WorldWideScience

Sample records for chemical state analysis

  1. A study of quantitative chemical state analysis on cerium surface by using auger electron spectroscopy and factor analysis

    International Nuclear Information System (INIS)

    A reaction with oxygen during oxygen exposure to Cerium metal surface under ultra high vacuum condition and depth profiling on formed Cerium oxide layer were investigated in term of chemical state analysis by Auger electron spectroscopy (AES) and by factor analysis. Principal component analysis (PCA) on Ce NON Auger spectra suggested that three physically meaningful components existed from the analyzed data in both cases. After the PCA, three spectra were extracted from the data and these showed significant peak shape changes in each spectrum which were corresponding to different chemical states. In addition, the profiles constructed by factor analysis showed the chemical state changes on the Cerium metal surface during oxidation or chemical depth distributions in the oxide layer. (author)

  2. 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

    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, 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 is...... microcrystalline cellulose together with magnesium stearate as excipients were used as model materials in the compacts. The UV imaging based drug and excipient distribution was in good agreement with hyperspectral NIR imaging. The UV wavelength region can be utilized in distinguishing between glibenclamide and...

  3. Superconducting High-Resolution X-Ray Spectrometers for Chemical State Analysis of Dilute Samples

    International Nuclear Information System (INIS)

    Cryogenic X-ray spectrometers operating at temperatures below 1 K combine high energy resolution with broadband efficiency for X-ray energies up to 10 keV. They offer advantages for chemical state analysis of dilute samples by fluorescence-detected X-ray absorption spectroscopy (XAS) in cases where conventional Ge or Si(Li) detectors lack energy resolution and grating spectrometers lack detection efficiency. We are developing soft X-ray spectrometers based on superconducting Nb-Al-AlOx-Al-Nb tunnel junction (STJ) technology. X-rays absorbed in one of the superconducting electrodes generate excess charge carriers in proportion to their energy, thereby producing a measurable temporary increase in tunneling current. For STJ operation at the synchrotron, we have designed a two-stage adiabatic demagnetization refrigerator (ADR) with a cold finger that holds a 3 x 3 array of STJs inside the UHV sample chamber at a temperature of ∼0.1 K within ∼15 mm of a room temperature sample. Our STJ spectrometer can have an energy resolution below 10 eV FWHM for X-ray energies up to 1 keV, and has total count rate capabilities above 100,000 counts/s. We will describe detector performance in synchrotron-based X-ray fluorescence experiments and demonstrate its use for XAS on a dilute metal site in a metalloprotein

  4. In situ chemical state analysis of buried polymer/metal adhesive interface by hard X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: • Chemical state analysis of the buried rubber/brass interface is conducted by HAXPES. • Ultrathin rubber films are prepared on the brass surface by two methods. • A high density of Cu2S is found on the rubber side of the buried adhesive layer. • The chemical states of the buried and exposed interfaces are compared. - Abstract: Chemical state analysis of adhesive interfaces is important to understand an adhesion mechanism between two different materials. Although photoelectron spectroscopy (PES) is an ideal tool for such an analysis, the adhesive interfaces must be exposed to the surface because PES is essentially a surface sensitive technique. However, an in situ observation is possible by hard X-ray PES (HAXPES) owing to its large probing depth. In the present study, HAXPES is applied to investigate the adhesive interface between rubber and brass without exposing the interface. It is demonstrated that copper sulfides formed at the buried rubber/brass interface are distinguished from S-containing species in the rubber overlayer. The chemical state of the buried interface is compared with that of the “exposed” interface prepared by so-called a filter-paper method

  5. Computational analysis of the mechanism of chemical reactions in terms of reaction phases: hidden intermediates and hidden transition States.

    Science.gov (United States)

    Kraka, Elfi; Cremer, Dieter

    2010-05-18

    Computational approaches to understanding chemical reaction mechanisms generally begin by establishing the relative energies of the starting materials, transition state, and products, that is, the stationary points on the potential energy surface of the reaction complex. Examining the intervening species via the intrinsic reaction coordinate (IRC) offers further insight into the fate of the reactants by delineating, step-by-step, the energetics involved along the reaction path between the stationary states. For a detailed analysis of the mechanism and dynamics of a chemical reaction, the reaction path Hamiltonian (RPH) and the united reaction valley approach (URVA) are an efficient combination. The chemical conversion of the reaction complex is reflected by the changes in the reaction path direction t(s) and reaction path curvature k(s), both expressed as a function of the path length s. This information can be used to partition the reaction path, and by this the reaction mechanism, of a chemical reaction into reaction phases describing chemically relevant changes of the reaction complex: (i) a contact phase characterized by van der Waals interactions, (ii) a preparation phase, in which the reactants prepare for the chemical processes, (iii) one or more transition state phases, in which the chemical processes of bond cleavage and bond formation take place, (iv) a product adjustment phase, and (v) a separation phase. In this Account, we examine mechanistic analysis with URVA in detail, focusing on recent theoretical insights (with a variety of reaction types) from our laboratories. Through the utilization of the concept of localized adiabatic vibrational modes that are associated with the internal coordinates, q(n)(s), of the reaction complex, the chemical character of each reaction phase can be identified via the adiabatic curvature coupling coefficients, A(n,s)(s). These quantities reveal whether a local adiabatic vibrational mode supports (A(n,s) > 0) or resists

  6. Islamic State and Chemical Weapons

    Directory of Open Access Journals (Sweden)

    Lukáš Rafay

    2016-09-01

    Full Text Available The article deals with topic of Islamic State and chemical weapons. The issue is analysed in three dimensions: origin of used chemical weapons and possibility of independent production; known chemical attacks and tactical regularities in their execution; and traits of future chemical terrorist attacks. By providing a thorough examination of the problem, the article aims at predicting the future development of the group’s chemical program as well as describing any prospective chemical terrorist attacks in Europe

  7. 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...

  8. Quantitative chemical state analysis of supported vanadium oxide catalysts by high resolution vanadium Kα spectroscopy.

    Science.gov (United States)

    Yamamoto, Takashi; Nanbu, Fumitaka; Tanaka, Tsunehiro; Kawai, Jun

    2011-03-01

    Oxidation states of vanadium species on Al(2)O(3), SiO(2), and TiO(2) were quantitatively analyzed by least-squares fitting of V Kα spectra recorded with a two-crystal X-ray fluorescence spectrometer. Uncertainties of analytical results by the normalization procedure, and coefficient of validation and the reduction behavior of vanadium species by X-ray irradiation were discussed. The V(5+)/V(4+)/V(3+) ratios on Al(2)O(3), SiO(2), and TiO(2) calcined at 773 K in air were determined to be ca. 6/3/1, 3/6/1, and 5/4/1, respectively. The possible chemical states of vanadium species on supports were proposed. PMID:21302919

  9. Analysis of local structure and chemical state by using in-house XAFS

    International Nuclear Information System (INIS)

    X-ray absorption near-edge structure (XANES) is useful to analysis of the valence of selected element or the symmetry surrounding it. XAFS measurements by using in-house X-ray absorption spectrometer have high potential to apply to analyze the local structure or the electronic states of materials, it is not so popular recently with increasing the use of synchrotron facilities has become prevailing into various fields. The capacity of the in-house XAFS is shown in this paper along with some examples of experiments by a spectrometer with X-ray generator of only 3 kW. (author)

  10. Demystifying "oxi" cocaine: Chemical profiling analysis of a "new Brazilian drug" from Acre State.

    Science.gov (United States)

    da Silva Junior, Ronaldo C; Gomes, Cezar S; Goulart Júnior, Saulo S; Almeida, Fernanda V; Grobério, Tatiane S; Braga, Jez W B; Zacca, Jorge J; Vieira, Maurício L; Botelho, Elvio D; Maldaner, Adriano O

    2012-09-10

    Recent information from various sources suggests that a new illicit drug, called "oxi", is being spread across Brazil. It would be used in the smoked form and it would look like to crack cocaine: usually small yellowish or light brown stones. As fully released in the media, "oxi" would differ from crack cocaine in the sense that crack would contain carbonate or bicarbonate salts whereas "oxi" would include the addition of calcium oxide and kerosene (or gasoline). In this context, this work presents a chemical profiling comparative study between "oxi" street samples seized by the Civil Police of the State of Acre (CP/AC) and samples associated with both international and interstate drug trafficking seized by the Brazilian Federal Police in Acre (FP/AC). The outcome of this work assisted Brazilian authorities to stop inaccurate and alarmist releases on this issue. It may be of good use by the forensic community in order to better understand matters in their efforts to guide local law enforcement agencies in case such claims reach the international illicit market. PMID:22571827

  11. Chemical state analysis of Cu, Cu2O and CuO with WDX using an ion microbeam

    International Nuclear Information System (INIS)

    The possibility of chemical state analysis with a wavelength-dispersive X-ray spectrometer system for particle-induced X-ray emission (WDX-PIXE) using a light ion microbeam is described. High-resolution Cu Lα1,2 and Lβ1 X-ray spectra from Cu, Cu2O and CuO targets are measured using this spectrometer system. The incident microbeam is focused 2.0 MeV protons with a beam size of 100(H)x30(V) μm2. The Cu L X-ray spectra show two clear main peaks and their satellites. The main peaks are the Lα1,2 and the Lβ1 diagram lines, respectively. Due to a high detection efficiency of our spectrometer equipped with a position-sensitive detector for soft X-rays, the intensity ratio Lβ1/Lα1,2 is observable, which is the lowest for pure Cu metal, and the largest for CuO. Moreover, the Lα1,2 X-ray spectrum for CuO shows a large shoulder at the high energy side of the main peak, which is considered to be due to the chemical bonding between Cu and O atoms. The results show that this system can be used for chemical state analysis for various compound materials and for analyzing small areas of materials or small particles

  12. Variability of Ecosystem State in Rivers Containing Natural Dams: A Chemical Analysis

    Science.gov (United States)

    Reynolds, Z. A.

    2015-12-01

    Flooding, and the resulting economic damage to roads and property, is associated with natural dams such as beaver dams or log jams. For this reason, humans often remove natural dams; however, river reaches with natural dams provide very different ecosystem services in comparison with free-flowing river reaches. Therefore, the goal of this project is to assess the differences in ecosystem state between these different river reach types in the northeastern United States. We focused on differences in basic chemistry (e.g., dissolved oxygen, pH, temperature, and organic carbon) to assess the impact of natural dams on river ecosystem state. Study sites include rivers in the White Mountains and southeastern New Hampshire at locations with beaver dams, beaver ponds, beaver meadows, log jams, and free-flowing reaches. Dissolved oxygen, ORP, pH, temperature, and conductivity were measured in the field with a YSI Professional Plus meter. Water samples were collected for subsequent laboratory analysis of total organic carbon with a Shimadzu TOC-L. Preliminary results show that the chemistry of river water varies with feature type. Most significantly, dissolved oxygen concentrations are highest in free-flowing reaches and lowest in beaver ponds. Although beaver ponds are often associated with lower pH, due the increased concentration of organic acids, some beaver ponds can increase pH when compared to free-flowing reaches on the same river. Early results also show that water chemistry returns quickly to the chemistry typical of the free-flowing river reaches after being altered by a natural dam. Overall, natural dams create a river system that has more heterogeneity, and therefore has opportunities to provide more ecosystem functions, than a purely free-flowing river; this can increase the number of supported instream and riparian species. By increasing the understanding of how natural dams affect the chemistry of river water, river engineers can improve their decisions on how

  13. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale

    2007-09-01

    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This

  14. Structure, characteristics and potential of commercial equipment Total Reflection X Ray Fluorescence for multielemental chemical analysis: Current State

    International Nuclear Information System (INIS)

    The method Total Reflection X-Ray Fluorescence for chemical multielemental analysis has evolved in the last years with the availability of commercial systems for applications in the field of electronics and chemical multielemental analysis in samples of mineral and biological origin. The basic components of these equipment cam be summarized in a system of excitement, a geometric arrangement (optics) for collimate and monochromatize the primary radiation, a X-rays detector, and the electronic si stem for spectral data acquisition including the software for spectra unfolding, qualitative and quantitative analysis, and the complete instrument operation. Additionally the makers offer the conventional 45 degrees geometry for the excitement solid and liquid samples of bigger volume in direct form. The available bibliographical and commercial information to the moment of preparing this lecture, basically reports the following types of components for the X-rays spectrometers in geometry of total reflection chemical multielemental analysis (they are excluded those RTFX equipment dedicated to the electronic industry for quality control of Si wafers purity used for the production of circuits (chips). Excitation: X-rays tube of high vacuum with power among 1300 to 2000 watts and different types of anode; X-rays ceramic metal tube, with power up to 40 watts, and anode of molybdenum, tug steno, etc. Detection: detector semiconductor of silicon-lithium cooled with liquid nitrogen; detector of solid state silicon cooled electrically (Si-PI N diode or detector of diffused silicon Sdd). Optics: multi stratum monochromator; multi stratum Ni-C monochromator; double multi stratum monochromator. Electronic: spectroscopical amplifier espectroscopico and ana logical digital convertor adapted to a personal computer IBM compatible, with software for qualitative and quantitative analysis of samples by means of Windows, and for the complete operation of the analyzer from the Pc. In this work

  15. 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...

  16. Quality Parameters and Chemical Analysis for Biodiesel Produced in the United States in 2011

    Energy Technology Data Exchange (ETDEWEB)

    Alleman, T. L.; Fouts, L.; Chupka, G.

    2013-03-01

    Samples of biodiesel (B100) from producers and terminals in 2011were tested for critical properties: free and total glycerin, flash point, cloud point, oxidation stability, cold soak filterability, and metals. Failure rates for cold soak filterability and oxidation stability were below 5%. One sample failed flash point due to excess methanol. One sample failed oxidation stability and metal content. Overall, 95% of the samples from this survey met biodiesel quality specification ASTM D6751. In 2007, a sampling of B100 from production facilities showed that nearly 90% met D6751. In samples meeting D6751, calcium was found above the method detection limit in nearly half the samples. Feedstock analysis revealed half the biodiesel was produced from soy and half was from mixed feedstocks. The saturated fatty acid methyl ester concentration of the B100 was compared to the saturated monoglyceride concentration as a percent of total monoglyceride. The real-world correlation of these properties was very good. The results of liquid chromatograph measurement of monoglycerides were compared to ASTM D6751. Agreement between the two methods was good, particularly for total monoglycerides and unsaturated monoglycerides. Because only very low levels of saturated monoglycerides measured, the two methods had more variability, but the correlation was still acceptable.

  17. 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.

  18. Fast variance reduction for steady-state simulation and sensitivity analysis of stochastic chemical systems using shadow function estimators

    International Nuclear Information System (INIS)

    We address the problem of estimating steady-state quantities associated to systems of stochastic chemical kinetics. In most cases of interest, these systems are analytically intractable, and one has to resort to computational methods to estimate stationary values of cost functions. In this work, we introduce a novel variance reduction algorithm for stochastic chemical kinetics, inspired by related methods in queueing theory, in particular the use of shadow functions. Using two numerical examples, we demonstrate the efficiency of the method for the calculation of steady-state parametric sensitivities and evaluate its performance in comparison to other estimation methods

  19. Fast variance reduction for steady-state simulation and sensitivity analysis of stochastic chemical systems using shadow function estimators

    Science.gov (United States)

    Milias-Argeitis, Andreas; Lygeros, John; Khammash, Mustafa

    2014-07-01

    We address the problem of estimating steady-state quantities associated to systems of stochastic chemical kinetics. In most cases of interest, these systems are analytically intractable, and one has to resort to computational methods to estimate stationary values of cost functions. In this work, we introduce a novel variance reduction algorithm for stochastic chemical kinetics, inspired by related methods in queueing theory, in particular the use of shadow functions. Using two numerical examples, we demonstrate the efficiency of the method for the calculation of steady-state parametric sensitivities and evaluate its performance in comparison to other estimation methods.

  20. Level crossing analysis of chemically induced dynamic nuclear polarization: Towards a common description of liquid-state and solid-state cases

    Science.gov (United States)

    Sosnovsky, Denis V.; Jeschke, Gunnar; Matysik, Jörg; Vieth, Hans-Martin; Ivanov, Konstantin L.

    2016-04-01

    Chemically Induced Dynamic Nuclear Polarization (CIDNP) is an efficient method of creating non-equilibrium polarization of nuclear spins by using chemical reactions, which have radical pairs as intermediates. The CIDNP effect originates from (i) electron spin-selective recombination of radical pairs and (ii) the dependence of the inter-system crossing rate in radical pairs on the state of magnetic nuclei. The CIDNP effect can be investigated by using Nuclear Magnetic Resonance (NMR) methods. The gain from CIDNP is then two-fold: it allows one to obtain considerable amplification of NMR signals; in addition, it provides a very useful tool for investigating elusive radicals and radical pairs. While the mechanisms of the CIDNP effect in liquids are well established and understood, detailed analysis of solid-state CIDNP mechanisms still remains challenging; likewise a common theoretical frame for the description of CIDNP in both solids and liquids is missing. Difficulties in understanding the spin dynamics that lead to the CIDNP effect in the solid-state case are caused by the anisotropy of spin interactions, which increase the complexity of spin evolution. In this work, we propose to analyze CIDNP in terms of level crossing phenomena, namely, to attribute features in the CIDNP magnetic field dependence to Level Crossings (LCs) and Level Anti-Crossings (LACs) in a radical pair. This approach allows one to describe liquid-state CIDNP; the same holds for the solid-state case where anisotropic interactions play a significant role in CIDNP formation. In solids, features arise predominantly from LACs, since in most cases anisotropic couplings result in perturbations, which turn LCs into LACs. We have interpreted the CIDNP mechanisms in terms of the LC/LAC concept. This consideration allows one to find analytical expressions for a wide magnetic field range, where several different mechanisms are operative; furthermore, the LAC description gives a way to determine CIDNP sign

  1. Solid state NMR chemical shift assignment and conformational analysis of a cellulose binding protein facilitated by optimized glycerol enrichment.

    Science.gov (United States)

    Ivanir, Hadar; Goldbourt, Amir

    2014-07-01

    Magic-angle spinning solid-state NMR has been applied to study CBM3b-Cbh9A (CBM3b), a cellulose binding module protein belonging to family 3b. It is a 146-residue protein having a unique nine-stranded β-sandwich fold, in which 35% of the structure is in a β-sheet conformation and the remainder of the protein is composed of loops and unstructured regions. Yet, the protein can be crystalized and it forms elongated needles. Close to complete chemical shift assignment of the protein was obtained by combining two- and three-dimensional experiments using a fully labeled sample and a glycerol-labeled sample. The use of an optimized protocol for glycerol-based sparse labeling reduces sample preparation costs and facilitates the assignment of the large number of aromatic signals in this protein. Conformational analysis shows good correlation between the NMR-predicted secondary structure and the reported X-ray crystal structure, in particular in the structured regions. Residues which show high B-factor values are situated mainly in unstructured regions, and are missing in our spectra indicating conformational flexibility rather than heterogeneity. Interestingly, long-range contacts, which could be clearly detected for tyrosine residues, could not be observed for aromatic phenylalanine residues pointing into the hydrophobic core, suggesting possible high ring mobility. These studies will allow us to further investigate the cellulose-bound form of CBM proteins. PMID:24824437

  2. Radiometric chemical analysis

    International Nuclear Information System (INIS)

    The radiometric method of analysis is noted for its sensitivity and its simplicity in both apparatus and procedure. A few inexpensive radioactive reagents permit the analysis of a wide variety of chemical elements and compounds. Any particular procedure is generally applicable over a very wide range of concentrations. It is potentially an analytical method of great industrial significance. Specific examples of analyses are cited to illustrate the potentialities of ordinary equipment. Apparatus specifically designed for radiometric chemistry may shorten the time required, and increase the precision and accuracy for routine analyses. A sensitive and convenient apparatus for the routine performance of radiometric chemical analysis is a special type of centrifuge which has been used in obtaining the data presented in this paper. The radioactivity of the solution is measured while the centrifuge is spinning. This device has been used as the basis for an automatic analyser for phosphate ion, programmed to follow a sequence of unknown sampling, reagent mixing, centrifugation, counting data presentation, and phosphate replenishment. This analyser can repeatedly measure phosphate-concentration in the range of 5 to 50 ppm with an accuracy of ±5%. (author)

  3. Constraints on the Global-scale Chemical Weathering State of Mars From TES Results Based on Spectral Analysis of Chemically Weathered Basalts

    Science.gov (United States)

    Michalski, J. R.; Kraft, M. D.; Sharp, T. G.; Christensen, P. R.

    2005-12-01

    mineralogy from thermal infrared data; weathering serves to bias igneous interpretations toward rocks of higher silica and alkali contents. Trends observed in the spectral analysis of chemically weathered CRBG rock surfaces could explain some of the spectral trends observed at Mars, suggesting that martian dark region basalts have been chemically weathered under consistently low-water, or only episodically wet surface conditions.

  4. Coulometry in quantitative chemical analysis and physico-chemical research

    International Nuclear Information System (INIS)

    Electroanalytical methods such as potentiometry, amperometry, coulometry and voltammetry are well established and routinely employed in quantitative chemical analysis as well as in chemical research. Coulometry is one of the most important electroanalytical techniques, which involves change in oxidation state of electro active species by heterogeneous electron transfer. In primary coulometric method, uranium is determined at mercury pool electrode and plutonium at platinum gauze electrode

  5. Chemical analysis by nuclear techniques

    International Nuclear Information System (INIS)

    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

  6. Analysis of copper-rich precipitates in silicon: chemical state,gettering, and impact on multicrystalline silicon solar cellmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Buonassisi, Tonio; Marcus, Matthew A.; Istratov, Andrei A.; Heuer, Matthias; Ciszek, Theodore F.; Lai, Barry; Cai, Zhonghou; Weber,Eicke R.

    2004-11-08

    In this study, synchrotron-based x-ray absorption microspectroscopy (mu-XAS) is applied to identifying the chemical states of copper-rich clusters within a variety of silicon materials, including as-grown cast multicrystalline silicon solar cell material with high oxygen concentration and other silicon materials with varying degrees of oxygen concentration and copper contamination pathways. In all samples, copper silicide (Cu3Si) is the only phase of copper identified. It is noted from thermodynamic considerations that unlike certain metal species, copper tends to form a silicide and not an oxidized compound because of the strong silicon-oxygen bonding energy; consequently the likelihood of encountering an oxidized copper particle in silicon is small, in agreement with experimental data. In light of these results, the effectiveness of aluminum gettering for the removal of copper from bulk silicon is quantified via x-ray fluorescence microscopy (mu-XRF),and a segregation coefficient is determined from experimental data to beat least (1-2)'103. Additionally, mu-XAS data directly demonstrates that the segregation mechanism of Cu in Al is the higher solubility of Cu in the liquid phase. In light of these results, possible limitations for the complete removal of Cu from bulk mc-Si are discussed.

  7. Chemical Implementation of Finite-State Machines

    Science.gov (United States)

    Hjelmfelt, Allen; Weinberger, Edward D.; Ross, John

    1992-01-01

    With methods developed in a prior article on the chemical kinetic implementation of a McCulloch-Pitts neuron, connections among neurons, logic gates, and a clocking mechanism, we construct examples of clocked finite-state machines. These machines include a binary decoder, a binary adder, and a stack memory. An example of the operation of the binary adder is given, and the chemical concentrations corresponding to the state of each chemical neuron are followed in time. Using these methods, we can, in principle, construct a universal Turing machine, and these chemical networks inherit the halting problem

  8. Secondary structural analysis of proteins based on 13C chemical shift assignments in unresolved solid-state NMR spectra enhanced by fragmented structure database

    International Nuclear Information System (INIS)

    Magic-angle-spinning solid-state 13C NMR spectroscopy is useful for structural analysis of non-crystalline proteins. However, the signal assignments and structural analysis are often hampered by the signal overlaps primarily due to minor structural heterogeneities, especially for uniformly-13C,15N labeled samples. To overcome this problem, we present a method for assigning 13C chemical shifts and secondary structures from unresolved two-dimensional 13C–13C MAS NMR spectra by spectral fitting, named reconstruction of spectra using protein local structures (RESPLS). The spectral fitting was conducted using databases of protein fragmented structures related to 13Cα, 13Cβ, and 13C′ chemical shifts and cross-peak intensities. The experimental 13C–13C inter- and intra-residue correlation spectra of uniformly isotope-labeled ubiquitin in the lyophilized state had a few broad peaks. The fitting analysis for these spectra provided sequence-specific Cα, Cβ, and C′ chemical shifts with an accuracy of about 1.5 ppm, which enabled the assignment of the secondary structures with an accuracy of 79 %. The structural heterogeneity of the lyophilized ubiquitin is revealed from the results. Test of RESPLS analysis for simulated spectra of five different types of proteins indicated that the method allowed the secondary structure determination with accuracy of about 80 % for the 50–200 residue proteins. These results demonstrate that the RESPLS approach expands the applicability of the NMR to non-crystalline proteins exhibiting unresolved 13C NMR spectra, such as lyophilized proteins, amyloids, membrane proteins and proteins in living cells.

  9. Microprocessors in automatic chemical analysis

    International Nuclear Information System (INIS)

    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

  10. Chemical substructure analysis in toxicology

    International Nuclear Information System (INIS)

    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

  11. 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.

  12. Chemical reaction systems with toric steady states

    CERN Document Server

    Millan, Mercedes Perez; Shiu, Anne; Conradi, Carsten

    2011-01-01

    Mass-action chemical reaction systems are frequently used in Computational Biology. The corresponding polynomial dynamical systems are often large, consisting of tens or even hundreds of ordinary differential equations, and poorly parameterized (due to noisy measurement data and a small number of data points and repetitions). Therefore, it is often difficult to establish the existence of (positive) steady states or to determine whether more complicated phenomena such as multistationarity exist. If, however, the steady state ideal of the system is a binomial ideal, then we show that these questions can be answered easily. The focus of this work is on systems with this property, and we say that such systems have toric steady states. Our main result gives sufficient conditions for a chemical reaction system to have toric steady states. Furthermore, we analyze the capacity of such a system to exhibit positive steady states and multistationarity. Examples of systems with toric steady states include weakly-reversib...

  13. Validation of a CATHENA fuel channel model for the post blowdown analysis of the high temperature thermal-chemical experiment CS28-1, I - Steady state

    International Nuclear Information System (INIS)

    To form a licensing basis for the new methodology of the fuel channel safety analysis code system for CANDU-6, a CATHENA model for the post-blowdown fuel channel analysis for a Large Break LOCA has been developed, and tested for the steady state of a high temperature thermal-chemical experiment CS28-1. As the major concerns of the post-blowdown fuel channel analysis of the current CANDU-6 design are how much of the decay heat can be discharged to the moderator via a radiation and a convective heat transfer at the expected accident conditions, and how much zirconium sheath would be oxidized to generate H2 at how high a fuel temperature, this study has focused on understanding these phenomena, their interrelations, and a way to maintain a good accuracy in the prediction of the fuel and the pressure tube temperatures without losing the important physics of the involved phenomena throughout the post-blowdown phase of a LBLOCA. For a better prediction, those factors that may significantly contribute to the prediction accuracy of the steady state of the test bundles were sought. The result shows that once the pressure tube temperature is predicted correctly by the CATHENA heat transfer model between the pressure tube and the calandria tube through a gap thermal resistance adjustment, all the remaining temperatures of the inner ring, middle ring and outer ring FES temperatures can be predicted quite satisfactorily, say to within an accuracy range of 20-25 deg. C, which is comparable to the reported accuracy of the temperature measurement, ±2%. Also the analysis shows the choice of the emissivity of the solid structures (typically, 0.80, 0.34, 0.34 for FES, PT, CT), and the thermal resistance across the CO2 annulus are factors that significantly affect the steady state prediction accuracy. A question on the legitimacy of using 'transparent' assumption for the CO2 gas annulus for the radiation heat transfer between the pressure tube and the calandria tube in CATHENA code

  14. Detection of uranium and chemical state analysis of individual radioactive microparticles emitted from the Fukushima nuclear accident using multiple synchrotron radiation X-ray analyses.

    Science.gov (United States)

    Abe, Yoshinari; Iizawa, Yushin; Terada, Yasuko; Adachi, Kouji; Igarashi, Yasuhito; Nakai, Izumi

    2014-09-01

    Synchrotron radiation (SR) X-ray microbeam analyses revealed the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, resulting in better understanding of what occurred in the plant during the early stages of the accident. Three spherical microparticles (∼2 μm, diameter) containing radioactive Cs were found in aerosol samples collected on March 14th and 15th, 2011, in Tsukuba, 172 km southwest of the FDNPP. SR-μ-X-ray fluorescence analysis detected the following 10 heavy elements in all three particles: Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba. In addition, U was found for the first time in two of the particles, further confirmed by U L-edge X-ray absorption near-edge structure (XANES) spectra, implying that U fuel and its fission products were contained in these particles along with radioactive Cs. These results strongly suggest that the FDNPP was damaged sufficiently to emit U fuel and fission products outside the containment vessel as aerosol particles. SR-μ-XANES spectra of Fe, Zn, Mo, and Sn K-edges for the individual particles revealed that they were present at high oxidation states, i.e., Fe(3+), Zn(2+), Mo(6+), and Sn(4+) in the glass matrix, confirmed by SR-μ-X-ray diffraction analysis. These radioactive materials in a glassy state may remain in the environment longer than those emitted as water-soluble radioactive Cs aerosol particles. PMID:25084242

  15. Chemical Analysis of Suspected Unrecorded Alcoholic Beverages from the States of São Paulo and Minas Gerais, Brazil.

    Science.gov (United States)

    Negri, Giuseppina; Soares Neto, Julino Assunção Rodrigues; de Araujo Carlini, Elisaldo Luiz

    2015-01-01

    Our study analyzed 152 samples of alcoholic beverages collected from the states of São Paulo and Minas Gerais, Brazil, using gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FT-IR), and inductively coupled plasma atomic emission spectrometry (ICP-AES). The methanol content varied from 20 to 180 ppm in 28 samples, and the limit of the accepted level of 200 ppm was exceeded in only one sample. High content of cyanide derivatives and ethyl carbamate, above the accepted level of 150 ppb, was observed in 109 samples. Carbonyl compounds were also observed in 111 samples, showing hydroxy 2-propanone, 4-methyl-4-hepten-3-one, furfural, and 2-hydroxyethylcarbamate as main constituents. Copper was found at concentrations above 5 ppm in 26 samples; the maximum value observed was 28 ppm. This work evaluated the human health risk associated with the poor quality of suspected unrecorded alcohols beverages. PMID:26495155

  16. Chemical Analysis of Suspected Unrecorded Alcoholic Beverages from the States of São Paulo and Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Giuseppina Negri

    2015-01-01

    Full Text Available Our study analyzed 152 samples of alcoholic beverages collected from the states of São Paulo and Minas Gerais, Brazil, using gas chromatography with flame ionization detection (GC-FID and mass spectrometry (GC-MS, Fourier transform infrared spectroscopy (FT-IR, and inductively coupled plasma atomic emission spectrometry (ICP-AES. The methanol content varied from 20 to 180 ppm in 28 samples, and the limit of the accepted level of 200 ppm was exceeded in only one sample. High content of cyanide derivatives and ethyl carbamate, above the accepted level of 150 ppb, was observed in 109 samples. Carbonyl compounds were also observed in 111 samples, showing hydroxy 2-propanone, 4-methyl-4-hepten-3-one, furfural, and 2-hydroxyethylcarbamate as main constituents. Copper was found at concentrations above 5 ppm in 26 samples; the maximum value observed was 28 ppm. This work evaluated the human health risk associated with the poor quality of suspected unrecorded alcohols beverages.

  17. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations, Part I: Chemical shifts assignment.

    Science.gov (United States)

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika Agnieszka; Szeleszczuk, Łukasz; Wawer, Iwona

    2016-04-15

    Solid-state NMR is an excellent and useful method for analyzing solid-state forms of drugs. In the (13)C CP/MAS NMR spectra of the solid dosage forms many of the signals originate from the excipients and should be distinguished from those of active pharmaceutical ingredient (API). In this work the most common pharmaceutical excipients used in the solid drug formulations: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. Their (13)C CP/MAS NMR spectra were recorded and the signals were assigned, employing the results (R(2): 0.948-0.998) of GIPAW calculations and theoretical chemical shifts. The (13)C ssNMR spectra for some of the studied excipients have not been published before while for the other signals in the spectra they were not properly assigned or the assignments were not correct. The results summarize and complement the data on the (13)C ssNMR analysis of the most common pharmaceutical excipients and are essential for further NMR studies of API-excipient interactions in the pharmaceutical formulations. PMID:26845204

  18. On inverse methods for combining chemical and physical oceanographic data: A steady-state analysis of the Atlantic Ocean

    International Nuclear Information System (INIS)

    An attempt has been made to increase the spatial resolution in the vise of inverse methods to deduce rates of water circulation and detritus formation by the simultaneous use of tracer data and the condition of quasi-geostrophic flow. It is shown that an overdetermined system of equations is desirable to permit analysis of the sensitivity of a solution to errors in the data fields. The method has been tested for the Atlantic Ocean, in which case we employ an 84-box model (eight layers in the vertical and 12 regions in the horizontal define the box configuration). As quasi-steady tracers we consider dissolved inorganic carbon (DIC), radiocarbon, alkalinity, phosphorus, oxygen, salinity and enthalpy. The condition of quasi-geostrophic flow is employed for flow across all vertical surfaces between regions except close to the equator. Water continuity is required to be exactly satisfied by the use of a set of closed loops to describe the advective flow. The method of least squares is used to derive a solution and in . . so doing we also require, that turbulence only transfers matter down tracer gradients (i.e. eddy diffusivity is nonnegative) and that detritus is formed only in surface boxes and is destroyed in the water column below. It is shown how appropriate weighting of the equations in the set is decisive for the solutions that we derive and that great care must be taken to ascertain that the interior tracer distributions and the boundary conditions in terms of exchange of tracer material with the exterior are compatible. The enthalpy equations turn out not to fulfil such a demand and have not been used in deriving the solutions presented in the paper. A basic solution with an ageostrophic flow component of about 15% is derived and compared with current knowledge about the general circulation of the Atlantic Ocean and the rates of detritus formation and destruction. The sensitivity of the solution to uncertainties in the data field is presented. It is shown that

  19. Entropy generation reduction through chemical pinch analysis

    International Nuclear Information System (INIS)

    The pinch analysis (PA) concept emerged, late '80s, as one of the methods to address the energy management in the new era of sustainable development. It was derived from combined first and second law analysis, as a technique ensuring a better thermal integration, aiming the minimization of entropy production or, equivalently, exergy destruction by heat exchanger networks (HEN). Although its ascendance from the second law analysis is questionable, the PA reveals as a widespread tool, nowadays, helping in energy savings mostly through a more rational use of utilities. Unfortunately, as principal downside, one should be aware that the global minimum entropy production is seldom attained, since the PA does not tackle the whole plant letting aside the chemical reactors or separation trains. The chemical reactor network (CRN) is responsible for large amounts of entropy generation (exergy losses), mainly due to the combined composition and temperature change. The chemical pinch analysis (CPA) concept focuses on, simultaneously, the entropy generation reduction of both CRN and HEN, while keeping the state and working parameters of the plant in the range of industrial interest. The fundamental idea of CPA is to include the CRN (through the chemical reaction heat developed in reactors) into the HEN and to submit this extended system to the PA. This is accomplished by replacing the chemical reactor with a virtual heat exchanger system producing the same amount of entropy. For an endothermic non-adiabatic chemical reactor, the (stepwise infinitesimal) supply heat δq flows from a source (an external/internal heater) to the stream undergoing the chemical transformation through the reactor, which in turn releases the heat of reaction ΔHR to a virtual cold stream flowing through a virtual cooler. For an exothermic non-adiabatic chemical reactor, the replacement is likewise, but the heat flows oppositely. Thus, in the practice of designing or retrofitting a flowsheet, in order to

  20. Chemical State Mapping of Degraded B4C Control Rod Investigated with Soft X-ray Emission Spectrometer in Electron Probe Micro-analysis

    Science.gov (United States)

    Kasada, R.; Ha, Y.; Higuchi, T.; Sakamoto, K.

    2016-05-01

    B4C is widely used as control rods in light water reactors, such as the Fukushima Daiichi nuclear power plant, because it shows excellent neutron absorption and has a high melting point. However, B4C can melt at lower temperatures owing to eutectic interactions with stainless steel and can even evaporate by reacting with high-temperature steam under severe accident conditions. To reduce the risk of recriticality, a precise understanding of the location and chemical state of B in the melt core is necessary. Here we show that a novel soft X-ray emission spectrometer in electron probe microanalysis can help to obtain a chemical state map of B in a modeled control rod after a high-temperature steam oxidation test.

  1. Chemical State Mapping of Degraded B4C Control Rod Investigated with Soft X-ray Emission Spectrometer in Electron Probe Micro-analysis.

    Science.gov (United States)

    Kasada, R; Ha, Y; Higuchi, T; Sakamoto, K

    2016-01-01

    B4C is widely used as control rods in light water reactors, such as the Fukushima Daiichi nuclear power plant, because it shows excellent neutron absorption and has a high melting point. However, B4C can melt at lower temperatures owing to eutectic interactions with stainless steel and can even evaporate by reacting with high-temperature steam under severe accident conditions. To reduce the risk of recriticality, a precise understanding of the location and chemical state of B in the melt core is necessary. Here we show that a novel soft X-ray emission spectrometer in electron probe microanalysis can help to obtain a chemical state map of B in a modeled control rod after a high-temperature steam oxidation test. PMID:27161666

  2. Chemical states of molybdenum in radioactive waste glass

    International Nuclear Information System (INIS)

    In order to confirm an expectation that the chemical state of molybdenum in glass reflects the phase separation tendency of the yellow solid from the melt of borosilicate glass, simulated waste glasses were prepared, and ESCA analysis was performed using a commercially available electron spectrometer (PHI550 E) with an excitation source consisting of Mg Kα-ray. The effects of the concentration of Mo and FE2O3 and the melting atmosphere (oxidizing or reducing) in which the samples were prepared on the chemical state of Mo and the solubility of MoO3 were examined. From the observation of Mo spectra, it was shown that Mo in waste glass had several valencies, e.g., Mo(3), Mo(4), Mo(5) and Mo(6), while Mo in the yellow solid separated from the melts exhibited hexa-valent state, the peak intensity of higher valencies increased relatively with the increase of MoO3 concentration, but the chemical state of Mo did not change remarkably around the solubility limit of MoO3, the melting atmosphere influenced on the Mo state in the waste glass, the peak intensity of Mo(6) increased relatively with the increasing Fe2O3 concentration, and Mo in devitrified glass exhibited hexa-valent state. (Yoshitake, I.)

  3. Comparison among chemical, mineralogical and physical analysis from alluvial clays from counties of Southwest of Minas Gerais state (Brazil); Comparacao entre as analises quimicas, mineralogicas e tecnologicas das argilas aluvionares de alguns municipios do sudoeste de Minas Gerais

    Energy Technology Data Exchange (ETDEWEB)

    Gaspar Junior, L.A., E-mail: lineo.gaspar@unifal-mg.edu.br [Universidade Federal de Alfenas (UNIALFENAS), MG (Brazil). Instituto de Ciencias da Natureza; Varajao, A.F.D.C. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Escola de Minas; Souza, M.H.O. [Universidade Federal de Uberlandia (UFU), MG (Brazil). Departamento de Geografia; Moreno, M.M.T. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Rio Claro, SP (Brazil). Departamento de Petrologia e Metalogenia

    2011-07-01

    The studied area is located in the southwestern portion of Minas Gerais State, encompassing the counties of Alfenas, Areado, Machado, Poco Fundo, Campestre, Serrania, Monte Belo, Bandeira do Sul, Botelhos and Cabo Verde. This region is dominated by strongly weathered pre-cambrian rocks in association with colluvial-alluvial sediments. The present work consisted in a comparison among the mineralogical (X-Ray Diffraction), textural (Laser Granulometry), chemical (X-Ray Fluorescence) and technological (mechanical resistance, water absorption, etc, made in specimen tests) properties of the clays collected on potteries located in these counties. The mineralogical and chemical analysis displayed the kaolinitic nature of the clays from this region, showing also small amount of interlayered clays and large amount of quartz. The best results of physical analysis were obtained for clays from the counties of Cabo Verde and Monte Belo due to the presence of lower values of SiO{sub 2} (quartz) associated with a finer particle size distribution. (author)

  4. Characterization of Surface Chemical States of a Thick Insulator: Chemical State Imaging on MgO Surface

    Science.gov (United States)

    Yi, Yeonjin; Cho, Sangwan; Noh, Myungkeun; Whang, Chung-Nam; Jeong, Kwangho; Shin, Hyun-Joon

    2005-02-01

    We report a surface characterization tool that can be effectively used to investigate the chemical state and subtle radiation damage on a thick insulator surface. It has been used to examine the MgO surface of a plasma display panel (PDP) consisting of a stack of insulator layers of approximately 51 μm thickness on a 2-mm-thick glass plate. The scanning photoelectron microscopy (SPEM) image of the insulating MgO surface was obtained by using the difference in Au 4f peak shift due to the surface charging at each pixel, where a Au adlayer of approximately 15 {\\AA} thickness was formed on the surface to overcome the serious charging shift of the peak position and the spectral deterioration in the photoelectron spectra. The observed contrast in the SPEM image reveals the chemical modification of the underlying MgO surface induced by the plasma discharge damage. The chemical state analysis of the MgO surface was carried out by comparing the Mg 2p, C 1s and O 1s photoemission spectra collected at each pixel of the SPEM image. We assigned four suboxide phases, MgO, MgCO3, Mg(OH)2 and Mg1+, on the initial MgO surface, where the Mg(OH)2 and Mg1+ phases vanished rapidly as the discharge-induced surface damage began.

  5. Chemical states in XPS and Raman analysis during removal of Cr(VI) from contaminated water by mixed maghemite–magnetite nanoparticles

    International Nuclear Information System (INIS)

    Highlights: ► Cr(VI) adsorption on mixed maghemite–magnetite is spontaneous and endothermic. ► Theoretical multiplet analysis shows that during Cr adsorption, the amount of maghemite increases (from 70 to 89%). ► Fe(II) was transformed into Fe(III) by the redox reaction. ► Cr(VI) species were reduced to Cr(III) species on the mixed maghemite–magnetite. - Abstract: Mixed maghemite–magnetite has been used as adsorbent for Cr(VI) removal in this study. Results show that the adsorption capacity is enhanced with an increase in reaction temperature and decrease in free energy change. Thermodynamic study shows that Cr(VI) adsorption on the mixed maghemite and magnetite is endothermic in nature and is dependent on solution pH between 3 and 6. X-ray photoelectron spectroscopy (XPS) results demonstrate the theoretical multiplet peaks for iron and chromium adsorbed iron at the surface of the γ-Fe2O3 and Fe3O4 mixture. Theoretical multiplet analysis shows that during Cr adsorption, the amount of maghemite increases (from 70 to 89%). In magnetite spectra, the relative content of Fe(II) decreases from 8.2 to 3.6% indicating the reduction of magnetite in the mixture particles. In Raman spectroscopy studies, clear peaks of chromium on iron oxide were generated at 826 cm−1, which could be attributed to chemical interactions between chromium compound and iron oxide. From the results of Raman and XPS studies, electrostatic attraction and oxidation–reduction between chromium and mixed maghemite–magnetite are postulated as mechanisms for the removal of Cr(VI) from aqueous solutions.

  6. Possibilities of Moessbauer spectroscopy for chemical analysis

    International Nuclear Information System (INIS)

    Full text: The Moessbauer spectroscopy technique belongs to few methods of defining the phase state or crystallographic sites of a substance. The Moessbauer spectra bear information on various hyperfine interactions, many of which are indirectly related to the chemical nature of the Moessbauer atom and its nearest environment. Determination of the parameters of hyperfine interactions that can be extracted from Moessbauer spectra and used for qualitative analysis is a routine task. In the present work, we studied the influence of various factors on experimental errors encountered in quantitatively defining the phase composition or site populations of the substance under study, such as the measurements geometry, Lamb-Moessbauer coefficients, absorber thickness, efficiency and dead time of the detection system and spectral line shape. The absolute f measurements were made using the 'black' absorber method. Moessbauer measurements were carried out with carefully controlled background intensities, since the accuracy of f evaluation directly depends on the measurement of the background. The influence of a non-uniformity of samples on the results of the quantitative analysis is discussed. The data analysis was divided into two parts: removal of instrumental artifacts by folding and baseline correction and deconvolution to extract the hyperfine parameters of individual local environments. In our approach, calibration graphs were drawn by measuring the spectra of a series of analogous samples having different known concentrations. For the same purpose, the internal standard method was also used. Experimental data are presented for phase analyses of different samples. (author)

  7. Chemical characterization of bottom sediments from Ribeira de Iguape river, Parana and Sao Paulo states, Brazil, by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    During several decades the Alto Vale of Ribeira region (SP-PR) suffered under lead mining activities in the region. Although in 1996 all such activities ceased, the mining activities left behind a huge amount of environmental liabilities mainly in the hydrographic basin of Ribeira de Iguape river. In the present study the chemical characterization of bottom sediments was undertaken and the concentration of the major (Ca, Fe, K and Na), trace (As, Ba, Br, Co, Cs, Hf, Rb, Sb, Ta, Th, U, Zn) and rare earth elements (La, Ce, Eu, Nd, Sm, Lu, Tb, Yb and Sc) by instrumental neutron activation analysis (INAA) were determined. The validation of the analytical methodology was performed by means of certified reference materials analyses and Z-score criterion was used. Eight points were sampled at the Ribeira de Iguape river and its majorities from Adrianopolis (Pr) (site 01) to Registro (SP) (site 08). Granulometric analyses and textural classification were undertaken in the sediment samples. The results obtained by using INAA were compared to UCC (Upper Continental Crust) reference values. The environmental tools of Enrichment Factor (EF) and Geochemical Index (GI) were used to assess the degree of metal contamination in the sediment samples. Samples from site 5 (Betari river - Iporanga, SP) presented high values for As, Sb and Zn and greater IGeo (3.1 - 5.5) and EF (>7.0) values for these elements classifying this point as highly polluted for these elements as well as a strong anthropogenic contribution. Site 7 (Ribeira river - Eldorado, SP) was considered moderately polluted for As, Br and Sb. The high concentration levels of some metals and metalloids reflect the contribution of mining activities from the past in the region. From the results it can be seen that although mining activities no longer exist since 1996, the deleterious effects in the environment are still present and strong. (author)

  8. Homemade chemical bomb incidents - 15 states, 2003-2011.

    Science.gov (United States)

    2013-06-21

    Homemade chemical bombs (HCBs) are made from commonly found chemicals. The volume of news reports of HCB explosions suggests they are not uncommon. To determine the number of events involving HCBs in the United States and describe the factors associated with them, the Agency for Toxic Substances and Disease Registry (ATSDR) analyzed data from its surveillance system that tracks spills and leaks of hazardous substances. This report describes the results of that analysis, which indicated that, during 2003-2011, a total of 134 events involving HCBs were reported from 15 states. Among those events, 21 (16%) resulted in adverse health effects (i.e., respiratory symptoms, burns, and skin irritation) for 53 persons. The majority (35 [66%]) of these persons were youths.HCBs are hazardous and especially dangerous if detonated in public areas. Increasing awareness of HCBs and their dangers (particularly during summer months) among first-responders, parents, school staff members and others who work with youths might help reduce injuries associated with HCBs. PMID:23784014

  9. Chemical analysis of water in hydrogeology

    International Nuclear Information System (INIS)

    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.

  10. The State of Chemical Pollution in Kenya

    International Nuclear Information System (INIS)

    The review draws attention to natural or biological sources of chemical release into the atmosphere. The magnitude of such a release may sometimes be higher than chemicals released into the environment by man's activities. Measurements of CO2, CH4, SO4=,Cl-, pH and O3 (please note that, the numerals are supposed to be under the alphabet formulas) concentrations in the Kenyan atmosphere reveal that the first two and last compounds are at the globally accepted concentration levels. The rest are below the world accepted levels. However more research is needed in measurement of atmospheric constituents. The determination of heavy metals concentrations in water, sediments, plants and fish reveal that sediments have the highest level of any concentration followed by plants, fish and water. The source of the metals in water and fish is mainly geological. However, higher concentrations of these metals in and around industrial centres have been noted. In all cases the concentration of metals Mn,Fe,Cu,Zn,Cd, Hg and Pb in water and fish are below the FAO/WHO recommended maxium units. Measurement of fluoride content in borehole water, rivers and lakes in Kenya show that, 21% of 865 borholes have a high concentration of fluorides. Kerio River also has a high content of fluoride and all lakes except for Naivasha and Victoria have nitrate content between 6.1 and 6.6. ppm. The nitrite content was undetected in all rivers and only 2 boreholes waters had nitrate content above 62 ppm (Author)

  11. The chemical state of complex uranium oxides

    OpenAIRE

    Kvashnina, K. O.; Butorin, S. M.; Martin, P.; P. Glatzel

    2013-01-01

    We report here the first direct observation of U(V) in uranium binary oxides and analyze the gradual conversion of the U oxidation state in the mixed uranium systems. Our finding clarifies previous contradicting results and provides important input for the geological disposal of spent fuel, recycling applications and chemistry of uranium species.

