Homogeneity and evaluation of the new NIST leaf certified reference materials

International Nuclear Information System (INIS)

Becker, D.A.

1990-01-01

The NIST has produced and is in the process of certifying two new leaf CRMs, SRM1515 Apple Leaves and SRM 1547 Peach Leaves, as replacements for the no longer available NBS Orchard Leaves and the almost depleted Citrus Leaves. These two new materials have been processed and are being thoroughly evaluated and should provide the most advanced natural matrix botanical trace-element reference materials available. Caution should be used in determining a basis weight (drying) for these CRMs because of their very fine particle size. Homogeneity has been established by instrumental neutron activation analysis on both leaf materials for five elements, to date, to better than 1.5% (1 s) for 100-mg sample sizes

Consensus values for NIST biological and environmental Standard Reference Materials

International Nuclear Information System (INIS)

Roelandts, I.; Gladney, E.S.

1998-01-01

The National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards or NBS) has produced numerous Standard Reference Materials (SRM) for use in biological and environmental analytical chemistry. The value listed on the ''NIST Certificate of Analysis'' is the present best estimate of the ''true'' concentration of that element and is not expected to deviate from that concentration by more than the stated uncertainty. However, NIST does not certify the elemental concentration of every constituent and the number of elements reported in the NIST programs tends to be limited.Numerous analysts have published concentration data on these reference materials. Major journals in analytical chemistry, books, proceedings and ''technical reports'' have been surveyed to collect these available literature values. A standard statistical approach has been employed to evaluate the compiled data. Our methodology has been developed in a series of previous papers. Some subjective criteria are first used to reject aberrant data. Following these eliminations, an initial arithmetic mean and standard deviation (S.D.) are computed from remaining data for each element. All data now outside two S.D. from the initial mean are dropped and a second mean and S.D. recalculated. These final means and associated S.D. are reported as ''consensus values'' in our tables. (orig.)

Neutron activation analysis with pre- and post-irradiation chemical separation for the value assignments of Al, V, and Ni in the new bovine liver SRM 1577C

International Nuclear Information System (INIS)

Zeisler, R.; Tomlin, B.E.; Murphy, K.E.

2009-01-01

Instrumental neutron activation analysis as carried out at the National Institute of Standards and Technology (NIST) is inadequate for determining Al, Ni, and V at the levels found in the newly prepared Standard Reference Material R (SRM) 1577c Bovine Liver. To overcome shortcomings in the value assignment, the authors initiated a cooperative approach using NAA with previously established chemical separation procedures and with significantly different neutron energy spectra to determine Al and V with pre-irradiation separation of the elements at NIST, and V and Ni with post-irradiation separation at the Nuclear Physics Institute Rez. The determinations were confirmed with the analyses of several SRMs. The work supported the certification of mass fraction values for V and Ni in SRM 1577c. (author)

Elemental analysis using instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry: a comparative study

International Nuclear Information System (INIS)

Chung, Yong Sam; Choi, Kwang Soon; Moon, Jong Hwa; Kim, Sun Ha; Lim, Jong Myoung; Kim, Young Jin; Quraishi, Shamshad Begum

2003-05-01

Elemental analyses for certified reference materials were carried out using instrumental neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. Five Certified Reference Materials (CRM) were selected for the study on comparative analysis of environmental samples. The CRM are Soil (NIST SRM 2709), Coal fly ash (NIST SRM 1633a), urban dust (NIST SRM 1649a) and air particulate on filter media (NIST SRM 2783 and human hair (GBW 09101)

Participation of SRM5/CDC28, SRM8/NET1 and SRM12/HF11 genes in activation of checkpoints of Yeast Saccharomyces Cerevisiae

International Nuclear Information System (INIS)

Kadyshevskaya, E.Yu.; Koltovaya, N.A.

2007-01-01

It is known that there are about twenty checkpoint genes in yeast Saccharomyces cerevisiae. We study participation of SRM genes selected as genes affecting genetic stability and radiosensitivity. It has been shown that srm5/cdc28-srm, srm8/net1-srm, srm12/hfil-srm mutations prevent checkpoint activation by DNA damage, particularly G0/S-checkpoint (srm5, srm8), G1/S-checkpoint (srm5, srm8, srm12), S-checkpoint (srm5, srm12) and G2-checkpoint (srm5). These data indicate, at least in budding yeast, CDC28/SRM5, HF11/ADA1/SRM12 and NET1/SRM8 genes mediate cellular response induced by DNA damage including checkpoint control

Examination of quantitative accuracy of PIXE analysis for atmospheric aerosol particle samples. PIXE analysis of NIST air particulate on filter media

International Nuclear Information System (INIS)

Saitoh, Katsumi; Sera, Koichiro

2005-01-01

In order to confirm accuracy of the direct analysis of filter samples containing atmospheric aerosol particles collected on a polycarbonate membrane filter by PIXE, we carried out PIXE analysis on a National Institute of Standards and Technology (NIST, USA) air particulate on filter media (SRM 2783). For 16 elements with NIST certified values determined by PIXE analysis - Na, Mg, Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb - quantitative values were 80-110% relative to NIST certified values except for Na, Al, Si and Ni. Quantitative values of Na, Al and Si were 140-170% relative to NIST certified values, which were all high, and Ni was 64%. One possible reason why the quantitative values of Na, Al and Si were higher than the NIST certified values could be the difference in the X-ray spectrum analysis method used. (author)

High accuracy determination of trace elements in NIST standard reference materials by isotope dilution ICP-MS

International Nuclear Information System (INIS)

Paulsen, P.J.; Beary, E.S.

1996-01-01

At NIST (National Institute of Standards and Technology), ICP-MS ID (inductively coupled mass spectrometry isotope dilution) has been used to certify a wide range of elements in a variety of materials with high accuracy. Both the chemical preparation and instrumental procedures are simpler than with other ID mass spectrometric techniques. The ICP-MS has picogram/ml detection limits for most elements using fixed operating parameters. Chemical separations are required only to remove an interference (from molecular ions as well as isobaric atoms), or to pre-concentrate the analyte. For example, chemical separations were required for the analysis of SRM 2711, Montana II Soil, but not for boron in peach leaves, SRM 1547.(3 refs., 3 tabs., 2 figs

Simultaneous determination of water-soluble vitamins in SRM 1849 Infant/Adult Nutritional Formula powder by liquid chromatography-isotope dilution mass spectrometry.

Science.gov (United States)

Goldschmidt, Robert J; Wolf, Wayne R

2010-05-01

Assessing dietary intake of vitamins from all sources, including foods, dietary supplements, and fortified foods, would be aided considerably by having analytical methodologies that are capable of simultaneous determination of several vitamins. Vitamins naturally present in foods may occur in different chemical forms, with levels ranging over several orders of magnitude. Vitamins in dietary supplements and fortified foods, however, are typically added in a single chemical form, and matrix issues are usually not as complex. These sources should thus be relatively amenable to approaches that aim for simultaneous determination of multiple vitamins. Our recent work has focused on development of liquid chromatography (LC)-UV/fluorescence and LC-tandem mass spectrometry methods for the simultaneous determination of water-soluble vitamins (thiamine, niacin, pyridoxine, pantothenic acid, folic acid, biotin, and riboflavin) in dietary supplement tablets and fortified foods, such as formula powders and breakfast cereals. As part of the validation of our methods and collaboration in characterization of a new NIST SRM 1849 Infant/Adult Nutritional Formula powder, we report data on SRM 1849 using isotope dilution mass spectrometric methods. Use of available NIST Standard Reference Materials(R) as test matrices in our method development and validation gives a benchmark for future application of these methods. We compare three chromatographic approaches and provide data on stability of vitamin standard solutions for LC-based multiple vitamin determinations.

Test Capability of Comparative NAA Method in Analysis of Long Lived Element in SRM 1648

International Nuclear Information System (INIS)

Sri-Wardani

2005-01-01

The comparative NAA method had been examine on the analysis of long-lived elements content in air particulate sample of NIST.SRM 1648 for evaluation of a capability of comparative NAA method that used at P2TRR. From the result of analysis it could be determined analysis elements contained in the sample, namely: Sc, Co, Zn, Br, Rb, Sb, Hf and Th with optimum results in bias of 10%. The optimum result of long-lived elements obtained on a good accuracy and precision. From the analysis data obtained showed that the comparative NAA method with Gamma Trac and APTEC software capable to analyze several kinds of elements in environmental samples. Therefore, this method could be implement in biological and healthy samples. (author)

Determination of trace elements in standard reference materials by the ko-standardization method

International Nuclear Information System (INIS)

Smodis, B.; Jacimovic, R.; Stegnar, P.; Jovanovic, S.

1990-01-01

The k o -standardization method is suitable for routine multielement determinations by reactor neutron activation analysis (NAA). Investigation of NIST standard reference materials SRM 1571 Orchard Leaves, SRM 1572 Citrus leaves, and SRM 1573 Tomato Leaves showed the systematic error of 12 certified elements determined to be less than 8%. Thirty-four elements were determined in NIST proposed SRM 1515 Apple Leaves

Use of composite materials for the determination of Cu, As, Mo, Cd and Sb in biological materials by radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Lucanikova, M.; John, J.; Kucera, J.; Sebesta, F.

2006-01-01

New composite materials were developed and tested for determination of Cu, As, Mo, Cd, and Sb in biological materials by radiochemical neutron activation analysis (RNAA). The materials were prepared by incorporation of solid zinc diethyldithiocarbamate or liquid bis(2,4,4-trimethylpentyl)dithiophosphinic acid (CYANEX 301) into a polyacrylonitrile (PAN) binding matrix. The accuracy of the RNAA procedures was proved by analysis of NIST SRM-1515 Apple Leaves, NIST SRM-1577b Bovine Liver, and NIST SRM-1549 Non Fat Milk Powder. (author)

Biomass-burning derived aromatic acids in NIST standard reference material 1649b and the environmental implications

Science.gov (United States)

Gao, Shaopeng; Xu, Baiqing; Dong, Xueling; Zheng, Xiaoyan; Wan, Xin; Kang, Shichang; Song, Qiuyin; Kawamura, Kimitaka; Cong, Zhiyuan

2018-07-01

Biomass burning is a serious problem in the environment and climate system. However, the source identification of biomass-burning aerosols was somewhat impeded, partly due to the difficulty in quantification of relevant molecular markers. In this study, we present reference values for five aromatic acids (including p-hydroxybenzoic, vanillic, dehydroabietic, syringic and p-coumaric acids) in the NIST Standard Reference Material (SRM) 1649b. The concentration of levoglucosan was also revisited. Notable positive matrix effect was found for vanillic, dehydroabietic, syringic and coumaric acid. Using the standard addition method, the average value of p-hydroxybenzoic, vanillic, syringic, dehydroabietic and p-coumaric acids in SRM 1649b were found to be 26.9, 9.53, 1.13, 7.60 and 1.66 μg g-1, respectively. The analytical method developed in this study was also applied to the PM10 samples from Beijing and PM2.5 samples from South Asia (Godavari, Nepal). The ratios of vanillic to p-hydroxybenzoic acid and syringic to vanillic acid further suggested that their biomass-burning types are mainly related to hard wood and herbaceous species (i.e., agricultural residues).

Retrospective Analysis of NIST Standard Reference Material 1450, Fibrous Glass Board, for Thermal Insulation Measurements

Science.gov (United States)

Zarr, Robert R; Heckert, N Alan; Leigh, Stefan D

2014-01-01

Thermal conductivity data acquired previously for the establishment of Standard Reference Material (SRM) 1450, Fibrous Glass Board, as well as subsequent renewals 1450a, 1450b, 1450c, and 1450d, are re-analyzed collectively and as individual data sets. Additional data sets for proto-1450 material lots are also included in the analysis. The data cover 36 years of activity by the National Institute of Standards and Technology (NIST) in developing and providing thermal insulation SRMs, specifically high-density molded fibrous-glass board, to the public. Collectively, the data sets cover two nominal thicknesses of 13 mm and 25 mm, bulk densities from 60 kg·m−3 to 180 kg·m−3, and mean temperatures from 100 K to 340 K. The analysis repetitively fits six models to the individual data sets. The most general form of the nested set of multilinear models used is given in the following equation: λ(ρ,T)=a0+a1ρ+a2T+a3T3+a4e−(T−a5a6)2where λ(ρ,T) is the predicted thermal conductivity (W·m−1·K−1), ρ is the bulk density (kg·m−3), T is the mean temperature (K) and ai (for i = 1, 2, … 6) are the regression coefficients. The least squares fit results for each model across all data sets are analyzed using both graphical and analytic techniques. The prevailing generic model for the majority of data sets is the bilinear model in ρ and T. λ(ρ,T)=a0+a1ρ+a2T One data set supports the inclusion of a cubic temperature term and two data sets with low-temperature data support the inclusion of an exponential term in T to improve the model predictions. Physical interpretations of the model function terms are described. Recommendations for future renewals of SRM 1450 are provided. An Addendum provides historical background on the origin of this SRM and the influence of the SRM on external measurement programs. PMID:26601034

Functional description of PreSRM v1.3. Technical manual for use of PreSRM (Preprocessor Standard Calculation Methods); Functionele omschrijving PreSRM v1.3. Technische handleiding voor gebruik van PreSRM (Preprocessor Standaard RekenMethoden)

Energy Technology Data Exchange (ETDEWEB)

Vermeulen, A.T. [ECN Environment and Energy Engineering, Petten (Netherlands)

2013-07-15

The PreSRM software library is prescribed in The Netherlands by the government to be used in the dispersion modeling of air pollution when evaluating air quality guidelines in outside air. The code is maintained by ECN and needs to be updated annually. This technical manual describes the use of PreSRM by programmers and documents the update for the current year 2013, including all updated meteorological and air quality background information for the year 2012 [Dutch] PreSRM is een software bibliotheek voor rekenmodellen gebruikt bij de beoordeling van luchtkwaliteit. In Nederland schrijft de Regeling Beoordeling Luchtkwaliteit (RBL) voor onder welke condities welke rekenmethodes gebruikt moeten worden om aan de luchtkwaliteitsnormen te toetsen. In de RBL worden drie Standaard RekenMethodes (SRM's) beschreven. Tevens wordt daarin vastgesteld welke invoergegevens gebruikt moeten worden voor emissies, achtergrondconcentraties, meteorologie en terreinruwheid. Deze gegevens worden jaarlijks geactualiseerd. Dit rapport is een technische handleiding voor de programmeurs en ontwikkelaars van de implementaties van standaard rekenmethoden en systeembeheerders van gebruikers en beschrijft aanpassingen in de huidige versie van de bibliotheek.

Horizontally scaling dCache SRM with the Terracotta platform

International Nuclear Information System (INIS)

Perelmutov, T; Crawford, M; Moibenko, A; Oleynik, G

2011-01-01

The dCache disk caching file system has been chosen by a majority of LHC experiments' Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a single node. Using the Terracotta platform[l], we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.

Horizontally scaling dChache SRM with the Terracotta platform

International Nuclear Information System (INIS)

Perelmutov, T.; Crawford, M.; Moibenko, A.; Oleynik, G.

2011-01-01

The dCache disk caching file system has been chosen by a majority of LHC experiments Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a single node. Using the Terracotta platform, we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.

Polycyclic aromatic hydrocarbons (PAHs) in a coal tar standard reference material - SRM 1597a updated

Energy Technology Data Exchange (ETDEWEB)

Wise, Stephen A.; Poster, Dianne L.; Rimmer, Catherine A.; Schubert, Patricia; Sander, Lane C.; Schantz, Michele M. [National Institute of Standards and Technology (NIST), Analytical Chemistry Division, Gaithersburg, MD (United States); Leigh, Stefan D. [National Institute of Standards and Technology (NIST), Statistical Engineering Division, Gaithersburg, MD (United States); Moessner, Stephanie [National Institute of Standards and Technology (NIST), Analytical Chemistry Division, Gaithersburg, MD (United States); GMP/Comparator Labs, Werthenstein Chemie AG, Industrie Nord, Schachen (Switzerland)

2010-09-15

SRM 1597 Complex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar, originally issued in 1987, was recently reanalyzed and reissued as SRM 1597a with 34 certified, 46 reference, and 12 information concentrations (as mass fractions) for polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) including methyl-substituted PAHs and PASHs. The certified and reference concentrations (as mass fractions) were based on results of analyses of the coal tar material using multiple analytical techniques including gas chromatography/mass spectrometry on four different stationary phases and reversed-phase liquid chromatography. SRM 1597a is currently the most extensively characterized SRM for PAHs and PASHs. (orig.)

The 2016 NIST Speaker Recognition Evaluation

Science.gov (United States)

2017-08-20

impact on system performance. Index Terms: NIST evaluation, NIST SRE, speaker detection, speaker recognition, speaker verification 1. Introduction NIST... self -reported. Second, there were two training conditions in SRE16, namely fixed and open. In the fixed training condition, par- ticipants were only

NIST display colorimeter calibration facility

Science.gov (United States)

Brown, Steven W.; Ohno, Yoshihiro

2003-07-01

A facility has been developed at the National Institute of Standards and Technology (NIST) to provide calibration services for color-measuring instruments to address the need for improving and certifying the measurement uncertainties of this type of instrument. While NIST has active programs in photometry, flat panel display metrology, and color and appearance measurements, these are the first services offered by NIST tailored to color-measuring instruments for displays. An overview of the facility, the calibration approach, and associated uncertainties are presented. Details of a new tunable colorimetric source and the development of new transfer standard instruments are discussed.

Application of snowmelt runoff model (SRM in mountainous watersheds: A review

Directory of Open Access Journals (Sweden)

Shalamu Abudu

2012-06-01

Full Text Available The snowmelt runoff model (SRM has been widely used in simulation and forecast of streamflow in snow-dominated mountainous basins around the world. This paper presents an overall review of worldwide applications of SRM in mountainous watersheds, particularly in data-sparse watersheds of northwestern China. Issues related to proper selection of input climate variables and parameters, and determination of the snow cover area (SCA using remote sensing data in snowmelt runoff modeling are discussed through extensive review of literature. Preliminary applications of SRM in northwestern China have shown that the model accuracies are relatively acceptable although most of the watersheds lack measured hydro-meteorological data. Future research could explore the feasibility of modeling snowmelt runoff in data-sparse mountainous watersheds in northwestern China by utilizing snow and glacier cover remote sensing data, geographic information system (GIS tools, field measurements, and innovative ways of model parameterization.

On the effect of grain burnback on STS-SRM fragment velocity

International Nuclear Information System (INIS)

Eck, M.B.; Mukunda, M.

1991-01-01

Concerns raised during the Ulysses Final Safety Analysis Review (FSAR) process called the solid rocket motor (SRM) fragment velocity prediction model into question. The specific area of concern was that there was a section of the SRM casing which was exposed to SRM chamber pressure as the grain (fuel) was consumed. These questions centered on the velocity of fragments which originated from the field joint region given that failure occurred between 37 and 72 seconds mission elapsed time (MET). Two dimensional coupled Eulerian-Lagrangian calculations were performed to assess the hot gas flow field which resulted from SRM casing fragmentation. The fragment to gas interface-pressure time-history obtained from these analyses was reduced to a boundary condition algorithm which was applied to an explicit-time-integration, finite element, three dimensional shell model of the SRM casing and unburned fuel. The results of these calculations showed that the velocity of fragments originating in the field joint was adequately described by the range of velocities given in the Shuttle Data Book (1988). Based on these results, no further analyses were required, and approval was obtained from the Launch Abort Subpanel of the Interagency Nuclear Safety Review Panel to use the SRM fragment velocity environments presented in the Ulysses FSAR (1990)

NIST Gonio-spectroradiometer

Data.gov (United States)

Federal Laboratory Consortium — The NIST gonio-spectroradiometer is used to measure total spectral radiant flux (TSRF) of incandescent lamps. The instrument consists of a 3-axis scanning mechanism;...

Reference metrology in a research fab: the NIST clean calibrations thrust

Science.gov (United States)

Dixson, Ronald; Fu, Joe; Orji, Ndubuisi; Renegar, Thomas; Zheng, Alan; Vorburger, Theodore; Hilton, Al; Cangemi, Marc; Chen, Lei; Hernandez, Mike; Hajdaj, Russell; Bishop, Michael; Cordes, Aaron

2009-03-01

In 2004, the National Institute of Standards and Technology (NIST) commissioned the Advanced Measurement Laboratory (AML) - a state-of-the-art, five-wing laboratory complex for leading edge NIST research. The NIST NanoFab - a 1765 m2 (19,000 ft2) clean room with 743 m2 (8000 ft2) of class 100 space - is the anchor of this facility and an integral component of the new Center for Nanoscale Science and Technology (CNST) at NIST. Although the CNST/NanoFab is a nanotechnology research facility with a different strategic focus than a current high volume semiconductor fab, metrology tools still play an important role in the nanofabrication research conducted here. Some of the metrology tools available to users of the NanoFab include stylus profiling, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Since 2001, NIST has collaborated with SEMATECH to implement a reference measurement system (RMS) using critical dimension atomic force microscopy (CD-AFM). NIST brought metrology expertise to the table and SEMATECH provided access to leading edge metrology tools in their clean room facility in Austin. Now, in the newly launched "clean calibrations" thrust at NIST, we are implementing the reference metrology paradigm on several tools in the CNST/NanoFab. Initially, we have focused on calibration, monitoring, and uncertainty analysis for a three-tool set consisting of a stylus profiler, an SEM, and an AFM. Our larger goal is the development of new and supplemental calibrations and standards that will benefit from the Class 100 environment available in the NanoFab and offering our customers calibration options that do not require exposing their samples to less clean environments. Toward this end, we have completed a preliminary evaluation of the performance of these instruments. The results of these evaluations suggest that the achievable uncertainties are generally consistent with our measurement goals.

Validation of method in instrumental NAA for food products sample

International Nuclear Information System (INIS)

Alfian; Siti Suprapti; Setyo Purwanto

2010-01-01

NAA is a method of testing that has not been standardized. To affirm and confirm that this method is valid. it must be done validation of the method with various sample standard reference materials. In this work. the validation is carried for food product samples using NIST SRM 1567a (wheat flour) and NIST SRM 1568a (rice flour). The results show that the validation method for testing nine elements (Al, K, Mg, Mn, Na, Ca, Fe, Se and Zn) in SRM 1567a and eight elements (Al, K, Mg, Mn, Na, Ca, Se and Zn ) in SRM 1568a pass the test of accuracy and precision. It can be conclude that this method has power to give valid result in determination element of the food products samples. (author)

Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Deepak [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2013-01-01

RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

The new NIST atomic spectra database

International Nuclear Information System (INIS)

Kelleher, D.E.; Martin, W.C.; Wiese, W.L.; Sugar, J.; Fuhr, J.R.; Olsen, K.; Musgrove, A.; Mohr, P.J.; Reader, J.; Dalton, G.R.

