gas phase. By linking these two techniques, evolving gases generated during the TGA process are directed into an appropriately equipped infrared spectrometer for chemical speciation. Consequently, both thermal decomposition and chemical characterization of a material may be obtained in a single sample run. In practice, a heated transfer line is employed to connect the two instruments while a purge gas stream directs the evolving gases into the FT-IR. The purge gas can be either high purity air or an inert gas such as nitrogen to allow oxidative and pyrolytic processes to be examined, respectively. The FT-IR data is collected realtime, allowing continuous monitoring of chemical compositional changes over the course of thermal decomposition. Using this coupled technique, an array of diverse materials has been examined, including composites, plastics, rubber, fiberglass epoxy resins, polycarbonates, silicones, lubricants and fluorocarbon materials. The benefit of combining these two methodologies is of particular importance in the aerospace community, where newly developing materials have little available data with which to refer. By providing both thermal and chemical data simultaneously, a more definitive and comprehensive characterization of the material is possible. Additionally, this procedure has been found to be a viable screening technique for certain materials, with the generated data useful in

  18. Thermodynamic analysis of direct internal reforming of methane and butane in proton and oxygen conducting fuel cells

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Geerlings, J.J.C.

    2008-01-01

    We present results of a thermodynamic analysis of direct internal reforming fuel cells, based on either a proton conducting fuel cell (FC-H+) or an oxygen ion conducting fuel cell (FC-O2-). We analyze the option of methane as fuel as well as butane. The model self-consistently combines all chemical

  19. Comparison of descriptive sensory analysis and chemical analysis for oxidative changes in milk

    DEFF Research Database (Denmark)

    Hedegaard, R V; Kristensen, D; Nielsen, Jacob Holm

    2006-01-01

    and lipolytic changes occurring in the milk during chill storage for 4 d. Sensory analysis and chemical analysis showed high correlation between the typical descriptors for oxidation such as cardboard, metallic taste, and boiled milk and specific chemical markers for oxidation such as hexanal. Notably, primary......Oxidation in 3 types of bovine milk with different fatty acid profiles obtained through manipulation of feed was evaluated by analytical methods quantifying the content of potential antioxidants, the tendency of formation of free radicals, and the accumulation of primary and secondary oxidation...... products. The milk samples were evaluated in parallel by descriptive sensory analysis by a trained panel, and the correlation between the chemical analysis and the descriptive sensory analysis was evaluated. The fatty acid composition of the 3 types of milk was found to influence the oxidative...

  20. Comparison of descriptive sensory analysis and chemical analysis for oxidative changes in milk

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Kristensen, D.; Nielsen, J. H.

    2006-01-01

    products. The milk samples were evaluated in parallel by descriptive sensory analysis by a trained panel, and the correlation between the chemical analysis and the descriptive sensory analysis was evaluated. The fatty acid composition of the 3 types of milk was found to influence the oxidative...... and lipolytic changes occurring in the milk during chill storage for 4 d. Sensory analysis and chemical analysis showed high correlation between the typical descriptors for oxidation such as cardboard, metallic taste, and boiled milk and specific chemical markers for oxidation such as hexanal. Notably, primary...... oxidation products (i.e., lipid hydroperoxides) and even the tendency of formation of radicals as measured by electron spin resonance spectroscopy were also highly correlated to the sensory descriptors for oxidation. Electron spin resonance spectroscopy should accordingly be further explored as a routine...

  1. Chemical effects in materials studies using Auger analysis

    International Nuclear Information System (INIS)

    Rye, R.R.

    1985-01-01

    Core-valence-valence Auger spectra (AES) afford a unique local view of valence electron structure. The direct involvement in the Auger process of both core and valence states means that the transition matrix element will have a large value only for that portion of the valence electron density which covers the same spatial extent as the core wave function. Thus, the information content of AES is local to the atomic site containing the initial core hole. Our approach in understanding the local information content of AES has been mainly experimental through the intercomparison of model systems, both molecular and solid. The use of molecules in this regard is particularly useful since the vast array of molecular species of known geometric and electronic structures allows one to both vary these properties in a systematic fashion to observe trends and to choose a molecule to probe a specific chemical question

  2. Trend analysis of the wave storminess: the wave direction

    Science.gov (United States)

    Casas Prat, M.; Sierra, J. P.; Mösso, C.; Sánchez-Arcilla, A.

    2009-09-01

    directionality. It is based on 44 year hindcast model data (1958-2001) of the HIPOCAS project, enabling to work with a longer time series compared to the existing measured ones. 41 nodes of this database are used, containing 3 hourly simulated data of significant wave height and wave direction, among other parameters. For storm definition, the Peak Over Threshold (POT) method is used with some additional duration requirements in order to analyse statistically independent events (Mendoza & Jiménez, 2006). Including both wave height and storm duration, the wave storminess is characterised by the energy content (Mendoza & Jiménez, 2004), being in turn log-transformed because of its positive scale. Separately, the wave directionality itself is analysed in terms of different sectors and approaching their probability of occurrence by counting events and using Bayesian inference (Agresti, 2002). Therefore, the original data is transformed into compositional data and, before performing the trend analysis, the isometric logratio (ilr) transformation (Egozcue et al., 2003) is done. In general, the trend analysis methodology consists in two steps: 1) trend detection and 2) trend quantification. For 1) the Mann Kendall test is used in order to identify the nodes with significant trend. For these selected nodes, the trend quantification is done, comparing two methods: 1) a simple linear regression analysis complemented with the bootstrap technique and 2) a Bayesian analysis, assuming normally distributed data with linearly increasing mean. Preliminary results show no significant trend for both annual mean and maximum energy content except for some nodes located to the Northern Catalan coast. Regarding the wave direction (but not only considering stormy conditions) there is a tendency of North direction to decrease whereas South and Southeast direction seems to increase.

  3. Effect-directed analysis supporting monitoring of aquatic environments--An in-depth overview.

    Science.gov (United States)

    Brack, Werner; Ait-Aissa, Selim; Burgess, Robert M; Busch, Wibke; Creusot, Nicolas; Di Paolo, Carolina; Escher, Beate I; Mark Hewitt, L; Hilscherova, Klara; Hollender, Juliane; Hollert, Henner; Jonker, Willem; Kool, Jeroen; Lamoree, Marja; Muschket, Matthias; Neumann, Steffen; Rostkowski, Pawel; Ruttkies, Christoph; Schollee, Jennifer; Schymanski, Emma L; Schulze, Tobias; Seiler, Thomas-Benjamin; Tindall, Andrew J; De Aragão Umbuzeiro, Gisela; Vrana, Branislav; Krauss, Martin

    2016-02-15

    Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone but tools are required to reduce this complexity and identify those chemicals that might cause adverse effects. Effect-directed analysis (EDA) is designed to meet this challenge and faces increasing interest in water and sediment quality monitoring. Thus, the present paper summarizes current experience with the EDA approach and the tools required, and provides practical advice on their application. The paper highlights the need for proper problem formulation and gives general advice for study design. As the EDA approach is directed by toxicity, basic principles for the selection of bioassays are given as well as a comprehensive compilation of appropriate assays, including their strengths and weaknesses. A specific focus is given to strategies for sampling, extraction and bioassay dosing since they strongly impact prioritization of toxicants in EDA. Reduction of sample complexity mainly relies on fractionation procedures, which are discussed in this paper, including quality assurance and quality control. Automated combinations of fractionation, biotesting and chemical analysis using so-called hyphenated tools can enhance the throughput and might reduce the risk of artifacts in laboratory work. The key to determining the chemical structures causing effects is analytical toxicant identification. The latest approaches, tools, software and databases for target-, suspect and non-target screening as well as unknown identification are discussed together with analytical and toxicological confirmation approaches. A better understanding of optimal use and combination of EDA tools will help to design efficient and successful toxicant identification studies in the context of quality monitoring in multiply stressed environments. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  5. ANALYSIS OF CHEMICAL COMPOUNDS DISTINGUISHER FOR AGARWOOD QUALITIES

    Directory of Open Access Journals (Sweden)

    Gunawan Trisandi Pasaribu

    2015-04-01

    Full Text Available Gaharu (Agarwood is described as a fragrant-smelling wood that is usually derived from the trunk of the genus Aquilaria and Gyrinops (both of the family Thymelaeaceae, which have been infected by a particular disease. Based on Indonesian National Standard, agarwood can be classified into various grades, i.e. gubal gaharu, kemedangan and serbuk gaharu. The grading system is based on the color, weight and odor. It seems that such a grading is too subjective for agarwood classification. Therefore, to minimize the subjectivity, more objective agarwood grading is required, which incorporates its chemical composition and resin content. This research was conducted focusing on the analysis of the particular grade of agarwood originating from West Sumatra. The different types of agarwood qualities are: kemedangan C, teri C, kacangan C and super AB. Initially, the obtained agarwood samples were grounded to powder, extracted on a Soxhlet extractor using various organic solvents (i.e. n-hexane, acetone, and methanol. The agarwood-acetone extracts were analyzed using GC-MS to determine its chemical composition. The results showed a positive, linier relationship in which the resin yield increased with the increase in agarwood quality grades. GC-MS analysis revealed that several sesquiterpene groups can be found in kemedangan C, teri C, kacangan C and super AB qualities. It is interesting that aromadendrene could be identified or found in all agarwood quality grades. Therefore, it is presumed that the aromadendrene compounds can act as an effective chemical distinguisher for agarwood, whereby the greater the aromadendrene content, the better is the agarwood grade.

  6. Microbiological and chemical analysis of land snails commercialised in Sicily

    Directory of Open Access Journals (Sweden)

    Antonello Cicero

    2015-05-01

    Full Text Available In this study 160 samples of snails belonging to the species Helix aspersa maxima and Helix aspersa muller were examined for chemical and microbiological analysis. Samples came from Greece and Poland. Results showed mean concentration of cadmium (0.35±0.036 mg/kg and lead (0.05±0.013 mg/kg much higher than the limit of detection. Mercury levels in both species were not detected. Microbiological analysis revealed the absence of Salmonella spp. and Clostridium spp. in both examined species. E. coli and K. oxytoca were observed in Helix aspersa maxima and Helix aspersa muller. Furthermore, one case of fungi positivity in samples of Helix aspersa muller was found. The reported investigations highlight the need to create and adopt a reference legislation to protect the health of consumers.

  7. Chemical analysis for waste management in paint industries

    International Nuclear Information System (INIS)

    Nawaz, Z.; Naveed, S.; Shiekh, N.A.; Sagheer, K.

    2005-01-01

    The chemical analysis of paint industries waste has been carried out; the main emission sources are the heating of raw materials and lacquer. Also the waste from other applications and production contains high concentration of heavy metals, VOC's, COD, TDS with notable acidity and alkalinity. Based on the analysis it was observed that the major losses of production could be minimized. Further toxic effects of the waste material can be minimized. In this reference measures to minimize production losses should be adopted along with the proper management. These laboratory results also lead to the areas of emissions and waste production during manufacturing process. Solutions have been proposed for process development and integrated waste minimization. (author)

  8. Cosmetics chemical composition characterization by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Ana Paula; Pereira, Gustavo Jose; Amaral, Angela Maria; Ferreira, Andrea Vidal, E-mail: ana_allves2008@hotmail.co [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    Brazil is in the third position in the world's cosmetics market. It is an expanding and growing market where new products and manufacturing processes are in a constant and steady expansion. Therefore, it is mandatory that the composition of the products is well known in order to guarantee safety and quality of daily used cosmetics. The Brazilian National Health Surveillance Agency (ANVISA) has issued a resolution, RDC No. 48, March 16, 2006, which defines a 'List of Substances which can not be used in personal hygiene products, cosmetics and perfumes'. In this work, samples of locally manufactured and imported cosmetics (lipsticks, eye shadows, etc.) were analyzed using the Instrumental Neutron Activation Analysis technique. The samples were irradiated in the TRIGA IPR-R1 reactor of the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), on a 100kW thermal power, with a thermal neutron fluence rate about 8x10{sup 11}ncm{sup -2}s{sup -1}. The analysis has detected the chemical elements Br, Ba, Ga, Na, K, Sc, Fe, Cr, Zn, Sm, W, La, Rb, Cs, Ta, Ge, Co, U, Ti, V, Cl, Al, Mn and Cu. The concentrations of these elements are on a range from 5 to 3000mug.g{sup -1}. Some chemical elements observed in samples (Cl, Br, Cr, U) are included at ANVISA prohibitive list. (author)

  9. Cosmetics chemical composition characterization by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Alves, Ana Paula; Pereira, Gustavo Jose; Amaral, Angela Maria; Ferreira, Andrea Vidal

    2009-01-01

    Brazil is in the third position in the world's cosmetics market. It is an expanding and growing market where new products and manufacturing processes are in a constant and steady expansion. Therefore, it is mandatory that the composition of the products is well known in order to guarantee safety and quality of daily used cosmetics. The Brazilian National Health Surveillance Agency (ANVISA) has issued a resolution, RDC No. 48, March 16, 2006, which defines a 'List of Substances which can not be used in personal hygiene products, cosmetics and perfumes'. In this work, samples of locally manufactured and imported cosmetics (lipsticks, eye shadows, etc.) were analyzed using the Instrumental Neutron Activation Analysis technique. The samples were irradiated in the TRIGA IPR-R1 reactor of the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), on a 100kW thermal power, with a thermal neutron fluence rate about 8x10 11 ncm -2 s -1 . The analysis has detected the chemical elements Br, Ba, Ga, Na, K, Sc, Fe, Cr, Zn, Sm, W, La, Rb, Cs, Ta, Ge, Co, U, Ti, V, Cl, Al, Mn and Cu. The concentrations of these elements are on a range from 5 to 3000μg.g -1 . Some chemical elements observed in samples (Cl, Br, Cr, U) are included at ANVISA prohibitive list. (author)

  10. An effect-directed strategy for characterizing emerging chemicals in food contact materials made from paper and board

    DEFF Research Database (Denmark)

    Rosenmai, Anna Kjerstine; Bengtström, Linda; Taxvig, Camilla

    2017-01-01

    Food contact materials (FCM) are any type of item intended to come into contact with foods and thus represent a potential source for human exposure to chemicals. Regarding FCMs made of paper and board, information pertaining to their chemical constituents and the potential impacts on human health...... FCMs exhibited activities in at least one assay. As proof-of-principle, FCM samples obtained from a sandwich wrapper and a pizza box were carried through a complete step-by-step multi-tiered approach. The pizza box exhibited ER activity, likely caused by the presence of bisphenol A, dibutyl phthalate......, and benzylbutyl phthalate. The sandwich wrapper exhibited AR antagonism, likely caused by abietic acid and dehydroabietic acid. Migration studies confirmed that the active chemicals can transfer from FCMs to food simulants. In conclusion, we report an effect-directed strategy that can identify hazards posed...

  11. Evaluating the risks of clinical research: direct comparative analysis.

    Science.gov (United States)

    Rid, Annette; Abdoler, Emily; Roberson-Nay, Roxann; Pine, Daniel S; Wendler, David

    2014-09-01

    Many guidelines and regulations allow children and adolescents to be enrolled in research without the prospect of clinical benefit when it poses minimal risk. However, few systematic methods exist to determine when research risks are minimal. This situation has led to significant variation in minimal risk judgments, raising concern that some children are not being adequately protected. To address this concern, we describe a new method for implementing the widely endorsed "risks of daily life" standard for minimal risk. This standard defines research risks as minimal when they do not exceed the risks posed by daily life activities or routine examinations. This study employed a conceptual and normative analysis, and use of an illustrative example. Different risks are composed of the same basic elements: Type, likelihood, and magnitude of harm. Hence, one can compare the risks of research and the risks of daily life by comparing the respective basic elements with each other. We use this insight to develop a systematic method, direct comparative analysis, for implementing the "risks of daily life" standard for minimal risk. The method offers a way of evaluating research procedures that pose the same types of risk as daily life activities, such as the risk of experiencing anxiety, stress, or other psychological harm. We thus illustrate how direct comparative analysis can be applied in practice by using it to evaluate whether the anxiety induced by a respiratory CO2 challenge poses minimal or greater than minimal risks in children and adolescents. Direct comparative analysis is a systematic method for applying the "risks of daily life" standard for minimal risk to research procedures that pose the same types of risk as daily life activities. It thereby offers a method to protect children and adolescents in research, while ensuring that important studies are not blocked because of unwarranted concerns about research risks.

  12. Analysis of the theoretical bias in dark matter direct detection

    International Nuclear Information System (INIS)

    Catena, Riccardo

    2014-01-01

    Fitting the model ''A'' to dark matter direct detection data, when the model that underlies the data is ''B'', introduces a theoretical bias in the fit. We perform a quantitative study of the theoretical bias in dark matter direct detection, with a focus on assumptions regarding the dark matter interactions, and velocity distribution. We address this problem within the effective theory of isoscalar dark matter-nucleon interactions mediated by a heavy spin-1 or spin-0 particle. We analyze 24 benchmark points in the parameter space of the theory, using frequentist and Bayesian statistical methods. First, we simulate the data of future direct detection experiments assuming a momentum/velocity dependent dark matter-nucleon interaction, and an anisotropic dark matter velocity distribution. Then, we fit a constant scattering cross section, and an isotropic Maxwell-Boltzmann velocity distribution to the simulated data, thereby introducing a bias in the analysis. The best fit values of the dark matter particle mass differ from their benchmark values up to 2 standard deviations. The best fit values of the dark matter-nucleon coupling constant differ from their benchmark values up to several standard deviations. We conclude that common assumptions in dark matter direct detection are a source of potentially significant bias

  13. Fuel spray combustion of waste cooking oil and palm oil biodiesel: Direct photography and detailed chemical kinetics

    KAUST Repository

    Kuti, Olawole

    2013-10-14

    This paper studies the ignition processes of two biodiesel from two different feedstock sources, namely waste cooked oil (WCO) and palm oil (PO). They were investigated using the direct photography through high-speed video observations and detailed chemical kinetics. The detailed chemical kinetics modeling was carried out to complement data acquired using the high-speed video observations. For the high-speed video observations, an image intensifier combined with OH* filter connected to a high-speed video camera was used to obtain OH* chemiluminscence image near 313 nm. The OH* images were used to obtain the experimental ignition delay of the biodiesel fuels. For the high-speed video observations, experiments were done at an injection pressure of 100, 200 and 300 MPa using a 0.16 mm injector nozzle. Also a detailed chemical kinetics for the biodiesel fuels was carried out using ac chemical kinetics solver adopting a 0-D reactor model to obtain the chemical ignition delay of the combusting fuels. Equivalence ratios obtained from the experimental ignition delay were used for the detailed chemical kinetics analyses. The Politecnico di Milano\\'s thermochemical and reaction kinetic data were adopted to simulate the ignition processes of the biodiesels using the five fatty acid methyl esters (FAME) major components in the biodiesel fuels. From the high-speed video observations, it was observed that at increasing injection pressure, experimental ignition delay increased as a result of improvement in fuel and air mixing effects. Also the palm oil biodiesel has a shorter ignition delay compared to waste cooked oil biodiesel. This phenomenon could be attributed to the higher cetane number of palm biodiesel. The fuel spray ignition properties depend on both the physical ignition delay and chemical ignition delay. From the detailed chemical kinetic results it was observed that at the low temperature, high ambient pressure conditions reactivity increased as equivalent ratio

  14. Fuel spray combustion of waste cooking oil and palm oil biodiesel: Direct photography and detailed chemical kinetics

    KAUST Repository

    Kuti, Olawole; Nishida, Keiya; Sarathy, Mani; Zhu, Jingyu

    2013-01-01

    This paper studies the ignition processes of two biodiesel from two different feedstock sources, namely waste cooked oil (WCO) and palm oil (PO). They were investigated using the direct photography through high-speed video observations and detailed chemical kinetics. The detailed chemical kinetics modeling was carried out to complement data acquired using the high-speed video observations. For the high-speed video observations, an image intensifier combined with OH* filter connected to a high-speed video camera was used to obtain OH* chemiluminscence image near 313 nm. The OH* images were used to obtain the experimental ignition delay of the biodiesel fuels. For the high-speed video observations, experiments were done at an injection pressure of 100, 200 and 300 MPa using a 0.16 mm injector nozzle. Also a detailed chemical kinetics for the biodiesel fuels was carried out using ac chemical kinetics solver adopting a 0-D reactor model to obtain the chemical ignition delay of the combusting fuels. Equivalence ratios obtained from the experimental ignition delay were used for the detailed chemical kinetics analyses. The Politecnico di Milano's thermochemical and reaction kinetic data were adopted to simulate the ignition processes of the biodiesels using the five fatty acid methyl esters (FAME) major components in the biodiesel fuels. From the high-speed video observations, it was observed that at increasing injection pressure, experimental ignition delay increased as a result of improvement in fuel and air mixing effects. Also the palm oil biodiesel has a shorter ignition delay compared to waste cooked oil biodiesel. This phenomenon could be attributed to the higher cetane number of palm biodiesel. The fuel spray ignition properties depend on both the physical ignition delay and chemical ignition delay. From the detailed chemical kinetic results it was observed that at the low temperature, high ambient pressure conditions reactivity increased as equivalent ratio

  15. Direct chemical reduction of neptunium oxide to neptunium metal using calcium and calcium chloride

    International Nuclear Information System (INIS)

    Squires, Leah N.; Lessing, Paul

    2016-01-01

    A process of direct reduction of neptunium oxide to neptunium metal using calcium metal as the reducing agent is discussed. After reduction of the oxide to metal, the metal is separated by density from the other components of the reaction mixture and can be easily removed upon cooling. The direct reduction technique consistently produces high purity (98%–99% pure) neptunium metal.

  16. Moral theological analysis of direct versus indirect abortion.

    Science.gov (United States)

    Haas, John M

    2017-08-01

    Cases of a vital conflict, where the lives of both the mother and child are at risk during pregnancy, have been the subject of recent vigorous debate. The basic principles put forth in the Ethical and Religious Directives are reviewed, as is the principle of double effect. An illustrative case of severe cardiomyopathy in a pregnant woman is described and it is noted that the principle of double effect would not apply. Counter arguments are noted, focusing on Martin Rhonheimer who posits that in the case of vital conflicts, such as performing a craniotomy on a baby stuck in the birth canal, taking the baby's life does not constitute a direct abortion because moral norms do not apply in the extreme conflict situation where both mother and child will die. He states that the death of the fetus is not intentional in these cases. He overlooks "how the life is being saved" and that a choice has been made, which implies a moral act, not just a physical one. Rhonheimer wants to make his moral judgment solely on the basis of intention, prescinding from what actually occurs in the physical world of cause and effect. This is clearly against the teaching in Evangelium vitae. Ethics deal with the deliberate chosen actions in space and time of embodied human beings; it deals inescapably with material actions, with specifications of intentions. Rhonheimer states, "a killing or an abortion is 'direct,' not because the death of the fetus is caused in some physically direct way, but because it is willed as the means to an end." However the death of the child cannot be excluded from the act and is therefore of necessity included in it. What the acting person chooses includes what happens physically in this act. If the action theory proposed by Rhonheimer is accepted, it could be very difficult to avoid death-dealing actions from taking place in Catholic hospitals. This is a moral analysis of cases of "vital conflicts," where the lives of both the mother and child are at risk during a

  17. Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide

    DEFF Research Database (Denmark)

    Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

    2012-01-01

    Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes...

  18. The One-Pot Directed Assembly of Cylinder-Forming Block Copolymer on Adjacent Chemical Patterns for Bimodal Patterning.

    Science.gov (United States)

    Chang, Tzu-Hsuan; Xiong, Shisheng; Liu, Chi-Chun; Liu, Dong; Nealey, Paul F; Ma, Zhenqiang

    2017-09-01

    The direct self-assembly of cylinder-forming poly(styrene-block-methyl-methacrylate) (PS-b-PMMA) block copolymer is successfully assembled into two orientations, according to the underlying guiding pattern in different areas. Lying-down and perpendicular cylinders are formed, respectively, depending on the design of chemical pattern: sparse line/space pattern or hexagonal dot array. The first chemical pattern composed of prepatterned cross-linked polystyrene (XPS) line/space structure has a period (L S ) equal to twice the intercylinder period of the block copolymer (L 0 ). The PS-b-PMMA thin film on the prepared chemical template after thermal annealing forms a lying-down cylinder morphology when the width of the PS strips is less than the width of PS block in the PS-b-PMMA block copolymer. The morphology is only applicable at the discrete thickness of the PS-b-PMMA film. In addition to forming the lying-down cylinders directly on the XPS guiding pattern, the cylinder-forming block copolymer can also be assembled in a perpendicular way on the second guiding pattern (the hexagonal dot array). The block copolymer films are registered into two orientations in a single directed self-assembly process. The features of the assembled patterns are successfully transferred down to the silicon oxide substrate. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Uranium complexes with macrosyclic polyethers. Synthesis and structural chemical analysis

    International Nuclear Information System (INIS)

    Elbasyouny, A.

    1983-01-01

    This dissertation reports about studies on the chemical coordination behaviour of uranium of oxidation stages IV and VI with regard to twelve different macrocyclic ligands. For the preparation of the complexes, for every system a different method has been developed. The elementary analysis of the various complexes including the uranium had been done by X-ray fluorescence analysis, and the structural characterization proceeded via vibrational, uv-vis and emission spectroscopy as well as 1 H-NMR and 13 C-spin-lattice relaxation time studies. Conformational analysis of the polyethers used allowed the structural changes in the complexes to be observed. The structural analysis of the hydrous uranium VI crown ether complexes yielded information of characteristic features of these types of complexes. The first coordination sphere of the uranyl ion with covalently bonded anion remains unchanged. As to the water content, there is a certain range. Depending upon the solvent used, the complexes have two or four H 2 O molecules per formula unit. (orig./EF) [de

  20. Single base pair mutation analysis by PNA directed PCR clamping

    DEFF Research Database (Denmark)

    Ørum, H.; Nielsen, P.E.; Egholm, M.

    1993-01-01

    A novel method that allows direct analysis of single base mutation by the polymerase chain reaction (PCR) is described. The method utilizes the finding that PNAs (peptide nucleic acids) recognize and bind to their complementary nucleic acid sequences with higher thermal stability and specificity...... allows selective amplification/suppression of target sequences that differ by only one base pair. Finally we show that PNAs can be designed in such a way that blockage can be accomplished when the PNA target sequence is located between the PCR primers....

  1. Rapid quality assessment of Radix Aconiti Preparata using direct analysis in real time mass spectrometry.

    Science.gov (United States)

    Zhu, Hongbin; Wang, Chunyan; Qi, Yao; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

    2012-11-08

    This study presents a novel and rapid method to identify chemical markers for the quality control of Radix Aconiti Preparata, a world widely used traditional herbal medicine. In the method, the samples with a fast extraction procedure were analyzed using direct analysis in real time mass spectrometry (DART MS) combined with multivariate data analysis. At present, the quality assessment approach of Radix Aconiti Preparata was based on the two processing methods recorded in Chinese Pharmacopoeia for the purpose of reducing the toxicity of Radix Aconiti and ensuring its clinical therapeutic efficacy. In order to ensure the safety and effectivity in clinical use, the processing degree of Radix Aconiti should be well controlled and assessed. In the paper, hierarchical cluster analysis and principal component analysis were performed to evaluate the DART MS data of Radix Aconiti Preparata samples in different processing times. The results showed that the well processed Radix Aconiti Preparata, unqualified processed and the raw Radix Aconiti could be clustered reasonably corresponding to their constituents. The loading plot shows that the main chemical markers having the most influence on the discrimination amongst the qualified and unqualified samples were mainly some monoester diterpenoid aconitines and diester diterpenoid aconitines, i.e. benzoylmesaconine, hypaconitine, mesaconitine, neoline, benzoylhypaconine, benzoylaconine, fuziline, aconitine and 10-OH-mesaconitine. The established DART MS approach in combination with multivariate data analysis provides a very flexible and reliable method for quality assessment of toxic herbal medicine. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Chemical and physical factors which control the substitution reactions of direct fission-produced iodine with gaseous methane and the methyl halides

    International Nuclear Information System (INIS)

    Kikuchi, M.; Church, L.B.

    1976-01-01

    The factors controlling the hydrogen and halogen substitution reactions resulting from direct fission-produced iodine isotopes (*I) with gaseous methane and methyl halides were investigated. The chemical reaction probabilities, corrected for any secondary decomposition, were compared as a function of various chemical and physical parameters. These include carbon-halogen bond strength, halogen electronegativity, volume and cross sectional area of the substituted and neighboring atoms. On the basis of this analysis, it is concluded that *I-for-X (where X = H, F, Cl, Br and I) substitution reactions are controlled by the cross sectional area of the X atom. The *I-for-H substitution probability is reduced in proportion to the volume of X, suggesting that steric interference is the dominant factor influencing the reaction probability. (orig.) [de

  3. ANALYSIS OF THERMAL-CHEMICAL CHARACTERISTICS OF BIOMASS ENERGY PELLETS

    Directory of Open Access Journals (Sweden)

    Zorica Gluvakov

    2014-09-01

    Full Text Available In modern life conditions, when emphasis is on environmental protection and sustainable development, fuels produced from biomass are increasingly gaining in importance, and it is necessary to consider the quality of end products obtained from biomass. Based on the existing European standards, collected literature and existing laboratory methods, this paper presents results of testing individual thermal - chemical properties of biomass energy pellets after extrusion and cooling the compressed material. Analysing samples based on standard methods, data were obtained on the basis of which individual thermal-chemical properties of pellets were estimated. Comparing the obtained results with the standards and literature sources, it can be said that moisture content, ash content and calorific values are the most important parameters for quality analysis which decide on applicability and use-value of biomass energy pellets, as biofuel. This paper also shows the impact of biofuels on the quality of environmental protection. The conclusion provides a clear statement of quality of biomass energy pellets.

  4. Methods of chemical and phase composition analysis of gallstones

    Science.gov (United States)

    Suvorova, E. I.; Pantushev, V. V.; Voloshin, A. E.

    2017-11-01

    This review presents the instrumental methods used for chemical and phase composition investigation of gallstones. A great body of data has been collected in the literature on the presence of elements and their concentrations, obtained by fluorescence microscopy, X-ray fluorescence spectroscopy, neutron activation analysis, proton (particle) induced X-ray emission, atomic absorption spectroscopy, high-resolution gamma-ray spectrometry, electron paramagnetic resonance. Structural methods—powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy—provide information about organic and inorganic phases in gallstones. Stone morphology was studied at the macrolevel with optical microscopy. Results obtained by analytical scanning and transmission electron microscopy with X-ray energy dispersive spectrometry are discussed. The chemical composition and structure of gallstones determine the strategy of removing stone from the body and treatment of patients: surgery or dissolution in the body. Therefore one chapter of the review describes the potential of dissolution methods. Early diagnosis and appropriate treatment of the disease depend on the development of clinical methods for in vivo investigation, which gave grounds to present the main characteristics and potential of ultrasonography (ultrasound scanning), magnetic resonance imaging, and X-ray computed tomography.

  5. Technique Triangulation for Validation in Directed Content Analysis

    Directory of Open Access Journals (Sweden)

    Áine M. Humble PhD

    2009-09-01

    Full Text Available Division of labor in wedding planning varies for first-time marriages, with three types of couples—traditional, transitional, and egalitarian—identified, but nothing is known about wedding planning for remarrying individuals. Using semistructured interviews, the author interviewed 14 couples in which at least one person had remarried and used directed content analysis to investigate the extent to which the aforementioned typology could be transferred to this different context. In this paper she describes how a triangulation of analytic techniques provided validation for couple classifications and also helped with moving beyond “blind spots” in data analysis. Analytic approaches were the constant comparative technique, rank order comparison, and visual representation of coding, using MAXQDA 2007's tool called TextPortraits.

  6. Multi-Directional Non-Parametric Analysis of Agricultural Efficiency

    DEFF Research Database (Denmark)

    Balezentis, Tomas

    This thesis seeks to develop methodologies for assessment of agricultural efficiency and employ them to Lithuanian family farms. In particular, we focus on three particular objectives throughout the research: (i) to perform a fully non-parametric analysis of efficiency effects, (ii) to extend...... to the Multi-Directional Efficiency Analysis approach when the proposed models were employed to analyse empirical data of Lithuanian family farm performance, we saw substantial differences in efficiencies associated with different inputs. In particular, assets appeared to be the least efficiently used input...... relative to labour, intermediate consumption and land (in some cases land was not treated as a discretionary input). These findings call for further research on relationships among financial structure, investment decisions, and efficiency in Lithuanian family farms. Application of different techniques...