  12. 40 CFR 761.253 - Chemical analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical analysis. 761.253 Section 761.253 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT... analysis. (a) Extract PCBs from the standard wipe sample collection medium and clean-up the extracted...

  13. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    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

  14. Spectroscopic chemical analysis methods and apparatus

    Science.gov (United States)

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

    2013-01-01

    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. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection 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.

  15. Service activities of chemical analysis division

    International Nuclear Information System (INIS)

    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)

  16. Nevada state revenues analysis

    International Nuclear Information System (INIS)

    This report analyzes the major sources of revenue to the Nevada State General Fund for purposes of estimating impacts associated with the siting of a nuclear waste repository at Yucca Mountain in Nye County, Nevada. Each major revenue source is analyzed to identify relationships among the economic or demographic base, the revenue base, and the revenues generated. Trends and changes in the rates and/or base are highlighted. A model is developed for each revenue source to allow impact estimation

  17. Reaction diffusion and solid state chemical kinetics handbook

    CERN Document Server

    Dybkov, V I

    2010-01-01

    This monograph deals with a physico-chemical approach to the problem of the solid-state growth of chemical compound layers and reaction-diffusion in binary heterogeneous systems formed by two solids; as well as a solid with a liquid or a gas. It is explained why the number of compound layers growing at the interface between the original phases is usually much lower than the number of chemical compounds in the phase diagram of a given binary system. For example, of the eight intermetallic compounds which exist in the aluminium-zirconium binary system, only ZrAl3 was found to grow as a separate

  18. Ab initio and DFT analysis of the low-lying electronic states of metal dihalides: quantum chemical calculations on the neutral BrMCl (M = Cu, Ag, Au).

    Science.gov (United States)

    Atsumi, Michiko; Lindh, Roland; González, Leticia; Gourlaouen, Christophe; Daniel, Chantal

    2013-07-01

    The electronic configuration of the electronic ground and low-lying doublet excited states of neutral metal dihalides BrMCl (M = Cu, Ag, Au) has been investigated on the basis of CASSCF/CASPT2 methods taking into account scalar relativistic effects. A preliminary study of the electronic problem in BrAgCl, based on DFT and CASSCF/CASPT2 approaches and using various basis sets, namely relativistic all-electron basis sets, effective core potentials and ab initio model potentials (AIMP), as well as non-relativistic AIMP is discussed. It is shown that single-determinant methods are not flexible enough to describe the bonding of the neutral species in the electronic ground state regardless of the basis set. The failure to allocate the single electron of BrAgCl correlates with a wrong charge distribution within the complex, which is more accentuated when using pseudopotential basis sets. The inclusion of static and dynamic correlation effects by means of CASSCF/CASPT2 methods using large relativistic all-electron basis sets provides a correct qualitative picture of the electronic structure of the BrMCl series (M = Cu, Ag, Au). The spin unrestricted KS-DFT approach leads to a reasonable description of the degenerate electronic ground state ((2)Σ/(2)Π) bonding in these complexes with negligible spin contamination providing comparative spin densities in the series of molecules under investigation. PMID:23632776

  19. Chemical abundance analysis of 19 barium stars

    CERN Document Server

    Yang, G C; Spite, M; Chen, Y Q; Zhao, G; Zhang, B; Liu, G Q; Liu, Y J; Liu, N; Deng, L C; Spite, F; Hill, V; Zhang, C X

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures, surface gravities, metallicity and microturbulent velocity) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their light elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn and Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-ca...

  20. On the steady states of weakly reversible chemical reaction networks

    OpenAIRE

    Deng, Jian; Jones, Christopher; Feinberg, Martin; Nachman, Adrian

    2011-01-01

    A natural condition on the structure of the underlying chemical reaction network, namely weak reversibility, is shown to guarantee the existence of an equilibrium (steady state) in each positive stoichiometric compatibility class for the associated mass-action system. Furthermore, an index formula is given for the set of equilibria in a given stoichiometric compatibility class.

  1. Analysis of Chemical Technology Division waste streams

    International Nuclear Information System (INIS)

    This document is a summary of the sources, quantities, and characteristics of the wastes generated by the Chemical Technology Division (CTD) of the Oak Ridge National Laboratory. The major contributors of hazardous, mixed, and radioactive wastes in the CTD as of the writing of this document were the Chemical Development Section, the Isotopes Section, and the Process Development Section. The objectives of this report are to identify the sources and the summarize the quantities and characteristics of hazardous, mixed, gaseous, and solid and liquid radioactive wastes that are generated by the Chemical Technology Division (CTD) of the Oak Ridge National Laboratory (ORNL). This study was performed in support of the CTD waste-reduction program -- the goals of which are to reduce both the volume and hazard level of the waste generated by the division. Prior to the initiation of any specific waste-reduction projects, an understanding of the overall waste-generation system of CTD must be developed. Therefore, the general approach taken in this study is that of an overall CTD waste-systems analysis, which is a detailed presentation of the generation points and general characteristics of each waste stream in CTD. The goal of this analysis is to identify the primary waste generators in the division and determine the most beneficial areas to initiate waste-reduction projects. 4 refs., 4 figs., 13 tabs

  2. Chemical detection, identification, and analysis system

    International Nuclear Information System (INIS)

    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

  3. NEXAFS Chemical State and Bond Lengths of p-Aminobenzoic Acid in Solution and Solid State

    Science.gov (United States)

    Stevens, J. S.; Gainar, A.; Suljoti, E.; Xiao, J.; Golnak, R.; Aziz, E. F.; Schroeder, S. L. M.

    2016-05-01

    Solid-state and solution pH-dependent NEXAFS studies allow direct observation of the electronic state of para-aminobenzoic acid (PABA) as a function of its chemical environment, revealing the chemical state and bonding of the chemical species. Variations in the ionization potential (IP) and 1s→π* resonances unequivocally identify the chemical species (neutral, cationic, or anionic) present and the varying local environment. Shifts in σ* shape resonances relative to the IP in the NEXAFS spectra vary with C-N bond length, and the important effect of minor alterations in bond length is confirmed with nitrogen FEFF calculations, leading to the possibility of bond length determination in solution.

  4. Physico-chemical studies on samarium soaps in solid state

    International Nuclear Information System (INIS)

    The physico-chemical characteristics of samarium soaps (caproate and caprate) in solid state were investigated by IR, X-ray diffraction and TGA measurements. The IR results revealed that the fatty acids exist in dimeric state through hydrogen bonding and samarium soaps possess partial ionic character. The X-ray diffraction measurements were used to calculate the long spacings and the results confirmed the double layer structure of samarium soaps. The decomposition reaction was found kinetically of zero order and the values of energy of activation for the decomposition process for caproate and caprate were found to be 8,0 and 7,8 kcal mol-1, respectively. (Authors)

  5. 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...

  6. Chemical protective clothing - State of the art and the future

    International Nuclear Information System (INIS)

    Clothing used to protect the skin from exposure to chemicals (CPC) is an integral part of many work-places. Only 10-15 years ago the strategy behind selecting CPC to afford this protection was to find a type of CPC which was essentially liquid-proof and would therefore protect the skin from exposure to a liquid chemical. However, in the last 10 years there has been an explosion of data in the industrial hygiene field related to the permeation of chemical protective clothing by liquid chemicals. These data indicate clearly that when CPC is exposed to a chemical, it may not disintegrate or degrade, but nevertheless, will be permeated by the chemical and the skin will be exposed. This has led to a new strategy for selecting CPC which essentially assumes that any exposure of the skin is harmful. Consequently, a worst-case scenario is assumed when selecting CPC and often the garment with the best permeation properties is selected regardless of cost. This philosophy is prompted by a lack of knowledge concerning the skin and how it is permeated by industrial chemicals in their liquid and vapor states. The interests in the last 10 years in CPC has led to new developments and an exciting future for protective clothing. Several new laminated polymeric materials are now being used in both gloves and full-body suits. These polymers are plastic rather than elastomeric and therefore do not afford good dexterity properties. However, their permeability properties are extremely good. In addition, further research on dermal penetration should give the industrial hygienist the necessary information to perform risk assessments for skin exposure. These new risk assessment strategies should negate the current need to overprotect workers. Overprotection often leads to unnecessary costs and can lead to increased stress on the worker in the form of heat stress

  7. Iron-based syngas chemical looping process and coal-direct chemical looping process development at Ohio State University

    International Nuclear Information System (INIS)

    Highlights: • Moving bed reducer maximizes solids conversion and maintains full fuel conversion. • 850+ Operating hours completed in 25-kWth sub-pilot chemical looping units. • Full solid and gaseous fuel conversion achieved in sub-pilot chemical looping units. • Fully integrated, pressurized 250-kWth pilot SCL unit construction initiated. • Extensive techno-economic analysis performed on CDCL and SCL process configurations. - Abstract: The increasing demands for energy and concern of global warming are intertwined issues of critical importance. With the pressing need for clean, efficient, and cost-effective energy conversion processes, the chemical looping strategy has evolved as a promising alternative to the traditional carbonaceous fuel conversion processes. Chemical looping processes utilize oxygen carrier particles to indirectly convert carbonaceous fuels while capturing CO2 for sequestration and/or utilization. Throughout its development, multiple oxygen carrier compositions and reactor configurations have been studied and demonstrated. The Ohio State University (OSU) chemical looping technologies have received significant attention over the recent years. OSU’s unique moving-bed chemical looping technologies coupled with iron-based oxygen carrier particles capable of sustaining hundreds of redox cycles have the advantage of converting a variety of carbonaceous fuels, such as natural gas, coal and biomass, to electricity, H2, liquid fuels, or any combination thereof with zero to negative net CO2 emissions. Specifically, two chemical looping processes are being developed and studied, the syngas chemical looping (SCL) and the coal direct chemical looping (CDCL) technologies. Over the past 14 years, these processes have developed from a novel concept to successful sub-pilot (25 kWth) demonstrations. With the support of the Advanced Research Projects Agency – Energy (ARPA-E) of the US Department of Energy (USDOE), a 250 kWth high pressure SCL pilot

  8. Surface chemical states of barium zirconate titanate thin films prepared by chemical solution deposition

    International Nuclear Information System (INIS)

    Ba(Zr0.05Ti0.95)O3 (BZT) thin films grown on Pt/Ti/SiO2/Si(1 0 0) substrates were prepared by chemical solution deposition. The structural and surface morphology of BZT thin films has been studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the random oriented BZT thin film grown on Pt/Ti/SiO2/Si(1 0 0) substrate with a perovskite phase. The SEM surface image showed that the BZT thin film was crack-free. And the average grain size and thickness of the BZT film are 35 and 400 nm, respectively. Furthermore, the chemical states and chemical composition of the films were determined by X-ray photoelectron spectroscopy (XPS) near the surface. The XPS results show that Ba, Ti, and Zr exist mainly in the forms of BZT perovskite structure.

  9. State waste discharge permit application, 200-E chemical drain field

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect ground would be subject to permitting under the structure of Chapter 173-216 (or 173-218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE 91NM-177, (Ecology and DOE-RL 1991). The Consent Order No. DE 91NM-177 requires a series of permitting activities for liquid effluent discharges. This document presents the State Waste Discharge Permit (SWDP) application for the 200-E Chemical Drain Field. Waste water from the 272-E Building enters the process sewer line directly through a floor drain, while waste water from the 2703-E Building is collected in two floor drains, (north and south) that act as sumps and are discharged periodically. The 272-E and 2703-E Buildings constitute the only discharges to the process sewer line and the 200-E Chemical Drain Field.

  10. State waste discharge permit application, 200-E chemical drain field

    International Nuclear Information System (INIS)

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect ground would be subject to permitting under the structure of Chapter 173-216 (or 173-218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE 91NM-177, (Ecology and DOE-RL 1991). The Consent Order No. DE 91NM-177 requires a series of permitting activities for liquid effluent discharges. This document presents the State Waste Discharge Permit (SWDP) application for the 200-E Chemical Drain Field. Waste water from the 272-E Building enters the process sewer line directly through a floor drain, while waste water from the 2703-E Building is collected in two floor drains, (north and south) that act as sumps and are discharged periodically. The 272-E and 2703-E Buildings constitute the only discharges to the process sewer line and the 200-E Chemical Drain Field

  11. Implementation of REACH in the New Member States. Part one: Overview of the Chemical and Speciality Chemical Sector in the New Member States

    OpenAIRE

    Angerer, Gerhard; Sartorius, Christian; Nordbeck, Ralf; WOLF OLIVER; DELGADO SANCHO LUIS; LUO ZHENG

    2007-01-01

    This report informs about potential impacts of the European regulation concerning the registration, evaluation, authorisation and restriction of chemicals REACH (Regulation (EC) No 1907/2006) in the New Member States. It consists of two parts: 1) "Implementation of REACH in the New Member States – Part one: overview of the chemical and specialty chemical sector in the New Member States", and 2) "Implementation of REACH in the New Member States – Part two: Business case studies in se...

  12. 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.

  13. Applicability of federal and state hazardous waste regulatory programs to waste chemical weapons and chemical warfare agents.; TOPICAL

    International Nuclear Information System (INIS)

    This report reviews federal and state hazardous waste regulatory programs that govern the management of chemical weapons or chemical warfare agents. It addresses state programs in the eight states with chemical weapon storage facilities managed by the U.S. Army: Alabama, Arkansas, Colorado, Indiana, Kentucky, Maryland, Oregon, and Utah. It also includes discussions on 32 additional states or jurisdictions with known or suspected chemical weapons or chemical warfare agent presence (e.g., disposal sites containing chemical agent identification sets): Alaska, Arizona, California, Florida, Georgia, Hawaii, Idaho, Illinois, Iowa, Kansas, Louisiana, Massachusetts, Michigan, Mississippi, Missouri, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, the U.S. Virgin Islands, Virginia, Washington, Washington, D.C., and Wyoming. Resource Conservation and Recovery Act (RCRA) hazardous waste programs are reviewed to determine whether chemical weapons or chemical warfare agents are listed hazardous wastes or otherwise defined or identified as hazardous wastes. Because the U.S. Environmental Protection Agency (EPA) military munitions rule specifically addresses the management of chemical munitions, this report also indicates whether a state has adopted the rule and whether the resulting state regulations have been authorized by EPA. Many states have adopted parts or all of the EPA munitions rule but have not yet received authorization from EPA to implement the rule. In these cases, the states may enforce the adopted munitions rule provisions under state law, but these provisions are not federally enforceable

  14. Analysis of blood spots for polyfluoroalkyl chemicals

    International Nuclear Information System (INIS)

    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 (∼75 μL of blood) were -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-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.

  15. Principal Component Analysis on Chemical Abundances Spaces

    CERN Document Server

    Ting, Y S; Kobayashi, C; De Silva, G M; Bland-Hawthorn, J

    2011-01-01

    [Shortened] In preparation for the HERMES chemical tagging survey of about a million Galactic FGK stars, we estimate the number of independent dimensions of the space defined by the stellar chemical element abundances [X/Fe]. [...] We explore abundances in several environments, including solar neighbourhood thin/thick disk stars, halo metal-poor stars, globular clusters, open clusters, the Large Magellanic Cloud and the Fornax dwarf spheroidal galaxy. [...] We find that, especially at low metallicity, the production of r-process elements is likely to be associated with the production of alpha-elements. This may support the core-collapse supernovae as the r-process site. We also verify the over-abundances of light s-process elements at low metallicity, and find that the relative contribution decreases at higher metallicity, which suggests that this lighter elements primary process may be associated with massive stars. [...] Our analysis reveals two types of core-collapse supernovae: one produces mainly alpha-e...

  16. Advanced development in chemical analysis of Cordyceps.

    Science.gov (United States)

    Zhao, J; Xie, J; Wang, L Y; Li, S P

    2014-01-01

    Cordyceps sinensis, also called DongChongXiaCao (winter worm summer grass) in Chinese, is a well-known and valued traditional Chinese medicine. In 2006, we wrote a review for discussing the markers and analytical methods in quality control of Cordyceps (J. Pharm. Biomed. Anal. 41 (2006) 1571-1584). Since then this review has been cited by others for more than 60 times, which suggested that scientists have great interest in this special herbal material. Actually, the number of publications related to Cordyceps after 2006 is about 2-fold of that in two decades before 2006 according to the data from Web of Science. Therefore, it is necessary to review and discuss the advanced development in chemical analysis of Cordyceps since then. PMID:23688494

  17. Chemical abundance analysis of 19 barium stars

    Science.gov (United States)

    Yang, Guo-Chao; Liang, Yan-Chun; Spite, Monique; Chen, Yu-Qin; Zhao, Gang; Zhang, Bo; Liu, Guo-Qing; Liu, Yu-Juan; Liu, Nian; Deng, Li-Cai; Spite, Francois; Hill, Vanessa; Zhang, Cai-Xia

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe] >0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe] <0.54.

  18. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F.; Reid, Ray D.

    2012-01-01

    This invention relates to non-contact spectroscopic methods and apparatus for performing chemical analysis and the ideal wavelengths and sources needed for this analysis. It employs deep ultraviolet (200- to 300-nm spectral range) electron-beam-pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor lightemitting devices, and hollow cathode metal ion lasers. Three achieved goals for this innovation are to reduce the size (under 20 L), reduce the weight [under 100 lb (.45 kg)], and reduce the power consumption (under 100 W). This method can be used in microscope or macroscope to provide measurement of Raman and/or native fluorescence emission spectra either by point-by-point measurement, or by global imaging of emissions within specific ultraviolet spectral bands. In other embodiments, the method can be used in analytical instruments such as capillary electrophoresis, capillary electro-chromatography, high-performance liquid chromatography, flow cytometry, and related instruments for detection and identification of unknown analytes using a combination of native fluorescence and/or Raman spectroscopic methods. This design provides an electron-beampumped semiconductor radiation-producing method, or source, that can emit at a wavelength (or wavelengths) below 300 nm, e.g. in the deep ultraviolet between about 200 and 300 nm, and more preferably less than 260 nm. In some variations, the method is to produce incoherent radiation, while in other implementations it produces laser radiation. In some variations, this object is achieved by using an AlGaN emission medium, while in other implementations a diamond emission medium may be used. This instrument irradiates a sample with deep UV radiation, and then uses an improved filter for separating wavelengths to be detected. This provides a multi-stage analysis of the sample. To avoid the difficulties related to producing deep UV semiconductor sources, a pumping approach has been developed that uses

  19. Quantum-chemical study of electronically excited states ofprotolytic forms of vanillic acid

    OpenAIRE

    Vusovich, O. V.; Tchaikovskaya, O. N.; I. V. Sokolova; Vasileva, N. Y.

    2015-01-01

    The paper describes an analysis of possible ways of deactivation of electronically excited states of 4-hydroxy- 3-methoxy-benzoic acid (vanillic acid) and its protolytic forms with the use of quantum-chemical methods INDO/S (intermediate neglect of differential overlap with a spectroscopic parameterization) and MEP (molecular electrostatic potential). The ratio of radiative and non-radiative deactivation channels of the electronic excitation energy is established. The rate constants of photop...

  20. Moessbauer spectroscopic determination of chemical state of iron in bauxite

    International Nuclear Information System (INIS)

    The chemical state of iron contained in several kinds of bauxite, which are utilized as a raw material in the aluminum industry in Japan, were investigated by Moessbauer spectroscopy. The main compounds of iron were identified from the results, which showed variations of the Moessbauer absorption spectra with calcination and measuring temperature. Although the absorption intensities of the spectra differed significantly, major species identified were paramagnetic or superparamagnetic α-Fe2O3 in all of these bauxite samples. The superparamagnetic α-Fe2O3 was found mainly in the gibbsite-type bauxite, but not in the boehmite/gibbsite-type or the boehmite-type bauxite. The Moessbauer absorption spectra of red mud and its calcined products were also given. (author)

  1. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

    This paper presents an overview of chemical gas sensors, based on solid state technology, that are sensitive to environmental gases, such as O sub 2 , SO sub x , NO sub x , CO sub 2 and hydrocarbons. The paper is focussed on performance of electrochemical gas sensors that are based on zirconia as a solid electrolyte. The paper considers sensor structures and selection of electrode materials. Impact of interfaces on sensor performance is discussed. This paper also provides a brief overview of electrochemical properties of zirconia and their effect on sensor performance. Impact of auxiliary materials on sensors performance characteristics, such as sensitivity, selectivity, response time and recovery time, is also discussed. Dual gas sensors that can be applied for simultaneous monitoring of the concentration of both oxygen and other gas phase components, are briefly considered

  2. Copper precipitates in silicon: Precipitation, dissolution and chemical state

    International Nuclear Information System (INIS)

    The precipitation and dissolution of copper impurities at oxygen precipitates and stacking faults in silicon were studied using thermal budgets commensurate with standard integrated circuit processing. Additionally, in order to develop a better understanding of the dissolution process, we have obtained results on the chemical state of the copper precipitates. The goal of this work was to determine the feasibility of removing and maintaining copper impurities away from the active device region of an integrated circuit device by use of oxygen precipitates and stacking faults in the bulk of the material. Based on our results, we provide a basis for a predictive understanding of copper precipitation and dissolution in silicon and we discuss the feasibility of copper impurity control in silicon integrated circuit devices

  3. ISSUES IN STATE ECONOMIC ANALYSIS

    OpenAIRE

    Maki, Wilbur R.

    1984-01-01

    This paper focuses on state and local governments and the policy choices affecting the state's long-term economic outlook. It addresses the preparation, organization and use of decision information in the management of state and local governments as these governments are affected by, and, in turn, affect the economy of the state. Its particular focus is on data, but timely and accurate information on the state of the state's economy and its prospects for growth and development in a rapidly ch...

  4. Accumulation and chemical states of radiocesium by fungus Saccharomyces cerevisiae

    Science.gov (United States)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya; Yu, Qianqian

    2014-05-01

    After accident of Fukushima Daiichi Nuclear Power Plant, the fall-out radiocesium was deposited on the ground. Filamentous fungus is known to accumulate radiocesium in environment, even though many minerals are involved in soil. These facts suggest that fungus affect the migration behavior of radiocesium in the environment. However, accumulation mechanism of radiocesium by fungus is not understood. In the present study, accumulation and chemical states change of Cs by unicellular fungus of Saccharomyces cerevisiae have been studied to elucidate the role of microorganisms in the migration of radiocesium in the environment. Two different experimental conditions were employed; one is the accumulation experiments of radiocesium by S. cerevisiae from the agar medium containing 137Cs and a mineral of zeolite, vermiculite, smectite, mica, or illite. The other is the experiments using stable cesium to examine the chemical states change of Cs. In the former experiment, the cells were grown on membrane filter of 0.45 μm installed on the agar medium. After the grown cells were weighed, radioactivity in the cells was measured by an autoradiography technique. The mineral weight contents were changed from 0.1% to 1% of the medium. In the latter experiment, the cells were grown in the medium containing stable Cs between 1 mM and 10mM. The Cs accumulated cells were analyzed by SEM-EDS and EXAFS. The adsorption experiments of cesium by the cells under resting condition were also conducted to test the effect of cells metabolic activity. Without mineral in the medium, cells of S. cerevisiae accumulated 1.5x103 Bq/g from the medium containing 137Cs of 2.6x102 Bq/g. When mineral was added in the medium, concentration of 137Cs in the cells decreased. The concentration of 137Cs in the cells from the medium containing different minerals were in the following order; smectite, illite, mica > vermiculite > zeolite. This order was nearly the same as the inverse of distribution coefficient of

  5. Chemical States of Lanthanum in Carbonized La2O3-Mo Thermionic Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    王金淑; 周美玲; 王亦曼; 张久兴; 聂祚仁; 左铁镛

    2003-01-01

    The chemical reaction between lanthanum oxide and molybdenum carbide was studied by thermodynamic calculation, thermal analysis and in-situ X-ray Photoelectron Spectroscopy. The theoretical results show that at the environment allowing for the evaporation of lanthanum, such as in high vacuum, La2O3 in the La2O3-Mo materials can be reduced to metallic lanthanum by molybdenum carbide (Mo2C). To confirm the conclusion, many analysis methods such as XRD, SPS, and TG-DTA were taken. The experimental results show that the chemical state of lanthanum changes during heating. It was proved, for the first time, that reacted metallic lanthanum appears at the surface of this kind of material at high temperature.

  6. State Clean Energy Policies Analysis (SCEPA): State Tax Incentives

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, E.; Doris, E.

    2009-10-01

    As a policy tool, state tax incentives can be structured to help states meet clean energy goals. Policymakers often use state tax incentives in concert with state and federal policies to support renewable energy deployment or reduce market barriers. This analysis used case studies of four states to assess the contributions of state tax incentives to the development of renewable energy markets. State tax incentives that are appropriately paired with complementary state and federal policies generally provide viable mechanisms to support renewable energy deployment. However, challenges to successful implementation of state tax incentives include serving project owners with limited state tax liability, assessing appropriate incentive levels, and differentiating levels of incentives for technologies with different costs. Additionally, state tax incentives may result in moderately higher federal tax burdens. These challenges notwithstanding, state tax incentives that consider certain policy design characteristics can support renewable energy markets and state clean energy goals.The scale of their impact though is directly related to the degree to which they support the renewable energy markets for targeted sectors and technologies. This report highlights important policy design considerations for policymakers using state tax incentives to meet clean energy goals.

  7. Hybrid chemical and nondestructive-analysis technique

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Hybrid chemical and nondestructive analysis technique

    International Nuclear Information System (INIS)

    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

  9. Revolutionizing the United States Army's chemical defense through the acquisition of software and software-intensive systems

    OpenAIRE

    Vogelhut, Jonas.

    1999-01-01

    This thesis presents an analysis of how the United States Army can revolutionize the passage of critical chemical defense information on the battlefield. The current process for passage of this critical information is heavily dependent on short-range and stand-alone chemical detection systems, transmitted over secure radio vertically throughout the chain of command. These factors result in inaccurate, time-lagged information reaching command decision- makers, increasing the risk of contaminat...

  10. EDXRF for non-destructive chemical analysis

    International Nuclear Information System (INIS)

    One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive X-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyse a very wide concentration range, fast analysis with no sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels and also precious metals analysis. (Author)

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

    International Nuclear Information System (INIS)

    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

  12. Chemical Diversity, Origin, and Analysis of Phycotoxins.

    Science.gov (United States)

    Rasmussen, Silas Anselm; Andersen, Aaron John Christian; Andersen, Nikolaj Gedsted; Nielsen, Kristian Fog; Hansen, Per Juel; Larsen, Thomas Ostenfeld

    2016-03-25

    Microalgae, particularly those from the lineage Dinoflagellata, are very well-known for their ability to produce phycotoxins that may accumulate in the marine food chain and eventually cause poisoning in humans. This includes toxins accumulating in shellfish, such as saxitoxin, okadaic acid, 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 that are toxic to fish, the so-called ichthyotoxins. Despite numerous reports of algal blooms causing massive fish kills worldwide, only a few types of compounds, such as the karlotoxins, have been proven to be true ichthyotoxins. This review will highlight marine microalgae as the source of some of the most complex natural compounds known to mankind, with chemical structures that show no resemblance to what has been characterized from plants, fungi, or bacteria. In addition, it will summarize algal species known to be related to fish-killing blooms, but from which ichthyotoxins are yet to be characterized. PMID:26901085

  13. State-Space Formulation for Circuit Analysis

    Science.gov (United States)

    Martinez-Marin, T.

    2010-01-01

    This paper presents a new state-space approach for temporal analysis of electrical circuits. The method systematically obtains the state-space formulation of nondegenerate linear networks without using concepts of topology. It employs nodal/mesh systematic analysis to reduce the number of undesired variables. This approach helps students to…

  14. Chemical equilibrium analysis of dry hydrogen combustion

    International Nuclear Information System (INIS)

    The present work is based on a thermo-chemical equilibrium model for studying the effect of combustion of hydrogen during postulated accident scenarios in nuclear reactor containments. This model is based on the method of element potentials which seeks to minimize the free energy of the system. The condition on internal energy balance is imposed as a constraint during the minimization process. Another simplified model purely based on the internal energy balance has also been implemented to investigate the isolated impact of free energy and the conditions under which it becomes dominant. The two models have been used to extract final pressures for a wide range of initial conditions and mixture compositions that are typically found during accident scenarios. In the absence of hydrogen combustion experimental data, such models will become important for laying down a first estimate on the possible outcomes. (author)

  15. 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. PMID:23552653

  16. CERENA: ChEmical REaction Network Analyzer—A Toolbox for the Simulation and Analysis of Stochastic Chemical Kinetics

    Science.gov (United States)

    Kazeroonian, Atefeh; Fröhlich, Fabian; Raue, Andreas; Theis, Fabian J.; Hasenauer, Jan

    2016-01-01

    Gene expression, signal transduction and many other cellular processes are subject to stochastic fluctuations. The analysis of these stochastic chemical kinetics is important for understanding cell-to-cell variability and its functional implications, but it is also challenging. A multitude of exact and approximate descriptions of stochastic chemical kinetics have been developed, however, tools to automatically generate the descriptions and compare their accuracy and computational efficiency are missing. In this manuscript we introduced CERENA, a toolbox for the analysis of stochastic chemical kinetics using Approximations of the Chemical Master Equation solution statistics. CERENA implements stochastic simulation algorithms and the finite state projection for microscopic descriptions of processes, the system size expansion and moment equations for meso- and macroscopic descriptions, as well as the novel conditional moment equations for a hybrid description. This unique collection of descriptions in a single toolbox facilitates the selection of appropriate modeling approaches. Unlike other software packages, the implementation of CERENA is completely general and allows, e.g., for time-dependent propensities and non-mass action kinetics. By providing SBML import, symbolic model generation and simulation using MEX-files, CERENA is user-friendly and computationally efficient. The availability of forward and adjoint sensitivity analyses allows for further studies such as parameter estimation and uncertainty analysis. The MATLAB code implementing CERENA is freely available from http://cerenadevelopers.github.io/CERENA/. PMID:26807911

  17. The chemical states of tellurium produced by spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    The distribution of the chemical states of tellurium isotopes produced by 252Cf spontaneous fission, collected separately in the matrixes of NaCl, Kl, NaF, CH3COONa x 3H2O, Na2SO4 and NaNO3 crystals was investigated. Two chemical states of tellurium isotopes maintained in these matrixes are Te(IV) and Te(VI). The relationships between the distribution of the chemical states of tellurium isotopes and the produced mode of tellurium, the chemical properties of collection matrixes, the time for collecting fission fragments are studied and the possible mechanism of the interactions of the fission products and the matrixes is discussed. The results show that the distribution of chemical states of tellurium isotopes depends primarily on the chemical properties of the collection matrixes. (author) 18 refs.; 2 figs.; 10 tabs

  18. Surface functionalization of solid state ultra-high molecular weight polyethylene through chemical grafting

    Science.gov (United States)

    Sherazi, Tauqir A.; Rehman, Tayyiba; Naqvi, Syed Ali Raza; Shaikh, Ahson Jabbar; Shahzad, Sohail Anjum; Abbas, Ghazanfar; Raza, Rizwan; Waseem, Amir

    2015-12-01

    The surface of ultra-high molecular weight polyethylene (UHMWPE) powder was functionalized with styrene using chemical grafting technique. The grafting process was initiated through radical generation on base polymer matrix in the solid state by sodium thiosulfate, while peroxides formed at radical sites during this process were dissociated by ceric ammonium nitrate. Various factors were optimized and reasonably high level of monomer grafting was achieved, i.e., 15.6%. The effect of different acids as additive and divinyl benzene (DVB) as a cross-linking agent was also studied. Post-grafting sulfonation was conducted to introduce the ionic moieties to the grafted polymer. Ion-exchange capacity (IEC) was measured experimentally and is found to be 1.04 meq g-1, which is in close agreement with the theoretical IEC values. The chemical structure of grafted and functionalized polymer was characterized by attenuated total reflection infrared spectroscopy (ATR-FTIR) and thermal properties were investigated by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis depicts that the presence of radicals on the polymer chain accelerates the thermal decomposition process. The results signify that the chemical grafting is an effective tool for substantial surface modification and subsequent functionalization of polyethylene.

  19. Determination of chemical states of sulphur 35 obtained from the 35Cl (n, p)35S

    International Nuclear Information System (INIS)

    The chemical states of sulphur-35 obtained from the 35Cl(n,p)35S reaction by the irradiation of potassium chloride without any previous treatment and with previous heating under vacuum, were determined. The influence of irradiation time and temperature after irradiation was examined. Paper electrophoresis technique was employed for the determination of the chemical states. (Author)

  20. Combinatorial nano chemical technology and solid state physics. Innovation in oxide and organic electronics research

    International Nuclear Information System (INIS)

    Solid state physics is based on well-defined materials made by the sophisticated chemical synthesis. Emerging combinatorial chemical technology is coupled with nano-technology to facilitate breakthroughs in solid state physics by speeding up the screening of materials. Examples are presented from oxide crystals and organic molecules for electronics. (author)

  1. Chemical aspects of nuclear methods of analysis

    International Nuclear Information System (INIS)

    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

  2. Arrays in biological and chemical analysis

    DEFF Research Database (Denmark)

    Christensen, Claus Bo Vöge

    2002-01-01

    Recently a dramatic change has happened for biological and biochemical analysis. Originally developed as an academic massive parallel screening tool, industry has caught the idea as well of performing all kinds of assays in the new format of microarrays. From food manufacturers over water supply...

  3. Isotopes in chemical analysis for water management

    International Nuclear Information System (INIS)

    Surface or underground water circulations and interactions are more and more often studied with the help of geochemistry and more particularly by using isotopic tracers. These isotopic tracer techniques allow, in particular, to define for each system under study, the natural or anthropic origin of the chemical elements, their behaviour, their transport in the different compartments, the circulation schemes of deep fluids and their interaction with the surrounding rocks. This article presents: 1 - the isotopes: definition, measurements and uses (stable and instable isotopes, measurement means, some examples: stable isotopes of the water molecule, boron isotopes, sulfur and oxygen isotopes of sulfates, strontium isotopes, nitrogen isotopes of nitrates); 2 - isotopes and water cycle: atmospheric tracing (rainfall signal at the drainage basin scale and at the country scale, aerosols characterization in urban areas), management of alluvial aquifers, underground waters and origin of nitrogenous contaminations, underground and surface waters in the context of aquifer floods: the case of the Somme basin, underground waters at the basin scale: heterogeneities, interactions and management processes (stable isotopes of the water molecule, S and O isotopes of dissolved sulfates, strontium isotopes); 3 - conclusion. (J.S.)

  4. Domains of States of Chemical Systems: Le Chatelier Response, Structure of the Domains and Evolution

    OpenAIRE

    Zilbergleyt, B.

    2005-01-01

    The paper investigates influence of the Le Chatelier response on the chemical system behavior under stress, the shape of its domains of states in terms of static and dynamic bifurcation diagrams, and the system proneness to evolution. The usage of maps in thermodynamics of chemical systems is discussed. Thermodynamics of chemical triggers, designed in similarity with laser, is described. Results of this work are important in context of new model of chemical equilibrium.

  5. State and tendencies of chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Papers published in 1976 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

  6. State and tendencies of chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Papers published in 1979 and 1980 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in in-vivo and model systems, the biochemical, pharmacological and toxic effects, and modes of action of radioprotective agents are described and the trends in this field of research estimated. (author)

  7. State and tendencies of chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Papers published in 1975 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

  8. Some Chemical and Electronic Considerations of Solid State Semiconductor Crystals.

    Science.gov (United States)

    Hinitz, Herman J.

    1986-01-01

    Describes the trend toward the use of electronic instrumentation to monitor and measure various parameters in chemical reactions. Stresses that a knowledge of the operational relationships involved in such instruments is essential for students beginning in science. Discusses electrostatic charges, semiconductor crystals, electronic conductors,…

  9. State and tendencies of chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Papers published in 1978 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in in-vivo and model systems, the biochemical, pharmacological and toxic effects, and modes of action of radioprotective agents are described and the trends in this field of research appreciated. (author)

  10. State and tendencies of chemical protection against ionizing radiation

    International Nuclear Information System (INIS)

    Papers published in 1974 in the field of chemical protection against ionizing radiation are reviewed. Protection studies in vitro and in vivo, the biochemical, pharmacological and toxic effects, the mechanisms of protection of radioprotective agents and the trends in this field of research are described. (author)

  11. Controlling the accuracy of chemical analysis

    International Nuclear Information System (INIS)

    Most of the IAEA reference materials are certified in intercomparisons by calculation of the overall mean of reported laboratory mean values. IAEA certification is provided at ''A level'' (satisfactory, or high degree of confidence), or at ''B level'' (acceptable, or reasonable degree of confidence) sampling , storage and preliminary processing, use of reliable analytical methods, internal and external control of accuracy and reliability result in excellent certified reference materials for inorganic, geologic, environmental, biological and other quantitative analysis by means of conventional and nuclear methods. 34 refs, 4 figs, 3 tabs

  12. Chemical form analysis method of particulate nickel compounds

    International Nuclear Information System (INIS)

    Chemical form of nickel is metallic nickel, nickel oxide and nickel ferrite in the PWR primary chemistry condition. The distribution of chemical form depends on Ni/Fe ratio and chemistry condition, especially dissolved hydrogen concentration. Nickel is parent element of Co-58 and the chemical form is important for Co-58 generation. A method of chemical form analysis of nickel has been developed. This method uses the difference in dissolution characteristics of nickel compounds. Metallic nickel and others are separated by nitric acid, and others are divided to nickel oxide and nickel ferrite by oxalic acid. Some cruds in the primary coolant of a PWR were analyzed by using this method. The method is not complex and available at chemical laboratory in a nuclear power plant. (author)

  13. Attainable entanglement of unitary transformed thermal states in liquid-state nuclear magnetic resonance with the chemical shift

    CERN Document Server

    Ota, Y; Ohba, I; Yoshida, N; Mikami, Shuji; Ohba, Ichiro; Ota, Yukihiro; Yoshida, Noriyuki

    2006-01-01

    Recently, Yu, Brown, and Chuang [Phys. Rev. A {\\bf 71}, 032341 (2005)] investigated the entanglement attainable from unitary transformed thermal states in liquid-state nuclear magnetic resonance (NMR). Their research gave an insight into the role of the entanglement in a liquid-state NMR quantum computer. Moreover, they attempted to reveal the role of mixed-state entanglement in quantum computing. However, they assumed that the Zeeman energy of each nuclear spin which corresponds to a qubit takes a common value for all; there is no chemical shift. In this paper, we research a model with the chemical shifts and analytically derive the physical parameter region where unitary transformed thermal states are entangled, by the positive partial transposition (PPT) criterion with respect to any bipartition. We examine the effect of the chemical shifts on the boundary between the separability and the nonseparability, and find it is negligible.

  14. State Space Truncation with Quantified Errors for Accurate Solutions to Discrete Chemical Master Equation.

    Science.gov (United States)

    Cao, Youfang; Terebus, Anna; Liang, Jie

    2016-04-01

    The discrete chemical master equation (dCME) provides a general framework for studying stochasticity in mesoscopic reaction networks. Since its direct solution rapidly becomes intractable due to the increasing size of the state space, truncation of the state space is necessary for solving most dCMEs. It is therefore important to assess the consequences of state space truncations so errors can be quantified and minimized. Here we describe a novel method for state space truncation. By partitioning a reaction network into multiple molecular equivalence groups (MEGs), we truncate the state space by limiting the total molecular copy numbers in each MEG. We further describe a theoretical framework for analysis of the truncation error in the steady-state probability landscape using reflecting boundaries. By aggregating the state space based on the usage of a MEG and constructing an aggregated Markov process, we show that the truncation error of a MEG can be asymptotically bounded by the probability of states on the reflecting boundary of the MEG. Furthermore, truncating states of an arbitrary MEG will not undermine the estimated error of truncating any other MEGs. We then provide an overall error estimate for networks with multiple MEGs. To rapidly determine the appropriate size of an arbitrary MEG, we also introduce an a priori method to estimate the upper bound of its truncation error. This a priori estimate can be rapidly computed from reaction rates of the network, without the need of costly trial solutions of the dCME. As examples, we show results of applying our methods to the four stochastic networks of (1) the birth and death model, (2) the single gene expression model, (3) the genetic toggle switch model, and (4) the phage lambda bistable epigenetic switch model. We demonstrate how truncation errors and steady-state probability landscapes can be computed using different sizes of the MEG(s) and how the results validate our theories. Overall, the novel state space

  15. 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. PMID:14762640

  16. Analysis of Joint Ventures Financial State

    Directory of Open Access Journals (Sweden)

    Alla V. Dmitrenko

    2013-01-01

    Full Text Available The article describes the basic techniques for the analysis of businesses financial state and methods that were adapted for the joint ventures activities, analyses joint venture financial state, makes conclusions and submits reasonable proposals for improvement of its future activities

  17. Appendix C. Collection of Samples for Chemical Agent Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Koester, C; Thompson, C; Doerr, T; Scripsick, R

    2005-09-23

    This chapter describes procedures for the collection and analysis of samples of various matrices for the purpose of determining the presence of chemical agents in a civilian setting. This appendix is intended to provide the reader with sufficient information to make informed decisions about the sampling and analysis process and to suggest analytical strategies that might be implemented by the scientists performing sampling and analysis. This appendix is not intended to be used as a standard operating procedure to provide detailed instructions as to how trained scientists should handle samples. Chemical agents can be classified by their physical and chemical properties. Table 1 lists the chemical agents considered by this report. In selecting sampling and analysis methods, we have considered procedures proposed by the Organization for Prohibition of Chemical Weapons (OPCW), the U. S. Environmental Protection Agency (EPA), and peer-reviewed scientific literature. EPA analytical methods are good resources describing issues of quality assurance with respect to chain-of-custody, sample handling, and quality control requirements.

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

    International Nuclear Information System (INIS)

    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

  19. Chemical reaction rates and non-equilibrium pressure of reacting gas mixtures in the state-to-state approach

    International Nuclear Information System (INIS)

    Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N2 flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure

  20. On the graph and systems analysis of reversible chemical reaction networks with mass action kinetics

    OpenAIRE

    Rao, Shodhan; Jayawardhana, Bayu; der Schaft, Arjan van

    2012-01-01

    Motivated by the recent progresses on the interplay between the graph theory and systems theory, we revisit the analysis of reversible chemical reaction networks described by mass action kinetics by reformulating it using the graph knowledge of the underlying networks. Based on this formulation, we can characterize the space of equilibrium points and provide simple dynamical analysis on the state space modulo the space of equilibrium points.

  1. The equation of state of QCD at finite chemical potential

    CERN Document Server

    Gupta, Sourendu; Majumdar, Pushan

    2014-01-01

    We obtain the baryon number density, n, and the excess contribution to the pressure, Delta P, at finite chemical potential, mu_B, and temperature, T, by resumming the Taylor series expansion in a lattice computation with lattice spacing of 1/(4T) and two flavours of quarks at three different quark masses. The method proceeds by giving a critical mu_B and limits on the critical exponent, and permits reliable estimations of the errors in resummed quantities. We find that n and Delta P are insensitive to the quark mass. We also report the bulk isothermal compressibility, kappa, over a range of T and mu_B.

  2. Terahertz Chemical Analysis of Exhaled Human Breath - Broad Essay of Chemicals

    Science.gov (United States)

    Branco, Daniela R.; Fosnight, Alyssa M.; Thomas, Jessica R.; Medvedev, Ivan R.

    2013-06-01

    Approximately 3000 chemicals are thought to be present in human breath. Of these chemicals, many are considered typical of exhaled air. Yet, others can allude to different disease pathologies. The detection of chemicals in breath could have many practical purposes in medicine and provide a noninvasive means of diagnostics. We have previously reported on detection of ethanol, methanol, and acetone in exhaled human breath using a novel sub-millimeter/THz spectroscopic approach. This paper reports on our most recent study. A tentative list has been made of approximately 20 chemicals previously found in breath using other methods. Though many of these chemicals are only expressed in samples from donors with certain pathologies, at the time of this submission we are able to detect and quantitatively measure acetaldehyde and dimethyl sulfide in the breath of several healthy donors. Additional tentatively identified chemicals have been seen using this approach. This presentation will explain our experimental procedures and present our most recent results in THz breath analysis. Prospects, challenges and future plans will be outlined and discussed.

  3. Open chemical reaction networks, steady-state loads and Braess-like paradox

    CERN Document Server

    Banerjee, Kinshuk

    2014-01-01

    Open chemical reaction systems involve matter-exchange with the surroundings. As a result, species can accumulate inside a system during the course of the reaction. We study the role of network topology in governing the concentration build-up inside a fixed reaction volume at steady state, particularly focusing on the effect of additional paths. The problem is akin to that in traffic networks where an extra route, surprisingly, can increase the overall travel time. This is known as the Braess' paradox. Here, we report chemical analogues of such a paradox in suitably chosen reaction networks, where extra reaction step(s) can inflate the total concentration, denoted as `load', at steady state. It is shown that, such counter-intuitive behavior emerges in a qualitatively similar pattern in networks of varying complexities. We then explore how such extra routes affect the load in a biochemical scheme of uric acid degradation. From a thorough analysis of this network, we propose a functional role of some decomposit...

  4. Synthesis of high surface area nanometer magnesia by solid-state chemical reaction

    Institute of Scientific and Technical Information of China (English)

    GUAN Hongbo; WANG Pei; ZHAO Biying; ZHU Yuexiang; XIE Youchang

    2007-01-01

    Nanometer MgO samples with high surface area,small crystal size and mesoporous texture were synthesized tion process accelerated the sintering of MgO,and MgO with calcining its precursor in flowing dry nitrogen at 520℃ for 4 h.The samples were characterized by X-ray diffraction,N2 adsorption,transmission electron microscopy,thermogravimetry,and differential thermal analysis.The as-prepared MgO was composed of nanocrystals with a size of about 4-5 nm and formed a wormhole-like porous structure.The MgO also had good thermal stability,and its surface areas remained at 357 and 153 m2.g-1 after calcination at 600 and 800℃ for 2 h,respectively.Compared with the MgO sample prepared by the precipitation method,MgO prepared by solid-state chemical reaction has uniform pore size distribution,surface area,and crystal size.The solid-state chemical method has the advantages of low cost,low pollution,and high yield,therefore it appears to be a promising method in the industrial manufacture of nanometer MgO.

  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. Gradient Bundle Analysis: A Full Topological Approach to Chemical Bonding

    CERN Document Server

    Morgenstern, Amanda

    2016-01-01

    The "chemical bond" is a central concept in molecular sciences, but there is no consensus as to what a bond actually is. Therefore, a variety of bonding models have been developed, each defining the structure of molecules in a different manner with the goal of explaining and predicting chemical properties. This thesis describes the initial development of gradient bundle analysis (GBA), a chemical bonding model that creates a high resolution picture of chemical interactions within the charge density framework. GBA is based on concepts from the quantum theory of atoms in molecules (QTAIM), but uses a more complete picture of the topology and geometry of the electron charge density to understand and predict bonding interactions. Gradient bundles are defined as volumes bounded by zero-flux surfaces (ZFSs) in the gradient of the charge density with well-defined energies. The structure of gradient bundles provides an avenue for detecting the locations of valence electrons, which correspond to reactive regions in a ...

  7. Surface chemical composition analysis of heat-treated bamboo

    Science.gov (United States)

    Meng, Fan-dan; Yu, Yang-lun; Zhang, Ya-mei; Yu, Wen-ji; Gao, Jian-min

    2016-05-01

    In this study, the effect of heat treatment on the chemical composition of bamboo slivers was studied. The chemical properties of the samples were examined by chemical analysis. Results showed a decrease in the contents of holocellulose and α-cellulose, as well as an increase in the contents of lignin and extractives. Changes in the chemical structure of bamboo components were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR spectroscopy results indicated that hemicellulose contents decrease, whereas lignin contents increase after heat treatment. Ester formation linked to lignin decreased the hygroscopicity of the bamboo samples and consequently improved their dimensional stability and durability. XPS spectroscopy results showed that hemicelluloses and celluloses are relatively more sensitive to the heating process than lignin. As a consequence, hemicellulose and cellulose contents decreased, whereas lignin contents increased during heat treatment. The results obtained in this study provide useful information for the future utilization of heat-treated bamboo.