1999-01-01

The new atomic spectra database (ASD), Version 2.0, of the National Institute of Standards and Technology (NIST) contains significantly more data and covers a wider range of atomic and ionic transitions and energy levels than earlier versions. All data are integrated. It also has a new user interface and search engine. ASD contains spectral reference data which have been critically evaluated and compiled by NIST. Version 2.0 contains data on 900 spectra, with about 70000 energy levels and 91000 lines ranging from about 1 Aangstroem to 200 micrometers, roughly half of which have transition probabilities with estimated uncertainties. References to the NIST compilations and original data sources are listed in the ASD bibliography. A detailed ''Help'' file serves as a user's manual, and full search and filter capabilities are provided. (orig.)

Analysis of elements present in beers and brewing waters by neutron activation analysis

International Nuclear Information System (INIS)

Krausova, Ivana; Kucera, Jan; Dostalek, Pavel; Potesil, Vaclav

2011-01-01

Neutron activation analysis (NAA) was used for determination of Si, Na, K, Ca, Sc, V, Cr, Mn, Fe, Co, Zn, Rb, Cs, and La in Czech beers and brewing waters. The Si concentration in beer determined by the reaction 29 Si(n,p) 29 Al with fast neutrons confirmed that beer is an important Si source in human diet. Determination of other trace elements by NAA with the whole spectrum of reactor neutrons aimed at the feasibility of identification of Gambrinus beers brewed in various breweries. The elements Ca and V appeared to be the best candidates for this purpose. The concentrations of elements determined by NAA were also compared with the recommended daily element intake for humans. The accuracy of the method was proved by analysis of reference materials, specifically NIST SRM 2704 Buffalo River Sediment, NIST SRM 1633b Coal Fly Ash, and NIST SRM 1515 Apple Leaves. (author)

Analysis of Bone Meal (NIST 1486) and Bone Ash (NIST 1400) reference materials by neutron activation method; Analise de materiais de referencia Bone Meal (NIST 1486) e Bone Ash (NIST 1400) pelo metodo de ativacao com neutrons

Energy Technology Data Exchange (ETDEWEB)

Takata, Marcelo K.; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Borelli, Aurelio [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina

1999-11-01

In this work instrumental neutron activation analysis has been applied to determine Ba, ca, Cl, Cr, fe, Mg, Mn, Na, P, Sb, Sc, Sr and Zn in two biological reference materials NIST 1486 Bone Meal and NIST 1400 Bone Ash. The purpose of this work was to evaluate the precision and the accuracy of the results as well as to give a contribution to certificate these materials. Interferences found in the determination of some elements were also discussed. (author) 8 refs., 4 tabs.

Rhythmic Behavior Is Controlled by the SRm160 Splicing Factor in Drosophila melanogaster.

Science.gov (United States)

Beckwith, Esteban J; Hernando, Carlos E; Polcowñuk, Sofía; Bertolin, Agustina P; Mancini, Estefania; Ceriani, M Fernanda; Yanovsky, Marcelo J

2017-10-01

Circadian clocks organize the metabolism, physiology, and behavior of organisms throughout the day-night cycle by controlling daily rhythms in gene expression at the transcriptional and post-transcriptional levels. While many transcription factors underlying circadian oscillations are known, the splicing factors that modulate these rhythms remain largely unexplored. A genome-wide assessment of the alterations of gene expression in a null mutant of the alternative splicing regulator SR-related matrix protein of 160 kDa (SRm160) revealed the extent to which alternative splicing impacts on behavior-related genes. We show that SRm160 affects gene expression in pacemaker neurons of the Drosophila brain to ensure proper oscillations of the molecular clock. A reduced level of SRm160 in adult pacemaker neurons impairs circadian rhythms in locomotor behavior, and this phenotype is caused, at least in part, by a marked reduction in period ( per ) levels. Moreover, rhythmic accumulation of the neuropeptide PIGMENT DISPERSING FACTOR in the dorsal projections of these neurons is abolished after SRm160 depletion. The lack of rhythmicity in SRm160-downregulated flies is reversed by a fully spliced per construct, but not by an extra copy of the endogenous locus, showing that SRm160 positively regulates per levels in a splicing-dependent manner. Our findings highlight the significant effect of alternative splicing on the nervous system and particularly on brain function in an in vivo model. Copyright © 2017 by the Genetics Society of America.

An Efficient and Simplified Model for Forecasting using SRM

Directory of Open Access Journals (Sweden)

Hafiz Muhammad Shahzad Asif

2014-01-01

Full Text Available Learning form continuous financial systems play a vital role in enterprise operations. One of the most sophisticated non-parametric supervised learning classifiers, SVM (Support Vector Machines, provides robust and accurate results, however it may require intense computation and other resources. The heart of SLT (Statistical Learning Theory, SRM (Structural Risk Minimization Principle can also be used for model selection. In this paper, we focus on comparing the performance of model estimation using SRM with SVR (Support Vector Regression for forecasting the retail sales of consumer products. The potential benefits of an accurate sales forecasting technique in businesses are immense. Retail sales forecasting is an integral part of strategic business planning in areas such as sales planning, marketing research, pricing, production planning and scheduling. Performance comparison of support vector regression with model selection using SRM shows comparable results to SVR but in a computationally efficient manner. This research targeted the real life data to conclude the results after investigating the computer generated datasets for different types of model building

An efficient and simplified model for forecasting using SRM

International Nuclear Information System (INIS)

Asif, H.M.; Hyat, M.F.; Ahmad, T.

2014-01-01

Learning form continuous financial systems play a vital role in enterprise operations. One of the most sophisticated non-parametric supervised learning classifiers, SVM (Support Vector Machines), provides robust and accurate results, however it may require intense computation and other resources. The heart of SLT (Statistical Learning Theory), SRM (Structural Risk Minimization )Principle can also be used for model selection. In this paper, we focus on comparing the performance of model estimation using SRM with SVR (Support Vector Regression) for forecasting the retail sales of consumer products. The potential benefits of an accurate sales forecasting technique in businesses are immense. Retail sales forecasting is an integral part of strategic business planning in areas such as sales planning, marketing research, pricing, production planning and scheduling. Performance comparison of support vector regression with model selection using SRM shows comparable results to SVR but in a computationally efficient manner. This research targeted the real life data to conclude the results after investigating the computer generated datasets for different types of model building. (author)

Measurement quality assurance for beta particle calibrations at NIST

Energy Technology Data Exchange (ETDEWEB)

Soares, C.G.; Pruitt, J.S. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

1993-12-31

Standardized beta-particle fields have been established in an international standard and have been adopted for use in several U.S. dosimeter and instrument testing standards. Calibration methods and measurement quality assurance procedures employed at the National Institute of Standards and Technology (NIST) for beta-particle calibrations in these reference fields are discussed. The calibration facility including the NIST-automated extrapolation ionization chamber is described, and some sample results of calibrations are shown. Methods for establishing and maintaining traceability to NIST of secondary laboratories are discussed. Currently, there are problems in finding a good method for routine testing of traceability to NIST. Some examples of past testing methods are given and solutions to this problem are proposed.

Measurement quality assurance for beta particle calibrations at NIST

International Nuclear Information System (INIS)

Soares, C.G.; Pruitt, J.S.

1993-01-01

Standardized beta-particle fields have been established in an international standard and have been adopted for use in several U.S. dosimeter and instrument testing standards. Calibration methods and measurement quality assurance procedures employed at the National Institute of Standards and Technology (NIST) for beta-particle calibrations in these reference fields are discussed. The calibration facility including the NIST-automated extrapolation ionization chamber is described, and some sample results of calibrations are shown. Methods for establishing and maintaining traceability to NIST of secondary laboratories are discussed. Currently, there are problems in finding a good method for routine testing of traceability to NIST. Some examples of past testing methods are given and solutions to this problem are proposed

Optimization of technology SRM (Supply Relationship Management) in oil companies supply; Otimizacao de tecnologia SRM (Supply Relationship Management) em empresas da cadeia do petroleo

Energy Technology Data Exchange (ETDEWEB)

Jovine, Renata Machado; Bastos, Luciana de Barros [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

2004-07-01

Recently, becomes very important improve the Supplier Relationship in order to the enterprises reduce costs and increase their efficiency. By that fact, in the last years, people started talking about Supplier Relationship Management - SRM and technologies are being developed to support this management. At Petroleum's Industry, every source should be at the right place, at the right time and should have quality otherwise the damages can be disastrous, considering the high cost of the equipment and environmental questions. So, this project intent to study the SRM of one enterprise of the petroleum area in order to analyze this technology, study references and analyzing the practices related to SRM, criticize and propose improvements that could be done. In this study, was concluded that technology is being developed but there is still place for improvement in the practice. (author)

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Energy Technology Data Exchange (ETDEWEB)

Huang, Shih-Yi [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min{sup −1} methane (CH{sub 4}) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g{sup −1} for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g{sup −1} (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

International Nuclear Information System (INIS)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A.C.

2014-01-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min −1 methane (CH 4 ) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g −1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g −1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour

Value assignment of nutrient concentrations in five standard reference materials and six reference materials.

Science.gov (United States)

Sharpless, K E; Gill, L M

2000-01-01

A number of food-matrix reference materials (RMs) are available from the National Institute of Standards and Technology (NIST) and from Agriculture Canada through NIST. Most of these materials were originally value-assigned for their elemental composition (major, minor, and trace elements), but no additional nutritional information was provided. Two of the materials were certified for selected organic constituents. Ten of these materials (Standard Reference Material [SRM] 1,563 Cholesterol and Fat-Soluble Vitamins in Coconut Oil [Natural and Fortified], SRM 1,566b Oyster Tissue, SRM 1,570a Spinach Leaves, SRM 1,974a Organics in Mussel Tissue (Mytilus edulis), RM 8,415 Whole Egg Powder, RM 8,418 Wheat Gluten, RM 8,432 Corn Starch, RM 8,433 Corn Bran, RM 8,435 Whole Milk Powder, and RM 8,436 Durum Wheat Flour) were recently distributed by NIST to 4 laboratories with expertise in food analysis for the measurement of proximates (solids, fat, protein, etc.), calories, and total dietary fiber, as appropriate. SRM 1846 Infant Formula was distributed as a quality control sample for the proximates and for analysis for individual fatty acids. Two of the materials (Whole Egg Powder and Whole Milk Powder) were distributed in an earlier interlaboratory comparison exercise in which they were analyzed for several vitamins. Value assignment of analyte concentrations in these 11 SRMs and RMs, based on analyses by the collaborating laboratories, is described in this paper. These materials are intended primarily for validation of analytical methods for the measurement of nutrients in foods of similar composition (based on AOAC INTERNATIONAL's fat-protein-carbohydrate triangle). They may also be used as "primary control materials" in the value assignment of in-house control materials of similar composition. The addition of proximate information for 10 existing reference materials means that RMs are now available from NIST with assigned values for proximates in 6 of the 9 sectors of

A Position Sensorless Control Method for SRM Based on Variation of Phase Inductance

Science.gov (United States)

Komatsuzaki, Akitomo; Miki, Ichiro

Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position with a position sensor attached to the motor shaft. The use of the sensor increases the cost of the drive system and machine size, and furthermore the reliability of the system is reduced. Therefore, several approaches to eliminate the position sensor have already been reported. In this paper, a position sensorless control method based on the variation of the phase inductance is described. The phase inductance regularly varies with the rotor position. The SRM is controlled without the position sensor using the de-fluxing period and the phase inductance. The turn-off timing is determined by computing the difference of angle between the sampling point and the aligned point and the variation of angle during the de-fluxing period. In the magnetic saturation region, the phase inductance at the current when the effect of the saturation starts is computed and the sensorless control can be carried out using this inductance. Experimental results show that the SRM is well controlled without the position sensor using the proposed method.

77 FR 18791 - Proposed Information Collection; Comment Request; NIST Associates Information System

Science.gov (United States)

2012-03-28

... DEPARTMENT OF COMMERCE National Institute of Standards and Technology Proposed Information Collection; Comment Request; NIST Associates Information System AGENCY: National Institute of Standards and... access to the NIST campuses or NIST resources. The NIST Associates Information System (NAIS) information...

NIST high-dose calibration services

International Nuclear Information System (INIS)

Humphreys, J.C.

1989-01-01

There is a need for the standardization of high-dose measurements used in the radiation-processing industry in order to provide assured traceability to national standards. NIST provides dosimetry calibration services to this industry. One of these services involves administration of known absorbed doses of gamma rays to customer-supplied dosimeters. The dosimeters are packaged to provide electron equilibrium conditions and are irradiated in a standard 60 Co calibration facility; this provides a calibration of that batch of dosimeters. Another service consists of supplying to a customer calibrated transfer dosimeters for irradiation with the customer's radiation source. The irradiated transfer dosimeters are then returned to NIST for analysis; the results are reported to the customer, providing a calibration of the dose rate of the customer's source. (orig.)

NIST biometric evaluations and developments

Science.gov (United States)

Garris, Michael D.; Wilson, Charles L.

2005-05-01

This paper presents an R&D framework used by the National Institute of Standards and Technology (NIST) for biometric technology testing and evaluation. The focus of this paper is on fingerprint-based verification and identification. Since 9-11 the NIST Image Group has been mandated by Congress to run a program for biometric technology assessment and biometric systems certification. Four essential areas of activity are discussed: 1) developing test datasets, 2) conducting performance assessment; 3) technology development; and 4) standards participation. A description of activities and accomplishments are provided for each of these areas. In the process, methods of performance testing are described and results from specific biometric technology evaluations are presented. This framework is anticipated to have broad applicability to other technology and application domains.

NIST commitment to national MQA programs

Energy Technology Data Exchange (ETDEWEB)

Caswell, R.S. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

1993-12-31

The program of the Ionizing Radiation Division, Physics Laboratory is discussed, especially relating to standards, calibrations, and measurement quality assurance (MQA). The NIST program is {open_quotes}vertically integrated,{close_quotes} meaning that activities extend from fundamental research to measurement research to supplying services and data. Typical methods NIST uses to assure the quality of the national standards are presented. Some of the programs in x-ray, gamma-ray, electron, neutron, and radioactivity research which support MQA are presented. Examples are given of MQA activities.

NIST commitment to national MQA programs

International Nuclear Information System (INIS)

Caswell, R.S.

1993-01-01

The program of the Ionizing Radiation Division, Physics Laboratory is discussed, especially relating to standards, calibrations, and measurement quality assurance (MQA). The NIST program is open-quotes vertically integrated,close quotes meaning that activities extend from fundamental research to measurement research to supplying services and data. Typical methods NIST uses to assure the quality of the national standards are presented. Some of the programs in x-ray, gamma-ray, electron, neutron, and radioactivity research which support MQA are presented. Examples are given of MQA activities

Quality in the chemical analysis of biological matrices by fluorescence X-ray by energy dispersive; Qualidade nas analises quimicas de matrizes biologicas pela fluorescencia de raios-X por dispersao de energia

Energy Technology Data Exchange (ETDEWEB)

Sousa, Evely E. de; Paiva, Jose Daniel S. de; Franca, Elvis J. de; Almeida, Macio E.S.; Cantinha, Rebeca S.; Hazin, Clovis A., E-mail: evelysousa_182@hotmail.com, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2013-07-01

The aim of this study was to obtain multielement analytical curves of high analytical rigor to the analysis of biological matrices by the technique of fluorescence x-ray energy dispersive - EDXRF. Calibration curves were constructed from the reference materials IAEA 140, IAEA 155, IAEA V8, V10 to the International Atomic Energy Agency - IAEA, and SRM1515, SRM 1547, SRM 1570a, SRM 1573a, SEM 1567a, to the National Institute of Standards and Technology - NIST. After energy calibration, all samples were subjected to vacuum to the analyzes by 100 seconds for each group of chemical elements. The voltages used were respectively 15 keV for chemical elements with less than atomic number 22 and 50 keV for the others. After the construction of the curves, the analytical quality was assessed by the analysis of a portion-test of the reference material SRM 2976, also produced by NIST. Based on the number of certified reference materials used for construction of calibration curves in this work, quality analytical protocol was originated with considerable reliability for quantification of chemical elements in biological samples by EDXR.

Quality in the chemical analysis of biological matrices by fluorescence X-ray by energy dispersive

International Nuclear Information System (INIS)

Sousa, Evely E. de; Paiva, Jose Daniel S. de; Franca, Elvis J. de; Almeida, Macio E.S.; Cantinha, Rebeca S.; Hazin, Clovis A.

2013-01-01

The aim of this study was to obtain multielement analytical curves of high analytical rigor to the analysis of biological matrices by the technique of fluorescence x-ray energy dispersive - EDXRF. Calibration curves were constructed from the reference materials IAEA 140, IAEA 155, IAEA V8, V10 to the International Atomic Energy Agency - IAEA, and SRM1515, SRM 1547, SRM 1570a, SRM 1573a, SEM 1567a, to the National Institute of Standards and Technology - NIST. After energy calibration, all samples were subjected to vacuum to the analyzes by 100 seconds for each group of chemical elements. The voltages used were respectively 15 keV for chemical elements with less than atomic number 22 and 50 keV for the others. After the construction of the curves, the analytical quality was assessed by the analysis of a portion-test of the reference material SRM 2976, also produced by NIST. Based on the number of certified reference materials used for construction of calibration curves in this work, quality analytical protocol was originated with considerable reliability for quantification of chemical elements in biological samples by EDXR

Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique

International Nuclear Information System (INIS)

Parsapour, Amir; Dehkordi, Behzad Mirzaeian; Moallem, Mehdi

2015-01-01

In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated

Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique

Energy Technology Data Exchange (ETDEWEB)

Parsapour, Amir, E-mail: amirparsapour@gmail.com [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Dehkordi, Behzad Mirzaeian, E-mail: mirzaeian@eng.ui.ac.ir [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Moallem, Mehdi, E-mail: moallem@cc.iut.ac.ir [Department of Electrical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

2015-03-15

In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated.

How well could existing sensors detect the deployment of a solar radiation management (SRM) geoengineering effort?

Energy Technology Data Exchange (ETDEWEB)

Hurd, Alan J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-04-29

While the stated reason for asking this question is “to understand better our ability to warn policy makers in the unlikely event of an unanticipated SRM geoengineering deployment or large-scale field experiment”, my colleagues and I felt that motives would be important context because the scale of any meaningful SRM deployment would be so large that covert deployment seems impossible. However, several motives emerged that suggest a less-than-global effort might be important.

Topography measurements for determining the decay factors in surface replication

International Nuclear Information System (INIS)

Song, J; Zheng, A; Vorburger, T V; Rubert, P

2008-01-01

The electro-forming technique is used at National Institute of Standards and Technology (NIST) for the production of standard reference material (SRM) 2461 standard casings to support nationwide ballistics measurement traceability and measurement quality control in the US. In order to ensure that the SRM casings are produced with virtually the same surface topography, it is necessary to test the decay factors of the replication process. Twenty-six replica casings are replicated from the same master casing for the decay factor tests. The NIST topography measurement system is used for measurements and correlations of surface topography. The topography decays are quantified by the cross-correlation function maximum CCF max . Based on the test, it is expected that 256 SRM casings can be replicated from the same master with CCF max values higher than 95%

Application of the k{sub 0}-INAA method for analysis of biological samples at the pneumatic station of the IEA-R1 nuclear research reactor

Energy Technology Data Exchange (ETDEWEB)

Puerta, Daniel C.; Figueiredo, Ana Maria G.; Semmler, Renato, E-mail: dcpuerta@hotmail.com, E-mail: anamaria@ipen.br, E-mail: rsemmler@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Jacimovic, Radojko, E-mail: radojko.jacimovic@ijs.si [Jozef Stefan Institute (JSI), Ljubljana, LJU (Slovenia). Department of Environmental Sciences

2013-07-01

As part of the process of implementation of the k{sub 0}-INAA standardization method at the Neutron Activation Laboratory (LAN-IPEN), Sao Paulo, Brazil, this study presents the results obtained for the analysis of short and medium-lived nuclides in biological samples by k{sub 0}-INAA using the program k{sub 0}-IAEA, provided by the International Atomic Energy Agency (IAEA). The elements Al, Ba, Br, Na, K, Mn, Mg, Sr and V were determined with respect to gold ({sup 197}Au) using the pneumatic station facility of the IEA-R1 4.5 MW swimming pool nuclear research reactor, Sao Paulo. Characterization of the pneumatic station was carried out by using the 'bare triple-monitor' method with {sup 197}Au-{sup 96}Zr-{sup 94}Zr. The Certified Reference Material IRMM-530R Al-0.1%Au alloy and high purity zirconium comparators were used. The efficiency curves of the gamma-ray spectrometer used were determined by measuring calibrated radioactive sources at the usually utilized counting geometries. The method was validated by analyzing the reference materials NIST SRM 1547 Peach Leaves, INCT-MPH-2 Mixed Polish Herbs and NIST SRM 1573a Tomato Leaves. The concentration results obtained agreed with certified, reference and recommended values, showing relative errors (bias, %) less than 30% for most elements. The Coefficients of Variation were below 20%, showing a good reproducibility of the results. The E{sub n}-number showed that all results, except Na in NIST SRM 1547 and NIST SRM 1573a and Al in INCT-MPH-2, were within 95% confidence interval. (author)

Thermal conductivity and electrical resistivity standard reference materials: tungsten SRM's 730 and 799, from 4 to 30000K. Final report

International Nuclear Information System (INIS)

Hust, J.G.; Giarratano, P.J.

1975-09-01

A historical review of the development of thermophysical Standard Reference Materials, SRM's, is given and selection criteria of SRM's are listed. Thermal conductivity and electrical resistivity data for arc cast and sintered tungsten are compiled, analyzed, and correlated. Recommended values of thermal conductivity (SRM 730) and electrical resistivity (SRM 799) for these lots of tungsten are presented for the range 4 to 3000 0 K

Recent Developments in the NIST Atomic Databases

Science.gov (United States)

Kramida, Alexander

2011-05-01

New versions of the NIST Atomic Spectra Database (ASD, v. 4.0) and three bibliographic databases (Atomic Energy Levels and Spectra, v. 2.0, Atomic Transition Probabilities, v. 9.0, and Atomic Line Broadening and Shapes, v. 3.0) have recently been released. In this contribution I will describe the main changes in the way users get the data through the Web. The contents of ASD have been significantly extended. In particular, the data on highly ionized tungsten (W III-LXXIV) have been added from a recently published NIST compilation. The tables for Fe I and Fe II have been replaced with newer, much more extensive lists (10000 lines for Fe I). The other updated or new spectra include H, D, T, He I-II, Li I-III, Be I-IV, B I-V, C I-II, N I-II, O I-II, Na I-X, K I-XIX, and Hg I. The new version of ASD now incorporates data on isotopes of several elements. I will describe some of the issues the NIST ASD Team faces when updating the data.