  7. Validation of the direct analysis in real time source for use in forensic drug screening.

    Science.gov (United States)

    Steiner, Robert R; Larson, Robyn L

    2009-05-01

    The Direct Analysis in Real Time (DART) ion source is a relatively new mass spectrometry technique that is seeing widespread use in chemical analyses world-wide. DART studies include such diverse topics as analysis of flavors and fragrances, melamine in contaminated dog food, differentiation of writing inks, characterization of solid counterfeit drugs, and as a detector for planar chromatography. Validation of this new technique for the rapid screening of forensic evidence for drugs of abuse, utilizing the DART source coupled to an accurate mass time-of-flight mass spectrometer, was conducted. The study consisted of the determination of the lower limit of detection for the method, determination of selectivity and a comparison of this technique to established analytical protocols. Examples of DART spectra are included. The results of this study have allowed the Virginia Department of Forensic Science to incorporate this new technique into their analysis scheme for the screening of solid dosage forms of drugs of abuse.

  8. COMBUSTION ANALYSIS OF A CNG DIRECT INJECTION SPARK IGNITION ENGINE

    Directory of Open Access Journals (Sweden)

    A. Rashid A. Aziz

    2010-12-01

    Full Text Available An experimental study was carried out on a dedicated compressed natural gas direct injection (CNG-DI engine with a compression ratio (CR of 14 and a central injection system. Several injection timing parameters from early injection timing (300 BTDC to partial direct injection (180 BTDC to full direct injection (120 BTDC were investigated. The 300 BTDC injection timing experiment was carried out to simulate the performance of a port injection engine and the result is used as a benchmark for engine performance. The full DI resulted in a 20% higher performance than the early injection timing for low engine speeds up to 2750 rpm. 180 BTDC injection timing shows the highest performance over an extensive range of engine speed because it has a similar volumetric efficiency to full DI. However, the earlier injection timing allowed for a better air–fuel mixing and gives superior performance for engine speeds above 4500 rpm. The engine performance could be explained by analysis of the heat release rate that shows that at low and intermediate engine speeds of 2000 and 3000, the full DI and partial DI resulted in the fastest heat release rate whereas at a high engine speed of 5000 rpm, the simulated port injection operation resulted in the fastest heat release rate.

  9. Performance analysis of a SOFC under direct internal reforming conditions

    Energy Technology Data Exchange (ETDEWEB)

    Janardhanan, Vinod M.; Deutschmann, Olaf [Institute for Chemical Technology and Polymer Chemistry, Engesserstr 20, D-76131 Karlsruhe, University of Karlsruhe (Germany); Heuveline, Vincent [Institute for Applied and Numerical Mathematics, Kaiserstr. 12, D-76128 Karlsruhe (Germany)

    2007-10-11

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed. (author)

  10. Performance analysis of a SOFC under direct internal reforming conditions

    Science.gov (United States)

    Janardhanan, Vinod M.; Heuveline, Vincent; Deutschmann, Olaf

    This paper presents the performance analysis of a planar solid-oxide fuel cell (SOFC) under direct internal reforming conditions. A detailed solid-oxide fuel cell model is used to study the influences of various operating parameters on cell performance. Significant differences in efficiency and power density are observed for isothermal and adiabatic operational regimes. The influence of air number, specific catalyst area, anode thickness, steam to carbon (s/c) ratio of the inlet fuel, and extend of pre-reforming on cell performance is analyzed. In all cases except for the case of pre-reformed fuel, adiabatic operation results in lower performance compared to isothermal operation. It is further discussed that, though direct internal reforming may lead to cost reduction and increased efficiency by effective utilization of waste heat, the efficiency of the fuel cell itself is higher for pre-reformed fuel compared to non-reformed fuel. Furthermore, criteria for the choice of optimal operating conditions for cell stacks operating under direct internal reforming conditions are discussed.

  11. Chemical analysis and potential health risks of hookah charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, Yehya, E-mail: yelsayed@aus.edu; Dalibalta, Sarah, E-mail: sdalibalta@aus.edu; Abu-Farha, Nedal

    2016-11-01

    Hookah (waterpipe) smoking is a very common practice that has spread globally. There is growing evidence on the hazardous consequences of smoking hookah, with studies indicating that its harmful effects are comparable to cigarette smoking if not worse. Charcoal is commonly used as a heating source for hookah smoke. Although charcoal briquettes are thought to be one of the major contributors to toxicity, their composition and impact on the smoke generated remains largely unidentified. This study aims to analyze the elemental composition of five different raw synthetic and natural charcoals by using Carbon-Hydrogen-Nitrogen (CHN) analysis, inductively coupled plasma (ICP), and scanning electron microscopy coupled with energy dispersive X-Ray spectrometry (SEM-EDS). Elemental analysis showed that the raw charcoals contain heavy metals such as zinc, iron, cadmium, vanadium, aluminum, lead, chromium, manganese and cobalt at concentrations similar, if not higher than, cigarettes. In addition, thermal desorption-gas chromatography–mass spectrometry (TD-GC–MS) was used to analyze the chemical composition of the smoke produced from burning the charcoal samples. The smoke emitted from charcoal was found to be the source of numerous compounds which could be hazardous to health. A total of seven carcinogens, 39 central nervous system depressants and 31 respiratory irritants were identified. - Highlights: • Hookah charcoals, mainly synthetic brands, contains trace/heavy metals in concentrations exceeding those in cigarettes. • The concentration of lead in synthetic charcoal briquettes may impose adverse effects on human health. • The amount of nitrogen in synthetic charcoal is comparable to that reported in cigarettes. • Chemical profiling of smoke emitted from hookah charcoal reveals many compounds associated with potential health risks.

  12. Chemical analysis and potential health risks of hookah charcoal

    International Nuclear Information System (INIS)

    Elsayed, Yehya; Dalibalta, Sarah; Abu-Farha, Nedal

    2016-01-01

    Hookah (waterpipe) smoking is a very common practice that has spread globally. There is growing evidence on the hazardous consequences of smoking hookah, with studies indicating that its harmful effects are comparable to cigarette smoking if not worse. Charcoal is commonly used as a heating source for hookah smoke. Although charcoal briquettes are thought to be one of the major contributors to toxicity, their composition and impact on the smoke generated remains largely unidentified. This study aims to analyze the elemental composition of five different raw synthetic and natural charcoals by using Carbon-Hydrogen-Nitrogen (CHN) analysis, inductively coupled plasma (ICP), and scanning electron microscopy coupled with energy dispersive X-Ray spectrometry (SEM-EDS). Elemental analysis showed that the raw charcoals contain heavy metals such as zinc, iron, cadmium, vanadium, aluminum, lead, chromium, manganese and cobalt at concentrations similar, if not higher than, cigarettes. In addition, thermal desorption-gas chromatography–mass spectrometry (TD-GC–MS) was used to analyze the chemical composition of the smoke produced from burning the charcoal samples. The smoke emitted from charcoal was found to be the source of numerous compounds which could be hazardous to health. A total of seven carcinogens, 39 central nervous system depressants and 31 respiratory irritants were identified. - Highlights: • Hookah charcoals, mainly synthetic brands, contains trace/heavy metals in concentrations exceeding those in cigarettes. • The concentration of lead in synthetic charcoal briquettes may impose adverse effects on human health. • The amount of nitrogen in synthetic charcoal is comparable to that reported in cigarettes. • Chemical profiling of smoke emitted from hookah charcoal reveals many compounds associated with potential health risks.

  13. Ion Mobility Mass Spectrometry Direct Isotope Abundance Analysis

    International Nuclear Information System (INIS)

    Manard, Manuel J.; Weeks, Stephan; Kyle, Kevin

    2010-01-01

    The nuclear forensics community is currently engaged in the analysis of illicit nuclear or radioactive material for the purposes of non-proliferations and attribution. One technique commonly employed for gathering nuclear forensics information is isotope analysis. At present, the state-of-the-art methodology for obtaining isotopic distributions is thermal ionization mass spectrometry (TIMS). Although TIMS is highly accurate at determining isotope distributions, the technique requires an elementally pure sample to perform the measurement. The required radiochemical separations give rise to sample preparation times that can be in excess of one to two weeks. Clearly, the nuclear forensics community is in need of instrumentation and methods that can expedite their decision making process in the event of a radiological release or nuclear detonation. Accordingly, we are developing instrumentation that couples a high resolution IM drift cell to the front end of a MS. The IM cell provides a means of separating ions based upon their collision cross-section and mass-to-charge ratio (m/z). Two analytes with the same m/z, but with different collision cross-sections (shapes) would exit the cell at different times, essentially enabling the cell to function in a similar manner to a gas chromatography (GC) column. Thus, molecular and atomic isobaric interferences can be effectively removed from the ion beam. The mobility selected chemical species could then be introduced to a MS for high-resolution mass analysis to generate isotopic distributions of the target analytes. The outcome would be an IM/MS system capable of accurately measuring isotopic distributions while concurrently eliminating isobaric interferences and laboratory radiochemical sample preparation. The overall objective of this project is developing instrumentation and methods to produce near real-time isotope distributions with a modular mass spectrometric system that performs the required gas-phase chemistry and

  14. Petroleomics by Direct Analysis in Real Time-Mass Spectrometry.

    Science.gov (United States)

    Romão, Wanderson; Tose, Lilian V; Vaz, Boniek G; Sama, Sara G; Lobinski, Ryszard; Giusti, Pierre; Carrier, Hervé; Bouyssiere, Brice

    2016-01-01

    The analysis of crude oil and its fractions by applying ambient ionization techniques remains underexplored in mass spectrometry (MS). Direct analysis in real time (DART) in the positive-ion mode was coupled to a linear quadrupole ion trap Orbitrap mass spectrometer (LTQ Orbitrap) to analyze crude oil, paraffin samples, and porphyrin standard compounds. The ionization parameters of DART-MS were optimized for crude oil analysis. DART-MS rendered the optimum conditions of the operation using paper as the substrate, T = 400°C, helium as the carrier gas, and a sample concentration ≥6 mg mL(-1). In the crude oils analysis, the DART(+)-Orbitrap mass spectra detected the typical N, NO, and O-containing compounds. In the paraffin samples, oxidized hydrocarbon species (Ox classes, where x = 1-4) with double-bond equivalent of 1-4 were detected, and their structures and connectivity were confirmed by collision-induced dissociation (CID) experiments. DART(+)-MS has identified the porphyrin standard compounds as [M + H](+) ions of m/z 615.2502 and 680.1763, where M = C44H30N4 and C44H28N4OV, respectively, based on the formula assignment and by phenyl losses observed on CID experiments.

  15. Microarray technology for major chemical contaminants analysis in food: current status and prospects.

    Science.gov (United States)

    Zhang, Zhaowei; Li, Peiwu; Hu, Xiaofeng; Zhang, Qi; Ding, Xiaoxia; Zhang, Wen

    2012-01-01

    Chemical contaminants in food have caused serious health issues in both humans and animals. Microarray technology is an advanced technique suitable for the analysis of chemical contaminates. In particular, immuno-microarray approach is one of the most promising methods for chemical contaminants analysis. The use of microarrays for the analysis of chemical contaminants is the subject of this review. Fabrication strategies and detection methods for chemical contaminants are discussed in detail. Application to the analysis of mycotoxins, biotoxins, pesticide residues, and pharmaceutical residues is also described. Finally, future challenges and opportunities are discussed.

  16. Chemical hazards analysis of resilient flooring for healthcare.

    Science.gov (United States)

    Lent, Tom; Silas, Julie; Vallette, Jim

    2010-01-01

    This article addresses resilient flooring, evaluating the potential health effects of vinyl flooring and the leading alternatives-synthetic rubber, polyolefin, and linoleum-currently used in the healthcare marketplace. The study inventories chemicals incorporated as components of each of the four material types or involved in their life cycle as feedstocks, intermediary chemicals, or emissions. It then characterizes those chemicals using a chemical hazard-based framework that addresses persistence and bioaccumulation, human toxicity, and human exposures.

  17. Analysis of radiation and chemical factors which define the ecological situation of environment

    International Nuclear Information System (INIS)

    Trofimenko, A.P.

    1996-01-01

    A new method of large information set statistical analysis is proposed. It permits to define the main directions of work in a given field in the world or in a particular country, to find the most important investigated problems and to evaluate the role each of them quantitatively, as well as to study the dynamics of work development in time, the methods of research used, the centres in which this research is mostly developed, authors of publications etc. Statistical analysis may be supplemented with subject analysis of selected publications. Main factors which influence on different environment components and on public health are presented as an example of this method use, and the role of radiation and chemical factors is evaluated. 18 refs., 6 tab

  18. Thermodynamic analysis of a directly heated oxyfuel supercritical power system

    International Nuclear Information System (INIS)

    Chowdhury, A.S.M. Arifur; Bugarin, Luz; Badhan, Antara; Choudhuri, Ahsan; Love, Norman

    2016-01-01

    Highlights: • A thermodynamic analysis of a supercritical power cycle is presented. • The supercritical power cycle is modeled using ASPEN HYSYS®. • A liquid methane and oxygen feed system is more efficient than a gaseous system. • CO_2 recirculated in gas form is 10.6% more efficient than when in liquid form. • Commercially available technologies permit liquid feed system delivery. - Abstract: Directly heated supercritical oxy-fuel gas turbines have potential to provide a higher thermal efficiency and lower pollutant emissions compared to current gas turbine systems. Motivated by the advantages of an oxyfuel-based directly heated supercritical power system, this paper presents an analysis of different operating conditions using ASPEN HYSYS®. This study first investigates the efficiency of gaseous or liquid methane and oxygen feed systems. T-s and P-v diagrams are generated and compared to each other to determine which is more efficient. The analysis revealed that the entropy generated during the combustion process for a liquid feed system is approximately three times higher than when methane and oxygen are compressed in gaseous form and delivered to the combustor and burned. To mitigate the high temperatures (3300 K) of the methane and oxygen combustion reaction, carbon dioxide is recirculated. For this portion of the system, the use of gaseous and liquid carbon dioxide recirculation loops and their corresponding efficiencies are determined. The investigation shows that the system yielded a higher net efficiency of 55.1% when gaseous carbon dioxide is recirculated as a diluent with liquid methane and oxygen delivery to the combustor.

  19. Directed Evolution Strategies for Enantiocomplementary Haloalkane Dehalogenases : From Chemical Waste to Enantiopure Building Blocks

    NARCIS (Netherlands)

    van Leeuwen, Jan G. E.; Wijma, Hein J.; Floor, Robert J.; van der Laan, Jan-Metske; Janssen, Dick B.

    2012-01-01

    We used directed evolution to obtain enantiocomplementary haloalkane dehalogenase variants that convert the toxic waste compound 1,2,3-trichloropropane (TCP) into highly enantioenriched (R)- or (S)-2,3-dichloropropan-1-ol, which can easily be converted into optically active

  20. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred Paul Mark; Badu-Tawiah, Abraham K.; Li, Anyin; Soparawalla, Santosh; Roqan, Iman S.; Cooks, Robert Graham

    2013-01-01

    Characterization of the various petroleum constituents (hydronaphthalenes, thiophenes, alkyl substituted benzenes, pyridines, fluorenes, and polycyclic aromatic hydrocarbons) was achieved under ambient conditions without sample preparation by desorption atmospheric pressure chemical ionization (DAPCI). Conditions were chosen for the DAPCI experiments to control whether ionization was by proton or electron transfer. The protonated molecule [M+H]+ and the hydride abstracted [MH]+ form were observed when using an inert gas, typically nitrogen, to direct a lightly ionized plasma generated by corona discharge onto the sample surface in air. The abundant water cluster ions generated in this experiment react with condensed-phase functionalized hydrocarbon model compounds and their mixtures at or near the sample surface. On the other hand, when naphthalene was doped into the DAPCI gas stream, its radical cation served as a charge exchange reagent, yielding molecular radical cations (M+) of the hydrocarbons. This mode of sample ionization provided mass spectra with better signal/noise ratios and without unwanted side-products. It also extended the applicability of DAPCI to petroleum constituents which could not be analyzed through proton transfer (e.g., higher molecular PAHs such as chrysene). The thermochemistry governing the individual ionization processes is discussed and a desorption/ionization mechanism is inferred. © 2012 Elsevier B.V.

  1. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred Paul Mark

    2013-07-01

    Characterization of the various petroleum constituents (hydronaphthalenes, thiophenes, alkyl substituted benzenes, pyridines, fluorenes, and polycyclic aromatic hydrocarbons) was achieved under ambient conditions without sample preparation by desorption atmospheric pressure chemical ionization (DAPCI). Conditions were chosen for the DAPCI experiments to control whether ionization was by proton or electron transfer. The protonated molecule [M+H]+ and the hydride abstracted [MH]+ form were observed when using an inert gas, typically nitrogen, to direct a lightly ionized plasma generated by corona discharge onto the sample surface in air. The abundant water cluster ions generated in this experiment react with condensed-phase functionalized hydrocarbon model compounds and their mixtures at or near the sample surface. On the other hand, when naphthalene was doped into the DAPCI gas stream, its radical cation served as a charge exchange reagent, yielding molecular radical cations (M+) of the hydrocarbons. This mode of sample ionization provided mass spectra with better signal/noise ratios and without unwanted side-products. It also extended the applicability of DAPCI to petroleum constituents which could not be analyzed through proton transfer (e.g., higher molecular PAHs such as chrysene). The thermochemistry governing the individual ionization processes is discussed and a desorption/ionization mechanism is inferred. © 2012 Elsevier B.V.

  2. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

    Science.gov (United States)

    Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

    2017-04-15

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity

    Science.gov (United States)

    Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-chemical stres...

  4. Rapid quality assessment of Radix Aconiti Preparata using direct analysis in real time mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Hongbin; Wang Chunyan; Qi Yao [Changchun Center of Mass Spectrometry and Chemical Biology Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Song Fengrui, E-mail: songfr@ciac.jl.cn [Changchun Center of Mass Spectrometry and Chemical Biology Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Liu Zhiqiang; Liu Shuying [Changchun Center of Mass Spectrometry and Chemical Biology Laboratory, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-11-08

    Highlights: Black-Right-Pointing-Pointer DART MS combined with PCA and HCA was used to rapidly identify markers of Radix Aconiti. Black-Right-Pointing-Pointer The DART MS behavior of six aconitine-type alkaloids was investigated. Black-Right-Pointing-Pointer Chemical markers were recognized between the qualified and unqualified samples. Black-Right-Pointing-Pointer DART MS was shown to be an effective tool for quality control of Radix Aconiti Preparata. - Abstract: This study presents a novel and rapid method to identify chemical markers for the quality control of Radix Aconiti Preparata, a world widely used traditional herbal medicine. In the method, the samples with a fast extraction procedure were analyzed using direct analysis in real time mass spectrometry (DART MS) combined with multivariate data analysis. At present, the quality assessment approach of Radix Aconiti Preparata was based on the two processing methods recorded in Chinese Pharmacopoeia for the purpose of reducing the toxicity of Radix Aconiti and ensuring its clinical therapeutic efficacy. In order to ensure the safety and effectivity in clinical use, the processing degree of Radix Aconiti should be well controlled and assessed. In the paper, hierarchical cluster analysis and principal component analysis were performed to evaluate the DART MS data of Radix Aconiti Preparata samples in different processing times. The results showed that the well processed Radix Aconiti Preparata, unqualified processed and the raw Radix Aconiti could be clustered reasonably corresponding to their constituents. The loading plot shows that the main chemical markers having the most influence on the discrimination amongst the qualified and unqualified samples were mainly some monoester diterpenoid aconitines and diester diterpenoid aconitines, i.e. benzoylmesaconine, hypaconitine, mesaconitine, neoline, benzoylhypaconine, benzoylaconine, fuziline, aconitine and 10-OH-mesaconitine. The established DART MS approach in

  5. Rapid quality assessment of Radix Aconiti Preparata using direct analysis in real time mass spectrometry

    International Nuclear Information System (INIS)

    Zhu Hongbin; Wang Chunyan; Qi Yao; Song Fengrui; Liu Zhiqiang; Liu Shuying

    2012-01-01

    Highlights: ► DART MS combined with PCA and HCA was used to rapidly identify markers of Radix Aconiti. ► The DART MS behavior of six aconitine-type alkaloids was investigated. ► Chemical markers were recognized between the qualified and unqualified samples. ► DART MS was shown to be an effective tool for quality control of Radix Aconiti Preparata. - Abstract: This study presents a novel and rapid method to identify chemical markers for the quality control of Radix Aconiti Preparata, a world widely used traditional herbal medicine. In the method, the samples with a fast extraction procedure were analyzed using direct analysis in real time mass spectrometry (DART MS) combined with multivariate data analysis. At present, the quality assessment approach of Radix Aconiti Preparata was based on the two processing methods recorded in Chinese Pharmacopoeia for the purpose of reducing the toxicity of Radix Aconiti and ensuring its clinical therapeutic efficacy. In order to ensure the safety and effectivity in clinical use, the processing degree of Radix Aconiti should be well controlled and assessed. In the paper, hierarchical cluster analysis and principal component analysis were performed to evaluate the DART MS data of Radix Aconiti Preparata samples in different processing times. The results showed that the well processed Radix Aconiti Preparata, unqualified processed and the raw Radix Aconiti could be clustered reasonably corresponding to their constituents. The loading plot shows that the main chemical markers having the most influence on the discrimination amongst the qualified and unqualified samples were mainly some monoester diterpenoid aconitines and diester diterpenoid aconitines, i.e. benzoylmesaconine, hypaconitine, mesaconitine, neoline, benzoylhypaconine, benzoylaconine, fuziline, aconitine and 10-OH-mesaconitine. The established DART MS approach in combination with multivariate data analysis provides a very flexible and reliable method for quality

  6. Uniformity analysis for a direct-drive laser fusion reactor

    International Nuclear Information System (INIS)

    Lund, L.D.; Skupsky, S.; Goldman, L.M.

    1983-01-01

    We show the results of an analysis of the uniformity for a direct-drive reactor using 20, 32, 60, or 96 beams. Several of these options achieve less than the 1% nonuniformity that is required. These options are considered for the cases where the solid angle fraction of the beam ports is 2% and 8%. The analysis is facilitated by separating the contributions due to the geometrical effects related to the number and orientation of the beams from those due to the spatial profile of the individual beams. Emphasis is placed on the wavelength of the nonuniformities, as the shorter wavelength nonuniformities are more easily smoothed by thermal conduction within the target. The analysis demonstrates that the longer wavelengths can be minimized by suitable choices of geometry and by maintaining beam balance, whereas the shorter wavelength nonuniformities can be reduced by optimizing parameters such as the focal position and the spatial intensity profile of each beam. The tolerances required for beam-to-beam energy balance will be discussed

  7. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction.

    Science.gov (United States)

    Zhu, Hongying; Huang, Guangming

    2015-03-31

    In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m(-3), ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Chemical composition dispersion in bi-metallic nanoparticles: semi-automated analysis using HAADF-STEM

    International Nuclear Information System (INIS)

    Epicier, T.; Sato, K.; Tournus, F.; Konno, T.

    2012-01-01

    We present a method using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) to determine the chemical composition of bi-metallic nanoparticles. This method, which can be applied in a semi-automated way, allows large scale analysis with a statistical number of particles (several hundreds) in a short time. Once a calibration curve has been obtained, e.g., using energy-dispersive X-ray spectroscopy (EDX) measurements on a few particles, the HAADF integrated intensity of each particle can indeed be directly related to its chemical composition. After a theoretical description, this approach is applied to the case of iron–palladium nanoparticles (expected to be nearly stoichiometric) with a mean size of 8.3 nm. It will be shown that an accurate chemical composition histogram is obtained, i.e., the Fe content has been determined to be 49.0 at.% with a dispersion of 10.4 %. HAADF-STEM analysis represents a powerful alternative to fastidious single particle EDX measurements, for the compositional dispersion in alloy nanoparticles.

  9. Instrumental neutron activation analysis, a valuable link in chemical metrology

    International Nuclear Information System (INIS)

    Zeisler, R.; Lindstrom, R.M.; Greenberg, R.R.

    2002-01-01

    Instrumental neutron activation analysis (INAA) is sufficiently versatile to establish a direct link to the amount of substance determined. The inherent quality parameters of INAA, such as being virtually free of blank, having fully accountable effects of matrix and physical form, and operating over a huge range of amounts, allows the comparison of a mole (or its fraction) of a pure element with the amount of substance in the sample analyzed with the same direct relationship as a beam balance provides. Indeed, varieties of this approach are in common use in INAA in the comparator methods of quantitation. To eliminate possible perturbations of the traceability chain as they may occur in common INAA practice, experimental measurements have been set up that only involve the fraction of a mole of the element(s) of interest in form of the pure element, compound or certified standard and the unknown sample. This principle has been used in INAA measurements for certification value assignment of high temperature alloy SRMs. To further demonstrate the performance parameters of INAA, we selected the determination of chromium in SRM 1152a Stainless Steel by direct non-destructive comparison with the pure metal in form of crystalline chromium. The measurements were validated with weighed aliquots of SRM 3112a dried on filter paper pellets. The experimental results do not show deviations beyond the uncertainties of the SRMs (≤ 0.2 % relative), and the assessment of the uncertainty budget indicates that expanded uncertainties of ≤ 0.3 % are achievable. The measurements demonstrate that INAA can meet the CCQM definition of a primary ratio method of analysis

  10. Direct aerosol chemical composition measurements to evaluate the physicochemical differences between controlled sea spray aerosol generation schemes

    Directory of Open Access Journals (Sweden)

    D. B. Collins

    2014-11-01

    Full Text Available Controlled laboratory studies of the physical and chemical properties of sea spray aerosol (SSA must be under-pinned by a physically and chemically accurate representation of the bubble-mediated production of nascent SSA particles. Bubble bursting is sensitive to the physico-chemical properties of seawater. For a sample of seawater, any important differences in the SSA production mechanism are projected into the composition of the aerosol particles produced. Using direct chemical measurements of SSA at the single-particle level, this study presents an intercomparison of three laboratory-based, bubble-mediated SSA production schemes: gas forced through submerged sintered glass filters ("frits", a pulsed plunging-waterfall apparatus, and breaking waves in a wave channel filled with natural seawater. The size-resolved chemical composition of SSA particles produced by breaking waves is more similar to particles produced by the plunging waterfall than those produced by sintered glass filters. Aerosol generated by disintegrating foam produced by sintered glass filters contained a larger fraction of organic-enriched particles and a different size-resolved elemental composition, especially in the 0.8–2 μm dry diameter range. Interestingly, chemical differences between the methods only emerged when the particles were chemically analyzed at the single-particle level as a function of size; averaging the elemental composition of all particles across all sizes masked the differences between the SSA samples. When dried, SSA generated by the sintered glass filters had the highest fraction of particles with spherical morphology compared to the more cubic structure expected for pure NaCl particles produced when the particle contains relatively little organic carbon. In addition to an intercomparison of three SSA production methods, the role of the episodic or "pulsed" nature of the waterfall method on SSA composition was under-taken. In organic

  11. COLLABORATIVE TRIAL AND QUALITY CONTROL IN CHEMICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Narsito Narsito

    2010-06-01

    Full Text Available Abstract                                                             This paper deals with some practical problems related to the quality of analytical chemical data usually met in practice. Special attention is given to the topic of quality control in analytical chemistry, since analytical data is one of the primary information from which some important scientifically based decision are to be made. The present paper starts with brief description on some fundamental aspects associated with quality of analytical data, such as sources of variation of analytical data, criteria for quality of analytical method, quality assurance in chemical analysis. The assessment of quality parameter for analytical method like the use of standard materials as well as standard methods is given. Concerning with the quality control of analytical data, the use of several techniques, such as control samples and control charts, in monitoring analytical data in quality control program are described qualitatively.  In the final part of this paper, some important remarks for the preparation of collaborative trials, including the evaluation of accuracy and reproducibility of analytical method are also given Keywords: collaborative trials, quality control, analytical data Abstract                                                             This paper deals with some practical problems related to the quality of analytical chemical data usually met in practice. Special attention is given to the topic of quality control in analytical chemistry, since analytical data is one of the primary information from which some important scientifically based decision are to be made. The present paper starts with brief description on some fundamental aspects associated with quality of analytical data, such as sources of variation of analytical data, criteria for quality of

  12. Process Equipment Failure Mode Analysis in a Chemical Industry

    Directory of Open Access Journals (Sweden)

    J. Nasl Seraji

    2008-04-01

    Full Text Available Background and aims   Prevention of potential accidents and safety promotion in chemical processes requires systematic safety management in them. The main objective of this study was analysis of important process equipment components failure modes and effects in H2S and CO2  isolation from extracted natural gas process.   Methods   This study was done in sweetening unit of an Iranian gas refinery. Failure Mode and Effect Analysis (FMEA used for identification of process equipments failures.   Results   Totally 30 failures identified and evaluated using FMEA. P-1 blower's blade breaking and sour gas pressure control valve bearing tight moving had maximum risk Priority number (RPN, P-1 body corrosion and increasing plug lower side angle of reach DEAlevel control valve  in tower - 1 were minimum calculated RPN.   Conclusion   By providing a reliable documentation system for equipment failures and  incidents recording, maintaining of basic information for later safety assessments would be  possible. Also, the probability of failures and effects could be minimized by conducting preventive maintenance.

  13. Spectral Analysis by XANES Reveals that GPNMB Influences the Chemical Composition of Intact Melanosomes

    Energy Technology Data Exchange (ETDEWEB)

    T Haraszti; C Trantow; A Hedberg-Buenz; M Grunze; M Anderson

    2011-12-31

    GPNMB is a unique melanosomal protein. Unlike many melanosomal proteins, GPNMB has not been associated with any forms of albinism, and it is unclear whether GPNMB has any direct influence on melanosomes. Here, melanosomes from congenic strains of C57BL/6J mice mutant for Gpnmb are compared to strain-matched controls using standard transmission electron microscopy and synchrotron-based X-ray absorption near-edge structure analysis (XANES). Whereas electron microscopy did not detect any ultrastructural changes in melanosomes lacking functional GPNMB, XANES uncovered multiple spectral phenotypes. These results directly demonstrate that GPNMB influences the chemical composition of melanosomes and more broadly illustrate the potential for using genetic approaches in combination with nano-imaging technologies to study organelle biology.

  14. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  15. NOx Direct Decomposition: Potentially Enhanced Thermodynamics and Kinetics on Chemically Modified Ferroelectric Surfaces

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2014-03-01

    NOx are regulated pollutants produced during automotive combustion. As part of an effort to design catalysts for NOx decomposition that operate in oxygen rich environment and permit greater fuel efficiency, we study chemistry of NOx on (001) ferroelectric surfaces. Changing the polarization at such surfaces modifies electronic properties and leads to switchable surface chemistry. Using first principles theory, our previous work has shown that addition of catalytic RuO2 monolayer on ferroelectric PbTiO3 surface makes direct decomposition of NO thermodynamically favorable for one polarization. Furthermore, the usual problem of blockage of catalytic sites by strong oxygen binding is overcome by flipping polarization that helps desorb the oxygen. We describe a thermodynamic cycle for direct NO decomposition followed by desorption of N2 and O2. We provide energy barriers and transition states for key steps of the cycle as well as describing their dependence on polarization direction. We end by pointing out how a switchable order parameter of substrate,in this case ferroelectric polarization, allows us to break away from some standard compromises for catalyst design(e.g. the Sabatier principle). This enlarges the set of potentially catalytic metals. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  16. ANALYSIS OF A DIRECT SELLING NETWORK FOR AGRIFOOD PRODUCTS

    Directory of Open Access Journals (Sweden)

    Placido Rapisarda

    2015-03-01

    Full Text Available Sicily has become a food and wine area of great interest. However, conflicts within the supply chains have caused the selling process to become long and complex to the disadvantage of farmers, thereby leading to an information asymmetry between producers and consumers.In order to meet the new needs of the agrifood sector, we developed a theoretical model of organized direct selling that goes beyond regional boundaries, which is an alternative model to farmers’ markets and that helps to promote the creation of a network among the operators of Sicilian agrifood supply chains. The aims of this study was to verify the potential of the proposed theoretical model based on a SWOT analysis, which was achieved by collecting data from interviews with the producers involved in the Sicilian agrifood supply chains, and with the main stakeholders involved.

  17. Flow Injection Analysis and Liquid Chromatography for Multifunctional Chemical Analysis (MCA) Systems

    Science.gov (United States)

    Mayo, Ana V.; Loegel, Thomas N.; Bretz, Stacey Lowery; Danielson, Neil D.

    2013-01-01

    The large class sizes of first-year chemistry labs makes it challenging to provide students with hands-on access to instrumentation because the number of students typically far exceeds the number of research-grade instruments available to collect data. Multifunctional chemical analysis (MCA) systems provide a viable alternative for large-scale…

  18. Elucidating Direct Photolysis Mechanisms of Different Dissociation Species of Norfloxacin in Water and Mg2+ Effects by Quantum Chemical Calculations.