  8. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge

    Directory of Open Access Journals (Sweden)

    Joana Martins

    2015-11-01

    Full Text Available Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential.

  9. Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge.

    Science.gov (United States)

    Martins, Joana; Vasconcelos, Vitor

    2015-11-01

    Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential. PMID:26580631

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    Chemical characterization of solid waste is a demanding task due to the heterogeneity of the waste. This article describes how 45 material fractions hand-sorted from Danish household waste were subsampled and prepared for chemical analysis of 61 substances. All material fractions were subject to...... repeated particle-size reduction, mixing, and mass reduction until a sufficiently small but representative sample was obtained for digestion prior to chemical analysis. The waste-fraction samples were digested according to their properties for maximum recognition of all the studied substances. By combining...... 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...

  11. The Impact of Flow Injection on Modern Chemical Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA-publications in...

  12. 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 - Forest ry

  13. 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...

  14. Research Institute for Physical Chemical Problems of the Belarusian State University

    OpenAIRE

    2015-01-01

    Edition contains information about the history of Research Institute for Physical Chemical Problems of the Belarusian State University, contact data and institute`s structure. The main developments of the institute are described also.Edition contains information about the history of Research Institute for Physical Chemical Problems of the Belarusian State University, contact data and institute`s structure. The main developments of the institute are described also.

  15. 3D thermo-chemical-mechanical analysis of the pultrusion process

    DEFF Research Database (Denmark)

    Baran, Ismet; Hattel, Jesper Henri; Tutum, Cem C.

    2013-01-01

    In the present study, a 3D Eulerian thermo-chemical analysis is sequentially coupled with a 3D Lagrangian quasi static mechanical analysis of the pultrusion process. The temperature and degree of cure profiles at the steady state are first calculated in the thermo-chemical analysis. In the...... mechanical analysis, the developments of the process induced stresses and distortions during the process are predicted using the already obtained temperature and degree of cure profiles together with the glass transition temperature. The predictions of the transverse transient stresses and distortions are...... found to be similar as compared to the available data in the literature. Using the proposed 3D mechanical analysis, different mechanical behaviour is obtained for the longitudinal stress development as distinct from the stress development in the transverse directions. Even though the matrix material is...

  16. Present state of the combined treatment with radiation and chemicals

    International Nuclear Information System (INIS)

    Of malignancies in which the results have been markedly improved by combined treatment with radiation and chemicals for the past decade, non-Hodgkin's lymphoma localized in head and neck and intra-oral carcinoma are presented. In the management of non-Hodgkin's lymphoma, the authors stressed the following: 1) Rappaport's classification has been a help to evaluate the prognosis; 2) lymphoma of the Waldeyer's ring should not be included in nodal lymphoma, and also it should be separated from extranodal lymphoma as well, because of different prognosis; 3) It seems that some kinds of chemotherapy would have a role in improving the results of radiotherapy in the management of radiotherapy, even in localized cases. In some types of intra-oral carcinomas, bleomycin was found to be useful in the combined treatment with radiation as follows: 1) A minimum required dose for local control of intra-oral carcinomas could be a combination of 30Gy in 3 weeks and 100mg bleomycin during the same period. 2) Although the end results of patients with carcinoma of tongue or floor of mouth have not been improved by this approach, there was marked improvement in patients with carcinoma of the lower gum. 3) For the treatment, the side effect as limiting factor was mucositis, and none of the cases of the series developed pulmonary complication. In the cases controlled by initial combined treatment, no one developed troubles of the mandible, in the follow-up study for the past 10 years. (author)

  17. Coherent states, pseudodifferential analysis and arithmetic

    International Nuclear Information System (INIS)

    Basic questions regarding families of coherent states include describing some constructions of such and the way they can be applied to operator theory or partial differential equations. In both questions, pseudodifferential analysis is important. Recent developments indicate that they can contribute to methods in arithmetic, especially modular form theory. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

  18. Chemical climatology of the southeastern United States, 1999–2013

    Directory of Open Access Journals (Sweden)

    G. M. Hidy

    2014-06-01

    Full Text Available A series of experiments (the Southern Oxidant and Aerosol Study-SOAS took place in central Alabama in June–July 2013 as part of the broader Southern Atmosphere Study (SAS. These projects were aimed at studying oxidant photochemistry and formation and impacts of aerosols at a detailed process level in a location where high biogenic organic vapor emissions interact with anthropogenic emissions, and the atmospheric chemistry occurs in a subtropical climate in North America. The majority of the ground-based experiments were located at the Southeastern Aerosol Research and Characterization (SEARCH Centreville (CTR site near Brent, Alabama, where extensive, unique aerometric measurements of meteorology, trace gases and particles have been made from the early 1990s through 2013. The SEARCH network data permits a characterization of temporal and spatial context of the SOAS findings. The long-term measurements show that the SOAS experiments took place during the second wettest and coolest year in the 2000–2013 period, with lower than average solar radiation. The pollution levels at CTR and other SEARCH sites were the lowest since full measurements began in 1999. This dataset provides a perspective for the SOAS program in terms of long-term average chemistry (chemical climatology and short-term comparisons of summer average spatial variability across the Southeast at high temporal (hourly resolution. Changes in anthropogenic gas and particle emissions between 1999 and 2013, account for the decline in pollutant concentrations at the monitoring sites in the region. The long-term and short-term data provide an opportunity to contrast SOAS results with temporally and spatially variable conditions in support for the development of tests for the robustness of SOAS findings.

  19. Trends in Indian Patent Filing in Chemical Sciences: An Analysis

    Directory of Open Access Journals (Sweden)

    N.B. Dahibhate,

    2012-05-01

    Full Text Available The paper analyses the trends in Indian patents filed in the area of chemical sciences during 1995 to2008. It highlights the importance of patent literature in scientific developments and global trends in patentfilings. A result of Indian patent filing analysis indicated that filing in India is increasing in the past few yearsand many public and private organisations are filing patents in India and in other countries for protecting theinventions. Among India patent filing activities, chemical and pharmaceutical sciences are the prominent areas.Individual inventors and assignees from private and public organisations are filing patents, but in India, Councilof Scientific & Industrial Research (CSIR is leading patent filer.

  20. An Extended Algorithm of Flexibility Analysis in Chemical Engineering Processes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibility region of the process system operation. The hyperrectangular flexibility region determined by the extended algorithm is larger than that calculated by the previous algorithms. The limitation of the proposed algorithm due to imperfect convexity and its corresponding verification measure are also discussed. Both numerical and actual chemical process examples are presented to demonstrate the effectiveness of the new algorithm.

  1. Chemical Cytometry: Fluorescence-Based Single-Cell Analysis

    Science.gov (United States)

    Cohen, Daniella; Dickerson, Jane A.; Whitmore, Colin D.; Turner, Emily H.; Palcic, Monica M.; Hindsgaul, Ole; Dovichi, Norman J.

    2008-07-01

    Cytometry deals with the analysis of the composition of single cells. Flow and image cytometry employ antibody-based stains to characterize a handful of components in single cells. Chemical cytometry, in contrast, employs a suite of powerful analytical tools to characterize a large number of components. Tools have been developed to characterize nucleic acids, proteins, and metabolites in single cells. Whereas nucleic acid analysis employs powerful polymerase chain reaction-based amplification techniques, protein and metabolite analysis tends to employ capillary electrophoresis separation and ultrasensitive laser-induced fluorescence detection. It is now possible to detect yoctomole amounts of many analytes in single cells.

  2. Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

    Science.gov (United States)

    Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

    2015-03-01

    Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data. PMID:25647718

  3. Chemical reactions of ultracold alkali dimers in the lowest-energy $^3\\Sigma$ state

    CERN Document Server

    Tomza, Michał; Moszynski, Robert; Krems, Roman V

    2013-01-01

    We show that the interaction of polar alkali dimers in the quintet spin state leads to the formation of a deeply bound reaction complex. The reaction complex can decompose adiabatically into homonuclear alkali dimers (for all molecules except KRb) and into alkali trimers (for all molecules). We show that there are no barriers for these chemical reactions. This means that all alkali dimers in the $a^3\\Sigma^+$ state are chemically unstable at ultracold temperature, and the use of an optical lattice to segregate the molecules and suppress losses may be necessary. In addition, we calculate the minimum energy path for the chemical reactions of alkali hydrides. We find that the reaction of two molecules is accelerated by a strong attraction between the alkali atoms, leading to a barrierless process that produces hydrogen atoms with large kinetic energy. We discuss the unique features of the chemical reactions of ultracold alkali dimers in the $a^3\\Sigma^+$ electronic state.

  4. Moessbauer study of the chemical state of gold in gold ores

    International Nuclear Information System (INIS)

    Information on the chemical state of gold in gold ores has been obtained by 197Au Moessbauer spectroscopy in cases where the state of this element cannot be determined by such standard methods as optical or electron microscopy. Ore concentrates consisting mainly of pyrite or arsenopyrite and roasted ore and matte samples were studied. The results yielded directly the respective amounts of metallic and chemically bound gold. Unless the gold is metallic, its chemical state in the ores turns out to be different from that in the minerals studied so far as reference materials. The chemical processes taking place during various treatments of the ores, such as roasting or leaching, can also be followed by Moessbauer spectroscopy. It is hoped that Moessbauer spectroscopy will eventually facilitate the development of more efficient methods of gold extraction

  5. Chemical analysis of thin films at Sandia National Laboratories

    International Nuclear Information System (INIS)

    The characterization of thin films produced by chemical and physical vapor deposition requires special analytical techniques. When the average compositions of the films are required, dissolution of the thin films and measurement of the concentrations of the solubilized species is the appropriate analytical approach. In this report techniques for the wet chemical analysis of thin films of Si:Al, P2O5:SiO2, B2O3:SiO2, TiB/sub x/ and TaB/sub x/ are described. The analyses are complicated by the small total quantities of these analytes present in the films, the refractory characters of these analytes, and the possibility of interferences from the substrates on which the films are deposited. Etching conditions are described which dissolve the thin films without introducing interferences from the substrates. A chemical amplification technique and inductively coupled plasma atomic emission spectrometry are shown to provide the sensitivity required to measure the small total quantities (micrograms to milligrams) of analytes present. Also the chemical analysis data has been used to calibrate normal infrared absorption spectroscopy to give fast estimates of the phosphorus and/or boron dopant levels in thin SiO2 films

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

    International Nuclear Information System (INIS)

    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

  7. Shock-induced solid-state chemical reactivity studies using time-resolved radiation pyrometry

    International Nuclear Information System (INIS)

    Time-resolved radiation pyrometry has been used to study materials which undergo solid-state chemical reactions due to shock loading. Shock-induced chemical reactivity in solids is fundamentally different than that in high explosives and other energetic materials because, if no volatiles are present, the reaction products end up in the condensed, rather than the vapor, state. Bulk property changes accompanying the solid-state reactions may therefore be too small to be observable with wave profile or shock-velocity measurements. However, some solid-state reactions, such as that between metallic nickel and aluminum, are exothermic enough to give rise to a measurable increase in temperature, so pyrometry can be used to detect the reactions. Unfortunately, these measurements are complicated by the large temperature increases generated by other sources. Possible mechanisms for generation of these high temperatures, and their effect on the chemical reaction, are suggested

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

    OpenAIRE

    Marius BREBENEL

    2014-01-01

    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 ...

  9. Development of microfluidic devices for chemical analysis and fluid handling

    OpenAIRE

    Egidi, Giovanni; De Rooij, Nicolas F

    2004-01-01

    Miniaturization of chemical analysis and synthesis systems improve throughput, performance and accessibility, and lead to significantly reduced costs. In this work are described several components that find place in the process of miniaturization. This work is developed in the frame of the project CREAM (Cartridges with molecularly imprinted Recognition Elements for Antibiotic residues Monitoring in Milk). Antibiotics are widely used to treat cows' diseases, and traces can be found in milk so...

  10. Device for high spatial resolution chemical analysis of a sample and method of high spatial resolution chemical analysis

    Science.gov (United States)

    Van Berkel, Gary J.

    2015-10-06

    A system and method for analyzing a chemical composition of a specimen are described. The system can include at least one pin; a sampling device configured to contact a liquid with a specimen on the at least one pin to form a testing solution; and a stepper mechanism configured to move the at least one pin and the sampling device relative to one another. The system can also include an analytical instrument for determining a chemical composition of the specimen from the testing solution. In particular, the systems and methods described herein enable chemical analysis of specimens, such as tissue, to be evaluated in a manner that the spatial-resolution is limited by the size of the pins used to obtain tissue samples, not the size of the sampling device used to solubilize the samples coupled to the pins.

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

    International Nuclear Information System (INIS)

    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)

  12. Analysis of the stochastic excitability in the flow chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bashkirtseva, Irina [Ural Federal University, Lenina, 51, Ekaterinburg, 620000 (Russian Federation)

    2015-11-30

    A dynamic model of the thermochemical process in the flow reactor is considered. We study an influence of the random disturbances on the stationary regime of this model. A phenomenon of noise-induced excitability is demonstrated. For the analysis of this phenomenon, a constructive technique based on the stochastic sensitivity functions and confidence domains is applied. It is shown how elaborated technique can be used for the probabilistic analysis of the generation of mixed-mode stochastic oscillations in the flow chemical reactor.

  13. Methods of remote surface chemical analysis for asteroid missions

    International Nuclear Information System (INIS)

    Different remote sensing methods are discussed which can be applied to investigate the chemical composition of minor bodies of the Solar System. The secondary-ion method, remote laser mass-analysis and electron beam induced X-ray emission analysis are treated in detail. Relative advantages of these techniques are analyzed. The physical limitation of the methods: effects of solar magnetic field and solar wind on the secondary-ion and laser methods and the effect of electrostatic potential of the space apparatus on the ion and electron beam methods are described. First laboratory results of remote laser method are given. (D.Gy.)

  14. Electrochemical approaches for chemical and biological analysis on Mars

    Science.gov (United States)

    Kounaves, Samuel P.

    2003-01-01

    Obtaining in situ chemical data from planetary bodies such as Mars or Europa can present significant challenges. The one analytical technique that has many of the requisite characteristics to meet such a challenge is electroanalysis. Described here are three electroanalytical devices designed for in situ geochemical and biological analysis on Mars. The Mars Environmental Compatibility Assessment (MECA) was built and flight qualified for the now cancelled NASA Mars 2001 Lander. Part of MECA consisted of four "cells" containing arrays of electrochemical based sensors for measuring the ionic species in soil samples. A next-generation MECA, the Robotic Chemical Analysis Laboratory (RCAL), uses a carousel-type system to allow for greater customization of analytical procedures. A second instrument, proposed as part of the 2007 CryoScout mission, consists of a flow-through inorganic chemical analyzer (MICA). CryoScout is a torpedo-like device designed for subsurface investigation of the stratigraphic climate record embedded in Mars' north polar cap. As the CryoScout melts its way through the ice cap, MICA will collect and analyze the meltwater for a variety of inorganics and chemical parameters. By analyzing the chemistry locked in the layers of dust, salt, and ice, geologists will be able to determine the recent history of climate, water, and atmosphere on Mars and link it to the past. Finally, electroanalysis shows its abilities in the detection of possible microorganism on Mars or elsewhere in the solar system. To identify an unknown microorganism, one that may not even use Earth-type biochemistry, requires a detection scheme which makes minimal assumptions and looks for the most general features. Recent work has demonstrated that the use of an array of electrochemical sensors which monitors the changes in a solution via electrical conductivity, pH, and ion selective electrodes, can be used to detect minute chemical perturbations caused by the growth of bacteria and

  15. Ab initio studies of equations of state and chemical reactions of reactive structural materials

    Science.gov (United States)

    Zaharieva, Roussislava

    The motivations for the research issues addressed in this thesis are based on the needs of the aerospace structural analysis and the design community. The specific focus is related to the characterization and shock induced chemical reactions of multi-functional structural-energetic materials that are also known as the reactive structural materials and their reaction capabilities. Usually motivation for selection of aerospace structural materials is to realize required strength characteristics and favorable strength to weight ratios. The term strength implies resistance to loads experienced during the service life of the structure, including resistance to fatigue loads, corrosion and other extreme conditions. Thus, basically the structural materials are single function materials that resist loads experienced during the service life of the structure. However, it is desirable to select materials that are capable of offering more than one basic function of strength. Very often, the second function is the capability to provide functions of sensing and actuation. In this thesis, the second function is different. The second function is the energetic characteristics. Thus, the choice of dual functions of the material are the structural characteristics and energetic characteristics. These materials are also known by other names such as the reactive material structures or dual functional structural energetic materials. Specifically the selected reactive materials include mixtures of selected metals and metal oxides that are also known as thermite mixtures, reacting intermetallic combinations and oxidizing materials. There are several techniques that are available to synthesize these structural energetic materials or reactive material structures and new synthesis techniques constitute an open research area. The focus of this thesis, however, is the characterization of chemical reactions of reactive material structures that involve two or more solids (or condensed matter). The

  16. Linear Covariance Analysis and Epoch State Estimators

    Science.gov (United States)

    Markley, F. Landis; Carpenter, J. Russell

    2014-01-01

    This paper extends in two directions the results of prior work on generalized linear covariance analysis of both batch least-squares and sequential estimators. The first is an improved treatment of process noise in the batch, or epoch state, estimator with an epoch time that may be later than some or all of the measurements in the batch. The second is to account for process noise in specifying the gains in the epoch state estimator. We establish the conditions under which the latter estimator is equivalent to the Kalman filter.

  17. Analysis of equations of state for polymers

    Directory of Open Access Journals (Sweden)

    Erlí José Padilha Júnior

    2015-06-01

    Full Text Available AbstractIn the literature there are several studies comparing the accuracy of various models in describing the PvT behavior of polymers. However, most of these studies do not provide information about the quality of the estimated parameters or the sensitivity of the prediction of thermodynamic properties to the parameters of the equations. Furthermore, there are few studies exploring the prediction of thermal expansion and compression coefficients. Based on these observations, the objective of this study is to deepen the analysis of Tait, HH (Hartmann-Haque, MCM (modified cell model and SHT (simplified hole theory equations of state in predicting the PvT behavior of polymers, for both molten and solid states. The results showed that all equations of state provide an adequate description of the PvT behavior in the molten state, with low standard deviations in the estimation of parameters, adequate sensitivity of their parameters and plausible prediction of specific volume, thermal expansion and isothermal compression coefficients. In the solid state the Tait equation exhibited similar performance to the molten state, while HH showed satisfactory results for amorphous polymers and difficulty in adjusting the PvT curve for semicrystalline polymers.

  18. Soft x-ray spectroscopy for probing electronic and chemical states of battery materials

    Science.gov (United States)

    Wanli, Yang; Ruimin, Qiao

    2016-01-01

    The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode-electrolyte interfaces, chemical reactions take place with evolving electron states. In addition to the extensive studies of material synthesis, electrochemical, structural, and mechanical properties, soft x-ray spectroscopy provides unique opportunities for revealing the critical electron states in batteries. This review discusses some of the recent soft x-ray spectroscopic results on battery binder, transition-metal based positive electrodes, and the solid-electrolyte-interphase. By virtue of soft x-ray’s sensitivity to electron states, the electronic property, the redox during electrochemical operations, and the chemical species of the interphases could be fingerprinted by soft x-ray spectroscopy. Understanding and innovating battery technologies need a multimodal approach, and soft x-ray spectroscopy is one of the incisive tools to probe the chemical and physical evolutions in batteries.

  19. Quantitative analysis of chemical elements in single cells using nuclear microprobe and nano-probe

    International Nuclear Information System (INIS)

    The study of the role of trace elements at cellular level requires the use of state-of-the-art analytical tools that could achieve enough sensitivity and spatial resolution. We developed a new methodology for the accurate quantification of chemical element distribution in single cells based on a combination of ion beam analysis techniques STIM, PIXE and RBS. The quantification procedure relies on the development of a STIM data analysis software (Paparamborde). Validity of this methodology and limits are discussed here. The method allows the quantification of trace elements (μg/g) with a 19.8 % uncertainty in cellular compartments with mass below 0.1 ng. The main limit of the method lies in the poor number of samples that can be analyzed, due to long irradiation times required and limited access to ion beam analysis facilities. This is the reason why we developed a database for cellular chemical composition capitalization (BDC4). BDC4 has been designed in order to use cellular chemical composition as a tracer for biological activities and is expected to provide in the future reference chemical compositions for any cellular type or compartment. Application of the STIM-PIXE-RBS methodology to the study of nuclear toxicology of cobalt compounds is presented here showing that STIM analysis is absolutely needed when organic mass loss appears during PIXE-RBS irradiation. (author)

  20. Tip enhanced Raman scattering: plasmonic enhancements for nanoscale chemical analysis

    Science.gov (United States)

    Schultz, Zachary D.; Marr, James M.; Wang, Hao

    2014-04-01

    Tip enhanced Raman scattering (TERS) is an emerging technique that uses a metalized scanning probe microscope tip to spatially localize electric fields that enhances Raman scattering enabling chemical imaging on nanometer dimensions. Arising from the same principles as surface enhanced Raman scattering (SERS), TERS offers unique advantages associated with controling the size, shape, and location of the enhancing nanostructure. In this article we discuss the correlations between current understanding of SERS and how this relates to TERS, as well as how TERS provides new understanding and insights. The relationship between plasmon resonances and Raman enhancements is emphasized as the key to obtaining optimal TERS results. Applications of TERS, including chemical analysis of carbon nanotubes, organic molecules, inorganic crystals, nucleic acids, proteins, cells and organisms, are used to illustrate the information that can be gained. Under ideal conditions TERS is capable of single molecule sensitivity and sub-nanometer spatial resolution. The ability to control plasmonic enhancements for chemical analysis suggests new experiments and opportunities to understand molecular composition and interactions on the nanoscale.

  1. Chemical Bond Analysis of Single Crystal Growth of Magnesium Oxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Starting from the crystallographic structure of magnesium oxide (MgO), both the chemical bond model of solids and Pauling's third rule (polyhedral sharing rule) were employed to quantitatively analyze the chemical bonding structure of constituent atoms and single crystal growth. Our analytical results show that MgO single crystals prefer to grow along the direction and the growth rate of the {100} plane is the slowest one. Therefore, the results show that the {100} plane of MgO crystals can be the ultimate morphology face, which is in a good agreement with our previous experimental results. The study indicate that the structure analysis is an effective tool to control the single-crystal growth.

  2. Microarray Technology for Major Chemical Contaminants Analysis in Food: Current Status and Prospects

    OpenAIRE

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

    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....

  3. Surface and Lightning Sources of Nitrogen Oxides over the United States: Magnitudes, Chemical Evolution, and Outflow

    Science.gov (United States)

    Hudman, Rynda C.; Jacob, Daniel J.; Turquety, Solene; Leinbensperger, E. M.; Murray, L. T.; Wu, Samuel; Gilliland, A. B.; Avery, Melody A.; Bertram, Timothy H.; Brune, W. H.; Cohen, Ronald C.; Dibb, Jack E.; Flocke, F. M.; Fried, Alan; Holloway, J.; Neuman, J. A.; Orville, R.; Perring, Anne; Ren, Xinrong; Ryerson, T. B.; Sachse, Glen W.; Singh, H. B.; Swanson, Aaron; Wooldridge, Paul J.

    2007-01-01

    We use observations from two aircraft during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of the regional sources, chemical evolution, and export of nitrogen oxides. The boundary layer NO(x) data provide top-down verification of a 50% decrease in power plant and industry NO(x) emissions over the eastern United States between 1999 and 2004. Observed 8-12 8 km NO(x) concentrations in ICARTT were 0.55 +/- 36 ppbv, much larger than in previous United States aircraft campaigns (ELCHEM, SUCCESS, SONEX). We show that regional lightning was the dominant source of this NO(x) and increased upper tropospheric ozone by 10 ppbv. Simulating the ICARTT upper tropospheric NO(x) observations with GEOS-Chem require a factor of 4 increase in the model NO(x) yield per flash (to 500 mol/flash). Observed OH concentrations were a factor of 2 lower than can be explained from current photochemical models, and if correct would imply a broader lightning influence in the upper troposphere than presently thought.An NO(y)-CO correlation analysis of the fraction f of North American NO(x) emissions vented to the free troposphere as NO(y) (sum of NO(x) and its oxidation products PAN and HNO3) s shows observed f=16+/-10 percent and modeled f=14 +/- 8 percent, consistent with previous studies. Export to the lower free troposphere is mostly HNO3 but at higher altitudes is mostly PAN. The model successfully simulates NO(y) export efficiency and speciation, supporting previous model estimates of a large U.S. contribution to tropospheric ozone through NO(x) and PAN export.

  4. LSENS, a general chemical kinetics and sensitivity analysis code for gas-phase reactions: User's guide

    Science.gov (United States)

    Radhakrishnan, Krishnan; Bittker, David A.

    1993-01-01

    A general chemical kinetics and sensitivity analysis code for complex, homogeneous, gas-phase reactions is described. The main features of the code, LSENS, are its flexibility, efficiency and convenience in treating many different chemical reaction models. The models include static system, steady, one-dimensional, inviscid flow, shock initiated reaction, and a perfectly stirred reactor. In addition, equilibrium computations can be performed for several assigned states. An implicit numerical integration method, which works efficiently for the extremes of very fast and very slow reaction, is used for solving the 'stiff' differential equation systems that arise in chemical kinetics. For static reactions, sensitivity coefficients of all dependent variables and their temporal derivatives with respect to the initial values of dependent variables and/or the rate coefficient parameters can be computed. This paper presents descriptions of the code and its usage, and includes several illustrative example problems.

  5. Chemical-state imaging of Li using scanning Auger electron microscopy

    International Nuclear Information System (INIS)

    Highlights: •Scanning Auger electron microscopy is used to image chemical states of Li. •The combined use of AES and EELS signals for the elemental mapping is powerful. •Distribution corresponding to metallic and oxidized states of Li can be imaged. -- Abstract: The demand for measurement tools to detect Li with high spatial resolution and precise chemical sensitivity is increasing with the spread of lithium-ion batteries (LIBs) for use in a wide range of applications. In this work, scanning Auger electron microscopy (SAM) is used to image chemical states of a partially oxidized Li surface on the basis of the Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS) data obtained during an oxidation process of a metal Li. We show that distribution of metallic and oxidized states of Li is clearly imaged by mapping the intensity of the corresponding AES and EELS peaks. Furthermore, a tiny difference in the extent of oxidation can be distinguished by comparing the elemental map of an AES peak with that of an EELS peak owing to the different behaviors of those signals to the chemical states of Li

  6. Catalytic activity of platinum on ruthenium electrodes with modified (electro)chemical states.

    Science.gov (United States)

    Park, Kyung-Won; Sung, Yung-Eun

    2005-07-21

    Using Pt on Ru thin-film electrodes with various (electro)chemical states designed by the sputtering method, the effect of Ru states on the catalytic activity of Pt was investigated. The chemical and electrochemical properties of Pt/Ru thin-film samples were confirmed by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. In addition, Pt nanoparticles on Ru metal or oxide for an actual fuel cell system showed an effect of Ru states on the catalytic activity of Pt in methanol electrooxidation. Finally, it was concluded that such an enhancement of methanol electrooxidation on the Pt is responsible for Ru metallic and/or oxidation sites compared to pure Pt without any Ru state. PMID:16852701

  7. 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

    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......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...... 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...

  8. 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...

  9. 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.

  10. Probabilistic Approach to Risk Analysis of Chemical Spills at Sea

    Institute of Scientific and Technical Information of China (English)

    Magda Bogalecka; Krzysztof Kolowrocki

    2006-01-01

    Risk analysis of chemical spills at sea and their consequences for sea environment are discussed. Mutual interactions between the process of the sea accident initiating events, the process of the sea environment threats, and the process of the sea environment degradation are investigated. To describe these three particular processes, the separate semi-Markov models are built. Furthermore, these models are jointed into one general model of these processes interactions.Moreover, some comments on the method for statistical identification of the considered models are proposed.

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

    Science.gov (United States)

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

    2015-08-01

    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).

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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)

  14. 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.; Gellert, R.; Achilles, C. N.; Rampe, E. B.; Bristow, T. F.; Crisp, J. A.; Sarrazin, P. C.; DesMarais, D. J.; Morookian, J. M.; Anderson, R. C.

    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.

  15. Charge-displacement analysis for excited states

    Energy Technology Data Exchange (ETDEWEB)

    Ronca, Enrico, E-mail: enrico@thch.unipg.it; Tarantelli, Francesco, E-mail: francesco.tarantelli@unipg.it [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, via Elce di Sotto 8, I-06123 Perugia (Italy); Pastore, Mariachiara, E-mail: chiara@thch.unipg.it; Belpassi, Leonardo; De Angelis, Filippo [Istituto CNR di Scienze e Tecnologie Molecolari, via Elce di Sotto 8, I-06123 Perugia (Italy); Angeli, Celestino; Cimiraglia, Renzo [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Ferrara, via Borsari 46, I-44100 Ferrara (Italy)

    2014-02-07

    We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place.

  16. Poison politics: a contentious history of consumer protection against dangerous household chemicals in the United States.

    Science.gov (United States)

    Jones, Marian Moser; Benrubi, Isidore Daniel

    2013-05-01

    The history of consumer protection against household poisons presents a key case study of the uniquely American struggle to balance public health and safety with the interests of business. By the late 19th century, package designs, warning labels, and state statutes had formed an uneven patchwork of protective mechanisms against accidental poisonings. As household chemicals proliferated in the early 20th century, physicians concerned with childhood poisonings pressured the federal government to enact legislation mandating warning labels on packaging for these substances. Manufacturers of household chemicals agreed to labeling requirements for caustic poisons but resisted broader regulation. Accidental poisonings of children continued to increase until the enactment of broad labeling and packaging legislation in the 1960s and 1970s. This history suggests that voluntary agreements between government agencies and manufacturers are inadequate to protect consumers against household poisonings and that, in the United States, protective household chemical regulation proceeds in a reactive rather than a precautionary manner. PMID:23488510

  17. Development of an Electrolyte CPA Equation of state for Applications in the Petroleum and Chemical Industries

    DEFF Research Database (Denmark)

    Maribo-Mogensen, Bjørn

    This thesis extends the Cubic Plus Association (CPA) equation of state (EoS) to handle mixtures containing ions from fully dissociated salts. The CPA EoS has during the past 18 years been applied to thermodynamic modeling of a wide range of industrially important chemicals, mainly in relation to ...

  18. Aggregate formation in a freshwater bacterial strain induced by growth state and conspecific chemical cues

    Czech Academy of Sciences Publication Activity Database

    Blom, J. F.; Horňák, Karel; Šimek, Karel; Pernthaler, J.

    2010-01-01

    Roč. 12, č. 9 (2010), s. 2486-2495. ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA206/08/0015 Institutional research plan: CEZ:AV0Z60170517 Keywords : aggregate formation * Sphingobium sp. * chemical cues * growth state Subject RIV: EE - Microbiology, Virology Impact factor: 5.537, year: 2010

  19. Chemical signature study of tupiguarani ceramic tradition from Central region of the Rio Grande do Sul state, Brazil

    International Nuclear Information System (INIS)

    In this work a model based on experimental results using chemical composition data of the pottery sherds applied to Spearmann's no parametric test, principal component analysis and discriminant analysis, was applied. The samples are soils and Tupiguarani Tradition pottery sherd from the central area of the Rio Grande do Sul State. The chemical elements , Al, Ba, Ca, Cr, Fe, K Mn, Pb, Rb, S, Si, Sr, Ti, V and Zn were determined by energy dispersive X-ray fluorescence (EDXFR) while Ce, Cu, Gd, La, Nd, Pr, Sm, Th and Y by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) techniques. Relationships among the pottery characteristics, studied sites and sherd dispersion in the several sites were proposed. Indications of chemical signature of the small pottery with function to go or not to the fire were observed. The largest dispersion is of small pottery with surface treatment no corrugated. The potteries chemical fingerprints from Ijui River, Ibicui-Vacacai Mirim River and Jacui River were verified. (author)

  20. Chemical portioning and speciation of some trace elements in soil and street dust from Khartoum state, Sudan

    International Nuclear Information System (INIS)

    In this study, surface soil and street dust samples were collected from Khartoum State, from areas exposed to industrial and traffic emission and from areas expected to be free from elemental emission to serve as control. Samples were digested using wet digestion method to determine the total concentration of Na, K, Cr, Mn, Fe, Cu, Zn and Pb using Atomic Absorption spectrophotometer (Aas), X-Ray fluorescence and flame photometer. Also samples were chemically fractionated using chemical specification method, and the solutions analyzed using Aas to determine the chemical form of the elements. Quality assurance of the data was achieved through the analysis of certified reference material. The range of the total concentration for Na, K, Mn, Fe, Cu, Zn and Pb are 400-5175, 220-4690, 0.07-315.25, 20-250, 2050.8-46000, 0.5-2305, 4.5-280, 9.5-6200 mg/kg respectively. results obtained agree with expected emission profile as inferred from the emitting source locations. Distribution of elements from emitting source locations and control samples in different chemical fractions was carried out, and the findings reinforced by enrichment factors calculations as well by the results obtained by statistical multi-variate analysis methods such as principle compared with previous literature.(Author)

  1. Inferring the unobserved chemical state of the atmosphere: idealized data assimilation experiments

    Science.gov (United States)

    Knote, C. J.; Barré, J.; Eckl, M.; Hornbrook, R. S.; Wiedinmyer, C.; Emmons, L. K.; Orlando, J. J.; Tyndall, G. S.; Arellano, A. F.

    2015-12-01

    Chemical data assimilation in numerical models of the atmosphere is a venture into uncharted territory, into a world populated by a vast zoo of chemical compounds with strongly non-linear interactions. Commonly assimilated observations exist for only a selected few of those key gas phase compounds (CO, O3, NO2), and assimilating those in models assuming linearity begs the question of: To what extent we can infer the remainder to create a new state of the atmosphere that is chemically sound and optimal? In our work we present the first systematic investigation of sensitivities that exist between chemical compounds under varying ambient conditions in order to inform scientists on the potential pitfalls when assimilating single/few chemical compounds into complex 3D chemistry transport models. In order to do this, we developed a box-modeling tool (BOXMOX) based on the Kinetic PreProcessor (KPP, http://people.cs.vt.edu/~asandu/Software/Kpp/) in which we can conduct simulations with a suite of 'mechanisms', sets of differential equations describing atmospheric photochemistry. The box modeling approach allows us to sample a large variety of atmospheric conditions (urban, rural, biogenically dominated, biomass burning plumes) to capture the range of chemical conditions that typically exist in the atmosphere. Included in our suite are 'lumped' mechanisms typically used in regional and global chemistry transport models (MOZART, RACM, RADM2, SAPRC99, CB05, CBMZ) as well as the Master Chemical Mechanism (MCM, U. Leeds). We will use an Observing System Simulation Experiment approach with the MCM prediction as 'nature' or 'true' state, assimilating idealized synthetic observations (from MCM) into the different ‚lumped' mechanisms under various environments. Two approaches to estimate the sensitivity of the chemical system will be compared: 1) adjoint: using Jacobians computed by KPP and 2) ensemble: by perturbing emissions, temperature, photolysis rates, entrainment, etc., in

  2. Chemical Composition and Disruption of Quorum Sensing Signaling in Geographically Diverse United States Propolis

    Directory of Open Access Journals (Sweden)

    Michael A. Savka

    2015-01-01

    Full Text Available Propolis or bee glue has been used for centuries for various purposes and is especially important in human health due to many of its biological and pharmacological properties. In this work we showed quorum sensing inhibitory (QSI activity of ten geographically distinct propolis samples from the United States using the acyl-homoserine lactone- (AHL- dependent Chromobacterium violaceum strain CV026. Based on GC-MS chemical profiling the propolis samples can be classified into several groups that are as follows: (1 rich in cinnamic acid derivatives, (2 rich in flavonoids, and (3 rich in triterpenes. An in-depth analysis of the propolis from North Carolina led to the isolation and identification of a triterpenic acid that was recently isolated from Hondurian propolis (Central America and ethyl ether of p-coumaric alcohol not previously identified in bee propolis. QSI activity was also observed in the second group US propolis samples which contained the flavonoid pinocembrin in addition to other flavonoid compounds. The discovery of compounds that are involved in QSI activity has the potential to facilitate studies that may lead to the development of antivirulence therapies that can be complementary and/or alternative treatments against antibiotic resistant bacterial pathogens and/or emerging pathogens that have yet to be identified.

  3. Octafluorodirhenate(III) Revisited: Solid-State Preparation, Characterization, and Multiconfigurational Quantum Chemical Calculations.

    Science.gov (United States)

    Mariappan Balasekaran, Samundeeswari; Todorova, Tanya K; Pham, Chien Thang; Hartmann, Thomas; Abram, Ulrich; Sattelberger, Alfred P; Poineau, Frederic

    2016-06-01

    A simple method for the high-yield preparation of (NH4)2[Re2F8]·2H2O has been developed that involves the reaction of (n-Bu4N)2[Re2Cl8] with molten ammonium bifluoride (NH4HF2). Using this method, the new salt [NH4]2[Re2F8]·2H2O was prepared in ∼90% yield. The product was characterized in solution by ultraviolet-visible light (UV-vis) and (19)F nuclear magnetic resonance ((19)F NMR) spectroscopies and in the solid-state by elemental analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy. Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were performed to investigate the molecular and electronic structure, as well as the electronic absorption spectrum of the [Re2F8](2-) anion. The metal-metal bonding in the Re2(6+) unit was quantified in terms of effective bond order (EBO) and compared to that of its [Re2Cl8](2-) and [Re2Br8](2-) analogues. PMID:27171734

  4. 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.

  5. Chemical analysis of Yemeni archaeological cheramics and the Egyptian enigma

    International Nuclear Information System (INIS)

    Archaeological reconnaissance in Yemen produced samples of mediaeval Islamic ceramics in a 100 km2 region. The ceramics dated from 700 A.d. to 1750 A.D. and initial research indicated that they were all locally made products. 12 types of ceramics were selected for sampling on the basis of stylistic decoration. Six laboratory samples of each type were subjected to neutron activation analysis for the short-lived isotope producing elements using the SLOWPOKE reactor at the University of Toronto. A comparison with Egyptian pottery was carried out. The statistical analysis conducted on the Yemeni and Egyptian pottery produced discrete differences in their elemental composition which the archaeologist and the chemical scientist might not otherwise recognise. It is concluded that artifacts must be analyzed with due respect given to the archeological context, the elemental chemistry, and sound statistical procedures. (author)

  6. Statistical sampling and chemical analysis of complex weapon components

    International Nuclear Information System (INIS)

    One of the waste streams generated by nuclear weapon dismantlement programs will be component ''hardware'', including complex electronic assemblies such as: radars, arming/fusing/firing systems, power sources, and use-control and safety systems. Sandia National Laboratories (SNL) has been the design and development laboratory for many of these components and will be responsible for their ultimate disposition. This disposition, whether it be reuse, material recycle, or disposal, will require some level of material characterization and analysis. Previous efforts at developing a process for segregation and characterization of hazardous materials in weapon components have been documented. This paper describes the results of recent activities undertaken in support of the Weapon Hardware Inventory Reduction Effort (WHIRE) at Sandia National Laboratories. These activities have been directed principally towards: The development of a statistically sound sampling plan for chemical analysis of weapon component materials; the development of a non-destructive analytical screening method for determining the Toxicity Characteristic of excess weapon hardware

  7. Chemical Analysis of Wastewater from Unconventional Drilling Operations

    Directory of Open Access Journals (Sweden)

    Jonathan B. Thacker

    2015-04-01

    Full Text Available Trillions of liters of wastewater from oil and gas extraction are generated annually in the US. The contribution from unconventional drilling operations (UDO, such as hydraulic fracturing, to this volume will likely continue to increase in the foreseeable future. The chemical content of wastewater from UDO varies with region, operator, and elapsed time after production begins. Detailed chemical analyses may be used to determine its content, select appropriate treatment options, and identify its source in cases of environmental contamination. In this study, one wastewater sample each from direct effluent, a disposal well, and a waste pit, all in West Texas, were analyzed by gas chromatography-mass spectrometry, inductively coupled plasma-optical emission spectroscopy, high performance liquid chromatography-high resolution mass spectrometry, high performance ion chromatography, total organic carbon/total nitrogen analysis, and pH and conductivity analysis. Several compounds known to compose hydraulic fracturing fluid were detected among two of the wastewater samples including 2-butoxyethanol, alkyl amines, and cocamide diethanolamines, toluene, and o-xylene. Due both to its quantity and quality, proper management of wastewater from UDO will be essential.

  8. Cosmetics chemical composition characterization by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    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 8x1011ncm-2s-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)

  9. Metal Oxide Nanoparticles: The Importance of Size, Shape, Chemical Composition, and Valence State in Determining Toxicity

    Science.gov (United States)

    Dunnick, Katherine

    Nanoparticles, which are defined as a structure with at least one dimension between 1 and 100 nm, have the potential to be used in a variety of consumer products due to their improved functionality compared to similar particles of larger size. Their small size is associated with increased strength, improved catalytic properties, and increased reactivity; however, their size is also associated with increased toxicity in vitro and in vivo. Numerous toxicological studies have been conducted to determine the properties of nanomaterials that increase their toxicity in order to manufacture new nanomaterials with decreased toxicity. Data indicates that size, shape, chemical composition, and valence state of nanomaterials can dramatically alter their toxicity profile. Therefore, the purpose of this dissertation was to determine how altering the shape, size, and chemical composition of various metal oxide nanoparticles would affect their toxicity. Metal oxides are used in variety of consumer products, from spray-sun screens, to food coloring agents; thus, understanding the toxicity of metal oxides and determining which aspects affect their toxicity may provide safe alternatives nanomaterials for continued use in manufacturing. Tungstate nanoparticles toxicity was assessed in an in vitro model using RAW 264.7 cells. The size, shape, and chemical composition of these nanomaterials were altered and the effect on reactive oxygen species and general cytotoxicity was determined using a variety of techniques. Results demonstrate that shape was important in reactive oxygen species production as wires were able to induce significant reactive oxygen species compared to spheres. Shape, size, and chemical composition did not have much effect on the overall toxicity of these nanoparticles in RAW 264.7 cells over a 72 hour time course, implicating that the base material of the nanoparticles was not toxic in these cells. To further assess how chemical composition can affect toxicity

  10. Structure and dynamics of acrolein in 1,3(π,π *) excited electronic states: A quantum-chemical study

    Science.gov (United States)

    Bokareva, O. S.; Bataev, V. A.; Pupyshev, V. I.; Godunov, I. A.

    2009-08-01

    The geometrical structure, conformer energy differences, and conformational and vibrational dynamics of acrolein in 1,3(π,π *) electronic states were investigated using a number of single- and multi-reference quantum-chemical methods. Peculiarities of acrolein in the 1(π,π *) state were described with both conformers being significantly non-planar. A Valence Focal-Point Analysis of the conformer energy difference in the 3(π,π *) state was performed. The coupling of the internal rotation about C sbnd C and C dbnd C bonds with large amplitude molecular motions, such as non-planar distortions of carbonyl, methylene, and methyne fragments was also investigated. The corresponding two-dimensional PES sections were constructed.

  11. Regulation of chemical safety at fuel cycle facilities by the United States Nuclear Regulatory Commission

    International Nuclear Information System (INIS)

    When the U.S. Nuclear Regulatory Commission (NRC) was established in 1975, its regulations were based on radiation dose limits. Chemical hazards rarely influenced NRC regulations. After the Three Mile Island reactor accident in 1979, the NRC staff was directed to address emergency planning at non-reactor facilities. Several fuel cycle facilities were ordered to submit emergency plans consistent with reactor emergency plans because no other guidance was available. NRC published a notice that it was writing regulations to codify the requirements in the Orders and upgrade the emergency plans to address all hazards, including chemical hazards. The legal authority of NRC to regulate chemical safety was questioned. In 1986, an overfilled uranium hexafluoride cylinder ruptured and killed a worker. The NRC staff was directed to address emergency planning for hazardous chemicals in its regulations. The final rule included a requirement for fuel cycle facilities to certify compliance with legislation requiring local authorities to establish emergency plans for hazardous chemicals. As with emergency planning, NRC's authority to regulate chemical safety during routine operations was limited. NRC established memoranda of understanding (MOUs) with other regulatory agencies to encourage exchange of information between the agencies regarding occupational hazards. In 2000, NRC published new, performance-based, regulations for fuel cycle facilities. The new regulations required an integrated safety analysis (ISA) which used quantitative standards to assess chemical exposures. Some unique chemical exposure cases were addressed while implementing the new regulations. In addition, some gaps remain in the regulation of hazardous chemicals at fuel cycle facilities. The status of ongoing efforts to improve regulation of chemical safety at fuel cycle facilities is discussed. (authors)

  12. Analysis of Ukrainian state target program implementation

    Directory of Open Access Journals (Sweden)

    Ya.V. Burіak

    2015-12-01

    Full Text Available The article is dedicated to the analysis of conditions of state target program implementation in Ukraine. The purpose of this article is to determine the main disadvantages and problematic aspects during implementation of target programs which hinder their effectiveness. The statistics data of program implementation efficiency are adduced. Based on these data the conclusions about failure, in most cases, of program aims and, as a result, non-completion of planned efficiency indexes are made. Based on the analysis the author has made conclusions about overall condition of this target programs in Ukraine. It is pointed on the need to revise program financial arrangement by combining identical programs by their purpose. The author gives the proposals that justify the necessity of development and realization of formation of the scientific-methodical approach to the evaluation of effectiveness of state target programs of Ukrainian innovative development. The alternative ways of solving the problems of ineffective implementation of target programs in Ukraine are proposed.

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

    International Nuclear Information System (INIS)

    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 1H-NMR and 13C-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 H2O molecules per formula unit. (orig./EF)

  14. Physical and Chemical Analytical Analysis: A key component of Bioforensics

    Energy Technology Data Exchange (ETDEWEB)

    Velsko, S P

    2005-02-15

    The anthrax letters event of 2001 has raised our awareness of the potential importance of non-biological measurements on samples of biological agents used in a terrorism incident. Such measurements include a variety of mass spectral, spectroscopic, and other instrumental techniques that are part of the current armamentarium of the modern materials analysis or analytical chemistry laboratory. They can provide morphological, trace element, isotopic, and other molecular ''fingerprints'' of the agent that may be key pieces of evidence, supplementing that obtained from genetic analysis or other biological properties. The generation and interpretation of such data represents a new domain of forensic science, closely aligned with other areas of ''microbial forensics''. This paper describes some major elements of the R&D agenda that will define this sub-field in the immediate future and provide the foundations for a coherent national capability. Data from chemical and physical analysis of BW materials can be useful to an investigation of a bio-terror event in two ways. First, it can be used to compare evidence samples collected at different locations where such incidents have occurred (e.g. between the powders in the New York and Washington letters in the Amerithrax investigation) or between the attack samples and those seized during the investigation of sites where it is suspected the material was manufactured (if such samples exist). Matching of sample properties can help establish the relatedness of disparate incidents, and mis-matches might exclude certain scenarios, or signify a more complex etiology of the events under investigation. Chemical and morphological analysis for sample matching has a long history in forensics, and is likely to be acceptable in principle in court, assuming that match criteria are well defined and derived from known limits of precision of the measurement techniques in question. Thus, apart from certain

  15. Benchmarks for the 13C NMR chemical shielding tensors in peptides in the solid state

    Science.gov (United States)

    Czernek, Jiří; Pawlak, Tomasz; Potrzebowski, Marek J.

    2012-02-01

    The benchmark set is proposed, which comprises 126 principal elements of chemical shielding tensors, and the respective isotropic chemical shielding values, of all 42 13C nuclei in crystalline Tyr-D-Ala-Phe and Tyr-Ala-Phe tripeptides with known, but highly dissimilar structures. These data are obtained by both the NMR measurements and the density functional theory in the pseudopotential plane-wave scheme. Using the CASTEP program, several computational strategies are employed, for which the level of agreement between calculations and experiment is established. This set is mainly intended for the validation of methods capable of predicting the 13C NMR parameters in solid-state systems.

  16. Hot QCD equation of state and quark-gluon plasma-- finite quark chemical potential

    CERN Document Server

    Chandra, Vinod

    2008-01-01

    We explore the relevance of a hot QCD equation of state of $O[g^6\\ln(1/g)]$, which has been obtained\\cite{avrn} for non-vanishing quark-chemical potentials to heavy ion collisions. Employing a method proposed in a recent paper \\cite{chandra1}, we use the EOS to determine a host of thermodynamic quantities, the energy density, specific heat, entropy dnesity, and the temperature dependence of screening lengths, with the behaviour of QGP at RHIC and LHC in mind. We also investigate the sensitivity of these observables to the quark chemical potential.