Recent Developments in the NIST Atomic Databases

International Nuclear Information System (INIS)

Kramida, Alexander

2011-01-01

New versions of the NIST Atomic Spectra Database (ASD, v. 4.0) and three bibliographic databases (Atomic Energy Levels and Spectra, v. 2.0, Atomic Transition Probabilities, v. 9.0, and Atomic Line Broadening and Shapes, v. 3.0) have recently been released. In this contribution I will describe the main changes in the way users get the data through the Web. The contents of ASD have been significantly extended. In particular, the data on highly ionized tungsten (W III-LXXIV) have been added from a recently published NIST compilation. The tables for Fe I and Fe II have been replaced with newer, much more extensive lists (10000 lines for Fe I). The other updated or new spectra include H, D, T, He I-II, Li I-III, Be I-IV, B I-V, C I-II, N I-II, O I-II, Na I-X, K I-XIX, and Hg I. The new version of ASD now incorporates data on isotopes of several elements. I will describe some of the issues the NIST ASD Team faces when updating the data.

Neutron activation analysis of NBS oyster tissue (SRM 1566) and IAEA animal bone (H-5)

International Nuclear Information System (INIS)

Lepel, E.A.; Laul, J.C.

1984-03-01

Instrumental and radiochemical neutron activation analysis (INAA and RNAA) were employed to measure about 37 major, minor, and trace elements in two standard reference materials: oyster tissue (SRM 1566) supplied by the National Bureau of Standards (NBS) and animal bone (H-5) supplied by the International Atomic Energy Agency (IAEA). Wherever the comparison exists, our data show excellent agreement with accepted values for each SRM. These SRM's are useful as reference standards for the analysis of biological materials. Additionally, the chondritic normalized rare earth element pattern of animal bone behaves as a smooth function of the ionic radii, as previously observed for biological materials

Heat-assisted aqueous extraction of rice flour for arsenic speciation analysis.

Science.gov (United States)

Narukawa, Tomohiro; Chiba, Koichi

2010-07-28

A versatile heat-assisted pretreatment aqueous extraction method for the analysis of arsenic species in rice was developed. Rice flour certified reference materials NIST SRM1568a and NMIJ CRM 7503-a and a flour made from polished rice were used as samples, and HPLC-ICP-MS was employed for the determination of arsenic species. Arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) were detected in NIST SRM, and As(III), As(V) and DMAA were found in NMIJ CRM and the prepared polished rice flour. The sums of the concentrations of all species in each rice flour sample were 97-102% of the total arsenic concentration in each sample.

Calculation of radioactivity of β-nuclides by CIEMAT/NIST method

International Nuclear Information System (INIS)

Shu Fujun; Zhang Shengdong; Ding Youqian; Sun Hongqing; Tang Peijia

2010-01-01

CIEMAT/NIST method for calculating radioactivity of β-nuclides was introduced in this paper. The influences of KB value and quenching parameter on the radioactivity computation of 241 Pu, 106 Ru/ 106 Rh, 63 Ni, 151 Sm and 14 C were studied by CIEMAT/NIST method with 3 H tracing. It is shown that the effect of KB value can be ignored if it varies in a proper range; Except for 106 Ru/ 106 Rh, the discrepancy between prediction and actual activity is lower than 2% in low quenching extent. However, it increases with quenching extent, and the largest discrepancy soars to nearly 13%. In addition, the reason for bad agreement of 106 Ru/ 106 Rh between prediction and actual activity was discussed. Efficiency calibration curves of 79 Se, 93 Zr and 107 Pd were also computed by CIEMAT/NIST method, compared with approximate replacement method or fitting and interpolation method. It is shown that CIEMAT/NIST method is no more accurate and suitable than the other two techniques. (authors)

R dump converter without DC link capacitor for an 8/6 SRM: experimental investigation.

Science.gov (United States)

Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

2015-01-01

The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.

A response to: "NIST experts urge caution in use of courtroom evidence presentation method"

OpenAIRE

Morrison, Geoffrey Stewart

2017-01-01

A press release from the National Institute of Standards and Technology (NIST)could potentially impede progress toward improving the analysis of forensic evidence and the presentation of forensic analysis results in courts in the United States and around the world. "NIST experts urge caution in use of courtroom evidence presentation method" was released on October 12, 2017, and was picked up by the phys.org news service. It argues that, except in exceptional cases, the results of forensic ana...

Hg0 and HgCl2 Reference Gas Standards: ?NIST Traceability ...

Science.gov (United States)

EPA and NIST have collaborated to establish the necessary procedures for establishing the required NIST traceability of commercially-provided Hg0 and HgCl2 reference generators. This presentation will discuss the approach of a joint EPA/NIST study to accurately quantify the true concentrations of Hg0 and HgCl2 reference gases produced from high quality, NIST-traceable, commercial Hg0 and HgCl2 generators. This presentation will also discuss the availability of HCl and Hg0 compressed reference gas standards as a result of EPA's recently approved Alternative Methods 114 and 118. Gaseous elemental mercury (Hg0) and oxidized mercury (HgCl2) reference standards are integral to the use of mercury continuous emissions monitoring systems (Hg CEMS) for regulatory compliance emissions monitoring. However, a quantitative disparity of approximately 7-10% has been observed between commercial Hg0 and HgCl2 reference gases which currently limits the use of (HgCl2) reference gas standards. Resolving this disparity would enable the expanded use of (HgCl2) reference gas standards for regulatory compliance purposes.

Ultra-micro trace element contents in spices from Sri Lanka

International Nuclear Information System (INIS)

Chery, C.C.; Herremans, S.; Van Lierde, V.; Vanhaecke, F.; Jasekera, R.

2008-01-01

Spices were analyzed by ICP-MS for determination of the ultra-micro trace elements in the human adult, Bi, Cd, Co, Ni, Pd, Pt, Se, Sn, Te, Tl, to complement previous results obtained by INAA and by EDXRF. The spices, originating from Sri Lanka, were curry, chilli powder and turmeric powders, coriander, cinnamon, black pepper, fennel, rampeh and curry leaves, and cumin. The analytical procedure was validated by analyzing the certified reference materials NIST SRM 1572 Citrus Leaves and NIST SRM 1573 Tomato Leaves. The results indicate that spices may contribute well to the daily optimal uptake of nutrients of a human adult. The adequacy of spices as a reference material with certified ultra micro trace elements is suggested. (author)

NIST/ASME Steam Properties Database

Science.gov (United States)

SRD 10 NIST/ASME Steam Properties Database (PC database for purchase)   Based upon the International Association for the Properties of Water and Steam (IAPWS) 1995 formulation for the thermodynamic properties of water and the most recent IAPWS formulations for transport and other properties, this updated version provides water properties over a wide range of conditions according to the accepted international standards.

Chemical characterization of diets consumed in the COSEAS restaurant, by neutron activation analysis

International Nuclear Information System (INIS)

Favaro, Deborah I.T.; Chioccola, Gabriella S.; Bortoli, Maritsa C.; Cozzolino, Silvia M.F.

2005-01-01

This study presents the results of chemical characterization of meals (lunch) offered by COSEAS/USP-SP restaurant, during 5 non consecutive days. These meals were collected in triplicate, in the same way they are offered to the users, being freeze-dried and prepared for chemical analysis. In the total, 15 samples were collected. The proximate composition was determined by using the standard methodologies according to AOAC (1995). The contents of some micronutrients (Ca, Fe, K, Na, Se and Zn) were determined by instrumental neutron activation analysis. The methodology validation was performed by certified reference materials analyses: Oyster Tissue (NIST SRM 1566 b ), Orchard Leaves (NIST SRM 1541) and Peach Leaves (NIST SRM 1547). >From concentration results the daily intake of each micronutrient was calculated considering this meal as 40% of the total daily intake and the values were compared to the new dietary recommendations of micronutrients (Dietary Reference Intakes-DRIs, Institute of Medicine, USA), for the women in the life stage from 19 to 30 years. Comparing the average values found with the recommended values, it was verified that macronutrients and Fe, Se and Zn micronutrients reached the values set by new DRIs. For Ca and K the daily intake was inadequate and Na, exceeded the recommended value. (author)

Chemical characterization of diets consumed in the COSEAS restaurant, by neutron activation analysis; Caracterizacao quimica de dietas consumidas no restaurante do COSEAS/USP-SP, por ativacao neutronica

Energy Technology Data Exchange (ETDEWEB)

Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica]. E-mail: defavaro@ipen.br; Chioccola, Gabriella S.; Bortoli, Maritsa C.; Cozzolino, Silvia M.F. [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Alimentos e Nutricao Experimental]. E-mail: gabich@usp.br

2005-07-01

This study presents the results of chemical characterization of meals (lunch) offered by COSEAS/USP-SP restaurant, during 5 non consecutive days. These meals were collected in triplicate, in the same way they are offered to the users, being freeze-dried and prepared for chemical analysis. In the total, 15 samples were collected. The proximate composition was determined by using the standard methodologies according to AOAC (1995). The contents of some micronutrients (Ca, Fe, K, Na, Se and Zn) were determined by instrumental neutron activation analysis. The methodology validation was performed by certified reference materials analyses: Oyster Tissue (NIST SRM 1566{sup b}), Orchard Leaves (NIST SRM 1541) and Peach Leaves (NIST SRM 1547). >From concentration results the daily intake of each micronutrient was calculated considering this meal as 40% of the total daily intake and the values were compared to the new dietary recommendations of micronutrients (Dietary Reference Intakes-DRIs, Institute of Medicine, USA), for the women in the life stage from 19 to 30 years. Comparing the average values found with the recommended values, it was verified that macronutrients and Fe, Se and Zn micronutrients reached the values set by new DRIs. For Ca and K the daily intake was inadequate and Na, exceeded the recommended value. (author)

LA-ICP-MS of magnetite: Methods and reference materials

Science.gov (United States)

Nadoll, P.; Koenig, A.E.

2011-01-01

Magnetite (Fe3O4) is a common accessory mineral in many geologic settings. Its variable geochemistry makes it a powerful petrogenetic indicator. Electron microprobe (EMPA) analyses are commonly used to examine major and minor element contents in magnetite. Laser ablation ICP-MS (LA-ICP-MS) is applicable to trace element analyses of magnetite but has not been widely employed to examine compositional variations. We tested the applicability of the NIST SRM 610, the USGS GSE-1G, and the NIST SRM 2782 reference materials (RMs) as external standards and developed a reliable method for LA-ICP-MS analysis of magnetite. LA-ICP-MS analyses were carried out on well characterized magnetite samples with a 193 nm, Excimer, ArF LA system. Although matrix-matched RMs are sometimes important for calibration and normalization of LA-ICP-MS data, we demonstrate that glass RMs can produce accurate results for LA-ICP-MS analyses of magnetite. Cross-comparison between the NIST SRM 610 and USGS GSE-1G indicates good agreement for magnetite minor and trace element data calibrated with either of these RMs. Many elements show a sufficiently good match between the LA-ICP-MS and the EMPA data; for example, Ti and V show a close to linear relationship with correlation coefficients, R2 of 0.79 and 0.85 respectively. ?? 2011 The Royal Society of Chemistry.

Resorting the NIST undulator using simulated annealing for field error reduction

International Nuclear Information System (INIS)

Denbeaux, Greg; Johnson, Lewis E.; Madey, John M.J.

2000-01-01

We have used a simulated annealing algorithm to sort the samarium cobalt blocks and vanadium permendur poles in the hybrid NIST undulator to optimize the spectrum of the emitted light. While simulated annealing has proven highly effective in sorting of the SmCo blocks in pure REC undulators, the reliance on magnetically 'soft' poles operating near saturation to concentrate the flux in hybrid undulators introduces a pair of additional variables - the permeability and saturation induction of the poles - which limit the utility of the assumption of superposition on which most simulated annealing codes rely. Detailed magnetic measurements clearly demonstrated the failure of the superposition principle due to random variations in the permeability in the 'unsorted' NIST undulator. To deal with the issue, we measured both the magnetization of the REC blocks and the permeability of the NIST's integrated vanadium permendur poles, and implemented a sorting criteria which minimized the pole-to-pole variations in permeability to satisfy the criteria for realization of superposition on a nearest-neighbor basis. Though still imperfect, the computed spectrum of the radiation from the re-sorted and annealed NIST undulator is significantly superior to that of the original, unsorted device

Determination of ultratrace levels of mercury in three SRMs by combustion RNAA

International Nuclear Information System (INIS)

Norman, B.R.; Becker, D.A.

2000-01-01

A radiochemical neutron activation analysis (RNAA) combustion method coupled with a neutron exposure normalization technique was used to determine low μg/kg mercury levels in three National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs). Two coals (sub-bituminous and bituminous) and a diet material were analyzed. The results obtained provided recommended values of approximately 5 μg/kg for SRM 1548a Typical Diet, 24 μg/kg for SRM 1635 Trace Elements in Coal (sub-bituminous), and 100 μg/kg for SRM 1632b Trace Elements in Coal (bituminous). (author)

Analysis of Serum Total and Free PSA Using Immunoaffinity Depletion Coupled to SRM: Correlation with Clinical Immunoassay Tests

Science.gov (United States)

Liu, Tao; Hossain, Mahmud; Schepmoes, Athena A.; Fillmore, Thomas L.; Sokoll, Lori J.; Kronewitter, Scott R.; Izmirlian, Grant; Shi, Tujin; Qian, Wei-Jun; Leach, Robin J.; Thompson, Ian M.; Chan, Daniel W.; Smith, Richard D.; Kagan, Jacob; Srivastava, Sudhir; Rodland, Karin D.; Camp, David G.

2012-01-01

Recently, selected reaction monitoring mass spectrometry (SRM-MS) has been more frequently applied to measure low abundance biomarker candidates in tissues and biofluids, owing to its high sensitivity and specificity, simplicity of assay configuration, and exceptional multiplexing capability. In this study, we report for the first time the development of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. Low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed good correlation in several independent clinical serum sample sets. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring candidate biomarkers in human blood, without the need to develop affinity reagents. Furthermore, the simultaneous measurement of multiple biomarkers, including the free and bound forms of PSA, can be performed in a single multiplexed analysis using high-resolution liquid chromatographic separation coupled with SRM-MS. PMID:22846433

NIST: Information Management in the AMRF

Science.gov (United States)

Callaghan, George (Editor)

1991-01-01

The information management strategies developed for the NIST Automated Manufacturing Research Facility (AMRF) - a prototype small batch manufacturing facility used for integration and measurement related standards research are outlined in this video. The five major manufacturing functions - design, process planning, off-line programming, shop floor control, and materials processing are explained and their applications demonstrated.

Marine mammal blubber reference and control materials for use in the determination of halogenated organic compounds and fatty acids

Energy Technology Data Exchange (ETDEWEB)

Kucklick, John R.; Pugh, Rebecca S.; Becker, Paul R. [Hollings Marine Laboratory, National Institute of Standards and Technology (NIST), Charleston, SC (United States); Schantz, Michele M.; Porter, Barbara J.; Poster, Dianne L.; Leigh, Stefan; Wise, Stephen A. [NIST, Analytical Chemistry Division, Gaithersburg, MD (United States); Rowles, Teri K. [National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Silver Spring, MD (United States)

2010-05-15

The National Institute of Standards and Technology (NIST) has a diverse collection of control materials derived from marine mammal blubber, fat, and serum. Standard Reference Material (SRM) 1945 Organics in Whale Blubber was recertified for polychlorinated biphenyl (PCB) congeners, organochlorine pesticides, and polybrominated diphenyl ether (PBDE) congeners. SRM 1945 has also been assigned mass fraction values for compounds not frequently determined in marine samples including toxaphene congeners, coplanar PCBs, and methoxylated PBDE congeners which are natural products. NIST also has assigned mass fraction values, as a result of interlaboratory comparison exercises, for PCB congeners, organochlorine pesticides, PBDE congeners, and fatty acids in six homogenate materials produced from marine mammal blubber or serum. The materials are available from NIST upon request; however, the supply is very limited for some of the materials. The materials include those obtained from pilot whale blubber (Homogenates III and IV), Blainville's beaked whale blubber (Homogenate VII), polar bear fat (Homogenate VI), and California sea lion serum (Marine Mammal Control Material-1 Serum) and blubber (Homogenate V). (orig.)

Individual carotenoid content of SRM 1548 total diet and influence of storage temperature, lyophilization, and irradiation on dietary carotenoids

International Nuclear Information System (INIS)

Craft, N.E.; Wise, S.A.

1993-01-01

A modified version of the AOAC procedure for the extraction of carotenoids from mixed feeds was coupled with an isocratic reversed-phase liquid chromatography (LC) method to measure individual carotenoids in SRM 1548 total diet and in a high-carotenoid mixed diet (HCMD). The major carotenoids identified in SRM 1548 were lycopene, beta-carotene, lutein, alpha-carotene, and zeaxanthin in descending order of concentration. The concentration of all carotenoids in SRM 1548 decreased as storage temperature increased. Significant differences in carotenoid concentrations occurred between -80 and 4 degrees C storage temperatures. Lyophilization of the HCMD significantly decreased beta-carotene and lycopene concentrations and produced an apparent increase in xanthophyll concentrations. Exposure to gamma-irradiation significantly decreased alpha-carotene and beta-carotene concentrations and led to an apparent increase in P-cryptoxanthin. SRM 1548 was found to be unsuitable for use as a reference material for carotenoid measurements, while HCMD has greater potential as a reference material

NBS SRM 1569 Brewer's Yeast: Is it an adequate standard reference material for testing a chromium determination in biological materials tion in biological materials

International Nuclear Information System (INIS)

Goeij, J.J.M. de; Volkers, K.J.; Tjioe, P.S.; Kroon, J.J.

1978-01-01

Some analytical experiences with NBS SRM 1569 Brewer's Yeast are presented. Against this background the adequacy of this standard reference material for the determination of chromium in biological materials is discussed. Authors have three main objections. Due to its high content of insoluble chromium-containing particles, SRM 1569 is not typical for biological materials, possibly not even for Brewer's Yeast. The chromium level of SRM 1569 is not typical for the chromium levels normally encountered in pure biological materials. The major fraction (69 +- 3 percent) of the chromium is present in a form which is insoluble under the conditions used in Author's analysis. (T.I.)

ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

Energy Technology Data Exchange (ETDEWEB)

Beals, D.

2011-12-06

Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.

Use of INAA in the preparation of a set soil Reference Materials with certified values of total element contents

International Nuclear Information System (INIS)

Kucera, J.; Horakova, J.; Soukal, L.

1997-01-01

A set of certified Reference Materials was prepared consisting of four natural agricultural soils with normal (n) and elevated (e) levels of element contents: CRM 7001 Light Sandy Soil (n), CRM 7002 Light Sandy Soil (e), CRM 7003 Silty Clay Loam (n), and CRM 7004 Loam (e). In these materials, certified and/or information values of the total contents of the elements As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, V and Zn, and their fractions extractable by aqua regia, boiling and cold 2M nitric acid were derived from an interlaboratory comparison in which 28 laboratories participated. Highly precise and accurate procedures of instrumental neutron activation analysis (INAA) were employed for homogeneity testing and also for certification of the total element contents. For comparation purposes, NIST SRM-2704 Buffalo River Sediment was analyzed by INAA, as well. The INAA results obtained compared very well with the certified and/or information values for four soil CRMs and also with NIST values for SRM-2704. From this agreement, a very high reliability of the new soil CRMs can be inferred. (author)

SRM, motor para el desarrollo de la cadena de valor Supplier Relationship Management – SRM gestión de las relaciones con los proveedores

Directory of Open Access Journals (Sweden)

Luis Leonardo Mendoza S.

2010-01-01

Ejemplo de ello es el SRM, Supplier Relationship Management, en donde por medio de la constitución de acuerdos basados en intereses comunes, se establecen relaciones estrechas, funcionales y eficientes entre las partes, permitiendo por esta vía la garantía del suministro, y de esta forma, darle un importante impulso para el desarrollo de la cadena de valor.

NIST Accelerator Facilities And Programs In Support Of Industrial Radiation Research

International Nuclear Information System (INIS)

Bateman, F.B.; Desrosiers, M.F.; Hudson, L.T.; Coursey, B.M.; Bergstrom, P.M. Jr.; Seltzer, S.M.

2003-01-01

NIST's Ionizing Radiation Division maintains and operates three electron accelerators used in a number of applications including waste treatment and sterilization, radiation hardness testing, detector calibrations and materials modification studies. These facilities serve a large number of governmental, academic and industrial users as well as an active intramural research program. They include a 500 kV cascaded-rectifier accelerator, a 2.5 MV electron Van de Graaff accelerator and a 7 to 32 MeV electron linac, supplying beams ranging in energy from a few keV up to 32 MeV. In response to the recent anthrax incident, NIST along with the US Postal Service and the Armed Forces Radiobiology Research Institute (AFRRI) are working to develop protocols and testing procedures for the USPS mail sanitization program. NIST facilities and personnel are being employed in a series of quality-assurance measurements for both electron- and photon-beam sanitization. These include computational modeling, dose verification and VOC (volatile organic compounds) testing using megavoltage electron and photon sources

76 FR 43264 - Proposed Information Collection; Comment Request; NIST MEP Client Impact Survey

Science.gov (United States)

2011-07-20

... DEPARTMENT OF COMMERCE National Institute of Standards and Technology Proposed Information Collection; Comment Request; NIST MEP Client Impact Survey AGENCY: National Institute of Standards and Technology (NIST), Commerce. ACTION: Notice. SUMMARY: The Department of Commerce, as part of its continuing...

Ground To Flight Extrapolation Of SRM Radiative Loads

Science.gov (United States)

Ferrara, V.; Paglia, F.; Mogavero, A.; Genito, M.; Bonnet, M.