    Science.gov (United States)

    Wang, Se; Wang, Zhuang

    2017-11-11

    The study of pollution due to combined antibiotics and metals is urgently needed. Photochemical processes are an important transformation pathway for antibiotics in the environment. The mechanisms underlying the effects of metal-ion complexation on the aquatic photochemical transformation of antibiotics in different dissociation forms are crucial problems in science, and beg solutions. Herein, we investigated the mechanisms of direct photolysis of norfloxacin (NOR) in different dissociation forms in water and metal ion Mg 2+ effects using quantum chemical calculations. Results show that different dissociation forms of NOR had different maximum electronic absorbance wavelengths (NOR 2+ direct photolysis pathways were de-ethylation (N7-C8 bond cleavage) and decarboxylation (C2-C5 bond cleavage). Furthermore, the presence of Mg 2+ changed the order of the wavelength at maximum electronic absorbance (NOR⁺-Mg 2+ direct photolysis of NOR⁰, NOR⁺, and NOR 2+ . The calculated TS results indicated that the presence of Mg 2+ increased E a for most direct photolysis pathways of NOR, while it decreased E a for some direct photolysis pathways such as the loss of the piperazine ring and the damage of the piperazine ring of NOR⁰ and the defluorination of NOR⁺.

  19. Review on mechanism of directly fabricating wafer-scale graphene on dielectric substrates by chemical vapor deposition

    Science.gov (United States)

    Ning, Jing; Wang, Dong; Chai, Yang; Feng, Xin; Mu, Meishan; Guo, Lixin; Zhang, Jincheng; Hao, Yue

    2017-07-01

    To date, chemical vapor deposition on transition metal catalysts is a potential way to achieve low cost, high quality and uniform wafer-scale graphene. However, the removal and transfer process of the annoying catalytic metals underneath can bring large amounts of uncertain factors causing the performance deterioration of graphene, such as the pollution of surface polymeric residues, unmentioned doping and structural damages. Thus, to develop a technique of directly fabricating graphene on dielectric substrates is quite meaningful. In this review, we will present specific methods of catalyst- or transfer-free techniques for graphene growth and discuss the diversity of growth mechanisms.

  20. Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Fa-Kuei Tung

    2009-01-01

    Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

  1. Defect-Free Graphene Synthesized Directly at 150 °C via Chemical Vapor Deposition with No Transfer.

    Science.gov (United States)

    Park, Byeong-Ju; Choi, Jin-Seok; Eom, Ji-Ho; Ha, Hyunwoo; Kim, Hyun You; Lee, Seonhee; Shin, Hyunjung; Yoon, Soon-Gil

    2018-02-27

    Direct graphene synthesis on substrates via chemical vapor deposition (CVD) is an attractive approach for manufacturing flexible electronic devices. The temperature for graphene synthesis must be below ∼200 °C to prevent substrate deformation while fabricating flexible devices on plastic substrates. Herein, we report a process whereby defect-free graphene is directly synthesized on a variety of substrates via the introduction of an ultrathin Ti catalytic layer, due to the strong affinity of Ti to carbon. Ti with a thickness of 10 nm was naturally oxidized by exposure to air before and after the graphene synthesis, and the various functions of neither the substrates nor the graphene were influenced. This report offers experimental evidence of high-quality graphene synthesis on Ti-coated substrates at 150 °C via CVD. The proposed methodology was applied to the fabrication of flexible and transparent thin-film capacitors with top electrodes of high-quality graphene.

  2. Directed self-assembly of nanogold using a chemically modified nanopatterned surface

    Science.gov (United States)

    Nidetz, Robert; Kim, Jinsang

    2012-02-01

    Electron-beam lithography (EBL) was used to define an aminosilane nanopatterned surface in order to electrostatically self-assemble gold nanoparticles (Au NPs). The chemically modified nanopatterned surfaces were immersed into a Au NP solution to allow the Au NPs to self-assemble. Equilibrium self-assembly was achieved in only 20 min. The number of Au NPs that self-assembled on an aminosilane dot was controlled by manipulating the diameters of both the Au NPs and the dots. Adding salt to the Au NP solution enabled the Au NPs to self-assemble in greater numbers on the same sized dot. However, the preparation of the Au NP solution containing salt was sensitive to spikes in the salt concentration. These spikes led to aggregation of the Au NPs and non-specific deposition of Au NPs on the substrate. The Au NP patterned surfaces were immersed in a sodium hydroxide solution in order to lift-off the patterned Au NPs, but no lift-off was observed without adequate physical agitation. The van der Waals forces are too strong to allow for lift-off despite the absence of electrostatic forces.

  3. Directed self-assembly of nanogold using a chemically modified nanopatterned surface

    International Nuclear Information System (INIS)

    Nidetz, Robert; Kim, Jinsang

    2012-01-01

    Electron-beam lithography (EBL) was used to define an aminosilane nanopatterned surface in order to electrostatically self-assemble gold nanoparticles (Au NPs). The chemically modified nanopatterned surfaces were immersed into a Au NP solution to allow the Au NPs to self-assemble. Equilibrium self-assembly was achieved in only 20 min. The number of Au NPs that self-assembled on an aminosilane dot was controlled by manipulating the diameters of both the Au NPs and the dots. Adding salt to the Au NP solution enabled the Au NPs to self-assemble in greater numbers on the same sized dot. However, the preparation of the Au NP solution containing salt was sensitive to spikes in the salt concentration. These spikes led to aggregation of the Au NPs and non-specific deposition of Au NPs on the substrate. The Au NP patterned surfaces were immersed in a sodium hydroxide solution in order to lift-off the patterned Au NPs, but no lift-off was observed without adequate physical agitation. The van der Waals forces are too strong to allow for lift-off despite the absence of electrostatic forces. (paper)

  4. Improving the accuracy of effect-directed analysis: the role of bioavailability.

    Science.gov (United States)

    You, Jing; Li, Huizhen

    2017-12-13

    Aquatic ecosystems have been suffering from contamination by multiple stressors. Traditional chemical-based risk assessment usually fails to explain the toxicity contributions from contaminants that are not regularly monitored or that have an unknown identity. Diagnosing the causes of noted adverse outcomes in the environment is of great importance in ecological risk assessment and in this regard effect-directed analysis (EDA) has been designed to fulfill this purpose. The EDA approach is now increasingly used in aquatic risk assessment owing to its specialty in achieving effect-directed nontarget analysis; however, a lack of environmental relevance makes conventional EDA less favorable. In particular, ignoring the bioavailability in EDA may cause a biased and even erroneous identification of causative toxicants in a mixture. Taking bioavailability into consideration is therefore of great importance to improve the accuracy of EDA diagnosis. The present article reviews the current status and applications of EDA practices that incorporate bioavailability. The use of biological samples is the most obvious way to include bioavailability into EDA applications, but its development is limited due to the small sample size and lack of evidence for metabolizable compounds. Bioavailability/bioaccessibility-based extraction (bioaccessibility-directed and partitioning-based extraction) and passive-dosing techniques are recommended to be used to integrate bioavailability into EDA diagnosis in abiotic samples. Lastly, the future perspectives of expanding and standardizing the use of biological samples and bioavailability-based techniques in EDA are discussed.

  5. Direction-Dependence Analysis: A Confirmatory Approach for Testing Directional Theories

    Science.gov (United States)

    Wiedermann, Wolfgang; von Eye, Alexander

    2015-01-01

    The concept of direction dependence has attracted growing attention due to its potential to help decide which of two competing linear regression models (X ? Y or Y ? X) is more likely to reflect the correct causal flow. Several tests have been proposed to evaluate hypotheses compatible with direction dependence. In this issue, Thoemmes (2015)…

  6. Microplasmas for chemical analysis: analytical tools or research toys?

    International Nuclear Information System (INIS)

    Karanassios, Vassili

    2004-01-01

    An overview of the activities of the research groups that have been involved in fabrication, development and characterization of microplasmas for chemical analysis over the last few years is presented. Microplasmas covered include: miniature inductively coupled plasmas (ICPs); capacitively coupled plasmas (CCPs); microwave-induced plasmas (MIPs); a dielectric barrier discharge (DBD); microhollow cathode discharge (MCHD) or microstructure electrode (MSE) discharges, other microglow discharges (such as those formed between 'liquid' electrodes); microplasmas formed in micrometer-diameter capillary tubes for gas chromatography (GC) or high-performance liquid chromatography (HPLC) applications, and a stabilized capacitive plasma (SCP) for GC applications. Sample introduction into microplasmas, in particular, into a microplasma device (MPD), battery operation of a MPD and of a mini- in-torch vaporization (ITV) microsample introduction system for MPDs, and questions of microplasma portability for use on site (e.g., in the field) are also briefly addressed using examples of current research. To emphasize the significance of sample introduction into microplasmas, some previously unpublished results from the author's laboratory have also been included. And an overall assessment of the state-of-the-art of analytical microplasma research is provided

  7. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  8. An ab initio chemical reaction model for the direct simulation Monte Carlo study of non-equilibrium nitrogen flows.

    Science.gov (United States)

    Mankodi, T K; Bhandarkar, U V; Puranik, B P

    2017-08-28

    A new ab initio based chemical model for a Direct Simulation Monte Carlo (DSMC) study suitable for simulating rarefied flows with a high degree of non-equilibrium is presented. To this end, Collision Induced Dissociation (CID) cross sections for N 2 +N 2 →N 2 +2N are calculated and published using a global complete active space self-consistent field-complete active space second order perturbation theory N 4 potential energy surface and quasi-classical trajectory algorithm for high energy collisions (up to 30 eV). CID cross sections are calculated for only a selected set of ro-vibrational combinations of the two nitrogen molecules, and a fitting scheme based on spectroscopic weights is presented to interpolate the CID cross section for all possible ro-vibrational combinations. The new chemical model is validated by calculating equilibrium reaction rate coefficients that can be compared well with existing shock tube and computational results. High-enthalpy hypersonic nitrogen flows around a cylinder in the transition flow regime are simulated using DSMC to compare the predictions of the current ab initio based chemical model with the prevailing phenomenological model (the total collision energy model). The differences in the predictions are discussed.

  9. Four Chemical Trends Will Shape the Next Decade's Directions in Perfluoroalkyl and Polyfluoroalkyl Substances Research

    Directory of Open Access Journals (Sweden)

    Matthias Kotthoff

    2018-04-01

    Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern.Increase in structural diversity of existing PFAS molecules: Introduction of e.g., hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules.Unknown “Dark Matter”: The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown.These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.

  10. Similarity Analysis of Cable Insulations by Chemical Test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seog [Central Research Institute of Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2013-10-15

    As result of this experiment, it was found that FT-IR test for material composition, TGA test for aging trend are applicable for similarity analysis of cable materials. OIT is recommended as option if TGA doesn't show good trend. Qualification of new insulation by EQ report of old insulation should be based on higher activation energy of new insulation than that of old one in the consideration of conservatism. In old nuclear power plant, it is easy to find black cable which has no marking of cable information such as manufacturer, material name and voltage. If a type test is required for qualification of these cables, how could I select representative cable? How could I determine the similarity of these cables? If manufacturer has qualified a cable for nuclear power plant more than a decade ago and composition of cable material is changed with similar one, is it acceptable to use the old EQ report for recently manufactured cable? It is well known to use FT-IR method to determine the similarity of cable materials. Infrared ray is easy tool to compare compositions of each material. But, it is not proper to compare aging trend of these materials. Study for similarity analysis of cable insulation by chemical test is described herein. To study a similarity evaluation method for polymer materials, FT-IR, TGA and OIT tests were performed for two cable insulation(old and new) which were supplied from same manufacturer. FT-IR shows good result to compare material compositions while TGA and OIT show good result to compare aging character of materials.

  11. Quantum chemical calculations in the structural analysis of phloretin

    Science.gov (United States)

    Gómez-Zavaglia, Andrea

    2009-07-01

    In this work, a conformational search on the molecule of phloretin [2',4',6'-Trihydroxy-3-(4-hydroxyphenyl)-propiophenone] has been performed. The molecule of phloretin has eight dihedral angles, four of them taking part in the carbon backbone and the other four, related with the orientation of the hydroxyl groups. A systematic search involving a random variation of the dihedral angles has been used to generate input structures for the quantum chemical calculations. Calculations at the DFT(B3LYP)/6-311++G(d,p) level of theory permitted the identification of 58 local minima belonging to the C 1 symmetry point group. The molecular structures of the conformers have been analyzed using hierarchical cluster analysis. This method allowed us to group conformers according to their similarities, and thus, to correlate the conformers' stability with structural parameters. The dendrogram obtained from the hierarchical cluster analysis depicted two main clusters. Cluster I included all the conformers with relative energies lower than 25 kJ mol -1 and cluster II, the remaining conformers. The possibility of forming intramolecular hydrogen bonds resulted the main factor contributing for the stability. Accordingly, all conformers depicting intramolecular H-bonds belong to cluster I. These conformations are clearly favored when the carbon backbone is as planar as possible. The values of the νC dbnd O and νOH vibrational modes were compared among all the conformers of phloretin. The redshifts associated with intramolecular H-bonds were correlated with the H-bonds distances and energies.

  12. Similarity Analysis of Cable Insulations by Chemical Test

    International Nuclear Information System (INIS)

    Kim, Jong Seog

    2013-01-01

    As result of this experiment, it was found that FT-IR test for material composition, TGA test for aging trend are applicable for similarity analysis of cable materials. OIT is recommended as option if TGA doesn't show good trend. Qualification of new insulation by EQ report of old insulation should be based on higher activation energy of new insulation than that of old one in the consideration of conservatism. In old nuclear power plant, it is easy to find black cable which has no marking of cable information such as manufacturer, material name and voltage. If a type test is required for qualification of these cables, how could I select representative cable? How could I determine the similarity of these cables? If manufacturer has qualified a cable for nuclear power plant more than a decade ago and composition of cable material is changed with similar one, is it acceptable to use the old EQ report for recently manufactured cable? It is well known to use FT-IR method to determine the similarity of cable materials. Infrared ray is easy tool to compare compositions of each material. But, it is not proper to compare aging trend of these materials. Study for similarity analysis of cable insulation by chemical test is described herein. To study a similarity evaluation method for polymer materials, FT-IR, TGA and OIT tests were performed for two cable insulation(old and new) which were supplied from same manufacturer. FT-IR shows good result to compare material compositions while TGA and OIT show good result to compare aging character of materials

  13. Direct determination of Cd and Pb in human urine by GFAAS with deuterium-lamp background correction using different chemical modifiers

    International Nuclear Information System (INIS)

    Husakova, L.; Baoinova, M.; Sramkova, J.; Cernohorsky, T.

    2007-01-01

    Several authors have contributed to the elaboration of methodology for direct determination of Cd and Pb in urine by graphite furnace atomic absorption spectrometry (GFAAS). In the proposed approaches, Zeeman background correction systems were predominantly used, without paying much attention to the selection of an appropriate chemical modifier. However, systematic studies on eleven recommended and less commonly used modifiers have resulted in optimization of atomization conditions, so that accurate analysis also with the use of D 2 -lamp background correction became possible. This was confirmed by comparative measurements using both background correction systems. For determination of Cd in urine, NH 4 F has been selected resulting in the lowest limit of detection (LOD): 0.07 μg L -1 . NH 4 F promotes efficient atomization at low temperatures and suppresses chloride interference effect. Pd + Sr (nitrate) has been selected as the most adequate modifier for determination of Pb. Its presence raised the maximum tolerable pyrolysis temperature up to 1200 o C, which resulted in the maximum reduction of the background signal and the lowest LOD of 1.5 mg L -1 for Pb (10 μL aliquots of dispensed urine). Applying the above modifiers to the analysis of standards and samples, direct aqueous calibration for accurate analysis of diluted and acidified urine samples became possible. Accuracy of the analysis was verified by the use of commercially available quality control reference materials. (authors)

  14. Directional analysis of extreme winds under mixed climate conditions

    CSIR Research Space (South Africa)

    Kruger, A

    2013-07-01

    Full Text Available Directional statistics provide design engineers with the opportunity to realise considerable cost savings, but these are not yet provided for in the South African standard for wind loading. The development of the directional statistics of extreme...

  15. Nonradiological chemical pathway analysis and identification of chemicals of concern for environmental monitoring at the Hanford Site

    International Nuclear Information System (INIS)

    Blanton, M.L.; Cooper, A.T.; Castleton, K.J.

    1995-11-01

    Pacific Northwest's Surface Environmental Surveillance Project (SESP) is an ongoing effort tot design, review, and conducted monitoring on and off the Hanford site. Chemicals of concern that were selected are listed. Using modeled exposure pathways, the offsite cancer incidence and hazard quotient were calculated and a retrospective pathway analysis performed to estimate what onsite concentrations would be required in the soil for each chemical of concern and other detected chemicals that would be required to obtain an estimated offsite human-health risk of 1.0E-06 cancer incidence or 1.0 hazard quotient. This analysis indicates that current nonradiological chemical contamination occurring on the site does not pose a significant offsite human-health risk; the highest cancer incidence to the offsite maximally exposed individual was from arsenic (1.76E-10); the highest hazard quotient was chromium(VI) (1.48E-04). The most sensitive pathways of exposure were surfacewater and aquatic food consumption. Combined total offsite excess cancer incidence was 2.09E-10 and estimated hazard quotient was 2.40E-04. Of the 17 identified chemicals of concern, the SESP does not currently (routinely) monitor arsenic, benzo(a)pyrene, bis(2- ethylhexyl)phthalate (BEHP), and chrysene. Only 3 of the chemicals of concern (arsenic, BEHP, chloroform) could actually occur in onsite soil at concern high enough to cause a 1.0E-06 excess cancer incidence or a 1.0 hazard index for a given offsite exposure pathway. During the retrospective analysis, 20 other chemicals were also evaluated; only vinyl chloride and thallium could reach targeted offsite risk values

  16. Demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation using peroxydisulfate. Progress report SF2-3-MW-35, October--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.; Wang, F.; Krueger, R.; King, K.; Shell, T.; Farmer, J.C.; Adamson, M.

    1996-01-27

    Direct Chemical Oxidation is an emerging ``omnivorous`` waste destruction technique which uses one of the strongest known oxidants (ammonium peroxydisulfate) to convert organic solids or liquids to carbon dioxide and their mineral constituents. The process operates at ambient pressure and at moderate temperatures (80--100 C) where organic destruction is rapid without catalysts. The byproduct (ammonium sulfate) is benign and may be recycled using commercial electrolysis equipment. The authors have constructed and initially tested a bench-scale facility (batch prereactor and plug-flow reactor) which allows treatability tests on any solid or liquid organic waste surrogate, with off-gas analysis by mass spectroscopy. Shake-down tests of the plug flow reactor on model chemical ethylene glycol confirmed earlier predictive models. Pre-reactor tests on water-immiscible substances confirmed destruction of cotton rags (cellulose), kerosene, tributyl phosphate and triethylamine. The process is intended to provide an all-aqueous, ambient pressure destruction technique for difficult materials not suitable or fully accepted for conventional incineration. Such wastes include solid and liquid mixed wastes containing incinerator chars, halogenated and nitrogenated wastes, oils and greases, and chemical or biological warfare agents.

  17. Demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation using peroxydisulfate. Progress report SF2-3-MW-35, October--December 1995

    International Nuclear Information System (INIS)

    Cooper, J.F.; Wang, F.; Krueger, R.; King, K.; Shell, T.; Farmer, J.C.; Adamson, M.

    1996-01-01

    Direct Chemical Oxidation is an emerging ''omnivorous'' waste destruction technique which uses one of the strongest known oxidants (ammonium peroxydisulfate) to convert organic solids or liquids to carbon dioxide and their mineral constituents. The process operates at ambient pressure and at moderate temperatures (80--100 C) where organic destruction is rapid without catalysts. The byproduct (ammonium sulfate) is benign and may be recycled using commercial electrolysis equipment. The authors have constructed and initially tested a bench-scale facility (batch prereactor and plug-flow reactor) which allows treatability tests on any solid or liquid organic waste surrogate, with off-gas analysis by mass spectroscopy. Shake-down tests of the plug flow reactor on model chemical ethylene glycol confirmed earlier predictive models. Pre-reactor tests on water-immiscible substances confirmed destruction of cotton rags (cellulose), kerosene, tributyl phosphate and triethylamine. The process is intended to provide an all-aqueous, ambient pressure destruction technique for difficult materials not suitable or fully accepted for conventional incineration. Such wastes include solid and liquid mixed wastes containing incinerator chars, halogenated and nitrogenated wastes, oils and greases, and chemical or biological warfare agents

  18. Methodology for national risk analysis and prioritization of toxic industrial chemicals.

    Science.gov (United States)

    Taxell, Piia; Engström, Kerstin; Tuovila, Juha; Söderström, Martin; Kiljunen, Harri; Vanninen, Paula; Santonen, Tiina

    2013-01-01

    The identification of chemicals that pose the greatest threat to human health from incidental releases is a cornerstone in public health preparedness for chemical threats. The present study developed and applied a methodology for the risk analysis and prioritization of industrial chemicals to identify the most significant chemicals that pose a threat to public health in Finland. The prioritization criteria included acute and chronic health hazards, physicochemical and environmental hazards, national production and use quantities, the physicochemical properties of the substances, and the history of substance-related incidents. The presented methodology enabled a systematic review and prioritization of industrial chemicals for the purpose of national public health preparedness for chemical incidents.

  19. Self-organized dysprosium-directed alginate hydrogels and its chemical features

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qianmin [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Gao, Jinwei [Institute for Advanced Materials, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006 (China); Peng, Huojun [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangzhou 510006 (China)

    2016-09-15

    Rational use of self-organized materials may contribute in developing new structures and devices in practical technology. Synthetic metallo-supramolecular gels are generally designed with transitional metal-directed process. However, the assembly of both lanthanide and sodium alginate in macromolecular systems would find a new way of utilizing its physical properties. The stimuli-responsive molecule (alginate) could firmly form stable hydrogels upon the encapsulation of dysprosium ions. In addition, the immobilization of YVO{sub 4}: Eu{sup 3+} nanoparticle in the soft matrix has been achieved and it has never been explored in the fabrication of phosphor-incorporated luminescent alginate gels. The key feature of the present soft matter is that its red emission could be switched off in the presence of sodium ascorbate and the results may have a tremendous impact on the extension of photophysical application based on soft nanoscale devices. - Highlights: • Dy{sup 3+} can be used for the gelation of the dissolved alginate. • Lanthanide hydrogels could exhibit red emissions under excitations. • Luminescence could be switched “off” in the presence of sodium ascorbate.

  20. Repeatability, correlation and path analysis of physical and chemical characteristics of peach fruits

    Directory of Open Access Journals (Sweden)

    Rosana Gonçalves Pires Matias

    2014-12-01

    Full Text Available This study aimed to determine the number of measurements necessary to evaluate physical and chemical characteristics of peach fruits, study the relationships between them and their direct and indirect effects on the content of ascorbic acid and total carotenoids. The characteristics skin and pulp color, fruit weight, suture, equatorial and polar diameters, firmness, soluble solids (SS, titratable acidity (TA, SS/TA ratio, ascorbic acid and total carotenoids were evaluated in 39 cultivars of peach and 3 cultivars of nectarine from the orchard of the Universidade Federal de Viçosa. The repeatability coefficient was estimated by ANOVA and CPCOR. Phenotypic correlation coefficients (rf were estimated and, after the multicollinearity diagnostics, they were unfolded to direct and indirect effects of the explanatory variables on the response variable using path analysis. There was agreement on the magnitude of repeatability coefficients obtained by the two methods; however, they varied among the 14 characteristics. The highest correlations were found between FW, SD, ED and PD. Seven fruits are sufficient to evaluate the physical and chemical characteristics of peach with a correlation coefficient of 90%. The characteristics considered in the path diagrams (b* skin, hº skin, b* pulp, hº pulp, ED, PD, FIR, SS, SS/AT and TC are not the main determinants of the ascorbic acid. The yellow hue of the pulp (hº pulp has the potential to be used in indirect selection for total carotenoids.

  1. Advances in directional borehole radar data analysis and visualization

    Science.gov (United States)

    Smith, D.V.G.; Brown, P.J.

    2002-01-01

    The U.S. Geological Survey is developing a directional borehole radar (DBOR) tool for mapping fractures, lithologic changes, and underground utility and void detection. An important part of the development of the DBOR tool is data analysis and visualization, with the aim of making the software graphical user interface (GUI) intuitive and easy to use. The DBOR software system consists of a suite of signal and image processing routines written in Research Systems' Interactive Data Language (IDL). The software also serves as a front-end to many widely accepted Colorado School of Mines Center for Wave Phenomena (CWP) Seismic UNIX (SU) algorithms (Cohen and Stockwell, 2001). Although the SU collection runs natively in a UNIX environment, our system seamlessly emulates a UNIX session within a widely used PC operating system (MicroSoft Windows) using GNU tools (Noer, 1998). Examples are presented of laboratory data acquired with the prototype tool from two different experimental settings. The first experiment imaged plastic pipes in a macro-scale sand tank. The second experiment monitored the progress of an invasion front resulting from oil injection. Finally, challenges to further development and planned future work are discussed.

  2. Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting

    Energy Technology Data Exchange (ETDEWEB)

    Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au [Deakin University, Pigdons Road, Geelong, Victoria, 3216 (Australia); Wood, Kathleen [Australian Nuclear Science and Technology Organisation, Bragg Institute, New South Wales, 2234, Menai (Australia); Taylor, Adam; Hodgson, Peter; Stanford, Nicole [Deakin University, Pigdons Road, Geelong, Victoria, 3216 (Australia)

    2016-02-15

    A high strength low alloy steel composition has been melted and processed by two different routes: simulated direct strip casting and slow cooled ingot casting. The microstructures were examined with scanning and transmission electron microscopy, atom probe tomography and small angle neutron scattering (SANS). The formation of cementite (Fe{sub 3}C), manganese sulphides (MnS) and niobium carbo-nitrides (Nb(C,N)) was investigated in both casting conditions. The sulphides were found to be significantly refined by the higher cooling rate, and developed an average diameter of only 100 nm for the fast cooled sample, and a diameter too large to be measured with SANS in the slow cooled condition (> 1.1 μm). Slow cooling resulted in the development of classical Nb(C,N) precipitation, with an average diameter of 7.2 nm. However, after rapid cooling both the SANS and atom probe tomography data indicated that the Nb was retained in the matrix as a random solid solution. There was also some evidence that O, N and S are also retained in solid solution in levels not found during conventional processing. - Highlights: • The influence of cooling rate on microstructure is investigated in a HSLA steel. • SANS, TEM and APT are used to characterise the sulphides and Nb(C,N) precipitates. • The slow cooling rate result in the formation of Nb(C,N) precipitates. • The fast cooling rate results in a microstructure supersaturated in Nb, C and N. • The sulphides are 100 nm in the fast cooled sample and > 1 μm in the slow cooled one.

  3. Embedded Fragments from U.S. Military Personnel—Chemical Analysis and Potential Health Implications

    Directory of Open Access Journals (Sweden)

    José A. Centeno

    2014-01-01

    Full Text Available Background: The majority of modern war wounds are characterized by high-energy blast injuries containing a wide range of retained foreign materials of a metallic or composite nature. Health effects of retained fragments range from local or systemic toxicities to foreign body reactions or malignancies, and dependent on the chemical composition and corrosiveness of the fragments in vivo. Information obtained by chemical analysis of excised fragments can be used to guide clinical decisions regarding the need for fragment removal, to develop therapeutic interventions, and to better anticipate future medical problems from retained fragment related injuries. In response to this need, a new U.S Department of Defense (DoD directive has been issued requiring characterization of all removed fragments to provide a database of fragment types occurring in combat injuries. Objectives: The objective of this study is to determine the chemical composition of retained embedded fragments removed from injured military personnel, and to relate results to histological findings in tissue adjacent to fragment material. Methods: We describe an approach for the chemical analysis and characterization of retained fragments and adjacent tissues, and include case examples describing fragments containing depleted uranium (DU, tungsten (W, lead (Pb, and non-metal foreign bodies composed of natural and composite materials. Fragments obtained from four patients with penetrating blast wounds to the limbs were studied employing a wide range of chemical and microscopy techniques. Available adjacent tissues from three of the cases were histologically, microscopically, and chemically examined. The physical and compositional properties of the removed foreign material surfaces were examined with energy dispersive x-ray fluorescence spectrometry (EDXRF, scanning electron microscopy (SEM, laser ablation inductively-coupled plasma mass-spectrometry (LA-ICP-MS, and confocal laser Raman

  4. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  5. Meta-Analysis of the Chemical and Non-Chemical Stressors Affecting Childhood Obesity?

    Science.gov (United States)

    Background: Worldwide, approximately 42 million children under the age of 5 years are considered overweight or obese. While much research has focused on individual behaviors impacting obesity, little research has emphasized the complex interactions of numerous chemical and non-ch...

  6. Direct Survival Analysis: a new stock assessment method

    Directory of Open Access Journals (Sweden)

    Eduardo Ferrandis

    2007-03-01

    Full Text Available In this work, a new stock assessment method, Direct Survival Analysis, is proposed and described. The parameter estimation of the Weibull survival model proposed by Ferrandis (2007 is obtained using trawl survey data. This estimation is used to establish a baseline survival function, which is in turn used to estimate the specific survival functions in the different cohorts considered through an adaptation of the separable model of the fishing mortality rates introduced by Pope and Shepherd (1982. It is thus possible to test hypotheses on the evolution of survival during the period studied and to identify trends in recruitment. A link is established between the preceding analysis of trawl survey data and the commercial catch-at-age data that are generally obtained to evaluate the population using analytical models. The estimated baseline survival, with the proposed versions of the stock and catch equations and the adaptation of the Separable Model, may be applied to commercial catch-at-age data. This makes it possible to estimate the survival corresponding to the landing data, the initial size of the cohort and finally, an effective age of first capture, in order to complete the parameter model estimation and consequently the estimation of the whole survival and mortality, along with the reference parameters that are useful for management purposes. Alternatively, this estimation of an effective age of first capture may be obtained by adapting the demographic structure of trawl survey data to that of the commercial fleet through suitable selectivity models of the commercial gears. The complete model provides the evaluation of the stock at any age. The coherence (and hence the mutual “calibration” between the two kinds of information may be analysed and compared with results obtained by other methods, such as virtual population analysis (VPA, in order to improve the diagnosis of the state of exploitation of the population. The model may be

  7. Sampling and chemical analysis of groundwaters from the exploratory boreholes

    International Nuclear Information System (INIS)

    Wittwer, C.

    1986-10-01

    As a part of the Nagra geological investigation programme in northern Switzerland, numerous water samples were taken in the Boettstein, Weiach, Riniken, Schafisheim, Kaisten and Leuggern boreholes to obtain information on the chemistry and residence times of deep groundwaters. This report contains a compilation of hydrochemical data, comments on the individual water sampling actions and an evaluation of sample quality with respect to admixing of drilling fluids. The samples were taken from separate test intervals in the sediments and the crystalline rock. After removal of various types of drilling fluids such as mud as well as fresh water or deionised water during a cleaning phase, the samples were taken at the surface or at depth using pressure vessels. The tracers added to the drilling fluids (uranine, m-TFMBA) as well as the tritium content were used for a quantiative estimation of the content of drilling fluid in the samples (contamination). With a view fo further geochemical modelling, the samples were assessed with reference to the effect of contamination on the results of the chemical analyses. A total of 68 water samples were taken from 53 different intervals: - 27 samples had problem-free cleaning phases and were taken with negligible contamination. - 23 samples were taken under difficult conditions. Problems with hydraulic communication around packers, uncertain origin, inaccuracy as to extent of contamination, presence of cement, possible traces of salt from drilling fluid etc. meant that the analyses could only be used with extreme caution or after additional data-processing. - The analysis results from 18 samples will be disregarded due to significant drilling fluid content or because more reliable data are available for the same test interval. (author)

  8. Understanding Land Use Impacts on Groundwater Quality Using Chemical Analysis

    Science.gov (United States)

    Nitka, A.; Masarik, K.; Masterpole, D.; Johnson, B.; Piette, S.

    2017-12-01

    Chippewa County, in western Wisconsin, has a unique historical set of groundwater quality data. The county conducted extensive groundwater sampling of private wells in 1985 (715 wells) and 2007 (800 wells). In 2016, they collaborated with UW-Extension and UW-Stevens Point to evaluate the current status of groundwater quality in Chippewa County by sampling of as many of the previously studied wells as possible. Nitrate was a primary focus of this groundwater quality inventory. Of the 744 samples collected, 60 were further analyzed for chemical indicators of agricultural and septic waste, two major sources of nitrate contamination. Wells for nitrate source analysis were selected from the 2016 participants based upon certain criteria. Only wells with a Wisconsin Unique Well Number were considered to ensure well construction information was available. Next, an Inverse Distance Weighting tool in ESRI ArcMap was used to assign values categorizing septic density. Two-thirds of the wells were selected in higher density areas and one-third in lower density areas. Equally prioritized was an even distribution of nitrate - N concentrations, with 28 of the wells having nitrate - N concentrations higher than the drinking water standard of 10 mg/L and 32 wells with concentrations between 2 and 10 mg/L. All wells with WUWN and nitrate - N concentrations greater than 20 mg/L were selected. The results of the nitrate source analyses will aid in determining temporal changes and spatial relationships of groundwater quality to soils, geology and land use in Chippewa County.