  17. Enabling Collaborative Analysis: State Evaluation Groups, the Electronic State File, and Collaborative Analysis Tools

    International Nuclear Information System (INIS)

    The timely collection and analysis of all safeguards relevant information is the key to drawing and maintaining soundly-based safeguards conclusions. In this regard, the IAEA has made multidisciplinary State Evaluation Groups (SEGs) central to this process. To date, SEGs have been established for all States and tasked with developing State-level approaches (including the identification of technical objectives), drafting annual implementation plans specifying the field and headquarters activities necessary to meet technical objectives, updating the State evaluation on an ongoing basis to incorporate new information, preparing an annual evaluation summary, and recommending a safeguards conclusion to IAEA senior management. To accomplish these tasks, SEGs need to be staffed with relevant expertise and empowered with tools that allow for collaborative access to, and analysis of, disparate information sets. To ensure SEGs have the requisite expertise, members are drawn from across the Department of Safeguards based on their knowledge of relevant data sets (e.g., nuclear material accountancy, material balance evaluation, environmental sampling, satellite imagery, open source information, etc.) or their relevant technical (e.g., fuel cycle) expertise. SEG members also require access to all available safeguards relevant data on the State. To facilitate this, the IAEA is also developing a common, secure platform where all safeguards information can be electronically stored and made available for analysis (an electronic State file). The structure of this SharePoint-based system supports IAEA information collection processes, enables collaborative analysis by SEGs, and provides for management insight and review. In addition to this common platform, the Agency is developing, deploying, and/or testing sophisticated data analysis tools that can synthesize information from diverse information sources, analyze diverse datasets from multiple viewpoints (e.g., temporal, geospatial

  18. Moisture-induced solid state instabilities in α-chymotrypsin and their reduction through chemical glycosylation

    Directory of Open Access Journals (Sweden)

    Solá Ricardo J

    2010-08-01

    Full Text Available Abstract Background Protein instability remains the main factor limiting the development of protein therapeutics. The fragile nature (structurally and chemically of proteins makes them susceptible to detrimental events during processing, storage, and delivery. To overcome this, proteins are often formulated in the solid-state which combines superior stability properties with reduced operational costs. Nevertheless, solid protein pharmaceuticals can also suffer from instability problems due to moisture sorption. Chemical protein glycosylation has evolved into an important tool to overcome several instability issues associated with proteins. Herein, we employed chemical glycosylation to stabilize a solid-state protein formulation against moisture-induced deterioration in the lyophilized state. Results First, we investigated the consequences of moisture sorption on the stability and structural conformation of the model enzyme α-chymotrypsin (α-CT under controlled humidity conditions. Results showed that α-CT aggregates and inactivates as a function of increased relative humidity (RH. Furthermore, α-CT loses its native secondary and tertiary structure rapidly at increasing RH. In addition, H/D exchange studies revealed that α-CT structural dynamics increased at increasing RH. The magnitude of the structural changes in tendency parallels the solid-state instability data (i.e., formation of buffer-insoluble aggregates, inactivation, and loss of native conformation upon reconstitution. To determine if these moisture-induced instability issues could be ameliorated by chemical glycosylation we proceeded to modify our model protein with chemically activated glycans of differing lengths (lactose and dextran (10 kDa. The various glycoconjugates showed a marked decrease in aggregation and an increase in residual activity after incubation. These stabilization effects were found to be independent of the glycan size. Conclusion Water sorption leads to

  19. 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.

  20. Instrumental neutron activation analysis. A valuable link in chemical metrology

    International Nuclear Information System (INIS)

    A systematic experimental approach to the demonstration of viability of instrumental neutron activation analysis (INAA) in chemical metrology is provided. The practical approach was derived from a complete survey of uncertainty components that affect the INAA measurement process. These uncertainty components were classified by their magnitude and origin and subsequently minimized by appropriate steps in the INAA process. The process was tested with the INAA determination of Cr in SRM 1152A stainless steel; the Cr value is certified at 17.76% with an estimated uncertainty of 0.04% (0.23% relative). The INAA results from this procedure are in agreement with these specifications. Similar procedures have been applied to INAA multi-element determinations in a high temperature alloy. Agreement with available consensus values was demonstrated in the alloy. The guidelines on the determination of uncertainty were fully met, providing through INAA a valuable independent non-destructive tool in chemical measurements of metrological value such as required in the CCQM key comparisons. (author)

  1. 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

  2. Do provisions to advance chemical facility safety also advance chemical facility security? An analysis of possible synergies

    DEFF Research Database (Denmark)

    Hedlund, Frank Huess

    2012-01-01

    The European Commission has launched a study on the applicability of existing chemical industry safety provisions to enhancing security of chemical facilities covering the situation in 18 EU Member States. This paper reports some preliminary analytical findings regarding the extent to which...... Infrastructures (ECI Directive) addresses facility security but does not cover the chemical sector. Chemical facility safety at EU level is addressed by way of the Seveso-II Directive. Preliminary estimates by the chemical industry suggest that perhaps 80% of the existing safety measures under Seveso-II would...... existing provisions that have been put into existence to advance safety objectives due to synergy effects could be expected advance security objectives as well. The paper provides a conceptual definition of safety and security and presents a framework of their essential components. Key differences are...

  3. Chemical analysis of ancient relicts in the Milky Way disk

    Directory of Open Access Journals (Sweden)

    Tautvaišienė G.

    2012-02-01

    Full Text Available We present detailed analysis of two groups of F- and G- type stars originally found to have similarities in their orbital parameters. The distinct kinematic properties suggest that they might originate from ancient accretion events in the Milky Way. From high resolution spectra taken with the spectrograph FIES at the Nordic Optical Telescope, La Palma, we determined abundances of oxygen, alpha- and r-process elements. Our results indicate that the sample of investigated stars is chemically homogeneous and the abundances of oxygen, alpha and r-process elements are overabundant in comparison with Galactic disk dwarfs. This provides the additional evidence that those stellar groups had the common formation and possible origin from disrupted satellites.

  4. Do provisions to advance chemical facility safety also advance chemical facility security? An analysis of possible synergies

    DEFF Research Database (Denmark)

    Hedlund, Frank Huess

    The European Commission has launched a study on the applicability of existing chemical industry safety provisions to enhancing security of chemical facilities covering the situation in 18 EU Member States. This paper reports some preliminary analytical findings regarding the extent to which...... exist at the mitigation level. At the strategic policy level, synergies are obvious. The security of chemical facilities is important. First, facilities with large inventories of toxic materials could be attractive targets for terrorists. The concern is sabotage causing an intentional release that could...

  5. Urban Regional Traffic State Analysis Software System Emphasizing Pattern Transition

    OpenAIRE

    Longfei Wang; Yang Li; Song Zhang; Qing Zhang

    2013-01-01

    Urban traffic state evolution analysis is very significant and constructive for traffic guidance and control. In this paper, firstly, a quantitative method for analyzing regional traffic state evolution was proposed by constructing traffic state pattern transition network to mine regional traffic state information and state pattern transition characteristics from massive data. Secondly, a GIS-based urban regional traffic state analysis soft ware system URTSAS based on the method was designed ...

  6. 化学物相分析法测定瓮福磷尾矿中钙镁磷元素形态含量%Determination of Occurrence States of Calcium, Magnesium, Phosphorus in Wengfu Phosphorus Tailings by Chemical Phase Analysis

    Institute of Scientific and Technical Information of China (English)

    金绍祥

    2011-01-01

    用化学物相分析法测定瓮福磷尾矿中钙、镁、磷元素形态含量.结果表明,磷尾矿中钙主要以白云石的形式赋存,并有少量以方解石、磷酸盐形式存在;镁主要以白云石的形式赋存,并有少量以磷酸盐、硅酸盐形式存在;磷主要以磷灰石的形式赋存,并有少量以铁氧化物、独居石、磷钇矿形式存在.各元素形态加标回收率为97.6%~107.2%,相对标准偏差(RSD,n=12)为0.77%~4.85%.各元素形态分析结果表现出较好的稳定性,表明采用化学物相分析法测定瓮福磷尾矿中钙、镁、磷元素形态含量结果准确可靠.%The contents of calcium, magnesium and phosphorus species in Wengfu Phosphorus Tailings were determined by chemical phase analysis method. The results showed that calcium existed mainly as dolomite with a few as calcite and phosphate , magnesium existed mainly as dolomite with a few as phosphate and silicate and phosphorus existed mainly as phosphate with a few as iron oxides, monazite and xenotime. Standard recoveries for all species of the elements were 97.6% - 107. 2% with precision of 0. 77% -4. 85% RSD (n = 12). Speciation analysis results presented a good stability, which indicated that the analytical results of ccurrence states of Ca, Mg and P in Wengfu Phosphorus Tailings by chemical phase analysis method were accurate and reliable.

  7. Chemical states of fission products in irradiated uranium-plutonium mixed oxide fuel

    International Nuclear Information System (INIS)

    The chemical states of fission products (FPs) in irradiated uranium-plutonium mixed oxide (MOX) fuel for the light water reactor (LWR) were estimated by thermodynamic equilibrium calculations on system of fuel and FPs by using ChemSage program. A stoichiometric MOX containing 6.1 wt. percent PuO2 was taken as a loading fuel. The variation of chemical states of FPs was calculated as a function of oxygen potential. Some pieces of information obtained by the calculation were compared with the results of the post-irradiation examination (PIE) of UO2 fuel. It was confirmed that the multicomponent and multiphase thermodynamic equilibrium calculation between fuel and FPs system was an effective tool for understanding the behavior of FPs in fuel. (author)

  8. Microarray Technology for Major Chemical Contaminants Analysis in Food: Current Status and Prospects

    Directory of Open Access Journals (Sweden)

    Xiaoxia Ding

    2012-07-01

    Full Text Available 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.

  9. Applications for Solid-State Joints in the chemical process industry

    Science.gov (United States)

    Goin, R. David

    2008-11-01

    Two forms of solid-state joining of tubing are explored here for use in the chemical process industry and other applications. Extrusion bonding consists of diffusion bonding an inner seamless tube of one material to an outer seamless tube of another material. Inertia welding consists of rotating one tube while pressing a second stationary tube into the first. In both cases, a very strong and robust metallurgical bond can result. This paper explores the testing and properties of such metallurgical bonds.

  10. Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Natalia Abramova

    2015-06-01

    Full Text Available Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH.

  11. Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors

    OpenAIRE

    Natalia Abramova; Andrey Bratov

    2015-01-01

    Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH.

  12. Analysis Of Samples From Tank 6F Chemical Cleaning

    International Nuclear Information System (INIS)

    Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. In mechanical sludge removal, personnel add liquid (e.g., inhibited water or supernate salt solution) to the tank to form a slurry. They mix the liquid and sludge with pumps, and transfer the slurry to another tank for further processing. Mechanical sludge removal effectively removes the bulk of the sludge from a tank, but is not able to remove all of the sludge. In Tank 6F, SRR estimated a sludge heel of 5,984 gallons remained after mechanical sludge removal. To remove this sludge heel, SRR performed chemical cleaning. The chemical cleaning included two oxalic acid strikes, a spray wash, and a water wash. SRR conducted the first oxalic acid strike as follows. Personnel added 110,830 gallons of 8 wt % oxalic acid to Tank 6F and mixed the contents of Tank 6F with two submersible mixer pumps (SMPs) for approximately four days. Following the mixing, they transferred 115,903 gallons of Tank 6F material to Tank 7F. The SMPs were operating when the transfer started and were shut down approximately five hours after the transfer started. SRR collected a sample of the liquid from Tank 6F and submitted it to SRNL for analysis. Mapping of the tank following the transfer indicated that 2,400 gallons of solids remained in the tank. SRR conducted the second oxalic acid strike as follows. Personnel added 28,881 gallons of 8 wt % oxalic acid to Tank 6F. Following the acid addition, they visually inspected the tank and transferred 32,247 gallons of Tank 6F material to Tank 7F. SRR collected a sample of the liquid from Tank 6F and submitted it to SRNL for analysis. Mapping of the tank following the transfer indicated that 3,248 gallons of solids remained in the tank. Following the oxalic acid strikes, SRR performed Spray Washing with oxalic acid to remove waste collected on internal structures, cooling coils, tank top internals, and tank

  13. Physico-Chemical Analysis of Selected Groundwater Samples of Inkollu Mandal, Prakasam District, Andhra Pradesh, India

    Directory of Open Access Journals (Sweden)

    G. Arun Kumar

    2015-04-01

    Full Text Available Physico-chemical parameters of groundwater quality based on Physic-chemical parameters at Inkollu mandal, Prakasam district, Andhra Pradesh, India have been taken up to evaluate its suitability for Drinking purpose. Nine ground water samples were collected from different places of Inkollu mandal of Prakasam district. The quality analysis has been made through the pH, EC, TDS, Total Hardness, Sodium, Potassium, Calcium, Magnesium, Chloride, Sulphate, Nitrate, Fluoride and Iron. By observing the results, it was shown that the parameters from the water samples were compared with WHO (World Health Organization and BIS (Bureau of Indian Standards, USPH (United state Public health for ground water .The results revealed that some parameters were in high concentration and quality of the potable water has deteriorated to a large extent at some sampling locations.

  14. Octafluorodirhenate(III) Revisited: Solid-State Preparation, Characterization, and Multiconfigurational Quantum Chemical Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Mariappan Balasekaran, Samundeeswari; Todorova, Tanya K.; Pham, Chien Thang; Hartmann, Thomas; Abram, Ulrich; Sattelberger, Alfred P.; Poineau, Frederic

    2016-06-06

    A simple method for the high-yield preparation of (NH4)2[Re2F8]· 2H2O has been developed that involves the reaction of (n-Bu4N)2[Re2Cl8] with molten ammonium bifluoride (NH4HF2). Using this method, the new salt [NH4]2[Re2F8]·2H2O was prepared in ~90% yield. The product was characterized in solution by ultraviolet-visible light (UV-vis) and 19F nuclear magnetic resonance (19F NMR) spectroscopies and in the solid-state by elemental analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy. Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were performed to investigate the molecular and electronic structure, as well as the electronic absorption spectrum of the [Re2F8] 2- anion. The metal-metal bonding in the Re2 6+ unit was quantified in terms of effective bond order (EBO) and compared to that of its [Re2Cl8] 2- and [Re2Br8] 2- analogues.

  15. LIQUIDITY ANALYSIS OF STATE BANK OF INDIA

    Directory of Open Access Journals (Sweden)

    Kumar Gandhi R

    2011-12-01

    Full Text Available Modern customer has a high demand for quality of service than he/she had before. There is an urgent need for improving the customer service levels currently provided in the banking industry. Banks need to understand, foresee, the needs and expected levels of customer support which the customer expects when he/she steps into the branch and strive to stand up and excel in providing the service and making banking a truly delightful experience. The banker should change his/her agenda from Customer Satisfaction to Customer delight and then march towards Customer Ecstasy. This will be possible by maintaining the financial soundness of the firm. In this connection it has been given importance through this study. Since most of the Banking slightly deviate into the other areas like insurance, financial services and modern banking services such as Advisory services, Agent for receivables, custodian, instant loan provider, Forfeiter services and factoring services. A conscious attempt has been made to analysis the liquidity of state bank of India (SBI. The present study aimed to understand the financial soundness of the bank, the ratio analysis taken as tool. In this research work the secondary data mainly used, it has been collected in the form of the company manuals, Balance sheets and other documents. The data analyzed by some of the statistical tools such as ANOVA test and Multi variate test is used to analyze the interferences about the operating efficiency.

  16. Advances in Mid-Infrared Spectroscopy for Chemical Analysis.

    Science.gov (United States)

    Haas, Julian; Mizaikoff, Boris

    2016-06-12

    Infrared spectroscopy in the 3-20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review. PMID:27070183

  17. Advances in Mid-Infrared Spectroscopy for Chemical Analysis

    Science.gov (United States)

    Haas, Julian; Mizaikoff, Boris

    2016-06-01

    Infrared spectroscopy in the 3–20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

  18. 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. PMID:21165873

  19. Chemical analysis and potential health risks of hookah charcoal.

    Science.gov (United States)

    Elsayed, Yehya; Dalibalta, Sarah; 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. PMID:27343945

  20. Chemical analysis of Argonne premium coal samples. Bulletin

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, C.A.

    1997-11-01

    Contents: The Chemical Analysis of Argonne Premium Coal Samples: An Introduction; Rehydration of Desiccated Argonne Premium Coal Samples; Determination of 62 Elements in 8 Argonne Premium Coal Ash Samples by Automated Semiquantitative Direct-Current Arc Atomic Emission Spectrography; Determination of 18 Elements in 5 Whole Argonne Premium Coal Samples by Quantitative Direct-Current Arc Atomic Emission Spectrography; Determination of Major and Trace Elements in Eight Argonne Premium Coal Samples (Ash and Whole Coal) by X-Ray Fluorescence Spectrometry; Determination of 29 Elements in 8 Argonne Premium Coal Samples by Instrumental Neutron Activation Analysis; Determination of Selected Elements in Coal Ash from Eight Argonne Premium Coal Samples by Atomic Absorption Spectrometry and Atomic Emission Spectrometry; Determination of 25 Elements in Coal Ash from 8 Argonne Premium Coal Samples by Inductively Coupled Argon Plasma-Atomic Emission Spectrometry; Determination of 33 Elements in Coal Ash from 8 Argonne Premium Coal Samples by Inductively Coupled Argon Plasma-Mass Spectrometry; Determination of Mercury and Selenium in Eight Argonne Premium Coal Samples by Cold-Vapor and Hydride-Generation Atomic Absorption Spectrometry; Determinaton of Carbon, Hydrogen, and Nitrogen in Eight Argonne Premium Coal Samples by Using a Gas Chromatographic Analyzer with a Thermal Conductivity Detector; and Compilation of Multitechnique Determinations of 51 Elements in 8 Argonne Premium Coal Samples.

  1. Correlação entre a resposta do algodoeiro à adubação fosfatada e a análise química do solo, nas condições do Estado de São Paulo Correlation between cotton responses to phosphorous fertilization and chemical analysis on State of São Paulo soils

    Directory of Open Access Journals (Sweden)

    Milton Geraldo Fuzatto

    1966-01-01

    Full Text Available Uma regressão múltipla, descrevendo a resposta do algodoeiro à adubação fosfatada em função do teor de PO4-3 solúvel e da acidez do solo, aquêle dado por dois métodos de análise, é discutida em 126 experimentos de adubação realizados em vários tipos de solo do Estado de São Paulo. Em geral, o índice de acidez se mostrou tão importante quanto o teor de fósforo solúvel, para explicar o efeito da adubação fosfatada, sendo maiores êstes, em solos mais ácidos. Os dois métodos de análise de fósforo no solo, utilizando respectivamente ácido sulfúrico 0,05 Ne ácido oxálico + oxalato de potássio N,como soluções extratoras, foram comparados no estudo das correlações. A separação dos ensaios em dois grupos, se conduzidos em solos argilosos ou arenosos, revelou interação entre os métodos de análise e êsses grupos, o que possibilitou apreciar as vantagens e inconvenientes de cada método, nas condições estudadas.In this paper the correlation between cotton responses to phosphorus application and chemical analysis of soils is discussed, based on 126 experiments conducted in the State of São Paulo. The results indicate the possibilities of estimating the effects due to phosphorous fertilization on the basis of the amount of soluble phosphorus and soil acidity, by means of a multiple regression equation. Two methods of chemical analysis, utilizing respectively sulphuric acid 0.05 Nand oxalic acid + potassium oxalate N,as extractor of phosphorus, were compared in the correlation studies. Both method show advantages and inconvenients, mainly when applied specifically to the clay or sandy soils. It was suggested that another method, with extraction capacity intermediate to those discussed, would be more appropriate for fertilizer recomen-dations, irrespective of the soil types considered.

  2. 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.

  3. 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

  4. 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

  5. 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...

  6. Emergence of a super-synchronized mobbing state in a large population of coupled chemical oscillators

    Science.gov (United States)

    Ghoshal, Gourab; Muñuzuri, Alberto P.; Pérez-Mercader, Juan

    2016-01-01

    Oscillatory phenomena are ubiquitous in Nature. The ability of a large population of coupled oscillators to synchronize constitutes an important mechanism to express information and establish communication among members. To understand such phenomena, models and experimental realizations of globally coupled oscillators have proven to be invaluable in settings as varied as chemical, biological and physical systems. A variety of rich dynamical behavior has been uncovered, although usually in the context of a single state of synchronization or lack thereof. Through the experimental and numerical study of a large population of discrete chemical oscillators, here we report on the unexpected discovery of a new phenomenon revealing the existence of dynamically distinct synchronized states reflecting different degrees of communication. Specifically, we discover a novel large-amplitude super-synchronized state separated from the conventionally reported synchronized and quiescent states through an unusual sharp jump transition when sampling the strong coupling limit. Our results assume significance for further elucidating globally coherent phenomena, such as in neuropathologies, bacterial cell colonies, social systems and semiconductor lasers.

  7. Sensitivity Amplification in the Phosphorylation-Dephosphorylation Cycle: Nonequilibrium steady states, chemical master equation and temporal cooperativity

    CERN Document Server

    Ge, Hao

    2009-01-01

    A new type of cooperativity termed temporal cooperativity [Biophys. Chem. 105 585-593 (2003), Annu. Rev. Phys. Chem. 58 113-142 (2007)], emerges in the signal transduction module of phosphorylation-dephosphorylation cycle (PdPC). It utilizes multiple kinetic cycles in time, in contrast to allosteric cooperativity that utilizes multiple subunits in a protein. In the present paper, we thoroughly investigate both the deterministic (microscopic) and stochastic (mesoscopic) models, and focus on the identification of the source of temporal cooperativity via comparing with allosteric cooperativity. A thermodynamic analysis confirms again the claim that the chemical equilibrium state exists if and only if the phosphorylation potential $\\triangle G=0$, in which case the amplification of sensitivity is completely abolished. Then we provide comprehensive theoretical and numerical analysis with the first-order and zero-order assumptions in phosphorylation-dephosphorylation cycle respectively. Furthermore, it is interesti...

  8. Methodology for the physical and chemical exergetic analysis of steam boilers

    International Nuclear Information System (INIS)

    This paper presents a framework of thermodynamic, energy and exergy, analyses of industrial steam boilers. Mass, energy, and exergy analysis were used to develop a methodology for evaluating thermodynamic properties, energy and exergy input and output resources in industrial steam boilers. Determined methods make available an analytic procedure for the physical and chemical exergetic analysis of steam boilers for appropriate applications. The energy and exergy efficiencies obtained for the entire boiler was 69.56% and 38.57% at standard reference state temperature of 25 °C for an evaporation ratio of 12. Chemical exergy of the material streams was considered to offer a more comprehensive detail on energy and exergy resource allocation and losses of the processes in a steam boiler. - Highlights: ► We evaluated thermodynamic properties and performance variables associated with material streams. ► We analysed resources allocation, and magnitude of exergetic losses in steam boilers. ► Chemical exergy of material streams contributed to improved exergy values. ► High operational parameter will lead to higher boiler exergy. ► Exergy destroyed was higher in the combustion as against the heat exchanging unit

  9. Chimera and phase-cluster states in populations of coupled chemical oscillators

    Science.gov (United States)

    Tinsley, Mark R.; Nkomo, Simbarashe; Showalter, Kenneth

    2012-09-01

    Populations of coupled oscillators may exhibit two coexisting subpopulations, one with synchronized oscillations and the other with unsynchronized oscillations, even though all of the oscillators are coupled to each other in an equivalent manner. This phenomenon, discovered about ten years ago in theoretical studies, was then further characterized and named the chimera state after the Greek mythological creature made up of different animals. The highly counterintuitive coexistence of coherent and incoherent oscillations in populations of identical oscillators, each with an equivalent coupling structure, inspired great interest and a flurry of theoretical activity. Here we report on experimental studies of chimera states and their relation to other synchronization states in populations of coupled chemical oscillators. Our experiments with coupled Belousov-Zhabotinsky oscillators and corresponding simulations reveal chimera behaviour that differs significantly from the behaviour found in theoretical studies of phase-oscillator models.

  10. Biomass Feedstock Availability in the United States: 1999 State Level Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Marie E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perlack, Robert L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Turhollow, Anthony [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); de la Torre Ugarte, Daniel [Univ. of Tennessee, Knoxville, TN (United States); Becker, Denny A. [Science Applications International Corporation, Oak Ridge, TN (United States); Graham, Robin L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Slinsky, Stephen E. [Univ. of Tennessee, Knoxville, TN (United States); Ray, Daryll E. [Univ. of Tennessee, Knoxville, TN (United States)

    2000-01-01

    Interest in using biomass feedstocks to produce power, liquid fuels, and chemicals in the U.S. is increasing. Central to determining the potential for these industries to develop is an understanding of the location, quantities, and prices of biomass resources. This paper describes the methodology used to estimate biomass quantities and prices for each state in the continental United States.

  11. Quantum chemical computations, vibrational spectroscopic analysis and antimicrobial studies of 2,3-Pyrazinedicarboxylic acid.

    Science.gov (United States)

    Beaula, T Joselin; Packiavathi, A; Manimaran, D; Joe, I Hubert; Rastogi, V K; Jothy, V Bena

    2015-03-01

    Density Functional Theory (DFT) calculations at B3PW91 level with 6-311G (d) basis sets were carried out for 2,3-Pyrazinedicarboxylic acid (PDCA) to analyze in detail the equilibrium geometries and vibrational spectra. Calculations reveal that the optimized geometry closely resembles the experimental XRD data. Vibrational spectra were analyzed on the basis of potential energy distribution (PED) of each vibrational mode, which provides quantitative as well as qualitative interpretation of IR and Raman spectra. Information about size, shape, charge density distribution and site of chemical reactivity of the molecule were obtained by mapping electron density isosurface with the electrostatic potential surface (ESP). Based on optimized ground state geometries, NBO analysis was performed to study donor-acceptor (bond-antibond) interactions. TD-DFT analysis was also performed to calculate energies, oscillator strength of electronic singlet-singlet transitions and the absorption wavelengths. The (13)C and (1)H nuclear magnetic resonance (NMR) chemical shifts of the molecule in the ground state were calculated by gauge independent atomic orbital (GIAO) method and compared with the experimental values. PDCA was screened for its antimicrobial activity and found to exhibit antifungal and antibacterial effects. Molecular docking was also performed for the different receptors. PMID:25544188

  12. Analysis of equations of state for ICF

    International Nuclear Information System (INIS)

    In the field of inertial confinement fusion (ICF), numerical simulation plays a very important role reproducing real results with a good accuracy. Once considered the needed simplificative approximations, it is obtained and equation system that has to be solved in a more or less complex way. Anyway these simulation codes have to fit the behaviour of real materials with the help of some flexible parameters. In the case of fluid dynamics, the key to fit the equation system to the real material behaviour are the equations of state (EOS) involved in the problem. This is why there is an actual need of using accurate data in order to obtain results that match the real behaviour of materials. Nowadays there are several available sources of real EOS data. These sources are based either in theoretical models fixed with experimental results or in analytical approximations to those models. In this article a comparative analysis is made between two of the most used EOS data sources in simulations. The aim of this work is to check the quality of these data that is commonly used and on which the accuracy of the results depend. (Author) 3 refs

  13. Feasible logic Bell-state analysis with linear optics.

    Science.gov (United States)

    Zhou, Lan; Sheng, Yu-Bo

    2016-01-01

    We describe a feasible logic Bell-state analysis protocol by employing the logic entanglement to be the robust concatenated Greenberger-Horne-Zeilinger (C-GHZ) state. This protocol only uses polarization beam splitters and half-wave plates, which are available in current experimental technology. We can conveniently identify two of the logic Bell states. This protocol can be easily generalized to the arbitrary C-GHZ state analysis. We can also distinguish two N-logic-qubit C-GHZ states. As the previous theory and experiment both showed that the C-GHZ state has the robustness feature, this logic Bell-state analysis and C-GHZ state analysis may be essential for linear-optical quantum computation protocols whose building blocks are logic-qubit entangled state. PMID:26877208

  14. State of the Climate - Global Analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The State of the Climate is a collection of periodic summaries recapping climate-related occurrences on both a global and national scale. The State of the Climate...

  15. EDXRF quantitative analysis of chromophore chemical elements in corundum samples.

    Science.gov (United States)

    Bonizzoni, L; Galli, A; Spinolo, G; Palanza, V

    2009-12-01

    Corundum is a crystalline form of aluminum oxide (Al(2)O(3)) and is one of the rock-forming minerals. When aluminum oxide is pure, the mineral is colorless, but the presence of trace amounts of other elements such as iron, titanium, and chromium in the crystal lattice gives the typical colors (including blue, red, violet, pink, green, yellow, orange, gray, white, colorless, and black) of gemstone varieties. The starting point for our work is the quantitative evaluation of the concentration of chromophore chemical elements with a precision as good as possible to match the data obtained by different techniques as such as optical absorption photoluminescence. The aim is to give an interpretation of the absorption bands present in the NIR and visible ranges which do not involve intervalence charge transfer transitions (Fe(2+) --> Fe(3+) and Fe(2+) --> Ti(4+)), commonly considered responsible of the important features of the blue sapphire absorption spectra. So, we developed a method to evaluate as accurately as possible the autoabsorption effects and the secondary excitation effects which frequently are sources of relevant errors in the quantitative EDXRF analysis. PMID:19821113

  16. Method of chemical analysis of silicate rocks (1962)

    International Nuclear Information System (INIS)

    A rapid method of analysis for the physical and chemical determination of the major constituents of silicate rocks is described. Water losses at 100 deg. C and losses of volatile elements at 1000 deg. C are estimated after staying in oven for these temperatures, or by mean of a thermo-balance. The determination of silica is made by a double insolubilization with hydrochloric acid on attack solution with sodium carbonate; total iron and aluminium, both with calcium and magnesium, after ammoniacal precipitation of Fe and Al, are determined on the filtration product of silica by titrimetry-photometry of their complexes with EDTA. The alkalis Na and K by flame spectrophotometry, Mn by colorimetry of the permanganate, and Ti by mean of his complex with H2O2, are determined on fluosulfuric attack solution. Phosphorus is determined by his complex with 'molybdenum blue' on a fluoro-nitro-boric attack solution; iron is estimated by potentiometry, with the help of bichromate on hydrofluoric solution. (author)

  17. A spectroscopic analysis of the chemically peculiar star HD207561

    CERN Document Server

    Joshi, S; Martinez, P; Sachkov, M; Joshi, Y C; Seetha, S; Chakradhari, N K; Mary, D L; Girish, V; Ashoka, B N

    2012-01-01

    In this paper we present a high-resolution spectroscopic analysis of the chemically peculiar star HD207561. During a survey programme to search for new roAp stars in the Northern hemisphere, Joshi et al. (2006) observed significant photometric variability on two consecutive nights in the year 2000. The amplitude spectra of the light curves obtained on these two nights showed oscillations with a frequency of 2.79 mHz [P~6-min]. However, subsequent follow-up observations could not confirm any rapid variability. In order to determine the spectroscopic nature of HD207561, high-resolution spectroscopic and spectro-polarimetric observations were carried out. A reasonable fit of the calculated Hbeta line profile to the observed one yields the effective temperature (Teff) and surface gravity (log g) as 7300 K and 3.7 dex, respectively. The derived projected rotational velocity (vsin i) for HD207561 is 74 km/sec indicative of a relatively fast rotator. The position of HD207561 in the H-R diagram implies that this is s...

  18. Similarity Analysis of Cable Insulations by Chemical Test

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Analysis of chemical bonding by means of reduced density matrices

    OpenAIRE

    Álvarez Boto, Roberto

    2013-01-01

    The modern Theory of Chemical Bonding may be well understood as the study of reduced density matrices (RDMs) in real space regions to get new insights of the chemical bond. Although, much work has been widely used to understand chemical bonding from one-electron density, include correlation effects requires the access to higher order densities. Based on the cumulant expansion of the RDMs, a set of bonding indices which may decomposed into one-electron component may be defined. Each comp...

  1. TECHNO-ECONOMIC ANALYSIS OF MODERNIZATION FOR CHEMICAL EQUIPMENT

    OpenAIRE

    Задольський, Аркадій Михайлович

    2015-01-01

    Industry of Ukraine is currently in a very difficult situation. This fully relates to the chemical industry. The real way to overcome negative developments, in the chemical industry, is improving its material base and objects of fixed assets. First of all, need improvement, machinery and equipment (chemical equipment). This important problem can be solved by upgrading existing equipment. In order to choose the most efficient option for replacement of obsolete equipment, should apply the techn...

  2. LSENS: A General Chemical Kinetics and Sensitivity Analysis Code for homogeneous gas-phase reactions. Part 3: Illustrative test problems

    Science.gov (United States)

    Bittker, David A.; Radhakrishnan, Krishnan

    1994-01-01

    LSENS, the Lewis General Chemical Kinetics and Sensitivity Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 3 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 3 explains the kinetics and kinetics-plus-sensitivity analysis problems supplied with LSENS and presents sample results. These problems illustrate the various capabilities of, and reaction models that can be solved by, the code and may provide a convenient starting point for the user to construct the problem data file required to execute LSENS. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions.

  3. Two dimensional solid state NMR methods applied to whole coals and chemically modified coals

    Energy Technology Data Exchange (ETDEWEB)

    Zilm, K.W.; Webb, G.G.; Millar, J.M.

    1987-04-01

    Two dimensional NMR methods have been shown to provide a much finer accounting of the functional types present in coals than by CPMAS spectroscopy alone. The ADIPSHIFT method has been shown to be at least as quantitative as CPMAS both in theory and experimentally. The method gives reliable distributions of carbons with differing multiplicities which is useful in identifying different functionalities that overlap in chemical shift. Recent studies of a model system indicate that the connectivity of the different groups in chemically modified coals should be obtainable from solid state COSY and NOESY experiments. This type of information will provide a very accurate picture of the structure of the alkylated sites and the substitution patterns surrounding them.

  4. A Steady-State Approximation to the Two-Dimensional Master Equation for Chemical Kinetics Calculations.

    Science.gov (United States)

    Nguyen, Thanh Lam; Stanton, John F

    2015-07-16

    In the field of chemical kinetics, the solution of a two-dimensional master equation that depends explicitly on both total internal energy (E) and total angular momentum (J) is a challenging problem. In this work, a weak-E/fixed-J collisional model (i.e., weak-collisional internal energy relaxation/free-collisional angular momentum relaxation) is used along with the steady-state approach to solve the resulting (simplified) two-dimensional (E,J)-grained master equation. The corresponding solutions give thermal rate constants and product branching ratios as functions of both temperature and pressure. We also have developed a program that can be used to predict and analyze experimental chemical kinetics results. This expedient technique, when combined with highly accurate potential energy surfaces, is cable of providing results that may be meaningfully compared to experiments. The reaction of singlet oxygen with methane proceeding through vibrationally excited methanol is used as an illustrative example. PMID:25815602

  5. Effects of Different Soil Management Systems in the Chemical Properties in the Coastal Plains of State Paraiba

    Directory of Open Access Journals (Sweden)

    Iêde de Brito Chaves

    2011-11-01

    Full Text Available This study evaluated the chemical characteristics of soils under different management systems, i.e., the culture of sugar cane with and without vinasse compared to forest area in the Coastal Plains ofState Paraiba. For each management system were opened five profiles occurring in the same soil class, dystrophic Ultisol grayish. In each profile, the soil samples were collected at 0-5, 5-10, 10-20 and 20-40 cm depths. These samples, after being air dried and passed through a sieve of 2 mm, were characterized chemically. Data were analyzed using descriptive statistics, analysis of variance and Tukey test at 5% probability. The pH, electrical conductivity, exchangeable aluminum, potential acidity and phosphorus results, in relation to soil management, were significantly affected; in relation to depth, there was a significant effect on the pH results and on the electrical conductivity, calcium, sodium, potassium, potential acidity and P results. However, for area x depths there was a significant difference only for aluminum, potential acidity and phosphorus contents. The results of this study show that treatment with vinasse application promotes improvements in soil chemical properties such as pH increases and the availability of K and P in the surface layers of soil.

  6. Study on Chemical Structures of Tetrafluoroethylene-Perfluoro-Alkyl-Vinylether Copolymer by EB-Irradiation in the Molten State

    International Nuclear Information System (INIS)

    Perfluorinated polymers such as tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA) with remarkable chemical durability and thermal stability have been applied for industry. However, PFA has been classified to be typical radiation-degradable polymer. In our previous work, it has been found that crosslinked PFA has been obtained by irradiation under oxygen-free atmosphere in its molten state. In this study, the change of thermo-physical properties and the chemical structures of crosslinked PFA were studied by DSC and 19F-NMR. PFA was irradiated by soft electron beam (soft-EB) under nitrogen atmosphere at 583 K±3 K. By DSC analysis, the melting temperature (Tm) shifted to lower temperatures, and crystallinity decreased with increasing dose. Of course, in the case of room temperature irradiation, Tms were hardly changed, and crystallinity increased with increasing dose. For 19F-NMR spectroscopy, the several new signals, which should be due to the changed chemical structures, were observed besides the intense peak of CF2 at -124 ppm. The detected new signals assigned to the tertiary carbon (CF) group with Y-type crosslinking site and fluoro-propylene site, and chain end group, respectively. That is, it was found that the Y-type crosslinking reactions and chain scission should occur simultaneously in the melting temperature irradiation. The crosslinking density calculated by concentration of CF with Y-type crosslinking site increased with increasing of dose. The crosslinking density estimated for the 1200 kGy irradiated PFA showed about 1.03%

  7. Recurrence quantification analysis of chimera states

    Energy Technology Data Exchange (ETDEWEB)

    Santos, M.S. [Pós-Graduação em Ciências/Física, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Szezech, J.D., E-mail: jdanilo@gmail.com [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Batista, A.M., E-mail: antoniomarcosbatista@gmail.com [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, 05315-970, São Paulo, SP (Brazil); Viana, R.L.; Lopes, S.R. [Departamento de Física, Universidade Federal do Paraná, 81531-990, Curitiba, PR (Brazil)

    2015-10-02

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse. - Highlights: • Chimera states have been found in various physical systems. • Recurrence plots is a graphical method useful to locate recurring patterns. • We used recurrence plots to identify the chimera states. • We show also the recurrence plots can identify the chimera collapse.

  8. Recurrence quantification analysis of chimera states

    International Nuclear Information System (INIS)

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse. - Highlights: • Chimera states have been found in various physical systems. • Recurrence plots is a graphical method useful to locate recurring patterns. • We used recurrence plots to identify the chimera states. • We show also the recurrence plots can identify the chimera collapse

  9. In vitro chemical and cellular tests applied to uranium trioxide with different hydration states

    International Nuclear Information System (INIS)

    A simple and rapid in vitro chemical solubility test applicable to industrial uranium trioxide (UO3) was developed together with two in vitro cellular tests using rat alveolar macrophages maintained either in gas phase or in alginate beads at 37 degrees C. Industrial UO3 was characterized by particle size, X-ray, and IR spectra, and chemical transformation (e.g., aging and hydration of the dust) was also studied. Solvents used for the in vitro chemical solubility study included carbonates, citrates, phosphates, water, Eagle's basal medium, and Gamble's solution (simulated lung fluid), alone, with oxygen, or with superoxide ions. Results, expressed in terms of the half-time of dissolution, according to International Commission on Radiological Protection (ICRP) classification (D,W,Y), varied for different hydration states of UO3, showing a lower solubility of hydrated UO3 in solvents compared to basic UO3 or UO3 heated at 450 degrees C. Two in vitro cellular tests on cultured rat alveolar macrophages (cells maintained in gas phase and cells immobilized in alginate beads) were used on the same UO3 samples and generally showed a lower solution transfer rate in the presence of macrophages than in the culture medium alone. The results of in vitro chemical and cellular tests were compared, with four main conclusions; a good reproducibility of the three tests in Eagle's basal medium of the effect of hydration state on solubility, the classification of UO3 in terms of ICRP solubility criteria, and the ability of macrophoges to decrease uranium solubility in medium. 16 refs., 3 figs., 4 tabs

  10. Análise de agrupamento, com base na composição físico-química, de amostras de méis produzidos por Apis mellifera L. no Estado de São Paulo Cluster analysis, with basis in physico-chemical composition, of samples of honey produced by Apis mellifera L. in São Paulo State

    Directory of Open Access Journals (Sweden)

    Luís Carlos Marchini

    2005-03-01

    Full Text Available A composição do mel depende, basicamente, da composição do néctar de cada espécie vegetal produtora, conferindo-lhe características específicas enquanto que as condições climáticas e o manejo do apicultor têm influência menor sobre essas características. A presente pesquisa, desenvolvida com amostras de méis de Apis mellifera coletadas diretamente dos produtores de 84 municípios do Estado de São Paulo teve o objetivo de verificar, com base em características físico-químicas, como se agrupam as amostras de méis silvestres e de eucaliptos. Dentre as 121 amostras de méis analisadas as de eucaliptos e as silvestres formam grupos distintos quanto aos caracteres físico-químicos, o que confirma que a origem floral interfere decisivamente nas características dos méis. Pela análise dos componentes principais, pode-se verificar que os caracteres que mais influenciaram no agrupamentos das amostras de méis foram condutividade elétrica e quantidade de K, no eixo X e índice de formol e umidade, no eixo Y.The honey composition depends, basically, of the nectar composition of each vegetal species. This composition confer to it specific characteristics while that the climatic conditions and the beekeeper handling have lesser influence on these features. The present research, developed with samples of Apis mellifera honeys, collected directly of the producers from 84 locations of the State of São Paulo, Brazil, had the objective of verifying, on the basis of physico-chemical characteristics, as the samples of wild and Eucalyptus honeys are grouped. Amongst the 121 samples analyzed the wild and Eucalyptus honeys form distinct groups with basis of the physico-chemical characteristics, what confirms that the floral origin intervenes decisively with the honey characteristics. For the analysis of the main components, it can be verified that the characters that had more influenced in the groupings of the honey samples were the electric

  11. Design of sustainable chemical processes: Systematic retrofit analysis, generation and evaluation alternatives

    DEFF Research Database (Denmark)

    Carvalho, Ana; Gani, Rafiqul; Matos, Henrique

    2008-01-01

    The objective of this paper is to present a generic and systematic methodology for identifying the feasible retrofit design alternatives of any chemical process. The methodology determines a set of mass and energy indicators from steady-state process data, establishes the operational and design...... targets, and through a sensitivity-based analysis, identifies the design alternatives that can match a set of design targets. The significance of this indicator-based method is that it is able to identify alternatives, where one or more performance criteria (factors) move in the same direction thereby...... eliminating the need to identify trade-off-based solutions. These indicators are also able to reduce (where feasible) a set of safety indicators. An indicator sensitivity analysis algorithm has been added to the methodology to define design targets and to generate sustainable process alternatives. A computer...

  12. Sanitary chemical and bacteriological analysis of drinking water in Kocani

    OpenAIRE

    Panova, Gordana; Panova, Blagica; Panov, Nenad

    2013-01-01

    Acute diseases occur as a result of contamination of drinking water with microorganisms (causes gastrointestinal disease) or contamination with nitrates causes methemoglobinemia in children), pesticides or other chemicals. The occurrence of water-borne infections due to inadequate sanitation, disposal of manure decomposition processing operating system or contamination during distribution. Harmful chemical pollution due to accidents or inadequate distribution system ...

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

    International Nuclear Information System (INIS)

    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

  14. Behaviors of optical and chemical state of Nb+ implanted sapphire after annealing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of the radiation damage of sapphire crystal, produced by implantation with 380 keV Nb+ ion followed by annealing in a series of steps from 500 to 1100℃C at reducing atmosphere, was investigated in optical absorption and XPS measurements. It is found that the implanted niobium in sapphire is in different local environments with different chemical states after the annealing. The changes in optical density (OD) from the bands, based on the well known F-type centers, show that the annealing behavior of the radiation damage may be divided into different stages due to different mechanisms.

  15. Solid State and Chemical Radiation Dosimetry in Medicine and Biology. Proceedings of a Symposium

    International Nuclear Information System (INIS)

    Proceedings of a Symposium organized by the IAEA and held in Vienna, 3-7 October 1966. The meeting was attended by 104 participants from 21 countries and three international organizations. Contents: Solid state dosimetry (17 papers); Chemical dosimetry (10 papers); Invited lectures (2 papers); General aspects and other methods of dosimetry (6 papers); Panel discussion on research and development needed in dosimetry. Each paper is in its original language (32 English, 2 French and 1 Spanish) and is preceded by an abstract in English and one in the original language, if this is not English. Discussions are in English. (author)

  16. Ensemble velocity of non-processive molecular motors with multiple chemical states

    CERN Document Server

    Vilfan, Andrej

    2014-01-01

    We study the ensemble velocity of non-processive motor proteins, described with multiple chemical states. In particular, we discuss the velocity as a function of ATP concentration. Even a simple model which neglects the strain-dependence of transition rates, reverse transition rates and nonlinearities in the elasticity can show interesting functional dependencies, which deviate significantly from the frequently assumed Michaelis-Menten form. We discuss how the oder of events in the duty cycle can be inferred from the measured dependence. The model also predicts the possibility of velocity reversal at a certain ATP concentration if the duty cycle contains several conformational changes of opposite directionalities.

  17. Recurrence quantification analysis of chimera states

    Science.gov (United States)

    Santos, M. S.; Szezech, J. D.; Batista, A. M.; Caldas, I. L.; Viana, R. L.; Lopes, S. R.

    2015-10-01

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse.

  18. Chemical state of mercury and selenium in sewage sludge ash based P-fertilizers.

    Science.gov (United States)

    Vogel, Christian; Krüger, Oliver; Herzel, Hannes; Amidani, Lucia; Adam, Christian

    2016-08-01

    Phosphorus-fertilizers from secondary resources such as sewage sludge ash (SSA) will become more important in the future as they could substitute conventional fertilizers based on the nonrenewable resource phosphate rock. Thermochemical approaches were developed which remove heavy metals from SSA prior to its fertilizer application on farmlands. We analyzed the chemical state of mercury and selenium in SSA before and after thermochemical treatment under different conditions for P-fertilizer production by X-ray absorption near edge structure (XANES) spectroscopy. In some incineration plants the mercury loaded carbon adsorber from off-gas cleaning was collected together with the SSA for waste disposal. SSAs from those plants contained mercury mainly bound to carbon/organic material. The other SSAs contained inorganic mercury compounds which are most probably stabilized in the SSA matrix and were thus not evaporated during incineration. During thermochemical treatment, carbon-bound mercury was removed quantitatively. In contrast, a certain immobile fraction of inorganic mercury compounds remained in thermochemically treated SSA, which were not clearly identified. HgSe might be one of the inorganic compounds, which is supported by results of Se K-edge XANES spectroscopy. Furthermore, the chemical state of selenium in the SSAs was very sensitive to the conditions of the thermochemical treatment. PMID:27060867

  19. 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...

  20. SOIL QUALITY ASSESSMENT BASED ON CHEMICAL, ENZYMATIC AND BACTERIOLOGICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Sofia-Paulina BALAURE

    2012-01-01

    Full Text Available This study highlights the problem of soil pollution as the result of human activities. Soil pollutans may be either chemicals or biological in nature. microbial enzymatic activities are often proposed as indicators of environmental stress. The soil samples were submitted by chemical, microbiological and enzymatic analyses. Chemical analyses were been made for determinating the heavy metals. Heavy metals from the forest soil were represented by Cu, Zn, Mn, Ni, Pb, Cd and Cr. To evaluate the concentration in heavy metals from the filtrate, we used a acetylene-nitrous oxide flame atomic absorption spectrophotometry. Potential dehydrogenase activity, the only indicator of the possible sources of pollution, excluded the presence of either chemical or biological pollution. The number of bacteria involved in the biogeochemical cycle of nitrogen in the analyzed soil indicated a high efficiency regarding the mineralization of the organic residues of plant and animal origin.

  1. Quantifying the chemical composition of soil organic carbon with solid-state 13C NMR

    Science.gov (United States)

    Baldock, J. A.; Sanderman, J.

    2011-12-01

    The vulnerability of soil organic carbon (SOC) to biological decomposition and mineralisation to CO2 is defined at least partially by its chemical composition. Highly aromatic charcoal-like SOC components are more stable to biological decomposition than other forms of carbon including cellulose. Solid-state 13C NMR has gained wide acceptance as a method capable of defining SOC chemical composition and mathematical fitting processes have been developed to estimate biochemical composition. Obtaining accurate estimates depends on an ability to quantitatively detect all carbon present in a sample. Often little attention has been paid to defining the proportion of organic carbon present in a soil that is observable in solid-state 13C NMR analyses of soil samples. However, if such data is to be used to inform carbon cycling studies, it is critical that quantitative assessments of SOC observability be undertaken. For example, it is now well established that a significant discrimination exists against the detection of the low proton content polyaromatic structures typical of charcoal using cross polarisation 13C NMR analyses. Such discrimination does not exist where direct polarisation analyses are completed. In this study, the chemical composition of SOC as defined by cross polarisation and direct polarisation13C NMR analyses will be compared for Australian soils collected from under a diverse range of agricultural managements and climatic conditions. Results indicate that where significant charcoal C contents exist, it is highly under-represented in the acquired CP spectra. For some soils, a discrimination against alkyl carbon was also evident. The ability to derive correction factors to compensate for such discriminations will be assessed and presented.