2011-05-01

VEGA is a European launch vehicle under development by the Prime Contractor ELV S.p.A. in the frame of an ESA Contract. It is constituted by four stages, dedicated to the scientific/commercial market of small satellites (300 ÷ 2500 kg) into Low Earth Orbits, with inclinations ranging from 5.2° up to Sun Synchronous Orbits and with altitude ranging from 300 to 1500 km. In the framework of the development of the VEGA Launch vehicle a great effort has been spent in the development of all the three SRMs powering the LV. Even if this development is really challenging on the other hand a great amount of experimental data coming from SRM firing tests is available. Taking benefit of the up to date CFD methodology and of the existence of experimental data a verification/validation activity has been performed by Avio S.p.A. and ELV S.p.A., aimed at the estimation of in-flight radiative loads coming from the VEGA Solid Rocket motors. Numerical simulations have been performed by means of the multi-purpose code FLUENT 6.3 ® under the hypothesis of a steady state approach considering a turbulent flow. A multiphase numerical approach has been also developed and validated against experimental data coming from the bench firing tests showing a good level of numerical accuracy (1Fig.1). The study of the Vega motors plume has been identified in the class of dispersed flows, with the typical regime of particulate flow in which has been identified the configuration of solid particles in gas. The selected approach is two way coupled Eulerian-Lagrangian. The Navier-Stokes equations, including source term to take into account the presence of particulate, are solved at each time-step in conjunction with the radiation equation and particulate motion law and heat-transfer equations. The resulting system of equations is a fully coupled system solved with an explicit algorithm. The methodology, and particularly radiation properties settings, has been verified against available experimental

One cubic metre NIST traceable radon test chamber

International Nuclear Information System (INIS)

Kotrappa, P.; Stieff, F.

2008-01-01

With the availability of the National Inst. of Standards and Technology (NIST) Radon Emanation Standard with a content of ∼5000 Bq of 226 Ra, it is possible to build a flow through a practical radon test chamber. A standard glove box with four gloves and a transfer port is used. Air is pumped through a flow integrator, water jar for humidification and NIST source holder, and into the glove box through a manifold. A derived theoretical expression provides the calculated radon concentration inside the chamber. The calculation includes a derived decay correction due to the large volume and low flow rate of the system. Several calibrated continuous radon monitors and passive integrating electret ion chambers tested in the chamber agreed fairly well with the calculated radon concentrations. The chamber is suitable for handling the calibration of several detectors at the same time. (authors)

Determination of essential and toxic elements in commercial baby foods by instrumental neutron activation analysis and atomic absorption spectrometry; Determinacao dos elementos essenciais e toxicos em alimentos comerciais infantis por analise por ativacao com neutrons e espectrometria de absorcao atomica

Energy Technology Data Exchange (ETDEWEB)

Vallinoto, Priscila

2013-08-01

The World Health Organization recommends that infants should be breast fed exclusively for at least six months after birth. After this period, it is recommended to start introducing complementary foods, in order to meet the child's nutritional, mineral and energy needs. Commercial food products for infants form an important part of the diet for many babies. Thus, it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of infant malnutrition in developing countries. In this study, essential elements: Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, Se and Zn and toxic elements: As, Cd, Hg levels were determined in twenty seven different commercial infant food product samples by Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS). In order to validate both methodologies the reference material: INCT MPH-2 Mixed Polish Herbs and NIST - SRM 1577b Bovine Liver by INAA and NIST - SRM 1548th Typical Diet and NIST - SRM 1547 Peach Leaves by AAS were analyzed. The twenty seven baby food samples were acquired from Sao Paulo city supermarkets and stores. Essential and toxic elements were determined. Most of the essential element concentrations obtained were lower than the World Health Organization requirements, while concentrations of toxic elements were below the tolerable upper limit. These low essential element concentrations in these samples indicate that infants should not be fed only with commercial complementary foods. (author)

Determination of essential and toxic elements in commercial baby foods by instrumental neutron activation analysis and atomic absorption spectrometry

International Nuclear Information System (INIS)

Vallinoto, Priscila

2013-01-01

The World Health Organization recommends that infants should be breast fed exclusively for at least six months after birth. After this period, it is recommended to start introducing complementary foods, in order to meet the child's nutritional, mineral and energy needs. Commercial food products for infants form an important part of the diet for many babies. Thus, it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of infant malnutrition in developing countries. In this study, essential elements: Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, Se and Zn and toxic elements: As, Cd, Hg levels were determined in twenty seven different commercial infant food product samples by Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS). In order to validate both methodologies the reference material: INCT MPH-2 Mixed Polish Herbs and NIST - SRM 1577b Bovine Liver by INAA and NIST - SRM 1548th Typical Diet and NIST - SRM 1547 Peach Leaves by AAS were analyzed. The twenty seven baby food samples were acquired from Sao Paulo city supermarkets and stores. Essential and toxic elements were determined. Most of the essential element concentrations obtained were lower than the World Health Organization requirements, while concentrations of toxic elements were below the tolerable upper limit. These low essential element concentrations in these samples indicate that infants should not be fed only with commercial complementary foods. (author)

HAPPY Team Entry to NIST OpenSAD Challenge

DEFF Research Database (Denmark)

Kinnunen, Tomi; Sholokhov, Alexey; Khoury, Elie

2016-01-01

Speech activity detection (SAD), the task of locating speech segments from a given recording, remains challenging under acoustically degraded conditions. In 2015, National Institute of Standards and Technology (NIST) coordinated OpenSAD bench-mark. We summarize “HAPPY” team effort to Open- SAD...

Development and validation of an analytical method for the determination of lead isotopic composition using ICP-QMS

OpenAIRE

Rodríguez-Salazar, M. T.; Morton Bermea, O.; Hernández-Álvarez, E.; García-Arreola, M. E.; Ortuño-Arzate, M. T.

2010-01-01

This work reports a method for the precise and accurate determination of Pb isotope composition in soils and geological matrices by ICP-QMS. Three reference materials (AGV-2, SRM 2709 and JSO-1) were repeatedly measured, using ICP-QMS instruments in order to assess the quality of this analytical procedure. Mass discrimination was evaluated for Pb/Pb with Pb isotope reference material NIST SRM 981, and the correction applied to the above mentioned reference materials to achieve good accuracy o...

77 FR 40586 - Draft NIST Interagency Report (NISTIR) 7823, Advanced Metering Infrastructure Smart Meter...

Science.gov (United States)

2012-07-10

...-01] Draft NIST Interagency Report (NISTIR) 7823, Advanced Metering Infrastructure Smart Meter... Technology (NIST) seeks comments on Draft NISTIR 7823, Advanced Metering Infrastructure Smart Meter... conformance test requirements for the firmware upgradeability process for the Advanced Metering Infrastructure...

Determination of non-ortho polychlorinated biphenyls in environmental Standard Reference Materials.

Science.gov (United States)

Brubaker, W W; Schantz, M M; Wise, S A

2000-07-01

The concentrations of three non-ortho ("coplanar") polychlorinated biphenyls, 3,3',4,4'-tetrachlorobiphenyl (IUPAC PCB 77), 3,3',4,4',5-pentachlorobiphenyl (IUPAC PCB 126), and 3,3',4,4',5,5'-hexachlorobiphenyl (IUPAC PCB 169), were determined in five NIST Standard Reference Materials (SRMs) of environmental and biological interest. The measured levels were approximately between (0.2 to 1.3) ng/g in SRM 1588a (Organics in Cod Liver Oil), (0.3 to 9) ng/g in SRM 1944 (New York/New Jersey Waterway Sediment), (0.2 to 0.4) ng/g in SRM 1945 (Organics in Whale Blubber), (1 to 18) ng/g in SRM 2974 (Organics in Freeze-dried Mussel Tissue [Mytilus edulis]), and (0.1 to 0.4) ng/g in candidate SRM 1946 (Lake Superior Fish Tissue). PCB 169 was present at < 0.1 ng/g in SRMs 1944 and 2974.

Analysis of Serum Total and Free PSA Using Immunoaffinity Depletion Coupled to SRM: Correlation with Clinical Immunoassay Tests

Energy Technology Data Exchange (ETDEWEB)

Liu, Tao; Hossain, Mahmud; Schepmoes, Athena A.; Fillmore, Thomas L.; Sokoll, Lori J.; Kronewitter, Scott R.; Izmirlian, Grant; Shi, Tujin; Qian, Weijun; Leach, Robin; Thompson, Ian M.; Chan, Daniel W.; Smith, Richard D.; Kagan, Jacob; Srinivastava, Sudhir; Rodland, Karin D.; Camp, David G.

2012-08-03

Sandwich immunoassay is the standard technique used in clinical labs for quantifying protein biomarkers for disease detection, monitoring and therapeutic intervention. Albeit highly sensitive, the development of a specific immunoassay is rather time-consuming and associated with extremely high cost due to the requirement for paired immunoaffinity reagents of high specificity. Recently, mass spectrometry-based methods, specifically selected reaction monitoring mass spectrometry (SRM-MS), have been increasingly applied to measure low abundance biomarker candidates in tissue and biofluids, owing to high sensitivity and specificity, simplicity of assay configuration, and great multiplexing capability. In this study, we report for the first time the development of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. With stable isotope dilution and external calibration, low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed very good correlation (R2 values ranging from 0.90 to 0.99) in several independent clinical serum sample sets, including a set of 33 samples assayed in a blinded test. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring total and free PSA in human blood. Furthermore, simultaneous measurement of free and total PSA and many other biomarkers can be performed in a single analysis using high-resolution liquid chromatographic separation coupled with SRM-MS.

Establishment of a sensor testbed at NIST for plant productivity monitoring

Science.gov (United States)

Allen, D. W.; Hutyra, L.; Reinmann, A.; Trlica, A.; Marrs, J.; Jones, T.; Whetstone, J. R.; Logan, B.; Reblin, J.

2017-12-01

Accurate assessments of biogenic carbon fluxes is challenging. Correlating optical signatures to plant activity allows for monitoring large regions. New methods, including solar-induced fluorescence (SIF), promise to provide more timely and accurate estimate of plant activity, but we are still developing a full understanding of the mechanistic leakage between plant assimilation of carbon and SIF. We have initiated a testbed to facilitate the evaluation of sensors and methods for remote monitoring of plant activity at the NIST headquarters. The test bed utilizes a forested area of mature trees in a mixed urban environment. A 1 hectare plot within the 26 hectare forest has been instrumented for ecophysiological measurements with an edge (100 m long) that is persistently monitored with multimodal optical sensors (SIF spectrometers, hyperspectral imagers, thermal infrared imaging, and lidar). This biological testbed has the advantage of direct access to the national scales maintained by NIST of measurements related to both the physical and optical measurements of interest. We offer a description of the test site, the sensors, and preliminary results from the first season of observations for ecological, physiological, and remote sensing based estimates of ecosystem productivity.

Applied research on environmental pollution using INAA. A study on the environmental indicator analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Nak Bae; Lee, Gil Yong; Yoon, Yoon Yul; Chon, Sang Ki [Korea Institute of Geology Mining and Research, Taejon (Korea, Republic of)

1995-08-01

Among the many kinds of environmental indicator samples such as moss, lichen, pine needle, pine needle was selected as a bio-monitor and collected sample was divided two groups and one was washed with 1% hydrochloric acid to remove the elements deposited on surface. Trace elements in pine needle were analyzed by the decay time of each nuclide. Analytical accuracy was tested by analyzing NIST SRM 1575 pine needle. Results are follows: (1) Environmental indicator as a bio-monitor pine needle was selected. (2) The content difference of the trace elements between sampling period was monitored. And as content was varied with sampling time. (3) To monitor the influence of atmospheric deposition the surface of pine needle was washed with 1% hydrochloric acid. Therefore, As, Ce, La, Na, W, and Zn contents were decreased by washing. (4) Non-destructive INAA (Instrumental Neutron Activation Analysis) technique was developed for the determination of trace elements in environmental samples. (5) Analytical accuracy was tested by analyzing NIST SRM 1575 pine needle, and the accuracy was well agreed within 10% deviation. summarized. (author). 18 refs., 8 figs., 5 tabs.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Science.gov (United States)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Preliminary assessment of trace elements effects on essential oil production of Melissa officinalis L. (Lemon balm)

International Nuclear Information System (INIS)

Sussa, Fabio V.; Duarte, Celina L.; Andrade, Luana S.; Silva, Paulo S.C.; Furlan, Marcos R.

2013-01-01

Melissa officinalis L., Lemon balm, (Lamiaceae) is an herb used as medicine, condiment and in the cosmetic and perfumery industry due to its essential oil. In this study a preliminary assessment of trace elements effects on essential oil production was performed in order to verify an improvement in its quality. The Melissa officinalis samples were harvested from three different soil sites localized in Ibirapuera Park, São Paulo, Brazil. Elemental concentration for the elements As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Ti, Th, U, V, Yb, Zn and Zr was determined by Instrumental Neutron Activation Analysis (INAA) in Melissa officinalis leaves and surrounding soil. The essential oil was extracted from its leaves by hydrodistillation process in Clevenger apparatus and analyzed by gas chromatography coupled to a mass spectrometer (GC-MS). Certified reference materials NIST SRM-1515 Apple Leaves, NIST SRM-1547 Peach Leaves and NIST SRM-1573a Tomato Leaves were analyzed for quality control. Our results showed Geranial and Neral were identified as the major compounds in the essential oil extracted from Melissa officinalis L. for all collected sites. However, the relative proportion of some chemical constituents was altered according to the site collected. The preliminary results showed that the production of essential oil by Melissa officinalis must be positively correlated with the concentrations of Rb, Zn and negatively correlated with Sc, Mn, La, K, Fe, and Cr. (author)

Preliminary assessment of trace elements effects on essential oil production of Melissa officinalis L. (Lemon balm)

Energy Technology Data Exchange (ETDEWEB)

Sussa, Fabio V.; Duarte, Celina L.; Andrade, Luana S.; Silva, Paulo S.C., E-mail: pscsilva@ipen.br, E-mail: clduarte@ipen.br, E-mail: fabiosussa@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Furlan, Marcos R., E-mail: furlanagro@gmail.com [Universidade de Taubate, SP (Brazil). Departamento de Ciencias Agrarias

2013-07-01

Melissa officinalis L., Lemon balm, (Lamiaceae) is an herb used as medicine, condiment and in the cosmetic and perfumery industry due to its essential oil. In this study a preliminary assessment of trace elements effects on essential oil production was performed in order to verify an improvement in its quality. The Melissa officinalis samples were harvested from three different soil sites localized in Ibirapuera Park, São Paulo, Brazil. Elemental concentration for the elements As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Ti, Th, U, V, Yb, Zn and Zr was determined by Instrumental Neutron Activation Analysis (INAA) in Melissa officinalis leaves and surrounding soil. The essential oil was extracted from its leaves by hydrodistillation process in Clevenger apparatus and analyzed by gas chromatography coupled to a mass spectrometer (GC-MS). Certified reference materials NIST SRM-1515 Apple Leaves, NIST SRM-1547 Peach Leaves and NIST SRM-1573a Tomato Leaves were analyzed for quality control. Our results showed Geranial and Neral were identified as the major compounds in the essential oil extracted from Melissa officinalis L. for all collected sites. However, the relative proportion of some chemical constituents was altered according to the site collected. The preliminary results showed that the production of essential oil by Melissa officinalis must be positively correlated with the concentrations of Rb, Zn and negatively correlated with Sc, Mn, La, K, Fe, and Cr. (author)

Determination of polychlorinated dibenzo-p-dioxin and dibenzofuran congeners in air particulate and marine sediment standard reference materials (SRMs).

Science.gov (United States)

Chiu, C H; Turle, R; Poole, G; Thibert, B; Brubaker, W W; Schantz, M M; Wise, S A

2001-02-01

Due to the limited number of environmental matrix certified reference materials (CRMs) with assigned values for natural levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), an interlaboratory study was undertaken by the National Institute of Standards and Technology (NIST) and Environment Canada to establish reference concentration values for selected PCDD/Fs in two well-characterized NIST Standard Reference Materials (SRMs): SRM 1649a (Urban Dust) and SRM 1944 (New York/New Jersey Waterway Sediment). Results from 14 laboratories were used to provide reference values for the seventeen 2, 3, 7, 8-substituted PCDD/F congeners, the totals for individual tetra- through hepta-substituted PCDD/F homologues, and the total amount of tetra- through hepta-substituted PCDD/Fs. The mass fractions for the individual 2, 3, 7, 8-substituted congeners range from approximately 0.01 microg/kg to 7 microg/kg dry mass.

Instrumental neutron activation analysis of rib bone samples and of bone reference materials

International Nuclear Information System (INIS)

Saiki, M.; Takata, M.K.; Kramarski, S.; Borelli, A.

2000-01-01

The instrumental neutron activation analysis method was used for the determination of trace elements in rib bone samples taken from autopsies of accident victims. The elements Br, Ca, Cl, Cr, Fe, Mg, Mn, Na, P, Sr, Rb and Zn were determined in cortical tissues by using short and long irradiations with thermal neutron flux of the IEA-R1m nuclear reactor. The reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were also analyzed in order to evaluate the precision and the accuracy of the results. It was verified that lyophilization is the most convenient process for drying bone samples since it does not cause any element losses. Comparisons were made between the results obtained for rib samples and the literature values as well as between the results obtained for different ribs from a single individual and for bones from different individuals. (author)

National Institute of Standards and Technology (NIST) cybersecurity risk management framework applied to modern vehicles

Science.gov (United States)

2014-10-01

The primary objective of the work described in this report is to review the National Institute of Science and Technology (NIST) guidelines and foundational publications from an automotive : cybersecurity risk management stand-point. The NIST approach...

Validity and reproducibility of the ErgomoPro power meter compared with the SRM and Powertap power meters.

Science.gov (United States)

Duc, Sebastien; Villerius, Vincent; Bertucci, William; Grappe, Frederic

2007-09-01

The ErgomoPro (EP) is a power meter that measures power output (PO) during outdoor and indoor cycling via 2 optoelectronic sensors located in the bottom bracket axis. The aim of this study was to determine the validity and the reproducibility of the EP compared with the SRM crank set and Powertap hub (PT). The validity of the EP was tested in the laboratory during 8 submaximal incremental tests (PO: 100 to 400 W), eight 30-min submaximal constant-power tests (PO = 180 W), and 8 sprint tests (PO > 750 W) and in the field during 8 training sessions (time: 181 +/- 73 min; PO: approximately 140 to 160 W). The reproducibility was assessed by calculating the coefficient of PO variation (CV) during the submaximal incremental and constant tests. The EP provided a significantly higher PO than the SRM and PT during the submaximal incremental test: The mean PO differences were +6.3% +/- 2.5% and +11.1% +/- 2.1% respectively. The difference was greater during field training sessions (+12.0% +/- 5.7% and +16.5% +/- 5.9%) but lower during sprint tests (+1.6% +/- 2.5% and +3.2% +/- 2.7%). The reproducibility of the EP is lower than those of the SRM and PT (CV = 4.1% +/- 1.8%, 1.9% +/- 0.4%, and 2.1% +/- 0.8%, respectively). The EP power meter appears less valid and reliable than the SRM and PT systems.

Agreement of Power Measures between Garmin Vector and SRM Cycle Power Meters

Science.gov (United States)

Novak, Andrew R.; Dascombe, Benjamin J.

2016-01-01

This study aimed to determine if the Garmin Vector (Schaffhausen, Switzerland) power meter produced acceptable measures when compared with the Schoberer Rad Messetechnik (SRM; Julich, Germany) power meter across a range of high-intensity efforts. Twenty-one well-trained cyclists completed power profiles (seven maximal mean efforts between 5 and…

NIST Photoionization of CO2 (ARPES) Database

Science.gov (United States)

SRD 119 NIST Photoionization of CO2 (ARPES) Database (Web, free access)   CO2 is studied using dispersed synchrotron radiation in the 650 Å to 850 Å spectral region. The vibrationally resolved photoelectron spectra are analyzed to generate relative vibrational transition amplitudes and the angular asymmetry parameters describing the various transitions observed.

Milk and serum standard reference materials for monitoring organic contaminants in human samples.

Science.gov (United States)

Schantz, Michele M; Eppe, Gauthier; Focant, Jean-François; Hamilton, Coreen; Heckert, N Alan; Heltsley, Rebecca M; Hoover, Dale; Keller, Jennifer M; Leigh, Stefan D; Patterson, Donald G; Pintar, Adam L; Sharpless, Katherine E; Sjödin, Andreas; Turner, Wayman E; Vander Pol, Stacy S; Wise, Stephen A

2013-02-01

Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4'-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis.

A Complementary Vision Strategy for Autonomous Robots in Underground Terrains using SRM and Entropy Models

Directory of Open Access Journals (Sweden)

Omowunmi Isafiade

2013-09-01

Full Text Available This work investigates robots' perception in underground terrains (mines and tunnels using statistical region merging (SRM and the entropy models. A probabilistic approach based on the local entropy is employed. The entropy is measured within a fixed window on a stream of mine and tunnel frames to compute features used in the segmentation process, while SRM reconstructs the main structural components of an imagery by a simple but effective statistical analysis. An investigation is conducted on different regions of the mine, such as the shaft, stope and gallery, using publicly available mine frames, with a stream of locally captured mine images. Furthermore, an investigation is also conducted on a stream of dynamic underground tunnel image frames, using the XBOX Kinect 3D sensors. The Kinect sensors produce streams of red, green and blue (RGB and depth images of 640 × 480 resolution at 30 frames per second. Integrating the depth information into drivability gives a strong cue to the analysis, which detects 3D results augmenting drivable and non-drivable regions in 2D. The results of the 2D and 3D experiment with different terrains, mines and tunnels, together with the qualitative and quantitative evaluations, reveal that a good drivable region can be detected in dynamic underground terrains.

77 FR 52692 - NIST Federal Information Processing Standard (FIPS) 140-3 (Second Draft), Security Requirements...

Science.gov (United States)

2012-08-30

...-03] NIST Federal Information Processing Standard (FIPS) 140-3 (Second Draft), Security Requirements....'' Authority: Federal Information Processing Standards (FIPS) are issued by the National Institute of Standards... Standards and Technology (NIST) seeks additional comments on specific sections of Federal Information...

76 FR 58248 - Proposed Information Collection; Comment Request; NIST Three-Year Generic Request for Customer...

Science.gov (United States)

2011-09-20

... Collection; Comment Request; NIST Three-Year Generic Request for Customer Service-Related Data Collections... customers want and expect, as well as their satisfaction with and awareness of existing products, services, and information. In addition, NIST proposes other customer service satisfaction data collections that...

Grid data access on widely distributed worker nodes using Scalla and SRM

Czech Academy of Sciences Publication Activity Database

Jakl, Pavel; Lauret, J.; Hanushevsky, A.; Shoshani, A.; Sim, A.; Gu, J.