  9. Association rule mining data for census tract chemical exposure analysis

    Data.gov (United States)

    U.S. Environmental Protection Agency — Chemical concentration, exposure, and health risk data for U.S. census tracts from National Scale Air Toxics Assessment (NATA). This dataset is associated with the...

  10. Microbiological and Physico-chemical Analysis of Compost and its ...

    African Journals Online (AJOL)

    microbial counts, the physico-chemical parameters of compost and to assess the ... showed that application of municipal solid waste ... cattle manure and food wastes (leaves of avocado, .... Organic matter is decomposed and transformed to.

  11. Disclosure of hydraulic fracturing fluid chemical additives: analysis of regulations.

    Science.gov (United States)

    Maule, Alexis L; Makey, Colleen M; Benson, Eugene B; Burrows, Isaac J; Scammell, Madeleine K

    2013-01-01

    Hydraulic fracturing is used to extract natural gas from shale formations. The process involves injecting into the ground fracturing fluids that contain thousands of gallons of chemical additives. Companies are not mandated by federal regulations to disclose the identities or quantities of chemicals used during hydraulic fracturing operations on private or public lands. States have begun to regulate hydraulic fracturing fluids by mandating chemical disclosure. These laws have shortcomings including nondisclosure of proprietary or "trade secret" mixtures, insufficient penalties for reporting inaccurate or incomplete information, and timelines that allow for after-the-fact reporting. These limitations leave lawmakers, regulators, public safety officers, and the public uninformed and ill-prepared to anticipate and respond to possible environmental and human health hazards associated with hydraulic fracturing fluids. We explore hydraulic fracturing exemptions from federal regulations, as well as current and future efforts to mandate chemical disclosure at the federal and state level.

  12. Analysis of very thin organic fibres by means of small spots electron spectroscopy for chemical analysis

    International Nuclear Information System (INIS)

    Daiser, S.M.; Cormia, R.D.; Scharpen, L.

    1985-01-01

    ESCA analysis of very thin organic fibres as small as a few micrometer diameter is now possible using the small spot X-ray capability of the SSX100 ESCA system. The sampling method involves suspending the material in the SSX100 chamber, and illuminating it with a monochromatized X-ray beam of 150-300 μm diameter. From the small spot ESCA spectra one can determine the chemical character of the organic layer and the thickness. (Author)

  13. Process Analysis in Chemical Plant by Means of Radioactive Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, T.; Hamada, K.; Osada, K. [Showa Denko K.K., Tokyo (Japan)

    1967-06-15

    Following the movement of solids and fluids is important in chemical processes to determine mixing efficiency and residence time. Since it is necessary to follow many complex substances such as raw materials, intermediates and reactants in plant investigations, it is often necessary to ascertain whether the behaviour of the radioisotope tracer and the substance to be traced are identical. The most difficult problem is to determine the best method of labelling, a factor which is a substantial key to the success of an experiment. Usually, there are three labelling techniques: radioisotope labelling, pre-.activation of the material and post-activation of the material. This paper deals with practical examples of the double-tracer technique, a combination of conventional radioisotope labelling and post-activation methods by means of activation analysis. In process analysis by means of tracers, a practical measurement method should also be devised and developed for each experiment. Phosphorus-32 and gold (non-radioactive) were used to measure retention time in a carbon-black plant. The radioisotope was pumped into a feed-stock pipe positioned before the reactor and samples were taken from each process of the plant, including the bag filter, mixer and product tank. After sampling from each step of the process, {sup 32}P in a semi-infinite powder sample was measured in situ by beta counting, and the gold was measured by gamma counting after activating the sample in a reactor. The experiment showed that both tracers had the same residence time, which was shorter than expected. Useful data were also obtained from the dispersion pattern of the material flow for future operation controls, including the time required to change from one grade of product to another. Practical tracer techniques to measure mixing characteristics in high-speed gas flows using {sup 85}Kr have been developed. A study of the measurement method was conducted by calculating the differential values of

  14. Chemical analysis of carbonates and carbonate rocks by atomic absorption analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tardon, S

    1981-01-01

    Evaluates methods of determining chemical composition of rocks surrounding black coal seams. Carbonate rock samples were collected in the Ostrava-Karvina coal mines. Sampling methods are described. Determination of the following elements and compounds in carbonate rocks is discussed: calcium, magnesium, iron, manganese, barium, silicon, aluminium, titanium, sodium, potassium, sulfur trioxide, phosphorus pentoxide, water and carbon dioxide. Proportion of compounds insoluble in water in the investigated rocks is also determined. Most of the elements are determined by means of atomic absorption analysis. Phosphorus is also determined by atomic absorption analysis. Other compounds are determined gravimetrically. The described procedure permits weight of a rock sample to be reduced to 0.5 g without reducing analysis accuracy. The results of determining carbonate rock components by X-ray analysis and by chemical analysis are compared. Equipment used for atomic absorption analysis is characterized (the 503 Perkin-Elmer and the CF-4 Optica-Milano spectrophotometers). The analyzed method for determining carbonate rock permits more accurate classification of rocks surrounding coal seams and rock impurities in run-of-mine coal. (22 refs.) (In Czech)

  15. 3D DIRECTIONAL MATHEMATICAL MORPHOLOGY FOR ANALYSIS OF FIBER ORIENTATIONS

    Directory of Open Access Journals (Sweden)

    Hellen Altendorf

    2011-05-01

    Full Text Available In this paper we present algorithms for measuring local characteristics of random fiber systems. The calculation of the local directions and radii is based on directional distance transforms and evaluation of the inertia moments and axes of the resulting extremities of the centralized, directed chords. The method provides continuous results while minimizing the runtime by using few sampled directions. Furthermore several steps of improvement for the computation of orientation and radius information are presented. The algorithms are evaluated using synthetic data and applied to images of realmicrostructures obtained by computer tomography.

  16. High-throughput peptide mass fingerprinting and protein macroarray analysis using chemical printing strategies

    International Nuclear Information System (INIS)

    Sloane, A.J.; Duff, J.L.; Hopwood, F.G.; Wilson, N.L.; Smith, P.E.; Hill, C.J.; Packer, N.H.; Williams, K.L.; Gooley, A.A.; Cole, R.A.; Cooley, P.W.; Wallace, D.B.

    2001-01-01

    We describe a 'chemical printer' that uses piezoelectric pulsing for rapid and accurate microdispensing of picolitre volumes of fluid for proteomic analysis of 'protein macroarrays'. Unlike positive transfer and pin transfer systems, our printer dispenses fluid in a non-contact process that ensures that the fluid source cannot be contaminated by substrate during a printing event. We demonstrate automated delivery of enzyme and matrix solutions for on-membrane protein digestion and subsequent peptide mass fingerprinting (pmf) analysis directly from the membrane surface using matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). This approach bypasses the more commonly used multi-step procedures, thereby permitting a more rapid procedure for protein identification. We also highlight the advantage of printing different chemistries onto an individual protein spot for multiple microscale analyses. This ability is particularly useful when detailed characterisation of rare and valuable sample is required. Using a combination of PNGase F and trypsin we have mapped sites of N-glycosylation using on-membrane digestion strategies. We also demonstrate the ability to print multiple serum samples in a micro-ELISA format and rapidly screen a protein macroarray of human blood plasma for pathogen-derived antigens. We anticipate that the 'chemical printer' will be a major component of proteomic platforms for high-throughput protein identification and characterisation with widespread applications in biomedical and diagnostic discovery

  17. Direct olive oil analysis by mass spectrometry: A comparison of different ambient ionization methods.

    Science.gov (United States)

    Lara-Ortega, Felipe J; Beneito-Cambra, Miriam; Robles-Molina, José; García-Reyes, Juan F; Gilbert-López, Bienvenida; Molina-Díaz, Antonio

    2018-04-01

    Analytical methods based on ambient ionization mass spectrometry (AIMS) combine the classic outstanding performance of mass spectrometry in terms of sensitivity and selectivity along with convenient features related to the lack of sample workup required. In this work, the performance of different mass spectrometry-based methods has been assessed for the direct analyses of virgin olive oil for quality purposes. Two sets of experiments have been setup: (1) direct analysis of untreated olive oil using AIMS methods such as Low-Temperature Plasma Mass Spectrometry (LTP-MS) or paper spray mass spectrometry (PS-MS); or alternatively (2) the use of atmospheric pressure ionization (API) mass spectrometry by direct infusion of a diluted sample through either atmospheric pressure chemical ionization (APCI) or electrospray (ESI) ionization sources. The second strategy involved a minimum sample work-up consisting of a simple olive oil dilution (from 1:10 to 1:1000) with appropriate solvents, which originated critical carry over effects in ESI, making unreliable its use in routine; thus, ESI required the use of a liquid-liquid extraction to shift the measurement towards a specific part of the composition of the edible oil (i.e. polyphenol rich fraction or lipid/fatty acid profile). On the other hand, LTP-MS enabled direct undiluted mass analysis of olive oil. The use of PS-MS provided additional advantages such as an extended ionization coverage/molecular weight range (compared to LTP-MS) and the possibility to increase the ionization efficiency towards nonpolar compounds such as squalene through the formation of Ag + adducts with carbon-carbon double bounds, an attractive feature to discriminate between oils with different degree of unsaturation. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Direct insight into grains formation in Si layers grown on 3C-SiC by chemical vapor deposition

    International Nuclear Information System (INIS)

    Khazaka, Rami; Portail, Marc; Vennéguès, Philippe; Alquier, Daniel; Michaud, Jean François

    2015-01-01

    Graphical abstract: In this contribution, we demonstrated the influence of the 3C-SiC layer on the subsequent growth of Si epilayers. We were able to give a direct evidence that the rotation in the Si epilayer of 90° around the growth direction occurs exactly on the termination of an antiphase boundary in the 3C-SiC layer as shown in the figure above. Thus, increasing the layer thickness of the 3C-SiC leads to a direct improvement of the crystalline quality of the subsequent Si epilayer. (a) Cross-section bright-field TEM image of the Si/3C-SiC layer stack along two 3C-SiC zone axes [1 −1 0] and [1 1 0] (equivalent to [1 −1 1] and [1 1 2] in Si, respectively), (b) dark field image selecting a (2 0 −2) electron diffraction spot indicated by the black circle in the SAED shown as inset, (c) dark field image selecting a (−1 1 −1) electron diffraction spot indicated by the black circle in the SAED shown as inset. The dotted white line in the images show the position of the defect in the 3C-SiC layer. - Abstract: This work presents a structural study of silicon (Si) thin films grown on cubic silicon carbide (3C-SiC) by chemical vapor deposition. The presence of grains rotated by 90° around the growth direction in the Si layer is directly related to the presence of antiphase domains on the 3C-SiC surface. We were able to provide a direct evidence that the 90° rotation of Si grains around the growth direction occurs exactly on the termination of antiphase boundaries (APBs) in 3C-SiC layer. Increasing the 3C-SiC thickness reduces the APBs density on 3C-SiC surface leading to a clear improvement of the uppermost Si film crystal quality. Furthermore, we observed by high resolution plan-view TEM images the presence of hexagonal Si domains limited to few nm in size. These hexagonal Si domains are inclusions in small Si grains enclosed in larger ones rotated by 90°. Finally, we propose a model of grains formation in the Si layer taking into consideration the effect

  19. Direct comparative analysis of conventional and directional freezing for the cryopreservation of whole ovaries

    NARCIS (Netherlands)

    Maffei, S.; Hanenberg, M.; Pennarossa, G.; Roberto V. Silva, J.; Tiziana, A.; Brevini, L.; Pharm, D.; Arav, A.; Gandolfi, F.

    2013-01-01

    INTERVENTION(S): Eighty-one ovaries were randomly assigned to fresh control, conventional freezing (CF), and directional freezing (DF) group. Ovaries of CF and DF groups were perfused via the ovarian artery with Leibovitz L-15 medium, 10% fetal bovine serum, and 1.5 M dimethyl sulfoxide for 5

  20. Investigation of chemical and electrochemical reactions mechanisms in a direct carbon fuel cell using olive wood charcoal as sustainable fuel

    Science.gov (United States)

    Elleuch, Amal; Halouani, Kamel; Li, Yongdan

    2015-05-01

    Direct carbon fuel cell (DCFC) is a high temperature fuel cell using solid carbon as fuel. The use of environmentally friendly carbon material constitutes a promising option for the DCFC future. In this context, this paper focuses on the use of biomass-derived charcoal renewable fuel. A practical investigation of Tunisian olive wood charcoal (OW-C) in planar DCFCs is conducted and good power density (105 mW cm-2) and higher current density (550 mA cm-2) are obtained at 700 °C. Analytical and predictive techniques are performed to explore the relationships between fuel properties and DCFC chemical and electrochemical mechanisms. High carbon content, carbon-oxygen groups and disordered structure, are the key parameters allowing the achieved good performance. Relatively complex chain reactions are predicted to explain the gas evolution within the anode. CO, H2 and CH4 participation in the anodic reaction is proved.

  1. Transient heat transfer in a directly-irradiated solar chemical reactor for the thermal dissociation of ZnO

    International Nuclear Information System (INIS)

    Mueller, R.; Lipinski, W.; Steinfeld, A.

    2008-01-01

    A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates

  2. Ordered self-assembled monolayers terminated with different chemical functional groups direct neural stem cell linage behaviours

    International Nuclear Information System (INIS)

    Yao, Shenglian; Liu, Xi; He, Jin; Wang, Xiumei; Wang, Ying; Cui, Fu-Zhai

    2016-01-01

    Neural stem cells (NSCs) have been a promising candidate for stem cell-based nerve tissue regeneration. Therefore, the design of idea biomaterials that deliver precise regulatory signals to control stem cell fate is currently a crucial issue that depends on a profound understanding of the interactions between NSCs with the surrounding micro-environment. In this work, self-assembled monolayers of alkanethiols on gold with different chemical groups, including hydroxyl (−OH), amino (−NH 2 ), carboxyl (−COOH) and methyl (−CH 3 ), were used as a simple model to study the effects of surface chemistry on NSC fate decisions. Contact angle measurement and x-ray photoelectron spectroscopy (XPS) examination implied that all types of alkanethiols self-assembled on gold into a close-packed phase structure with similar molecular densities. In this study, we evaluated NSC adhesion, migration and differentiation in response to different chemical functional groups cultured under serum-free conditions. Our studies showed that NSCs exhibited certain phenotypes with extreme sensitivity to surface chemical groups. Compared with other functional groups, the SAMs with hydroxyl end-groups provided the best micro-environment in promoting NSC migration and maintaining an undifferentiated or neuronal differentiation state.  −NH 2 surfaces directed neural stem cells into astrocytic lineages, while NSCs on  −COOH and  −CH 3 surfaces had a similar potency to differentiate into three nerve lineages. To further investigate the possible signaling pathway, the gene expression of integrin β1 and β4 were examined. The results indicated that a high expression of β1 integrin would probably have a tight correlation with the expression of nestin, which implied the stemness of NSCs, while β4 integrin seemed to correspond to the differentiated NSCs. The results presented here give useful information for the future design of biomaterials to regulate the preservation

  3. Spatially resolved chemical analysis of cicada wings using laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS).

    Science.gov (United States)

    Román, Jessica K; Walsh, Callee M; Oh, Junho; Dana, Catherine E; Hong, Sungmin; Jo, Kyoo D; Alleyne, Marianne; Miljkovic, Nenad; Cropek, Donald M

    2018-03-01

    Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis. We demonstrate here the applicability of LAESI-IMS for the chemical analysis of thin, desiccated biological samples, specifically Neotibicen pruinosus cicada wings. Positive-ion LAESI-IMS accurate ion-map data was acquired from several wing cells and superimposed onto optical images allowing for compositional comparisons across areas of the wing. Various putative chemical identifications were made indicating the presence of hydrocarbons, lipids/esters, amines/amides, and sulfonated/phosphorylated compounds. With the spatial resolution capability, surprising chemical distribution patterns were observed across the cicada wing, which may assist in correlating trends in surface properties with chemical distribution. Observed ions were either (1) equally dispersed across the wing, (2) more concentrated closer to the body of the insect (proximal end), or (3) more concentrated toward the tip of the wing (distal end). These findings demonstrate LAESI-IMS as a tool for the acquisition of spatially resolved chemical information from fragile, dried insect wings. This LAESI-IMS technique has important implications for the study of functional biomaterials, where understanding the correlation between chemical composition, physical structure, and biological function is critical. Graphical abstract Positive-ion laser-ablation electrospray ionization mass spectrometry coupled with optical imaging provides a powerful tool for the spatially resolved chemical analysis of cicada wings.

  4. Ultrastructural Analysis of Urinary Stones by Microfocus Computed Tomography and Comparison with Chemical Analysis

    Directory of Open Access Journals (Sweden)

    Tolga Karakan

    2016-06-01

    Full Text Available Objective: To investigate the ultra-structure of urinary system stones using micro-focus computed tomography (MCT, which makes non-destructive analysis and to compare with wet chemical analysis. Methods: This study was carried out at the Ankara Train­ing and Research hospital. Renal stones, removed from 30 patients during percutaneous nephrolithotomy (PNL surgery, were included in the study. The stones were blindly evaluated by the specialists with MCT and chemi­cal analysis. Results: The comparison of the stone components be­tween chemical analysis and MCT, showed that the rate of consistence was very low (p0.05. It was also seen that there was no significant relation between its 3D structure being heterogeneous or homogenous. Conclusion: The stone analysis with MCT is a time con­suming and costly method. This method is useful to un­derstand the mechanisms of stone formation and an im­portant guide to develop the future treatment modalities.

  5. Direct determination of cadmium in Orujo spirit samples by electrothermal atomic absorption spectrometry: Comparative study of different chemical modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Vilar Farinas, M. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Barciela Garcia, J. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Garcia Martin, S. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Pena Crecente, R. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Herrero Latorre, C. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain)]. E-mail: cherrero@lugo.usc.es

    2007-05-22

    In this work, several analytical methods are proposed for cadmium determination in Orujo spirit samples using electrothermal atomic absorption spectrometry (ETAAS). Permanent chemical modifiers thermally coated on the platforms inserted in pyrolytic graphite tubes (such as W, Ir, Ru, W-Ir and W-Ru) were comparatively studied in relation to common chemical modifier mixtures [Pd-Mg(NO{sub 3}){sub 2} and (NH{sub 4})H{sub 2}PO{sub 4}-Mg(NO{sub 3}){sub 2}] for cadmium stabilization. Different ETAAS Cd determination methods based on the indicated modifiers have been developed. In each case, pyrolysis and atomization temperatures, atomization shapes, characteristic masses and detection limits as well as other analytical characteristics have been determined. All the assayed modifiers (permanent and conventional) were capable of achieving the appropriate stabilization of the analyte, with the exception of Ru and W-Ru. Moreover, for all developed methods, recoveries (99-102%) and precision (R.S.D. lower than 10%) were acceptable. Taking into account the analytical performance (best detection limit LOD = 0.01 {mu}g L{sup -1}), the ETAAS method based on the use of W as a permanent modifier was selected for further direct Cd determinations in Orujo samples from Galicia (NW Spain). The chosen method was applied in the determination of the Cd content in 38 representative Galician samples. The cadmium concentrations ranged

  6. Energy Effectiveness of Direct UV and UV/H2O2 Treatment of Estrogenic Chemicals in Biologically Treated Sewage

    Directory of Open Access Journals (Sweden)

    Kamilla M. S. Hansen

    2012-01-01

    Full Text Available Continuous exposure of aquatic life to estrogenic chemicals via wastewater treatment plant effluents has in recent years received considerable attention due to the high sensitivity of oviparous animals to disturbances of estrogen-controlled physiology. The removal efficiency by direct UV and the UV/H2O2 treatment was investigated in biologically treated sewage for most of the estrogenic compounds reported in wastewater. The investigated compounds included parabens, industrial phenols, sunscreen chemicals, and steroid estrogens. Treatment experiments were performed in a flow through setup. The effect of different concentrations of H2O2 and different UV doses was investigated for all compounds in an effluent from a biological wastewater treatment plant. Removal effectiveness increased with H2O2 concentration until 60 mg/L. The treatment effectiveness was reported as the electrical energy consumed per unit volume of water treated required for 90% removal of the investigated compound. It was found that the removal of all the compounds was dependent on the UV dose for both treatment methods. The required energy for 90% removal of the compounds was between 28 kWh/m3 (butylparaben and 1.2 kWh/m3 (estrone for the UV treatment. In comparison, the UV/H2O2 treatment required between 8.7 kWh/m3 for bisphenol A and benzophenone-7 and 1.8 kWh/m3 for ethinylestradiol.

  7. Direct determination of cadmium in Orujo spirit samples by electrothermal atomic absorption spectrometry: Comparative study of different chemical modifiers

    International Nuclear Information System (INIS)

    Vilar Farinas, M.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.; Herrero Latorre, C.

    2007-01-01

    In this work, several analytical methods are proposed for cadmium determination in Orujo spirit samples using electrothermal atomic absorption spectrometry (ETAAS). Permanent chemical modifiers thermally coated on the platforms inserted in pyrolytic graphite tubes (such as W, Ir, Ru, W-Ir and W-Ru) were comparatively studied in relation to common chemical modifier mixtures [Pd-Mg(NO 3 ) 2 and (NH 4 )H 2 PO 4 -Mg(NO 3 ) 2 ] for cadmium stabilization. Different ETAAS Cd determination methods based on the indicated modifiers have been developed. In each case, pyrolysis and atomization temperatures, atomization shapes, characteristic masses and detection limits as well as other analytical characteristics have been determined. All the assayed modifiers (permanent and conventional) were capable of achieving the appropriate stabilization of the analyte, with the exception of Ru and W-Ru. Moreover, for all developed methods, recoveries (99-102%) and precision (R.S.D. lower than 10%) were acceptable. Taking into account the analytical performance (best detection limit LOD = 0.01 μg L -1 ), the ETAAS method based on the use of W as a permanent modifier was selected for further direct Cd determinations in Orujo samples from Galicia (NW Spain). The chosen method was applied in the determination of the Cd content in 38 representative Galician samples. The cadmium concentrations ranged -1

  8. Analysis of Chemical Bioactivity through In Vitro Profiling ...

    Science.gov (United States)

    Safety assessment of drugs and environmental chemicals relies extensively on animal testing. However, the quantity of chemicals needing assessment and challenges of species extrapolation drive the development of alternative approaches. The EPA’s ToxCast and the multiagency Tox21 programs address this through use of an extensive in vitro screening program to generate data on a large library of important environmental chemicals. These in vitro assays encompass both cell-free, biochemical assays targeting proteins that may be potential molecular initiating events and cellular assays that provide coverage of critical signaling pathways and toxicity phenotypes. Effects on model organisms such as the developing zebrafish, are also part of the testing strategy. A variety of computational approaches are used to analyze the resulting complex data sets to gain insight in to inherent biological activity of chemicals and possible mechanisms of toxicity. Several case studies including identification of modulators of estrogen receptor and aromatic hydrocarbon receptor pathways with effects in primary human cell systems will be described. In addition, existing in vivo data from a subset of the chemicals was used to anchor predictive models using in vitro data for a number of adverse endpoints including reproductive and developmental toxicities. The strengths and weaknesses of this approach will be described. This work does not necessarily reflect official Agency policy. Pres

  9. Cheminformatics Analysis of EPA ToxCast Chemical Libraries ...

    Science.gov (United States)

    An important goal of toxicology research is the development of robust methods that use in vitro and chemical structure information to predict in vivo toxicity endpoints. The US EPA ToxCast program is addressing this goal using ~600 in vitro assays to create bioactivity profiles on a set of 320 compounds, mostly pesticide actives, that have well characterized in vivo toxicity. These 320 compounds (EPA-320 set evaluated in Phase I of ToxCast) are a subset of a much larger set of ~10,000 candidates that are of interest to the EPA (called here EPA-10K). Predictive models of in vivo toxicity are being constructed from the in vitro assay data on the EPA-320 chemical set. These models require validation on additional chemicals prior to wide acceptance, and this will be carried out by evaluating compounds from EPA-10K in Phase II of ToxCast. We have used cheminformatics approaches including clustering, data visualization, and QSAR to develop models for EPA-320 that could help prioritizing EPA-10K validation chemicals. Both chemical descriptors, as well as calculated physicochemical properties have been used. Compounds from EPA-10K are prioritized based on their similarity to EPA-320 using different similarity metrics, with similarity thresholds defining the domain of applicability for the predictive models built for EPA-320 set. In addition, prioritized lists of compounds of increasing dissimilarity from the EPA-320 have been produced, to test the ability of the EPA-320

  10. Energy and environment efficiency analysis based on an improved environment DEA cross-model: Case study of complex chemical processes

    International Nuclear Information System (INIS)

    Geng, ZhiQiang; Dong, JunGen; Han, YongMing; Zhu, QunXiong

    2017-01-01

    Highlights: •An improved environment DEA cross-model method is proposed. •Energy and environment efficiency analysis framework of complex chemical processes is obtained. •This proposed method is efficient in energy-saving and emission reduction of complex chemical processes. -- Abstract: The complex chemical process is a high pollution and high energy consumption industrial process. Therefore, it is very important to analyze and evaluate the energy and environment efficiency of the complex chemical process. Data Envelopment Analysis (DEA) is used to evaluate the relative effectiveness of decision-making units (DMUs). However, the traditional DEA method usually cannot genuinely distinguish the effective and inefficient DMU due to its extreme or unreasonable weight distribution of input and output variables. Therefore, this paper proposes an energy and environment efficiency analysis method based on an improved environment DEA cross-model (DEACM) method. The inputs of the complex chemical process are divided into energy and non-energy inputs. Meanwhile, the outputs are divided into desirable and undesirable outputs. And then the energy and environment performance index (EEPI) based on the cross evaluation is used to represent the overall performance of each DMU. Moreover, the improvement direction of energy-saving and carbon emission reduction of each inefficiency DMU is quantitatively obtained based on the self-evaluation model of the improved environment DEACM. The results show that the improved environment DEACM method has a better effective discrimination than the original DEA method by analyzing the energy and environment efficiency of the ethylene production process in complex chemical processes, and it can obtain the potential of energy-saving and carbon emission reduction of ethylene plants, especially the improvement direction of inefficient DMUs to improve energy efficiency and reduce carbon emission.

  11. Direct growth of Ge1-xSnx films on Si using a cold-wall ultra-high-vacuum chemical-vapor-deposition system

    Directory of Open Access Journals (Sweden)

    Aboozar eMosleh

    2015-04-01

    Full Text Available Germanium tin alloys were grown directly on Si substrate at low temperatures using a cold-wall ultra-high vacuum chemical vapor deposition system. Epitaxial growth was achieved by adopting commercial gas precursors of germane and stannic chloride without any carrier gases. The X-ray diffraction analysis showed the incorporation of Sn and that the Ge1-xSnx films are fully epitaxial and strain relaxed. Tin incorporation in the Ge matrix was found to vary from 1% to 7%. The scanning electron microscopy images and energy dispersive X-ray spectra maps show uniform Sn incorporation and continuous film growth. Investigation of deposition parameters shows that at high flow rates of stannic chloride the films were etched due to the production of HCl. The photoluminescence study shows the reduction of bandgap from 0.8 eV to 0.55 eV as a result of Sn incorporation.

  12. X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis

    Science.gov (United States)

    Roine, J.; Tenho, M.; Murtomaa, M.; Lehto, V.-P.; Kansanaho, R.

    2007-10-01

    The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers.

  13. Direct-reading spectrochemical analysis of soils and plant ashes

    International Nuclear Information System (INIS)

    Roca, M.; Alvarez, F.; Cellini, R. F.; Burriel, F.

    1966-01-01

    Two different techniques haves been tried to determine trace elements in soils and plant ashes using a direct reading spectrometer :1) the samples are mixed with graphite powder and excited on 2x4 mm graphite rods with a 13 amperes direct current arc: 2) a mixture of graphite and strontium carbonate is used as spectrochemical buffer, and 2x6 mm cup graphite rods in a 10 amperes direct current arc. We have studies the influence of sodium, potassium and calcium on the results. (Author)

  14. International Research Project on the Effects of Chemical Ageing of Polymers on Performance Properties: Chemical and Thermal Analysis

    Science.gov (United States)

    Bulluck, J. W.; Rushing, R. A.

    1996-01-01

    Work during the past six months has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted small changes in the molecular weight distribution. Again these changes may result in variations in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Ultra- Violet Scanning Analysis, GC/Mass Spectrometry, Differential Scanning Calorimetry and Thermomechanical Analysis. In the ultra-violet analysis we noted the presence of an absorption band indicative of triene formation. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We also cast films at SWT and subjected these films to a refluxing methanol 1% ethylene diamine solution. An updated literature search was conducted using Dialog and DROLLS to identify any new papers that may have been published in the open literature since the start of this project. The updated literature search and abstracts are contained in the Appendix section of this report.

  15. Comparative Analysis of Direct and Indirect Property Investment ...

    African Journals Online (AJOL)

    Sultan

    substitute for direct property investment in Abuja, Nigeria. The study .... of stock market investment using Lagos,. Ibadan and ... ordinary shares and saving account for the. Adeogun ... Hence, the need for this study which provides information.

  16. Causality Analysis of the Impact of Foreign Direct Investment on ...

    African Journals Online (AJOL)

    Having established the fact that foreign direct investment has positive impact on growth domestic product ...... on Sharing Global Prosperity, September. 2003, Helsinki, Finland. ... Evidence from East Asia and Latin. America, Contemp. Econ.

  17. Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

    Science.gov (United States)

    Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protectingit from chemical contamination is a major societal goal in the European Union. The Water Framework Directive(WFD) and its daughter directives are the major body of ...

  18. Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

    NARCIS (Netherlands)

    Brack, W.; Dulio, V.; Agerstrand, M.; Allan, I.; Altenburger, R.; Brinkmann, M.; Bunke, D.; Burgess, R.M.; Cousins, I.; Escher, B.I.; Hernandez, F.J.; Hewitt, L.M.; Hilscherova, K.; Hollender, J.; Hollert, H.; Kase, R.; Klauer, B.; Lindim, C.; Herraez, D.L.; Miege, C.; Munthe, J.; O'Toole, S.; Posthuma, L.; Rudel, H.; Schafer, R.B.; Sengl, M.; Smedes, F.; van de Meent, D.; van den Brink, P.J.; van Gils, J.; van Wezel, A.P.; Vethaak, A.D.; Vermeirssen, E.; von der Ohe, P.C.; Vrana, B.

    2017-01-01

    Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for

  19. Chemical Analysis of Counterfeit Hepatitis C Drug Found in Japan.

    Science.gov (United States)

    Uchiyama, Nahoko; Kamakura, Hiroyuki; Masada, Sayaka; Tsujimoto, Takashi; Hosoe, Junko; Tokumoto, Hiroko; Maruyama, Takuro; Goda, Yukihiro; Hakamatsuka, Takashi

    2017-10-01

    In January 2017, counterfeits of the hepatitis C drug 'HARVONI ® Combination Tablets' (HARVONI ® ) were found at a pharmacy chain through unlicensed suppliers in Japan. A total of five lots of counterfeit HARVONI ® (samples 1-5) bottles were found, and the ingredients of the bottles were all in tablet form. Among them, two differently shaped tablets were present in two of the bottles (categorized as samples 2A, 2B, 4A, and 4B). We analyzed the total of seven samples by high-resolution LC-MS, GC-MS and NMR. In samples 2A, 3 and 4B, sofosbuvir, the active component of another hepatitis C drug, SOVALDI ® Tablets 400 mg (SOVALDI ® ), was detected. In sample 4A, sofosbuvir and ledipasvir, the active components of HARVONI ® , were found. A direct comparison of the four samples and genuine products showed that three samples (2A, 3, 4B) are apparently SOVALDI ® and that sample 2A is HARVONI ® . In samples 1 and 5, several vitamins but none of the active compounds usually found in HARVONI ® (i.e., sofosbuvir and ledipasvir) were detected. Our additional investigation indicates that these two samples are likely to be a commercial vitamin supplement distributed in Japan. Sample 2B, looked entirely different from HARVONI ® and contained several herbal constitutents (such as ephedrine and glycyrrhizin) that are used in Japanese Kampo formulations. A further analysis indicated that sample 2B is likely to be a Kampo extract tablet of Shoseiryuto which is distributed in Japan. Considering this case, it is important to be vigilant to prevent a recurrence of distribution of counterfeit drugs.

  20. Analysis of primary cilia in directional cell migration in fibroblasts

    DEFF Research Database (Denmark)

    Christensen, Søren Tvorup; Veland, Iben; Schwab, Albrecht

    2013-01-01

    summarize selected methods in analyzing ciliary function in directional cell migration, including immunofluorescence microscopy, scratch assay, and chemotaxis assay by micropipette addition of PDGFRα ligands to cultures of fibroblasts. These methods should be useful not only in studying cell migration....... In particular, platelet-derived growth factor receptor alpha (PDGFRα) is compartmentalized to the primary cilium to activate signaling pathways that regulate reorganization of the cytoskeleton required for lamellipodium formation and directional migration in the presence of a specific ligand gradient. We...