  2. Novel chemically cross-linked solid state electrolyte for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Yin Xiong; Tan Weiwei; Xiang Wangchun [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)] [Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Lin Yuan, E-mail: Linyuan@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Jingbo, E-mail: jbzhang@iccas.ac.c [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Xiao Xurui; Li Xueping; Zhou Xiaowen; Fang Shibi [Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-08-01

    Poly(vinylpyridine-co-ethylene glycol methyl ether methacrylate) (P(VP-co-MEOMA)) and {alpha},{omega}-diiodo poly(ethylene oxide-co-propylene oxide) (I[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub y}I) were synthesized and used as chemically cross-linked precursors of the electrolyte for dye-sensitized solar cells. Meanwhile, {alpha}-iodo poly(ethylene oxide-co-propylene oxide) methyl ether (CH{sub 3}O[(EO){sub 0.8}-co-(PO){sub 0.2}]{sub x}I) was synthesized and added into the electrolyte as an internal plasticizer. Novel polymer electrolyte resulting from chemically cross-linked precursors was obtained by the quaterisation at 90 {sup o}C for 30 min. The characteristics for this kind of electrolyte were investigated by means of ionic conductivity, thermogravimetric and photocurrent-voltage. The ambient ionic conductivity was significantly enhanced to 2.3 x 10{sup -4} S cm{sup -1} after introducing plasticizer, modified-ionic liquid. The weight loss of the solid state electrolyte at 200 {sup o}C was 1.8%, and its decomposition temperature was 287 {sup o}C. Solid state dye-sensitized solar cell based on chemically cross-linked electrolyte presented an overall conversion efficiency of 2.35% under AM1.5 irradiation (100 mW cm{sup -2}). The as-fabricated device maintained 88% of its initial performance at room temperature even without sealing for 30 days, showing a good stability.

  3. Chemical Analysis of Wastewater from Unconventional Drilling Operations

    OpenAIRE

    Jonathan B. Thacker; Doug D. Carlton; Zacariah L. Hildenbrand; Kadjo, Akinde F.; Schug, Kevin A.

    2015-01-01

    Trillions of liters of wastewater from oil and gas extraction are generated annually in the US. The contribution from unconventional drilling operations (UDO), such as hydraulic fracturing, to this volume will likely continue to increase in the foreseeable future. The chemical content of wastewater from UDO varies with region, operator, and elapsed time after production begins. Detailed chemical analyses may be used to determine its content, select appropriate treatment options, and identify ...

  4. Quasi-Chemical and Structural Analysis of Polarizable Anion Hydration

    OpenAIRE

    Rogers, David M.; Beck, Thomas L.

    2009-01-01

    Quasi-chemical theory is utilized to analyze the roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl$^-$, Br$^-$, and I$^-$. Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The quasi-chemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by...

  5. 40 CFR 761.292 - Chemical extraction and analysis of individual samples and composite samples.

    Science.gov (United States)

    2010-07-01

    ....61(a)(6) § 761.292 Chemical extraction and analysis of individual samples and composite samples. Use... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Chemical extraction and analysis of individual samples and composite samples. 761.292 Section 761.292 Protection of Environment...

  6. Use of thermogravimetry on rational analysis of clay minerals from state of Mato Grosso do Sul

    International Nuclear Information System (INIS)

    The rational analysis on clay minerals, normally uses as structural water, the mass loss by firing. The presence of organic materials, sulphur or others minerals, can cause an error on quantification of structural water. With the use of thermal gravimetric analysis, we can calculate, in a more precise way, the quantity of mass loss by dehydroxylation, without take into account the loss of mass from others process. We compared the rational chemical analysis on some clay minerals from state of Mato Grosso do Sul using burning loss and thermal gravimetric analysis. (author)

  7. Stochastic quasi-steady state approximations for asymptotic solutions of the chemical master equation

    Energy Technology Data Exchange (ETDEWEB)

    Alarcón, Tomás [Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona) (Spain); Departament de Matemàtiques, Universitat Atonòma de Barcelona, 08193 Bellaterra (Barcelona) (Spain)

    2014-05-14

    In this paper, we propose two methods to carry out the quasi-steady state approximation in stochastic models of enzyme catalytic regulation, based on WKB asymptotics of the chemical master equation or of the corresponding partial differential equation for the generating function. The first of the methods we propose involves the development of multiscale generalisation of a WKB approximation of the solution of the master equation, where the separation of time scales is made explicit which allows us to apply the quasi-steady state approximation in a straightforward manner. To the lowest order, the multi-scale WKB method provides a quasi-steady state, Gaussian approximation of the probability distribution. The second method is based on the Hamilton-Jacobi representation of the stochastic process where, as predicted by large deviation theory, the solution of the partial differential equation for the corresponding characteristic function is given in terms of an effective action functional. The optimal transition paths between two states are then given by those paths that maximise the effective action. Such paths are the solutions of the Hamilton equations for the Hamiltonian associated to the effective action functional. The quasi-steady state approximation is applied to the Hamilton equations thus providing an approximation to the optimal transition paths and the transition time between two states. Using this approximation we predict that, unlike the mean-field quasi-steady approximation result, the rate of enzyme catalysis depends explicitly on the initial number of enzyme molecules. The accuracy and validity of our approximated results as well as that of our predictions regarding the behaviour of the stochastic enzyme catalytic models are verified by direct simulation of the stochastic model using Gillespie stochastic simulation algorithm.

  8. Analysis of transition state theory for condensation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By statistically analyzing the condensation process and reconsidering the transition state theory for condensation and evaporation, we first presented a completed theoretical formula of the condensation coefficient. Namely, the unknown parameters contained within the transition state theoretical calculation of the condensation coefficient are determined. The condensation coefficients calculated from this formula agree well with those from molecular dynamics simulations. With this formula, the classical expression of the condensation flux developed from the gas kinetic theory can be used to predict the condensation flux.

  9. Refractometry and interferometry in chemical analysis; Refractometrie et interferometrie en analyse chimique

    Energy Technology Data Exchange (ETDEWEB)

    Veret, C. [Faculte des Sciences de Paris, 75 (France)

    2000-03-01

    In vacuum, an electromagnetic radiation is propagated at a constant velocity. But, when it has to pass through a physical medium, it is submitted to different interactions (for instance: absorption, diffusion, refraction, polarization, dispersion, fluorescence) which lead to a modification of its propagation. In the frequency ranges of the radiation for which the absorption is not very important, the modifications of the propagation velocity of a radiation can bring data on the nature and/or the physical conditions (pressure, temperature) of a medium, whatever its state be: gas, liquid or solid. Thus, the absolute refractive index of a medium in relation to vacuum is defined as the ratio c/v of the propagation velocity c of a monochromatic electromagnetic radiation in vacuum at its velocity v in this medium. The photonic refractometry (field of ultraviolet, visible and infrared radiations) is the set of the measure techniques of the refractive indexes having a role in chemical analysis. The refractometry measures can only be applied to media which are optically transparent. After having described these techniques, the author presents their uses in chemical analysis. (O.M.)

  10. Evaluating Chemical Persistence in a Multimedia Environment: ACART Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, D.H.; McKone, T.E.; Kastenberg, W.E.

    1999-02-01

    For the thousands of chemicals continuously released into the environment, it is desirable to make prospective assessments of those likely to be persistent. Persistent chemicals are difficult to remove if adverse health or ecological effects are later discovered. A tiered approach using a classification scheme and a multimedia model for determining persistence is presented. Using specific criteria for persistence, a classification tree is developed to classify a chemical as ''persistent'' or ''non-persistent'' based on the chemical properties. In this approach, the classification is derived from the results of a standardized unit world multimedia model. Thus, the classifications are more robust for multimedia pollutants than classifications using a single medium half-life. The method can be readily implemented and provides insight without requiring extensive and often unavailable data. This method can be used to classify chemicals when only a few properties are known and be used to direct further data collection. Case studies are presented to demonstrate the advantages of the approach.

  11. Load Characteristics Analysis of State Grid

    Institute of Scientific and Technical Information of China (English)

    Chen Wei; Zhou Feng; Han Xinyang; Shan Baoguo; Zhu Li

    2009-01-01

    @@ Introduction Analysis and forecast of load characteristics are important aspects in power market analysis and prediction.Correctly mastering grid load characteristics and its development trend is not only the vital basis for power planning,generation and operation,but also the important references for formulating the relevant policies.It is usually very hard to grasp the load characteristics of power grid.

  12. Chemical reactivity of graphene oxide towards amines elucidated by solid-state NMR

    Science.gov (United States)

    Vacchi, Isabella A.; Spinato, Cinzia; Raya, Jésus; Bianco, Alberto; Ménard-Moyon, Cécilia

    2016-07-01

    Graphene oxide (GO) is an attractive nanomaterial for many applications. Controlling the functionalization of GO is essential for the design of graphene-based conjugates with novel properties. But, the chemical composition of GO has not been fully elucidated yet. Due to the high reactivity of the oxygenated moieties, mainly epoxy, hydroxyl and carboxyl groups, several derivatization reactions may occur concomitantly. The reactivity of GO with amine derivatives has been exploited in the literature to design graphene-based conjugates, mainly through amidation. However, in this study we undoubtedly demonstrate using magic angle spinning (MAS) solid-state NMR that the reaction between GO and amine functions occurs via ring opening of the epoxides, and not by amidation. We also prove that there is a negligible amount of carboxylic acid groups in two GO samples obtained by a different synthesis process, hence eliminating the possibility of amidation reactions with amine derivatives. This work brings additional insights into the chemical reactivity of GO, which is fundamental to control its functionalization, and highlights the major role of MAS NMR spectroscopy for a comprehensive characterization of derivatized GO.Graphene oxide (GO) is an attractive nanomaterial for many applications. Controlling the functionalization of GO is essential for the design of graphene-based conjugates with novel properties. But, the chemical composition of GO has not been fully elucidated yet. Due to the high reactivity of the oxygenated moieties, mainly epoxy, hydroxyl and carboxyl groups, several derivatization reactions may occur concomitantly. The reactivity of GO with amine derivatives has been exploited in the literature to design graphene-based conjugates, mainly through amidation. However, in this study we undoubtedly demonstrate using magic angle spinning (MAS) solid-state NMR that the reaction between GO and amine functions occurs via ring opening of the epoxides, and not by

  13. 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.

  14. ANALYSIS OF SOLUBLE CHEMICAL TRANSFER BY RUNOFF WATER IN FIELD

    Institute of Scientific and Technical Information of China (English)

    TONG Ju-xiu; YANG Jin-zhong

    2008-01-01

    In order to determine the main factors influencing soluble chemical transfer and corresponding techniques for reducing fertilizer loss caused by runoff in irrigated fields, a physically based two-layer model was developed with incomplete mixing theory. Different forms of incomplete mixing parameters were introduced in the model, which was successfully verified with previous published experimental data. According to comparison, the chemicals loss of fertilizer is very sensitive to the runoff-related parameter while it is not sensitive to the infiltration-related parameter. The calculated results show that the chemicals in infiltration water play an important role in the early time of rainfall even with saturated soil, and it is mainly in the runoff flow in the late rainfall. Therefore, prevention of shallow subsurface drainage in the early rainfall is an effective way to reduce fertilizer loss, and the coverage on soil surface is another effective way.

  15. Chemical Water Quality Assessment in Selected Location in Jos, Plateau State, Nigeria

    Directory of Open Access Journals (Sweden)

    G.G. Jidauna

    2014-05-01

    Full Text Available The study examined well water quality (chemical in Jos metropolis which it collected a total of twenty water samples that were taken for laboratory analysis. The stratified systematic random method was used in the selection of sample area/location. A total of (10 out of the existing (20 wards were systematically selected, while in each of the wards, two wells with one each from higher and lower elevations were randomly selected in which water samples were collected. The samples collected were analyses at UNICEF (WATSAN Laboratory Bauchi. USEPA method of water analysis was used to test for the chemical parameters. Pearson product moment correlation co-efficient was used test for the relationship between high and low elevation in the sample elements, as well as mean and standard deviation. The results indicates that pH, E.C, TDS, Pb, As and Cyanide appears within NSDWQMPL, while NO2, Cl, F, Mn, Mg, Ca, Cu, Zn, CaCo3 and Cr marginally falls within acceptable standard for drinking water quality maximum permitted limit. Consequently, NO3, SO4, Fe and CaCo3 in some parts of Jos metropolis fall outside acceptable standard of NSDWQMPL. Moreover, pH, E.C, TDS, Pb, NO2, NO3, Cl, F, Mn, Cr, As, Cu, Zn, showed that there is no significant relationship within the individual elements in regards to elevation (high and low in the study area whereas, SO4, Fe, Mg, Ca, CaCo 3 and CaCo3 showed that there is significant relationship in elevation (high and low among the individual sample elements. The study concludes that well water quality through chemical assessment in Jos metropolis is not fit for drinking. It recommends sensitizations campaign on the importance of clean water, sanitation, enforcement of existing laws and more research be undertaken to cover for seasonal variation, more elements and sample size.

  16. 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.

  17. An introduction to state space time series analysis.

    OpenAIRE

    Commandeur, J.J.F. & Koopman, S.J.

    2007-01-01

    Providing a practical introduction to state space methods as applied to unobserved components time series models, also known as structural time series models, this book introduces time series analysis using state space methodology to readers who are neither familiar with time series analysis, nor with state space methods. The only background required in order to understand the material presented in the book is a basic knowledge of classical linear regression models, of which a brief review is...

  18. State-Recovery Analysis of Spritz

    DEFF Research Database (Denmark)

    Ankele, Ralph; Kölbl, Stefan; Rechberger, Christian

    2015-01-01

    , requiring only a short segment of keystream, with an approximated complexity of 21400, which is much faster than exhaustive search through all possible states, but is still far away from a practical attack. Furthermore, we introduce a second algorithm that uses a pattern in the keystream to reduce...

  19. Chemical Analysis: An Indispensable Means for Uncovering Severe Cases of Fraud with Cosmetics and Tattoo Inks.

    Science.gov (United States)

    Hohl, Christopher; Hauri, Urs

    2016-01-01

    Three cases of fraud with commodities containing illegal stealth compounds are presented, which were uncovered by the State Laboratory Basel-City, Switzerland. All three commodities, grapefruit seed extracts, a phytocosmetical skin cream, and tattoo inks, were produced abroad, had forged declarations of ingredients and, in the case of the extracts and the cream, were marketed with far-reaching health claims. While inspections will identify suspicious products and would be able to eliminate health claims to some extent, only chemical analysis can uncover the illegal agents used and give law enforcement bodies the necessary evidence to immediately clamp down on those brands, where the stealth agent presents a serious health hazard to consumers. PMID:27198815

  20. Determination of chemical pollutants in the atmosphere of the Valley of Toluca by neutron activation analysis

    International Nuclear Information System (INIS)

    The studies about the presence of contaminants in the atmosphere of diverse cities have been increased widely because to the problems that those cause to public health. Because of this in 1986 was made an Atmospheric Monitoring Program in the Valley of Toluca including the city of Toluca and Toluca- Lerma industrial corridor. That program consist of a preliminary net of sampling for the recollection of total suspended particles on glass-fiber filters, the sampling was performed two times a week in five different zones. To date have been analyzed some of these filters by atomic absorption in the Chemistry School of the Mexico's State University. In this work, is showed the establishment of chemical treatment technique and the results of quantitative analysis through neutron activation in filters of recent monitoring. (Author)

  1. Powerful chemical technique. [CSIR uses new x-ray diffractometer for structural chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    The CSIR's National Chemical Research Laboratory (NCRL) is now using one of the most powerful techniques available to determine the structure of molecules. It has recently acquired a Single Crystal X-ray Diffractometer. This powerful method provides the only means of determining the structure of certain compounds. NCRL scientists often carry out structure determinations to find out the relative or absolute stereochemistry of molecules. This is important when correlating physiological activity and structure, information which is necessary for synthesizing medicines with specific characteristics.

  2. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    International Nuclear Information System (INIS)

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conventional techniques have been achieved. This has resulted in minimum detection limits for transition metals of 8 x 107 atoms/cm2. SR-TXRF studies of the amount of metal contamination deposited on a silicon surface as a function of pH and oxygen content of the etching solutions have provided insights into the mechanisms of metal deposition from solutions containing trace amounts of metals ranging from parts per trillion to parts per billion. Furthermore, by using XANES to understand the chemical state of the metal atmos after deposition, it has been possible to develop chemical models for the deposition processes. Examples will be provided for copper deposition from ultra pure water and acidic solutions. (author)

  3. Chemical fingerprinting of whitewares from Nanwa site of the Chinese Erlitou state

    International Nuclear Information System (INIS)

    Whitewares are among the most significant finds from Erlitou, China's earliest state (c. 1900-1500 BC). They were primarily discovered in small numbers from elite tombs of a few sites, leading to the hypothesis that they were made at only a few places and then circulated as prestige items. Recent archaeological work indicates Nanwa may be a whiteware production site. To facilitate determining provenances, we compare the ICP-MS trace elements and TIMS Sr isotopes of Nanwa whitewares with those from Tang dynasty (618-907 AD) Gongxian kilns and Song dynasty (960-1279 AD) Ding kilns. Although all were made of white-firing kaolinic clays, each of the three groups shows a different chemical composition. Furthermore, samples from Nanwa are chemically consistent and restricted in a way analogous to those from Gongxian and Ding, implying that Nanwa whiteware was probably produced in situ. In addition, Gongxian and Ding samples define two separate linear arrays in their 87Rb/86Sr versus 87Sr/86Sr ratios, demonstrating that the clays for these samples are respectively related geochemically. Nanwa samples fall out of the linear arrays of both Gongxian and Ding, indicating that Nanwa whiteware clays were not derived from the same source rock as Gongxian clays, although the two sites are only some 25.5 km apart. In sum, beyond the general similarity of kaolinic clays used at Nanwa, Gongxian and Ding and the geographical proximity of those sites, finer distinctions of elemental and Sr isotopic contents indicate relatively unique chemical characteristics for each group. These traits provide valuable criteria to source traded ceramics of uncertain origins

  4. Chemical fingerprinting of whitewares from Nanwa site of the Chinese Erlitou state

    Energy Technology Data Exchange (ETDEWEB)

    Li Baoping [Centre for Microscopy and Microanalysis, University of Queensland, QLD 4072 (Australia)], E-mail: b.li@uq.edu.au; Liu Li [Archaeology Program, La Trobe University, Melbourne, VIC 3086 (Australia); Zhao Jianxin [Centre for Microscopy and Microanalysis, University of Queensland, QLD 4072 (Australia); Chen Xingcan [Institute of Archaeology, Chinese Academy of Social Sciences, Beijing 100710 (China); Feng Yuexing [Centre for Microscopy and Microanalysis, University of Queensland, QLD 4072 (Australia); Han Guohe; Zhu Junxiao [Department of Archaeology, Zhengzhou University, Zhengzhou 450052 (China)

    2008-06-15

    Whitewares are among the most significant finds from Erlitou, China's earliest state (c. 1900-1500 BC). They were primarily discovered in small numbers from elite tombs of a few sites, leading to the hypothesis that they were made at only a few places and then circulated as prestige items. Recent archaeological work indicates Nanwa may be a whiteware production site. To facilitate determining provenances, we compare the ICP-MS trace elements and TIMS Sr isotopes of Nanwa whitewares with those from Tang dynasty (618-907 AD) Gongxian kilns and Song dynasty (960-1279 AD) Ding kilns. Although all were made of white-firing kaolinic clays, each of the three groups shows a different chemical composition. Furthermore, samples from Nanwa are chemically consistent and restricted in a way analogous to those from Gongxian and Ding, implying that Nanwa whiteware was probably produced in situ. In addition, Gongxian and Ding samples define two separate linear arrays in their {sup 87}Rb/{sup 86}Sr versus {sup 87}Sr/{sup 86}Sr ratios, demonstrating that the clays for these samples are respectively related geochemically. Nanwa samples fall out of the linear arrays of both Gongxian and Ding, indicating that Nanwa whiteware clays were not derived from the same source rock as Gongxian clays, although the two sites are only some 25.5 km apart. In sum, beyond the general similarity of kaolinic clays used at Nanwa, Gongxian and Ding and the geographical proximity of those sites, finer distinctions of elemental and Sr isotopic contents indicate relatively unique chemical characteristics for each group. These traits provide valuable criteria to source traded ceramics of uncertain origins.

  5. 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...

  6. Analysis of chemical coal cleaning processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    Six chemical coal cleaning processes were examined. Conceptual designs and costs were prepared for these processes and coal preparation facilities, including physical cleaning and size reduction. Transportation of fine coal in agglomerated and unagglomerated forms was also discussed. Chemical cleaning processes were: Pittsburgh Energy Technology Center, Ledgemont, Ames Laboratory, Jet Propulsion Laboratory (two versions), and Guth Process (KVB). Three of the chemical cleaning processes are similar in concept: PETC, Ledgemont, and Ames. Each of these is based on the reaction of sulfur with pressurized oxygen, with the controlling factor being the partial pressure of oxygen in the reactor. All of the processes appear technically feasible. Economic feasibility is less certain. The recovery of process chemicals is vital to the JPL and Guth processes. All of the processes consume significant amounts of energy in the form of electric power and coal. Energy recovery and increased efficiency are potential areas for study in future more detailed designs. The Guth process (formally designed KVB) appears to be the simplest of the systems evaluated. All of the processes require future engineering to better determine methods for scaling laboratory designs/results to commercial-scale operations. A major area for future engineering is to resolve problems related to handling, feeding, and flow control of the fine and often hot coal.

  7. Portfolio Assessment on Chemical Reactor Analysis and Process Design Courses

    Science.gov (United States)

    Alha, Katariina

    2004-01-01

    Assessment determines what students regard as important: if a teacher wants to change students' learning, he/she should change the methods of assessment. This article describes the use of portfolio assessment on five courses dealing with chemical reactor and process design during the years 1999-2001. Although the use of portfolio was a new…

  8. Matching Element Symbols with State Abbreviations: A Fun Activity for Browsing the Periodic Table of Chemical Elements

    Science.gov (United States)

    Woelk, Klaus

    2009-01-01

    A classroom activity is presented in which students are challenged to find matches between the United States two-letter postal abbreviations for states and chemical element symbols. The activity aims to lessen negative apprehensions students might have when the periodic table of the elements with its more than 100 combinations of letters is first…

  9. Changes in chemical state and local structure of green rust by addition of copper sulphate ions

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)], E-mail: ssuzuki@tagen.tohoku.ac.jp; Shinoda, K. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Sato, M. [Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Fujimoto, S. [Osaka University, 1-1 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Yamashita, M. [University of Hyogo, 1-3-3, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo, 650-0044 (Japan); Konishi, H. [Japan Atomic Energy Agency, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Doi, T.; Kamimura, T. [Sumitomo Metal Industries Ltd. 1-10, Fuso-cho, Amagasaki, Hyogo, 660-0891 (Japan); Inoue, K.; Waseda, Y. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2008-06-15

    The X-ray absorption near edge structure (XANES), the extended X-ray absorption fine structure (EXAFS) and X-ray diffraction (XRD) measurements were used for characterising the effect of the addition of copper sulphate ions on the chemical state and local structure of hydrosulphate green rust (GR). Fe K edge XANES spectra showed that Fe(II) in GR was partially oxidised by the addition of the copper sulphate solution. Cu K edge XANES spectra showed that the copper sulphate ions in the GR suspension were reduced to zero charge copper. Radial structural functions indicated that the structure of GR comprised edge sharing of FeO{sub 6} octahedral units, which was changed by the oxidation of Fe(II). In addition, it was found that the GR was partially oxidised to {alpha}-FeOOH by the addition of copper ions.

  10. Multivariate Statistical Analysis of Phyllite Samples Based on Chemical (XRF) and Mineralogical Data by XRD

    OpenAIRE

    2012-01-01

    It is presented the results obtained of a multivariate statistical analysis concerning the chemical and phase composition, as a characterization purpose, carried out with 52 rock phyllite samples selected from the provinces of Almería and Granada (SE Spain). Chemical analysis was performed by X-ray fluorescence (XRF). Crystalline phase analysis was performed by X-ray powder diffraction (XRD) and the mineralogical composition was then deduced. Quantification of weight loss (100° an...

  11. Research on the chemical adsorption precursor state of CaCl2-NH3 for adsorption refrigeration

    Institute of Scientific and Technical Information of China (English)

    WANG; Liwei; WANG; Ruzhu; WU; Jingyi; WANG; Kai

    2005-01-01

    As a type of chemical adsorption working pair, the physical adsorption occurs first for CaCl2-NH3 because the effective reaction distance for van der Waals force is longer than that for chemical reaction force, and this physical adsorption state is named the precursor state of chemical adsorption. In order to get the different precursor states of CaCl2-NH3, the different distances between NH3 gas and Ca2+ are realized by the control of different phenomena of swelling and agglomeration in the process of adsorption. When the serious swelling exists while the agglomeration does not exist in the process of adsorption, experimental results show that the activated energy consumed by adsorption reaction increases for the reason of longer distance between Ca2+ and NH3, and at the same time the performance attenuation occurs in the repeated adsorption cycles. When the agglomeration occurs in the process of adsorption, the activated energy for the transition from precursor state to chemical adsorption decreases because the distance between NH3 gas and Ca2+ is shortened by the limited expansion space of adsorbent, and at the same time the performance attenuation does not occur. The adsorption refrigeration isobars are researched by the precursor state of chemical adsorption; results also show that the precursor state is a key factor for isobaric adsorption performance while the distribution of Ca2+ does not influence the permeation of NH3 gas in adsorbent.

  12. Mass spectrometry analysis of polychlorinated biphenyls: chemical ionization and selected ion chemical ionization using methane as a reagent gas

    OpenAIRE

    RAYMOND E. MARCH; MILA D. LAUSEVIC; TATJANA M. VASILJEVIC

    2000-01-01

    In the present paper a quadrupole ion trap mass spectrometer, coupled with a gas chromatograph, was used to compare the electron impact ionization (EI) and chemical ionization (Cl) technique, in terms of their selectivity in polychlorinated biphenyls (PCBs) quantitative analysis. The experiments were carried out with a modified Varian SATURN III quadrupole ion-storage mass spectrometer equipped with Varian waveform generator, coupled with a gas chromatograph with DB-5 capillary column. The di...

  13. Prediction of monomer reactivity in radical copolymerizations from transition state quantum chemical descriptors

    Directory of Open Access Journals (Sweden)

    Zhengde Tan

    2013-01-01

    Full Text Available In comparison with the Q-e scheme, the Revised Patterns Scheme: the U, V Version (the U-V scheme has greatly improved both its accessibility and its accuracy in interpreting and predicting the reactivity of a monomer in free-radical copolymerizations. Quantitative structure-activity relationship (QSAR models were developed to predict the reactivity parameters u and v of the U-V scheme, by applying genetic algorithm (GA and support vector machine (SVM techniques. Quantum chemical descriptors used for QSAR models were calculated from transition state species with structures C¹H3 - C²HR³• or •C¹H2 - C²H2R³ (formed from vinyl monomers C¹H²=C²HR³ + H•, using density functional theory (DFT, at the UB3LYP level of theory with 6-31G(d basis set. The optimum support vector regression (SVR model of the reactivity parameter u based on Gaussian radial basis function (RBF kernel (C = 10, ε = 10- 5 and γ = 1.0 produced root-mean-square (rms errors for the training, validation and prediction sets being 0.220, 0.326 and 0.345, respectively. The optimal SVR model for v with the RBF kernel (C = 20, ε = 10- 4 and γ = 1.2 produced rms errors for the training set of 0.123, the validation set of 0.206 and the prediction set of 0.238. The feasibility of applying the transition state quantum chemical descriptors to develop SVM models for reactivity parameters u and v in the U-V scheme has been demonstrated.

  14. Steady State Analysis of Towed Marine Cables

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; HUANG Guo-liang; DENG De-heng

    2008-01-01

    Efficient numerical schemes were presented for the steady state solutions of towed marine cables. For most of towed systems, the steady state problem can be resolved into two-point boundary-value problem, or initial value problem in some special cases where the initial values are available directly. A new technique was proposed and attempted to solve the two-point boundary-value problem rather than the conventional shooting method due to its algorithm complexity and low efficiency. First, the boundary conditions are transformed into a set of nonlinear governing equations about the initial values, then bisection method is employed to solve these nonlinear equations with the aid of 4th order Runge-Kutta method. In common sense, non-uniform (sheared) current is assumed, which varies in magnitude and direction with depth. The schemes are validated through the DE Zoysa's example, then several numerical examples are also presented to illustrate the numerical schemes.

  15. 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

  16. Effect of dielectric stoichiometry and interface chemical state on band alignment between tantalum oxide and platinum

    International Nuclear Information System (INIS)

    The tantalum oxide–platinum interface electronic properties determined by X-ray photoelectron spectroscopy are found to depend on the dielectric stoichiometry and platinum chemical state. We demonstrate the slow charging of the tantalum oxide in cases of Ta2O5/Pt and Ta2O5−y/Pt interfaces under the X-ray irradiation. This behavior is proposed to be related to the charge accumulation at oxygen vacancies induced traps. Based on the proposed methodology, we define the intrinsic conductive band offset (CBO) ∼1.3 eV (both for Ta2O5/Pt and Ta2O5−y/Pt) and CBO after the full saturation of the traps charging ∼0.5 eV, while the last one defines the energy position of charged traps below the bottom of conduction band. We demonstrate also the pining at the both Ta2O5/Pt and Ta2O5−y/Pt interfaces even in the “intrinsic” state, apparently induced by the presence of additional interfacial states. No shifts of Ta4f line and band alignment in over stoichiometric Ta2O5+x/Pt structure during X-ray irradiation, as well as the absence of pinning, resulting in increase of CBO up to 2.3 eV are found. This behavior is related to the PtO2 interfacing layer formation at Ta2O5+x/Pt, blocking the charging of the surface states and associated dipole formation

  17. Studies on surface chemical states of some metals and ceramics bombarded with energetic light-ions

    International Nuclear Information System (INIS)

    An electron spectroscopy was applied to the investigation of surface chemical state of some metals and ceramics bombarded with energetic light ions. Bombardments of keV-order hydrogen ions on Sc, Ti, V, Y, Zr and Nb induced the XPS core-line chemical shifts to higher binding-energies by 0.2 - 1.4 eV, the appearence of new photopeaks at 3.0 - 5.0 eV below the Fermi level. Although the peak energies are lower by 1 - 3 eV than those calculated for MeH2 (Me = metal) by molecular-orbital theory, the peaks are assigned to the metal-H bonds. The chemical shifts induced by bombarding hydrogen-ions were also observed in the X-ray-induced Auger electron spectra (XAES) For Y, Zr and Nb. The hydride layers produced by the ion-implantation are more stable at high temperature than those obtained by thermal synthesis, because of the surface damages which prevent thermal diffusion of hydrogen. In the case of hydrogen-ion bombarded SiC, carbon enriched layer was observed in the near surface region, while the surfaces of Si3N4 and SiO2 became silicon-rich after the bombardments. On the other hand, the bombardments of H2+, D2+ and He+-ions on TiC, TiN and TiO2 made their surfaces titanium-rich. At high fluences, the X/Ti (X = C, N, O) become constant. The energy dependences of the steady state values of the C/Ti ratios have maximum at 2 - 4 keV/atom of incident ion, while those of the N/Ti and O/Ti ratios decreased with the increase in the ion energies. Incident-energy dependences of the Ti+/X+ ratios determined by SIMS substantiate that the sputtering is responsible for the surface compositional change of the binary compounds. The surface of TiO2 was easily reduced to Ti2O3 by the H2+ and D2+, or to TiO by the He+ and Ar+-ion bombardments. The difference in the reduced species is correlated with the thermodynamical parameters of the corresponding reduction reactions. (J.P.N.)

  18. Summary Analysis [United States Water Resources Council].

    Science.gov (United States)

    Roose, John B.; Cobb, Gary D.

    This report contains a summary and analysis of public response to the Water Resources Council proposed principles and standards and its accompanying draft environmental impact statement for planning the use of water and related land resources as well as planning and evaluating water and related land resources programs and projects. Both written…

  19. Chemical state of Ag in Conducting Bridge Random Access Memory cells: a depth resolved X-ray Absorption Spectroscopy investigation.

    Science.gov (United States)

    d'Acapito, F.; Souchier, E.; Noe, P.; Blaise, P.; Bernard, M.; Jousseaume, V.

    2016-05-01

    Conducting Bridge Random Access Memories (CBRAM) are a promising substitute for FLASH technology but problems with limited retention of the low resistance ON state still hamper their massive deployment. Depth resolved X-ray Absorption Spectroscopy has been used to describe the chemical state of the atoms of the active electrode (in this case Ag) and to reveal the role of Sb as stabilizer of the metallic state.

  20. Modeling and analysis of uranium isotope enrichment by chemical exchange

    International Nuclear Information System (INIS)

    A theoretical study of uranium isotopes separation by chemical exchange, starting with an accurate mathematical model, is presented. The experimental data used in this study were obtained by reverse break-through operation and the numerical algorithm, developed for simulation in a previous study, was adapted to be suitable for this kind of processes. The model parameters were identified from experimental data and simulations were carried out for different experimental conditions. (author)

  1. Chemical non-equilibrium flow analysis of H2 fueled scramjet nozzle

    OpenAIRE

    Yue Huang; Peiyong Wang; Yang Dou; Fei Xing

    2015-01-01

    A numerical analysis of the chemical non-equilibrium phenomena in a scramjet nozzle has been performed using CHEMKIN software. Different operating conditions of the Hyshot scramjet nozzle were simulated and analyzed. Three chemical status, frozen flow, equilibrium flow, and non-equilibrium flow, were tested and compared to demonstrate the chemical reaction effect on nozzle flow field. The real non-equilibrium flow simulation result is between those of the two limiting cases: frozen flow and e...

  2. The Matthew Effect in Environmental Science Publication: A Bibliometric Analysis of Chemical Substances in Journal Articles

    OpenAIRE

    Grandjean Philippe; Eriksen Mette L; Ellegaard Ole; Wallin Johan A

    2011-01-01

    Abstract Background While environmental research addresses scientific questions of possible societal relevance, it is unclear to what degree research focuses on environmental chemicals in need of documentation for risk assessment purposes. Methods In a bibliometric analysis, we used SciFinder to extract Chemical Abstract Service (CAS) numbers for chemicals addressed by publications in the 78 major environmental science journals during 2000-2009. The Web of Science was used to conduct title se...

  3. Chemical Analysis of Emu Feather Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    V.Chandra sekhar

    2015-07-01

    Full Text Available A composite is usually made up of at least two materials out of which one is binding material called as matrix and other is a reinforcement material known as fiber. For the past ten years research is going on to explore possible composites with natural fiber like plant fibers and animal fibers. The important characteristics of composites are their strength, hardness light in weight. It is also necessary to study about the resistance of the composites for deferent chemicals. In the present work, composites prepared with epoxy (Araldite LY-556 as resin and „emu‟ bird feathers as fiber have been tested for chemical resistance. The composites were prepared by varying fiber loading (P of „emu‟ feathers ranging from 1 to 5 and length (L of feather fibers from 1 to 5 cm. The composites thus prepared were subjected to various chemicals (Acids, Alkalis, solvents etc.. Observations were plotted and studied. The results reveal that there will be weight gain for the composite samples after three days, when treated with Hydrochloric acid, Sodium carbonate, Acetic acid, Sodium hydroxide, Nitric acid and Ammonium hydroxide. Weight loss was observed for all the samples including pure epoxy when treated with Benzene, Carbon tetra chloride and Toluene.

  4. Tattoo inks: legislation, pigments, metals and chemical analysis.

    Science.gov (United States)

    Prior, Gerald

    2015-01-01

    Legal limits for chemical substances require that they are linked to clearly defined analytical methods. Present limits for certain chemicals in tattoo and permanent make-up inks do not mention analytical methods for the detection of metals, polycyclic aromatic hydrocarbons or forbidden colourants. There is, therefore, no established method for the determination of the quantities of these chemicals in tattoo and permanent make-up inks. Failing to provide an appropriate method may lead to unqualified and questionable results which often cause legal disputes that are ultimately resolved by a judge with regard to the method that should have been applied. Analytical methods are tuned to exactly what is to be found and what causes the health problems. They are extremely specific. Irrespective of which is the correct method for detecting metals in tattoo inks, the focus should be on the actual amounts of ink in the skin. CTL® has conducted experiments to determine these amounts and these experiments are crucial for toxicological evaluations and for setting legal limits. When setting legal limits, it is essential to also incorporate factors such as daily consumption, total uptake and frequency of use. A tattoo lasts for several decades; therefore, the limits that have been established for heavy metals used in drinking water or soap are not relevant. Drinking water is consumed on a daily basis and soap is used several times per week, while tattooing only occurs once. PMID:25833637

  5. Performance analysis of Isopropanol–Acetone–Hydrogen chemical heat pump

    International Nuclear Information System (INIS)

    Highlights: ► The increase of temperature of endothermic reaction reduces performance of heat pump. ► The better the performance is, the larger the number of trays. ► COP focuses on the quantity of recovered heat. ► Exergy efficiency focuses on the quantity and quality of recovered heat. - Abstract: The performance of an Isopropanol–Acetone–Hydrogen (IAH) chemical heat pump system is investigated in terms of enthalpy efficiency (COP) and exergy efficiency, in which the exothermic and endothermic reactions take place in the gas phase. The increase of reflux ratio, temperature of endothermic reaction and temperature of exothermic reaction reduces the performance of the heat pump when the other operating parameters remain unchanged. However, the performance of the IAH chemical heat pump improves with the increase of the ratio of molar quantity of hydrogen to that of acetone in the entry of exothermic reactor and the number of heat transfer units of regenerator. Generally, a better performance of the chemical heat pump corresponds to a larger number of trays in the distillation column. The performance of the system can be improved significantly after multi-parameter optimization design. The coefficient of performance (COP) pays more attention to the heat released from the exothermic reactor, while the exergy efficiency takes into consideration of both heat released from the exothermic reactor and temperature of exothermic reaction.

  6. 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. PMID:24274311

  7. Development of international standards for surface analysis by ISO technical committee 201 on surface chemical analysis

    International Nuclear Information System (INIS)

    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

  8. Los Alamos National Laboratory Center for direct chemical analysis of materials

    International Nuclear Information System (INIS)

    The Center for Direct Chemical Analysis at Los Alamos National Laboratory is undertaking a major effort to develop, improve, and implement direct analysis techniques for radionuclide, organic, and inorganic constituents. The Center consists of a multidisciplinary team of researchers who possess expertise in the quantitative and qualitative characterization of solid materials using a variety of analytical technologies. Materials include soils and sludges, building materials, foods, chemicals, and atmospheric gases. Direct chemical analysis techniques measure the analytes directly in the solid material with minimal sample pretreatment, whereas conventional techniques, such as atomic absorption and emission spectrochemistry, require that the solid materials be rendered in aqueous solution using concentrated acids prior to measurement. Direct chemical analysis completely bypasses the digestion process, thereby increasing the sample throughout and saving both time and money. Direct chemical analysis is unique in that it alone can conduct certain specialized but highly useful types of analysis, such as depth-profiling and the chemical structural characterization of surfaces. In addition, some direct analytical techniques eliminate the sampling step and permit rapid analysis of samples at the point of origin. Direct analysis in situ would further reduce costs and potential hazards related to sample collection and transport to the analytical laboratory

  9. 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,…

  10. Neutron activation analysis for chemical characterization of Brazilian oxo-biodegradable plastics

    International Nuclear Information System (INIS)

    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)

  11. Identification of environmentally relevant chemicals in bibliographic databases: a comparative analysis

    DEFF Research Database (Denmark)

    Ellegaard, Ole; Wallin, Johan Albert

    2013-01-01

    Valid and reliable information on the use and effects of chemicals is a key factor in the industry and not least within many regulatory agencies. Identification data from lists of substances sometimes leads to incomplete bibliographic analysis in the major chemical databases. The present study...

  12. Analysis of solids remaining following chemical cleaning in tank 6F

    International Nuclear Information System (INIS)

    Following chemical cleaning, a solid sample was collected and submitted to Savannah River National Laboratory (SRNL) for analysis. SRNL analyzed this sample by X-ray Diffraction (XRD) and scanning electron microscopy (SEM) to determine the composition of the solids remaining in Tank 6F and to assess the effectiveness of the chemical cleaning process.

  13. Forecasting global developments in the basic chemical industry for environmental policy analysis

    NARCIS (Netherlands)

    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 t

  14. Assessment of chemical exchange in tryptophan–albumin solution through 19F multicomponent transverse relaxation dispersion analysis

    International Nuclear Information System (INIS)

    A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T2 relaxation into Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion experiments to probe chemical exchange in a multicompartmental system. The proposed procedure was validated through analysis of 19F T2 relaxation data of 6-fluoro-DL-tryptophan in a two-compartment solution with and without bovine serum albumin. Given the regularized NNLS analysis of a T2 relaxation curve acquired, for example, at the CPMG frequency υCPMG = 125, the nature of two distinct peaks in the associated T2 distribution spectrum indicated 6-fluoro-DL-tryptophan either retaining the free state, with geometric mean */multiplicative standard deviation (MSD) = 1851.2 ms */1.51, or undergoing free/albumin-bound interconversion, with geometric mean */MSD = 236.8 ms */1.54, in the two-compartment system. Quantities of the individual tryptophan species were accurately reflected by the associated T2 peak areas, with an interconversion state-to-free state ratio of 0.45 ± 0.11. Furthermore, the CPMG relaxation dispersion analysis estimated the exchange rate between the free and albumin-bound states in this fluorinated tryptophan analog and the corresponding dissociation constant of the fluorinated tryptophan–albumin complex in the chemical-exchanging, two-compartment system

  15. Assessment of chemical exchange in tryptophan–albumin solution through {sup 19}F multicomponent transverse relaxation dispersion analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Ping-Chang, E-mail: pingchang.lin@howard.edu [Howard University, Department of Radiology, College of Medicine (United States)

    2015-06-15

    A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T{sub 2} relaxation into Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion experiments to probe chemical exchange in a multicompartmental system. The proposed procedure was validated through analysis of {sup 19}F T{sub 2} relaxation data of 6-fluoro-DL-tryptophan in a two-compartment solution with and without bovine serum albumin. Given the regularized NNLS analysis of a T{sub 2} relaxation curve acquired, for example, at the CPMG frequency υ{sub CPMG} = 125, the nature of two distinct peaks in the associated T{sub 2} distribution spectrum indicated 6-fluoro-DL-tryptophan either retaining the free state, with geometric mean */multiplicative standard deviation (MSD) = 1851.2 ms */1.51, or undergoing free/albumin-bound interconversion, with geometric mean */MSD = 236.8 ms */1.54, in the two-compartment system. Quantities of the individual tryptophan species were accurately reflected by the associated T{sub 2} peak areas, with an interconversion state-to-free state ratio of 0.45 ± 0.11. Furthermore, the CPMG relaxation dispersion analysis estimated the exchange rate between the free and albumin-bound states in this fluorinated tryptophan analog and the corresponding dissociation constant of the fluorinated tryptophan–albumin complex in the chemical-exchanging, two-compartment system.

  16. Practical use of chemical shift databases for protein solid-state NMR: 2D chemical shift maps and amino-acid assignment with secondary-structure information

    International Nuclear Information System (INIS)

    We introduce a Python-based program that utilizes the large database of 13C and 15N chemical shifts in the Biological Magnetic Resonance Bank to rapidly predict the amino acid type and secondary structure from correlated chemical shifts. The program, called PACSYlite Unified Query (PLUQ), is designed to help assign peaks obtained from 2D 13C–13C, 15N–13C, or 3D 15N–13C–13C magic-angle-spinning correlation spectra. We show secondary-structure specific 2D 13C–13C correlation maps of all twenty amino acids, constructed from a chemical shift database of 262,209 residues. The maps reveal interesting conformation-dependent chemical shift distributions and facilitate searching of correlation peaks during amino-acid type assignment. Based on these correlations, PLUQ outputs the most likely amino acid types and the associated secondary structures from inputs of experimental chemical shifts. We test the assignment accuracy using four high-quality protein structures. Based on only the Cα and Cβ chemical shifts, the highest-ranked PLUQ assignments were 40–60 % correct in both the amino-acid type and the secondary structure. For three input chemical shifts (CO–Cα–Cβ or N–Cα–Cβ), the first-ranked assignments were correct for 60 % of the residues, while within the top three predictions, the correct assignments were found for 80 % of the residues. PLUQ and the chemical shift maps are expected to be useful at the first stage of sequential assignment, for combination with automated sequential assignment programs, and for highly disordered proteins for which secondary structure analysis is the main goal of structure determination.

  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. PMID:19418043

  18. Electron spectroscopies for simultaneous chemical and electrical analysis

    International Nuclear Information System (INIS)

    Electrons are used as spectroscopic probes to determine elemental composition and chemistry, and are also useful as probes of the electrical properties of devices and materials. In this paper, four examples with incident and emitted electrons were used to evaluate the electrical and chemical properties of samples. These examples were the electrical conductivity of an Ag-epoxy composite, the electric field in an avalanche photodiode near breakdown, the mechanism of conductivity of semi-insulating polycrystalline films, and the charge at an oxide/semiconductor interface for high-k applications. This kind of work is very much in the spirit of the work done by Prof. Sefik Suzer.

  19. 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...

  20. 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....

  1. LSENS, a general chemical kinetics and sensitivity analysis code for homogeneous gas-phase reactions. 2: Code description and usage

    Science.gov (United States)

    Radhakrishnan, Krishnan; Bittker, David A.

    1994-01-01

    LSENS, the Lewis General Chemical Kinetics Analysis Code, has been developed for solving complex, homogeneous, gas-phase chemical kinetics problems and contains sensitivity analysis for a variety of problems, including nonisothermal situations. This report is part 2 of a series of three reference publications that describe LSENS, provide a detailed guide to its usage, and present many example problems. Part 2 describes the code, how to modify it, and its usage, including preparation of the problem data file required to execute LSENS. Code usage is illustrated by several example problems, which further explain preparation of the problem data file and show how to obtain desired accuracy in the computed results. LSENS is a flexible, convenient, accurate, and efficient solver for chemical reaction problems such as static system; steady, one-dimensional, inviscid flow; reaction behind incident shock wave, including boundary layer correction; and perfectly stirred (highly backmixed) reactor. In addition, the chemical equilibrium state can be computed for the following assigned states: temperature and pressure, enthalpy and pressure, temperature and volume, and internal energy and volume. For static problems the code computes the sensitivity coefficients of the dependent variables and their temporal derivatives with respect to the initial values of the dependent variables and/or the three rate coefficient parameters of the chemical reactions. Part 1 (NASA RP-1328) derives the governing equations describes the numerical solution procedures for the types of problems that can be solved by lSENS. Part 3 (NASA RP-1330) explains the kinetics and kinetics-plus-sensitivity-analysis problems supplied with LSENS and presents sample results.

  2. Practical chemical analysis of Pt and Pd based heterogeneous catalysts with hard X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Highlights: •Hard X-ray photoelectron spectroscopy (HAXPES) enables interface analysis of catalyst. •HAXPES enables overall analysis of porous film of Pt-doped CeO2 and related catalyst. •HAXPES enables analysis of trace elements for Pd and Pt3Ni nanoparticle catalysts. -- Abstract: Interfacial properties including configuration, porosity, chemical states, and atomic diffusion greatly affect the performance of supported heterogeneous catalysts. Hard X-ray photoelectron spectroscopy (HAXPES) can be used to analyze the interfaces of heterogeneous catalysts because of its large information depth of more than 20 nm. We use HAXPES to examine Pt-doped CeO2 and related thin film catalysts evaporated on Si, carbon, and carbon nanotube substrates, because Pt-doped CeO2 has great potential as a noble metal-based heterogeneous catalyst for fuel cells. The HAXPES measurements clarify that the dopant material, substrate material, and surface pretreatment of substrate are important parameters that affect the interfacial properties of Pt-doped CeO2 and related thin film catalysts. Another advantage of HAXPES measurement of heterogeneous catalysts is that it can be used for chemical analysis of trace elements by detecting photoelectrons from deep core levels, which have large photoionization cross-sections in the hard X-ray region. We use HAXPES for chemical analysis of trace elements in Pd nanoparticle catalysts immobilized on sulfur-terminated substrates and Pt3Ni nanoparticle catalysts enveloped by dendrimer molecules

  3. Chemical risk evaluation, importance of the risk analysis framework uses: Latin America development restrictions

    International Nuclear Information System (INIS)

    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

  4. Literature survey of chemical analysis by thermal neutron induced capture gamma ray spectrometry

    International Nuclear Information System (INIS)

    A brief discussion of the principles and techniques of chemical analysis by neutron capture gamma radiation is presented, and the widely scattered literature is collected into a single table arranged by element measured

  5. Chemical analysis and sampling techniques for geothermal fluids and gases at the Fenton Hill Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, P.E.; Counce, D.; Grigsby, C.O.; Goff, F.; Shevenell, L.