2008-01-01

Roč. 119, - (2008), 072019/1-072019/11 ISSN 1742-6588 R&D Projects: GA ČR GA202/07/0079; GA MŠk LC07048 Institutional research plan: CEZ:AV0Z10480505 Keywords : Scalla * SRM * RHIC Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

PChopper: high throughput peptide prediction for MRM/SRM transition design

Directory of Open Access Journals (Sweden)

Huang Jeffrey T-J

2011-08-01

Full Text Available Abstract Background The use of selective reaction monitoring (SRM based LC-MS/MS analysis for the quantification of phosphorylation stoichiometry has been rapidly increasing. At the same time, the number of sites that can be monitored in a single LC-MS/MS experiment is also increasing. The manual processes associated with running these experiments have highlighted the need for computational assistance to quickly design MRM/SRM candidates. Results PChopper has been developed to predict peptides that can be produced via enzymatic protein digest; this includes single enzyme digests, and combinations of enzymes. It also allows digests to be simulated in 'batch' mode and can combine information from these simulated digests to suggest the most appropriate enzyme(s to use. PChopper also allows users to define the characteristic of their target peptides, and can automatically identify phosphorylation sites that may be of interest. Two application end points are available for interacting with the system; the first is a web based graphical tool, and the second is an API endpoint based on HTTP REST. Conclusions Service oriented architecture was used to rapidly develop a system that can consume and expose several services. A graphical tool was built to provide an easy to follow workflow that allows scientists to quickly and easily identify the enzymes required to produce multiple peptides in parallel via enzymatic digests in a high throughput manner.

The reactor and cold neutron research facility at NIST

Energy Technology Data Exchange (ETDEWEB)

Prask, H J; Rowe, J M [Reactor Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD (United States)

1992-07-01

The NIST Reactor (NBSR) is a 20 MW research reactor located at the Gaithersburg, MD site, and has been in operation since 1969. It services 26 thermal neutron facilities which are used for materials science, chemical analysis, nondestructive evaluation, neutron standards work, and irradiations. In 1987 the Department of Commerce and NIST began development of the CNRF - a $30M National Facility for cold neutron research -which will provide fifteen new experimental stations with capabilities currently unavailable in this country. As of May 1992, four of the planned seven guides and a cold port were installed, eight cold neutron experimental stations were operational, and the Call for Proposals for the second cycle of formally-reviewed guest-researcher experiments had been sent out. Some details of the performance of instrumentation are described, along with the proposed design of the new hydrogen cold source which will replace the present D{sub 2}O/H{sub 2}O ice cold source. (author)

The reactor and cold neutron research facility at NIST

International Nuclear Information System (INIS)

Prask, H.J.; Rowe, J.M.

1992-01-01

The NIST Reactor (NBSR) is a 20 MW research reactor located at the Gaithersburg, MD site, and has been in operation since 1969. It services 26 thermal neutron facilities which are used for materials science, chemical analysis, nondestructive evaluation, neutron standards work, and irradiations. In 1987 the Department of Commerce and NIST began development of the CNRF - a $30M National Facility for cold neutron research -which will provide fifteen new experimental stations with capabilities currently unavailable in this country. As of May 1992, four of the planned seven guides and a cold port were installed, eight cold neutron experimental stations were operational, and the Call for Proposals for the second cycle of formally-reviewed guest-researcher experiments had been sent out. Some details of the performance of instrumentation are described, along with the proposed design of the new hydrogen cold source which will replace the present D 2 O/H 2 O ice cold source. (author)

Adaptação transcultural da versão brasileira da escala Social Rhythm Metric-17 (SRM-17 para a população angolana Cross-cultural adaptation of the Brazilian version of the Social Rhythm Metric-17 (SRM-17 for the population of Angola

Directory of Open Access Journals (Sweden)

Regina Lopes Schimitt

2011-01-01

Full Text Available INTRODUÇÃO: O ritmo social é um conceito que integra a relação entre Zeitgebers (sincronizadores sociais e os marcadores de tempo endógenos, e pode ser avaliado com a Escala de Ritmo Social (Social Rhythm Metric-17, SRM-17. O objetivo deste estudo foi realizar a adaptação da versão brasileira da SRM-17 para o português angolano, comparando as duas escalas em populações que utilizam o mesmo idioma mas apresentam diferenças culturais. MÉTODOS: A versão brasileira da SRM-17 foi submetida à avaliação de 10 estudantes universitários angolanos, que analisaram o grau de clareza de cada um dos 15 itens do instrumento usando uma escala visual analógica de 10 cm e propuseram modificações ao texto. Foi realizada revisão dos resultados para a elaboração da versão final, bem como prova de leitura e relatório final. RESULTADOS: A versão final angolana manteve uma equivalência de itens com relação à versão em português brasileiro. A versão avaliada demonstrou um grau satisfatório de clareza e equivalência semântica na maioria dos itens. Porém, alguns itens apresentaram um escore na clareza inferior à média aritmética de compreensão global do instrumento (8,38±1,0. CONCLUSÃO: Apesar de o português ser o idioma oficial nos dois países, há diferenças culturais significativas nas duas populações. Este trabalho apresenta uma versão adaptada à realidade angolana de um instrumento específico para aferir ritmo social. O processo de adaptação transcultural deve efetivar-se com estudos de validação do instrumento final em uma amostra maior da população, onde também poderão ser avaliadas as equivalências operacional, de medida e funcional.INTRODUCTION: Social rhythm is a concept that correlates social Zeitgebers (synchronizers with endogenous markers of time, and can be assessed with the Social Rhythm Metric-17 (SRM-17. The aim of this study was to adapt the Brazilian version of the SRM-17 to Angolan

Hg0 and HgCl2 Reference Gas Standards: NIST Traceability and Comparability (And EPA ALT Methods for Hg and HCl )

Science.gov (United States)

EPA and NIST have collaborated to establish the necessary procedures for establishing the required NIST traceability of commercially-provided Hg0 and HgCl2 reference generators. This presentation will discuss the approach of a joint EPA/NIST study to accurately quantify the tru...

75 FR 18819 - Second DRAFT NIST Interagency Report (NISTIR) 7628, Smart Grid Cyber Security Strategy and...

Science.gov (United States)

2010-04-13

... a cyber attack. 2. It is essential that those parts or equipment of the Smart Grid that optimize the...-0143-01] Second DRAFT NIST Interagency Report (NISTIR) 7628, Smart Grid Cyber Security Strategy and... (NIST) seeks comments on the second draft of NISTIR 7628, Smart Grid Cyber Security Strategy and...

Determination of trace sulfur in biodiesel and diesel standard reference materials by isotope dilution sector field inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Amais, Renata S. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Long, Stephen E. [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States); Nóbrega, Joaquim A. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Christopher, Steven J., E-mail: steven.christopher@nist.gov [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States)

2014-01-02

Graphical abstract: -- Highlights: •Sulfur mass fractions are measured below 10 mg kg{sup −1} in diesel fuel materials. •SF-ICP-MS resolves molecular interferences, including oxygen and sulfur hydrides. •A detection limit of 0.7 mg kg{sup −1} (in the fuel sample) was obtained. -- Abstract: A method is described for quantification of sulfur at low concentrations on the order of mg kg{sup −1} in biodiesel and diesel fuels using isotope dilution and sector field inductively coupled plasma mass spectrometry (ID-SF-ICP-MS). Closed vessel microwave-assisted digestion was employed using a diluted nitric acid and hydrogen peroxide decomposition medium to reduce sample dilution volumes. Medium resolution mode was employed to eliminate isobaric interferences at {sup 32}S and {sup 34}S related to polyatomic phosphorus and oxygen species, and sulfur hydride species. The method outlined yielded respective limits of detection (LOD) and limits of quantification (LOQ) of 0.7 mg kg{sup −1} S and 2.5 mg kg{sup −1} S (in the sample). The LOD was constrained by instrument background counts at {sup 32}S but was sufficient to facilitate value assignment of total S mass fraction in NIST SRM 2723b Sulfur in Diesel Fuel Oil at 9.06 ± 0.13 mg kg{sup −1}. No statistically significant difference at a 95% confidence level was observed between the measured and certified values for certified reference materials NIST SRM 2773 B100 Biodiesel (Animal-Based), CENAM DRM 272b and NIST SRM 2723a Sulfur in Diesel Fuel Oil, validating method accuracy.

Further Investigations of NIST Water Sphere Discrepancies

International Nuclear Information System (INIS)

Broadhead, B.L.

2001-01-01

Measurements have been performed on a family of water spheres at the National Institute of Standards and Technology (NIST) facilities. These measurements are important for criticality safety studies in that, frequently, difficulties have arisen in predicting the reactivity of individually subcritical components assembled in a critical array. It has been postulated that errors in the neutron leakage from individual elements in the array could be responsible for these problems. In these NIST measurements, an accurate determination of the leakage from a fission spectrum, modified by water scattering, is available. Previously, results for 3-, 4-, and 5-in. diam. water-filled spheres, both with and without cadmium covers over the fission chambers, were presented for four fissionable materials: 235 U, 238 U, 237 Np, and 239 Pu. Results were also given for ''dry'' systems, in which the water spheres were drained of water, with the results corresponding to essentially measurements of unmoderated 252 Cf spontaneous-fission neutrons. The calculated-to-experimental (C/E) values ranged from 0.94 to 1.01 for the dry systems and 0.93 to 1.05 for the wet systems, with experimental uncertainties ranging from 1.5 to 1.9%. These results indicated discrepancies that were clearly outside of the experimental uncertainties, and further investigation was suggested. This work updates the previous calculations with a comparison of the predicted C/E values with ENDF/B-V and ENDF/B-VI transport cross sections. Variations in the predicted C/E values that arise from the use of ENDF/B-V, ENDF/B-VI, ENDL92, and LLLDOS for the response fission cross sections are also tabulated. The use of both a 45-group NIST fission spectrum and a continuous-energy fission spectrum for 252 Cf are evaluated. The use of the generalized-linear-least-squares (GLLSM) procedures to investigate the reported discrepancies in the water sphere results for 235 U, 238 U, 239 Pu, and 237 Np is reported herein. These studies

Development of the NAA Laboratory for an Accreditation Obtains

International Nuclear Information System (INIS)

Sri Wardani; Rina M, Th.; Sunarko, M.; Ratnawati, E.

2004-01-01

The evaluation of capability of the neutron activation analysis comparative method and laboratory equipment at P2TRR have been performed by analyzed a reference standard materials prepared by NIST, namely: SRM 1646a and SRM 1648 by a both of comparative and ko- NAA methods. From the analysis results used a comparative method shown that the method and laboratory equipment used at P2TRR obtained in a good precision, accuracy and high sensitivity. In this experiments a few elements could analyzed, namely: V, Ti, Mn, Cl, As, Sm, La, Na, Sc, Cr, Fe, Co, Se, Br, In, Sb, Ba, Cs, Ce, W, U, and Zn. The deviation values results compared with certificate values (NIST) obtained in a range 2 - 12.5% with confidence levels in range 68 - 98%. While, a reference standard material of SRM 1648 analyzed by k 0 -NAA method shown that the method need more research and study continued. From the qualitatively analysis results for short-lived nuclides category analysis by k 0 -NAA could identified a few elements, namely: V, Cu, Na, As and U with standard deviation values in range 1- 11% and limit detection values are 1.6 (U), 6.4 (Cu), 11.2 (V), 73.3 (As) and 199.9 (Na) μg/g for a SRM 1648. For analysis of CRM 8 the results obtained on standard deviation values in range 1 - 13 % and limit detection of 0.71 (Cu), 1.2 (As), 2.4 (V) and 375.9 (Na) μg/g. (author)

In-situ burning: NIST studies

International Nuclear Information System (INIS)

Evans, D.D.

1992-01-01

In-situ burning of spilled oil has distinct advantages over other countermeasures. It offers the potential to convert rapidly large quantities of oil into its primary combustion products, carbon dioxide and water, with a small percentage of other unburned and residue byproducts. Because the oil is converted to gaseous products of combustion by burning, the need for physical collection, storage, and transport of recovered fluids is reduced to the few percent of the original spill volume that remains as residue after burning. Burning oil spills produces a visible smoke plume containing smoke particulate and other products of combustion which may persist for many kilometers from the burn. This fact gives rise to public health concerns, related to the chemical content of the smoke plume and the downwind deposition of particulate, which need to be answered. In 1985, a joint Minerals Management Service (MMS) and Environment Canada (EC) in-situ burning research program was begun at the National Institute of Standards and Technology (NIST). This research program was designed to study the burning of large crude oil spills on water and how this burning would affect air quality by quantifying the products of combustion and developing methods to predict the downwind smoke particulate deposition. To understand the important features of in-situ burning, it is necessary to perform both laboratory and mesoscale experiments. Finally, actual burns of spilled oil at sea will be necessary to evaluate the method at the anticipated scale of actual response operations. In this research program there is a continuing interaction between findings from measurements on small fire experiments performed in the controlled laboratory environments of NIST and the Fire Research Institute (FRI) in Japan, and large fire experiments at facilities like the USCG Fire Safety and Test Detachment in Mobile, Alabama where outdoor liquid fuel burns in large pans are possible

The NIST Step Class Library (Step Into the Future)

Science.gov (United States)

1990-09-01

Figure 6. Excerpt from a STEP exclange file based on the Geometry model 1be NIST STEP Class Libary Page 13 An issue of concern in this...Scheifler, R., Gettys, J., and Newman, P., X Window System: C Library and Protocol Reference. Digital Press, Bedford, Mass, 1988. [Schenck90] Schenck, D

Conversion Preliminary Safety Analysis Report for the NIST Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Diamond, D. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Baek, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hanson, A. L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cheng, L-Y [Brookhaven National Lab. (BNL), Upton, NY (United States); Brown, N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Cuadra, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-01-30

The NIST Center for Neutron Research (NCNR) is a reactor-laboratory complex providing the National Institute of Standards and Technology (NIST) and the nation with a world-class facility for the performance of neutron-based research. The heart of this facility is the NIST research reactor (aka NBSR); a heavy water moderated and cooled reactor operating at 20 MW. It is fueled with high-enriched uranium (HEU) fuel elements. A Global Threat Reduction Initiative (GTRI) program is underway to convert the reactor to low-enriched uranium (LEU) fuel. This program includes the qualification of the proposed fuel, uranium and molybdenum alloy foil clad in an aluminum alloy, and the development of the fabrication techniques. This report is a preliminary version of the Safety Analysis Report (SAR) that would be submitted to the U.S. Nuclear Regulatory Commission (NRC) for approval prior to conversion. The report follows the recommended format and content from the NRC codified in NUREG-1537, “Guidelines for Preparing and Reviewing Applications for the Licensing of Non-power Reactors,” Chapter 18, “Highly Enriched to Low-Enriched Uranium Conversions.” The emphasis in any conversion SAR is to explain the differences between the LEU and HEU cores and to show the acceptability of the new design; there is no need to repeat information regarding the current reactor that will not change upon conversion. Hence, as seen in the report, the bulk of the SAR is devoted to Chapter 4, Reactor Description, and Chapter 13, Safety Analysis.

76 FR 66040 - NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0 (Draft...

Science.gov (United States)

2011-10-25

...-01] NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0 (Draft... draft version of the NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0... Roadmap for Smart Grid Interoperability Standards, Release 2.0 (Release 2.0) (Draft) for public review and...

Development of a highly precise ID-ICP-SFMS method for analysis of low concentrations of lead in rice flour reference materials.

Science.gov (United States)

Zhu, Yanbei; Inagaki, Kazumi; Yarita, Takashi; Chiba, Koichi

2008-07-01

Microwave digestion and isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-SFMS) has been applied to the determination of Pb in rice flour. In order to achieve highly precise determination of low concentrations of Pb, the digestion blank for Pb was reduced to 0.21 ng g(-1) after optimization of the digestion conditions, in which 20 mL analysis solution was obtained after digestion of 0.5 g rice flour. The observed value of Pb in a non-fat milk powder certified reference material (CRM), NIST SRM 1549, was 16.8 +/- 0.8 ng g(-1) (mean +/- expanded uncertainty, k = 2; n = 5), which agreed with the certified value of 19 +/- 3 ng g(-1) and indicated the effectiveness of the method. Analytical results for Pb in three brown rice flour CRMs, NIST SRM 1568a, NIES CRM 10-a, and NIES CRM 10-b, were 7.32 +/- 0.24 ng g(-1) (n = 5), 1010 +/- 10 ng g(-1) (n = 5), and 1250 +/- 20 ng g(-1) (n = 5), respectively. The concentration of Pb in a candidate white rice flour reference material (RM) sample prepared by the National Metrology Institute of Japan (NMIJ) was observed to be 4.36 +/- 0.28 ng g(-1) (n = 10 bottles).

Quantum Information Experiments with Trapped Ions at NIST

Science.gov (United States)

Wilson, Andrew

2015-03-01

We present an overview of recent trapped-ion quantum information experiments at NIST. Advancing beyond few-qubit ``proof-of-principle'' experiments to the many-qubit systems needed for practical quantum simulation and information processing, without compromising on the performance demonstrated with small systems, remains a major challenge. One approach to scalable hardware development is surface-electrode traps. Micro-fabricated planar traps can have a number of useful features, including flexible electrode geometries, integrated microwave delivery, and spatio-temporal tuning of potentials for ion transport and spin-spin interactions. In this talk we report on a number of on-going investigations with surface traps. Experiments feature a multi-zone trap with closely spaced ions in a triangular arrangement (a first step towards 2D arrays of ions with tunable spin-spin interactions), a scheme for smooth transport through a junction in a 2D structure based on switchable RF potentials, and a micro-fabricated photo-detector integrated into a trap. We also give a progress report on our latest efforts to improve the fidelity of both optical and microwave 2-qubit gates. This work was supported by IARPA, ONR and the NIST Quantum Information Program. The 3-ion and switchable-RF-junction traps were developed in collaboration with Sandia National Laboratory.

USCEA/NIST measurement assurance programs for the radiopharmaceutical and nuclear power industries

International Nuclear Information System (INIS)

Golas, D.B.

1993-01-01

In cooperation with the U.S. Council for Energy Awareness (USCEA), the National Institute of Standards and Technology (NIST) supervises and administers two measurement assurance programs for radioactivity measurement traceability. One, in existence since the mid 1970s, provides traceability to suppliers of radiochemicals and radiopharmaceuticals, dose calibrators, and nuclear pharmacy services. The second program, begun in 1987, provides traceability to the nuclear power industry for utilities, source suppliers, and service laboratories. Each program is described, and the results of measurements of samples of known, but undisclosed activity, prepared at NIST and measured by the participants are presented

USCEA/NIST measurement assurance programs for the radiopharmaceutical and nuclear power industries

Energy Technology Data Exchange (ETDEWEB)

Golas, D.B. [Council for Energy Awareness, Washington, DC (United States)

1993-12-31

In cooperation with the U.S. Council for Energy Awareness (USCEA), the National Institute of Standards and Technology (NIST) supervises and administers two measurement assurance programs for radioactivity measurement traceability. One, in existence since the mid 1970s, provides traceability to suppliers of radiochemicals and radiopharmaceuticals, dose calibrators, and nuclear pharmacy services. The second program, begun in 1987, provides traceability to the nuclear power industry for utilities, source suppliers, and service laboratories. Each program is described, and the results of measurements of samples of known, but undisclosed activity, prepared at NIST and measured by the participants are presented.

Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

Science.gov (United States)

Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

1989-01-01

A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru

A High Torque Density Axial Flux SRM with Modular Stator

Directory of Open Access Journals (Sweden)

Y Ebrahimi

2015-12-01

Full Text Available A novel structure of switched reluctance motors (SRMs is proposed. The proposed structure uses the benefits of the axial flux path, short flux path, segmental rotor, and flux reversal free stator motors all together to improve the torque density of the SRMs. The main geometrical, electrical and physical specifications are presented. In addition, some features of the proposed structure are compared with those of a state-of-the-art radial flux SRM, considered as a reference motor. Then, the proposed structure is modified by employing a higher number of rotor segments than the stator modules and at the same time, reshaped stator modules tips. Achieved results reveal that, compared with the reference motor, the proposed and the modified proposed motors deliver about the same torque with 36.5% and 46.7% lower active material mass, respectively. The efficiency and torque production capability for the extended current densities are also retained. These make the proposed structures a potentially proper candidate for the electric vehicles (EVs and hybrid electric vehicles (HEVs as an in-wheel motor.

Fit for purpose validated method for the determination of the strontium isotopic signature in mineral water samples by multi-collector inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Brach-Papa, Christophe; Van Bocxstaele, Marleen; Ponzevera, Emmanuel [European Commission - Joint Research Centre - Institute for Reference Materials and Measurements, Retieseweg 111 - 2440 Geel (Belgium); Quetel, Christophe R. [European Commission - Joint Research Centre - Institute for Reference Materials and Measurements, Retieseweg 111 - 2440 Geel (Belgium)], E-mail: christophe.quetel@ec.europa.eu

2009-03-15

A robust method allowing the routine determination of n({sup 87}Sr)/n({sup 86}Sr) with at least five significant decimal digits for large sets of mineral water samples is described. It is based on 2 consecutive chromatographic separations of Sr associated to multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) measurements. Separations are performed using commercial pre-packed columns filled with 'Sr resin' to overcome isobaric interferences affecting the determination of strontium isotope ratios. The careful method validation scheme applied is described. It included investigations on all parameters influencing both chromatographic separations and MC-ICPMS measurements, and also the test on a synthetic sample made of an aliquot of the NIST SRM 987 certified reference material dispersed in a saline matrix to mimic complex samples. Correction for mass discrimination was done internally using the n({sup 88}Sr)/n({sup 86}Sr) ratio. For comparing mineral waters originating from different geological backgrounds or identifying counterfeits, calculations involved the well known consensus value (1/0.1194) {+-} 0 as reference. The typical uncertainty budget estimated for these results was 40 'ppm' relative (k = 2). It increased to 150 'ppm' (k = 2) for the establishment of stand alone results, taking into account a relative difference of about 126 'ppm' systematically observed between measured and certified values of the NIST SRM 987. In case there was suspicion of a deviation of the n({sup 88}Sr)/n({sup 86}Sr) ratio (worst case scenario) our proposal was to use the NIST SRM 987 value 8.37861 {+-} 0.00325 (k = 2) as reference, and assign a typical relative uncertainty budget of 300 'ppm' (k = 2). This method is thus fit for purpose and was applied to eleven French samples.

Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

Energy Technology Data Exchange (ETDEWEB)

Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

2013-07-15

The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)

Minerals and trace elements determination in diets by neutron activation analysis; Determinacao de elementos minerais e tracos em dietas pela tecnica de ativacao neutronica

Energy Technology Data Exchange (ETDEWEB)

Eiras, Maria Izabel O.; Favaro, Debora I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica; Ribeiro, Marisilda; Cozzolino, Silvia M.F. [Sao Paulo Univ., SP (Brazil). Dept. de Alimentos e Nutricao Experimental. Lab. de Minerais

2002-07-01

In the present study 12 diets, each one consisting of a pool of seven day diets, composed by four meals: breakfast, lunch, dinner and snack, adequate in energy and macro nutrients according to the RDA (Recommended Daily Allowance) recommendations, were elaborated and offered to a group of 12 men (19-42 years). The diets were collected by duplicate portion technique and dried by two different processes: freeze drying and 60 deg C ventilated oven drying. In the total, 24 diets were analyzed. The content of some minerals and trace elements (Ca, Fe, Mg, Mn, Na, Se and Zn) were determined by Instrumental Neutron Activation Analysis. The validation of methodology was made by analysis of the reference materials Typical Diet (NIST SRM 1548{sup a}), Orchard Leaves (NIST SRM 1541) and Peach Leaves (NIST SRM 1547). The results observed by two different drying processes used were statistically compared by test T of Student. It was possible to conclude that the concentration means can be considered as statistically equal, within a significance level of 0.05. The daily intake values calculated from the concentration results were: 712 ({+-} 59) mg Ca/day; 10.7 ({+-} 0.8) mg Fe/ day; 3387 ({+-} 16) mg K/ day; 275 ({+-} 6) mg Mg/ day; 3.0 ({+-} 0.5) mg Mn/ day; 3656 ({+-} 699) mg Na/ day; 42 ({+-} 6) {mu}g Se/ day e 11.6 ({+-} 2.4) mg Zn/ day. The calculated intake was compared to the new daily recommended values set by RDA (National Research Council-USA) for the range age of individuals studied. It was possible to conclude that the diets were adequate in Fe and Zn and inadequate for the other elements. Concerning the minerals Na and K we verified high daily intake levels and this was already observed in other Brazilian regional diets. (author)

Minerals and trace elements determination in diets by neutron activation analysis

International Nuclear Information System (INIS)

Eiras, Maria Izabel O.; Favaro, Debora I.T.; Ribeiro, Marisilda; Cozzolino, Silvia M.F.

2002-01-01

In the present study 12 diets, each one consisting of a pool of seven day diets, composed by four meals: breakfast, lunch, dinner and snack, adequate in energy and macro nutrients according to the RDA (Recommended Daily Allowance) recommendations, were elaborated and offered to a group of 12 men (19-42 years). The diets were collected by duplicate portion technique and dried by two different processes: freeze drying and 60 deg C ventilated oven drying. In the total, 24 diets were analyzed. The content of some minerals and trace elements (Ca, Fe, Mg, Mn, Na, Se and Zn) were determined by Instrumental Neutron Activation Analysis. The validation of methodology was made by analysis of the reference materials Typical Diet (NIST SRM 1548 a ), Orchard Leaves (NIST SRM 1541) and Peach Leaves (NIST SRM 1547). The results observed by two different drying processes used were statistically compared by test T of Student. It was possible to conclude that the concentration means can be considered as statistically equal, within a significance level of 0.05. The daily intake values calculated from the concentration results were: 712 (± 59) mg Ca/day; 10.7 (± 0.8) mg Fe/ day; 3387 (± 16) mg K/ day; 275 (± 6) mg Mg/ day; 3.0 (± 0.5) mg Mn/ day; 3656 (± 699) mg Na/ day; 42 (± 6) μg Se/ day e 11.6 (± 2.4) mg Zn/ day. The calculated intake was compared to the new daily recommended values set by RDA (National Research Council-USA) for the range age of individuals studied. It was possible to conclude that the diets were adequate in Fe and Zn and inadequate for the other elements. Concerning the minerals Na and K we verified high daily intake levels and this was already observed in other Brazilian regional diets. (author)

Covariance methodology applied to 35S disintegration rate measurements by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Koskinas, M.F.; Nascimento, T.S.; Yamazaki, I.M.; Dias, M.S.

2014-01-01

The Nuclear Metrology Laboratory (LMN) at IPEN is carrying out measurements in a LSC (Liquid Scintillation Counting system), applying the CIEMAT/NIST method. In this context 35 S is an important radionuclide for medical applications and it is difficult to be standardized by other primary methods due to low beta ray energy. The CIEMAT/NIST is a standard technique used by most metrology laboratories in order to improve accuracy and speed up beta emitter standardization. The focus of the present work was to apply the covariance methodology for determining the overall uncertainty in the 35 S disintegration rate. All partial uncertainties involved in the measurements were considered, taking into account all possible correlations between each pair of them. - Highlights: ► 35 S disintegration rate measured in Liquid Scintillator system using CIEMAT/NIST method. ► Covariance methodology applied to the overall uncertainty in the 35 S disintegration rate. ► Monte Carlo simulation was applied to determine 35 S activity in the 4πβ(PC)-γ coincidence system

Speciation of Mn(II), Mn(VII) and total manganese in water and food samples by coprecipitation-atomic absorption spectrometry combination

International Nuclear Information System (INIS)

Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2010-01-01

A speciation procedure based on the coprecipitation of manganese(II) with zirconium(IV) hydroxide has been developed for the investigation of levels of manganese species. The determination of manganese levels was performed by flame atomic absorption spectrometry (FAAS). Total manganese was determined after the reduction of Mn(VII) to Mn(II) by ascorbic acid. The analytical parameters including pH, amount of zirconium(IV), sample volume, etc., were investigated for the quantitative recoveries of manganese(II). The effects of matrix ions were also examined. The recoveries for manganese(II) were in the range of 95-98%. Preconcentration factor was calculated as 50. The detection limit for the analyte ions based on 3 sigma (n = 21) was 0.75 μg L -1 for Mn(II). The relative standard deviation was found to be lower than 7%. The validation of the presented procedure was performed by analysis of certified reference material having different matrices, NIST SRM 1515 (Apple Leaves) and NIST SRM 1568a (Rice Flour). The procedure was successfully applied to natural waters and food samples.

Experimental efforts at NIST towards one-electron ions in circular Rydberg states

International Nuclear Information System (INIS)

Tan, Joseph N; Guise, Nicholas D; Brewer, Samuel M

2011-01-01

Experimental effort is underway at NIST to enable tests of theory with one-electron ions synthesized in circular Rydberg states from captured bare nuclei. Problematic effects that limit the accuracy of predicted energy levels for low-lying states are vanishingly small for high-angular-momentum (high-L) states; in particular, the nuclear size correction for high-L states is completely negligible for any foreseeable improvement of measurement precision. As an initial step towards realizing such states, highly charged ions are extracted from the NIST electron beam ion trap (EBIT) and steered through the electrodes of a Penning trap. The goal is to capture bare nuclei in the Penning trap for experiments to make one-electron atoms in circular Rydberg states with dipole (E1) transitions in the optical domain accessible to a frequency comb.

Characterization of LANDSAT Panels Using the NIST BRDF Scale from 1100 nm to 2500 nm

Science.gov (United States)

Markham, Brian; Tsai, Benjamin K.; Allen, David W.; Cooksey, Catherine; Yoon, Howard; Hanssen, Leonard; Zeng, Jinan; Fulton, Linda; Biggar, Stuart; Markham, Brian

2010-01-01

Many earth observing sensors depend on white diffuse reflectance standards to derive scales of radiance traceable to the St Despite the large number of Earth observing sensors that operate in the reflective solar region of the spectrum, there has been no direct method to provide NIST traceable BRDF measurements out to 2500 rim. Recent developments in detector technology have allowed the NIST reflectance measurement facility to expand the operating range to cover the 250 nm to 2500 nm range. The facility has been modified with and additional detector using a cooled extended range indium gallium arsenide (Extended InGaAs) detector. Measurements were made for two PTFE white diffuse reflectance standards over the 1100 nm to 2500 nm region at a 0' incident and 45' observation angle. These two panels will be used to support the OLI calibration activities. An independent means of verification was established using a NIST radiance transfer facility based on spectral irradiance, radiance standards and a diffuse reflectance plaque. An analysis on the results and associated uncertainties will be discussed.

Corrections of the NIST Statistical Test Suite for Randomness

OpenAIRE

Kim, Song-Ju; Umeno, Ken; Hasegawa, Akio

2004-01-01

It is well known that the NIST statistical test suite was used for the evaluation of AES candidate algorithms. We have found that the test setting of Discrete Fourier Transform test and Lempel-Ziv test of this test suite are wrong. We give four corrections of mistakes in the test settings. This suggests that re-evaluation of the test results should be needed.

Supervised and Unsupervised Speaker Adaptation in the NIST 2005 Speaker Recognition Evaluation

National Research Council Canada - National Science Library

Hansen, Eric G; Slyh, Raymond E; Anderson, Timothy R

2006-01-01

Starting in 2004, the annual NIST Speaker Recognition Evaluation (SRE) has added an optional unsupervised speaker adaptation track where test files are processed sequentially and one may update the target model...

The TNO speaker diarization system for NIST RT05s meeting data

NARCIS (Netherlands)

Leeuwen, D.A. van

2006-01-01

The TNO speaker speaker diarization system is based on a standard BIC segmentation and clustering algorithm. Since for the NIST Rich Transcription speaker dizarization evaluation measure correct speech detection appears to be essential, we have developed a speech activity detector (SAD) as well.

Cold neutron prompt gamma activation analysis at NIST; A progress report

Energy Technology Data Exchange (ETDEWEB)

Paul, R L; Lindstrom, R M [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Div. of Inorganic Analytical Research; Vincent, D H [Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

1994-05-01

An instrument for prompt gamma-ray activation analysis is now in operation at the NIST Cold Neutron Research Facility (CNRF). The cold neutron beam is relatively free of contamination by fast neutrons and reactor gamma rays, and the neutron fluence rate is 1.5 x 10 [sup 8] cm [sup -2] x s [sup -1] (thermal equivalent). As a result of a compact target-detector geometry the sensitivity is better by a factor of as much as seven than that obtained with an existing thermal instrument, and hydrogen background is a factor of 50 lower. This instrument was applied to multielement analysis of the Allende meteorite and other materials. (author) 14 refs.; 2 figs.; 1 tab.

Eulerian–Lagrangian RANS Model Simulations of the NIST Turbulent Methanol Spray Flame

NARCIS (Netherlands)

Zhu, Shanglong; Roekaerts, Dirk; Pozarlik, Artur Krzysztof; van der Meer, Theodorus H.

2015-01-01

A methanol spray flame in a combustion chamber of the NIST was simulated using an Eulerian–Lagrangian RANS model. Experimental data and previous numerical investigations by other researchers on this flame were analyzed to develop methods for more comprehensive model validation. The inlet boundary

In silico design of targeted SRM-based experiments

Directory of Open Access Journals (Sweden)

Nahnsen Sven

2012-11-01

Full Text Available Abstract Selected reaction monitoring (SRM-based proteomics approaches enable highly sensitive and reproducible assays for profiling of thousands of peptides in one experiment. The development of such assays involves the determination of retention time, detectability and fragmentation properties of peptides, followed by an optimal selection of transitions. If those properties have to be identified experimentally, the assay development becomes a time-consuming task. We introduce a computational framework for the optimal selection of transitions for a given set of proteins based on their sequence information alone or in conjunction with already existing transition databases. The presented method enables the rapid and fully automated initial development of assays for targeted proteomics. We introduce the relevant methods, report and discuss a step-wise and generic protocol and we also show that we can reach an ad hoc coverage of 80 % of the targeted proteins. The presented algorithmic procedure is implemented in the open-source software package OpenMS/TOPP.

DELAMINATION AND XRF ANALYSIS OF NIST LEAD IN PAINT FILM STANDARDS

Science.gov (United States)

The objectives of this protocol were to remove the laminate coating from lead paint film standards acquired from NIST by means of surface heating. The average XRF value did not change after removal of the polymer coating suggesting that this protocol is satisfactory for renderin...

The AMI speaker diarization system for NIST RT06s meeting data

NARCIS (Netherlands)

Leeuwen, D.A. van; Huijbregts, Marijn

2006-01-01

We describe the systems submitted to the NIST RT06s evaluation for the Speech Activity Detection (SAD) and Speaker Diarization (SPKR) tasks. For speech activity detection, a new analysis methodology is presented that generalizes the Detection Erorr Tradeoff analysis commonly used in speaker

The AMI speaker diarization system for NIST RT06s meeting data

NARCIS (Netherlands)

van Leeuwen, David A.; Huijbregts, M.A.H.

2007-01-01

We describe the systems submitted to the NIST RT06s evaluation for the Speech Activity Detection (SAD) and Speaker Diarization (SPKR) tasks. For speech activity detection, a new analysis methodology is presented that generalizes the Detection Erorr Tradeoff analysis commonly used in speaker detection

Update of NIST half-life results corrected for ionization chamber source-holder instability

International Nuclear Information System (INIS)

Unterweger, M.P.; Fitzgerald, R.

2014-01-01

As reported at the ICRM 2011, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) was not stable. This has affected a large number of half-life measurement results previously reported and used in compilations of nuclear data. Corrections have been made on all of the half-life data based on the assumption that the changes to the ionization chamber response were gradual. The corrections are energy dependent and therefore radionuclide specific. This presentation will review our results and present the recommended changes in half-life values and/or uncertainties. - Highlights: • The NIST half-life data is corrected for sample positioning variations and refitted. • These results are reported and increased errors in the reported values are given. • Longer lived radionuclides are discussed

The liquid hydrogen moderator at the NIST research reactor

International Nuclear Information System (INIS)

Williams, Robert E.; Rowe, J. Michael; Kopetka, Paul

1997-09-01

In 1995, the NIST research reactor was shut down for a number of modifications, including the replacement of the D 2 O cold neutron source with a liquid hydrogen moderator. When the liquid hydrogen source began operating, the flux of cold neutrons increased by a factor of six over the D 2 O source. The design and operation of the hydrogen source are described, and measurements of its performance are compared with the Monte Carlo simulations used in the design. (auth)

Imaging of elements in leaves of tobacco by solid sampling–electrothermal vaporization–inductively coupled plasma-optical emission spectrometry

Energy Technology Data Exchange (ETDEWEB)

Masson, Pierre, E-mail: masson@bordeaux.inra.fr

2014-12-01

Plants take up and store elements according to the environment in which they are growing. Because plants are at the base of the food chain, the determination of essential elements or toxic elements in plant materials is of importance. However, it is assumed that the element content determined on selected tissues may provide more specific information than that derived from the whole plant analysis. In this work, we assessed the feasibility of solid sampling–electrothermal vaporization–inductively coupled plasma-optical emission spectrometry analyses for quantitative imaging of Cd and Mg in plant leaves. Leaves of tobacco (Nicotiana tabacum) were selected to be used as samples. To produce a two dimensional image, sections cut from leaf samples were analyzed. Cellulose doped with multi-element solution standards was used as calibration samples. Two certified reference materials (NIST SRM 1547 Peach Leaves and NIST SRM 1573a Tomato leaves) were used to verify the accuracy of measurements with good agreement between the measured concentrations and the certified values. Quantitative imaging revealed the inhomogeneous distribution of the selected elements. Excess of Cd and Mg tended to be focused on peripheral regions and the tip of the leaf.

Effects of confinement on rock mass modulus: A synthetic rock mass modelling (SRM study

Directory of Open Access Journals (Sweden)

I. Vazaios

2018-06-01

Full Text Available The main objective of this paper is to examine the influence of the applied confining stress on the rock mass modulus of moderately jointed rocks (well interlocked undisturbed rock mass with blocks formed by three or less intersecting joints. A synthetic rock mass modelling (SRM approach is employed to determine the mechanical properties of the rock mass. In this approach, the intact body of rock is represented by the discrete element method (DEM-Voronoi grains with the ability of simulating the initiation and propagation of microcracks within the intact part of the model. The geometry of the pre-existing joints is generated by employing discrete fracture network (DFN modelling based on field joint data collected from the Brockville Tunnel using LiDAR scanning. The geometrical characteristics of the simulated joints at a representative sample size are first validated against the field data, and then used to measure the rock quality designation (RQD, joint spacing, areal fracture intensity (P21, and block volumes. These geometrical quantities are used to quantitatively determine a representative range of the geological strength index (GSI. The results show that estimating the GSI using the RQD tends to make a closer estimate of the degree of blockiness that leads to GSI values corresponding to those obtained from direct visual observations of the rock mass conditions in the field. The use of joint spacing and block volume in order to quantify the GSI value range for the studied rock mass suggests a lower range compared to that evaluated in situ. Based on numerical modelling results and laboratory data of rock testing reported in the literature, a semi-empirical equation is proposed that relates the rock mass modulus to confinement as a function of the areal fracture intensity and joint stiffness. Keywords: Synthetic rock mass modelling (SRM, Discrete fracture network (DFN, Rock mass modulus, Geological strength index (GSI, Confinement

Primary standardization of {sup 152}Eu by 4πβ(LS) - γ (NaI) coincidence counting and CIEMAT-NIST method

Energy Technology Data Exchange (ETDEWEB)

Ruzzarin, A., E-mail: aruzzarin@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (LIN/PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear; Cruz, P.A.L. da; Ferreira Filho, A.L.; Iwahara, A. [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiações Ionizantes

2017-07-01

The 4πβ-γ coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of {sup 152}Eu. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4πβ-γ coincidence counting, the solution was standardized using a coincidence method with 'beta-efficiency extrapolation'. A simple 4πβ-γ coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180° each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 ± 0.722 and 157.403 ± 0.113 kBq/g, respectively, for CIEMAT/NIST and 4πβ-γ coincidence counting measurement methods. (author)

Analysis of human plasma metabolites across different liquid chromatography/mass spectrometry platforms: Cross-platform transferable chemical signatures.

Science.gov (United States)

Telu, Kelly H; Yan, Xinjian; Wallace, William E; Stein, Stephen E; Simón-Manso, Yamil

2016-03-15

The metabolite profiling of a NIST plasma Standard Reference Material (SRM 1950) on different liquid chromatography/mass spectrometry (LC/MS) platforms showed significant differences. Although these findings suggest caution when interpreting metabolomics results, the degree of overlap of both profiles allowed us to use tandem mass spectral libraries of recurrent spectra to evaluate to what extent these results are transferable across platforms and to develop cross-platform chemical signatures. Non-targeted global metabolite profiles of SRM 1950 were obtained on different LC/MS platforms using reversed-phase chromatography and different chromatographic scales (conventional HPLC, UHPLC and nanoLC). The data processing and the metabolite differential analysis were carried out using publically available (XCMS), proprietary (Mass Profiler Professional) and in-house software (NIST pipeline). Repeatability and intermediate precision showed that the non-targeted SRM 1950 profiling was highly reproducible when working on the same platform (relative standard deviation (RSD) HPLC, UHPLC and nanoLC) on the same platform. A substantial degree of overlap (common molecular features) was also found. A procedure to generate consistent chemical signatures using tandem mass spectral libraries of recurrent spectra is proposed. Different platforms rendered significantly different metabolite profiles, but the results were highly reproducible when working within one platform. Tandem mass spectral libraries of recurrent spectra are proposed to evaluate the degree of transferability of chemical signatures generated on different platforms. Chemical signatures based on our procedure are most likely cross-platform transferable. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

Speaker diarization system on the 2007 NIST rich transcription meeting recognition evaluation

Science.gov (United States)

Sun, Hanwu; Nwe, Tin Lay; Koh, Eugene Chin Wei; Bin, Ma; Li, Haizhou

2007-09-01

This paper presents a speaker diarization system developed at the Institute for Infocomm Research (I2R) for NIST Rich Transcription 2007 (RT-07) evaluation task. We describe in details our primary approaches for the speaker diarization on the Multiple Distant Microphones (MDM) conditions in conference room scenario. Our proposed system consists of six modules: 1). Least-mean squared (NLMS) adaptive filter for the speaker direction estimate via Time Difference of Arrival (TDOA), 2). An initial speaker clustering via two-stage TDOA histogram distribution quantization approach, 3). Multiple microphone speaker data alignment via GCC-PHAT Time Delay Estimate (TDE) among all the distant microphone channel signals, 4). A speaker clustering algorithm based on GMM modeling approach, 5). Non-speech removal via speech/non-speech verification mechanism and, 6). Silence removal via "Double-Layer Windowing"(DLW) method. We achieves error rate of 31.02% on the 2006 Spring (RT-06s) MDM evaluation task and a competitive overall error rate of 15.32% for the NIST Rich Transcription 2007 (RT-07) MDM evaluation task.

Grid Data Access on Widely Distributed Worker Nodes Using Scalla and SRM

International Nuclear Information System (INIS)

Jakl, Pavel; Lauret, Jerome; Hanushevsky, Andrew; Shoshani, Arie; Sim, Alex; Gu, Junmin

2011-01-01

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations.

Grid data access on widely distributed worker nodes using scalla and SRM

International Nuclear Information System (INIS)

Jakl, P; Lauret, J; Hanushevsky, A; Shoshani, A; Sim, A; Gu, J

2008-01-01

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations

Grid Data Access on Widely Distributed Worker Nodes Using Scalla and SRM

Energy Technology Data Exchange (ETDEWEB)

Jakl, Pavel; /Prague, Inst. Phys.; Lauret, Jerome; /Brookhaven; Hanushevsky, Andrew; /SLAC; Shoshani, Arie; /LBL, Berkeley; Sim, Alex; /LBL, Berkeley; Gu, Junmin; /LBL, Berkeley

2011-11-10

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations.

The Validation of AAN Method Used by Rock Sample SRM 2780

International Nuclear Information System (INIS)

Rina Mulyaningsih, Th.

2004-01-01

AAN methods is a non standard testing method. The testing laboratory must be validate its using method to ensure and confirm that it is suitable with application. The analysis of SRM 2780 Hard rock mine waste with 9 replicates has been done to test the accuracy of AAN methods. The result showed that the elements As, Ba, Mn, V, Zn and Na have good accuration were evaluated against the acceptance criteria for accuracy with confidence level 95 %. The elements As, Co, Sc, Cr, Ba, Sb, Cs, Mn, V, Au, Zn and Na have low relative bias between the analyst's value and the target value. The continued testing must be done to test the accuracy of another certificated elements. (author)

Development of an SRM method for absolute quantitation of MYDGF/C19orf10 protein.

Science.gov (United States)

Dwivedi, Ravi C; Krokhin, Oleg V; El-Gabalawy, Hani S; Wilkins, John A

2016-06-01

To develop a MS-based selected reaction monitoring (SRM) assay for quantitation of myeloid-derived growth factor (MYDGF) formerly chromosome 19 open reading frame (C19orf10). Candidate reporter peptides were identified in digests of recombinant MYDGF. Isotopically labeled forms of these reporter peptides were employed as internal standards for assay development. Two reference peptides were selected SYLYFQTFFK and GAEIEYAMAYSK with respective LOQ of 42 and 380 attomole per injection. Application of the assay to human serum and synovial fluid determined that the assay sensitivity was reduced and quantitation was not achievable. However, the partial depletion of albumin and immunoglobulin from synovial fluids provided estimates of 300-650 femtomoles per injection (0.7-1.6 nanomolar (nM) fluid concentrations) in three of the six samples analyzed. A validated sensitive assay for the quantitation of MYDGF in biological fluids was developed. However, the endogenous levels of MYDGF in such fluids are at or below the current levels of quantitation. The levels of MYDGF are lower than those previously reported using an ELISA. The current results suggest that additional steps may be required to remove high abundance proteins or to enrich MYDGF for SRM-based quantitation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Test of sup 3 He-based neutron polarizers at NIST

CERN Document Server

Jones, G L; Thompson, A K; Chowdhuri, Z; Dewey, M S; Snow, W M; Wietfeldt, F E

2000-01-01

Neutron spin filters based on polarized sup 3 He are useful over a wide neutron energy range and have a large angular acceptance among other advantages. Two optical pumping methods, spin-exchange and metastability-exchange, can produce the volume of highly polarized sup 3 He gas required for such neutron spin filters. We report a test of polarizers based on each of these two methods on a new cold, monochromatic neutron beam line at the NIST Center for Neutron Research.