  1. Direct synthesis of solid and hollow carbon nanospheres over NaCl crystals using acetylene by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chandra Kishore, S.; Anandhakumar, S.; Sasidharan, M., E-mail: sasidharan.m@res.srmuniv.ac.in

    2017-04-01

    Highlights: • Hollow and solid carbon nanospheres were synthesized by CVD method. • NaCl was used as template for direct growth of carbon nanospheres. • Separation of NaCl from the mixture is made easy by dissolving in water. • The hollow carbon nanospheres exhibit high specific capacity in Li-ion batteries than the graphite anodes. - Abstract: Carbon nanospheres (CNS) with hollow and solid morphologies have been synthesised by a simple chemical vapour deposition method using acetylene as a carbon precursor. Sodium chloride (NaCl) powder as a template was used for the direct growth of CNS via facile and low-cost approach. The effect of various temperatures (500 °C, 600 °C and 700 °C) and acetylene flow rates were investigated to study the structural evolution on the carbon products. The purified CNS thus obtained was characterized by various physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and cyclicvoltametry. The synthesised hollow nanospheres were investigated as anode materials for Li-ion batteries. After 25 cycles of repeated charge/discharge cycles, the discharge and charge capacities were found to be 574 mAh/g and 570 mAh/g, respectively which are significantly higher than the commercial graphite samples.

  2. Seveso II directive in prevention and mitigation of consequences of chemical terrorism, safety management systems in hazardous installations

    International Nuclear Information System (INIS)

    Klicek, M.

    2009-01-01

    Mayor accidents caused by hazardous substances are great threat to public. The consequences are often very severe with great number of injured people or even deaths and a great material damage. Statistic data shows that the main cause of accidents in hazardous installations is 'human factor', including the possibility of terrorist attack, or classic military operations. In order to ensure effective chemical safety, the actions should be taken by industry, public authorities, communities and other stake holders to prevent industrial accidents. Safety should be an integral part of the business activities of an enterprise, and all hazardous installations should strive to reach the ultimate goal of zero incidents. Safety management systems (SMS) should include appropriate technology and processes, as well as establishing an effective organisational structure. To mitigate consequences of accidents, emergency planning, land-use planning and risk communication is necessary. Adequate response in the event of accident should limit adverse consequences to health, environment and property. Follow-up actions are needed to learn from the accidents and other unexpected events, in order to reduce future incidents. In this paper the author will discus the implementing of SEVESO II directive in obtaining two main goals: major accident prevention and mitigation of consequences for men and environment in case of possible terrorist actions or military activities. Some Croatian experiences in implementing of UNEP APELL Programme, and its connection with SEVESO II directive will be shown.(author)

  3. A path flux analysis method for the reduction of detailed chemical kinetic mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenting; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871 (China); Gou, Xiaolong [School of Power Engineering, Chongqing University, Chongqing 400044 (China)

    2010-07-15

    A direct path flux analysis (PFA) method for kinetic mechanism reduction is proposed and validated by using high temperature ignition, perfect stirred reactors, and steady and unsteady flame propagations of n-heptane and n-decane/air mixtures. The formation and consumption fluxes of each species at multiple reaction path generations are analyzed and used to identify the important reaction pathways and the associated species. The formation and consumption path fluxes used in this method retain flux conservation information and are used to define the path indexes for the first and the second generation reaction paths related to a targeted species. Based on the indexes of each reaction path for the first and second generations, different sized reduced chemical mechanisms which contain different number of species are generated. The reduced mechanisms of n-heptane and n-decane obtained by using the present method are compared to those generated by the direct relation graph (DRG) method. The reaction path analysis for n-decane is conducted to demonstrate the validity of the present method. The comparisons of the ignition delay times, flame propagation speeds, flame structures, and unsteady spherical flame propagation processes showed that with either the same or significantly less number of species, the reduced mechanisms generated by the present PFA are more accurate than that of DRG in a broad range of initial pressures and temperatures. The method is also integrated with the dynamic multi-timescale method and a further increase of computation efficiency is achieved. (author)

  4. Chemical analysis and biological potential of Valerian root as used ...

    African Journals Online (AJOL)

    The herb prepared from this plant was studied to determine the chemical composition of its essential oil, carried out phytochemical screening and biological activities on ... rat paw oedema model comparable to aspirin, indicating anti-inflammatory activity; but lacked analgesic activity on the acetic acid-induced writhing test.

  5. HBCUs and Chemical Engineering: Analysis of Baccalaureate Programs

    Science.gov (United States)

    Reeves, Sheena; Thompson, Audie

    2018-01-01

    Historically Black Colleges and Universities (HBCUs) provide significant STEM degrees to African Americans. Initiatives toward increasing diversity in STEM fields have been implemented by government and industry leaders. HBCUs annually award over 20% of all African American baccalaureate chemical engineering degrees. This speaks volume to the…

  6. Chemical analysis of the Assale (Ethiopia) rock salt deposit | Binega ...

    African Journals Online (AJOL)

    contaminants) elements found in the Assale (Ethiopia) rock salt. The results showed that the rock salt is found to be the best natural common salt. This was proved by comparison with the chemical requirement and trace elements in common ...

  7. Probabilistic thermo-chemical analysis of a pultruded composite rod

    DEFF Research Database (Denmark)

    Baran, Ismet; Tutum, Cem Celal; Hattel, Jesper Henri

    2012-01-01

    In the present study the deterministic thermo-chemical pultrusion simulation of a composite rod taken from the literature [7] is used as a validation case. The predicted centerline temperature and cure degree profiles of the rod match well with those in the literature [7]. Following the validation...

  8. Fatty acid composition and its association with chemical and sensory analysis of boar taint.

    Science.gov (United States)

    Liu, Xiaoye; Trautmann, Johanna; Wigger, Ruth; Zhou, Guanghong; Mörlein, Daniel

    2017-09-15

    A certain level of disagreement between the chemical analysis of androstenone and skatole and the human perception of boar taint has been found in many studies. Here we analyze whether the fatty acid composition can explain such inconsistency between sensory evaluation and chemical analysis of boar taint compounds. Therefore, back fat samples (n=143) were selected according to their sensory evaluation by a 10-person sensory panel, and the chemical analysis (stable isotope dilution analysis with headspace solid-phase microextraction and gas chromatography-mass spectrometry) of androstenone and skatole. Subsequently a quantification of fatty acids using gas chromatography-flame ionization detection was conducted. The correlation analyses revealed that several fatty acids are significantly correlated with androstenone, skatole, and the sensory rating. However, multivariate analyses (principal component analysis) revealed no explanation of the fatty acid composition with respect to the (dis-)agreement between sensory and chemical analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Direct push driven in situ color logging tool (CLT): technique, analysis routines, and application

    Science.gov (United States)

    Werban, U.; Hausmann, J.; Dietrich, P.; Vienken, T.

    2014-12-01

    Direct push technologies have recently seen a broad development providing several tools for in situ parameterization of unconsolidated sediments. One of these techniques is the measurement of soil colors - a proxy information that reveals to soil/sediment properties. We introduce the direct push driven color logging tool (CLT) for real-time and depth-resolved investigation of soil colors within the visible spectrum. Until now, no routines exist on how to handle high-resolved (mm-scale) soil color data. To develop such a routine, we transform raw data (CIEXYZ) into soil color surrogates of selected color spaces (CIExyY, CIEL*a*b*, CIEL*c*h*, sRGB) and denoise small-scale natural variability by Haar and Daublet4 wavelet transformation, gathering interpretable color logs over depth. However, interpreting color log data as a single application remains challenging. Additional information, such as site-specific knowledge of the geological setting, is required to correlate soil color data to specific layers properties. Hence, we exemplary provide results from a joint interpretation of in situ-obtained soil color data and 'state-of-the-art' direct push based profiling tool data and discuss the benefit of additional data. The developed routine is capable of transferring the provided information obtained as colorimetric data into interpretable color surrogates. Soil color data proved to correlate with small-scale lithological/chemical changes (e.g., grain size, oxidative and reductive conditions), especially when combined with additional direct push vertical high resolution data (e.g., cone penetration testing and soil sampling). Thus, the technique allows enhanced profiling by means of providing another reproducible high-resolution parameter for analysis subsurface conditions. This opens potential new areas of application and new outputs for such data in site investigation. It is our intention to improve color measurements by means method of application and data

  10. CHEMICAL ANALYSIS OF DENSE-GAS EXTRACTS FROM LIME FLOWERS

    Directory of Open Access Journals (Sweden)

    Demyanenko DV

    2015-04-01

    Full Text Available The purpose of this work was to make qualitative and quantitative analysis of phenolic biologically active substances (BAS in the extracts produced from lime flowers with condensed gases, using method of high-performance liquid chromatography (HPLC. Materials and methods: materials for this study were the extracts obtained by consequent processing of the herbal drug and marcs thereof with various condensed gases: difluorochloromethane (Freon R22, difluoromethane (Freon R32, azeotropic mixture of difluoromethane with pentafluoroethane (Freon 410A and freon-ammonium mixture. Extracts obtained with the latter were subjected to further fractionation by liquidliquid separation into hexane, chloroform, ethyl acetate and aqueous-alcohol phases. Besides, the supercritical СО2 extract, obtained from the herbal drug under rather strong conditions (at temperature 60°С and pressure 400 bar, was studied in our previous research. Presence of phenolic BAS and their quantity in the researched samples were determined by method of HPLC with UVspectrometric detection. Results and discussion: It has been found that Freon R22 extracted trace amounts of rutin from lime flowers – its content was only 0.08% of the total extract weight. On the other hand, Freons R32 and R410А showed good selectivity to moderately polar BAS of lime flowers (derivatives of flavonoids and hydroxycinnamic acids: in particular, the extract obtained with freon R32 contained about 1.3% of the total phenolic substances, and it was the only one of the investigated condensed gases used by us which took the basic flavonoid of lime flowers tiliroside – its content was 0.42% of extract weight. Also Freons R32 and R410А were able to withdraw another compound dominating among phenolic substances in the yielded extracts. Its quantity was rather noticeable – up to 0.87% of extract weight. This substance was not identified by existing database, but its UV-spectrum was similar to those of

  11. Direct Analysis in Real Time Mass Spectrometry for Characterization of Large Saccharides.

    Science.gov (United States)

    Ma, Huiying; Jiang, Qing; Dai, Diya; Li, Hongli; Bi, Wentao; Da Yong Chen, David

    2018-03-06

    Polysaccharide characterization posts the most difficult challenge to available analytical technologies compared to other types of biomolecules. Plant polysaccharides are reported to have numerous medicinal values, but their effect can be different based on the types of plants, and even regions of productions and conditions of cultivation. However, the molecular basis of the differences of these polysaccharides is largely unknown. In this study, direct analysis in real time mass spectrometry (DART-MS) was used to generate polysaccharide fingerprints. Large saccharides can break down into characteristic small fragments in the DART source via pyrolysis, and the products are then detected by high resolution MS. Temperature was shown to be a crucial parameter for the decomposition of large polysaccharide. The general behavior of carbohydrates in DART-MS was also studied through the investigation of a number of mono- and oligosaccharide standards. The chemical formula and putative ionic forms of the fragments were proposed based on accurate mass with less than 10 ppm mass errors. Multivariate data analysis shows the clear differentiation of different plant species. Intensities of marker ions compared among samples also showed obvious differences. The combination of DART-MS analysis and mechanochemical extraction method used in this work demonstrates a simple, fast, and high throughput analytical protocol for the efficient evaluation of molecular features in plant polysaccharides.

  12. Application of Raman spectroscopy for direct analysis of Carlina acanthifolia subsp. utzka root essential oil.

    Science.gov (United States)

    Strzemski, Maciej; Wójciak-Kosior, Magdalena; Sowa, Ireneusz; Agacka-Mołdoch, Monika; Drączkowski, Piotr; Matosiuk, Dariusz; Kurach, Łukasz; Kocjan, Ryszard; Dresler, Sławomir

    2017-11-01

    Carlina genus plants e.g. Carlina acanthifolia subsp. utzka have been still used in folk medicine of many European countries and its biological activity is mostly associated with root essential oils. In the present paper, Raman spectroscopy (RS) was applied for the first time for evaluation of essential oil distribution in root of C. acnthifolia subsp. utzka and identification of root structures containing the essential oil. Furthermore, RS technique was applied to assess chemical stability of oil during drying of plant material or distillation process. Gas chromatography-mass spectrometry was used for qualitative and quantitative analysis of the essential oil. The identity of compounds was confirmed using Raman, ATR-IR and NMR spectroscopy. Carlina oxide was found to be the main component of the oil (98.96% ± 0.15). The spectroscopic study showed the high stability of essential oil and Raman distribution analysis indicated that the oil reservoirs were localized mostly in the structures of outer layer of the root while the inner part showed nearly no signal assigned to the oil. Raman spectroscopy technique enabled rapid, non-destructive direct analysis of plant material with minimal sample preparation and allowed straightforward, unambiguous identification of the essential oil in the sample. Copyright © 2017. Published by Elsevier B.V.

  13. Chemical composition and source of fine and nanoparticles from recent direct injection gasoline passenger cars: Effects of fuel and ambient temperature

    Science.gov (United States)

    Fushimi, Akihiro; Kondo, Yoshinori; Kobayashi, Shinji; Fujitani, Yuji; Saitoh, Katsumi; Takami, Akinori; Tanabe, Kiyoshi

    2016-01-01

    Particle number, mass, and chemical compositions (i.e., elemental carbon (EC), organic carbon (OC), elements, ions, and organic species) of fine particles emitted from four of the recent direct injection spark ignition (DISI) gasoline passenger cars and a port fuel injection (PFI) gasoline passenger car were measured under Japanese official transient mode (JC08 mode). Total carbon (TC = EC + OC) dominated the particulate mass (90% on average). EC dominated the TC for both hot and cold start conditions. The EC/TC ratios were 0.72 for PFI and 0.88-1.0 (average = 0.92) for DISI vehicles. A size-resolved chemical analysis of a DISI car revealed that the major organic components were the C20-C28 hydrocarbons for both the accumulation-mode particles and nanoparticles. Contribution of engine oil was estimated to be 10-30% for organics and the sum of the measured elements. The remaining major fraction likely originated from gasoline fuel. Therefore, it is suggested that soot (EC) also mainly originated from the gasoline. In experiments using four fuels at three ambient temperatures, the emission factors of particulate mass were consistently higher with regular gasoline than with premium gasoline. This result suggest that the high content of less-volatile compounds in fuel increase particulate emissions. These results suggest that focusing on reducing fuel-derived EC in the production process of new cars would effectively reduce particulate emission from DISI cars.

  14. Mean-field level analysis of epidemics in directed networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiazeng [School of Mathematical Sciences, Peking University, Beijing 100871 (China); Liu, Zengrong [Mathematics Department, Shanghai University, Shanghai 200444 (China)], E-mail: wangjiazen@yahoo.com.cn, E-mail: zrongliu@online.sh.cn

    2009-09-04

    The susceptible-infected-removed spreading model in a directed graph is studied. The mean-field level rate equations are built with the degree-degree connectivity correlation element and the (in, out)-degree distribution. And the outbreak threshold is obtained analytically-it is determined by the combination of connectivity probability and the degree distribution. Furthermore, the methods of calculating the degree-degree correlations in directed networks are presented. The numerical results of the discrete epidemic processes in networks verify our analyses.

  15. Mean-field level analysis of epidemics in directed networks

    International Nuclear Information System (INIS)

    Wang, Jiazeng; Liu, Zengrong

    2009-01-01

    The susceptible-infected-removed spreading model in a directed graph is studied. The mean-field level rate equations are built with the degree-degree connectivity correlation element and the (in, out)-degree distribution. And the outbreak threshold is obtained analytically-it is determined by the combination of connectivity probability and the degree distribution. Furthermore, the methods of calculating the degree-degree correlations in directed networks are presented. The numerical results of the discrete epidemic processes in networks verify our analyses.

  16. Data Analysis Trumps Specialist Advice: How Direct Banks Function

    Directory of Open Access Journals (Sweden)

    Skiera Bernd

    2016-11-01

    Full Text Available Low interest rates and sluggish economic growth are not exactly ideal conditions for the financial services industry. Almost daily we are confronted with reports of inadequate capital bases, declining earnings, and layoffs at banks. But while many traditional retail banks are struggling with a business downturn, the direct bank market is enjoying steady and respectable growth despite a challenging environment. Dr. Schmidberger, Fully Authorized Representative at ING-DiBa Germany, offers us a glimpse behind the curtains of this direct bank. We will learn how data technology is used so that bank customers are (more satisfied.

  17. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    International Nuclear Information System (INIS)

    Turek, M.; Heiden, W.; Riesen, A.; Chhabda, T.A.; Schubert, J.; Zander, W.; Krueger, P.; Keusgen, M.; Schoening, M.J.

    2009-01-01

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  18. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Turek, M. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Heiden, W.; Riesen, A. [Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin (Germany); Chhabda, T.A. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Schubert, J.; Zander, W. [Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Krueger, P. [Institute of Biochemistry and Molecular Biology, RWTH Aachen, Aachen (Germany); Keusgen, M. [Institute for Pharmaceutical Chemistry, Philipps-University Marburg, Marburg (Germany); Schoening, M.J. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany)], E-mail: m.j.schoening@fz-juelich.de

    2009-10-30

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  19. Effect-directed analysis supporting monitoring of aquatic environments — An in-depth overview

    NARCIS (Netherlands)

    Brack, W.; Ait-Aissa, S.; Burgess, R.M.; Creusot, N.; Di Paolo, C.; Escher, B.I.; Hewitt, L.M.; Hilscherova, K.; Hollender, J.; Hollert, H.; Jonker, W.; Kool, J.; Lamoree, M.H.; Muschket, M.; Neumann, S.; Rostkowski, P.; Ruttkies, C.; Schollee, J.; Schymanski, E.L.; Schulze, T.; Seiler, T.; Tindall, A.J.; De Aragão Umbuzeiro, G.; Vrana, B.; Krauss, M.

    2016-01-01

    Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone but tools are required to reduce this complexity and identify those chemicals that might cause adverse

  20. Silica sol as grouting material: a physio-chemical analysis.

    Science.gov (United States)

    Sögaard, Christian; Funehag, Johan; Abbas, Zareen

    2018-01-01

    At present there is a pressing need to find an environmentally friendly grouting material for the construction of tunnels. Silica nanoparticles hold great potential of replacing the organic molecule based grouting materials currently used for this purpose. Chemically, silica nanoparticles are similar to natural silicates which are essential components of rocks and soil. Moreover, suspensions of silica nanoparticles of different sizes and desired reactivity are commercially available. However, the use of silica nanoparticles as grouting material is at an early stage of its technological development. There are some critical parameters such as long term stability and functionality of grouted silica that need to be investigated in detail before silica nanoparticles can be considered as a reliable grouting material. In this review article we present the state of the art regarding the chemical properties of silica nanoparticles commercially available, as well as experience gained from the use of silica as grouting material. We give a detailed description of the mechanisms underlying the gelling of silica by different salt solutions such as NaCl and KCl and how factors such as particle size, pH, and temperature affect the gelling and gel strength development. Our focus in this review is on linking the chemical properties of silica nanoparticles to the mechanical properties to better understand their functionality and stability as grouting material. Along the way we point out areas which need further research.

  1. Miniaturised wireless smart tag for optical chemical analysis applications.

    Science.gov (United States)

    Steinberg, Matthew D; Kassal, Petar; Tkalčec, Biserka; Murković Steinberg, Ivana

    2014-01-01

    A novel miniaturised photometer has been developed as an ultra-portable and mobile analytical chemical instrument. The low-cost photometer presents a paradigm shift in mobile chemical sensor instrumentation because it is built around a contactless smart card format. The photometer tag is based on the radio-frequency identification (RFID) smart card system, which provides short-range wireless data and power transfer between the photometer and a proximal reader, and which allows the reader to also energise the photometer by near field electromagnetic induction. RFID is set to become a key enabling technology of the Internet-of-Things (IoT), hence devices such as the photometer described here will enable numerous mobile, wearable and vanguard chemical sensing applications in the emerging connected world. In the work presented here, we demonstrate the characterisation of a low-power RFID wireless sensor tag with an LED/photodiode-based photometric input. The performance of the wireless photometer has been tested through two different model analytical applications. The first is photometry in solution, where colour intensity as a function of dye concentration was measured. The second is an ion-selective optode system in which potassium ion concentrations were determined by using previously well characterised bulk optode membranes. The analytical performance of the wireless photometer smart tag is clearly demonstrated by these optical absorption-based analytical experiments, with excellent data agreement to a reference laboratory instrument. © 2013 Elsevier B.V. All rights reserved.

  2. An Analysis of Chinese Foreign Direct Investment (FDI) in Sub ...

    African Journals Online (AJOL)

    user

    In line with this,. China has bilateral trade and economic cooperation with many sub-Saharan. African countries. 4.2 Trends of Chinese FDI across sectors and Countries. China has become the leading country in foreign direct investment in Africa. During the year 2011, trade between Africa and China increased a staggering.

  3. Image analysis software versus direct anthropometry for breast measurements.

    Science.gov (United States)

    Quieregatto, Paulo Rogério; Hochman, Bernardo; Furtado, Fabianne; Machado, Aline Fernanda Perez; Sabino Neto, Miguel; Ferreira, Lydia Masako

    2014-10-01

    To compare breast measurements performed using the software packages ImageTool(r), AutoCAD(r) and Adobe Photoshop(r) with direct anthropometric measurements. Points were marked on the breasts and arms of 40 volunteer women aged between 18 and 60 years. When connecting the points, seven linear segments and one angular measurement on each half of the body, and one medial segment common to both body halves were defined. The volunteers were photographed in a standardized manner. Photogrammetric measurements were performed by three independent observers using the three software packages and compared to direct anthropometric measurements made with calipers and a protractor. Measurements obtained with AutoCAD(r) were the most reproducible and those made with ImageTool(r) were the most similar to direct anthropometry, while measurements with Adobe Photoshop(r) showed the largest differences. Except for angular measurements, significant differences were found between measurements of line segments made using the three software packages and those obtained by direct anthropometry. AutoCAD(r) provided the highest precision and intermediate accuracy; ImageTool(r) had the highest accuracy and lowest precision; and Adobe Photoshop(r) showed intermediate precision and the worst accuracy among the three software packages.

  4. Stability analysis of direct current control in current source rectifier

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...

  5. Use of direct gradient analysis to uncover biological hypotheses in 16s survey data and beyond.

    Science.gov (United States)

    Erb-Downward, John R; Sadighi Akha, Amir A; Wang, Juan; Shen, Ning; He, Bei; Martinez, Fernando J; Gyetko, Margaret R; Curtis, Jeffrey L; Huffnagle, Gary B

    2012-01-01

    This study investigated the use of direct gradient analysis of bacterial 16S pyrosequencing surveys to identify relevant bacterial community signals in the midst of a "noisy" background, and to facilitate hypothesis-testing both within and beyond the realm of ecological surveys. The results, utilizing 3 different real world data sets, demonstrate the utility of adding direct gradient analysis to any analysis that draws conclusions from indirect methods such as Principal Component Analysis (PCA) and Principal Coordinates Analysis (PCoA). Direct gradient analysis produces testable models, and can identify significant patterns in the midst of noisy data. Additionally, we demonstrate that direct gradient analysis can be used with other kinds of multivariate data sets, such as flow cytometric data, to identify differentially expressed populations. The results of this study demonstrate the utility of direct gradient analysis in microbial ecology and in other areas of research where large multivariate data sets are involved.

  6. Efficiency analysis of Chinese industry: A directional distance function approach

    International Nuclear Information System (INIS)

    Watanabe, Michio; Tanaka, Katsuya

    2007-01-01

    Two efficiency measures of Chinese industry were estimated at the provincial level from 1994 to 2002, using a directional output distance function. One is a traditional efficiency measure that considers only desirable output, while the other considers both desirable and undesirable outputs simultaneously. A comparison of the two measures revealed that efficiency levels are biased only if desirable output is considered. Five coastal provinces/municipalities that have attracted a large amount of foreign direct investment are found to be the most efficient when only desirable output is considered, and also when both desirable and undesirable outputs are considered. However, omitting undesirable output tends to lead to an overestimate of industrial efficiency levels in Shandong, Sichuan, and Hebei provinces. We also found that a province's industrial structure has significant effects on its efficiency levels

  7. A comparative analysis of foreign direct investment factors

    OpenAIRE

    Miškinis, Algirdas; Juozėnaitė, Ilma

    2015-01-01

    The paper identifies factors affecting the foreign direct investment (FDI) inflow. It analyzes the determinants of FDI in recent empirical evidence as well as determines differences among FDI factors in Greece, Ireland, and the Netherlands. The determinants being examined are the gross domestic product (GDP) per capita, exchange rate, unit labor costs, trade openness as well as inflation. The analyzed period is 1974–2012. Data were collected from the World Bank and the Organization for Econom...

  8. Direct-reading spectrochemical analysis of magnesium alloys

    International Nuclear Information System (INIS)

    Roca Adell, M.

    1964-01-01

    A Quantometer has been applied to the determination of aluminum, berylium, calcium, iron, silicon and zinc in magnesium alloys Magnox, after the conversion of the samples to the oxide. For the aluminum, whose concentration is relatively high, the conducting briquets technique with an interrupted discharge is employed, using the magnesium as the internal standard. For the other elements a total burning method with direct current arc is employed, using also the magnesium as the internal standard. (Author) 7 refs

  9. A wave parameters and directional spectrum analysis for extreme winds

    OpenAIRE

    Montoya Ramírez, Rubén Darío; Osorio Arias, Andres Fernando; Ortiz Royero, Juan Carlos; Ocampo-Torres, Francisco Javier

    2013-01-01

    In this research a comparison between two of the most popular ocean wave models, WAVEWATCH III™ and SWAN, was performed using data from hurricane Katrina in the Gulf of Mexico. The numerical simulation of sea surface directional wave spectrum and other wave parameters for several parameter- izations and its relation with the drag coefficient was carried out. The simulated data were compared with in-situ NOAA buoy data. For most of the buoys, WAVEWATCH III™ presented the best statistical compar...

  10. Forecasting global developments in the basic chemical industry for environmental policy analysis

    NARCIS (Netherlands)

    Broeren, M.L.M.|info:eu-repo/dai/nl/371687438; Saygin, D.; Patel, M.K.

    The chemical sector is the largest industrial energy user, but detailed analysis of its energy use developments lags behind other energy-intensive sectors. A cost-driven forecasting model for basic chemicals production is developed, accounting for regional production costs, demand growth and stock

  11. Chemical Analysis of the Moon at the Surveyor VII Landing Site: Preliminary Results.

    Science.gov (United States)

    Turkevich, A L; Franzgrote, E J; Patterson, J H

    1968-10-04

    The alpha-scattering experiment aboard Surveyor VII has provided a chemical analysis of the moon in the area of the crater Tycho. The preliminary results indicate a chemical composition similar to that already found at two mare sites, but with a lower concentration of elements of the iron group (titanium through copper).

  12. Exploring the Potential for Using Inexpensive Natural Reagents Extracted from Plants to Teach Chemical Analysis

    Science.gov (United States)

    Hartwell, Supaporn Kradtap

    2012-01-01

    A number of scientific articles report on the use of natural extracts from plants as chemical reagents, where the main objective is to present the scientific applications of those natural plant extracts. The author suggests that natural reagents extracted from plants can be used as alternative low cost tools in teaching chemical analysis,…

  13. Sample preparation for combined chemical analysis and bioassay application in water quality assessment

    NARCIS (Netherlands)

    Kolkman, A.; Schriks, M.; Brand, W; Bäuerlein, P.S.; van der Kooi, M.M.E.; van Doorn, R.H.; Emke, E.; Reus, A.; van der Linden, S.; de Voogt, P.; Heringa, M.B.

    2013-01-01

    The combination of in vitro bioassays and chemical screening can provide a powerful toolbox to determine biologically relevant compounds in water extracts. In this study, a sample preparation method is evaluated for the suitability for both chemical analysis and in vitro bioassays. A set of 39

  14. Neutron activation analysis for chemical characterization of Brazilian oxo-biodegradable plastics

    International Nuclear Information System (INIS)

    Mateus Eugenio Boscaro; De Nadai Fernandes, E.A.; Marcio Arruda Bacchi; Luis Gustavo Cofani dos Santos; Cofani dos Santos, S.N.S.; Sandra Mara Martins-Franchetti

    2015-01-01

    The chemical characterization of oxo-biodegradable plastic bags was performed by neutron activation analysis. The presence of several chemical elements (As, Br, Ca, Co, Cr, Fe, Hf, K, La, Na, Sb, Sc, Ta and Zn) with large variability of mass fractions amongst samples indicates that these plastics receive additives and may have been contaminated during manufacturing process thereby becoming potential environmental pollutants. (author)

  15. Comprehensive Mass Analysis for Chemical Processes, a Case Study on L-Dopa Manufacture

    Science.gov (United States)

    To evaluate the “greenness” of chemical processes in route selection and process development, we propose a comprehensive mass analysis to inform the stakeholders from different fields. This is carried out by characterizing the mass intensity for each contributing chemical or wast...

  16. Development of international standards for surface analysis by ISO technical committee 201 on surface chemical analysis

    International Nuclear Information System (INIS)

    Powell, C.J.

    1999-01-01

    Full text: The International Organization for Standardization (ISO) established Technical Committee 201 on Surface Chemical Analysis in 1991 to develop documentary standards for surface analysis. ISO/TC 201 met first in 1992 and has met annually since. This committee now has eight subcommittees (Terminology, General Procedures, Data Management and Treatment, Depth Profiling, AES, SIMS, XPS, and Glow Discharge Spectroscopy (GDS)) and one working group (Total X-Ray Fluorescence Spectroscopy). Each subcommittee has one or more working groups to develop standards on particular topics. Australia has observer-member status on ISO/TC 201 and on all ISO/TC 201 subcommittees except GDS where it has participator-member status. I will outline the organization of ISO/TC 201 and summarize the standards that have been or are being developed. Copyright (1999) Australian X-ray Analytical Association Inc

  17. Chemical analysis of acoustically levitated drops by Raman spectroscopy.

    Science.gov (United States)

    Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

    2009-07-01

    An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension.

  18. Statistical analysis of DNT detection using chemically functionalized microcantilever arrays

    DEFF Research Database (Denmark)

    Bosco, Filippo; Bache, M.; Hwu, E.-T.

    2012-01-01

    The need for miniaturized and sensitive sensors for explosives detection is increasing in areas such as security and demining. Micrometer sized cantilevers are often used for label-free detection, and have previously been reported to be able to detect explosives. However, only a few measurements...... on the chemically treated surfaces results in significant bending of the cantilevers and in a decrease of their resonant frequencies. We present averaged measurements obtained from up to 72 cantilevers being simultaneously exposed to the same sample. Compared to integrated reference cantilevers with non...

  19. Integrated Process Design, Control and Analysis of Intensified Chemical Processes

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil

    chemical processes; for example, intensified processes such as reactive distillation. Most importantly, it identifies and eliminates potentially promising design alternatives that may have controllability problems later. To date, a number of methodologies have been proposed and applied on various problems......, that the same principles that apply to a binary non-reactive compound system are valid also for a binary-element or a multi-element system. Therefore, it is advantageous to employ the element based method for multicomponent reaction-separation systems. It is shown that the same design-control principles...

  20. Direct speciation analysis of arsenic in sub-cellular compartments using micro-X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Bacquart, Thomas; Deves, Guillaume; Ortega, Richard

    2010-01-01

    Identification of arsenic chemical species at a sub-cellular level is a key to understanding the mechanisms involved in arsenic toxicology and antitumor pharmacology. When performed with a microbeam, X-ray absorption near-edge structure (μ-XANES) enables the direct speciation analysis of arsenic in sub-cellular compartments avoiding cell fractionation and other preparation steps that might modify the chemical species. This methodology couples tracking of cellular organelles in a single cell by confocal or epifluorescence microscopy with local analysis of chemical species by μ-XANES. Here we report the results obtained with a μ-XANES experimental setup based on Kirkpatrick-Baez X-ray focusing optics that maintains high flux of incoming radiation (>10 11 ph/s) at micrometric spatial resolution (1.5x4.0 μm 2 ). This original experimental setup enabled the direct speciation analysis of arsenic in sub-cellular organelles with a 10 -15 g detection limit. μ-XANES shows that inorganic arsenite, As(OH) 3 , is the main form of arsenic in the cytosol, nucleus, and mitochondrial network of cultured cancer cells exposed to As 2 O 3 . On the other hand, a predominance of As(III) species is observed in HepG2 cells exposed to As(OH) 3 with, in some cases, oxidation to a pentavalent form in nuclear structures of HepG2 cells. The observation of intra-nuclear mixed redox states suggests an inter-individual variability in a cell population that can only be evidenced with direct sub-cellular speciation analysis.