    1987-06-01

    A general description of methods, techniques, and apparatus used for the sampling, chemical analysis, and data reporting of geothermal gases and fluids is given. Step-by-step descriptions of the procedures are included in the appendixes.

  6. Chemical composition, mixing state, size and morphology of Ice nucleating particles at the Jungfraujoch research station, Switzerland

    Science.gov (United States)

    Ebert, Martin; Worringen, Annette; Kandler, Konrad; Weinbruch, Stephan; Schenk, Ludwig; Mertes, Stephan; Schmidt, Susan; Schneider, Johannes; Frank, Fabian; Nilius, Björn; Danielczok, Anja; Bingemer, Heinz

    2014-05-01

    An intense field campaign from the Ice Nuclei Research Unit (INUIT) was performed in January and February of 2013 at the High-Alpine Research Station Jungfraujoch (3580 m a.s.l., Switzerland). Main goal was the assessment of microphysical and chemical properties of free-tropospheric ice-nucelating particles. The ice-nucleating particles were discriminated from the total aerosol with the 'Fast Ice Nucleation CHamber' (FINCH; University Frankfurt) and the 'Ice-Selective Inlet' (ISI, Paul Scherer Institute) followed by a pumped counter-stream virtual impactor. The separated ice-nucleating particles were then collected with a nozzle-type impactor. With the 'FRankfurt Ice nuclei Deposition freezinG Experiment' (FRIDGE), aerosol particles are sampled on a silicon wafer, which is than exposed to ice-activating conditions in a static diffusion chamber. The locations of the growing ice crystals are recorded for later analysis. Finally, with the ICE Counter-stream Virtual Impactor (ICE-CVI) atmospheric ice crystals are separated from the total aerosol and their water content is evaporated to retain the ice residual particles, which are then collected also by impactor sampling. All samples were analyzed in a high-resolution scanning electron microscope. By this method, for each particle its size, morphology, mixing-state and chemical composition is obtained. In total approximately 1700 ice nucleating particles were analyzed. Based on their chemical composition, the particles were classified into seven groups: silicates, metal oxides, Ca-rich particles, (aged) sea-salt, soot, sulphates and carbonaceous matter. Sea-salt is considered as artifact and is not regarded as ice nuclei here. The most frequent ice nucleating particles/ice residuals at the Jungfraujoch station are silicates > carbonaceous particles > metal oxides. Calcium-rich particles and soot play a minor role. Similar results are obtained by quasi-parallel measurements with an online single particle laser ablation

  7. Toxic hazard and chemical analysis of leachates from furfurylated wood.

    Science.gov (United States)

    Pilgård, Annica; Treu, Andreas; van Zeeland, Albert N T; Gosselink, Richard J A; Westin, Mats

    2010-09-01

    The furfurylation process is an extensively investigated wood modification process. Furfuryl alcohol molecules penetrate into the wood cell wall and polymerize in situ. This results in a permanent swelling of the wood cell walls. It is unclear whether or not chemical bonds exist between the furfuryl alcohol polymer and the wood. In the present study, five different wood species were used, both hardwoods and softwoods. They were treated with three different furfurylation procedures and leached according to three different leaching methods. The present study shows that, in general, the leachates from furfurylated wood have low toxicity. It also shows that the choice of leaching method is decisive for the outcome of the toxicity results. Earlier studies have shown that leachates from wood treated with furfuryl alcohol prepolymers have higher toxicity to Vibrio fischeri than leachates from wood treated with furfuryl alcohol monomers. This is probably attributable to differences in leaching of chemical compounds. The present study shows that this difference in the toxicity most likely cannot be attributed to maleic acid, furan, furfural, furfuryl alcohol, or 2-furoic acid. However, the difference might be caused by the two substances 5-hydroxymethylfurfural and 2,5-furandimethanol. The present study found no difference in the amount of leached furfuryl alcohol between leachates from furfurylated softwood and furfurylated hardwood species. Earlier studies have indicated differences in grafting of furfuryl alcohol to lignin. However, nothing was found in the present study that could support this. The leachates of furfurylated wood still need to be PMID:20821648

  8. THE INTERACTIVE DECISION COMMITTEE FOR CHEMICAL TOXICITY ANALYSIS.

    Science.gov (United States)

    Kang, Chaeryon; Zhu, Hao; Wright, Fred A; Zou, Fei; Kosorok, Michael R

    2012-01-01

    We introduce the Interactive Decision Committee method for classification when high-dimensional feature variables are grouped into feature categories. The proposed method uses the interactive relationships among feature categories to build base classifiers which are combined using decision committees. A two-stage or a single-stage 5-fold cross-validation technique is utilized to decide the total number of base classifiers to be combined. The proposed procedure is useful for classifying biochemicals on the basis of toxicity activity, where the feature space consists of chemical descriptors and the responses are binary indicators of toxicity activity. Each descriptor belongs to at least one descriptor category. The support vector machine, the random forests, and the tree-based AdaBoost algorithms are utilized as classifier inducers. Forward selection is used to select the best combinations of the base classifiers given the number of base classifiers. Simulation studies demonstrate that the proposed method outperforms a single large, unaggregated classifier in the presence of interactive feature category information. We applied the proposed method to two toxicity data sets associated with chemical compounds. For these data sets, the proposed method improved classification performance for the majority of outcomes compared to a single large, unaggregated classifier. PMID:24415822

  9. Chemical and non-chemical s tressors affecting childhood obesity: a state-of-the-science-review

    Science.gov (United States)

    Childhood obesity has tripled in the last three decades and now affects 17% of children in the United States (US). In 2010, the percentage of obese children in the US was nearly 18% for both 6-11 and 12-19 years of age. Recent evidence in the literature suggests that exposure to ...

  10. Analysis of equation of state for nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Uma D., E-mail: uma_sharma18@yahoo.co [Department of Physics, G.B. Pant University of Agriculture and Technology, Pantnagar 263145 (India); Kumar, Munish, E-mail: munish_dixit@yahoo.co [Department of Physics, G.B. Pant University of Agriculture and Technology, Pantnagar 263145 (India)

    2011-02-15

    An equation of state (EOS) recently proposed for nanomaterials is discussed critically. Different possible forms of the EOS are discussed with their correlations. We have considered 20 nanomaterials for this purpose, viz. CdSe, Rb{sub 3}C{sub 60}, carbon nanotube, {gamma}-Fe{sub 2}O{sub 3}, {epsilon}-Fe (hexagonal iron), MgO, {gamma}-Al{sub 2}O{sub 3} (67 nm), {alpha}-Fe{sub 2}O{sub 3}, {alpha}-Fe (filled nanotube), TiO{sub 2} (anatase), 3C-SiC (30 nm), TiO{sub 2} (rutile phase), Zr{sub 0.1}Ti{sub 0.9}O{sub 2}, {gamma}-Si{sub 3}N{sub 4}, Ni-filled MWCNT, Fe-filled MWCNT, CeO{sub 2} (cubic fluorite phase and orthorhombic phase), germanium (49 nm), GaN (wurtzite phase) and SnO{sub 2} (rutile phase) (14 nm). It is found that the change in the form of EOS does not improve the results. This demonstrates the validity of the EOS proposed for nanomaterials. The EOS is also used to study the effect of temperature on compression of Ni (20 nm). It is found that there is small shift in isotherm due to increase in the temperature. The results have been found to present a good agreement with the available experimental data.

  11. Chemical analysis of steel (citations from the NTIS Data Base). Report for 1964-Apr 80

    Energy Technology Data Exchange (ETDEWEB)

    Cavagnaro, D.M.

    1980-05-01

    Information is cited on chemical analysis of boron, nitrogen, hydrogen, sulfur, silicon, carbon, oxygen, aluminum, rare earths, and other trace elements in steel. In addition, research on the determination of major elements, including iron, is covered. New techniques and refinement of older techniques, including x-ray fluorescence, spectroscopy, chromatography, activation analysis, and wet chemical methods are also included. (This updated bibliography contains 240 abstracts, 14 of which are new entries to the previous edition.)

  12. Applications of a versatile technique for trace analysis: atmospheric pressure negative chemical ionization.

    OpenAIRE

    Thomson, B A; Davidson, W R; Lovett, A M

    1980-01-01

    The ability to use ambient air as a carrier and reagent gas in an atmospheric pressure chemical ionization source allows instantaneous air analysis to be combined with hypersensitivity toward a wide variety of compounds. The TAGA (Trace Atmospheric Gas Analyser) is an instrument which is designed to use both positive and negative atmospheric pressure chemical ionization (APCI) for trace gas analysis; this paper describes several applications of negative APCI which demonstrates that the techni...

  13. ANALYSIS OF THE CHEMICAL COMPOSITION AND MORPHOLOGICAL STRUCTURE OF BANANA PSEUDO-STEM

    OpenAIRE

    Kun Li; Shiyu Fu; Huaiyu Zhan; Yao Zhan; Lucian A. Lucia

    2010-01-01

    An analysis of the chemical composition and anatomical structure of banana pseudo-stem was carried out using Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM). The chemical analysis indicated there is a high holocellulose content and low lignin content in banana pseudo-stem compared with some other non-wood fiber resources. These results demonstrate that the banana pseudo-stem has potential value for pulping. In addition, we report for th...

  14. Chemical or Biological Terrorist Attacks: An Analysis of the Preparedness of Hospitals for Managing Victims Affected by Chemical or Biological Weapons of Mass Destruction

    Directory of Open Access Journals (Sweden)

    Russell L. Bennett

    2006-03-01

    and analysis. Six hypotheses were tested. Using a questionnaire survey, the availability of functional preparedness plans, specific preparedness education/training, decontamination facilities, surge capacity, pharmaceutical supplies, and laboratory diagnostic capabilities of hospitals were examined. The findings revealed that a majority (89.2% of hospitals in the State of Mississippi have documented preparedness plans, provided specific preparedness education/training (89.2%, have dedicated facilities for decontamination (75.7%, and pharmaceutical plans and supplies (56.8% for the treatment of victims in the event of a disaster involving chemical or biological WMD. However, over half (59.5% of the hospitals could not increase surge capacity (supplies, equipment, staff, patient beds, etc. and lack appropriate laboratory diagnostic services (91.9% capable of analyzing and identifying WMD. In general, hospitals in the State of Mississippi, like a number of hospitals throughout the United States, are still not adequately prepared to manage victims of terrorist attacks involving chemical or biological WMD which consequently may result in the loss of hundreds or even thousands of lives. Therefore, hospitals continue to require substantial resources at the local, State, and national levels in order to be “truly” prepared.

  15. Evolution analysis of the states of the EZ model

    International Nuclear Information System (INIS)

    Based on suitable choice of states, this paper studies the stability of the equilibrium state of the EZ model by regarding the evolution of the EZ model as a Markov chain and by showing that the Markov chain is ergodic. The Markov analysis is applied to the EZ model with small number of agents, the exact equilibrium state for N = 5 and numerical results for N = 18 are obtained. (cross-disciplinary physics and related areas of science and technology)

  16. States' Potential Enrollment of Adult Students: A Stochastic Frontier Analysis

    Science.gov (United States)

    Titus, Marvin A.; Pusser, Brian

    2011-01-01

    This study shows that financial aspects of state higher education policies, particularly tuition, have an impact on the level of enrollment of adult undergraduates within a state. This study also demonstrates how stochastic frontier analysis (SFA) can be utilized to examine the "potential" maximum enrollment of adult learners in postsecondary…

  17. Behaviour State Analysis in Rett Syndrome: Continuous Data Reliability Measurement

    Science.gov (United States)

    Woodyatt, Gail; Marinac, Julie; Darnell, Ross; Sigafoos, Jeff; Halle, James

    2004-01-01

    Awareness of optimal behaviour states of children with profound intellectual disability has been reported in the literature as a potentially useful tool for planning intervention within this population. Some arguments have been raised, however, which question the reliability and validity of previously published work on behaviour state analysis.…

  18. Statistically optimal analysis of state-discretized trajectory data from multiple thermodynamic states

    CERN Document Server

    Wu, Hao; Rosta, Edina; Noé, Frank

    2014-01-01

    We propose a discrete transition-based reweighting analysis method (dTRAM) for analyzing configuration-space-discretized simulation trajectories produced at different thermodynamic states (temperatures, Hamiltonians, etc.) dTRAM provides maximum-likelihood estimates of stationary quantities (probabilities, free energies, expectation values) at any thermodynamic state. In contrast to the weighted histogram analysis method (WHAM), dTRAM does not require data to be sampled from global equilibrium, and can thus produce superior estimates for enhanced sampling data such as parallel/simulated tempering, replica exchange, umbrella sampling, or metadynamics. In addition, dTRAM provides optimal estimates of Markov state models (MSMs) from the discretized state-space trajectories at all thermodynamic states. Under suitable conditions, these MSMs can be used to calculate kinetic quantities (e.g. rates, timescales). In the limit of a single thermodynamic state, dTRAM estimates a maximum likelihood reversible MSM, while i...

  19. Mortality among flavour and fragrance chemical plant workers in the United States.

    OpenAIRE

    Thomas, T L

    1987-01-01

    Vital status on 1 January 1981 was determined for a cohort of 1412 white men employed in a flavour and fragrance chemical plant between 1945 and 1965 in order to investigate the risks from fatal diseases among men exposed to multiple chemicals in the manufacture of fragrances, flavours, aroma chemicals, and other organic substances. Cause specific standardised mortality ratios (SMRs) were calculated for the entire study population and for several subsets by likelihood of exposure to chemicals...

  20. Two-step complete polarization logic Bell-state analysis.

    Science.gov (United States)

    Sheng, Yu-Bo; Zhou, Lan

    2015-01-01

    The Bell state plays a significant role in the fundamental tests of quantum mechanics, such as the nonlocality of the quantum world. The Bell-state analysis is of vice importance in quantum communication. Existing Bell-state analysis protocols usually focus on the Bell-state encoding in the physical qubit directly. In this paper, we will describe an alternative approach to realize the near complete logic Bell-state analysis for the polarized concatenated Greenberger-Horne-Zeilinger (C-GHZ) state with two logic qubits. We show that the logic Bell-state can be distinguished in two steps with the help of the parity-check measurement (PCM) constructed by the cross-Kerr nonlinearity. This approach can be also used to distinguish arbitrary C-GHZ state with N logic qubits. As both the recent theoretical and experiment work showed that the C-GHZ state has its robust feature in practical noisy environment, this protocol may be useful in future long-distance quantum communication based on the logic-qubit entanglement. PMID:26307327

  1. State budget periodicity: An analysis of the determinants and the effect on state spending

    OpenAIRE

    Paula S. Kearns

    1994-01-01

    Much of the public budgeting literature focuses on the institutional rules of budgeting and how those rules affect process and outcomes. This study focuses on a particularly rudimentary rule of budgeting: the length of the budget period. State budgets are dictated (constitutionally or statutorily) to recur over one-or two-year intervals. Statistical analysis of the determinants of state budget periodicity shows that the more states spend, ceteris paribus, the more likely they are to budget an...

  2. Is Income Growth in the United States Pro-Poor? A State-Level Analysis

    OpenAIRE

    Edinaldo Tebaldi; Jongsung Kim

    2015-01-01

    This study uses the Current Population Survey and a decomposition method proposed by Datt and Ravallion to assess the impacts of income growth and income distribution on poverty across states in the United States. It finds that between 1992 and 2011 growth of income, rather than changes in income distribution, was the major source of poverty reduction across US states. The empirical analysis also shows that there is asymmetrical impact on poverty — via both income distribution and income grow...

  3. CHEMKIN-III: A FORTRAN chemical kinetics package for the analysis of gas-phase chemical and plasma kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Kee, R.J.; Rupley, F.M.; Meeks, E.; Miller, J.A.

    1996-05-01

    This document is the user`s manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular FORTRAN subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little or no changes to CHEMKIN implementation for systems in thermal equilibrium, where all species share the same gas temperature. CHEMKIN-III now has the capability to handle weakly ionized plasma chemistry, especially for application related to advanced semiconductor processing.

  4. FINITE ELEMENT METHOD AND ANALYSIS FOR CHEMICAL-FLOODING SIMULATION

    Institute of Scientific and Technical Information of China (English)

    YUAN Yirang

    2000-01-01

    This article discusses the enhanced oil recovery numerical simulation of the chemical-flooding (such as surfactants, alcohol, polymers) composed of three-dimensional multicomponent, multiphase and incompressible mixed fluids. The mathematical model can be described as a coupled system of nonlinear partial differential equations with initialboundary value problems. From the actual conditions such as the effect of cross interference and the three-dimensional characteristic of large-scale science-engineering computation, this article puts forward a kind of characteristic finite element fractional step schemes and obtain the optimal order error estimates in L2 norm. Thus we have thoroughly solved the well-known theoretical problem proposed by a famous scientist, R. E. Ewing.

  5. Nanoscale chemical analysis and imaging of solid oxide cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Bowen, Jacob R.; Kuhn, Luise Theil;

    2008-01-01

    The performance of solid oxide cells (SOCs) is highly dependent on triple phase boundaries (TPBs). Therefore, detailed TPB characterization is crucial for their further development. We demonstrate that it is possible to prepare a similar to 50 nm thick transmission electron microscopy (TEM) lamella...... of the interface between the dense ceramic electrolyte and the porous metallic/ceramic hydrogen electrode of an SOC using focused ion beam milling. We show combined TEM/scanning TEM/energy-dispersive spectroscopy investigations of the nanostructure at the TPBs in a high-performance SOC. The chemical...... composition of nanoscale impurity phases at the TPBs has been obtained with a few nanometers lateral resolution. (c) 2008 The Electrochemical Society....

  6. Chemical weapons detection by fast neutron activation analysis techniques

    International Nuclear Information System (INIS)

    A neutron diagnostic experimental apparatus has been tested for nondestructive verification of sealed munitions. Designed to potentially satisfy a significant number of van-mobile requirements, this equipment is based on an easy to use industrial sealed tube neutron generator that interrogates the munitions of interest with 14 MeV neutrons. Gamma ray spectra are detected with a high purity germanium detector, especially shielded from neutrons and gamma ray background. A mobile shell holder has been used. Possible configurations allow the detection, in continuous or in pulsed modes, of gamma rays from neutron inelastic scattering, from thermal neutron capture, and from fast or thermal neutron activation. Tests on full scale sealed munitions with chemical simulants show that those with chlorine (old generation materials) are detectable in a few minutes, and those including phosphorus (new generation materials) in nearly the same time. (orig.)

  7. Analysis of Chemical Composition of Atmospheric Aerosols Above a South East Asian Rainforest

    Science.gov (United States)

    Robinson, N. H.; Allan, J. D.; Williams, P. I.; Hamilton, J. F.; Chen, Q.; Martin, S. T.; Coe, H.; McFiggans, G. B.

    2008-12-01

    The tropics emit a huge amount of volatile organic compounds (VOCs) into the Earth's atmosphere. The processes by which these gases are oxidised to form secondary organic aerosol (SOA) are not well understood or quantified. Insight into the origins and properties of these particles can be gained by analysis of their composition. Intensive field measurements were carried out as part of the Oxidant and Particle Photochemical Processes (OP3) and the Aerosol Coupling in the Earth System (ACES) projects in the rainforest in Malaysian Borneo. This is the first campaign of its type in a South East Asian rainforest. We present detailed organic aerosol composition measurements made using an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) at Bukit Atur, a Global Atmosphere Watch site located in the Danum Valley Conservation Area. This is a state-of-the-art field deployable instrument that can provide real time composition, mass loading and aerodynamic particle sizing information. In addition, the mass spectral resolution is sufficient to perform an analysis of the elemental composition of the organic species present. Other tools such as positive matrix factorisation (PMF) have been used to help assess the relative source contributions to the organic aerosol. The aerosol's chemical origins have been further investigated by comparing these spectra to chamber experiments, mass spectral libraries and data from comparable locations in other locations. These data are also being analysed in conjunction with high complexity offline techniques applied to samples collected using filters and a Particle-Into-Liquid Sampler (PILS). Methods used include liquid chromatography and comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry. These techniques provide a more detailed chemical characterisation of the SOA and water soluble organic carbon, allowing direct links back to gas phase precursors.

  8. Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds

    Science.gov (United States)

    Ebert, M.; Worringen, A.; Benker, N.; Mertes, S.; Weingartner, E.; Weinbruch, S.

    2011-03-01

    During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In terms of number lead-bearing particles are enriched by a factor of approximately 25, complex internal mixtures with silicates or metal oxides as major components by a factor of 11, and mixtures of secondary aerosol and carbonaceous material (C-O-S particles) by a factor of 2. Other particle groups (sulfates, sea salt, Ca-rich particles, external silicates) observed in the ice-residual samples cannot be assigned unambiguously as IN. Between 9 and 24% of all IR are Pb-bearing particles. Pb was found as major component in around 10% of these particles (PbO, PbCl2). In the other particles, Pb was found as some 100 nm sized agglomerates consisting of 3-8 nm sized primary particles (PbS, elemental Pb). C-O-S particles are present in the IR at an abundance of 17-27%. The soot component within these particles is strongly aged. Complex internal mixtures occur in the IR at an abundance of 9-15%. Most IN identified at the Jungfraujoch station are internal mixtures containing anthropogenic components (either as main or minor constituent), and it is concluded that admixture of the anthropogenic component is responsible for the increased IN efficiency within mixed phase clouds. The mixing state appears to be a key parameter for the ice nucleation behaviour that cannot be predicted from the sole knowledge of the main component of an individual particle.

  9. THE BACTERIOLOGICAL AND PHYSICO-CHEMICAL STUDIES ON OLUMIRIN WATERFALL ERIN- IJESHA, OSUN STATE, NIGERIA

    Directory of Open Access Journals (Sweden)

    Oluwakemi Akindolapo

    2011-10-01

    Full Text Available The potability and qualities of Olumirin waterfall, Erin-Ijesa were investigated by determining the total bacteria and coliform count with antibiotic susceptibility of the isolated bacteria and physico-chemical qualities of the water samples. Total bacteria and coliform enumeration were determined using pour plating and multiple tube techniques, the antibiotic susceptibility were carried out using disc diffusion method, while physico-chemical and mineral studies were also carried out using standard methods. The mean total viable count of the water samples ranged 14.8 x 102 CFU.ml-1 - 21.3 x 103 CFU.ml-1 while the coliform count ranged 13 -175 MPN/100ml. The identified bacteria isolates and their percentage distribution were E.coli (43.1%, Klebsiella spp (20.7%, Proteus spp (12.1%, Salmonella spp (6.99%, Pseudomonas spp (5.17%, Shigella spp (6.9%, and Enterococcus spp (5.17 %. Antibiotic resistance shown by bacteria isolates were exhibited as follow; Nalixidic acid (31%, Ampicilin (76%, Cotrimoxazole (60%, Gentamicin (19%, Nitrofurantoin (24%, Colitin (48%, Streptomycin (34% and tetracycline (52%. 82.8% of the isolate exhibited multiple antibiotic resistance. The physico-chemical analysis also revealed the presence of some mineral elements in the water samples. The mineral value of the water samples include; magnesium (84.8 - 93.4 mg.L-1, phosphate (12.6 - 17.1 mg.L-1, sodium (47.8 - 87.6 mg.L-1, potassium (76.6 - 104.5 mg.L-1, chloride (59.0 - 90.2 mg.L-1, zinc (0.75 - 1.82 mg.L-1, lead (0.12 - 0.33 mg.L-1, iron (0.52 - 0.60 mg.L-1, copper (0.12 - 0.27 mg.L-1 while nickel and arsenic were not detected in any of the water samples. Comparing the experimental results with the international water standard for natural water, the waterfall is not fit for consumption or for any domestic purpose unless being treated. Also, problems that may arise from the resistance bacteria strains can be tackled while the new antibiotics can also be developed.

  10. Generalized molybdenum oxide surface chemical state XPS determination via informed amorphous sample model

    Energy Technology Data Exchange (ETDEWEB)

    Baltrusaitis, Jonas, E-mail: job314@lehigh.edu [Department of Chemical Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 (United States); PhotoCatalytic Synthesis group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede (Netherlands); Mendoza-Sanchez, Beatriz [CRANN, Chemistry School, Trinity College Dublin, Dublin (Ireland); Fernandez, Vincent [Institut des Matériaux Jean Rouxel, 2 rue de la Houssinière, BP 32229, F-44322 Nantes Cedex 3 (France); Veenstra, Rick [PhotoCatalytic Synthesis group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede (Netherlands); Dukstiene, Nijole [Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu pl. 19, LT-50254 Kaunas (Lithuania); Roberts, Adam [Kratos Analytical Ltd, Trafford Wharf Road, Wharfside, Manchester, M17 1GP (United Kingdom); Fairley, Neal [Casa Software Ltd, Bay House, 5 Grosvenor Terrace, Teignmouth, Devon TQ14 8NE (United Kingdom)

    2015-01-30

    Highlights: • We analyzed and modeled spectral envelopes of complex molybdenum oxides. • Molybdenum oxide films of varying valence and crystallinity were synthesized. • MoO{sub 3} and MoO{sub 2} line shapes from experimental data were created. • Informed amorphous sample model (IASM) developed. • Amorphous molybdenum oxide XPS envelopes were interpreted. - Abstract: Accurate elemental oxidation state determination for the outer surface of a complex material is of crucial importance in many science and engineering disciplines, including chemistry, fundamental and applied surface science, catalysis, semiconductors and many others. X-ray photoelectron spectroscopy (XPS) is the primary tool used for this purpose. The spectral data obtained, however, is often very complex and can be subject to incorrect interpretation. Unlike traditional XPS spectra fitting procedures using purely synthetic spectral components, here we develop and present an XPS data processing method based on vector analysis that allows creating XPS spectral components by incorporating key information, obtained experimentally. XPS spectral data, obtained from series of molybdenum oxide samples with varying oxidation states and degree of crystallinity, were processed using this method and the corresponding oxidation states present, as well as their relative distribution was elucidated. It was shown that monitoring the evolution of the chemistry and crystal structure of a molybdenum oxide sample due to an invasive X-ray probe could be used to infer solutions to complex spectral envelopes.

  11. Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension

    Science.gov (United States)

    Greene, Samuel M.; Shan, Xiao; Clary, David C.

    2016-06-01

    Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods.

  12. Stochastic theory of nonequilibrium steady states. Part II: Applications in chemical biophysics

    International Nuclear Information System (INIS)

    The mathematical theory of nonequilibrium steady state (NESS) has a natural application in open biochemical systems which have sustained source(s) and sink(s) in terms of a difference in their chemical potentials. After a brief introduction in Section , in Part II of this review, we present the widely studied biochemical enzyme kinetics, the workhorse of biochemical dynamic modeling, in terms of the theory of NESS (Section ). We then show that several phenomena in enzyme kinetics, including a newly discovered activation–inhibition switching (Section ) and the well-known non-Michaelis–Menten-cooperativity (Section ) and kinetic proofreading (Section ), are all consequences of the NESS of driven biochemical systems with associated cycle fluxes. Section is focused on nonlinear and nonequilibrium systems of biochemical reactions. We use the phosphorylation–dephosphorylation cycle (PdPC), one of the most important biochemical signaling networks, as an example (Section ). It starts with a brief introduction of the Delbrück–Gillespie process approach to mesoscopic biochemical kinetics (Sections ). We shall discuss the zeroth-order ultrasensitivity of PdPC in terms of a new concept — the temporal cooperativity (Sections ), as well as PdPC with feedback which leads to biochemical nonlinear bistability (Section ). Also, both are nonequilibrium phenomena. PdPC with a nonlinear feedback is kinetically isomorphic to a self-regulating gene expression network, hence the theory of NESS discussed here could have wide applications to many other biochemical systems.

  13. Rate constants of chemical reactions from semiclassical transition state theory in full and one dimension.

    Science.gov (United States)

    Greene, Samuel M; Shan, Xiao; Clary, David C

    2016-06-28

    Semiclassical Transition State Theory (SCTST), a method for calculating rate constants of chemical reactions, offers gains in computational efficiency relative to more accurate quantum scattering methods. In full-dimensional (FD) SCTST, reaction probabilities are calculated from third and fourth potential derivatives along all vibrational degrees of freedom. However, the computational cost of FD SCTST scales unfavorably with system size, which prohibits its application to larger systems. In this study, the accuracy and efficiency of 1-D SCTST, in which only third and fourth derivatives along the reaction mode are used, are investigated in comparison to those of FD SCTST. Potential derivatives are obtained from numerical ab initio Hessian matrix calculations at the MP2/cc-pVTZ level of theory, and Richardson extrapolation is applied to improve the accuracy of these derivatives. Reaction barriers are calculated at the CCSD(T)/cc-pVTZ level. Results from FD SCTST agree with results from previous theoretical and experimental studies when Richardson extrapolation is applied. Results from our implementation of 1-D SCTST, which uses only 4 single-point MP2/cc-pVTZ energy calculations in addition to those for conventional TST, agree with FD results to within a factor of 5 at 250 K. This degree of agreement and the efficiency of the 1-D method suggest its potential as a means of approximating rate constants for systems too large for existing quantum scattering methods. PMID:27369506

  14. Chemical Bonding States of TiC Films before and after Hydrogen Ion Irradiation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    TiC films deposited by rf magnetron sputtering followed by Ar+ ion bombardment were irradiated with a hydrogen ion beam. X-ray photoelectron spectroscopy (XPS) was used for characterization of the chemical bonding states of C and Ti elements of the TiC films before and after hydrogen ion irradiation, in order to understand the effect of hydrogen ion irradiation on the films and to study the mechanism of hydrogen resistance of TiC films. Conclusions can be drawn that ion bombardment at moderate energy can cause preferential physical sputtering of carbon atoms from the surface of low atomic number (Z) material. This means that ion beam bombardment leads to the formation of a non-stoichiometric composition of TiC on the surface.TiC films prepared by ion beam mixing have the more excellent characteristic of hydrogen resistance. One important cause, in addition to TiC itself, is that there are many vacant sites in TiC created by ion beam mixing.These defects can easily trap hydrogen and effectively enhance the effect of hydrogen resistance.

  15. Linear analysis near a steady-state of biochemical networks: control analysis, correlation metrics and circuit theory

    Directory of Open Access Journals (Sweden)

    Qian Hong

    2008-05-01

    Full Text Available Abstract Background: Several approaches, including metabolic control analysis (MCA, flux balance analysis (FBA, correlation metric construction (CMC, and biochemical circuit theory (BCT, have been developed for the quantitative analysis of complex biochemical networks. Here, we present a comprehensive theory of linear analysis for nonequilibrium steady-state (NESS biochemical reaction networks that unites these disparate approaches in a common mathematical framework and thermodynamic basis. Results: In this theory a number of relationships between key matrices are introduced: the matrix A obtained in the standard, linear-dynamic-stability analysis of the steady-state can be decomposed as A = SRT where R and S are directly related to the elasticity-coefficient matrix for the fluxes and chemical potentials in MCA, respectively; the control-coefficients for the fluxes and chemical potentials can be written in terms of RT BS and ST BS respectively where matrix B is the inverse of A; the matrix S is precisely the stoichiometric matrix in FBA; and the matrix eAt plays a central role in CMC. Conclusion: One key finding that emerges from this analysis is that the well-known summation theorems in MCA take different forms depending on whether metabolic steady-state is maintained by flux injection or concentration clamping. We demonstrate that if rate-limiting steps exist in a biochemical pathway, they are the steps with smallest biochemical conductances and largest flux control-coefficients. We hypothesize that biochemical networks for cellular signaling have a different strategy for minimizing energy waste and being efficient than do biochemical networks for biosynthesis. We also discuss the intimate relationship between MCA and biochemical systems analysis (BSA.

  16. Neutron activation analysis for assessing chemical composition of dry dog foods

    International Nuclear Information System (INIS)

    Brazil holds the second largest population of domestic dogs in the world, with 33 million dogs, only behind the United States. The annual consumption of dog food in the country is 1.75 million tons, corresponding to the World's sixth in trade turnover. Dog food is supposed to be a complete and balanced diet, formulated with high quality ingredients. All nutrients and minerals required for an adequate nutrition of dogs are added to the formulation to ensure longevity and welfare. In this context, the present study aimed at assessing the chemical composition of dry dog foods commercialized in Brazil. Thirty-four samples were acquired in the local market of Piracicaba and analyzed by instrumental neutron activation analysis (INAA) to determine the elements As, Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sb, Sc, Se, U, and Zn. In general, the concentrations of Ca, Fe, K, Na, and Zn complied with the values required by the Association of American Feed Control Officials (AAFCO). To evaluate the safety of dog food commercialized in Brazil, further investigation is necessary to better understand the presence of toxic elements found in this study, i.e. Sb and U. INAA was useful for the screening analysis of different types and brands of dry dog foods for the determination of both essential and toxic elements. (author)

  17. Synthesis and analysis in studies of chemical evolution

    Science.gov (United States)

    Ponnamperuma, C.; Hobish, M. K.; Kobayashi, K.; Hua, L. L.; Senaratne, N.

    1986-01-01

    Studies of the various processes that may have given rise to life on the Earth have demonstrated the appropriateness of an approach that makes use of analysis and synthesis. Analysis of extraterrestrial samples in the form of meteorites has demonstrated the presence of several precursors of biomolecules, most notably a full suite of nucleic acid bases and nucleotides of biological significance. These species were determined after exhaustive extraction of the sample and subsequent analysis using HPLC, GC, MS, and GC-MS. Procedural blanks indicate that these molecules are likely not the result of contamination during the extraction and analysis process. Similar species were found as products of spark discharge experiments in atmospheres thought to mimic primitive Earth conditions. These results indicate that the basic chemistry underlying these syntheses is common, and that life may not be unique to the Earth. Studies underway in the laboratory make use of proton nuclear magnetic resonance spectroscopy as a probe to assess associations between selected amino acids and any of several nucleotides comprising their genetic code and genetic anticode sequences. These studies demonstrate a clear selectivity by the anticode sequences, thus confirming the hydrophobicity studies performed by Lacey et al. These studies further support the contention that life is likely a natural result of the physics and chemistry of the universe.

  18. Biological Sampling and Analysis in Sinclair and Dyes Inlets, Washington: Chemical Analyses for 2007 Puget Sound Biota Study

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M.; Suslick, Carolynn R.; Johnston, Robert K.

    2008-10-09

    Evaluating spatial and temporal trends in contaminant residues in Puget Sound fish and macroinvertebrates are the objectives of the Puget Sound Ambient Monitoring Program (PSAMP). In a cooperative effort between the ENVironmental inVESTment group (ENVVEST) and Washington State Department of Fish and Wildlife, additional biota samples were collected during the 2007 PSAMP biota survey and analyzed for chemical residues and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Approximately three specimens of each species collected from Sinclair Inlet, Georgia Basin, and reference locations in Puget Sound were selected for whole body chemical analysis. The muscle tissue of specimens selected for chemical analyses were also analyzed for δ13C and δ15N to provide information on relative trophic level and food sources. This data report summarizes the chemical residues for the 2007 PSAMP fish and macro-invertebrate samples. In addition, six Spiny Dogfish (Squalus acanthias) samples were necropsied to evaluate chemical residue of various parts of the fish (digestive tract, liver, embryo, muscle tissue), as well as, a weight proportional whole body composite (WBWC). Whole organisms were homogenized and analyzed for silver, arsenic, cadmium, chromium, copper, nickel, lead, zinc, mercury, 19 polychlorinated biphenyl (PCB) congeners, PCB homologues, percent moisture, percent lipids, δ13C, and δ15N.

  19. State-selected chemical reaction dynamics at the S matrix level - Final-state specificities of near-threshold processes at low and high energies

    Science.gov (United States)

    Chatfield, David C.; Truhlar, Donald G.; Schwenke, David W.

    1992-01-01

    State-to-state reaction probabilities are found to be highly final-state specific at state-selected threshold energies for the reactions O + H2 yield OH + H and H + H2 yield H2 + H. The study includes initial rotational states with quantum numbers 0-15, and the specificity is especially dramatic for the more highly rotationally excited reactants. The analysis is based on accurate quantum mechanical reactive scattering calculations. Final-state specificity is shown in general to increase with the rotational quantum number of the reactant diatom, and the trends are confirmed for both zero and nonzero values of the total angular momentum.

  20. Chemical analysis applied to the radiation sterilization of solid ketoprofen

    Science.gov (United States)

    Colak, S.; Maquille, A.; Tilquin, B.

    2006-01-01

    The aim of this work is to investigate the feasibility of radiation sterilization of ketoprofen from a chemical point of view. Although irradiated ketoprofen has already been studied in the literature [Katusin-Razem et al., Radiat. Phys. Chem. 73 111-116 (2005)], new results, on the basis of electron spin resonance (ESR) measurements and the use of hyphenated techniques (GC-MS and LC-MS), are obtained. The ESR spectra of irradiated ketoprofen consists of four unresolved resonance peaks and the mean G-value of ketoprofen is found to be 4 +/- 0.9 nmoles/J, which is very small. HPLC-UV analyses indicate that no significant loss of ketoprofen is detected after irradiation. LC-MS-MS analyses show that the structures of the non-volatile final products are similar to ketoprofen. Benzaldehyde is detected in the irradiated samples after dynamic-extraction GC-MS. The analyses show that ketoprofen is radioresistant and therefore might be radiosterilized.

  1. Sampling and chemical analysis of urban street runoff

    International Nuclear Information System (INIS)

    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.)

  2. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred P M

    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.

  3. Virus and Bacterial Cell Chemical Analysis by NanoSIMS

    Energy Technology Data Exchange (ETDEWEB)

    Weber, P; Holt, J

    2008-07-28

    In past work for the Department of Homeland Security, the LLNL NanoSIMS team has succeeded in extracting quantitative elemental composition at sub-micron resolution from bacterial spores using nanometer-scale secondary ion mass spectrometry (NanoSIMS). The purpose of this task is to test our NanoSIMS capabilities on viruses and bacterial cells. This initial work has proven successful. We imaged Tobacco Mosaic Virus (TMV) and Bacillus anthracis Sterne cells using scanning electron microscopy (SEM) and then analyzed those samples by NanoSIMS. We were able resolve individual viral particles ({approx}18 nm by 300 nm) in the SEM and extract correlated elemental composition in the NanoSIMS. The phosphorous/carbon ratio observed in TMV is comparable to that seen in bacterial spores (0.033), as was the chlorine/carbon ratio (0.11). TMV elemental composition is consistent from spot to spot, and TMV is readily distinguished from debris by NanoSIMS analysis. Bacterial cells were readily identified in the SEM and relocated in the NanoSIMS for elemental analysis. The Ba Sterne cells were observed to have a measurably lower phosphorous/carbon ratio (0.005), as compared to the spores produced in the same run (0.02). The chlorine/carbon ratio was approximately 2.5X larger in the cells (0.2) versus the spores (0.08), while the fluorine/carbon ratio was approximately 10X lower in the cells (0.008) than the spores (0.08). Silicon/carbon ratios for both cells and spores encompassed a comparable range. The initial data in this study suggest that high resolution analysis is useful because it allows the target agent to be analyzed separate from particulates and other debris. High resolution analysis would also be useful for trace sample analysis. The next step in this work is to determine the potential utility of elemental signatures in these kinds of samples. We recommend bulk analyses of media and agent samples to determine the range of media compositions in use, and to determine how

  4. Archaeological and chemical analysis of Tell el Yahudiyeh ware

    International Nuclear Information System (INIS)

    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

  5. 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. PMID:12224422

  6. Evidence for excited-state intramolecular proton transfer in 4-chlorosalicylic acid from combined experimental and computational studies: Quantum chemical treatment of the intramolecular hydrogen bonding interaction

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Bijan Kumar [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India); Guchhait, Nikhil, E-mail: nikhil.guchhait@rediffmail.com [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Calcutta 700009 (India)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Experimental and computational studies on the photophysics of 4-chlorosalicylic acid. Black-Right-Pointing-Pointer Spectroscopically established ESIPT reaction substantiated by theoretical calculation. Black-Right-Pointing-Pointer Quantum chemical treatment of IMHB unveils strength, nature and directional nature. Black-Right-Pointing-Pointer Superiority of quantum chemical treatment of H-bond over geometric criteria. Black-Right-Pointing-Pointer Role of H-bond as a modulator of aromaticity. -- Abstract: The photophysical study of a pharmaceutically important chlorine substituted derivative of salicylic acid viz., 4-chlorosalicylic acid (4ClSA) has been carried out by steady-state absorption, emission and time-resolved emission spectroscopy. A large Stokes shifted emission band with negligible solvent polarity dependence marks the spectroscopic signature of excited-state intramolecular proton transfer (ESIPT) reaction in 4ClSA. Theoretical calculation by ab initio and Density Functional Theory methods yields results consistent with experimental findings. Theoretical potential energy surfaces predict the occurrence of proton transfer in S{sub 1}-state. Geometrical and energetic criteria, Atoms-In-Molecule topological parameters, Natural Bond Orbital population analysis have been exploited to evaluate the intramolecular hydrogen bond (IMHB) interaction and to explore its directional nature. The inter-correlation between aromaticity and resonance assisted H-bond is also discussed in this context. Our results unveil that the quantum chemical treatment is a more accurate tool to assess hydrogen bonding interaction in comparison to geometrical criteria.

  7. Wet chemical analysis for the semiconductor industry—a total view

    Science.gov (United States)

    Balazs, Marjorie K.

    1998-11-01

    The analysis of liquids to obtain information about semiconductor materials is known in the industry as "wet chemistry" and has been used since the beginning of the production of IC's. However, the analytical procedures never gained any significant attention until the mid 70's when the absolute measurement of phosphorus in PSG films by wet chemical analysis was incorporated by several industrial labs as the standard method of analysis. Today, over 120 different procedures are used to gain specific information about incoming and processed materials used in the industry. These procedures cover ultra pure water, chemicals, thin films, and wafer cleanliness. Furthermore, they are used to evaluate the cleanliness of reactors, cleanrooms, and components of all kinds that are used in cleanrooms, wet benches and reactors. This paper will cover a total look at the applications of wet chemical processes and the usefulness of the data obtained from these analytical techniques. The paper will cover not only those tests that one would expect to be done by wet processes such as the analysis of metals in chemicals, but will also cover many unusual applications of wet chemical analysis such as their usefulness in evaluating products from a variety of reactors. Included in this part of the presentation will be a unique application to determine ion implantation contaminants and recent advances for analyzing 300mm wafers without breaking them and the analysis of contamination metals in copper thin films. Actual data will be provided for each of the analytical techniques presented.

  8. Analysis of some chemical nutrients in four Brazilian tropical seaweeds

    Directory of Open Access Journals (Sweden)

    José Gerardo Carneiro

    2014-05-01

    Full Text Available Seaweeds have various chemical components with beneficial effects for human use; however, their nutritional values in Brazilian species are not well known. This study aimed to evaluate the content of water, ash, protein, carbohydrate, and lipid in four seaweeds (Hypnea musciformis, Solieria filiformis, Caulerpa cupressoides and C. mexicana. Algal constituents were determined by difference, gravimetric or colorimetric method, being the values expressed as g 100 g-1 dehydrated weight (d.w.. Results revealed that the water (10.7 ± 0.18-15.06 ± 1.14 g 100 g-1 d.w., ash (7.79 ± 0.87-15.12 ± 0.51 g 100 g-1 d.w, protein (17.12 ± 0.99-20.79 ± 0.58 g 100 g-1 d.w., lipid (0.33 ± 0.01-3.77 ± 0.13 g 100 g-1 d.w. and carbohydrate (38.07 ± 0.32-54.24 ± 0.157 g 100 g-1 d.w. contents varied between the species (p < 0.05. H. musciformis and S. filiformis (Rhodophyta had highest ash contents (14.14 ± 1.23-15.12 ± 0.51 g 100 g-1 d.w., whereas lipids were higher for Caulerpa species (Chlorophyta (1.52 ± 0.17-3.77 ± 0.13 g 100 g-1 d.w. (p < 0.05. Protein and carbohydrate were the most sources in all the species. Therefore, the studied seaweeds could be a potential source of food ingredients for diets.

  9. Different Models Used to Interpret Chemical Changes: Analysis of a Curriculum and Its Impact on French Students' Reasoning

    Science.gov (United States)

    Kermen, Isabelle; Meheut, Martine

    2009-01-01

    We present an analysis of the new French curriculum on chemical changes describing the underlying models and highlighting their relations to the empirical level. The authors of the curriculum introduced a distinction between the chemical change of a chemical system and the chemical reactions that account for it. We specify the different roles of…

  10. A methodology for chemical hazards analysis at nuclear fuels reprocessing plants

    International Nuclear Information System (INIS)

    The Savannah River Laboratory employs a formal methodology for chemical hazards analysis primarily for use in the risk assessment of its nuclear fuels reprocessing plants. The methodology combines interactive matrices for reactions of available materials, fault tree analysis, human factors, and extensive data banks on the operating history of the plants. Examples illustrate the methodology and a related data bank

  11. Study of multi-site chemical exchange in solution state by NMR: 1D experiments with multiply selective excitation

    Indian Academy of Sciences (India)

    Samanwita Pal

    2010-07-01

    Chemical exchange in solution state has been investigated traditionally by both 1D and 2D NMR, permitting the extraction of kinetic parameters (e.g. the spin-lattice relaxation time 1, the exchange rate constant and the activation parameters). This work demonstrates a simple 1D NMR approach employing multiply selective excitation to study multi-site exchange processes in solution, applying it to systems that exhibit three-site exchange. This approach involves simultaneous excitation of all - or a chosen subset of - the exchanging sites by using an appropriately modulated shaped radiofrequency pulse. The pulse sequence, as well as analysis is summarized. Significant features of the experiment, which relies on sign labelling of the exchanging sites, include considerably shorter experiment time compared to standard 2D exchange work, clear definition of the exchange time window and uniform pulse non-ideality effects for all the exchanging sites. Complete kinetic information is reported in the study of dynamic processes in superacid solutions of two weak bases, studied by 1H NMR. An analytical solution, leading to the determination of four rate parameters, is presented for proton exchange studies on these systems, which involve a mixture of two weak bases in arbitrary concentration ratio, and stoichiometric excess of the superacid.

  12. 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.

  13. The Matthew effect in environmental science publication: A bibliometric analysis of chemical substances in journal articles

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Eriksen, Mette Lindholm; Ellegaard, Ole;

    2011-01-01

    publication rates. The persistence in the scientific literature of the top-20 chemicals was only weakly related to their publication in journals with a high impact factor, but some substances achieved high citation rates. Conclusions The persistence of some environmental chemicals in the scientific literature......Background While environmental research addresses scientific questions of possible societal relevance, it is unclear to what degree research focuses on environmental chemicals in need of documentation for risk assessment purposes. Methods In a bibliometric analysis, we used SciFinder to extract...... Chemical Abstract Service (CAS) numbers for chemicals addressed by publications in the 78 major environmental science journals during 2000-2009. The Web of Science was used to conduct title searches to determine longterm trends for prominent substances and substances considered in need of research...

  14. The influence of chemical composition and mixing state of Los Angeles urban aerosol on CCN number and cloud properties

    Directory of Open Access Journals (Sweden)

    M. J. Cubison

    2008-03-01

    Full Text Available The relationship between cloud condensation nuclei (CCN number and the physical and chemical properties of the atmospheric aerosol distribution is explored for a polluted urban data set from the Study of Organic Aerosols at Riverside I (SOAR-1 campaign conducted at Riverside, California, USA during summer 2005. The mixing state and, to a lesser degree, the average chemical composition are shown to be important parameters in determining the activation properties of those particles around the critical activation diameters for atmospherically-realistic supersaturation values. Closure between predictions and measurements of CCN number at several supersaturations is attempted by modeling a number of aerosol chemical composition and mixing state schemes of increasing complexity. It is shown that a realistic treatment of the state of mixing of the urban aerosol distribution is critical in order to eliminate model bias. Fresh emissions such as elemental carbon and small organic particles must be treated as non-activating and explicitly accounted for in the model scheme. The relative number concentration of these particles compared to inorganics and oxygenated organic compounds of limited hygroscopicity plays an important role in determining the CCN number. Furthermore, expanding the different composition/mixing state schemes to predictions of cloud droplet number concentration in a cloud parcel model highlights the dependence of cloud optical properties on the state of mixing and hygroscopic properties of the different aerosol modes, but shows that the relative differences between the different schemes are reduced compared to those from the CCN model.