NIST--Los Alamos racetrack microtron status

International Nuclear Information System (INIS)

Wilson, M.A.; Ayres, R.L.; Cutler, R.I.; Debenham, P.H.; Lindstrom, E.R.; Mohr, D.L.; Penner, S.; Rose, J.E.; Young, L.M.

1988-01-01

The NIST-Los Alamos Racetrack Microtron (RTM) is designed to deliver a low-emittance electron beam of up to 0.5 mA cw over an energy range of 17 MeV to 185 MeV. Fed by a 5 MeV injector, the RTM contains two 180 degree end magnets that recirculate the beam up to 15 times through a 12 MeV RF linac. The linac, which operates in a standing-wave mode at 2380 MHz, has been tested to nearly full RF power. At present, the injector has undergone beam tests, and the beam transport system is complete through the 12 MeV linac. A temporary beam line has been installed at the exit of one end magnet to measure the beam energy, energy spread, and emittance after one pass through the accelerator. Preliminary results indicate that the accelerated beam energy spread and emittance are within design goals. 4 refs., 7 figs

Assessing Customer Satisfaction at the NIST Research Library: Essential Tool for Future Planning

Science.gov (United States)

Liu, Rosa; Allmang, Nancy

2008-01-01

This article describes a campus-wide customer satisfaction survey undertaken by the National Institute of Standards and Technology (NIST) Research Library in 2007. The methodology, survey instrument, data analysis, results, and actions taken in response to the survey are described. The outcome and recommendations will guide the library both…

The (TNO) Speaker Diarization System for NIST Rich Transcription Evaluation 2005 for meeting data

NARCIS (Netherlands)

Leeuwen, D.A. van

2005-01-01

Abstract. The TNO speaker speaker diarization system is based on a standard BIC segmentation and clustering algorithm. Since for the NIST Rich Transcription speaker dizarization evaluation measure correct speech detection appears to be essential, we have developed a speech activity detector (SAD) as

Concurso NIST. Análisis del concurso (2007-2012)

OpenAIRE

Martín Sierra, Marían

2014-01-01

El objetivo de este proyecto es dar a conocer el concurso SHA-3, concurso que ha transcurrido durante los últimos años y que ha promovido el Instituto Nacional de Estándares y Tecnología, también conocido como NIST, con el objetivo de encontrar el nuevo algoritmo criptográfico de función resumen SHA-3 que se utilizará de estándar de aquí en adelante. Con este fin se ha realizado un estudio sobre criptografía en general y sobre algunos de los algoritmos criptográficos de func...

An assessment of 25-hydroxyvitamin D measurements in comparability studies conducted by the Vitamin D Metabolites Quality Assurance Program.

Science.gov (United States)

Bedner, Mary; Lippa, Katrice A; Tai, Susan S-C

2013-11-15

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements, established the first accuracy-based program for improving the comparability of vitamin D metabolite measurements, the Vitamin D Metabolites Quality Assurance Program. The study samples were human serum or plasma Standard Reference Materials (SRMs) with 25-hydroxyvitamin D values that were determined at NIST. Participants evaluated the materials using immunoassay (IA), liquid chromatography (LC) with mass spectrometric detection, and LC with ultraviolet absorbance detection. NIST evaluated the results for concordance within the participant community as well as trueness relative to the NIST value. For the study materials that contain mostly 25-hydroxyvitamin D3 (25(OH)D3),the coefficient of variation (CV) for the participant results was consistently in the range from 7% to 19%, and the median values were biased high relative to the NIST values. However, for materials that contain significant concentrations of both 25-hydroxyvitamin D2 (25(OH)D2) and 25(OH)D3, the median IA results were biased lower than both the LC and the NIST values, and the CV was as high as 28%. The first interlaboratory comparison results for SRM 972a Vitamin D Metabolites in Human Serum are also reported. Relatively large within-lab and between-lab variability hinders conclusive assessments of bias and accuracy. © 2013.

Basic study on neutron activation analysis measuring short-lived nuclides (half-lives 0.7 to 100 s) using JRR-3M NAA facility

International Nuclear Information System (INIS)

Yonezawa, Chushiro; Ichimura, Shigeju; Matsue, Hideaki; Kurosawa, Tatsuya

1998-11-01

Analytical basis for neutron activation analysis (NAA) measuring nuclides of second order half-life produced by (n, γ) reaction has been studied using a neutron activation analysis facility of JRR-3M. Basic experimental conditions such as high count rate gamma-ray measurement, effects of irradiation capsule material and stability of neutron flux were examined. The analytical sensitivities and detection limits for 20 elements of which activated radionuclides have half-lives from 0.7 to 100 s were obtained. Scandium, Hf, Dy and In were elements having the highest analytical sensitivity, with detection limits down to 4.2 to 14 ng. Fluorine, of which determination by other methods is difficult, can be detected in more than 530 ng. Determination of ppm levels of F in silicon nitride powder using a single and cyclic activation methods were performed. Accuracy and precision for F determination were verified by analyzing reference materials of Opal Glass (NIST SRM91) and Oyster Tissue (NIST SRM1566a). The relationship between the detection limit of F and Al contents was also clarified. Analytical applications of high sensitive elements such as Se, Sc, Hf, In and Dy in various materials, including reference materials, were also examined and the accuracy, precision and detection limits of the present method were evaluated. (author)

Analysis of the NIST database towards the composition of vulnerabilities in attack scenarios

NARCIS (Netherlands)

Nunes Leal Franqueira, V.; van Keulen, Maurice

The composition of vulnerabilities in attack scenarios has been traditionally performed based on detailed pre- and post-conditions. Although very precise, this approach is dependent on human analysis, is time consuming, and not at all scalable. We investigate the NIST National Vulnerability Database

Aplicación del NFIS (Nist Fingerprint Image Software para la Extracción de Características de Huellas Dactilares Aplicación del NFIS (Nist Fingerprint Image Software para la Extracción de Características de Huellas Dactilares

Directory of Open Access Journals (Sweden)

Noé Mosqueda Valadez

2012-02-01

Full Text Available Este artículo presenta una descripción acerca de las huellas dactilares y sus características, así como la extracción de puntos característicos de la misma por medio del programa NFIS desarrollado por el NIST (National Institute of Standards and Technology en conjunción con el FBI (Federal Bureau of Investigation, descripción de algunas herramientas, así como un panorama general de un sistema AFAS (Automatic Fingerprint Authentification System y de un sistema AFIS (Automatic Fingerprint Identification System. This paper presents a description about the fingerprints and its characteristics, as well as the extraction of their characteristic points by means of the application of the program NFIS (NIST Fingerprint Image Software developed by the NIST (National Institute of Standards and Technology in conjunction with the FBI (Federal Bureau of Investigation, the description of some tools, as well as a general view of a system AFAS (Automatic Fingerprint Authentification System and of a system AFIS (Automatic Fingerprint Identification System.

Stability studies of arsenic, selenium, antimony and tellurium species in water, urine, fish and soil extracts using HPLC/ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Lindemann, T.; Prange, A.; Neidhart, B. [GKSS Research Centre, Geesthacht (Germany). Inst. of Physical and Chemical Analysis; Dannecker, W. [Hamburg Univ. (Germany). Inst. fuer Anorganische und Angewandte Chemie

2000-10-01

The stability of arsenic, selenium, antimony and tellurium species in water and urine (NIST SRM 2670n) as well as in extracts of fish and soil certified reference materials (DORM-2 and NIST SRM 2710) has been investigated. Stability studies were carried out with As(III), As(V), arsenobetaine, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), phenylarsonic acid (PAA), Se(IV), Se(VI), selenomethionine, Sb(III), Sb(V) and Te(VI). Speciation analysis was performed by on-line coupling of anion exchange high-performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Best storage of aqueous mixtures of the examined species was achieved at 3 C whereas at -20 C species transformation especially of selenomethionine and Sb(V) took place and a new selenium species appeared within a period of 30 days. Losses and species transformations during extraction processes were investigated. Extraction of the spiked fish material with methanol/water led to partial conversion of Sb(III), Sb(V) and selenomethionine to two new antimony and one new selenium species. The other arsenic, selenium and tellurium species were almost quantitatively extracted. For soil spiked with MMA, PAA, Se(IV) and Sb(III), recoveries after extraction with water and sulfuric acid (0.01 mol/L) were below 20%. (orig.)

Reflective Optical Chopper Used in NIST High-Power Laser Measurements

Directory of Open Access Journals (Sweden)

Cromer, Chris

2008-11-01

Full Text Available For the past ten years, NIST has used high-reflectivity, optical choppers as beamsplitters and attenuators when calibrating the absolute responsivity and response linearity of detectors used with high-power CW lasers. The chopper-based technique has several advantages over the use of wedge-shaped transparent materials (usually crystals often used as beam splitters in this type of measurement system. We describe the design, operation and calibration of these choppers. A comparison between choppers and transparent wedge beampslitters is also discussed.

Development of inspection techniques for quantitatively measuring surface contamination on SRM hardware

Science.gov (United States)

Law, R. D.

1989-01-01

A contaminant is any material or substance which is potentially undesirable or which may adversely affect any part, component, or assembly. Contamination control of SRM hardware surfaces is a serious concern, for both Thiokol and NASA, with particular concern for contaminants which may adversely affect bonding surfaces. The purpose of this study is to develop laboratory analytical techniques which will make it possible to certify the cleanliness of any designated surface, with special focus on particulates (dust, dirt, lint, etc.), oils (hydrocarbons, silicones, plasticizers, etc.), and greases (HD-2, fluorocarbon grease, etc.). The hardware surfaces of concern will include D6AC steel, aluminum alloys, anodized aluminum alloys, glass/phenolic, carbon/phenolic, NBR/asbestos-silica, and EPDM rubber.

First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay--Lp(a) SRM 2B.

Science.gov (United States)

Dati, Francesco; Tate, Jillian R; Marcovina, Santica M; Steinmetz, Armin

2004-01-01

Lipoprotein(a) is an important predictor of cardiovascular disease risk. The lack of internationally accepted standardization has impeded the broad application of this lipoprotein in laboratory medicine. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), through its Working Group on Lipoprotein(a) and together with research institutions and several diagnostic companies, have succeeded in developing an international reference material that is intended for the transfer of a lipoprotein(a) concentration to manufacturers' master calibrators. IFCC SRM 2B has recently been accepted by the WHO Expert Committee on Biological Standardization as the 'First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay'. The assigned unitage of 0.1071 nanomoles of lipoprotein(a) per vial is traceable to the consensus reference method for lipoprotein(a) and will enable conformity by diagnostic companies to the European Union's Directive on In vitro Diagnostic Medical Devices for the metrological traceability of calibrator materials.

Newly developed standard reference materials for organic contaminant analysis

Energy Technology Data Exchange (ETDEWEB)

Poster, D.; Kucklick, J.; Schantz, M.; Porter, B.; Wise, S. [National Inst. of Stand. and Technol., Gaithersburg, MD (USA). Center for Anal. Chem.

2004-09-15

The National Institute of Standards and Technology (NIST) has issued a number of Standard Reference Materials (SRM) for specified analytes. The SRMs are biota and biological related materials, sediments and particle related SRMs. The certified compounds for analysis are polychlorinated biphenyls (PCB), polycylic aromatic hydrocarbons (PAH) and their nitro-analogues, chlorinated pesticides, methylmercury, organic tin compounds, fatty acids, polybrominated biphenyl ethers (PBDE). The authors report on origin of materials and analytic methods. (uke)

Uranium isotopic composition and uranium concentration in special reference material SRM A (uranium in KCl/LiCl salt matrix)

International Nuclear Information System (INIS)

Graczyk, D.G.; Essling, A.M.; Sabau, C.S.; Smith, F.P.; Bowers, D.L.; Ackerman, J.P.

1997-07-01

To help assure that analysis data of known quality will be produced in support of demonstration programs at the Fuel Conditioning Facility at Argonne National Laboratory-West (Idaho Falls, ID), a special reference material has been prepared and characterized. Designated SRM A, the material consists of individual units of LiCl/KCl eutectic salt containing a nominal concentration of 2.5 wt. % enriched uranium. Analyses were performed at Argonne National Laboratory-East (Argonne, IL) to determine the uniformity of the material and to establish reference values for the uranium concentration and uranium isotopic composition. Ten units from a batch of approximately 190 units were analyzed by the mass spectrometric isotope dilution technique to determine their uranium concentration. These measurements provided a mean value of 2.5058 ± 0.0052 wt. % U, where the uncertainty includes estimated limits to both random and systematic errors that might have affected the measurements. Evidence was found of a small, apparently random, non-uniformity in uranium content of the individual SRM A units, which exhibits a standard deviation of 0.078% of the mean uranium concentration. Isotopic analysis of the uranium from three units, by means of thermal ionization mass spectrometry with a special, internal-standard procedure, indicated that the uranium isotopy is uniform among the pellets with a composition corresponding to 0.1115 ± 0.0006 wt. % 234 U, 19.8336 ± 0.0059 wt. % 235 U, 0.1337 ± 0.0006 wt. % 236 U, and 79.9171 ± 0.0057 wt. % 238 U

The analysis of Th in the Korean total diet sample by RNAA

International Nuclear Information System (INIS)

Chung, Yong Sam; Moon, Jong Hwa; Kang, Sang Hoon; Park, Kwang Won

1999-01-01

In order to estimate the degree of intake of 232 Th through daily diet, a korean total diet sample was collected and made after the investigation of the amount of consumption of daily diet which is dependent on the ages of 20's to 50's. For Th analysis, the RNAA method was applied and NIST SRM 1575, Pine Needle was used as quality control materials. The result of the SRM analysis was compared with a certified value. The relative error was 5%. The determination of the Th in the korean total diet sample was carried out under the same analytical condition and procedure with SRM. As a result of the korean total diet sample, the concentration of Th was in 3.4 ± 0.2 ppb and the amount of daily intake of Th by the diet is found to be 0.67 g per day. Radioactivity by Th intake was estimated to be about 2.7 mBq per person per day and annual dose equivalent was revealed as 0.73 μSv per person

Simulation of Snowmelt Runoff Using SRM Model and Comparison With Neural Networks ANN and ANFIS (Case Study: Kardeh dam basin

Directory of Open Access Journals (Sweden)

morteza akbari

2017-03-01

Full Text Available Introduction: Snowmelt runoff plays an important role in providing water and agricultural resources, especially in mountainous areas. There are different methods to simulate the process of snowmelt. Inter alia, degree-day model, based on temperature-index is more cited. Snowmelt Runoff Model is a conceptual hydrological model to simulate and predict the daily flow of rivers in the mountainous basins on the basis of comparing the accuracy of AVHRR and TM satellite images to determine snow cover in Karun Basin. Additionally, overestimation of snow-covered area decreased with increasing spatial resolution of satellite data.Studies conducted in the Zayandehrood watershed dam, showed that in the calculation of the snow map cover, changes from MODIS satellite imagery, at the time that the image does not exist, using the digital elevation model and regression analysis can provide to estimate the appropriate data from satellites. In the study of snow cover in eastern Turkey, in the mountainous regions of the Euphrates River, data from five meteorological stations and MODIS images were used with a resolution of 500 m. The results showed that satellite images have a good accuracy in estimating snow cover. In a Watershed in northern Pakistan in the period from 2000 to 2006, SRM model was used to estimate the snow cover using MODIS images. The purpose of this study was to evaluate the snowmelt runoff using remote sensing data and SRM model for flow simulation, based on statistical parameters in the Kardeh dam basin. Materials and Methods: Kardeh dam basin has an area of about 560 square kilometers and is located in the north of Mashhad. This area is in the East of Hezarmasjed – kopehdagh zone that is one of the main basins of Kashafrood. This basin is a mountainous area. About 261 km of the basin is located at above 2000 m. The lowest point of the basin is at the watershed outlet with1300 meters and the highest point in the basin, in the North West part

Liquid Scintillation counting Standardization of 22 NaCl by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-09-01

We describe a procedure for preparing a stable solution of ''22 NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4/% and an overall uncertainty of 0.35%

Determination of polybrominated diphenyl ethers in environmental standard reference materials

Energy Technology Data Exchange (ETDEWEB)

Stapleton, Heather M.; Schantz, Michele M.; Wise, Stephen A. [National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD (United States); Keller, Jennifer M.; Kucklick, John R. [National Institute of Standards and Technology, Analytical Chemistry Division, Hollings Marine Laboratory, Charleston, SC (United States); Leigh, Stefan D. [National Institute of Standards and Technology, Statistical Engineering Division, Gaithersburg, MD (United States)

2007-04-15

Standard reference materials (SRMs) are valuable tools in developing and validating analytical methods to improve quality assurance standards. The National Institute of Standards and Technology (NIST) has a long history of providing environmental SRMs with certified concentrations of organic and inorganic contaminants. Here we report on new certified and reference concentrations for 27 polybrominated diphenyl ether (PBDE) congeners in seven different SRMs: cod-liver oil, whale blubber, fish tissue (two materials), mussel tissue and sediment (two materials). PBDEs were measured in these SRMs, with the lowest concentrations measured in mussel tissue (SRM 1974b) and the highest in sediment collected from the New York/New Jersey Waterway (SRM 1944). Comparing the relative PBDE congener concentrations within the samples, we found the biota SRMs contained primarily tetrabrominated and pentabrominated diphenyl ethers, whereas the sediment SRMs contained primarily decabromodiphenyl ether (BDE 209). The cod-liver oil (SRM 1588b) and whale blubber (SRM 1945) materials were also found to contain measurable concentrations of two methoxylated PBDEs (MeO-BDEs). Certified and reference concentrations are reported for 12 PBDE congeners measured in the biota SRMs and reference values are available for two MeO-BDEs. Results from a sediment interlaboratory comparison PBDE exercise are available for the two sediment SRMs (1941b and 1944). (orig.)

Determination of total antimony and inorganic antimony species by hydride generation in situ trapping flame atomic absorption spectrometry: a new way to (ultra)trace speciation analysis

Energy Technology Data Exchange (ETDEWEB)

Henryk Matusiewicz; Magdalena Krawczyk

2008-07-01

The analytical performance of non-chromatographic coupled hydride generation, integrated atom trap (HG-IAT) atomizer flame absorption spectrometry (FAAS) systems were evaluated for the speciation analysis of antimony in environmental samples. Antimony, using formation of stibine (SbH{sub 3}) vapors were atomized in an air-acetylene flame-heated IAT. A new design of HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements was investigated. For the estimation of Sb(III) and Sb(V) concentrations in samples, the difference between the analytical sensitivities of the absorbance signals obtained for antimony hydride without and with previous treatment of samples with L-cysteine can be used. The concentration of Sb(V) was calculated by the difference between total Sb and Sb(III). A dramatic improvement in detection limit was achieved compared with that obtained using either of the atom trapping techniques, presented above, separately. This novel approach decreases the detection limit down to low pg mL{sup -1} levels. The concentration detection limit, defined as 3 times the blank standard deviation was 0.2 ng mL{sup -1}. For a 120 s in situ pre-concentration time , sensitivity enhancement compared to flame AAS, was 550 fold for Sb, using hydride generation-atom trapping technique. The accuracy of the method was verified by the use of certified reference materials (NIST SRM 2704 Buffalo River Sediment, SRM 2710 Montana Soil, SRM 1633a Coal Fly Ash, SRM 1575 Pine Needles, SRM 1643e Trace Elements in Water) and by aqueous standard calibration technique. The measured Sb content, in reference materials, were in satisfactory agreement with the certified values. The hyphenated technique was applied for antimony determinations in soil, sediment, coal fly ash, sewage and river water.

Development of protein biomarkers in cerebrospinal fluid for secondary progressive multiple sclerosis using selected reaction monitoring mass spectrometry (SRM-MS

Directory of Open Access Journals (Sweden)

Jia Yan

2012-07-01

Full Text Available Abstract Background Multiple sclerosis (MS is a chronic inflammatory disorder of the central nervous system (CNS. It involves damage to the myelin sheath surrounding axons and to the axons themselves. MS most often presents with a series of relapses and remissions but then evolves over a variable period of time into a slowly progressive form of neurological dysfunction termed secondary progressive MS (SPMS. The reasons for this change in clinical presentation are unclear. The absence of a diagnostic marker means that there is a lag time of several years before the diagnosis of SPMS can be established. At the same time, understanding the mechanisms that underlie SPMS is critical to the development of rational therapies for this untreatable stage of the disease. Results Using high performance liquid chromatography-coupled mass spectrometry (HPLC; we have established a highly specific and sensitive selected reaction monitoring (SRM assay. Our multiplexed SRM assay has facilitated the simultaneous detection of surrogate peptides originating from 26 proteins present in cerebrospinal fluid (CSF. Protein levels in CSF were generally ~200-fold lower than that in human sera. A limit of detection (LOD was determined to be as low as one femtomol. We processed and analysed CSF samples from a total of 22 patients with SPMS, 7 patients with SPMS treated with lamotrigine, 12 patients with non-inflammatory neurological disorders (NIND and 10 healthy controls (HC for the levels of these 26 selected potential protein biomarkers. Our SRM data found one protein showing significant difference between SPMS and HC, three proteins differing between SPMS and NIND, two proteins between NIND and HC, and 11 protein biomarkers showing significant difference between a lamotrigine-treated and untreated SPMS group. Principal component analysis (PCA revealed that these 26 proteins were correlated, and could be represented by four principal components. Overall, we established an

76 FR 27305 - Proposed Information Collection; Comment Request; the NIST Summer Institute for Middle School...

Science.gov (United States)

2011-05-11

...) programs designed to support middle school science teachers to participate in hands-on workshops, lectures... Gaithersburg, Maryland. The workshops provide teachers with instructional information and ideas to use in their teaching, and emphasize the measurement science done at NIST. The Program provides a world-class...

Evaluation of the sensitivity of the 'Wiley registry of tandem mass spectral data, MSforID' with MS/MS data of the 'NIST/NIH/EPA mass spectral library'.