  1. On the tracks of sandarac, review and chemical analysis.

    Science.gov (United States)

    Azémard, Clara; Ménager, Matthieu; Vieillescazes, Cathy

    2017-12-01

    The sandarac resin (Tetraclinis articulata) has been long used for its properties, mostly as a varnish component. Called juniper resin until the nineteenth century, the real botanical origin of sandarac is still unclear. The first approach to this issue is the review of the evolution of the etymology, terminology, and botanical description of sandarac through time. It seems that sandarac was mainly coming from T. articulata but the use of some juniper resins before the twentieth century is not to be excluded. The second approach is a chemical one; we used gas chromatography coupled to mass spectrometry to characterise the resin. As sandarac was the main component of the famous Italian varnish Vernice liquida, its characterisation is important for old paintings studies. However, although we could hope to differentiate sandarac, Juniperus communis and Juniperus oxycedrus resins by looking at their chemical composition, it appears that these resins are very similar. Besides, we notice a lack of old varnishes containing sandarac which complicates our work.

  2. Crystal-Chemical Analysis Martian Minerals in Gale Crater

    Science.gov (United States)

    Morrison, S. M.; Downs, R. T.; Blake, D. F.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Yen, A. S.; Chipera, S. J.; Treiman, A. H.; Vaniman, D. T.; hide

    2015-01-01

    The CheMin instrument on the Mars Science Laboratory rover Curiosity performed X-ray diffraction analyses on scooped soil at Rocknest and on drilled rock fines at Yellowknife Bay (John Klein and Cumberland samples), The Kimberley (Windjana sample), and Pahrump (Confidence Hills sample) in Gale crater, Mars. Samples were analyzed with the Rietveld method to determine the unit-cell parameters and abundance of each observed crystalline phase. Unit-cell parameters were used to estimate compositions of the major crystalline phases using crystal-chemical techniques. These phases include olivine, plagioclase and clinopyroxene minerals. Comparison of the CheMin sample unit-cell parameters with those in the literature provides an estimate of the chemical compositions of the major crystalline phases. Preliminary unit-cell parameters, abundances and compositions of crystalline phases found in Rocknest and Yellowknife Bay samples were reported in. Further instrument calibration, development of 2D-to- 1D pattern conversion corrections, and refinement of corrected data allows presentation of improved compositions for the above samples.

  3. Sensitivity analysis of critical experiment with direct perturbation compared to TSUNAMI-3D sensitivity analysis

    International Nuclear Information System (INIS)

    Barber, A. D.; Busch, R.

    2009-01-01

    The goal of this work is to obtain sensitivities from direct uncertainty analysis calculation and correlate those calculated values with the sensitivities produced from TSUNAMI-3D (Tools for Sensitivity and Uncertainty Analysis Methodology Implementation in Three Dimensions). A full sensitivity analysis is performed on a critical experiment to determine the overall uncertainty of the experiment. Small perturbation calculations are performed for all known uncertainties to obtain the total uncertainty of the experiment. The results from a critical experiment are only known as well as the geometric and material properties. The goal of this relationship is to simplify the uncertainty quantification process in assessing a critical experiment, while still considering all of the important parameters. (authors)

  4. A kinetic and equilibrium analysis of silicon carbide chemical vapor deposition on monofilaments

    Science.gov (United States)

    Gokoglu, S. A.; Kuczmarski, M. A.

    1993-01-01

    Chemical kinetics of atmospheric pressure silicon carbide (SiC) chemical vapor deposition (CVD) from dilute silane and propane source gases in hydrogen is numerically analyzed in a cylindrical upflow reactor designed for CVD on monofilaments. The chemical composition of the SiC deposit is assessed both from the calculated total fluxes of carbon and silicon and from chemical equilibrium considerations for the prevailing temperatures and species concentrations at and along the filament surface. The effects of gas and surface chemistry on the evolution of major gas phase species are considered in the analysis.

  5. Signed directed social network analysis applied to group conflict

    DEFF Research Database (Denmark)

    Zheng, Quan; Skillicorn, David; Walther, Olivier

    2015-01-01

    Real-world social networks contain relationships of multiple different types, but this richness is often ignored in graph-theoretic modelling. We show how two recently developed spectral embedding techniques, for directed graphs (relationships are asymmetric) and for signed graphs (relationships...... are both positive and negative), can be combined. This combination is particularly appropriate for intelligence, terrorism, and law enforcement applications. We illustrate by applying the novel embedding technique to datasets describing conflict in North-West Africa, and show how unusual interactions can...

  6. Laser Applications to Chemical, Security, and Environmental Analysis: introduction to the feature issue

    International Nuclear Information System (INIS)

    Dreizler, Andreas; Fried, Alan; Gord, James R.

    2007-01-01

    This Applied Optics feature issue on Laser Applications to Chemical, Security,and Environmental Analysis (LACSEA) highlights papers presented at theLACSEA 2006 Tenth Topical Meeting sponsored by the Optical Society ofAmerica

  7. Laser applications to chemical, security, and environmental analysis: introduction to the feature issue.

    Science.gov (United States)

    Seeger, Thomas; Dreier, Thomas; Chen, Weidong; Kearny, Sean; Kulatilaka, Waruna

    2017-04-10

    This Applied Optics feature issue on laser applications to chemical, security, and environmental analysis (LACSEA) highlights papers presented at the LACSEA 2016 Fifteenth Topical Meeting sponsored by the Optical Society of America.

  8. DRES Database of Methods for the Analysis of Chemical Warfare Agents

    National Research Council Canada - National Science Library

    D'Agostino, Paul

    1997-01-01

    .... Update of the database continues as an ongoing effort and the DRES Database of Methods for the Analysis of Chemical Warfare Agents is available panel in hardcopy form or as a softcopy Procite or Wordperfect file...

  9. Chemical risk evaluation, importance of the risk analysis framework uses: Latin America development restrictions

    International Nuclear Information System (INIS)

    Carrillo, M.

    2013-01-01

    The power point presentation is about reach and results of the risk analysis in Venezuela, chemical dangers in food, human damage, injuries , technologies news in fodd development, toxicity, microbiological risk, technical recommendations

  10. Environmental Impact Assessment for Socio-Economic Analysis of Chemicals

    DEFF Research Database (Denmark)

    Calow, Peter; Biddinger, G; Hennes, C

    This report describes the requirements for, and illustrates the application of, a methodology for a socio-economic analysis (SEA) especially as it might be adopted in the framework of REACH.......This report describes the requirements for, and illustrates the application of, a methodology for a socio-economic analysis (SEA) especially as it might be adopted in the framework of REACH....

  11. [Content analysis of websites directed to low back pain].

    Science.gov (United States)

    Gülcü, Nebahat; Bulut, Sefa

    2010-04-01

    In this study, we aimed to evaluate the websites directed at providing information about low back pain with respect to their content and quality. The websites were detected by scanning the words 'low back pain' from the Turkish pages module of the Google search portal. One hundred and fifty websites introduced on the first 20 pages were evaluated; the 65 websites determined to fulfill the desired criteria were analyzed in detail. Twenty of the 65 websites were excluded due to low quality, extraction from another website, sales promotion-related books/products, or qualified as news. In the majority of websites, no site administrator was indicated. When an administrator was indicated, the common specialities were physical therapists (13%), neurosurgeons (8%) and anesthesiologists (4%). Ten of the websites (22%) provided a pain definition close to international standards, whereas pain classification was available on most of the websites (84%). There was no mention of methods of pain scoring on any of them. Treatment modalities for which information was given included mostly behavioral, physical and pharmacological therapies, respectively. Complementary techniques, in order, included acupuncture, yoga and bioenergy. On 10 websites, text was supported with medical photographs, and videos were available on two. None of the websites had a provision for selection of other languages. Websites directed to low back pain should be enriched with respect to scientific content, thereby serving to increase the level of social education related to pain management.

  12. Performance analysis and evaluation of direct phase measuring deflectometry

    Science.gov (United States)

    Zhao, Ping; Gao, Nan; Zhang, Zonghua; Gao, Feng; Jiang, Xiangqian

    2018-04-01

    Three-dimensional (3D) shape measurement of specular objects plays an important role in intelligent manufacturing applications. Phase measuring deflectometry (PMD)-based methods are widely used to obtain the 3D shapes of specular surfaces because they offer the advantages of a large dynamic range, high measurement accuracy, full-field and noncontact operation, and automatic data processing. To enable measurement of specular objects with discontinuous and/or isolated surfaces, a direct PMD (DPMD) method has been developed to build a direct relationship between phase and depth. In this paper, a new virtual measurement system is presented and is used to optimize the system parameters and evaluate the system's performance in DPMD applications. Four system parameters are analyzed to obtain accurate measurement results. Experiments are performed using simulated and actual data and the results confirm the effects of these four parameters on the measurement results. Researchers can therefore select suitable system parameters for actual DPMD (including PMD) measurement systems to obtain the 3D shapes of specular objects with high accuracy.

  13. Engineering and Functional Analysis of Mitotic Kinases Through Chemical Genetics.

    Science.gov (United States)

    Jones, Mathew J K; Jallepalli, Prasad V

    2016-01-01

    During mitosis, multiple protein kinases transform the cytoskeleton and chromosomes into new and highly dynamic structures that mediate the faithful transmission of genetic information and cell division. However, the large number and strong conservation of mammalian kinases in general pose significant obstacles to interrogating them with small molecules, due to the difficulty in identifying and validating those which are truly selective. To overcome this problem, a steric complementation strategy has been developed, in which a bulky "gatekeeper" residue within the active site of the kinase of interest is replaced with a smaller amino acid, such as glycine or alanine. The enlarged catalytic pocket can then be targeted in an allele-specific manner with bulky purine analogs. This strategy provides a general framework for dissecting kinase function with high selectivity, rapid kinetics, and reversibility. In this chapter we discuss the principles and techniques needed to implement this chemical genetic approach in mammalian cells.

  14. CFD analysis of hypersonic, chemically reacting flow fields

    Science.gov (United States)

    Edwards, T. A.

    1993-01-01

    Design studies are underway for a variety of hypersonic flight vehicles. The National Aero-Space Plane will provide a reusable, single-stage-to-orbit capability for routine access to low earth orbit. Flight-capable satellites will dip into the atmosphere to maneuver to new orbits, while planetary probes will decelerate at their destination by atmospheric aerobraking. To supplement limited experimental capabilities in the hypersonic regime, computational fluid dynamics (CFD) is being used to analyze the flow about these configurations. The governing equations include fluid dynamic as well as chemical species equations, which are being solved with new, robust numerical algorithms. Examples of CFD applications to hypersonic vehicles suggest an important role this technology will play in the development of future aerospace systems. The computational resources needed to obtain solutions are large, but solution adaptive grids, convergence acceleration, and parallel processing may make run times manageable.

  15. Chemical Fingerprint Analysis and Quantitative Analysis of Rosa rugosa by UPLC-DAD

    Directory of Open Access Journals (Sweden)

    Sanawar Mansur

    2016-12-01

    Full Text Available A method based on ultra performance liquid chromatography with a diode array detector (UPLC-DAD was developed for quantitative analysis of five active compounds and chemical fingerprint analysis of Rosa rugosa. Ten batches of R. rugosa collected from different plantations in the Xinjiang region of China were used to establish the fingerprint. The feasibility and advantages of the used UPLC fingerprint were verified for its similarity evaluation by systematically comparing chromatograms with professional analytical software recommended by State Food and Drug Administration (SFDA of China. In quantitative analysis, the five compounds showed good regression (R2 = 0.9995 within the test ranges, and the recovery of the method was in the range of 94.2%–103.8%. The similarities of liquid chromatography fingerprints of 10 batches of R. rugosa were more than 0.981. The developed UPLC fingerprint method is simple, reliable, and validated for the quality control and identification of R. rugosa. Additionally, simultaneous quantification of five major bioactive ingredients in the R. rugosa samples was conducted to interpret the consistency of the quality test. The results indicated that the UPLC fingerprint, as a characteristic distinguishing method combining similarity evaluation and quantification analysis, can be successfully used to assess the quality and to identify the authenticity of R. rugosa.

  16. ANALYSIS AND IDENTIFICATION SPIKING CHEMICAL COMPOUNDS RELATED TO CHEMICAL WEAPON CONVENTION IN UNKNOWN WATER SAMPLES USING GAS CHROMATOGRAPHY AND GAS CHROMATOGRAPHY ELECTRON IONIZATION MASS SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    Harry Budiman

    2010-06-01

    Full Text Available The identification and analysis of chemical warfare agents and their degradation products is one of important component for the implementation of the convention. Nowadays, the analytical method for determination chemical warfare agent and their degradation products has been developing and improving. In order to get the sufficient analytical data as recommended by OPCW especially in Proficiency Testing, the spiking chemical compounds related to Chemical Weapon Convention in unknown water sample were determined using two different techniques such as gas chromatography and gas chromatography electron-impact ionization mass spectrometry. Neutral organic extraction, pH 11 organic extraction, cation exchanged-methylation, triethylamine/methanol-silylation were performed to extract the chemical warfare agents from the sample, before analyzing with gas chromatography. The identification of chemical warfare agents was carried out by comparing the mass spectrum of chemicals with mass spectrum reference from the OPCW Central Analytical Database (OCAD library while the retention indices calculation obtained from gas chromatography analysis was used to get the confirmation and supported data of  the chemical warfare agents. Diisopropyl methylphosphonate, 2,2-diphenyl-2-hydroacetic acid and 3-quinuclidinol were found in unknown water sample. Those chemicals were classified in schedule 2 as precursor or reactant of chemical weapons compound in schedule list of Chemical Weapon Convention.   Keywords: gas chromatography, mass spectrometry, retention indices, OCAD library, chemical warfare agents

  17. Research Directions for Cyber Experimentation: Workshop Discussion Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    DeWaard, Elizabeth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Deccio, Casey [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fritz, David Jakob [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tarman, Thomas D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    Sandia National Laboratories hosted a workshop on August 11, 2017 entitled "Research Directions for Cyber Experimentation," which focused on identifying and addressing research gaps within the field of cyber experimentation , particularly emulation testbeds . This report mainly documents the discussion toward the end of the workshop, which included research gaps such as developing a sustainable research infrastructure, exp anding cyber experimentation, and making the field more accessible to subject matter experts who may not have a background in computer science . Other gaps include methodologies for rigorous experimentation, validation, and uncertainty quantification, which , if addressed, also have the potential to bridge the gap between cyber experimentation and cyber engineering. Workshop attendees presented various ways to overcome these research gaps, however the main conclusion for overcoming these gaps is better commun ication through increased workshops, conferences, email lists, and slack chann els, among other opportunities.

  18. Direct analysis of thymic function in children with Down's syndrome

    Directory of Open Access Journals (Sweden)

    Meschiari Liviana

    2005-02-01

    Full Text Available Abstract Background Down's syndrome (DS is characterized by several immunological defects, especially regarding T cell compartment. DS is considered the best example of accelerated ageing in humans. Direct observations of the thymus have shown that in DS this organ undergoes severe histological and morphological changes. However, no data on its capacity to generate T cells are present in the literature. Here, using a new technology based upon real time PCR, we have investigated the capacity of the thymus to produce and release newly generated T lymphocytes (the so called "recent thymic emigrants", RTE in children with DS. Methods We studied 8 children affected by DS, aged 2–7 years, compared with 8 age- and sex-matched healthy controls. Flow cytometry was used to determine different lymphocytes subsets. Real time PCR with the Taqman system was used to quantify the amount of RTE, i.e. peripheral blood lymphocytes that express the T cell receptor rearrangement excision circles (TREC. Results In comparison with control children, those with DS had a significant lower number of TREC+ peripheral blood cells. Moreover, in DS children but not in controls, a strong negative correlation between age and the levels of TREC+ cells was found. Conclusions The direct measure of thymic output indicates that the impairment of the organ results in a reduced production of newly generated T cells. This observation could suggest that cytokines able to modulate thymic function, such as interleukins, could be useful to improve the functionality of the organ and to treat the immunodeficiency present in DS subjects.

  19. Quantum chemical analysis of potential anti-Parkinson agents

    Indian Academy of Sciences (India)

    Intermolecular binding energy components could not be analyzed by docking and due to this .... Cluster analysis was performed on the docked results with regard to RMS ... gard, docking simulation is a key tool in structural mo- lecular biology ...

  20. Sampling and chemical analysis by TXRF of size-fractionated ambient aerosols and emissions

    International Nuclear Information System (INIS)

    John, A.C.; Kuhlbusch, T.A.J.; Fissan, H.; Schmidt, K.-G-; Schmidt, F.; Pfeffer, H.-U.; Gladtke, D.

    2000-01-01

    Results of recent epidemiological studies led to new European air quality standards which require the monitoring of particles with aerodynamic diameters ≤ 10 μm (PM 10) and ≤ 2.5 μm (PM 2.5) instead of TSP (total suspended particulate matter). As these ambient air limit values will be exceeded most likely at several locations in Europe, so-called 'action plans' have to be set up to reduce particle concentrations, which requires information about sources and processes of PMx aerosols. For chemical characterization of the aerosols, different samplers were used and total reflection x-ray fluorescence analysis (TXRF) was applied beside other methods (elemental and organic carbon analysis, ion chromatography, atomic absorption spectrometry). For TXRF analysis, a specially designed sampling unit was built where the particle size classes 10-2.5 μm and 2.5-1.0 μm were directly impacted on TXRF sample carriers. An electrostatic precipitator (ESP) was used as a back-up filter to collect particles <1 μm directly on a TXRF sample carrier. The sampling unit was calibrated in the laboratory and then used for field measurements to determine the elemental composition of the mentioned particle size fractions. One of the field campaigns was carried out at a measurement site in Duesseldorf, Germany, in November 1999. As the composition of the ambient aerosols may have been influenced by a large construction site directly in the vicinity of the station during the field campaign, not only the aerosol particles, but also construction material was sampled and analyzed by TXRF. As air quality is affected by natural and anthropogenic sources, the emissions of particles ≤ 10 μm and ≤ 2.5 μm, respectively, have to be determined to estimate their contributions to the so called coarse and fine particle modes of ambient air. Therefore, an in-stack particle sampling system was developed according to the new ambient air quality standards. This PM 10/PM 2.5 cascade impactor was

  1. Growth of ZnO nanowire arrays directly onto Si via substrate topographical adjustments using both wet chemical and dry etching methods

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Nathan A., E-mail: 523615@swansea.ac.uk [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom); Evans, Jon E.; Jones, Daniel R. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Lord, Alex M. [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Wilks, S.P. [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom)

    2015-03-15

    Highlights: • Arrays of catalyst-free ZnO NWs have been grown by CVD without seed layers on Si. • Si surface topography was altered by substrate etching, resulting in NW growth. • XPS analysis shows growth is related to topography and not surface contamination. • Using e-beam lithography with etching, selective nanowire growth is demonstrated. • Electrical measurements on the arrays show improved conduction through the Si. - Abstract: Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

  2. Titanium dioxide nanoparticles: synthesis, X-Ray line analysis and chemical composition study

    Energy Technology Data Exchange (ETDEWEB)

    Chenari, Hossein Mahmoudi, E-mail: mahmoudi_hossein@guilan.ac.ir, E-mail: h.mahmoudiph@gmail.com [University of Guilan, Rasht (Iran, Islamic Republic of); Seibel, Christoph; Hauschild, Dirk; Reinert, Friedrich [Karlsruhe Institute of Technology - KIT, Gemeinschaftslabor für Nanoanalytik, Karlsruhe (Germany); Abdollahian, Hossein [Nanotechnology Research Center of Urmia University, Urmia, (Iran, Islamic Republic of)

    2016-11-15

    TiO{sub 2} nanoparticles have been synthesized by the sol-gel method using titanium alkoxide and isopropanol as a precursor. The structural properties and chemical composition of the TiO{sub 2} nanoparticles were studied using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy.The X-ray powder diffraction pattern confirms that the particles are mainly composed of the anatase phase with the preferential orientation along [101] direction. The physical parameters such as strain, stress and energy density were investigated from the Williamson- Hall (W-H) plot assuming a uniform deformation model (UDM), and uniform deformation energy density model (UDEDM). The W-H analysis shows an anisotropic nature of the strain in nano powders. The scanning electron microscopy image shows clear TiO{sub 2} nanoparticles with particle sizes varying from 60 to 80nm. The results of mean particle size of TiO{sub 2} nanoparticles show an inter correlation with the W-H analysis and SEM results. Our X-ray photoelectron spectroscopy spectra show that nearly a complete amount of titanium has reacted to TiO{sub 2}. (author)

  3. Chemical analysis of useful trace elements in sea water

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Fujii, Ayako; Miyai, Yoshitaka; Sakane, Kohji; Ogata, Noboru.

    1983-01-01

    The methods for the analysis of useful trace elements in sea water which have been tried so far are reviewed, and these methods are described briefly from the standpoint of studying the collection of resources. Ag and Au can be determined by concentrating sea water by ion-exchange method, solvent extraction method and electrodeposition method, then the elements are measured quantitatively by activation analysis and atomic absorption spectrochemical analysis. Sr, B and Li, which exist in relatively high concentration in sea water, are determined easily by atomic absorption spectrochemical analysis and absorption spectrometry. U, Mo and V are measured suitably by concentrating the elements by coprecipitation or solvent extraction method, and measuring by fluorescence analysis and arsenazo-3 method for U and through graphite-atomic absorption analysis for Mo and V. It has been revealed that the concentration of Ag and Au in sea water is extremely low, accordingly the recovery study is not conducted recently. On the other hand, the adsorption method using hydrated titanium oxide and amidoxim adsorbents for U, Mo and V, the adsorption method using aluminum adsorbent for Li, and the adsorption method using magnesium oxide and zirconium hydroxide and the solvent extraction method for B are hopeful to recover these elements. (Yoshitake, I.)

  4. Imaging analysis of direct alanine uptake by rice seedlings

    International Nuclear Information System (INIS)

    Nihei, Naoto; Masuda, Sayaka; Rai, Hiroki; Nakanishi, Tomoko M.

    2008-01-01

    We presented alanine, a kind of amino acids, uptake by a rice seedling to study the basic mechanism of the organic fertilizer effectiveness in organic farming. The rice grown in the culture solution containing alanine as a nitrogen source absorbed alanine approximately two times faster than that grown with NH 4 + from analysis of 14 C-alanine images by Imaging Plate method. It was suggested that the active transport ability of the rice seeding was induced in roots by existence of alanine in the rhizosphere. The alanine uptake images of the rice roots were acquired every 5 minutes successively by the real-time autoradiography system we developed. The analysis of the successive images showed that alanine uptake was not uniform throughout the root but especially active at the root tip. (author)

  5. Managing Security Risks in an Industrial Investment – Analysis Directions

    Directory of Open Access Journals (Sweden)

    Stefan Dragomir

    2016-05-01

    Full Text Available This paper achieved an analysis of some important management strategies for an investment, in correlation with index of global pollution. Environmental security assessment shall be determined taking into account the workplace security and effects on health, safety of workers in an industry investment. It is necessary to observe and collect a larger number of data generated by the development of an industrial process, so as to make a deep analysis on global pollution index and how it is affected industrial investment environment. This research shows how can the substances that infest the environment to produce much damage and influence the environmental factors (air, water, soil, landscape, fauna and flora. When we know the risks that characterize the plant equipment, we can protect the life and we can protect the environment for a sustainable development in the future.

  6. Pooled Calibrations and Retainment of Outliers Improved Chemical Analysis

    DEFF Research Database (Denmark)

    Andersen, Jens; Sattar Hassan Alfaloje, Haedar

    2013-01-01

    . The results indicate t hat the procedures outlined in the Eurachem/CITAC Guide are of tremendous value to analytical sciences because they direct researcher’s attention towards the concept of consensus values rather than tow ards true values. Introduction of certified reference materials (CRM’s) in metrology...... has provided much new information on working habits in professiona l laboratories and CRM’s may be applied to establish the true level of uncertainty for a given type of ana lytical method. Finally, it is proposed to devise a new procedure of method val idation that facilitates QA in general, thus...

  7. Pooled calibrations and retainment of outliers improve chemical analysis

    DEFF Research Database (Denmark)

    Andersen, Jens; Alfaloje, Haedar S.H.

    2012-01-01

    indicate that the procedures outlined in the Eurachem/CITAC Guide are of tremendous value to analytical sciences because they direct researcher's attention towards the concept of consensus values rather than towards true values. Introduction of certified reference materials (CRM’s) in metrology has...... provided much new information on working habits in professional laboratories and CRM’s may be applied to establish the true level of uncertainty for a given type of analytical method. Finally, it is proposed to devise a new procedure of method validation that facilitates QA in general, thus saving many...

  8. Directed Self-Assembly of Triblock Copolymer on Chemical Patterns for Sub-10-nm Nanofabrication via Solvent Annealing.

    Science.gov (United States)

    Xiong, Shisheng; Wan, Lei; Ishida, Yoshihito; Chapuis, Yves-Andre; Craig, Gordon S W; Ruiz, Ricardo; Nealey, Paul F

    2016-08-23

    Directed self-assembly (DSA) of block copolymers (BCPs) is a leading strategy to pattern at sublithographic resolution in the technology roadmap for semiconductors and is the only known solution to fabricate nanoimprint templates for the production of bit pattern media. While great progress has been made to implement block copolymer lithography with features in the range of 10-20 nm, patterning solutions below 10 nm are still not mature. Many BCP systems self-assemble at this length scale, but challenges remain in simultaneously tuning the interfacial energy atop the film to control the orientation of BCP domains, designing materials, templates, and processes for ultra-high-density DSA, and establishing a robust pattern transfer strategy. Among the various solutions to achieve domains that are perpendicular to the substrate, solvent annealing is advantageous because it is a versatile method that can be applied to a diversity of materials. Here we report a DSA process based on chemical contrast templates and solvent annealing to fabricate 8 nm features on a 16 nm pitch. To make this possible, a number of innovations were brought in concert with a common platform: (1) assembling the BCP in the phase-separated, solvated state, (2) identifying a larger process window for solvated triblock vs diblock BCPs as a function of solvent volume fraction, (3) employing templates for sub-10-nm BCP systems accessible by lithography, and (4) integrating a robust pattern transfer strategy by vapor infiltration of organometallic precursors for selective metal oxide synthesis to prepare an inorganic hard mask.

  9. Chemical Quality Status of Rivers for the Water Framework Directive: A Case Study of Toxic Metals in North West England

    Directory of Open Access Journals (Sweden)

    Colin Neal

    2011-06-01

    Full Text Available This paper provides data from two years of monitoring of the chemical quality of rivers and streams in North West England from the clean headwaters to polluted rivers just above the tidal reach and covers 26 sites including the Ribble, Wyre and the tributary rivers of the Calder and Douglas. Across the basins that include areas of rural, urban and industrial typologies, data is presented for three of the priority substances in the Water Framework Directive i.e., nickel (Ni, cadmium (Cd, and lead (Pb. Average concentrations are low and well below the Environmental Quality Standards values for all three of these substances. Cadmium and Pb appear in approximately equal proportions in the dissolved (0.45 µm whilst Ni occurs predominantly in the dissolved form (92%. Regional inputs of these metals arise mostly from diffuse sources as the storm-flow concentrations are generally greater than at base-flow condition. Greater concentrations of Ni are transported at the headwaters and smaller tributary sites under storm flow condition than for the main stream of the Ribble. For Ni, amounts increase as the river proceeds from its headwaters down towards the Ribble and Wyre estuaries, whilst Cd and Pb show consistent values throughout the catchment. There is annual cycling of dissolved concentrations of Cd, Pb and Ni for the clean headwater streams that gives maxima during the latter half of the year when the river flow is greater. For the impacted sites the pattern is less distinct or absent. Our estimates suggest that the Ribble estuary receives 550 t y−1 of dissolved Ni, 16 t y−1 of dissolved Cd and 240 t y−1 of dissolved Pb.

  10. Quantum analysis of the direct measurement of light waves

    International Nuclear Information System (INIS)

    Saldanha, Pablo L

    2014-01-01

    In a beautiful experiment performed about a decade ago, Goulielmakis et al (2004 Science 305 1267–69) made a direct measurement of the electric field of light waves. However, they used a laser source to produce the light field, whose quantum state has a null expectation value for the electric field operator, so how was it possible to measure this electric field? Here we present a quantum treatment for the f:2f interferometer used to calibrate the carrier–envelope phase of the light pulses in the experiment. We show how the special nonlinear features of the f:2f interferometer can change the quantum state of the electromagnetic field inside the laser cavity to a state with a definite oscillating electric field, explaining how the ‘classical’ electromagnetic field emerges in the experiment. We discuss that this experiment was, to our knowledge, the first demonstration of an absolute coherent superposition of different photon number states in the optical regime. (paper)

  11. Sampling and chemical analysis of urban street runoff

    International Nuclear Information System (INIS)

    Daub, J.; Striebel, T.; Robien, A.; Herrmann, R.

    1993-01-01

    In order to characterize the environmentally relevant physical and chemical properties of urban street runoff, an automatic sampling device was developed. Precipitation samples were collected together with runoff samples. Organic and inorganic compounds were analysed in the runoff. Dissolved and particle bound substances were analysed separately. The concentrations in runoff are generally considerably higher than in precipitation. Concentrations of lead, fluoranthene and benzo(a)pyrene, in particular are higher in runoffs at sites with high traffic densities than at sites with low traffic densities. Preceding dry period normally has no effect on the measured concentrations. The typical chemograph of a dissolved substance shows a maximum at the beginning of the event dropping quickly to a minimum, which often coincides with the maximum in runoff rate. A slight rise is observed with decreasing runoff rates at the end of the event. Applying a mathematical model, chemographs may be described by three terms: - Relatively large amounts of easily soluble material at the beginning of the event decrease with increasing runoff. Conservative behaviour is assumed. - A part which varies inversely to the runoff rate. This term assumes zero-order kinetics; the amount dissolved from surfaces is constant with time. - A small constant term. Concentrations of particle bound substances correlate with amounts of total suspended solids. Frequently a negative correlation between the specific concentration of substances and the concentration of total suspended solids is observed. (orig.) [de

  12. Comprehensive Analysis Competence and Innovative Approaches for Sustainable Chemical Production.

    Science.gov (United States)

    Appel, Joerg; Colombo, Corrado; Dätwyler, Urs; Chen, Yun; Kerimoglu, Nimet

    2016-01-01

    Humanity currently sees itself facing enormous economic, ecological, and social challenges. Sustainable products and production in specialty chemistry are an important strategic element to address these megatrends. In addition to that, digitalization and global connectivity will create new opportunities for the industry. One aspect is examined in this paper, which shows the development of comprehensive analysis of production networks for a more sustainable production in which the need for innovative solutions arises. Examples from data analysis, advanced process control and automated performance monitoring are shown. These efforts have significant impact on improved yields, reduced energy and water consumption, and better product performance in the application of the products.

  13. Environmental Risk Assessment: Spatial Analysis of Chemical Hazards and Risks in South Korea

    Science.gov (United States)

    Yu, H.; Heo, S.; Kim, M.; Lee, W. K.; Jong-Ryeul, S.

    2017-12-01

    This study identified chemical hazard and risk levels in Korea by analyzing the spatial distribution of chemical factories and accidents. The number of chemical factories and accidents in 5-km2 grids were used as the attribute value for spatial analysis. First, semi-variograms were conducted to examine spatial distribution patterns and to identify spatial autocorrelation of chemical factories and accidents. Semi-variograms explained that the spatial distribution of chemical factories and accidents were spatially autocorrelated. Second, the results of the semi-variograms were used in Ordinary Kriging to estimate chemical hazard and risk level. The level values were extracted from the Ordinary Kriging result and their spatial similarity was examined by juxtaposing the two values with respect to their location. Six peaks were identified in both the hazard and risk estimation result, and the peaks correlated with major cities in Korea. Third, the estimated hazard and risk levels were classified with geometrical interval and could be classified into four quadrants: Low Hazard and Low Risk (LHLR), Low Hazard and High Risk (LHHR), High Hazard and Low Risk (HHLR), and High Hazard and High Risk (HHHR). The 4 groups identified different chemical safety management issues in Korea; relatively safe LHLR group, many chemical reseller factories were found in HHLR group, chemical transportation accidents were in the LHHR group, and an abundance of factories and accidents were in the HHHR group. Each quadrant represented different safety management obstacles in Korea, and studying spatial differences can support the establishment of an efficient risk management plan.

  14. Controlling organic chemical hazards in food manufacturing: a hazard analysis critical control points (HACCP) approach.