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

    International Nuclear Information System (INIS)

    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

  16. Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

    Directory of Open Access Journals (Sweden)

    S. Decesari

    2014-04-01

    Full Text Available The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterized by a less dense urbanization. We present here the results obtained in San Pietro Capofiume, which is located in a sparsely inhabited sector of the Po Valley, Italy. The experiment was carried out in summer 2009 in the framework of the EUCAARI project ("European Integrated Project on Aerosol, Cloud Climate Aerosol Interaction". For the first time in Europe, six state-of-the-art techniques were used in parallel: (1 on-line TSI aerosol time-of-flight mass spectrometer (ATOFMS, (2 on-line Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS, (3 soot particle aerosol mass spectrometer (SP-AMS, (4 on-line high resolution time-of-flight mass spectrometer-thermal desorption aerosol gas chromatograph (HR-ToFMS-TAG, (5 off-line twelve-hour resolution proton nuclear magnetic resonance (H-NMR spectroscopy, and (6 chemical ionization mass spectrometry (CIMS for the analysis of gas-phase precursors of secondary aerosol. Data from each aerosol spectroscopic method were analysed individually following ad-hoc tools (i.e. PMF for AMS, Art-2a for ATOFMS. The results obtained from each techniques are herein presented and compared. This allows us to clearly link the modifications in aerosol chemical composition to transitions in air mass origin and meteorological regimes. Under stagnant conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black

  17. Theoretical considerations of Flow Injection Analysis in the Absence of Chemical Reactions

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2000-01-01

    The fundamental mechanism of flow injection analysis (FIA) is assumed to be simple dissusion and the response of the detector is included in a model description that provide information about the shape of the FIA peak in terms of, basically, five parameters. Two of the five parameters are associa...... any deviation from the features of the present model and the results of a tentative chemical reaction with one of the test compounds, is related to chemical kinetics....

  18. Physico Chemical Analysis of Sapota (Manilkara zapota) Coated by Edible Aloe Vera Gel

    OpenAIRE

    N.Padmaja; S. John Don Bosco; J. Sudhakara Rao

    2015-01-01

    The physical and chemical characteristics of the fruit have immense significance as they ultimately affect the quality of processed productsprepared from them. Over ripening of Sapota (Manilkara zapota) fruits at the post-harvest stage usually results in dramatic decline in quality.In the present study, physico chemical analysis (which includes Weight loss, Colour, Texture, TSS, pH, TA and Ascorbic acid content) ofedible Aloe vera gel coated Sapota fruits packed in LDPE and stored at 15 ± 2? ...

  19. Permeability and chemical analysis of aromatic polyamide based membranes exposed to sodium hypochlorite

    OpenAIRE

    Ettori, Axel; Gaudichet-Maurin, Emmanuelle; Schrotter, Jean-Christophe; Aimar, Pierre; Causserand, Christel

    2011-01-01

    In this study, a cross-linked aromatic polyamide based reverse osmosis membrane was exposed to variable sodium hypochlorite ageing conditions (free chlorine concentration, solution pH) and the resulting evolutions of membrane surface chemical and structural properties were monitored. Elemental and surface chemical analysis performed using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), showed that chlorine is essentially incorporated on the polyamide...

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

    OpenAIRE

    Centeno, José A.; Duane A. Rogers; Gijsbert B. van der Voet; Elisa Fornero; Lingsu Zhang; Mullick, Florabel G.; Chapman, Gail D.; Olabisi, Ayodele O.; Wagner, Dean J.; Alexander Stojadinovic; Potter, Benjamin K.

    2014-01-01

    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 rega...

  1. 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)

    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 TR2O3 (rare earth oxides) in the UTM effluents. The SO4 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)

  2. Critical state analysis using continuous reading SQUID magnetometer

    Czech Academy of Sciences Publication Activity Database

    Janů, Zdeněk; Švindrych, Zdeněk; Youssef, A.; Baničová, L.

    Rijeka : Intech, 2011 - (Luiz, A.), s. 261-276 ISBN 978-953-307-151-0 R&D Projects: GA ČR GA202/08/0722 Institutional research plan: CEZ:AV0Z10100520 Keywords : thin superconducting films * critical state * critical current density Subject RIV: BM - Solid Matter Physics ; Magnetism http://www.intechopen.com/articles/show/title/critical-state-analysis-using-continuous-reading- squid -magnetometer

  3. Analysis of abused drugs by selected ion monitoring: quantitative comparison of electron impact and chemical ionization

    International Nuclear Information System (INIS)

    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

  4. Ab initio calculations and analysis of chemical bonding in SrTiO3 and SrZrO3 cubic crystals

    Science.gov (United States)

    Evarestov, R. A.; Tupitsyn, I. I.; Bandura, A. V.; Alexandrov, V. E.

    The possibility of the different first-principles methods to describe the chemical bonding in SrTiO3 and SrZrO3 cubic crystals is investigated. The local properties of the electronic structure (atomic charges, bond orders, atomic delocalization indexes, and polarization fractions) were calculated with different methods: traditional Mulliken population analysis in LCAO calculations, two projection techniques in plane-wave (PW) calculations, population analysis based on Wannier-type atomic orbitals, and chemical bonding analysis based on the localized Wannier functions for occupied (valence band) LCAO states. All the techniques considered except the traditional Mulliken analysis demonstrate that the ionicity of chemical bonding in SrZrO3 is larger than in SrTiO3, in agreement with the Zr and Ti electronegativities relation and the relative bandgaps observed.

  5. 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

  6. 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. PMID:27222376

  7. Analysis and Modelling of the Steady-State and Dynamic-State Discharge in SMES System

    Science.gov (United States)

    Chen, Xiao Yuan; Jin, Jian Xun

    The steady-state and dynamic-state discharge processes have been discussed to develop a superconducting magnetic energy storage (SMES) model in the paper. The SMES model allows the integrated analysis and optimization of the SMES devices, and their control systems, and can also serve as an independent storage module in the practical SMES application circuits, thus provide a method to link superconductivity technology to conventional power electronics in a SMES device.

  8. Chemical analysis of Asymptotic Giant Branch stars in M62

    CERN Document Server

    Lapenna, E; 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 M62 (NGC6266). Here we present the detailed abundance analysis of iron, titanium, and light-elements (O, Na, Al and Mg). For the majority (5 out 6) of the AGB targets we find that the abundances, of both iron and titanium, determined from neutral lines are significantly underestimated with respect to those obtained from ionized features, the latter being, instead, in agreement with those measured for the RGB targets. This is similar to recent findings in other clusters and may suggest the presence of Non-Local Thermodynamical Equilibrium (NLTE) effects. In the O-Na, Al-Mg and Na-Al planes, the RGB stars show the typical correlations observed for globular cluster stars. Instead, all the AGB targets are clumped in the regions where first generation stars are expected to lie, similarly to what recently found for the AGB population of NGC6752. W...

  9. Chemical and Nutrient Analysis of Gingerbread Plum (Neocarya macrophylla Seeds

    Directory of Open Access Journals (Sweden)

    Tidjani Amza

    2010-07-01

    Full Text Available The proximate composition of gingerbread plum (Neocarya macrophylla seeds, mineral, fatty acid and amino acid compositions were evaluated. The proximate analysis revealed the following composition: moisture 10.57 and 10%, ash 4.43 and 6.43%, fat 47.28 and 2.14%, crude protein 20.37 and 61.71%, carbohydrates 8.64 and 12.10% and crude fiber 8.70 and 7.37% for Gingerbread Plum Seed Flour (GPSF and Defatted Gingerbread Plum Seed Flour (DGPSF respectively. Oleic, linoleic and arachidonic acids were the major unsaturated fatty acids with 47.15, 19.10 and 17.64% respectively. Saturated fatty acids accounted for 14.72% of total fatty acids. The main saturated fatty acids were palmitic and stearic, with minute amounts of arachidic. Magnesium, potassium and calcium were the predominant elements present in the seeds. Copper, iron and manganese were also detected in appreciable amounts. Essential amino acids were above the recommended amount by Food Agricultural Organization/W orld Health Organization (FAO/WHO for humans. The results of the present investigation showed that gingerbread plum seeds are a rich source of many important nutrients that appear to have a very positive effect on human health.

  10. Sustainability in the Design, Synthesis and Analysis of Chemical Engineering Processes 1st edition

    Science.gov (United States)

    This book preface explains the needs found by the book editors for assembling the state of the art of technical and scientific knowledge relevant to chemical engineering, sustainability, and sustainable uses of wastes and materials management, and to do so in an accessible and c...

  11. Dynamic thermal analysis of machines in running state

    CERN Document Server

    Wang, Lihui

    2014-01-01

    With the increasing complexity and dynamism in today’s machine design and development, more precise, robust and practical approaches and systems are needed to support machine design. Existing design methods treat the targeted machine as stationery. Analysis and simulation are mostly performed at the component level. Although there are some computer-aided engineering tools capable of motion analysis and vibration simulation etc., the machine itself is in the dry-run state. For effective machine design, understanding its thermal behaviours is crucial in achieving the desired performance in real situation. Dynamic Thermal Analysis of Machines in Running State presents a set of innovative solutions to dynamic thermal analysis of machines when they are put under actual working conditions. The objective is to better understand the thermal behaviours of a machine in real situation while at the design stage. The book has two major sections, with the first section presenting a broad-based review of the key areas of ...

  12. Chemical Analysis of Asymptotic Giant Branch Stars in M62

    Science.gov (United States)

    Lapenna, E.; Mucciarelli, A.; Ferraro, F. R.; Origlia, L.; Lanzoni, B.; Massari, D.; Dalessandro, E.

    2015-11-01

    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). For the majority (five out of six) of the AGB targets, we find that the abundances of both iron and titanium determined from neutral lines are significantly underestimated with respect to those obtained from ionized features, the latter being, instead, in agreement with those measured for the RGB targets. This is similar to recent findings in other clusters and may suggest the presence of nonlocal thermodynamic equilibrium (NLTE) effects. In the O-Na, Al-Mg, and Na-Al planes, the RGB stars show the typical correlations observed for GC stars. Instead, all the AGB targets are clumped in the regions where first-generation stars are expected to lie, similar to what was recently found for the AGB population of NGC 6752. While the sodium and aluminum abundances could be underestimated as a consequence of the NLTE bias affecting iron and titanium, the oxygen line used does not suffer from the same effects, and the lack of O-poor AGB stars therefore is a solid result. We can thus conclude that none of the investigated AGB stars belongs to the second stellar generation of M62. We also find an RGB star with extremely high sodium abundance ([Na/Fe] = +1.08 dex). Based on observations collected at the ESO-VLT (Cerro Paranal, Chile) under program 193.D-0232. Also based on observations (GO10120 and GO11609) with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

  13. Multivariate data analysis for depth resolved chemical classification and quantification of sulfur in SNMS

    Science.gov (United States)

    Sommer, M.; Goschnick, J.

    2005-09-01

    The quantification of elements in quadrupole based SNMS is hampered by superpositions of atomic and cluster signals. Moreover, the conventional SNMS data evaluation employs only atomic signals to determine elemental concentrations, which not allows any chemical specifications of the determined elements. Improvements in the elemental quantification and additional chemical information can be obtained from kinetic energy analysis and the inclusion of molecular signals into mass spectra evaluation. With the help of multivariate data analysis techniques, the combined information is used for the first time for a quantitative and chemically distinctive determination of sulfur. The kinetic energy analysis, used to solve the interference of sulfur with O 2 at masses 32-34 D, turned out to be highly important for the new type of evaluation.

  14. 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. PMID:27311789

  15. U.S. Aerospace and Aviation Industry: A State-By-State Analysis

    Science.gov (United States)

    2002-01-01

    President George W. Bush and the Congress created the Commission on the Future of the United States Aerospace Industry to evaluate the current and future health of the industry as well as the challenges that lie ahead for the U.S. workforce and the economy. To accomplish our mission, we commissioned a study on the economic impact of the aerospace industry nationally and on a state-by-state basis, using the best available U.S. government data. This study sought to define the core of the aerospace industry. The resulting data represents that very core those jobs specifically tied to commercial and civilian aerospace. U.S. Aerospace and Aviation: A State-by-State Analysis examines the civilian and commercial aerospace and aviation industry by employment, wages, payroll, and establishments. The report found that the U.S. civilian and commercial aerospace and aviation industry employed over 2 million workers in 2001.

  16. Measurement of cardiovascular state using attractor reconstruction analysis

    OpenAIRE

    Charlton, Peter Harcourt; Camporota, Luigi; Smith, John; Nandi, Manasi; Christie, Mark Ian; Aston, Philip; Beale, Richard

    2015-01-01

    Attractor reconstruction (AR) analysis has been used previously to quantify the variability in arterial blood pressure (ABP) signals. Since ABP signals are only available in a minority of clinical scenarios, we sought to determine whether AR could also be performed on more widely available photoplethysmogram (PPG) signals. AR analysis was performed on simultaneous ABP and PPG signals before, during and after a change in cardiovascular state. A novel quality metric was used to eliminate window...

  17. Morphological and chemical analysis of different precipitates on mineral trioxide aggregate immersed in different fluids.

    Science.gov (United States)

    Han, Linlin; Okiji, Takashi; Okawa, Seigo

    2010-10-01

    The purpose of this study was to analyze the ultrastructures and chemical compositions of precipitates formed on mineral trioxide aggregate (MTA; White ProRoot MTA) immersed in distilled water (DW) or phosphate buffered saline (PBS), based on the attribution that MTA's bioactivity and sealing ability are influenced by its interaction with the external fluid environment. After 1 and 14 days of immersion, precipitates formed on MTA disks were analyzed using wavelength-dispersive X-ray spectroscopy electron probe microanalyzer with image observation function (SEM-EPMA; EPMA1601, Shimadzu, Kyoto, Japan), and Fourier transform-infrared (FT-IR) spectroscopy. On DW specimens, cubic-like crystals containing Ca, O, and C (17, 66, and 17 at% respectively) were produced. State analysis of calcium k(β)spectrum also revealed calcium hydroxide. On PBS specimens, acicular-spherical and lath-like crystals with Ca/P molar ratios of 1.42 and 1.58 respectively were produced. In conclusion, the precipitates formed on DW specimens were identified as calcium carbonate and calcium hydroxide primarily, whereas the precipitates on PBS specimens were inferred to be amorphous calcium phosphate. PMID:20823620

  18. 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

  19. The prediction of PAHs bioavailability in soils using chemical methods: state of the art and future challenges.

    Science.gov (United States)

    Cachada, A; Pereira, R; da Silva, E Ferreira; Duarte, A C

    2014-02-15

    The evaluation of the available fraction of hydrophobic organic contaminants (HOCs) is extremely important for assessing their risk to the environment and human health. This available fraction, which can be solubilized and/or easily extracted, is believed to be the most accessible for bioaccumulation, biosorption and/or transformation by organisms. Based on this, two main types of chemical methods have been developed, closely related to the concepts of bioaccessibility and freely available concentrations: non-exhaustive extractions and biomimetic methods. Since bioavailability is species and compound specific, this work focused only in one of the most widespread group of HOCs in soils: polycyclic aromatic hydrocarbons (PAHs). This study aims at producing a state of the art knowledge base on bioavailability and chemical availability of PAHs in soils, clarifying which chemical methods can provide a better prediction of an organism exposure, and which are the most promising ones. Therefore, a review of the processes involved on PAHs availability to microorganisms, earthworms and plants was performed and the outputs given by the different chemical methods were evaluated. The suitability of chemical methods to predict bioavailability of the 16 US EPA PAHs in dissimilar naturally contaminated soils was not yet demonstrated, being especially difficult for high molecular weight compounds. Even though the potential to predict microbial mineralization using non-exhaustive extractions is promising, it will be very difficult to achieve for earthworms and plants, due to the complexity of accumulation mechanisms which are not taken into account by chemical methods. Yet, the existing models could be improved by determining compound, species and site specific parameters. Moreover, chemical availability can be very useful to understand the bioavailability processes and the behavior of PAHs in soils. The inclusion of chemical methods on risk assessment has been suggested and it is

  20. Análise físico-química dos méis das abelhas Apis mellifera e Melipona scutellaris produzidos em regiões distintas no Estado da Paraíba Physical-Chemical analysis of honeybee Apis mellifera and Melipona scutellaris on two regions at Paraiba State, Brazil

    Directory of Open Access Journals (Sweden)

    Adriana Evangelista-Rodrigues

    2005-10-01

    determination its quality for commercialization. The objective of this work was the physical-chemical analysis of honeybee Apis mellifera and Melipona scutellaris to Brejo and Cariri (Paraíba State Brazil. With the gotten results, it was observed that the honeybee M. scutellaris presents a bigger water text (25.25% humidity when compared with the honeybee A. mellifera (18.76%, making difficult its storage, with lower time of shelf life. It had, as reply to the hidroximetilfurfural analyses, higher value for the honey produced in the Cariri when compared with the honey produced in the Brejo, what it can be explained by the difference temperature, of being higher in the Cariri. For the pH values was made as to the significance of the differences between the honeys was gotten, with the honey of the Cariri presenting lower value (3.8. For Total Acidity, the honeybee A. mellifera of the Brejo presented 41.6 meq/kg of honey, while the native honey presented 28.3 meq/kg of honey. For the too much studied parameters it didn't have significant difference between the group. As conclusion the analytical results on the honeys produced indicate a good level of quality both A.mellifera and M. scutellaris. The parameters indicatiing a shelf life of the product were most satisfactory.

  1. Electronic Structure, Oxidation State of Sn, and Chemical Stability of Photovoltaic Perovskite Variant Cs2SnI6

    CERN Document Server

    Xiao, Zewen; Zhang, Xiao; Zhou, Yuanyuan; Hosono, Hideo; Kamiya, Toshio

    2015-01-01

    Cs2SnI6, a variant of perovskite CsSnI3, is expected for a photovoltaic material. Based on a simple ionic model, it is expected that Cs2SnI6 is composed of Cs+, I-, and Sn4+ ions and that the band gap is primarily made of occupied I- 5p6 valence band maximum (VBM) and unoccupied Sn4+ 5s conduction band minimum (CBM) similar to SnO2. In this work, we performed density functional theory (DFT) calculations and revealed that the real charge state of the Sn ion in this compound is +2 similar to CsSnI3. This is due to strong covalent nature between the I ion and the Sn ion, the VBM consists of I 5p - I 5p antibonding states, and the CBM of I 5p - Sn 5s antibonding states. The +2 oxidation state of Sn is realized by the apparent charge state of I-2/3, because the I 5p - Sn 5s antibonding states form the unoccupied CBM and apparently 1/18 of the I 5p orbitals are unoccupied. These results are further supported by comparing chemical bonding analyses with those of related compounds. The chemical stability of the Cs2SnI...

  2. Institute of Chemical Process Fundamentals of the ASCR: State of the Art

    Czech Academy of Sciences Publication Activity Database

    Hanika, Jiří

    2013-01-01

    Roč. 62, 5-6 (2013), s. 210-241. ISSN 0022-9830 Institutional support: RVO:67985858 Keywords : fundamental research * multi-disciplinary character * external cooperation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  3. SOURCE ASSESSMENT: CHEMICAL AND FERTILIZER MINERAL INDUSTRY, STATE-OF-THE-ART

    Science.gov (United States)

    Air and water pollutants are generated during the conversion of naturally occurring minerals into suitable forms for use in chemical and fertilizer production. These minerals are barite, borates, fluorspar, lithium minerals, mineral pigments, phosphate rock, potash, salt, sodium ...

  4. The SFM/ToF-SIMS combination for advanced chemically-resolved analysis at the nanoscale

    International Nuclear Information System (INIS)

    The combination of Time-of-flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Scanning Force Microscopy (SFM) allows the 3D-compositional analysis of samples or devices. Typically, the topographical data obtained by SFM is used to determine the initial sample topography and the absolute depth of the ToF-SIMS analysis. Here ToF-SIMS and SFM data sets obtained on 2 prototypical samples are explored to go beyond conventional 3D-compositional analysis. SFM topographical and material contrast maps are combined with ToF-SIMS retrospective analysis to detect features that would have escaped a conventional ToF-SIMS data analysis. In addition, SFM data is used to extrapolate the chemical information beyond the spatial resolution of ToF-SIMS, allowing the mapping of the chemical composition at the nanoscale

  5. 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.

  6. Study on the chemical species of platinum group elements in geological samples by molecular activation analysis

    International Nuclear Information System (INIS)

    The chemical species of platinum group elements in some upper mantle-derived xenoliths from Eastern China are studied by molecular activation analysis, in which the chemical stepwise dissolution, nickel fire assay preconcentration and neutron activation analysis are jointly applied. The weighted sums of platinum group elements in 6 phases are in agreement with their total contents. The distribution patterns of platinum group elements in sulphides show that sulphide segregation is one of the important mechanisms for the fractionation of platinum group elements in upper mantle-derived material during partial melting

  7. 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.

  8. Participation in the 1999 IAEA interlaboratory comparison on chemical analysis of groundwater

    International Nuclear Information System (INIS)

    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, HCO3, Cl, SO4, NO3, SiO2, 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

  9. Analysis of Member State RED implementation. Final Report (Task 2)

    Energy Technology Data Exchange (ETDEWEB)

    Peters, D.; Alberici, S.; Toop, G. [Ecofys, Utrecht (Netherlands); Kretschmer, B. [Institute for European Environmental Policy IEEP, London (United Kingdom)

    2012-12-15

    This report describes the way EU Member States have transposed the sustainability and chain of custody requirements for biofuels as laid down in the Renewable Energy Directive (RED) and Fuel Quality Directive (FQD). In the assessment of Member States' implementation, the report mainly focuses on effectiveness and administrative burden. Have Member States transposed the Directives in such a way that compliance with the sustainability criteria can be ensured as effectively as possible? To what extent does the Member States' implementation lead to unnecessary administrative burden for economic operators in the (bio)fuel supply chain? The report focuses specifically on the transposition of the sustainability and chain of custody requirements, not on the target for renewables on transport. This means that for example the double counting provision is not included as part of the scope of this report. This report starts with an introduction covering the implementation of the Renewable Energy (and Fuel Quality) Directive into national legislation, the methodology by which Member States were assessed against effectiveness and administrative burden and the categorisation of Member State's national systems for RED-implementation (Chapter 1). The report continues with a high level description of each Member State system assessed (Chapter 2). Following this, the report includes analysis of the Member States on the effectiveness and administrative burden of a number of key ('major') measures (Chapter 3). The final chapter presents the conclusions and recommendations (Chapter 4)

  10. State of chemical modeling modules for the degradation of concrete and cements

    Energy Technology Data Exchange (ETDEWEB)

    Meike, A.

    1997-04-15

    This report describes the conceptual framework upon which modeling activities will be needed to predict the chemistry of water in contact with concrete and its degradation products cover a broad area, from developing databases for existing abiotic codes, to developing codes that can simulate the chemical impact of microbial activities at a level of sophistication equivalent to that of the abiotic modeling codes, and ultimately, to simulating drift-scale chemical systems in support of hydrological, geochemical,a nd engineering efforts.

  11. State Space Analysis of Hierarchical Coloured Petri Nets

    DEFF Research Database (Denmark)

    Christensen, Søren; Kristensen, Lars Michael

    2003-01-01

    present a tool in which formal verification, partial state spaces, and analysis by means of graphical feedback and simulation are integrated entities. The focus of the paper is twofold: the support for graphical feedback and the way it has been integrated with simulation, and the underlying algorithms and...

  12. Analysis of steady-state hydraulic tests in fractured rock

    International Nuclear Information System (INIS)

    A model for the analysis of steady-state hydraulic injection tests into single fractures of a rock-mass is presented, and solved analytically. It is used to obtain a probability distribution for the transmissivities of fractures in Cornish granite. (author)

  13. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth : Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers.

    Science.gov (United States)

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity. PMID:26508401

  14. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth. Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers

    Science.gov (United States)

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

  15. Stability analysis of axisymmetric supersonic wakes using various basic states

    International Nuclear Information System (INIS)

    Two-dimensional stability analyses are conducted of turbulent axisymmetric supersonic wakes at M = 2.46. The aim is to investigate which azimuthal modes are dominant and how the stability behaviour is influenced by the choice of basic state. To that end, axisymmetric (two dimensional) and three dimensional direct numerical simulations (DNS) with either laminar or turbulent inflow conditions were conducted of supersonic wakes to provide the respective basic states for the stability analysis. The global stability analyses were then performed by computing the temporal pulse response using forced Navier-Stokes simulations for each basic state. Using the time- and azimuthally-averaged data from the 3D DNS with turbulent inflow as basic state, an absolute instability of the axisymmetric mode at a Reynolds number, based on wake-generating body diameter and freestream velocity, ReD = 100,000 was found. This is in contrast to results obtained earlier using an axisymmetric flow solution as the basic state. The linear stability analysis for all basic states is presented showing the temporal growth of various azimuthal modes and the respective radial mode shapes. The results are also contrasted to those obtained from nonlinear DNS.

  16. Applying Chemical Imaging Analysis to Improve Our Understanding of Cold Cloud Formation

    Science.gov (United States)

    Laskin, A.; Knopf, D. A.; Wang, B.; Alpert, P. A.; Roedel, T.; Gilles, M. K.; Moffet, R.; Tivanski, A.

    2012-12-01

    The impact that atmospheric ice nucleation has on the global radiation budget is one of the least understood problems in atmospheric sciences. This is in part due to the incomplete understanding of various ice nucleation pathways that lead to ice crystal formation from pre-existing aerosol particles. Studies investigating the ice nucleation propensity of laboratory generated particles indicate that individual particle types are highly selective in their ice nucleating efficiency. This description of heterogeneous ice nucleation would present a challenge when applying to the atmosphere which contains a complex mixture of particles. Here, we employ a combination of micro-spectroscopic and optical single particle analytical methods to relate particle physical and chemical properties with observed water uptake and ice nucleation. Field-collected particles from urban environments impacted by anthropogenic and marine emissions and aging processes are investigated. Single particle characterization is provided by computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). A particle-on-substrate approach coupled to a vapor controlled cooling-stage and a microscope system is applied to determine the onsets of water uptake and ice nucleation including immersion freezing and deposition ice nucleation as a function of temperature (T) as low as 200 K and relative humidity (RH) up to water saturation. We observe for urban aerosol particles that for T > 230 K the oxidation level affects initial water uptake and that subsequent immersion freezing depends on particle mixing state, e.g. by the presence of insoluble particles. For T cloud formation. Initial results applying single particle IN analysis using CCSEM/EDX and STXM/NEXAFS reveal that a significant amount of IN are coated by organics and, thus, are similar to the

  17. Excited state properties of the astaxanthin radical cation: A quantum chemical study

    Science.gov (United States)

    Dreuw, Andreas; Starcke, Jan Hendrik; Wachtveitl, Josef

    2010-07-01

    Using time-dependent density functional theory, the excited electronic states of the astaxanthin radical cation (AXT rad + ) are investigated. While the optically allowed excited D 1 and D 3 states are typical ππ∗ excited states, the D 2 and D 4 states are nπ∗ states. Special emphasis is put onto the influence of the carbonyl groups onto the excited states. For this objective, the excited states of four hypothetical carotenoids and zeaxanthin have been computed. Addition of a carbonyl group to a conjugated carbon double bond system does essentially not change the vertical excitation energies of the optically allowed ππ∗ states due to two counter-acting effects: the excitation energy should increase due to the -M-effect of the carbonyl group and at the same time decrease owing to the elongation of the conjugated double bond system by the carbonyl group itself.

  18. Excited state properties of the astaxanthin radical cation: A quantum chemical study

    Energy Technology Data Exchange (ETDEWEB)

    Dreuw, Andreas, E-mail: andreas.dreuw@theochem.uni-frankfurt.de [Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max von Laue-Str. 7, 60438 Frankfurt am Main (Germany); Starcke, Jan Hendrik; Wachtveitl, Josef [Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max von Laue-Str. 7, 60438 Frankfurt am Main (Germany)

    2010-07-19

    Using time-dependent density functional theory, the excited electronic states of the astaxanthin radical cation (AXT{sup {center_dot}+}) are investigated. While the optically allowed excited D{sub 1} and D{sub 3} states are typical {pi}{pi}* excited states, the D{sub 2} and D{sub 4} states are n{pi}* states. Special emphasis is put onto the influence of the carbonyl groups onto the excited states. For this objective, the excited states of four hypothetical carotenoids and zeaxanthin have been computed. Addition of a carbonyl group to a conjugated carbon double bond system does essentially not change the vertical excitation energies of the optically allowed {pi}{pi}* states due to two counter-acting effects: the excitation energy should increase due to the -M-effect of the carbonyl group and at the same time decrease owing to the elongation of the conjugated double bond system by the carbonyl group itself.

  19. Excited state properties of the astaxanthin radical cation: A quantum chemical study

    International Nuclear Information System (INIS)

    Using time-dependent density functional theory, the excited electronic states of the astaxanthin radical cation (AXT·+) are investigated. While the optically allowed excited D1 and D3 states are typical ππ* excited states, the D2 and D4 states are nπ* states. Special emphasis is put onto the influence of the carbonyl groups onto the excited states. For this objective, the excited states of four hypothetical carotenoids and zeaxanthin have been computed. Addition of a carbonyl group to a conjugated carbon double bond system does essentially not change the vertical excitation energies of the optically allowed ππ* states due to two counter-acting effects: the excitation energy should increase due to the -M-effect of the carbonyl group and at the same time decrease owing to the elongation of the conjugated double bond system by the carbonyl group itself.

  20. Characterization of soil chemical properties of strawberry fields using principal component analysis

    Directory of Open Access Journals (Sweden)

    Gláucia Oliveira Islabão

    2013-02-01

    Full Text Available One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component analysis (PCA. Soil sampling was based on topography, dividing the field in three thirds: upper, middle and lower. From each of these thirds, five soil samples were randomly collected in the 0-0.20 m layer, to form a composite sample for each third. Four samples were taken during the strawberry cycle and the following properties were determined: soil organic matter (OM, soil total nitrogen (N, available phosphorus (P and potassium (K, exchangeable calcium (Ca and magnesium (Mg, soil pH (pH, cation exchange capacity (CEC at pH 7.0, soil base (V% and soil aluminum saturation(m%. No spatial variation was observed for any of the studied soil fertility parameters in the strawberry fields and temporal variation was only detected for available K. Phosphorus and K contents were always high or very high from the beginning of the strawberry cycle, while pH values ranged from very low to very high. Principal component analysis allowed the clustering of all strawberry fields based on variables related to soil acidity and organic matter content.

  1. Statistically optimal analysis of state-discretized trajectory data from multiple thermodynamic states.

    Science.gov (United States)

    Wu, Hao; Mey, Antonia S J S; Rosta, Edina; Noé, Frank

    2014-12-01

    We propose a discrete transition-based reweighting analysis method (dTRAM) for analyzing configuration-space-discretized simulation trajectories produced at different thermodynamic states (temperatures, Hamiltonians, etc.) dTRAM provides maximum-likelihood estimates of stationary quantities (probabilities, free energies, expectation values) at any thermodynamic state. In contrast to the weighted histogram analysis method (WHAM), dTRAM does not require data to be sampled from global equilibrium, and can thus produce superior estimates for enhanced sampling data such as parallel/simulated tempering, replica exchange, umbrella sampling, or metadynamics. In addition, dTRAM provides optimal estimates of Markov state models (MSMs) from the discretized state-space trajectories at all thermodynamic states. Under suitable conditions, these MSMs can be used to calculate kinetic quantities (e.g., rates, timescales). In the limit of a single thermodynamic state, dTRAM estimates a maximum likelihood reversible MSM, while in the limit of uncorrelated sampling data, dTRAM is identical to WHAM. dTRAM is thus a generalization to both estimators. PMID:25481128

  2. Statistically optimal analysis of state-discretized trajectory data from multiple thermodynamic states

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hao; Mey, Antonia S. J. S.; Noé, Frank [Free University of Berlin, Arnimallee 6, 14195 Berlin (Germany); Rosta, Edina [King' s College London, London, SE1 1DB (United Kingdom)

    2014-12-07

    We propose a discrete transition-based reweighting analysis method (dTRAM) for analyzing configuration-space-discretized simulation trajectories produced at different thermodynamic states (temperatures, Hamiltonians, etc.) dTRAM provides maximum-likelihood estimates of stationary quantities (probabilities, free energies, expectation values) at any thermodynamic state. In contrast to the weighted histogram analysis method (WHAM), dTRAM does not require data to be sampled from global equilibrium, and can thus produce superior estimates for enhanced sampling data such as parallel/simulated tempering, replica exchange, umbrella sampling, or metadynamics. In addition, dTRAM provides optimal estimates of Markov state models (MSMs) from the discretized state-space trajectories at all thermodynamic states. Under suitable conditions, these MSMs can be used to calculate kinetic quantities (e.g., rates, timescales). In the limit of a single thermodynamic state, dTRAM estimates a maximum likelihood reversible MSM, while in the limit of uncorrelated sampling data, dTRAM is identical to WHAM. dTRAM is thus a generalization to both estimators.

  3. Statistically optimal analysis of state-discretized trajectory data from multiple thermodynamic states

    International Nuclear Information System (INIS)

    We propose a discrete transition-based reweighting analysis method (dTRAM) for analyzing configuration-space-discretized simulation trajectories produced at different thermodynamic states (temperatures, Hamiltonians, etc.) dTRAM provides maximum-likelihood estimates of stationary quantities (probabilities, free energies, expectation values) at any thermodynamic state. In contrast to the weighted histogram analysis method (WHAM), dTRAM does not require data to be sampled from global equilibrium, and can thus produce superior estimates for enhanced sampling data such as parallel/simulated tempering, replica exchange, umbrella sampling, or metadynamics. In addition, dTRAM provides optimal estimates of Markov state models (MSMs) from the discretized state-space trajectories at all thermodynamic states. Under suitable conditions, these MSMs can be used to calculate kinetic quantities (e.g., rates, timescales). In the limit of a single thermodynamic state, dTRAM estimates a maximum likelihood reversible MSM, while in the limit of uncorrelated sampling data, dTRAM is identical to WHAM. dTRAM is thus a generalization to both estimators

  4. Application of physico-chemical procedures in the analysis of urinary calculi

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A.L.

    1985-01-01

    All physico-chemical techniques used in the analysis of urinary calculi have inherent advantages and limitations. Although x-ray powder diffraction can identify constituents unambiguously, certain minor components can be missed. Infrared spectroscopy is more sensitive but band assignment at low concentrations is difficult. Scanning electron microscopy together with energy dispersive x-ray analysis permits the simultaneous investigation of morphology and chemical microstructure. With the electron microprobe, minor constituents can be detected but tedious sample preparation procedures are required. Transmission electron microscopy is extremely useful in determining constituent inter-relationships and ultrastructure but ultramicrotomy is very difficult. Thermal gravimetric analysis gives quantitative information easily but does not satisfactorily distinguish between struvite and brushite. In an attempt to assess the accuracy of chemical analyses, 62 calculi were investigated applying several chemical tests. Those for MgS , PO4(T ), NHU and uric acid proved highly reliable while that for CaS often yielded an incorrect result. The test for oxalate was totally unsatisfactory. Investigators of stone composition and structure should include x-ray diffraction (or infrared spectroscopy) and scanning electron microscopy as their methods of first choice. In addition, chemical or thermogravimetric analyses should be utilized in an auxiliary capacity.

  5. Change of chemical states of niobium in the oxide layer of zirconium–niobium alloys with oxide growth

    International Nuclear Information System (INIS)

    The change of chemical states of niobium with oxide growth was examined in the oxide layers of Zr–2.5Nb around the first kinetic transition by the conversion electron yield – X-ray absorption near-edge structure measurements. The detailed depth profiles of niobium chemical states were obtained in both the pre- and the post-transition oxide layers of Zr–2.5Nb formed in water at 663 K for 40–280 d. The depth profiling revealed that the inner oxide layer remained protective to oxidizing species even though in the post-transition region and this excellent stability of barrierness would be attributed the suppression of hydrogen pickup. (author)

  6. Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network

    Directory of Open Access Journals (Sweden)

    Marchetto A

    2014-04-01

    Full Text Available Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network. Since 1997, atmospheric deposition was sampled and analyzed in the permanent plots of the Italian network for the evaluation of forest health (CONECOFOR, under the coordination of the Italian Forest Service. This paper presents the results of the activity carried out in 2009, when the EU-funded LIFE+ “FutMon” project allowed to extend the sampling network to 22 sites. Long-term trends will also be evaluated for the sampling sites with the longest time series. The sampling of open field bulk deposition was performed in a clearance close to the CONECOFOR permanent plots, while throughfall deposition and stemflow (in beech stand, only were sampled in the plot. Deposition samples were collected weekly and sent to the laboratories, where they were analyzed for pH, conductivity, major ions, and total carbon and nitrogen. Most measured variables showed a strong geographical gradient. For example, nitrogen deposition was relatively high in the Po plain (where the emissions of nitrogen oxides and ammonia are the highest and surrounding hills, reaching 10-20 kgN ha-1 y-1 in the open field and 13-25 kgN ha-1 y-1 in the throughfall. Sulphate deposition also showed a marked geographical gradient. Deposition of marine aerosol also had an important impact on the chemical composition of atmospheric deposition in Italy, together with the episodic deposition of Saharan dust, which showed a marked gradient, with highest values in the southernmost plots. Trend analysis was carried out on 10 sites running since the beginning of the program. A general negative trend in sulphate concentration was detected, paralleled in most plots by a positive trend in deposition pH, in good agreement with the strong reduction in the emission of sulphur dioxide recorded in the last decades. Nitrogen concentration also showed a significant decrease

  7. Forecasting global developments in the basic chemical industry for environmental policy analysis

    International Nuclear Information System (INIS)

    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 (CO2) 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 CO2 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 CO2 emissions rise by 50%, but climate policies may limit this to 30–40%. • Measures beyond energy efficiency are needed to prevent increasing CO2 emissions

  8. Ab initio analysis of magnetovolume versus chemical effects in CeRuSi and its hydride

    Science.gov (United States)

    Matar, Samir F.

    2007-03-01

    The change from heavy fermion to antiferromagnetic behavior of intermetallic system CeRuSi upon hydrogenation is addressed on bases of lattice expansion and chemical bonding effects within the density-functional theoretical framework using all electron scalar-relativistic augmented spherical wave method. While no magnetic moment develops in the 111 system, from total-energy differences, the hydride is found to be stable as an antiferromagnet in the ground state, in agreement with experiment. The role of anisotropic lattice expansion induced by hydrogen insertion is shown to be prevailing over the chemical bonding between hydrogen and the metallic species especially cerium.

  9. Quantum-Chemical Simulation of Solid-State NMR Spectra: The Example of a Molecular Tweezer Host-Guest Complex

    OpenAIRE

    Zienau, Jan; Kussmann, Joerg; Ochsenfeld, Christian

    2010-01-01

    Abstract A systematic quantum-chemical study of the convergence of proton NMR shieldings with the size of solid-state fragments is presented for a host-guest system. The largest system computed at Hartree-Fock and density-functional theory levels comprises a full first shell of complexes surrounding a central unit within an X-ray based structure and a total of 1196 atoms and 13260 basis functions. While the influence of methodological aspects can be considered ...

  10. State-of-the-art of screening methods for the rapid identification of chemicals in drinking water Deliverable D1

    OpenAIRE

    Llorca, Marta; Rodríguez-Mozaz, Sara

    2013-01-01

    The contamination of drinking water is potentially harmful and poses a risk to public health. If any observation suggests a potential contamination of drinking water, such as consumer complaints about the alteration of the water’s organoleptic properties, the appearance of health problems or an alarm triggered by sensors, a rapid identification of the hazard causing the problem is necessary. With regards to chemical contamination, EU Member States have several strategies to deal with the pres...

  11. Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network

    OpenAIRE

    Marchetto A; Arisci S.; Tartari GA; Balestrini R; Tait D

    2014-01-01

    Current state and temporal evolution of the chemical composition of atmospheric depositions in forest areas of the CONECOFOR network. Since 1997, atmospheric deposition was sampled and analyzed in the permanent plots of the Italian network for the evaluation of forest health (CONECOFOR), under the coordination of the Italian Forest Service. This paper presents the results of the activity carried out in 2009, when the EU-funded LIFE+ “FutMon” project allowed to extend the sampling network to 2...

  12. Chemical Analysis of Exhaled Human Breath Using High Resolution Mm-Wave Rotational Spectra

    Science.gov (United States)

    Guo, Tianle; Branco, Daniela; Thomas, Jessica; Medvedev, Ivan; Dolson, David; Nam, Hyun-Joo; O, Kenneth

    2014-06-01

    High resolution rotational spectroscopy enables chemical sensors that are both sensitive and highly specific, which is well suited for analysis of expired human breath. We have previously reported on detection of breath ethanol, methanol, acetone, and acetaldehyde using THz sensors. This paper will outline our present efforts in this area, with specific focus on our ongoing quest to correlate levels of blood glucose with concentrations of a few breath chemicals known to be affected by elevated blood sugar levels. Prospects, challenges and future plans will be outlined and discussed. Fosnight, A.M., B.L. Moran, and I.R. Medvedev, Chemical analysis of exhaled human breath using a terahertz spectroscopic approach. Applied Physics Letters, 2013. 103(13): p. 133703-5.

  13. 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. PMID:18093731

  14. 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.

  15. LANL organic analysis detection capabilities for chemical and biological warfare agents

    Energy Technology Data Exchange (ETDEWEB)

    Ansell, G.B.; Cournoyer, M.E.; Hollis, K.W.; Monagle, M.

    1996-12-31

    Organic analysis is the analytical arm for several Los Alamos National Laboratory (LANL) research programs and nuclear materials processes, including characterization and certification of nuclear and nonnuclear materials used in weapons, radioactive waste treatment and waste certification programs. Organic Analysis has an extensive repertoire of analytical technique within the group including headspace gas, PCBs/pesticides, volatile organics and semivolatile organic analysis. In addition organic analysis has mobile labs with analytic capabilities that include volatile organics, total petroleum hydrocarbon, PCBs, pesticides, polyaromatic hydrocarbons and high explosive screening. A natural extension of these capabilities can be applied to the detection of chemical and biological agents,

  16. Chemically modified Si(111) surfaces simultaneously demonstrating hydrophilicity, resistance against oxidation, and low trap state densities

    Science.gov (United States)

    Brown, Elizabeth S.; Hlynchuk, Sofiya; Maldonado, Stephen

    2016-03-01

    Chemically modified Si(111) surfaces have been prepared through a series of wet chemical surface treatments that simultaneously show resistance towards surface oxidation, selective reactivity towards chemical reagents, and areal defect densities comparable to unannealed thermal oxides. Specifically, grazing angle attenuated total reflectance infrared and X-ray photoelectron (XP) spectroscopies were used to characterize allyl-, 3,4-methylenedioxybenzene-, or 4-[bis(trimethylsilyl)amino]phenyl-terminated surfaces and the subsequently hydroxylated surfaces. Hydroxylated surfaces were confirmed through reaction with 4-(trifluoromethyl)benzyl bromide and quantified by XP spectroscopy. Contact angle measurements indicated all surfaces remained hydrophilic, even after secondary backfilling with CH3sbnd groups. Surface recombination velocity measurements by way of microwave photoconductivity transients showed the relative defect-character of as-prepared and aged surfaces. The relative merits for each investigated surface type are discussed.

  17. Supramolecular chemical shift reagents inducing conformational transitions: NMR analysis of carbohydrate homooligomer mixtures

    DEFF Research Database (Denmark)

    Beeren, Sophie; Meier, Sebastian

    2015-01-01

    We introduce the concept of supramolecular chemical shift reagents as a tool to improve signal resolution for the NMR analysis of homooligomers. Non-covalent interactions with the shift reagent can constrain otherwise flexible analytes inducing a conformational transition that results in signal...

  18. Fertilizer/Chemical Sales and Service Worker. Ohio's Competency Analysis Profile.

    Science.gov (United States)

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Ohio Competency Analysis Profile (OCAP), derived from a modified Developing a Curriculum (DACUM) process, is a current comprehensive and verified employer competency program list for fertilizer/chemical sales and service workers. Each unit (with or without subunits) contains competencies and competency builders that identify the occupational,…

  19. On the graph and systems analysis of reversible chemical reaction networks with mass action kinetics

    NARCIS (Netherlands)

    Rao, Shodhan; Jayawardhana, Bayu; Schaft, Arjan van der

    2012-01-01

    Motivated by the recent progresses on the interplay between the graph theory and systems theory, we revisit the analysis of reversible chemical reaction networks described by mass action kinetics by reformulating it using the graph knowledge of the underlying networks. Based on this formulation, we

  20. Chemical analysis and quality control of Ginkgo biloba leaves, extracts, and phytopharmaceuticals

    NARCIS (Netherlands)

    Beek, van T.A.; Montoro, P.

    2009-01-01

    The chemical analysis and quality control of Ginkgo leaves, extracts, phytopharmaceuticals and some herbal supplements is comprehensively reviewed. The review is an update of a similar, earlier review in this journal [T.A. van Beek, J. Chromatogr. A 967 (2002) 21¿55]. Since 2001 over 3000 papers on

  1. A methodology for chemical hazards analysis at nuclear fuels reprocessing plants

    International Nuclear Information System (INIS)

    The Savannah River Laboratory employs a formal methodology for chemical hazards analysis primarily for use in the risk assessment of its nuclear fuels reprocessing plants. The methodology combines interactive matrices for reactions of available materials, fault tree analysis, human factors, and extensive data banks on the operating history of the plants. Examples illustrate the methodology and a related data bank. 5 refs., 2 figs., 4 tabs

  2. PHYSICO-CHEMICAL ANALYSIS OF FRESH AND FERMENTED FRUIT JUICES PROBIOTICATED WITH LACTOBACILLUS CASEI

    OpenAIRE

    Bathal Vijaya Kumar; Mannepula Sreedharamurthy; Obulam Vijaya Sarathi Reddy

    2013-01-01

    The objective of this study was to find out the suitability of different fruit juices for probiotication by using Lactobacillus casei. Phyto-chemical analysis of different fruit juices (mango, sapota, grape and cantaloupe) were carried out using the standard methods. Carbohydrates, flavoniods, tannins, glycosides were present and alkaloids and saponins were absent in all the above fruit juices. Further analysis by TLC and DPPH methods indicated good antioxidant activity in all the fruit juice...

  3. Prediction of chemical, physical and sensory data from process parameters for frozen cod using multivariate analysis

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard; Jensen, H.S.; Bøknæs, Niels;

    1998-01-01

    varied systematically at two levels. The data obtained were evaluated using the multivariate methods, principal component analysis (PCA) and partial least squares (PLS) regression. The PCA models were used to identify which process parameters were actually most important for the quality of the frozen cod...... by ones and zeroes only. These results illustrate the application of multivariate analysis as an effective strategy for improving the quality of frozen fish products. (C) 1998 Society of Chemical Industry...

  4. 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. PMID:24633585

  5. Chemical and Sensory Evaluation of Bread Sold in Benue and Nasarawa States of Central Nigeria

    Directory of Open Access Journals (Sweden)

    M.O. Eke

    2013-05-01

    Full Text Available The proximate composition, vitamin and mineral contents as well as sensory properties of some selected brands of bread sold in Benue and Nasarawa States were determined using standard methods of analysis. Fresh loaves of six of the most popular brands of bread, three from Benue (Top choice, Ostrich, Tito and three from Nasarawa (Emziler, Canaan, Gods Promise, constituting samples A-F, were purchased from the respective bread factories within 4hrs of their production and used for the investigation. There were significant differences (p<0.05 in proximate composition with values ranging from 30.21-35.07% (moisture, 8.74-14.22% (crude protein, 2.00-8.10% (crude fat, 0.71-1.05% (crude fibre, 6.00-7.93% (ash and 35.81-48.18% (carbohydrate, thus showing compliance with Standards Organisation of Nigeria (SON specifications, especially in terms of moisture, protein, crude fibre and carbohydrate contents. The fat and ash contents of most of the bread samples were far above the specifications of 2.00% and 0.60% maximum, respectively. The mineral and vitamin contents were found to be quite high in all the bread samples. Sensory evaluation showed that sample C (Tito was the most preferred followed by sample E, A, B, D in that order. Sample F (Gods Promise was the least preferred in terms of sensory evaluation, but showed the highest compliance to SON specifications in terms of proximate composition. All the bread samples were found to be very rich in macro-and micro-nutrients.

  6. Chemical state of real surface of A2B6 type compounds

    International Nuclear Information System (INIS)

    Investigation results for chemical composition of real surface of zinc and cadmium chalcogenides (ZnSe, ZnTe, CdSe, CdTe) are generalized. Effect of impurities and oxide phase on adsorption and charging is considered. Determinating role of water in surface charging is shown. It is found that surface active centers are not screened by oxide phase

  7. Buoyancy-driven convection may switch between reactive states in three-dimensional chemical waves

    Czech Academy of Sciences Publication Activity Database

    Šebestíková, Lenka; Hauser, M. J. B.

    2012-01-01

    Roč. 85, č. 3 (2012), 036303. ISSN 1539-3755 R&D Projects: GA ČR GAP105/10/0919 Institutional research plan: CEZ:AV0Z20600510 Keywords : buoyancy-driven convection * chemical waves * iodate-arsenous acid reaction Subject RIV: BK - Fluid Dynamics Impact factor: 2.313, year: 2012

  8. The third United States-Japan meeting on the Toxicological Characterization of Environmental Chemicals.

    OpenAIRE

    Kurokawa, Y; Damstra, T

    1992-01-01

    This report summarizes the discussion of the Third U.S.-Japan Meeting on the Toxicological Characterization of Environmental Chemicals held under the auspices of the U.S.-Japan cooperative in research and development in science and technology. Recent data on the interrelationships between toxicity, cell proliferation, and carcinogenicity are presented.

  9. Application of hazard analysis critical control points (HACCP) to organic chemical contaminants in food.

    Science.gov (United States)

    Ropkins, K; Beck, A J

    2002-03-01

    Hazard Analysis Critical Control Points (HACCP) is a systematic approach to the identification, assessment, and control of hazards that was developed as an effective alternative to conventional end-point analysis to control food safety. It has been described as the most effective means of controlling foodborne diseases, and its application to the control of microbiological hazards has been accepted internationally. By contrast, relatively little has been reported relating to the potential use of HACCP, or HACCP-like procedures, to control chemical contaminants of food. This article presents an overview of the implementation of HACCP and discusses its application to the control of organic chemical contaminants in the food chain. Although this is likely to result in many of the advantages previously identified for microbiological HACCP, that is, more effective, efficient, and economical hazard management, a number of areas are identified that require further research and development. These include: (1) a need to refine the methods of chemical contaminant identification and risk assessment employed, (2) develop more cost-effective monitoring and control methods for routine chemical contaminant surveillance of food, and (3) improve the effectiveness of process optimization for the control of chemical contaminants in food. PMID:11934130

  10. Thermomechanical CSM analysis of a superheater tube in transient state

    Science.gov (United States)

    Taler, Dawid; Madejski, Paweł

    2011-12-01

    The paper presents a thermomechanical computational solid mechanics analysis (CSM) of a pipe "double omega", used in the steam superheaters in circulating fluidized bed (CFB) boilers. The complex cross-section shape of the "double omega" tubes requires more precise analysis in order to prevent from failure as a result of the excessive temperature and thermal stresses. The results have been obtained using the finite volume method for transient state of superheater. The calculation was carried out for the section of pipe made of low-alloy steel.

  11. Analysis of structural-phase state of monoaluminate calcium

    OpenAIRE

    Yu.A. Abzaev; Yu.S. Sarkisov; Kuznetsova, T. V.; S.V. Samchenko; A.A. Klopotov; V.D. Klopotov; D.S. Afanasyev

    2014-01-01

    Calcium aluminates have a decisive influence on the hydraulic activity of cement, in this regard, detailed study of them is an urgent task. The aim of this study is to determine the phase composition and detailed analysis of the structural-phase state of monoaluminate calcium by X-ray analysis. To research monoaluminate calcium powder diffractometer DRON4-07 was used, it has been modified to a digital signal processing. Shooting was performed on the copper radiation (Kα) scheme Bragg – Br...

  12. Elemental and Chemical State Analysis, XPS, for In-Situ Materials Analysis on Mars Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovation is the design of a monochromatic x-ray source to be used in a mission compatible XPS spectrometer. Existing x-ray sources for XPS are large, require...

  13. Elemental and Chemical State Analysis, XPS, for In-Situ Materials Analysis on Mars Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective in this project is the development of a monochromatic x-ray source for a small x-ray Photoelectron Spectrometer (XPS) suitable for NASA missions. This...

  14. Identification and Analysis of Transition and Metastable Markov States

    CERN Document Server

    Martini, Linda; Hummer, Gerhard; Buchete, Nicolae-Viorel; Rosta, Edina

    2016-01-01

    We present a new method that enables the identification and analysis of both transition and metastable conformational states from atomistic or coarse-grained molecular dynamics (MD) trajectories. Our algorithm is presented and studied by using both analytical and actual examples from MD simulations of the helix-forming peptide Ala5, and of a larger system, the epidermal growth factor receptor (EGFR) protein. In all cases, our method identifies automatically the corresponding transition states and metastable conformations in an optimal way, with the input of a set of relevant coordinates, by capturing accurately the intrinsic slowest relaxation rate. Our approach provides a general and easy to implement analysis method that provides unique insight into the molecular mechanism and the rare but crucial rate limiting conformational pathways occurring in complex dynamical systems such as molecular trajectories.

  15. Analysis of ground state in random bipartite matching

    CERN Document Server

    Shi, Gui-Yuan; Liao, Hao; Zhang, Yi-Cheng

    2015-01-01

    In human society, a lot of social phenomena can be concluded into a mathematical problem called the bipartite matching, one of the most well known model is the marriage problem proposed by Gale and Shapley. In this article, we try to find out some intrinsic properties of the ground state of this model and thus gain more insights and ideas about the matching problem. We apply Kuhn-Munkres Algorithm to find out the numerical ground state solution of the system. The simulation result proves the previous theoretical analysis using replica method. In the result, we also find out the amount of blocking pairs which can be regarded as a representative of the system stability. Furthermore, we discover that the connectivity in the bipartite matching problem has a great impact on the stability of the ground state, and the system will become more unstable if there were more connections between men and women.

  16. Market Analysis of non-structural chemical products within the Green Building trend

    OpenAIRE

    Soler Blasco, Antonia Elisa

    2014-01-01

    Green Building is a growing trend within the construction industry. HILTI AG, International Company that provides tools and consumables to the Construction Industry, and more concretely Business Unit Chemicals, noticed it from customers asking for information to get a Green Building Certification. Taking it as starting point, it has been developed the current Master Thesis with the aim to describe the Green Building Market in United States and Canada (the biggest markets) in order to know the...

  17. ANALYSIS OF CHEMICAL COMPOUNDS OF AGARWOOD OIL FROM DIFFERENT SPECIES BY GAS CHROMATOGRAPHY MASS SPECTROMETRY (GCMS)

    OpenAIRE

    Yumi Zuhanis Has-Yun Hashim; Nur Izzah Ismail; Phirdaous Abbas

    2014-01-01

    ABSTRACT: Agarwood oil is a highly prized type of oil due to its unique aroma. The oil is extracted from the fragrant resin found in the agarwood tree (trunk).  The unique aroma and quality of agarwood resin and oil are contributed by the presence of certain chemical compounds. In this work, analysis and comparison of the chemical compounds of agarwood oil from A. malaccensis, A. sub-integra and a mixture of both were conducted.  The essential oils were diluted in hexane (5%) prior to gas chr...

  18. Extracting chemical information from plane wave calculations by a 3D 'fuzzy atoms' analysis

    Science.gov (United States)

    Bakó, I.; Stirling, A.; Seitsonen, A. P.; Mayer, I.

    2013-03-01

    Bond order and valence indices have been calculated by the method of the three-dimensional 'fuzzy atoms' analysis, using the numerical molecular orbitals obtained from plane wave DFT calculations, i.e., without introducing any external atom-centered functions. Weight functions of both Hirshfeld and Becke types have been applied. The results are rather close to the similar 'fuzzy atoms' ones obtained by using atom-centered basis sets and agree well with the chemical expectations, stressing the power of the genuine chemical concepts.

  19. Impact analysis of different chemical pre-treatments on colour of apple discs during drying process

    OpenAIRE

    Magdić, D.; Lukinac, Jasmina; Jokić, Stela; Čačić-Kenjerić, F.; Bilić, M.; Velić, D.

    2009-01-01

    The main purpose of this study was to compare colour changes of chemically pre-treated dried apple discs. Changes were observed by chromameter in L*a*b* colour model by using Minolta chromameter CR-400 and by image analysis system in RGB colour model. Apple discs variety "Gold Rush" were pre-treated and dried in laboratory tray drier at drying temperature 70 °C and at airflow velocity of 1.5 ms-1. Different chemical pre-treatments were applied on apple discs (dipping in 0.5% ascorbic acid sol...

  20. Sampling and chemical analysis in environmental samples around Nuclear Power Plants and some environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Woo; Han, Man Jung; Cho, Seong Won; Cho, Hong Jun; Oh, Hyeon Kyun; Lee, Jeong Min; Chang, Jae Sook [KORTIC, Taejon (Korea, Republic of)

    2002-12-15

    Twelve kinds of environmental samples such as soil, seawater, underground water, etc. around Nuclear Power Plants(NPPs) were collected. Tritium chemical analysis was tried for the samples of rain water, pine-needle, air, seawater, underground water, chinese cabbage, a grain of rice and milk sampled around NPPs, and surface seawater and rain water sampled over the country. Strontium in the soil that sere sampled at 60 point of district in Korea were analyzed. Tritium were sampled at 60 point of district in Korea were analyzed. Tritium were analyzed in 21 samples of surface seawater around the Korea peninsular that were supplied from KFRDI(National Fisheries Research and Development Institute). Sampling and chemical analysis environmental samples around Kori, Woolsung, Youngkwang, Wooljin Npps and Taeduk science town for tritium and strontium analysis was managed according to plans. Succeed to KINS after all samples were tried.

  1. Gait identification by using spectrum analysis on state space reconstruction

    OpenAIRE

    Ruiz Vegas, Francisco Javier; Samà Monsonís, Albert; Pérez López, Carlos; Català Mallofré, Andreu

    2011-01-01

    This paper describes a method for identifying a person while walking by means of a triaxial accelerometer attached to the waist. Human gait is considered as a dynamical system whose attractor is reconstructed by time delay vectors. A Spectral Analysis on the state space reconstruction is used to characterize the attractor. Parameters involved in the reconstruction and characterization process are evaluated to examine the effect in gait identification. The method is tested in...

  2. Gait recognition by using spectrum analysis on state space reconstruction

    OpenAIRE

    Samà Monsonís, Albert; Ruiz Vegas, Francisco Javier; Pérez López, Carlos; Català Mallofré, Andreu

    2011-01-01

    This paper describes a method for identifying a person while walking by means of a triaxial accelerometer attached to the waist. Human gait is considered as a dynamical system whose attractor is reconstructed by time delay vectors. A Spectral Analysis on the state space reconstruction is used to characterize the attractor. The method is compared to other common methods used in gait recognition tasks through a preliminary test.

  3. Music Data Analysis: A State-of-the-art Survey

    OpenAIRE

    Gupta, Shubhanshu

    2014-01-01

    Music accounts for a significant chunk of interest among various online activities. This is reflected by wide array of alternatives offered in music related web/mobile apps, information portals, featuring millions of artists, songs and events attracting user activity at similar scale. Availability of large scale structured and unstructured data has attracted similar level of attention by data science community. This paper attempts to offer current state-of-the-art in music related analysis. V...

  4. United States Marine Corps aerial refueling requirements analysis

    OpenAIRE

    Gates, William R.; McCarthy, Mitchell J.

    2000-01-01

    The United States Marine Corps (USMC) currently operates a fleet of KC130 aerial refueling tanker aircraft. This paper uses queuing and simulation models to examine the USMC KC130 tanker requirement, contrasts the results and explores the budgetary implications of alternative fleet requirements. This analysis finds that queuing models don't account for some of the complexities of aerial refueling operations. Therefore, queuing models may miscalculate the KC130 requirement. Simulation mode...

  5. 我国煤化工发展分析%China Coal Chemical Industry Development Analysis

    Institute of Scientific and Technical Information of China (English)

    李志龙; 陈明

    2011-01-01

    The paper stated the characteristics of the coal chemical and analyzed the challenges and opportunities of the coal chemical development in China.The coal chemical must stick to the principle of being in proportion and in order.We need pay close attenton to international markets of crude oil and chemical products and analyse carefully the market competitiveness of coal-base products.Actively promote coal production enterprises and chemical enterprise power-and-power union.%文章阐述了新型煤化工的特点,分析了中国发展煤化工面临的挑战和机遇。发展煤化工必须坚持适度、有序的原则,综合考虑社会投入,高度关注国际油价和石化产品市场,认真分析市场竞争力,积极推动煤炭生产企业与煤化工企业强强联合。

  6. Climate and bioclimate analysis of Ondo State, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Omonijo, Akinyemi Gabriel [Freiburg Univ. (Germany). Meteorological Inst.; Rufus Giwa Polytechnic, Owo (Nigeria). Dept. of Agricultural Technology; Matzarakis, Andreas [Freiburg Univ. (Germany). Meteorological Inst.

    2011-10-15

    Most of the previous analyses of climate of Nigeria, particularly Ondo State have been for agricultural use. They have little or no application for biometeorological purposes. This paper examines and analyse the climate of Ondo State, Nigeria with respect to biometeorological parameters based on air temperature, relative humidity, wind speed, solar radiation and rainfall from 1998 to 2008. It assesses the previous methods of climatic analysis with respect to biometeorology. It then use complete heat budget model approach and RayMan model as analytical tool to calculate physiologically equivalent temperature (PET) in order to define thermo-physiological thresholds and classify biometeorological parameters in Ondo State. Detailed analysis of thermal comfort patterns indicate that there are marked spatial and seasonal variations in thermal comfort over the study area. The result shows three different grade of physiological stress over the two zones of Ondo State, that is the humid forest zone and derived savannah zone. The study recommends incorporation of atmospheric environmental parameters into health management systems of the country in order to achieve the Millennium Development Goals (MDG) in health sector. (orig.)

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

    International Nuclear Information System (INIS)

    Graphical abstract: Direct and humidity independent mass spectrometry analysis of gas phase chemicals could be achieved via ambient proton transfer ionization, ion intensity was found to be stable with humidity ranged from ∼10% to ∼100%. - Highlights: • A humidity independent mass spectrometric method for gas phase samples analysis. • A universal and good sensitivity method. • The method can real time identify plant released raw chemicals. - Abstract: 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

  8. Applying Chemical Imaging Analysis to Improve Our Understanding of Cold Cloud Formation

    Science.gov (United States)

    Laskin, A.; Knopf, D. A.; Wang, B.; Alpert, P. A.; Roedel, T.; Gilles, M. K.; Moffet, R.; Tivanski, A.

    2012-12-01

    The impact that atmospheric ice nucleation has on the global radiation budget is one of the least understood problems in atmospheric sciences. This is in part due to the incomplete understanding of various ice nucleation pathways that lead to ice crystal formation from pre-existing aerosol particles. Studies investigating the ice nucleation propensity of laboratory generated particles indicate that individual particle types are highly selective in their ice nucleating efficiency. This description of heterogeneous ice nucleation would present a challenge when applying to the atmosphere which contains a complex mixture of particles. Here, we employ a combination of micro-spectroscopic and optical single particle analytical methods to relate particle physical and chemical properties with observed water uptake and ice nucleation. Field-collected particles from urban environments impacted by anthropogenic and marine emissions and aging processes are investigated. Single particle characterization is provided by computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). A particle-on-substrate approach coupled to a vapor controlled cooling-stage and a microscope system is applied to determine the onsets of water uptake and ice nucleation including immersion freezing and deposition ice nucleation as a function of temperature (T) as low as 200 K and relative humidity (RH) up to water saturation. We observe for urban aerosol particles that for T > 230 K the oxidation level affects initial water uptake and that subsequent immersion freezing depends on particle mixing state, e.g. by the presence of insoluble particles. For T air parcel.

  9. Observations on the morphology and chemical analysis of medullary granules in chinchilla hair. Research letters

    Energy Technology Data Exchange (ETDEWEB)

    Keogh, H.J. (South African Inst. for Medical Research, Johannesburg); Haylett, T. (Council for Scientific and Industrial Research, Pretoria (South Africa). National Chemical Research Lab.)

    1983-02-01

    The ultrastructure of the medullary granules of white and grey chinchilla hair was investigated by scanning electron microscopy and chemical analysis in an attempt to clarify their structure and function. Atomic absorption spectroscopy and amino acid analysis showed them to be composed of melanin. The sample preparation for scanning electron microscopy is discussed. The metal content was qualitatively established by X-ray fluorescence spectrometry and quantitatively determined on a Varian Techtron model AAs atomic absorption spectrophotometer. Amino acid analysis of the granule, was carried out on a Beckman 121 amino acid analyser. Information is provided on the amino acid composition of the medullary granules as well as its metal content.

  10. Observations on the morphology and chemical analysis of medullary granules in chinchilla hair

    International Nuclear Information System (INIS)

    The ultrastructure of the medullary granules of white and grey chinchilla hair was investigated by scanning electron microscopy and chemical analysis in an attempt to clarify their structure and function. Atomic absorption spectroscopy and amino acid analysis showed them to be composed of melanin. The sample preparation for scanning electron microscopy is discussed. The metal content was qualitatively established by X-ray fluorescence spectrometry and quantitatively determined on a Varian Techtron model AAs atomic absorption spectrophotometer. Amino acid analysis of the granule, was carried out on a Beckman 121 amino acid analyser. Information is provided on the amino acid composition of the medullary granules as well as its metal content

  11. Dynamics of transient metastable states in mixtures under coupled phase ordering and chemical demixing

    OpenAIRE

    Soulé, Ezequiel R.; Rey, Alejandro D.

    2013-01-01

    We present theory and simulation of simultaneous chemical demixing and phase ordering in a polymer-liquid crystal mixture in conditions where isotropic-isotropic phase separation is metastable with respect to isotropic-nematic phase transition. In the case the mechanism is nucleation and growth, it is found that mesophase growth proceeds by a transient metastable phase that surround the ordered phase, and whose lifetime is a function of the ratio of diffusional to orientational mobilities. In...

  12. Association between Six Environmental Chemicals and Lung Cancer Incidence in the United States

    OpenAIRE

    Juhua Luo; Michael Hendryx; Alan Ducatman

    2011-01-01

    Background. An increased risk of lung cancer has been observed at exposure to certain industrial chemicals in occupational settings; however, less is known about their carcinogenic potential to the general population when those agents are released into the environment. Methods. We used the Toxics Release Inventory (TRI) database and Surveillance, Epidemiology, and End Results (SEER) data to conduct an ecological study at the county level. We used multiple linear regression to assess the assoc...

  13. Sentence-processing in echo state networks: a qualitative analysis by finite state machine extraction

    Science.gov (United States)

    Frank, Stefan L.; Jacobsson, Henrik

    2010-06-01

    It has been shown that the ability of echo state networks (ESNs) to generalise in a sentence-processing task can be increased by adjusting their input connection weights to the training data. We present a qualitative analysis of the effect of such weight adjustment on an ESN that is trained to perform the next-word prediction task. Our analysis makes use of CrySSMEx, an algorithm for extracting finite state machines (FSMs) from the data about the inputs, internal states, and outputs of recurrent neural networks that process symbol sequences. We find that the ESN with adjusted input weights yields a concise and comprehensible FSM. In contrast, the standard ESN, which shows poor generalisation, results in a massive and complex FSM. The extracted FSMs show how the two networks differ behaviourally. Moreover, poor generalisation is shown to correspond to a highly fragmented quantisation of the network's state space. Such findings indicate that CrySSMEx can be a useful tool for analysing ESN sentence processing.

  14. Comparisons of classical and Wigner sampling of transition state energy levels for quasiclassical trajectory chemical dynamics simulations

    International Nuclear Information System (INIS)

    Quasiclassical trajectory calculations are compared, with classical and Wigner sampling of transition state (TS) energy levels, for C2H5F≠→HF+C2H4 product energy partitioning and [Cl···CH3···Cl]- central barrier dynamics. The calculations with Wigner sampling are reported here for comparison with the previously reported calculations with classical sampling [Y. J. Cho et al., J. Chem. Phys. 96, 8275 (1992); L. Sun and W. L. Hase, J. Chem. Phys. 121, 8831 (2004)]. The C2H5F≠ calculations were performed with direct dynamics at the MP2/6-31G* level of theory. Classical and Wigner sampling give post-transition state dynamics, for these two chemical systems, which are the same within statistical uncertainties. This is a result of important equivalences in these two sampling methods for selecting initial conditions at a TS. In contrast, classical and Wigner sampling often give different photodissociation dynamics [R. Schinke, J. Phys. Chem. 92, 3195 (1988)]. Here the sampling is performed for a vibrational state of the ground electronic state potential energy surface (PES), which is then projected onto the excited electronic state's PES. Differences between the ground and the excited PESs may give rise to substantially different excitations of the vibrational and dissociative coordinates on the excited state PES by classical and Wigner sampling, resulting in different photodissociation dynamics.

  15. Physico Chemical Analysis of Sapota (Manilkara zapota Coated by Edible Aloe Vera Gel

    Directory of Open Access Journals (Sweden)

    N. Padmaja

    2015-03-01

    Full Text Available The physical and chemical characteristics of the fruit have immense significance as they ultimately affect the quality of processed productsprepared from them. Over ripening of Sapota (Manilkara zapota fruits at the post-harvest stage usually results in dramatic decline in quality.In the present study, physico chemical analysis (which includes Weight loss, Colour, Texture, TSS, pH, TA and Ascorbic acid content ofedible Aloe vera gel coated Sapota fruits packed in LDPE and stored at 15 ± 2? were studied at regular intervals of 5 days i.e., 0th,5th, 10th,15thand 20th days. The dip treatment of Aloe vera gel coating 1:2, 7 minutes had best retained the physico chemical characteristics than the othertreatments performed and was found to be the most effective treatment in maintaining the fruit quality attributes along with the shelf lifeextension of about 20 days.

  16. Low Cost Long Distance Detector for Explosives and Chemical Analysis by IEC Application

    Directory of Open Access Journals (Sweden)

    George H. Miley

    2005-01-01

    Full Text Available A radiation source for detecting specific chemicals at several meter distances even behind walls, car doors or other barriers is the application of Million electron Volts (MeV neutrons from nuclear fusion reactions at such low intensities to avoid any danger for human bodies. The chemical analysis consists in the neutron activation of nuclei emitting then gamma radiation of lines very specific for the excited nuclei. The neutron generation by the Inertial Electrostatic Confinement (IEC had been developed to a level where very low cost neutron generators in mass production may be developed with a power supply from a normal AC plug-in or a battery. For specific chemicals e.g. the ratio of nitrogen against other elements used in all explosives, the selection of few specific gamma lines for the detectors may be of sufficiently low cost in the case of mass production.

  17. Development and Analysis of Group Contribution Plus Models for Property Prediction of Organic Chemical Systems

    DEFF Research Database (Denmark)

    Mustaffa, Azizul Azri

    and further development of the GCPlus approach for predicting mixture properties to be called the UNIFAC-CI model. The contributions of this work include an analysis of the developed Original UNIFAC-CI model in order to investigate why the model does not perform as well as the reference UNIFAC model......Prediction of properties is important in chemical process-product design. Reliable property models are needed for increasingly complex and wider range of chemicals. Group-contribution methods provide useful tool but there is a need to validate them and improve their accuracy when complex chemicals...... are present in the mixtures. In accordance with that, a combined group-contribution and atom connectivity approach that is able to extend the application range of property models has been developed for mixture properties. This so-called Group-ContributionPlus (GCPlus) approach is a hybrid model which...

  18. Clinical-Functional State of Respiratory Organs of Chemical Production Workers

    Directory of Open Access Journals (Sweden)

    Sabit S. Shorin

    2014-05-01

    Full Text Available The clinical-functional research has allowed to identify the functional state of respiratory organs of production workers. The pathology is formed through stages (healthy –unhealthy individuals.

  19. Physico-chemical characteristics of honey produced by Apis mellifera in the Picos region, state of Piauí, Brazil

    Directory of Open Access Journals (Sweden)

    Geni da Silva Sodré

    2011-08-01

    Full Text Available The objectives of this research were to determine physico-chemical characteristics of 1,758 Apis mellifera L. honey samples produced by in the productive pole of Picos, state of Piauí, to understand, based on these characteristics, how they are grouped and to determine the percentage of honey that fit the specifications determined by Brazilian legislation. Thirty-five honey samples were collected directly from beekeepers for determination of total sugars, reducing sugars, apparent sucrose, humidity, diastase activity, hydroxymethylfurfural (HMF, protein, ash, pH, acidity, formol index, electrical conductivity, viscosity and color. Mean values of each one of the analyzed physico-chemical parameters are within the limits established by the current Brazilian legislation, but it was verified for apparent sacarosis, diastase activity and HMF, values different from the established ones. Protein and HMF were the traits that contributed most for group formation.

  20. QM/MM Analysis of Transition States and Transition State Analogues in Metalloenzymes.

    Science.gov (United States)

    Roston, D; Cui, Q

    2016-01-01

    Enzymology is approaching an era where many problems can benefit from computational studies. While ample challenges remain in quantitatively predicting behavior for many enzyme systems, the insights that often come from computations are an important asset for the enzymology community. Here we provide a primer for enzymologists on the types of calculations that are most useful for mechanistic problems in enzymology. In particular, we emphasize the integration of models that range from small active-site motifs to fully solvated enzyme systems for cross-validation and dissection of specific contributions from the enzyme environment. We then use a case study of the enzyme alkaline phosphatase to illustrate specific application of the methods. The case study involves examination of the binding modes of putative transition state analogues (tungstate and vanadate) to the enzyme. The computations predict covalent binding of these ions to the enzymatic nucleophile and that they adopt the trigonal bipyramidal geometry of the expected transition state. By comparing these structures with transition states found through free energy simulations, we assess the degree to which the transition state analogues mimic the true transition states. Technical issues worth treating with care as well as several remaining challenges to quantitative analysis of metalloenzymes are also highlighted during the discussion. PMID:27498640

  1. Combined Micro-chemical and Micro-structural Analysis of New Minerals Representing Extreme Conditions

    Science.gov (United States)

    Ma, C.; Tschauner, O. D.

    2015-12-01

    Recent improvements in micro-chemical analysis in combination with novel tools for micrometer-scale structural analysis of minerals from synchrotron X-ray diffraction open a pathway towards studies of mineral paragenesis that were previously not or barely accessible. Often mineral assemblies that represent extreme conditions also pose extreme challenges to analysis: very small size scale, complex matrix, minor amounts of material. Examples of such extreme, but also quite relevant environments are: a) High pressure shock-metamorphic minerals in meteorites and terrestrial impact sites, b) inclusions in diamonds from the deep mantle, c) ultrarefractory phases in Ca-Al-inlcusions from the solar nebula, d) presolar condensates. We show how a combination of synchrotron-based structural and semi-quantitative chemical techniques, with electron-microscopy based high-resolution imaging and fully quantitative chemical analysis and qualitative structural identification establish a powerful tool for discovery and characterization of important and interesting new minerals on micron- to submicron size scale.

  2. USE OF AMAZONIAN SPECIES FOR AGING DISTILLED BEVERAGES: PHYSICAL AND CHEMICAL WOOD ANALYSIS

    Directory of Open Access Journals (Sweden)

    Jonnys Paz Castro

    2015-06-01

    Full Text Available The process of storing liquor in wooden barrels is a practice that aims to improve the sensory characteristics, such as color, aroma and flavor, of the beverage. The quality of the liquor stored in these barrels depends on wood characteristics such as density, permeability, chemical composition, anatomy, besides the wood heat treatment used to fabricate the barrels. Brazil has a great diversity of forests, mainly in the north, in the Amazon. This region is home to thousands of tree species, but is limited to the use of only a few native species to store liquors. The objective of this study was to determine some of the physical and chemical characteristics for four Amazon wood species. The results obtained in this study will be compared with others from woods that are traditionally used for liquor storage. The species studied were angelim-pedra (Hymenolobium petraeum Ducke cumarurana (Dipteryx polyphylla (Huber Ducke, jatobá (Hymenaea courbaril L. and louro-vermelho (Nectandra rubra (Mez CK Allen. The trees were collected from Precious Woods Amazon Company forest management area, in Silves, Amazonas. Analyzes such as: concentration of extractives, lignin amount, percentage of minerals (ash and tannin content, density, elemental analysis (CHNS-O and thermal analysis were done. It was observed that the chemical composition (lignin, holocellulose and elemental analysis (percentage of C, H, N and O of the woods have significant differences. The jatobá wood presented higher tannin content, and in the thermal analysis, was that which had the lowest mass loss.

  3. Chemical and physical analysis of core materials for advanced high temperature reactors with process heat applications

    International Nuclear Information System (INIS)

    Various chemical and physical methods for the analysis of structural materials have been developed in the research programmes for advanced high temperature reactors. These methods are discussed using as examples the structural materials of the reactor core - the fuel elements consisting of coated particles in a graphite matrix and the structural graphite. Emphasis is given to the methods of chemical analysis. The composition of fuel kernels is investigated using chemical analysis methods to determine the heavy metals content (uranium, plutonium, thorium and metallic impurity elements) and the amount of non-metallic constituents. The properties of the pyrocarbon and silicon carbide coatings of fuel elements are investigated using specially developed physiochemical methods. Regarding the irradiation behaviour of coated particles and fuel elements, methods have been developed for examining specimens in hot cells following exposures under reactor operating conditions, to supplement the measurements of in-reactor performance. For the structural graphite, the determination of impurities is important because certain impurities may cause pitting corrosion during irradiation. The localized analysis of very low impurity concentrations is carried out using spectrochemical d.c. arc excitation, local laser and inductively coupled plasma methods. (orig.)

  4. Effect of molecular weight on radiation chemical degradation yield of chain scission of γ-irradiated chitosan in solid state and in aqueous solution

    International Nuclear Information System (INIS)

    Chitosan A1, A2 and A3 with molecular weight of 471, 207 and 100 kDa respectively, produced from squid pen chitin was degraded by gamma rays in the solid state and in aqueous solution with various doses in air at ambient temperature. Effect of molecular weight on radiation chemical degradation yield of chain scission and degradation rate constants of γ-irradiated chitosan in solid state and in aqueous solution was investigated. The radiation chemical degradation yield G(s) and degradation rate values were calculated. The molecular weight changes were monitored by capillary viscometry method and the chemical structure changes were followed by UV analysis. The results showed that, the degradation of chitosan was faster in solution, than in solid state. The values of G(s) in solid state and in aqueous solution were respectively 1.1×10−8 mol/J and 0.074×10−7 mol/J for A1, 4.42×10−8 mol/J and 0.28×10−7 mol/J for A2 and 6.08×10−8 mol/J and 0.38×10−7 mol/J for A3. Degradation rate constants values ranged from 0.41×10−5 to 2.1×10−5 kGy−1 in solid state, whereas in solution they ranged from 13×10−5 to 68×10−5 kGy−1. The chitosan A3 was more sensitive to radiolysis than A1 and A2. The chain scission yield, G(s) and degradation rate constants seems to be greatly influenced by the initial molecular weight of the chitosan. Structural changes in irradiated chitosan are revealed by the apparition of absorption peaks at 261 and 295 nm, which could be attributed to the formation of carbonyl groups. In both conditions the peak intensity was higher in chitosan A3 than in A1 and A2, the oxidative products decreased with increasing molecular weight of chitosan. - Highlights: ► We investigated the effects of MW on G(s) value of γ-irradiated chitosan in solid and aqueous state. ► Chitosan with low molecular weight was more sensitive to radiolysis than high molecular weight. ► G(s) value and degradation rate seems to be greatly influenced by the

  5. DPABI: Data Processing & Analysis for (Resting-State) Brain Imaging.

    Science.gov (United States)

    Yan, Chao-Gan; Wang, Xin-Di; Zuo, Xi-Nian; Zang, Yu-Feng

    2016-07-01

    Brain imaging efforts are being increasingly devoted to decode the functioning of the human brain. Among neuroimaging techniques, resting-state fMRI (R-fMRI) is currently expanding exponentially. Beyond the general neuroimaging analysis packages (e.g., SPM, AFNI and FSL), REST and DPARSF were developed to meet the increasing need of user-friendly toolboxes for R-fMRI data processing. To address recently identified methodological challenges of R-fMRI, we introduce the newly developed toolbox, DPABI, which was evolved from REST and DPARSF. DPABI incorporates recent research advances on head motion control and measurement standardization, thus allowing users to evaluate results using stringent control strategies. DPABI also emphasizes test-retest reliability and quality control of data processing. Furthermore, DPABI provides a user-friendly pipeline analysis toolkit for rat/monkey R-fMRI data analysis to reflect the rapid advances in animal imaging. In addition, DPABI includes preprocessing modules for task-based fMRI, voxel-based morphometry analysis, statistical analysis and results viewing. DPABI is designed to make data analysis require fewer manual operations, be less time-consuming, have a lower skill requirement, a smaller risk of inadvertent mistakes, and be more comparable across studies. We anticipate this open-source toolbox will assist novices and expert users alike and continue to support advancing R-fMRI methodology and its application to clinical translational studies. PMID:27075850

  6. Preliminary Analysis of a Fully Solid State Magnetocaloric Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [ORNL

    2016-01-01

    Magnetocaloric refrigeration is an alternative refrigeration technology with significant potential energy savings compared to conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. In this paper, we propose an alternative mechanism for heat transfer between the AMR and the heat source/sink. High-conductivity moving rods/sheets (e.g. copper, brass, iron, graphite, aluminum or composite structures from these) are utilized instead of heat transfer fluid significantly enhancing the heat transfer rate hence cooling/heating capacity. A one-dimensional model is developed to study the solid state AMR. In this model, the heat exchange between the solid-solid interfaces is modeled via a contact conductance, which depends on the interface apparent pressure, material hardness, thermal conductivity, surface roughness, surface slope between the interfaces, and material filled in the gap between the interfaces. Due to the tremendous impact of the heat exchange on the AMR cycle performance, a sensitivity analysis is conducted employing a response surface method, in which the apparent pressure, effective surface roughness and grease thermal conductivity are the uncertainty factors. COP and refrigeration capacity are presented as the response in the sensitivity analysis to reveal the important factors influencing the fully solid state AMR and optimize the solid state AMR efficiency. The performances of fully solid state AMR and traditional AMR are also compared and discussed in present work. The results of this study will provide general guidelines for designing high performance solid state AMR systems.

  7. A chemically modified [alpha]-amylase with a molten-globule state has entropically driven enhanced thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Khawar Sohail; Poljak, Anne; De Francisci, Davide; Guerriero, Gea; Pilak, Oliver; Burg, Dominic; Raftery, Mark J.; Parkin, Don M.; Trewhella, Jill; Cavicchioli, Ricardo (Sydney); (New South)

    2010-11-15

    The thermostability properties of TAA were investigated by chemically modifying carboxyl groups on the surface of the enzyme with AMEs. The TAA{sub MOD} exhibited a 200% improvement in starch-hydrolyzing productivity at 60 C. By studying the kinetic, thermodynamic and biophysical properties, we found that TAA{sub MOD} had formed a thermostable, MG state, in which the unfolding of the tertiary structure preceded that of the secondary structure by at least 20 C. The X-ray crystal structure of TAA{sub MOD} revealed no new permanent interactions (electrostatic or other) resulting from the modification. By deriving thermodynamic activation parameters of TAA{sub MOD}, we rationalised that thermostabilisation have been caused by a decrease in the entropy of the transition state, rather than being enthalpically driven. Far-UV CD shows that the origin of decreased entropy may have arisen from a higher helical content of TAA{sub MOD}. This study provides new insight into the intriguing properties of an MG state resulting from the chemical modification of TAA.

  8. Clarifying the chemical state of additives in membranes for polymer electrolyte fuel cells by X-ray absorption fine structure

    Science.gov (United States)

    Tanuma, Toshihiro; Itoh, Takanori

    2016-02-01

    Cerium and manganese compounds are used in the membrane for polymer electrolyte fuel cells (PEFCs) as radical scavengers to mitigate chemical degradation of the membrane. The chemical states of cerium and manganese in the membrane were investigated using a fluorescence X-ray absorption fine structure (XAFS) technique. Membrane electrode assemblies (MEAs) were subjected to open circuit voltage (OCV) condition, under which hydroxyl radicals attack the membrane; a shift in absorption energy in X-ray absorption near edge structure (XANES) spectra was compared between Ce- and Mn-containing membranes before and after OCV testing. In the case of the Ce-containing MEA, there was no significant difference in XANES spectra before and after OCV testing, whereas in the case of the Mn-containing MEA, there was an obvious shift in XANES absorption energy after OCV testing, indicating that Mn atoms with higher valence state than 2+ exist in the membrane after OCV testing. This can be attributed to the difference in the rate of reduction; the reaction of Ce4+ with ·OOH is much faster than that of Mn3+ with ·OOH, leaving some of the Mn atoms with higher valence state. It was confirmed that cerium and manganese redox couples reduced the attack from radicals, mitigating membrane degradation.

  9. Analysis of changes in the chemical composition of the blast furnace coke at high temperatures

    Directory of Open Access Journals (Sweden)

    A. Konstanciak

    2012-12-01

    Full Text Available Purpose: The main purpose of this paper was to analyze the behavior of coke in the blast furnace. The analysis of changes in chemical composition of coke due to impact of inert gas and air at different temperatures was made. The impact of the application of the thermoabrasion coefficient on the porosity of coke was also analyzed.Design/methodology/approach: By applying the Computer Thermochemical Database of the TERMO system (REAKTOR1 and REAKTOR3 three groups of substances can be distinguished. The chemical composition of blast furnace coke and the results of calculations of changes of chemical composition of coke heat treated under certain conditions were compared. The structural studies of these materials were presented.Findings: The results of the analysis of ash produced from one of Polish cokes was taken for consideration. This is not the average composition of Polish coke ashes, nevertheless it is representative of most commonly occurring chemical compositions.Practical implications: Thanks to the thermochemical calculations it is possible to predict ash composition after the treatment in a blast furnace. Those information was crucial and had an actual impact on determining the coke quality.Originality/value: Presentation of the analytical methods which, according to author, can be very useful to evaluate and identify the heat treatment for blast furnaces cokes. The research pursued represents part of a larger project carried out within the framework of Department Extraction and Recycling of Metals, Czestochowa University of Technology.

  10. Phthalic Acid Chemical Probes Synthesized for Protein-Protein Interaction Analysis

    Directory of Open Access Journals (Sweden)

    Chin-Jen Wu

    2013-06-01

    Full Text Available Plasticizers are additives that are used to increase the flexibility of plastic during manufacturing. However, in injection molding processes, plasticizers cannot be generated with monomers because they can peel off from the plastics into the surrounding environment, water, or food, or become attached to skin. Among the various plasticizers that are used, 1,2-benzenedicarboxylic acid (phthalic acid is a typical precursor to generate phthalates. In addition, phthalic acid is a metabolite of diethylhexyl phthalate (DEHP. According to Gene_Ontology gene/protein database, phthalates can cause genital diseases, cardiotoxicity, hepatotoxicity, nephrotoxicity, etc. In this study, a silanized linker (3-aminopropyl triethoxyslane, APTES was deposited on silicon dioxides (SiO2 particles and phthalate chemical probes were manufactured from phthalic acid and APTES–SiO2. These probes could be used for detecting proteins that targeted phthalic acid and for protein-protein interactions. The phthalic acid chemical probes we produced were incubated with epithelioid cell lysates of normal rat kidney (NRK-52E cells to detect the interactions between phthalic acid and NRK-52E extracted proteins. These chemical probes interacted with a number of chaperones such as protein disulfide-isomerase A6, heat shock proteins, and Serpin H1. Ingenuity Pathways Analysis (IPA software showed that these chemical probes were a practical technique for protein-protein interaction analysis.

  11. Analysis of pharmaceutical pellets: An approach using near-infrared chemical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sabin, Guilherme P.; Breitkreitz, Marcia C.; Souza, Andre M. de [Institute of Chemistry, University of Campinas, P.O. Box 6154, 13084-971 Campinas, SP (Brazil); Fonseca, Patricia da; Calefe, Lupercio; Moffa, Mario [Zelus Servicos para Industria Farmaceutica Ltda., Av. Professor Lineu Prestes n. 2242, Sao Paulo, SP (Brazil); Poppi, Ronei J., E-mail: ronei@iqm.unicamp.br [Institute of Chemistry, University of Campinas, P.O. Box 6154, 13084-971 Campinas, SP (Brazil)

    2011-11-07

    Highlights: {yields} Near-Infrared Chemical Imaging was used for pellets analysis. {yields} Distribution of the components throughout the coatings layers and core of the pellets was estimated. {yields} Classical Least Squares (CLS) was used for calculation of the concentration maps. - Abstract: Pharmaceutical pellets are spherical or nearly spherical multi-unit dosage forms designed to optimize pharmacokinetics and pharmacodynamics features of drug release. The distribution of the pharmaceutical ingredients in the layers and core is a very important parameter for appropriate drug release, especially for pellets manufactured by the process of layer gain. Physical aspects of the sample are normally evaluated by Scanning Electron Microscopy (SEM), but it is in many cases unsuitable to provide conclusive chemical information about the distribution of the pharmaceutical ingredients in both layers and core. On the other hand, methods based on spectroscopic imaging can be very promising for this purpose. In this work, a Near-Infrared Chemical Imaging (NIR-CI) method was developed and applied to the analysis of diclophenac sodium pellets. Since all the compounds present in the sample were known in advance, Classical Least Squares (CLS) was used for calculations. The results have shown that the method was capable of providing chemical information about the distribution of the active ingredient and excipients in the core and coating layers and therefore can be complementary to SEM for the pharmaceutical development of pellets.

  12. Analysis of pharmaceutical pellets: An approach using near-infrared chemical imaging

    International Nuclear Information System (INIS)

    Highlights: → Near-Infrared Chemical Imaging was used for pellets analysis. → Distribution of the components throughout the coatings layers and core of the pellets was estimated. → Classical Least Squares (CLS) was used for calculation of the concentration maps. - Abstract: Pharmaceutical pellets are spherical or nearly spherical multi-unit dosage forms designed to optimize pharmacokinetics and pharmacodynamics features of drug release. The distribution of the pharmaceutical ingredients in the layers and core is a very important parameter for appropriate drug release, especially for pellets manufactured by the process of layer gain. Physical aspects of the sample are normally evaluated by Scanning Electron Microscopy (SEM), but it is in many cases unsuitable to provide conclusive chemical information about the distribution of the pharmaceutical ingredients in both layers and core. On the other hand, methods based on spectroscopic imaging can be very promising for this purpose. In this work, a Near-Infrared Chemical Imaging (NIR-CI) method was developed and applied to the analysis of diclophenac sodium pellets. Since all the compounds present in the sample were known in advance, Classical Least Squares (CLS) was used for calculations. The results have shown that the method was capable of providing chemical information about the distribution of the active ingredient and excipients in the core and coating layers and therefore can be complementary to SEM for the pharmaceutical development of pellets.

  13. State and prospects of rehabilitation persons with radiation and chemical injuries in Tatarstan Republic

    International Nuclear Information System (INIS)

    Preliminary data on complex investigation of 442 patients participating in liquidation of consequences of the Ch NPP accident, and their children, living at the territory of the Tatarstan Republic are presented. The existing system of rehabilitation of persons, injured in rehabilitation of persons, injured in the course of emergency situations, as well as the prospects of its development are considered. Special attention is paid to the program on rehabilitation of the Ch NPP accident and other radiation accident consequences liquidators, The actuality of the program on training and upgrading qualification of medical personnel and social workers, engaged in medical and social-labour rehabilitation of persons with radiation-chemical injuries is noted

  14. State-trace analysis: dissociable processes in a connectionist network?

    Science.gov (United States)

    Yeates, Fayme; Wills, Andy J; Jones, Fergal W; McLaren, Ian P L

    2015-07-01

    Some argue the common practice of inferring multiple processes or systems from a dissociation is flawed (Dunn, 2003). One proposed solution is state-trace analysis (Bamber, 1979), which involves plotting, across two or more conditions of interest, performance measured by either two dependent variables, or two conditions of the same dependent measure. The resulting analysis is considered to provide evidence that either (a) a single process underlies performance (one function is produced) or (b) there is evidence for more than one process (more than one function is produced). This article reports simulations using the simple recurrent network (SRN; Elman, 1990) in which changes to the learning rate produced state-trace plots with multiple functions. We also report simulations using a single-layer error-correcting network that generate plots with a single function. We argue that the presence of different functions on a state-trace plot does not necessarily support a dual-system account, at least as typically defined (e.g. two separate autonomous systems competing to control responding); it can also indicate variation in a single parameter within theories generally considered to be single-system accounts. PMID:25307272

  15. Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

    2014-06-09

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  16. Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen

    International Nuclear Information System (INIS)

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  17. Resonance Raman spectroscopy with chemical state selectivity on histidine and acetamide using synchrotron radiation

    International Nuclear Information System (INIS)

    We report on ultraviolet resonance Raman scattering experiments carried out on two model substances: histidine and acetamide using a UV synchrotron radiation source. In the case of aqueous histidine solution each protonated state of histidine tautomers was selectively excited by tuning the incident wavelength and the vibrational state of each protonated state was studied. We also demonstrated that the local pH condition of histidine can be identified directly from the spectra above pH 9. In the case of acetamide, the resonance Raman bands of acetamide with a stronger hydrogen bond at the NH2 site and weaker hydrogen bond at the C=O site were selectively observed. These findings will extend the selectivity and sensitivity of RR spectroscopy that is helpful to understanding protein functionality. (author)

  18. The approach to risk analysis in three industries: nuclear power, space systems, and chemical process

    International Nuclear Information System (INIS)

    The aerospace, nuclear power, and chemical processing industries are providing much of the incentive for the development and application of advanced risk analysis techniques to engineered systems. Risk analysis must answer three basic questions: What can go wrong? How likely is it? and What are the consequences? The result of such analyses is not only a quantitative answer to the question of 'What is the risk', but, more importantly, a framework for intelligent and visible risk management. Because of the societal importance of the subject industries and the amount of risk analysis activity involved in each, it is interesting to look for commonalities, differences, and, hopefully, a basis for some standardization. Each industry has its strengths: the solid experience base of the chemical industry, the extensive qualification and testing procedures of the space industry, and the integrative and quantitative risk and reliability methodologies developed for the nuclear power industry. In particular, most advances in data handling, systems interaction modeling, and uncertainty analysis have come from the probabilistic risk assessment work in the nuclear safety field. In the final analysis, all three industries would greatly benefit from a more deliberate technology exchange program in the rapidly evolving discipline of quantitative risk analysis. (author)

  19. THz-Raman: accessing molecular structure with Raman spectroscopy for enhanced chemical identification, analysis, and monitoring

    Science.gov (United States)

    Heyler, Randy A.; Carriere, James T. A.; Havermeyer, Frank

    2013-05-01

    Structural analysis via spectroscopic measurement of rotational and vibrational modes is of increasing interest for many applications, since these spectra can reveal unique and important structural and behavioral information about a wide range of materials. However these modes correspond to very low frequency (~5cm-1 - 200cm-1, or 150 GHz-6 THz) emissions, which have been traditionally difficult and/or expensive to access through conventional Raman and Terahertz spectroscopy techniques. We report on a new, inexpensive, and highly efficient approach to gathering ultra-low-frequency Stokes and anti-Stokes Raman spectra (referred to as "THz-Raman") on a broad range of materials, opening potential new applications and analytical tools for chemical and trace detection, identification, and forensics analysis. Results are presented on explosives, pharmaceuticals, and common elements that show strong THz-Raman spectra, leading to clear discrimination of polymorphs, and improved sensitivity and reliability for chemical identification.

  20. HRI catalytic two-stage liquefaction (CTSL) process materials: chemical analysis and biological testing

    Energy Technology Data Exchange (ETDEWEB)

    Wright, C.W.; Later, D.W.

    1985-12-01

    This report presents data from the chemical analysis and biological testing of coal liquefaction materials obtained from the Hydrocarbon Research, Incorporated (HRI) catalytic two-stage liquefaction (CTSL) process. Materials from both an experimental run and a 25-day demonstration run were analyzed. Chemical methods of analysis included adsorption column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, low-voltage probe-inlet mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The biological activity was evaluated using the standard microbial mutagenicity assay and an initiation/promotion assay for mouse-skin tumorigenicity. Where applicable, the results obtained from the analyses of the CTSL materials have been compared to those obtained from the integrated and nonintegrated two-stage coal liquefaction processes. 18 refs., 26 figs., 22 tabs.