    Science.gov (United States)

    Ropkins, K; Beck, A J

    2002-08-01

    Hazard analysis by critical control points (HACCP) is a systematic approach to the identification, assessment and control of hazards. Effective HACCP requires the consideration of all hazards, i.e., chemical, microbiological and physical. However, to-date most 'in-place' HACCP procedures have tended to focus on the control of microbiological and physical food hazards. In general, the chemical component of HACCP procedures is either ignored or limited to applied chemicals, e.g., food additives and pesticides. In this paper we discuss the application of HACCP to a broader range of chemical hazards, using organic chemical contaminants as examples, and the problems that are likely to arise in the food manufacturing sector. Chemical HACCP procedures are likely to result in many of the advantages previously identified for microbiological HACCP procedures: more effective, efficient and economical than conventional end-point-testing methods. However, the high costs of analytical monitoring of chemical contaminants and a limited understanding of formulation and process optimisation as means of controlling chemical contamination of foods are likely to prevent chemical HACCP becoming as effective as microbiological HACCP.

  15. The application of atomic absorption spectrometry to chemical analysis

    International Nuclear Information System (INIS)

    Walsh, A.

    1980-01-01

    YhThe history of the development of atomic absorption methods of elemental analysis is outlined. The theoretical basis of atomic absorption methods is discussed and the principle of modern methods of atomic absorption measurements is described. The advantages, scope and limations of these methods are discussed. Related methods based on the measurement of atomic fluorescence are also described

  16. Chemical Analysis of Asymptotic Giant Branch Stars in M62

    NARCIS (Netherlands)

    Lapenna, E.; Mucciarelli, A.; Ferraro, F. R.; Origlia, L.; Lanzoni, B.; Massari, D.; Dalessandro, E.

    2015-01-01

    We have collected UVES-FLAMES high-resolution spectra for a sample of 6 asymptotic giant branch (AGB) and 13 red giant branch (RGB) stars in the Galactic globular cluster (GC) M62 (NGC 6266). Here we present the detailed abundance analysis of iron, titanium, and light elements (O, Na, Mg, and Al).

  17. The Impact of Flow Injection on Modern Chemical Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    and preconcentration procedures. In recent years, FIA has been supplemented by Sequential Injection Analysis (SIA) and the Lab-on-Valve (LOV) approach. Following a brief historic introduction and an account of the impact of FIA in academia, the lecture will describe these two new generations of FIA, accompanied...

  18. Different materials for direct pulp capping: systematic review and meta-analysis and trial sequential analysis.

    Science.gov (United States)

    Schwendicke, Falk; Brouwer, Fredrik; Schwendicke, Anja; Paris, Sebastian

    2016-07-01

    We systematically assessed randomized controlled trials comparing direct pulp capping materials. Trials comparing materials for direct capping and evaluating clinically and/or radiographically determined success after minimum 3 months were included. Two reviewers independently screened electronic databases (Medline, Central, Embase) and performed hand searches. Risk of bias was assessed and meta-analyses were performed, separated for dentition. Trial sequential analysis was used to assess risk of random errors. Strength of evidence was graded using the GRADE approach. From a total of 453 identified studies, 11 (all with high risk of bias) investigating 1094 teeth (922 patients) were included. Six studies were on primary teeth (all with carious exposures) and five on permanent teeth (carious and artificial exposures). Mean follow-up was 14 months (range 3-24). Most studies used calcium hydroxide as control, comparing it to mineral trioxide aggregate (MTA) (three studies), bonding without prior etching/conditioning (two), or bonding with prior etching/conditioning, enamel matrix proteins, resin-modified glass ionomer cement, calcium sulfate, zinc oxide eugenol, corticosteroids, antibiotics, or formocresol (each in only one study). One study compared MTA and calcium-enriched cement. In permanent teeth, risk of failure was significantly decreased if MTA instead of calcium hydroxide was used (risk ratio (RR) [95 % confidence intervals (CI)] 0.59 [0.39/0.90]); no difference was found for primary teeth. Other comparisons did not find significant differences or were supported by only one study. No firm evidence was reached according to trial sequential analysis. There is insufficient data to recommend or refute the use of a specific material. More long-term practice-based studies with real-life exposures are required. To reduce risk of failure, dentists might consider using MTA instead of calcium hydroxide (CH) for direct capping. Current evidence is insufficient for

  19. ANALYSIS OF FOREIGN DIRECT INVESTMENTS ENGAGED BY JAPANESE MULTINATIONAL COMPANIES

    Directory of Open Access Journals (Sweden)

    CODRUŢA DURA

    2011-01-01

    Full Text Available In recent years, the most visible feature of globalization was the new trend of the capital flow which moves from the stage of nternalization to the stage of transnationalization. The decisive factor that led to this development was the trans-nationalization of production/ distribution networks by multinational companies (MNCs. MNCs, which are also frequently referred to as transnational corporations (TNCs, are conglomerate organizations which carry out multiple and diverse economic activities and they consists of a parent company and a large number of subsidiaries operating in various countries of the world. Japan has been worthy of note on the international business scene not only by the high competitiveness of its companies on the global markets, but especially through the transnationalization of the activities of these enterprises, a process which has resulted in the implementation, via Foreign Direct Investments (FDI of Japanese production units abroad, with significant positive impact both on the global economy and on the domestic economy. A great number of empirical studies since the mid-1990s, using firm-level data, have shown that multinational companies (MNCs dominate today the Japanese business environment. The paper puts together the findings of some interesting working papers published by Japanese researchers in recent years, trying to provide a scientific answer to the following question: “In what way do FDI undertaken by MNCs influence the level of performances achieved by Japanese companies at home?” The conclusion is that FDI and the activity carried out by Japanese MNCs abroad have indubitable positive effects on both countries and firms involved - such as raises in production, employment and productivity at firms’ level or increases in competition intensity among firms, improvements in real wage and welfare at macroeconomic level.

  20. Theoretically exploring direct and indirect chemical effects across ecological and exposure scenarios using mechanistic fate and effects modelling

    NARCIS (Netherlands)

    Laender, de F.; Morselli, M.; Baveco, H.; Brink, van den P.J.; Guardo, Di A.

    2015-01-01

    Predicting ecosystem response to chemicals is a complex problem in ecotoxicology and a challenge for risk assessors. The variables potentially influencing chemical fate and exposure define the exposure scenario while the variables determining effects at the ecosystem level define the ecological

  1. Continuous-flow centrifugation to collect suspended sediment for chemical analysis

    Science.gov (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

    2016-12-22

    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  2. Archaeological and chemical analysis of Tell el Yahudiyeh ware

    International Nuclear Information System (INIS)

    Kaplan, M.F.; Harbottle, G.; Sayre, E.V.

    1978-01-01

    Typological and geographic analyses indicate that Tell el Yahudiyeh ware (found in Cyprus, Egypt, Nubia, and the Levant during the Middle Bronze period, c. 1750-1550 B.C.) were probably manufactured in two areas, the Nile Valley and the Levant. Activation analysis was carried out and correlated with the archaeological analyses. Results confirm the two ''families'' of the ware, one Egyptian and one Levantine. Speculations are offered on the social interaction of the period. 11 figures, 2 tables

  3. Variability of chemical analysis of reinforcing bar produced in Saudi Arabia

    Science.gov (United States)

    Salman, A.; Djavanroodi, F.

    2018-04-01

    In view of the importance and demanding roles of steel rebar’s in the reinforced concrete structures, accurate information on the properties of the steels is important at the design stage. In the steelmaking process, production variations in chemical composition are unavoidable. The aim of this work is to study the variability of the chemical composition of reinforcing steel produced throughout the Saudi Arabia and asses the quality of steel rebar’s acoording to ASTM A615. 68 samples of ASTM A615 Grade 60 from different manufacturers were collected and tested using the Spectrometer test to obtain Chemical Compositions. EasyFit (5.6) software is utilized to conducted statistical analysis. Chemical compositions distributions and, control charts are generated for the compositions. Results showed that some compositions are above the upper line of the control chart. Finally, the analyses show that less than 3% of the steel failed to meet minimum ASTM standards for chemical composition.

  4. Separate direct injection of diesel and ethanol: A numerical analysis

    Directory of Open Access Journals (Sweden)

    Burnete Nicolae V.

    2017-01-01

    Full Text Available The purpose of this study is to investigate the theoretical possibility of using a pilot diesel injection for the auto-ignition of a main ethanol injection in a compression ignition engine. To this effect a predictive simulation model has been built based on experimental results for a diesel cycle (pilot and main injection at 1500 and 2500 min–1, respectively. For every engine speed, in addition to the diesel reference cycle, two more simulations were done: one with the same amount of fuel injected into the cylinder and one with the same amount of energy, which required an increase in the quantity of ethanol proportional to the ratio of its lower heating value and that of diesel. The simulations showed that in all cases the pilot diesel led to the auto-ignition of ethanol. The analysis of the in-cylinder traces at 1500 min–1 showed that combustion efficiency is improved, the peak temperature value decrease with approximately 240 K and, as a result, the NO emissions are 3.5-4 times lower. The CO and CO2 values depend on the amount of fuel injected into the cylinder. At 2500 min–1 there are similar trends but with the following observations: the ignition delay increases, while the pressure and temperature are lower.

  5. Physical, chemical and microbial analysis of bottled drinking water.

    Science.gov (United States)

    Sasikaran, S; Sritharan, K; Balakumar, S; Arasaratnam, V

    2012-09-01

    People rely on the quality of the bottled drinking water, expecting it to be free of microbial contamination and health hazards. To evaluate the quality of bottled drinking water sold in Jaffna peninsula by analysing the physical, chemical and microbial contents and comparing with the recommended Sri Lankan Standard (SLS) values. All bottled water samples sold in Jaffna peninsula were collected. Electrical conductivity, total dissolved solid, pH, calcium, nitrate, total aerobic and anaerobic count, coliform bacterial count and faecal contamination were checked. These are 22 brands of bottled drinking water sold in Jaffna peninsula. The sample had very low electrical conductivity when compared with SLS (750 μS/ cm) and varied from 19 to 253 μS/cm with the mean of 80.53 (±60.92) μS/cm. The pH values of the bottled drinking water brands varied from 4.11 to 7.58 with a mean of 6.2 (±0.75). The total dissolved solid content of the bottled drinking water brands varied from 9 to 123.67 mg/l with a mean of 39.5 (±30.23) mg/l. The calcium content of the bottled drinking water brands varied from 6.48 to 83.77 mg/l with a mean of 49.9 (±25.09) mg/l. The nitrate content of the bottled drinking water brands varied from 0.21 to 4.19 mg/l with the mean of 1.26 (±1.08) mg/l. Aerobic bacterial count varied from 0 to 800 colony forming unit per ml (cfu/ml) with a mean of 262.6 (±327.50) cfu/ml. Among the 22 drinking bottled water brands 14 and 9% of bottled drinking water brands showed fungal and coliform bacterial contaminants respectively. The water brands which contained faecal contamination had either Escherichia coli or Klebsiella spp. The bottled drinking water available for sale do not meet the standards stipulated by SLS.

  6. Measurement standards and the general problem of reference points in chemical analysis

    International Nuclear Information System (INIS)

    Richter, W.; Dube, G.

    2002-01-01

    Besides the measurement standards available in general metrology in the form of the realisations of the units of measurement, measurement standards of chemical composition are needed for the vast field of chemical measurement (measurements of the chemical composition), because it is the main aim of such measurements to quantify non-isolated substances, often in complicated matrices, to which the 'classical' measurement standards and their lower- level derivatives are not directly applicable. At present, material artefacts as well as standard measurement devices serve as chemical measurement standards. These are measurement standards in the full metrological sense only, however, if they are firmly linked to the SI unit in which the composition represented by the standard is expressed. This requirement has the consequence that only a very restricted number of really reliable chemical measurement standards exist at present. Since it is very difficult and time consuming to increase this number substantially and, on the other hand, reliable reference points are increasingly needed for all kinds of chemical measurements, primary methods of measurement and high-level reference measurements will play an increasingly important role for the establishment of worldwide comparability and hence mutual acceptance of chemical measurement results. (author)

  7. Inorganic chemical analysis of environmental materials—A lecture series

    Science.gov (United States)

    Crock, J.G.; Lamothe, P.J.

    2011-01-01

    At the request of the faculty of the Colorado School of Mines, Golden, Colorado, the authors prepared and presented a lecture series to the students of a graduate level advanced instrumental analysis class. The slides and text presented in this report are a compilation and condensation of this series of lectures. The purpose of this report is to present the slides and notes and to emphasize the thought processes that should be used by a scientist submitting samples for analyses in order to procure analytical data to answer a research question. First and foremost, the analytical data generated can be no better than the samples submitted. The questions to be answered must first be well defined and the appropriate samples collected from the population that will answer the question. The proper methods of analysis, including proper sample preparation and digestion techniques, must then be applied. Care must be taken to achieve the required limits of detection of the critical analytes to yield detectable analyte concentration (above "action" levels) for the majority of the study's samples and to address what portion of those analytes answer the research question-total or partial concentrations. To guarantee a robust analytical result that answers the research question(s), a well-defined quality assurance and quality control (QA/QC) plan must be employed. This QA/QC plan must include the collection and analysis of field and laboratory blanks, sample duplicates, and matrix-matched standard reference materials (SRMs). The proper SRMs may include in-house materials and/or a selection of widely available commercial materials. A discussion of the preparation and applicability of in-house reference materials is also presented. Only when all these analytical issues are sufficiently addressed can the research questions be answered with known certainty.

  8. Energy saving analysis and management modeling based on index decomposition analysis integrated energy saving potential method: Application to complex chemical processes

    International Nuclear Information System (INIS)

    Geng, Zhiqiang; Gao, Huachao; Wang, Yanqing; Han, Yongming; Zhu, Qunxiong

    2017-01-01

    Highlights: • The integrated framework that combines IDA with energy-saving potential method is proposed. • Energy saving analysis and management framework of complex chemical processes is obtained. • This proposed method is efficient in energy optimization and carbon emissions of complex chemical processes. - Abstract: Energy saving and management of complex chemical processes play a crucial role in the sustainable development procedure. In order to analyze the effect of the technology, management level, and production structure having on energy efficiency and energy saving potential, this paper proposed a novel integrated framework that combines index decomposition analysis (IDA) with energy saving potential method. The IDA method can obtain the level of energy activity, energy hierarchy and energy intensity effectively based on data-drive to reflect the impact of energy usage. The energy saving potential method can verify the correctness of the improvement direction proposed by the IDA method. Meanwhile, energy efficiency improvement, energy consumption reduction and energy savings can be visually discovered by the proposed framework. The demonstration analysis of ethylene production has verified the practicality of the proposed method. Moreover, we can obtain the corresponding improvement for the ethylene production based on the demonstration analysis. The energy efficiency index and the energy saving potential of these worst months can be increased by 6.7% and 7.4%, respectively. And the carbon emissions can be reduced by 7.4–8.2%.

  9. Sample handling and chemical procedures for efficacious trace analysis of urine by neutron activation analysis

    International Nuclear Information System (INIS)

    Blotcky, A.J.; Rack, E.P.; Roman, F.R.

    1988-01-01

    Important for the determination of trace elements, ions, or compounds in urine by chemical neutron activation analysis is the optimization of sample handling, preirradiation chemistry, and radioassay procedures necessary for viable analysis. Each element, because of its natural abundance in the earth's crust and, hence, its potential for reagent and environmental contamination, requires specific procedures for storage, handling, and preirradiation chemistry. Radioassay techniques for radionuclides vary depending on their half-lives and decay characteristics. Described in this paper are optimized procedures for aluminum and selenium. While 28 Al (T 1/2 = 2.24 min) and 77m Se(T 1/2 = 17.4s) have short half-lives, their gamma-ray spectra are quite different. Aluminum-28 decays by a 1779-keV gamma and 77m Se by a 162-keV gamma. Unlike selenium, aluminum is a ubiquitous element in the environment requiring special handling to minimize contamination in all phases of its analytical determination

  10. Analysis of chemical signatures of alkaliphiles using fatty acid methyl ester analysis

    Directory of Open Access Journals (Sweden)

    Basha Sreenivasulu

    2017-01-01

    Full Text Available Background: Fatty acids occur in nearly all living organisms as the important predominant constituents of lipids. While all fatty acids have essentially the same chemical nature, they are an extremely diverse group of compounds. Materials and Methods: To test the hypothesis, fatty acids of alkaliphiles isolates, Bacillus subtilis SVUNM4, Bacillus licheniformis SVUNM8, Bacillus methylotrohicus SVUNM9, and Paenibacillus dendritiformis SVUNM11, were characterized compared using gas chromatography-mass spectrometry (GC-MS analysis. Results: The content of investigated ten fatty acids, 1, 2-benzenedicarboxylic acid butyl 2-methylpropyl ester, phthalic acid, isobutyl 2-pentyl ester, dibutyl phthalate, cyclotrisiloxane, hexamethyl, cyclotetrasiloxane, octamethyl, dodecamethyl, heptasiloxane 1,1,3,3,5,5,7,7,9,9,11,11,13,13-etradecamethyl, 7,15-dihydroxydehydroabietic acid, methyl ester, di (trimethylsilyl ether, hentriacontane, 2-thiopheneacetic acid, undec-2-enyl ester, obviously varied among four species, suggesting each species has its own fatty acid pattern. Conclusions: These findings demonstrated that GC-MS-based fatty acid profiling analysis provides the reliable platform to classify these four species, which is helpful for ensuring their biotechnological interest and novel chemotaxonomic.

  11. Basic chemically recuperated gas turbines--power plant optimization and thermodynamics second law analysis

    International Nuclear Information System (INIS)

    Alves, Lourenco Gobira; Nebra, Silvia Azucena

    2004-01-01

    One of the proposals to increase the performance of the gas turbines is to improve chemical recuperated cycle. In this cycle, the heat in the turbine exhaust gases is used to heat and modify the chemical characteristics of the fuel. One mixture of natural gas and steam receives heat from the exhaust turbine gases; the mixture components react among themselves producing hot synthesis gas. In this work, an analysis and nonlinear optimization of the cycle were made in order to investigate the temperature and pressure influence on the global cycle performance. The chemical composition in the reformer was assumed according to chemical equilibrium equations, which presents good agreement with data from literature. The mixture of hot gases was treated like ideal gases. The maximum net profit was achieved and a thermodynamic second law analysis was made in order to detect the greatest sources of irreversibility

  12. Analysis of writing inks on paper using direct analysis in real time mass spectrometry.

    Science.gov (United States)

    Jones, Roger W; McClelland, John F

    2013-09-10

    Ink analysis is central to questioned document examination. We applied direct analysis in real time mass spectrometry (DART MS) to ballpoint, gel, and fluid writing ink analysis. DART MS acquires the mass spectrum of an ink while it is still on a document without altering the appearance of the document. Spectra were acquired from ink on a variety of papers, and the spectrum of the blank paper could be subtracted out to produce a cleanly isolated ink spectrum in most cases. Only certain heavy or heavily processed papers interfered. The time since an ink is written on paper has a large effect on its spectrum. DART spectra change radically during the first few months after an ink is written as the more volatile components evaporate, but the spectra stabilize after that. A library-search study involving 166 well-aged inks assessed the ability to identify inks from their DART spectra. The aggregate success rate was 92%. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Physico-chemical analysis and calorific values of poultry manure.

    Science.gov (United States)

    Quiroga, G; Castrillón, L; Fernández-Nava, Y; Marañón, E

    2010-05-01

    Spain is one of the major producers of broilers and laying hens in the European Union, with an overall market share of around 12%. The poultry manure that is produced is usually employed as fertilizer on cropland, either directly or after a composting process. In some cases, however, this waste is transported over 120km to be used as fertilizer, with the resulting high transport costs. In other countries, poultry manure is used as an alternative natural fuel source for power generation. In this study, poultry manure from all the laying hen farms in Asturias was characterized with a view to its possible use as an energy source. The Higher Heating Values on a dry basis (experimental) varies between 12,052 and 13,882kJ/kg. Lower Heating Values (LHVs) on a wet basis range are much lower (mean values of 2664kJ/kg) due to the high moisture content of poultry manure. Accordingly, the co-combustion of this waste with other types of waste such as forest and wood waste (LHV on a wet basis of 8044 and 15,830kJ/kg, respectively) or municipal solid waste (LHV on a wet basis of 10,725kJ/kg) should be considered as an alternative energy source. Chlorine and sulphur contents in dry matter vary around mean values of 0.64% and 0.11%, respectively. The waste also presents high amounts of Ca (4.84%) and K (2.38%). Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  14. The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards.

    Science.gov (United States)

    Anna, Sobek; Sofia, Bejgarn; Christina, Rudén; Magnus, Breitholtz

    2016-08-10

    A major challenge for society is to manage the risks posed by the many chemicals continuously emitted to the environment. All chemicals in production and use cannot be monitored and science-based strategies for prioritization are essential. In this study we review available data to investigate which substances are included in environmental monitoring programs and published research studies reporting analyses of chemicals in Baltic Sea fish between 2000 and 2012. Our aim is to contribute to the discussion of priority settings in environmental chemical monitoring and research, which is closely linked to chemical management. In total, 105 different substances or substance groups were analyzed in Baltic Sea fish. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were the most studied substances or substance groups. The majority, 87%, of all analyses comprised 20% of the substances or substance groups, whereas 46 substance groups (44%) were analyzed only once. Almost three quarters of all analyses regarded a POP-substance (persistent organic pollutant). These results demonstrate that the majority of analyses on environmental contaminants in Baltic Sea fish concern a small number of already regulated chemicals. Legacy pollutants such as POPs pose a high risk to the Baltic Sea due to their hazardous properties. Yet, there may be a risk that prioritizations for chemical analyses are biased based on the knowns of the past. Such biases may lead to society failing in identifying risks posed by yet unknown hazardous chemicals. Alternative and complementary ways to identify priority chemicals are needed. More transparent communication between risk assessments performed as part of the risk assessment process within REACH and monitoring programs, and information on chemicals contained in consumer articles, would offer ways to identify chemicals for environmental analysis.

  15. Angelica sinensis in China-A review of botanical profile, ethnopharmacology, phytochemistry and chemical analysis.

    Science.gov (United States)

    Wei, Wen-Long; Zeng, Rui; Gu, Cai-Mei; Qu, Yan; Huang, Lin-Fang

    2016-08-22

    Angelica sinensis (Oliv.) Diels, known as Dang Gui (in Chinese), is a traditional medicinal and edible plant that has long been used for tonifying, replenishing, and invigorating blood as well as relieving pain, lubricating the intestines, and treating female irregular menstruation and amenorrhea. A. sinensis has also been used as a health product and become increasingly popular in China, Japan, and Korea. This paper aims to provide a systemic review of traditional uses of A. sinensis and its recent advances in the fields of phytochemistry, analytical methods and toxicology. In addition, possible trends, therapeutic potentials, and perspectives for future research of this plant are also briefly discussed. An extensive review of the literature was conducted, and electronic databases including China National Knowledge Infrastructure, PubMed, Google Scholar, Science Direct, and Reaxys were used to assemble the data. Ethnopharmacological literature and digitalised sources of academic libraries were also systematically searched. In addition, information was obtained from local books and The Plant List (TPL, www.theplantlist.org). This study reviews the progress in chemical analysis of A. sinensis and its preparations. Previously and newly established methods, including spectroscopy, thin-layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography(UPLC), and nuclear magnetic resonance analysis (NMR), are summarized. Moreover, identified bioactive components such as polysaccharides, ligustilide and ferulic acid were reviewed, along with analytical methods for quantitative and qualitative determination of target analytes, and fingerprinting authentication, quality evaluation of A. sinensis, and toxicology and pharmacodynamic studies. Scientific reports on crude extracts and pure compounds and formulations revealed a wide range of pharmacological activities, including anti-inflammatory activity

  16. Analysis of abused drugs by selected ion monitoring: quantitative comparison of electron impact and chemical ionization

    International Nuclear Information System (INIS)

    Foltz, R.L.; Knowlton, D.A.; Lin, D.C.K.; Fentiman, A.F. Jr.

    1975-01-01

    A comparison was made of the relative sensitivities of electron impact and chemical ionization when used for selected ion monitoring analysis of commonly abused drugs. For most of the drugs examined chemical ionization using ammonia as the reactant gas gave the largest single m/e ion current response per unit weight of sample. However, if maximum sensitivity is desired it is important to evaluate electron impact and chemical ionization with respect to both maximum response and degree of interference from background and endogenous materials

  17. Validation and assessment of uncertainty of chemical tests as a tool for the reliability analysis of wastewater IPEN

    International Nuclear Information System (INIS)

    Silva, Renan A.; Martins, Elaine A.J.; Furusawa, Helio A.

    2011-01-01

    The validation of analytical methods has become an indispensable tool for the analysis in chemical laboratories, including being required for such accreditation. However, even if a laboratory using validated methods of analysis there is the possibility that these methods generate results discrepant with reality by making necessary the addition of a quantitative attribute (a value) which indicates the degree of certainty the extent or the analytical method used. This measure assigned to the result of measurement is called measurement uncertainty. We estimate this uncertainty with a level of confidence both direction, an analytical result has limited significance if not carried out proper assessment of its uncertainty. One of the activities of this work was to elaborate a program to help the validation and evaluation of uncertainty in chemical analysis. The program was developed with Visual Basic programming language and method of evaluation of uncertainty introduced the following concepts based on the GUM (Guide to the Expression of Uncertainty in Measurement). This evaluation program uncertainty measurement will be applied to chemical analysis in support of the characterization of the Nuclear Fuel Cycle developed by IPEN and the study of organic substances in wastewater associated with professional activities of the Institute. In the first case, primarily for the determination of total uranium and the second case for substances that were generated by human activities and that are contained in resolution 357/2005. As strategy for development of this work was considered the PDCA cycle to improve the efficiency of each step and minimize errors while performing the experimental part. The program should be validated to meet requirements of standards such as, for example, the standard ISO/IEC 17025. The application, it is projected to use in other analytical procedures of both the Nuclear Fuel Cycle and in the control program and chemical waste management of IPEN

  18. Validation and assessment of uncertainty of chemical tests as a tool for the reliability analysis of wastewater IPEN

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Renan A.; Martins, Elaine A.J.; Furusawa, Helio A., E-mail: elaine@ipen.br, E-mail: helioaf@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The validation of analytical methods has become an indispensable tool for the analysis in chemical laboratories, including being required for such accreditation. However, even if a laboratory using validated methods of analysis there is the possibility that these methods generate results discrepant with reality by making necessary the addition of a quantitative attribute (a value) which indicates the degree of certainty the extent or the analytical method used. This measure assigned to the result of measurement is called measurement uncertainty. We estimate this uncertainty with a level of confidence both direction, an analytical result has limited significance if not carried out proper assessment of its uncertainty. One of the activities of this work was to elaborate a program to help the validation and evaluation of uncertainty in chemical analysis. The program was developed with Visual Basic programming language and method of evaluation of uncertainty introduced the following concepts based on the GUM (Guide to the Expression of Uncertainty in Measurement). This evaluation program uncertainty measurement will be applied to chemical analysis in support of the characterization of the Nuclear Fuel Cycle developed by IPEN and the study of organic substances in wastewater associated with professional activities of the Institute. In the first case, primarily for the determination of total uranium and the second case for substances that were generated by human activities and that are contained in resolution 357/2005. As strategy for development of this work was considered the PDCA cycle to improve the efficiency of each step and minimize errors while performing the experimental part. The program should be validated to meet requirements of standards such as, for example, the standard ISO/IEC 17025. The application, it is projected to use in other analytical procedures of both the Nuclear Fuel Cycle and in the control program and chemical waste management of IPEN

  19. The challenge of predicting problematic chemicals using a decision analysis tool: Triclosan as a case study.

    Science.gov (United States)

    Perez, Angela L; Gauthier, Alison M; Ferracini, Tyler; Cowan, Dallas M; Kingsbury, Tony; Panko, Julie

    2017-01-01

    Manufacturers lack a reliable means for determining whether a chemical will be targeted for deselection from their supply chain. In this analysis, 3 methods for determining whether a specific chemical (triclosan) would meet the criteria necessary for being targeted for deselection are presented. The methods included a list-based approach, use of a commercially available chemical assessment software tool run in 2 modes, and a public interest evaluation. Our results indicated that triclosan was included on only 6 of the lists reviewed, none of which were particularly influential in chemical selection decisions. The results from the chemical assessment tool evaluations indicated that human and ecological toxicity for triclosan is low and received scores indicating that the chemical would be considered of low concern. However, triclosan's peak public interest tracked several years in advance of increased regulatory scrutiny of this chemical suggesting that public pressure may have been influential in deselection decisions. Key data gaps and toxicity endpoints not yet regulated such as endocrine disruption potential or phototoxicity, but that are important to estimate the trajectory for deselection of a chemical, are discussed. Integr Environ Assess Manag 2017;13:198-207. © 2016 SETAC. © 2016 SETAC.

  20. Techniques for SMM/THz Chemical Analysis: Investigations and Exploitation of the Large Molecule Limit

    Science.gov (United States)

    2014-03-03

    SECURITY CLASSIFICATION OF: It has long been recognized that the SMM /THz has a unique combinations of attributes that make it attractive as a basis for...applicability of SMM chemical sensors; the second is to explore infrared – SMM double resonance as a basis for atmospheric remote sensing; and the third...2014 12-Aug-2009 11-Aug-2013 Approved for Public Release; Distribution Unlimited Techniques for SMM /THz Chemical Analysis: Investigations and

  1. Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer.

    Science.gov (United States)

    Huang, Guangming; Gao, Liang; Duncan, Jason; Harper, Jason D; Sanders, Nathaniel L; Ouyang, Zheng; Cooks, R Graham

    2010-01-01

    The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  2. Direct chemical synthesis of 1 alpha,25-dihydroxy[26,27-3H] vitamin D3 with high specific activity: its use in receptor studies

    International Nuclear Information System (INIS)

    Napoli, J.L.; Mellon, W.S.; Fivizzani, M.A.; Schnoes, H.K.; DeLuca, H.F.

    1980-01-01

    The first direct chemical synthesis of radiolabeled 1 alpha, 25-dihydroxyvitamin D3 is reported. Unlike all previous syntheses, the new approach does not rely on enzymatic 1 alpha-hydroxylation of radiolabeled precursors. Rather, isotope is introduced in the last synthetic step by reaction of [3H] -methylmagnesium bromide with methyl 1 alpha-hydroxy-26,27-dinorvitamin D3-25-carboxylate to give 1 alpha,25-dihydroxy-[26,27-3H] vitamin D3 with a specific activity of 160 Ci/mmol. Mass spectroscopy confirmed that the radiohormone consists of a single isomer with six tritium atoms bound to carbons 26 and 27. Synthetically produced 1 alpha,25-dihydroxy [26,27-3H] vitamin D3 is indistinguishable from 1 alpha,25-dihydroxy-[26,27-3H] vitamin D3 obtained from the enzymatic 1 alpha-hydroxylation of 25-hydroxy[26,27-3H] vitamin D3 (160 Ci/mmol) by high-pressure liquid chromatography analysis and in the competitive binding assay using chick intestinal cytosol as the receptor source. Equilibrium dissociation constant measurements with the high specific activity radiohormone indicate a Kd of 8.2 x 10(-11) M for the chick intestinal cytosol 1 alpha,25-dihydroxyvitamin D3 receptor--a value considerably lower than the constants in the range of (1-5) x 10(-9) M previously reported

  3. Investigation of chemical modifiers for the direct determination of arsenic in fish oil using high-resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Pereira, Éderson R; de Almeida, Tarcísio S; Borges, Daniel L G; Carasek, Eduardo; Welz, Bernhard; Feldmann, Jörg; Campo Menoyo, Javier Del

    2016-04-01

    High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) has been applied for the development of a method for the determination of total As in fish oil samples using direct analysis. The method does not use any sample pretreatment, besides dilution with 1-propanole, in order to decrease the oil viscosity. The stability and sensitivity of As were evaluated using ruthenium and iridium as permanent chemical modifiers and palladium added in solution over the sample. The best results were obtained with ruthenium as the permanent modifier and palladium in solution added to samples and standard solutions. Under these conditions, aqueous standard solutions could be used for calibration for the fish oil samples diluted with 1-propanole. The pyrolysis and atomization temperatures were 1400 °C and 2300 °C, respectively, and the limit of detection and characteristic mass were 30 pg and 43 pg, respectively. Accuracy and precision of the method have been evaluated using microwave-assisted acid digestion of the samples with subsequent determination by HR-CS GF AAS and ICP-MS; the results were in agreement (95% confidence level) with those of the proposed method. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Electronic tongue - an array of non-specific chemical sensors - for analysis of radioactive solutions

    International Nuclear Information System (INIS)

    Legin, A.; Rudnitskaya, A.; Babain, V.

    2006-01-01

    Multisensor systems, combining chemical sensor arrays with multivariate data processing engines (electronic tongue) rapidly and successfully developing in the last years are capable of simultaneous quantitative analysis of several species, e.g. metals, in complex real solutions. The expansion of the metals (metal ions) and species to be detected in radioactive waste requires permanent enhancement of sensing materials and sensors, with seriously different properties from those known earlier. A prospective direction of R and D of novel sensing materials is exploitation of radiochemical extraction systems and application of extraction substances as active components of new sensors. The sensors based on bidentate phosphorous organic compounds and their combinations with chlorinated cobalt dicarbollide displayed high sensitivity and selectivity to rare-earth metal ions La 3+ , Pr 3+ , Nd 3+ , Eu 3+ . The results indicated good promise for the development of novel analytical tools for detection of multivalent metal cations in different media, particularly in corrosive solutions such as radioactive wastes and solutions derived from spent nuclear fuel. The sensors and sensor arrays made on their basis can play an important role in the development of 'electronic tongue' systems for rapid analytical determinations of different components in complex radioactive solutions

  5. Thermodynamic Analysis of Chemically Reacting Mixtures-Comparison of First and Second Order Models.

    Science.gov (United States)

    Pekař, Miloslav

    2018-01-01

    Recently, a method based on non-equilibrium continuum thermodynamics which derives thermodynamically consistent reaction rate models together with thermodynamic constraints on their parameters was analyzed using a triangular reaction scheme. The scheme was kinetically of the first order. Here, the analysis is further developed for several first and second order schemes to gain a deeper insight into the thermodynamic consistency of rate equations and relationships between chemical thermodynamic and kinetics. It is shown that the thermodynamic constraints on the so-called proper rate coefficient are usually simple sign restrictions consistent with the supposed reaction directions. Constraints on the so-called coupling rate coefficients are more complex and weaker. This means more freedom in kinetic coupling between reaction steps in a scheme, i.e., in the kinetic effects of other reactions on the rate of some reaction in a reacting system. When compared with traditional mass-action rate equations, the method allows a reduction in the number of traditional rate constants to be evaluated from data, i.e., a reduction in the dimensionality of the parameter estimation problem. This is due to identifying relationships between mass-action rate constants (relationships which also include thermodynamic equilibrium constants) which have so far been unknown.

  6. Remote control air sampling and fast chemical analysis of the composition

    Energy Technology Data Exchange (ETDEWEB)

    Kukuczka, A; Golisz, T

    1981-01-01

    In 1979 the Central mine rescue station in Bytom (Poland) developed and introduced into use a new method of remote control air and gas (from fires) sampling and swift chemical analysis of the samples' composition. The device in this method includes: a probe (situated beyond the fire detector directly in the control zone), thick-walled elastic hose, direr, piston pump, rotameter, chromatograph and minicomputer. The basic technical data included in the set: the capacity of the pump 8 1/min, 2.5 kg mass. run on 12 V current (built at the Main Mining Affairs Inst. in Poland); the chromatograph is VARIAN 1420-10 (USA produced),the working gas is helium (balloon volume 40 1), feed--alternating 220V, capacity--1.5 kW, time for measuring gas from fires-- 15 to 20 min (as apposed to the 1.5h spent before when the SRC device was being used) at an accuracy of /sup + -/ 0.05% (volume); the chromatograph works with a mini-computer (model CDS-111C) with a 20 kg mass.and a size of 16 x 46 x 56 cm. As tests in Moszczenica coal mines, where a fire in 504/2 occurred, showed (the chromatograph was located 750m from the probe for burning gases), the method proved to be a good one although the VARIAN 1420-10 was insufficiently reliable and the VARIAN-1400-AEROGRAF proved to be better.

  7. Statistic analysis of grouping in evaluation of the behavior of stable chemical elements and physical-chemical parameters in effluent from uranium mining

    International Nuclear Information System (INIS)

    Pereira, Wagner de S.

    2013-01-01

    The Ore Treatment Unit (UTM) is a uranium mine off. The statistical analysis of clustering was used to evaluate the behavior of stable chemical elements and physico-chemical variables in their effluents. The use of cluster analysis proved effective in the evaluation, allowing to identify groups of chemical elements in physico-chemical variables and group analyzes (element and variables ). As a result, we can say, based on the analysis of the data, a strong link between Ca and Mg and between Al and TR 2 O 3 (rare earth oxides) in the UTM effluents. The SO 4 was also identified as strongly linked to total solids and dissolved and these linked to electrical conductivity. Other associations existed, but were not as strongly linked. Additional collections for seasonal evaluation are required so that assessments can be confirmed. Additional statistics analysis (ordination techniques) should be used to help identify the origins of the groups identified in this analysis. (author)

  8. Comparing direct and iterative equation solvers in a large structural analysis software system

    Science.gov (United States)

    Poole, E. L.

    1991-01-01

    Two direct Choleski equation solvers and two iterative preconditioned conjugate gradient (PCG) equation solvers used in a large structural analysis software system are described. The two direct solvers are implementations of the Choleski method for variable-band matrix storage and sparse matrix storage. The two iterative PCG solvers include the Jacobi conjugate gradient method and an incomplete Choleski conjugate gradient method. The performance of the direct and iterative solvers is compared by solving several representative structural analysis problems. Some key factors affecting the performance of the iterative solvers relative to the direct solvers are identified.

  9. Environmental Chemical Analysis (by B. B. Kebbekus and S. Mitra)

    Science.gov (United States)

    Bower, Reviewed By Nathan W.

    1999-11-01

    This text helps to fill a void in the market, as there are relatively few undergraduate instrumental analysis texts designed specifically for the expanding population of environmental science students. R. N. Reeve's introductory, open-learning Environmental Analysis (Wiley, 1994) is one of the few, and it is aimed at a lower level and is less appropriate for traditional classroom study. Kebbekus and Mitra's book appears to be an update of I. Marr and M. Cresser's excellent 1983 text by the same name (and also published under the Chapman and Hall imprint). It assumes no background in instrumental methods of analysis but it does depend upon a good general chemistry background in kinetic and equilibrium calculations and the standard laboratory techniques found in a classical introduction to analytical chemistry. The slant taken by the authors is aimed more toward engineers, not only in the choice of topics, but also in how they are presented. For example, the statistical significance tests presented follow an engineering format rather than the standard used in analytical chemistry. This approach does not detract from the book's clarity. The writing style is concise and the book is generally well written. The earlier text, which has become somewhat of a classic, took the unusual step of teaching the instruments in the context of their environmental application. It was divided into sections on the "atmosphere", the "hydrosphere", the "lithosphere", and the "biosphere". This text takes a similar approach in the second half, with chapters on methods for air, water, and solid samples. Users who intend to use the book as a text instead of a reference will appreciate the addition of chapters in the first half of the book on spectroscopic, chromatographic, and mass spectrometric methods. The six chapters in these two parts of the book along with four chapters scattered throughout on environmental measurements, sampling, sample preparation, and quality assurance make a nice

  10. Chemical analysis of bioactive substances in seven siberian Saussurea species

    Science.gov (United States)

    Avdeeva, Elena; Reshetov, Yaroslav; Shurupova, Margarita; Zibareva, Larisa; Borisova, Evgeniia; Belousov, Mikhail

    2017-11-01

    Main groups of biologically active substances of seven siberian Saussurea species (S. controversa DC., S. latifolia Ledeb., S. parviflora (Poir.) DC., S. frolowii Ledeb, S. amara (L.) DC., S. salicifolia (L.) DC. and S. daurica Adams) have been studied using paper, thin-layer, performance liquid chromatography, IR spectroscopy, spectrophotometry and mass spectrometry with inductively coupled plasma. Siberian Saussurea species have a rich elemental composition and contain a variety of phenolic compounds, amino acids, polysaccharides. The majority of polysaccharides are accumulated by S. controversa, S. salicifolia and S. frolowii. These plants contain a significant amount of calcium that may be a species characteristic. All plants contain quercetin and its glycosides, in some species luteolin, kaempferol, glycosides of apigenin and myricetin were revealed. Phenolic acids with predominant content of caffeic, chlorogenic and cinnamic acids were found in all the species. The maximum amount of phenolic acids and flavonoids was determined in the grass of S. latifolia, S. controversa and S. daurica. Characteristic absorption bands of lactone carbonyl of sesquiterpenoids in IR spectrum found in S. latifolia, S. controversa, S. daurica, S. amara and S. salicifolia. HPLC / UV analysis showed that peaks with absorption maxima of 242-246 nm due to the presence of α,β-unsaturated ketone group in the structure of ecdysteroids were found in S. salicifolia, S. controversa, S. daurica and S. latifolia.

  11. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    International Nuclear Information System (INIS)

    Cooper, J.F.; Ballazs G.B.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput

  12. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput.

  13. Hydrogen fluoride (HF) substance flow analysis for safe and sustainable chemical industry.

    Science.gov (United States)

    Kim, Junbeum; Hwang, Yongwoo; Yoo, Mijin; Chen, Sha; Lee, Ik-Mo

    2017-11-01

    In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.

  14. Development of a Mechanical Analysis System Considering Chemical Transitions of Barrier Materials

    International Nuclear Information System (INIS)

    Sahara, F.; Murakami, T.; Ito, H.; Kobayashi, I.; Yokozeki, K.

    2006-01-01

    An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of Bentonite-based and Cement-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field that is one of the important environmental conditions in the safety assessment of the TRU waste disposal in Japan. The MACBECE is a system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently their hydraulic conductivity taking both their chemical property changes and deformation into consideration. This paper provides a general description of MACBECE and the results of experimental analysis carried out using MACBECE. (authors)

  15. Endocrine-disrupting Chemicals: Review of Toxicological Mechanisms Using Molecular Pathway Analysis

    Science.gov (United States)

    Yang, Oneyeol; Kim, Hye Lim; Weon, Jong-Il; Seo, Young Rok

    2015-01-01

    Endocrine disruptors are known to cause harmful effects to human through various exposure routes. These chemicals mainly appear to interfere with the endocrine or hormone systems. As importantly, numerous studies have demonstrated that the accumulation of endocrine disruptors can induce fatal disorders including obesity and cancer. Using diverse biological tools, the potential molecular mechanisms related with these diseases by exposure of endocrine disruptors. Recently, pathway analysis, a bioinformatics tool, is being widely used to predict the potential mechanism or biological network of certain chemicals. In this review, we initially summarize the major molecular mechanisms involved in the induction of the above mentioned diseases by endocrine disruptors. Additionally, we provide the potential markers and signaling mechanisms discovered via pathway analysis under exposure to representative endocrine disruptors, bisphenol, diethylhexylphthalate, and nonylphenol. The review emphasizes the importance of pathway analysis using bioinformatics to finding the specific mechanisms of toxic chemicals, including endocrine disruptors. PMID:25853100

  16. Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

    Science.gov (United States)

    Song, Xueping; Jiang, Yan; Rong, Xianjian; Wei, Wei; Wang, Shuangfei; Nie, Shuangxi

    2016-09-01

    The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure. Copyright © 2016. Published by Elsevier Ltd.

  17. Size distribution measurements and chemical analysis of aerosol components

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.

    1995-12-31

    The principal aims of this work were to improve the existing methods for size distribution measurements and to draw conclusions about atmospheric and in-stack aerosol chemistry and physics by utilizing size distributions of various aerosol components measured. A sample dissolution with dilute nitric acid in an ultrasonic bath and subsequent graphite furnace atomic absorption spectrometric analysis was found to result in low blank values and good recoveries for several elements in atmospheric fine particle size fractions below 2 {mu}m of equivalent aerodynamic particle diameter (EAD). Furthermore, it turned out that a substantial amount of analyses associated with insoluble material could be recovered since suspensions were formed. The size distribution measurements of in-stack combustion aerosols indicated two modal size distributions for most components measured. The existence of the fine particle mode suggests that a substantial fraction of such elements with two modal size distributions may vaporize and nucleate during the combustion process. In southern Norway, size distributions of atmospheric aerosol components usually exhibited one or two fine particle modes and one or two coarse particle modes. Atmospheric relative humidity values higher than 80% resulted in significant increase of the mass median diameters of the droplet mode. Important local and/or regional sources of As, Br, I, K, Mn, Pb, Sb, Si and Zn were found to exist in southern Norway. The existence of these sources was reflected in the corresponding size distributions determined, and was utilized in the development of a source identification method based on size distribution data. On the Finnish south coast, atmospheric coarse particle nitrate was found to be formed mostly through an atmospheric reaction of nitric acid with existing coarse particle sea salt but reactions and/or adsorption of nitric acid with soil derived particles also occurred. Chloride was depleted when acidic species reacted

  18. Chemical sensors for breath gas analysis: the latest developments at the Breath Analysis Summit 2013.

    Science.gov (United States)

    Tisch, Ulrike; Haick, Hossam

    2014-06-01

    Profiling the body chemistry by means of volatile organic compounds (VOCs) in the breath opens exciting new avenues in medical diagnostics. Gas sensors could provide ideal platforms for realizing portable, hand-held breath testing devices in the near future. This review summarizes the latest developments and applications in the field of chemical sensors for diagnostic breath testing that were presented at the Breath Analysis Summit 2013 in Wallerfangen, Germany. Considerable progress has been made towards clinically applicable breath testing devices, especially by utilizing chemo-sensitive nanomaterials. Examples of several specialized breath testing applications are presented that are either based on stand-alone nanomaterial-based sensors being highly sensitive and specific to individual breath compounds over others, or on combinations of several highly specific sensors, or on experimental nanomaterial-based sensors arrays. Other interesting approaches include the adaption of a commercially available MOx-based sensor array to indirect breath testing applications, using a sample pre-concentration method, and the development of compact integrated GC-sensor systems. The recent trend towards device integration has led to the development of fully integrated prototypes of point-of-care devices. We describe and compare the performance of several prototypes that are based on different sensing technologies and evaluate their potential as low-cost and readily available next-generation medical devices.

  19. Direct analysis in real time mass spectrometry for analysis of sexual assault evidence.

    Science.gov (United States)

    Musah, Rabi A; Cody, Robert B; Dane, A John; Vuong, Angela L; Shepard, Jason R E

    2012-05-15

    Sexual assault crimes are vastly underreported and suffer from alarmingly low prosecution and conviction rates. The key scientific method to aid in prosecution of such cases is forensic DNA analysis, where biological evidence such as semen collected using a rape test kit is used to determine a suspect's DNA profile. However, the growing awareness by criminals of the importance of DNA in the prosecution of sexual assaults has resulted in increased condom use by assailants as a means to avoid leaving behind their DNA. Thus, other types of trace evidence are important to help corroborate victims' accounts, exonerate the innocent, link suspects to the crime, or confirm penetration. Direct Analysis in Real Time Mass Spectrometry (DART-MS) was employed for the comprehensive characterization of non-DNA trace evidence associated with sexual assault. The ambient ionization method associated with DART-MS is extremely rapid and samples are processed instantaneously, without the need for extraction, sample preparation, or other means that might compromise forensic evidence for future analyses. In a single assay, we demonstrated the ability to identify lubricant formulations associated with sexual assault, such as the spermicide nonoxynol-9, compounds used in condom manufacture, and numerous other trace components as probative evidence. In addition, the method can also serve to identify compounds within trace biological residues, such as fatty acids commonly identified in latent fingerprints. Characterization of lubricant residues as probative evidence serves to establish a connection between the victim and the perpetrator, and the availability of these details may lead to higher rates of prosecution and conviction, as well as more severe penalties. The methodology described here opens the way for the adoption of a comprehensive, rapid, and sensitive analysis for use in crime labs, while providing knowledge that can inform and guide criminal justice policy and practice

  20. Chemical imaging and solid state analysis at compact surfaces using UV imaging

    DEFF Research Database (Denmark)

    Wu, Jian X.; Rehder, Sönke; van den Berg, Frans

    2014-01-01

    and excipients in a non-invasive way, as well as mapping the glibenclamide solid state form. An exploratory data analysis supported the critical evaluation of the mapping results and the selection of model parameters for the chemical mapping. The present study demonstrated that the multi-wavelength UV imaging......Fast non-destructive multi-wavelength UV imaging together with multivariate image analysis was utilized to visualize distribution of chemical components and their solid state form at compact surfaces. Amorphous and crystalline solid forms of the antidiabetic compound glibenclamide...

  1. Chemical Analysis of Plants that Poison Livestock: Successes, Challenges, and Opportunities.

    Science.gov (United States)

    Welch, Kevin D; Lee, Stephen T; Cook, Daniel; Gardner, Dale R; Pfister, James A

    2018-04-04

    Poisonous plants have a devastating impact on the livestock industry as well as human health. To fully understand the effects of poisonous plants, multiple scientific disciplines are required. Chemical analysis of plant secondary compounds is key to identifying the responsible toxins, characterizing their metabolism, and understanding their effects on animals and humans. In this review, we highlight some of the successes in studying poisonous plants and mitigating their toxic effects. We also highlight some of the remaining challenges and opportunities with regards to the chemical analysis of poisonous plants.

  2. Participation in the 1999 IAEA interlaboratory comparison on chemical analysis of groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Joe, Kih Soo; Choi, Kwang Soon; Han, Sun Ho; Suh, Moo Yul; Park, Kyung Kyun; Choi, Ke Chun; Kim, Won Ho

    2000-08-01

    KAERI analytical laboratory participated in the 1999 IAEA interlaboratory comparison on chemical analysis of groundwater organized by IAEA Hydrology Laboratory(RAS/8/084). 13 items such as pH, electroconductivity, HCO{sub 3}, Cl, SO{sub 4}, NO{sub 3}, SiO{sub 2}, B, Li, Na, K, Ca, Mg were analyzed. The result of this program showed that KAERI laboratory was ranked within 10% range from top level. An analytical expert in KAERI attended the 'Consultants' Meeting' at IAEA headquater and prepared the guideline for chemical analysis of groundwater.

  3. Participation in the 1999 IAEA interlaboratory comparison on chemical analysis of groundwater

    International Nuclear Information System (INIS)

    Joe, Kih Soo; Choi, Kwang Soon; Han, Sun Ho; Suh, Moo Yul; Park, Kyung Kyun; Choi, Ke Chun; Kim, Won Ho

    2000-08-01

    KAERI analytical laboratory participated in the 1999 IAEA interlaboratory comparison on chemical analysis of groundwater organized by IAEA Hydrology Laboratory(RAS/8/084). 13 items such as pH, electroconductivity, HCO 3 , Cl, SO 4 , NO 3 , SiO 2 , B, Li, Na, K, Ca, Mg were analyzed. The result of this program showed that KAERI laboratory was ranked within 10% range from top level. An analytical expert in KAERI attended the 'Consultants' Meeting' at IAEA headquater and prepared the guideline for chemical analysis of groundwater

  4. Development of a robotics system for automated chemical analysis of sediments, sludges, and soils

    International Nuclear Information System (INIS)

    McGrail, B.P.; Dodson, M.G.; Skorpik, J.R.; Strachan, D.M.; Barich, J.J.

    1989-01-01

    Adaptation and use of a high-reliability robot to conduct a standard laboratory procedure for soil chemical analysis are reported. Results from a blind comparative test were used to obtain a quantitative measure of the improvement in precision possible with the automated test method. Results from the automated chemical analysis procedure were compared with values obtained from an EPA-certified lab and with results from a more extensive interlaboratory round robin conducted by the EPA. For several elements, up to fivefold improvement in precision was obtained with the automated test method

  5. Biological and chemical removal of Cr(VI) from waste water: cost and benefit analysis.

    Science.gov (United States)

    Demir, Aynur; Arisoy, Münevver

    2007-08-17

    The objective of the present study is cost and benefit analysis of biological and chemical removal of hexavalent chromium [Cr(VI)] ions. Cost and benefit analysis were done with refer to two separate studies on removal of Cr(VI), one of heavy metals with a crucial role concerning increase in environmental pollution and disturbance of ecological balance, through biological adsorption and chemical ion-exchange. Methods of biological and chemical removal were compared with regard to their cost and percentage in chrome removal. According to the result of the comparison, cost per unit in chemical removal was calculated 0.24 euros and the ratio of chrome removal was 99.68%, whereas those of biological removal were 0.14 and 59.3% euros. Therefore, it was seen that cost per unit in chemical removal and chrome removal ratio were higher than those of biological removal method. In the current study where chrome removal is seen as immeasurable benefit in terms of human health and the environment, percentages of chrome removal were taken as measurable benefit and cost per unit of the chemicals as measurable cost.

  6. Mass production of chemicals from biomass-derived oil by directly atmospheric distillation coupled with co-pyrolysis

    Science.gov (United States)

    Zhang, Xue-Song; Yang, Guang-Xi; Jiang, Hong; Liu, Wu-Jun; Ding, Hong-Sheng

    2013-01-01

    Production of renewable commodity chemicals from bio-oil derived from fast pyrolysis of biomass has received considerable interests, but hindered by the presence of innumerable components in bio-oil. In present work, we proposed and experimentally demonstrated an innovative approach combining atmospheric distillation of bio-oil with co-pyrolysis for mass production of renewable chemicals from biomass, in which no waste was produced. It was estimated that 51.86 wt.% of distillate just containing dozens of separable organic components could be recovered using this approach. Ten protogenetic and three epigenetic compounds in distillate were qualitatively identified by gas chromatography/mass spectrometry and quantified by gas chromatography. Among them, the recovery efficiencies of acetic acid, propanoic acid, and furfural were all higher than 80 wt.%. Formation pathways of the distillate components in this process were explored. This work opens up a fascinating prospect for mass production of chemical feedstock from waste biomass. PMID:23350028

  7. Material Cycles and Chemicals: Dynamic Material Flow Analysis of Contaminants in Paper Recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Laner, David; Astrup, Thomas Fruergaard

    2016-01-01

    material source-segregation and collection was the least effective strategy for reducing chemical contamination, if the overall recycling rates should be maintained at the current level (approximately 70% for Europe). The study provides a consistent approach for evaluating contaminant levels in material......This study provides a systematic approach for assessment of contaminants in materials for recycling. Paper recycling is used as an illustrative example. Three selected chemicals, bisphenol A (BPA), diethylhexyl phthalate (DEHP) and mineral oil hydrocarbons (MOHs), are evaluated within the paper...... cycle. The approach combines static material flow analysis (MFA) with dynamic material and substance flow modeling. The results indicate that phasing out of chemicals is the most effective measure for reducing chemical contamination. However, this scenario was also associated with a considerable lag...

  8. Multivariate Analysis of Multiple Datasets: a Practical Guide for Chemical Ecology.

    Science.gov (United States)

    Hervé, Maxime R; Nicolè, Florence; Lê Cao, Kim-Anh

    2018-03-01

    Chemical ecology has strong links with metabolomics, the large-scale study of all metabolites detectable in a biological sample. Consequently, chemical ecologists are often challenged by the statistical analyses of such large datasets. This holds especially true when the purpose is to integrate multiple datasets to obtain a holistic view and a better understanding of a biological system under study. The present article provides a comprehensive resource to analyze such complex datasets using multivariate methods. It starts from the necessary pre-treatment of data including data transformations and distance calculations, to the application of both gold standard and novel multivariate methods for the integration of different omics data. We illustrate the process of analysis along with detailed results interpretations for six issues representative of the different types of biological questions encountered by chemical ecologists. We provide the necessary knowledge and tools with reproducible R codes and chemical-ecological datasets to practice and teach multivariate methods.

  9. Direct analysis of 210Pb in sediment samples: Self-absorption corrections

    International Nuclear Information System (INIS)

    Cutshall, N.H.; Larsen, I.L.; Olsen, C.R.

    1983-01-01

    A procedure for the direct #betta#-ray instrumental analysis of 210 Pb in sediment samples is presented. The problem of dependence of self-absorption on sample composition is solved by making a direct transmission measurement on each sample. The procedure has been verified by intercalibrations and other tests. (orig.)

  10. Prompt gamma-ray spectroscopy and its use for the elemental chemical analysis

    International Nuclear Information System (INIS)

    Deconninck, G.; Demortier, G.; Bodart, F.

    The elemental chemical analysis by nuclear techniques has been widely developed since a quarter of century. In this review the analysis by irradiation of the the sample (solid or liquid) of a majority of chemical elements by means of the charged particles and the detection during this irradiation of the gamma photons characteristic of the element are considered. After a brief account of the physical phenomena peculiar to the prompt detection of photons in comparison with the activation methods where a delayed activity is measured, a brief description of the experimental equipment for this kind of analysis is given. A comprehensive critical survey of the recent applications to the analysis of metals, semiconductors and electric insulating substances is presented. The necessary informations for the choice of the nuclear reaction to use for a specific analysis are contained in a set of tables. (AF)

  11. 3-D simulation of soot formation in a direct-injection diesel engine based on a comprehensive chemical mechanism and method of moments

    Science.gov (United States)

    Zhong, Bei-Jing; Dang, Shuai; Song, Ya-Na; Gong, Jing-Song

    2012-02-01

    Here, we propose both a comprehensive chemical mechanism and a reduced mechanism for a three-dimensional combustion simulation, describing the formation of polycyclic aromatic hydrocarbons (PAHs), in a direct-injection diesel engine. A soot model based on the reduced mechanism and a method of moments is also presented. The turbulent diffusion flame and PAH formation in the diesel engine were modelled using the reduced mechanism based on the detailed mechanism using a fixed wall temperature as a boundary condition. The spatial distribution of PAH concentrations and the characteristic parameters for soot formation in the engine cylinder were obtained by coupling a detailed chemical kinetic model with the three-dimensional computational fluid dynamic (CFD) model. Comparison of the simulated results with limited experimental data shows that the chemical mechanisms and soot model are realistic and correctly describe the basic physics of diesel combustion but require further development to improve their accuracy.

  12. Potential of Palm Olein as Green Lubricant Source: Lubrication Analysis and Chemical Characterisation

    International Nuclear Information System (INIS)

    Darfizzi Derawi; Jumat Salimon

    2014-01-01

    Palm olein (PO o ) is widely used as edible oil in tropical countries. The lubrication properties and chemical compositions of PO o being considered to be used as renewable raw material for bio lubricant synthesis. PO o is suitable to be used directly as bio lubricant for medium temperature industrial applications. Palm olein has good viscosity index, oxidative stability, flash and fire point as a lubricant source. PO o contains unsaturated triacylglycerols (TAG): Palmitin-Olein-Olein, POO (33.3 %), Palmitin-Olein-Palmitin, POP (29.6 %), which are very important to produce good lubricant properties. This unsaturated bond is preferable in chemical modification to produce bio lubricant. The chemical compositions of PO o were tested by using high performance liquid chromatography (HPLC) and gas chromatography (GC) techniques. (author)

  13. Forecasting global developments in the basic chemical industry for environmental policy analysis

    International Nuclear Information System (INIS)

    Broeren, M.L.M.; Saygin, D.; Patel, M.K.

    2014-01-01

    The chemical sector is the largest industrial energy user, but detailed analysis of its energy use developments lags behind other energy-intensive sectors. A cost-driven forecasting model for basic chemicals production is developed, accounting for regional production costs, demand growth and stock turnover. The model determines the global production capacity placement, implementation of energy-efficient Best Practice Technology (BPT) and global carbon dioxide (CO 2 ) emissions for the period 2010–2030. Subsequently, the effects of energy and climate policies on these parameters are quantified. About 60% of new basic chemical production capacity is projected to be placed in non-OECD regions by 2030 due to low energy prices. While global production increases by 80% between 2010 and 2030, the OECD's production capacity share decreases from 40% to 20% and global emissions increase by 50%. Energy pricing and climate policies are found to reduce 2030 CO 2 emissions by 5–15% relative to the baseline developments by increasing BPT implementation. Maximum BPT implementation results in a 25% reduction. Further emission reductions require measures beyond energy-efficient technologies. The model is useful to estimate general trends related to basic chemicals production, but improved data from the chemical sector is required to expand the analysis to additional technologies and chemicals. - Highlights: • We develop a global cost-driven forecasting model for the basic chemical sector. • We study regional production, energy-efficient technology, emissions and policies. • Between 2010 and 2030, 60% of new chemicals capacity is built in non-OECD regions. • Global CO 2 emissions rise by 50%, but climate policies may limit this to 30–40%. • Measures beyond energy efficiency are needed to prevent increasing CO 2 emissions

  14. [Relativity of commercial specification of Menthae Herba based on chemical analysis].

    Science.gov (United States)

    Ye, Dan; Zhao, Ming; Shao, Yang; Ouyang, Zhen; Peng, Hua-sheng; Han Bang-xing; Zhang, Wei-wan-qi; Gu, Xue-mei

    2015-01-01

    In order to compare the differences of 35 Menthae Herba samples collected on the market and at producing areas, the contents of six total terpenoids, the essential oil and chromatographic fingerprints were analyzed, which provided evidences for drawing up the commodity specifications and grading criteria of Menthae Herba. GC-MS method was used to analyze the chemical constituents of 35 different samples. The chromatographic fingerprints obtained by using GC were then evaluated by similarity analysis, hierarchical clustering analysis and principal component analysis. The relativity between the content of six terpenoids and the essential oil were studied. In this study, the chemical profiles of 35 samples from different producing areas had significant disparity. All samples collected in the report could be categorized into four chemical types, L-menthol, pulegone, carvone and L-menthone, but the chemical profiles had no relationship with the areas. The chromatographic fingerprints of the samples from different types were dissimilar, while the different producing areas were difficult to be separated. It was indicated that the content of volatile oil was positively correlated with the content of L-menthol and the sum of six total terpenoids. The content of the essential oil, L-menthol and the sum of six total terpenoids of Menthae Herba were considered as one of the commercial specifications and grading criteria. These results in the research could be helpful to draw up the commercial specification and grading criteria of Menthae Herba from a view of chemical information.

  15. Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources.

    Science.gov (United States)

    Brack, Werner; Dulio, Valeria; Ågerstrand, Marlene; Allan, Ian; Altenburger, Rolf; Brinkmann, Markus; Bunke, Dirk; Burgess, Robert M; Cousins, Ian; Escher, Beate I; Hernández, Félix J; Hewitt, L Mark; Hilscherová, Klára; Hollender, Juliane; Hollert, Henner; Kase, Robert; Klauer, Bernd; Lindim, Claudia; Herráez, David López; Miège, Cécil; Munthe, John; O'Toole, Simon; Posthuma, Leo; Rüdel, Heinz; Schäfer, Ralf B; Sengl, Manfred; Smedes, Foppe; van de Meent, Dik; van den Brink, Paul J; van Gils, Jos; van Wezel, Annemarie P; Vethaak, A Dick; Vermeirssen, Etienne; von der Ohe, Peter C; Vrana, Branislav

    2017-01-15

    Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic "chemical status" assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment. Copyright © 2016. Published by Elsevier B.V.

  16. Energy Effectiveness of Direct UV and UV/H2O2 Treatment of Estrogenic Chemicals in Biologically Treated Sewage

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2012-01-01

    and the UV/H2O2-treatment were investigated in biologically treated sewage for most of the estrogenic compounds reported in wastewater. The investigated compounds included parabens, industrial phenols, sunscreen chemicals and steroid estrogens. Treatment experiments were performed in a flow through set...

  17. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography 64 to 70 Moisture by the Coulomet...

  18. Chemical analysis of bleach and hydroxide-based solutions after decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX).

    Science.gov (United States)

    Hopkins, F B; Gravett, M R; Self, A J; Wang, M; Chua, Hoe-Chee; Hoe-Chee, C; Lee, H S Nancy; Sim, N Lee Hoi; Jones, J T A; Timperley, C M; Riches, J R

    2014-08-01

    Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). We confirm the formation of N,N-diisopropylformamide and N,N-diisopropylamine following decontamination of VX with hypochlorite-based solution, whereas they were not detected in extracts of hydroxide-based decontamination solutions by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography-mass spectrometry. We report the electron ionisation and chemical ionisation mass spectroscopic details, retention indices, and NMR spectra of N,N-diisopropylformamide and N,N-diisopropylamine, as well as analytical methods suitable for their analysis and identification in solvent extracts and decontamination residues.

  19. SWOT analysis for safer carriage of bulk liquid chemicals in tankers.

    Science.gov (United States)

    Arslan, Ozcan; Er, Ismail Deha

    2008-06-15

    The application of strengths, weaknesses, opportunities and threats (SWOT) analysis to formulation of strategy concerned with the safe carriage of bulk liquid chemicals in maritime tankers was examined in this study. A qualitative investigation using SWOT analysis has been implemented successfully for ships that are designed to carry liquid chemicals in bulk. The originality of this study lies in the use of SWOT analysis as a management tool to formulate strategic action plans for ship management companies, ship masters and officers for the carriage of dangerous goods in bulk. With this transportation-based SWOT analysis, efforts were made to explore the ways and means of converting possible threats into opportunities, and changing weaknesses into strengths; and strategic plans of action were developed for safer tanker operation.

  20. Meta-analysis of toxicity and teratogenicity of 133 chemicals from zebrafish developmental toxicity studies

    Science.gov (United States)

    Zebrafish developmental toxicity testing is an emerging field, which faces considerable challenges regarding data meta-analysis and the establishment of standardized test protocols. Here, we present an initial correlation study on toxicity of 133 chemicals based on data in the li...