Science.gov (United States)

Oberacher, Herbert; Whitley, Graeme; Berger, Bernd

2013-04-01

Tandem mass spectral libraries are versatile tools for small molecular identification finding application in forensic science, doping control, drug monitoring, food and environmental analysis, as well as metabolomics. Two important libraries are the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS) and the collection of MS/MS spectra part of the 2011 edition of the 'NIST/NIH/EPA Mass Spectral Library' (NIST 11 MSMS). Herein, the sensitivity and robustness of the Wiley Registry MSMS were evaluated using spectra extracted from the NIST 11 MSMS library. The sample set was found to be heterogeneous in terms of mass spectral resolution, type of CID, as well as applied collision energies. Nevertheless, sensitive compound identification with a true positive identification rate ≥95% was possible using either the MSforID Search program or the NIST MS Search program 2.0g for matching. To rate the performance of the Wiley Registry MSMS, cross-validation experiments were repeated using subcollections of NIST 11 MSMS as reference library and spectra extracted from the Wiley Registry MSMS as positive controls. Unexpectedly, with both search algorithms tested, correct results were obtained in less than 88% of cases. We examined possible causes for the results of the cross validation study. The large number of precursor ions represented by a single tandem mass spectrum only was identified as the basic cause for the comparably lower sensitivity of the NIST library. Copyright © 2013 John Wiley & Sons, Ltd.

Liquid Scintillation Counting Standardization of 22NaCl by te CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-01-01

We describe a procedure for preparing a stable solution of ''22NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4 % and an overall uncertainty of 0.35 %. (Author) 4 refs

Liquid Scintillation Counting Standardization of {sup 2}2NaCl by te CIEMAT/NIST method; Calibracion por Centelleo Liquido del ''22NaCl, mediante el metodo CIEMAT/NIST

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Grau Carles, A.; Grau Malonda, A.

1995-07-01

We describe a procedure for preparing a stable solution of ''22NaCl for liquid scintillation counting and its counting stability and spectral evolution in Insta-Gel''R is studied. The solution has been standardised in terms of activity concentration by the CIEMAT/NIST method with discrepancies between experimental and computed efficiencies lower than 0.4 % and an overall uncertainty of 0.35 %. (Author) 4 refs.

k0-INAA application at IPEN Neutron Activation Laboratory by using the k0-IAEA program: biological sample analysis

International Nuclear Information System (INIS)

Puerta, Daniel Correa

2013-01-01

The results obtained in the application of the k 0 -standardization method at LAN-IPEN for biological matrices analysis, by using the k 0 -IAEA software, provided by the International Atomic Energy Agency (IAEA), are presented. The flux parameters f and a of the IEA-R1 reactor were determined for the pneumatic irradiation facility and for one selected irradiation position, 24B/shelf2, for short and long irradiations, respectively. In order to obtain these parameters, the bare triple-monitor method with 197 Au- 96 Zr- 94 Zr was used. In order to evaluate the accuracy and precision of the methodology, the biological reference materials Peach Leaves (NIST SRM 1547), Mixed Polish Herbs (INCT-MPH-2) e Tomato Leaves (NIST SRM 1573a) were analyzed. The statistical criteria Relative Errors (bias, %), Coefficient of Variation (CV) and U-score were applied to the obtained results (mean of six replicates). The relative errors (bias, %) in relation to certified values, were, for most elements, in the range of 0 e 30. The Coefficients of Variation were below 20%, showing a good reproducibility of the results. The U-score test showed that all results, except Na in Peach Leaves and in Tomato Leaves, were within 95% confidence interval. These results point out to a promising use of the k 0 -INAA method at LAN-IPEN for biological sample analysis. (author)

Determination of tin in biological reference materials by atomic absorption spectrophotometry and neutron activation analysis

International Nuclear Information System (INIS)

Chiba, M.; Iyengar, V.; Gills, T.

1991-01-01

Because of a lack of reliable analytical techniques for the determination of tin in biological materials, there have been no reference materials certified for this element. However, the authors' experience has shown that it is feasible to use both atomic absorption and nuclear activation techniques at least for selected matrices. Therefore, an investigation was undertaken to determine tin in several biological materials such as non-fat milk powder (NBS-SRM-1549), citrus leaves (NBS-SRM-1572), total diet (NIST-SRM-1548), mixed diet (NBS-RM-8431), and USDIET-I by atomic absorption spectrophotometry (AAS) and neutron activation analysis (NAA). AAS-ashed samples were extracted with MIBK and assayed using a Perkin Elmer model 5000 apparatus. NAA was carried out by irradiating the samples at the NIST reactor in the RT-4 facility and counting with the help of a Ge(Li) detector connected to a multichannel analyzer. The concentration of tin measured by both AAS and NAA agree well for USDIET-I, total diet, citrus leaves and non-fat milk powder (the concentration ranges for tin in these matrices were from 0.0025 to 3.8 micro g/g). However, in the case of mixed diet (RM-8431), the mean values found were 47 ± 5.6 (n = 19) by AAS and 55.5 ± 2.5 (n = 6) by INAA. Since RM-8431 is not certified it is difficult to draw conclusions. For apple and peach leaves, a distillation step was required. The results were apple leaves 0.085 ± 0.015 (n = 10) by AAS and < 0.2 (n = 3) by RNAA; for peach leaves 0.077 ± 0.02 (n = 9) by AAS and < 0.1 (n = 3) by RNAA. All concentrations are expressed in micro g/g dry weight

Laser ablation inductively coupled plasma mass spectrometry for the determination of trace elements in soil

International Nuclear Information System (INIS)

Lee Yiling; Chang Chaochiang; Jiang Shiuhjen

2003-01-01

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to the determination of Cr, Cu, Zn, Cd and Pb in soil samples. The dried soil powder was pressed into a pellet for LA-ICP-MS analysis. Triton X-100 was added to work as the modifier to enhance the ion signals. The influences of instrument operating conditions (LA and ICP-MS) and pellet preparation on the ion signals were reported. For Cr determination, the ICP-MS was operated under the dynamic reaction cell mode which alleviated the mass overlap interference. Standard addition method and isotope dilution method were used for the quantitation work. The powder sample was spiked with suitable amounts of element standards and/or enriched isotopes, well-mixed, dried and then pressed into a pellet for LA-ICP-MS analysis. This method has been applied to determine Cr, Cu, Zn, Cd and Pb in NIST SRM 2711 Montana soil and NIST SRM 2709 San Joaquin soil reference materials. The analysis results were in agreement with the certified values. The precision between sample replicates was better than 5% with LA-ICP-MS method. Detection limits estimated from standard addition curves were approximately 0.9, 2, 9, 0.7 and 0.3 ng g -1 for Cr, Cu, Zn, Cd and Pb, respectively

Progress in Primary Acoustic Thermometry at NIST: 273 K to 505 K

Science.gov (United States)

Strouse, G. F.; Defibaugh, D. R.; Moldover, M. R.; Ripple, D. C.

2003-09-01

The NIST Acoustic Thermometer determines the thermodynamic temperature by measuring the speed of sound of argon in a spherical cavity. We obtained the thermodynamic temperature of three fixed points on the International Temperature Scale of 1990: the melting point of gallium [T(Ga) = 302.9146 K] and the freezing points of indium [T(In) = 429.7485 K] and tin [T(Sn) = 505.078 K]. The deviations of thermodynamic temperature from the ITS-90 defined temperatures are T - T90 = (4.7 ± 0.6) mK at T(Ga) , T - T90 = (8.8 ± 1.5) mK at T(In) , and T - T90 = (10.7 ± 3.0) mK at T(Sn) , where the uncertainties are for a coverage factor of k = 1. Our results at T(In) and T(Sn) reduce the uncertainty of T - T90 by a factor of two in this range. Both T - T90 at T(Ga) and the measured thermal expansion of the resonator between the triple point of water and T(Ga) are in excellent agreement with the 1992 determination at NIST. The dominant uncertainties in the present data come from frequency-dependent and time-dependent crosstalk between the electroacoustic transducers. We plan to reduce these uncertainties and extend this work to 800 K.

Characterization of a new candidate isotopic reference material for natural Pb using primary measurement method.

Science.gov (United States)

Nonose, Naoko; Suzuki, Toshihiro; Shin, Ki-Cheol; Miura, Tsutomu; Hioki, Akiharu

2017-06-29

A lead isotopic standard solution with natural abundance has been developed by applying a mixture of a solution of enriched 208 Pb and a solution of enriched 204 Pb ( 208 Pb- 204 Pb double spike solution) as bracketing method. The amount-of-substance ratio of 208 Pb: 204 Pb in this solution is accurately measured by applying EDTA titrimetry, which is one of the primary measurement methods, to each enriched Pb isotope solution. Also metal impurities affecting EDTA titration and minor lead isotopes contained in each enriched Pb isotope solution are quantified by ICP-SF-MS. The amount-of-substance ratio of 208 Pb: 204 Pb in the 208 Pb- 204 Pb double spike solution is 0.961959 ± 0.000056 (combined standard uncertainty; k = 1). Both the measurement of lead isotope ratios in a candidate isotopic standard solution and the correction of mass discrimination in MC-ICP-MS are carried out by coupling of a bracketing method with the 208 Pb- 204 Pb double spike solution and a thallium internal addition method, where thallium solution is added to the standard and the sample. The measured lead isotope ratios and their expanded uncertainties (k = 2) in the candidate isotopic standard solution are 18.0900 ± 0.0046 for 206 Pb: 204 Pb, 15.6278 ± 0.0036 for 207 Pb: 204 Pb, 38.0626 ± 0.0089 for 208 Pb: 204 Pb, 2.104406 ± 0.00013 for 208 Pb: 206 Pb, and 0.863888 ± 0.000036 for 207 Pb: 206 Pb. The expanded uncertainties are about one half of the stated uncertainty for NIST SRM 981, for 208 Pb: 204 Pb, 207 Pb: 204 Pb and 206 Pb: 204 Pb, or one eighth, for 208 Pb: 206 Pb and 207 Pb: 206 Pb, The combined uncertainty consists of the uncertainties due to lead isotope ratio measurements and the remaining time-drift effect of mass discrimination in MC-ICP-MS, which is not removed by the coupled correction method. In the measurement of 208 Pb: 204 Pb, 207 Pb: 204 Pb and 206 Pb: 204 Pb, the latter contribution is two or three times larger than the former. When the coupling of

On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) EC isolation procedure

Science.gov (United States)

Currie, L. A.; Kessler, J. D.

2005-10-01

The primary objective of the research reported here has been the development of a hybrid reference material (RM) to serve as a test of accuracy for elemental carbon (EC) isotopic (14C) speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of "soot" (EC), the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust), showed a range of results, but since the "truth" was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC) of measurement validity (Currie et al., 2002). Components of the new Hybrid RM (DiesApple), however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically). NIST SRM 2975 (Forklift Diesel Soot) has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves) has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char) from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK) and thermal optical transmission (TOT) methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS). As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1) both methods exhibited biomass-C "leakage"; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC) isolated contained about 3% of the original biomass-C.; (2) the initial isothermal oxidation stage of

On the isolation of elemental carbon (EC for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK EC isolation procedure

Directory of Open Access Journals (Sweden)

L. A. Currie

2005-01-01

Full Text Available The primary objective of the research reported here has been the development of a hybrid reference material (RM to serve as a test of accuracy for elemental carbon (EC isotopic (14C speciation measurements. Such measurements are vital for the quantitative apportionment of fossil and biomass sources of 'soot' (EC, the tracer of fire that has profound effects on health, atmospheric visibility, and climate. Previous studies of 14C-EC measurement quality, carried out with NIST SRM 1649a (Urban Dust, showed a range of results, but since the 'truth' was not known for this natural matrix RM, one had to rely on isotopic-chemical consistency evidence (14C in PAH, EC of measurement validity (Currie et al., 2002. Components of the new Hybrid RM (DiesApple, however, have known 14C and EC composition, and they are nearly orthogonal (isotopically and chemically. NIST SRM 2975 (Forklift Diesel Soot has little or no 14C, and its major compositional component is EC; SRM 1515 (Apple Leaves has the 14C content of biomass-C, and it has little or no EC. Thus, the Hybrid RM can serve as an absolute isotopic test for the absence of EC-mimicking pyrolysis-C (char from SRM 1515 in the EC isolate of the Hybrid RM, as well as a test for conservation of its dominant soot fraction throughout the isolation procedure. The secondary objective was to employ the Hybrid RM for the comparative evaluation of the thermal optical kinetic (TOK and thermal optical transmission (TOT methods for the isolation of EC for micro-molar carbon accelerator mass spectrometry (AMS. As part of this process, the relatively new TOK method was subjected to a critical evaluation and significant development. Key findings of our study are: (1 both methods exhibited biomass-C 'leakage'; for TOT, the EC fraction isolated for AMS contained about 8% of the original biomass-C; for TOK, the refractory carbon (RC isolated contained about 3% of the original biomass-C.; (2 the initial isothermal oxidation stage

Quality control and performance evaluation of k0-based neutron activation analysis at the Portuguese research reactor

International Nuclear Information System (INIS)

Dung, H.M.; Freitas, M.C.; Blaauw, M.; Almeida, S.M.; Dionisio, I.; Canha, N.H.

2010-01-01

The quality control (QC) and performance evaluation for the k 0 -based neutron activation analysis (k 0 -NAA) at the Portuguese research reactor (RPI) has been developed with the intention of using the method to meet the demands of trace element analysis for the applications in environmental, epidemiological and nutritional studies amongst others. The QC and performance evaluation include the following aspects: (1) estimation of the overall/combined standard uncertainty from the primary uncertainty sources; (2) validation of the method using a synthetic multi-element standard (SMELS); and (3) analysis of the certified reference materials from the National Institute of Standards and Technology (USA): NIST-SRM-1633a and NIST-SRM-1648 and the reference material from the International Atomic Energy Agency: IAEA-RM-336, for the purpose of controlling the overall accuracy and precision of the analytical results. The obtained results revealed that the k 0 -NAA method established at the RPI was fit for the purpose. The overall/combined standard uncertainty was estimated for elements of interest in the intended applications. The laboratory's analytical results as compared to the assigned values with the bias were less than 12% for most elements, except for a few elements which biased within 13-18%. The u-score values for most elements were less than |1.64|, except for Co, La and Ti within |1.64|-|1.96| and Sc, Cr, K and Sb within |1.96|-|2.58|. The NIST-1633a was also analyzed over 14 months for the purpose of evaluating the reproducibility of the method. The quality factors of k 0 -NAA established at RPI were evaluated, proving that the method meets the requirements of trace element analysis, which is also considering the method's performance for which the k 0 -NAA affords a specific, rapid and convenient capability for the intended applications.

Use of nuclear and nuclear-related analytical techniques in studies of trace and minor elements in air pollution

International Nuclear Information System (INIS)

Smodis, Borut; Stropnik, Boris

1994-01-01

Among nuclear and nuclear-related analytical techniques, neutron activation and X-ray fluorescence analysis are particularly useful for environmental studies owing to their non-destructive character and multi-element capability. In this work, procedures for k o -standardized instrumental neutron activation analysis (INAA) and energy-dispersive X-ray fluorescence (EDXRF) spectrometry for trace and minor elements in air pollution studies were investigated. The methods applied were validated by the analysis of suitable reference materials. Using INAA, 20 experimentally obtained elemental values out of 21 certified and all 29 experimentally obtained values compared with 'consensus' values (for the elements where no certified numbers are available) in two SRMs were statistically indistinguishable. Also, the contents of 28 elements in candidate NIST SRM 1573a Tomato Leaves are reported. The EDXRF results were statistically indistinguishable from certified values for eight out of nine elements in NIST SRM 3087. The detection limit for this method is around at 0.1 μg cm -2 per element, so in BCR CRM No. 128, which is intended for ambient air pollution data, only Fe and Zn out of 14 elements reported in the certificate were detected with acceptable precision (i.e., 10%) owing to the very low air particulate matter loading, lying in the region of only 250 μg cm -2 . (Author)

Re-evaluation and extension of the scope of elements in US Geological Survey Standard Reference Water Samples

Science.gov (United States)

Peart, D.B.; Antweiler, Ronald C.; Taylor, Howard E.; Roth, D.A.; Brinton, T.I.

1998-01-01

More than 100 US Geological Survey (USGS) Standard Reference Water Samples (SRWSs) were analyzed for numerous trace constituents, including Al, As, B, Ba, Be, Bi, Br, Cd, Cr, Co, Cu, I, Fe, Pb, Li, Mn, Mo, Ni, Rb, Sb, Se, Sr, Te, Tl, U, V, Zn and major elements (Ca, Mg, Na, SiO2, SO4, Cl) by inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. In addition, 15 USGS SRWSs and National Institute of Standards and Technology (NIST) standard reference material (SRM) 1641b were analyzed for mercury using cold vapor atomic fluorescence spectrometry. Also USGS SRWS Hg-7 was analyzed using isotope dilution-inductively coupled plasma mass spectrometry. The results were compared with the reported certified values of the following standard reference materials: NIST SRM 1643a, 1643b, 1643c and 1643d and National Research Council of Canada Riverine Water Reference Materials for Trace Metals SLRS-1, SLRS-2 and SLRS-3. New concentration values for trace and major elements in the SRWSs, traceable to the certified standards, are reported. Additional concentration values are reported for elements that were neither previously published for the SRWSs nor traceable to the certified reference materials. Robust statistical procedures were used that were insensitive to outliers. These data can be used for quality assurance/quality control purposes in analytical laboratories.

Analysis of alpha-synuclein in malignant melanoma - development of a SRM quantification assay.

Directory of Open Access Journals (Sweden)

Charlotte Welinder

Full Text Available Globally, malignant melanoma shows a steady increase in the incidence among cancer diseases. Malignant melanoma represents a cancer type where currently no biomarker or diagnostics is available to identify disease stage, progression of disease or personalized medicine treatment. The aim of this study was to assess the tissue expression of alpha-synuclein, a protein implicated in several disease processes, in metastatic tissues from malignant melanoma patients. A targeted Selected Reaction Monitoring (SRM assay was developed and utilized together with stable isotope labeling for the relative quantification of two target peptides of alpha-synuclein. Analysis of alpha-synuclein protein was then performed in ten metastatic tissue samples from the Lund Melanoma Biobank. The calibration curve using peak area ratio (heavy/light versus concentration ratios showed linear regression over three orders of magnitude, for both of the selected target peptide sequences. In support of the measurements of specific protein expression levels, we also observed significant correlation between the protein and mRNA levels of alpha-synuclein in these tissues. Investigating levels of tissue alpha-synuclein may add novel aspect to biomarker development in melanoma, help to understand disease mechanisms and ultimately contribute to discriminate melanoma patients with different prognosis.

Mechanical properties, microstructure and magnetic properties of composite magnet base on SrO.6Fe_2O_3 (SRM)-thermoplastic and thermoset polymer

International Nuclear Information System (INIS)

Grace Tj Sulungbudi; Aloma Karo Karo; Mujamilah; Sudirman

2010-01-01

The use of magnets in industrial applications do not always require high magnetic properties. Therefore, the use of polymer as a matrix that serves as a binder can be applied to obtain lightweight, flexible and cheap composite magnet. This report discuss composite magnet base on SrO.6Fe_2O_3(SRM)-thermoplastic and thermoset polymer. Thermoplastic polymer consist of polypropylene (PP) type of PP2 and PP10 and polyethylene (PE) type of LDPE were used. For thermoset polymer, epoxy and polyester were used. Synthesis of composite magnet based on thermoplastic polymer (PP2, PP10, LDPE) were carried using the blending method, while the thermoset composites magnet using casting method. Thermoplastic composite magnets were prepared with compositions of 50, 41, 38, 33 and 29 % weight of SRM with the blending temperature of 160 °C for LDPE and 180 °C for PP2 and PP10. For thermoset composite magnets, the compositions were 30, 40, 50 and 60 % by weight of SRM. The mechanical test conducted include tensile strength and elongation at break. Microstructure on the surface of the composite materials were observed using SEM (Scanning Electron Microscope) and the magnetic properties were measured using VSM (Vibrating Sample Magnetometer). The SEM results showed the formation of flat shape powder particle with size of 1.6 µm. In general, the mechanical properties of polypropylene polymer composite magnet are better than that using polyethylene (LDPE) binder. For polypropylene binder PP10 is better than PP2. Magnetic properties are not significantly affected by the change of polymer or binder types. (author)

Advancing Smart Grid Interoperability and Implementing NIST's Interoperability Roadmap

Energy Technology Data Exchange (ETDEWEB)

Basso,T.; DeBlasio, R.

2010-04-01

The IEEE American National Standards project P2030TM addressing smart grid interoperability and the IEEE 1547 series of standards addressing distributed resources interconnection with the grid have been identified in priority action plans in the Report to NIST on the Smart Grid Interoperability Standards Roadmap. This paper presents the status of the IEEE P2030 development, the IEEE 1547 series of standards publications and drafts, and provides insight on systems integration and grid infrastructure. The P2030 and 1547 series of standards are sponsored by IEEE Standards Coordinating Committee 21.

Dissemination of 3D Visualizations of Complex Function Data for the NIST Digital Library of Mathematical Functions

Directory of Open Access Journals (Sweden)

Qiming Wang

2007-03-01

Full Text Available The National Institute of Standards and Technology (NIST is developing a digital library to replace the widely used National Bureau of Standards Handbook of Mathematical Functions published in 1964. The NIST Digital Library of Mathematical Functions (DLMF will include formulas, methods of computation, references, and links to software for over forty functions. It will be published both in hardcopy format and as a website featuring interactive navigation, a mathematical equation search, 2D graphics, and dynamic interactive 3D visualizations. This paper focuses on the development and accessibility of the 3D visualizations for the digital library. We examine the techniques needed to produce accurate computations of function data, and through a careful evaluation of several prototypes, we address the advantages and disadvantages of using various technologies, including the Virtual Reality Modeling Language (VRML, interactive embedded graphics, and video capture to render and disseminate the visualizations in an environment accessible to users on various platforms.

Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II

Science.gov (United States)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2014-09-01

Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

Quantitative 3D elemental analysis inside plant roots by means of synchrotron confocal micro X-ray fluorescence

Science.gov (United States)

Terzano, R.; Vekemans, B.; Tomasi, N.; Spagnuolo, M.; Schoonjans, T.; Vincze, L.; Pinton, R.; Cesco, S.; Ruggiero, P.

2009-04-01

The knowledge of the distribution and concentration of elements within plants is a fundamental step to better understand how these plants uptake specific elements from the medium of growth and how they manage acquisition and compartmentalisation of nutrients as well as toxic metals. For some elements, either nutrients or toxicants, it can be of relevance to know their concentration level within microscopic volumes in plant organs, where they are stored or accumulated. Usually, this type of microscopic analysis requires complex cutting procedures and extensive sample manipulations. In this research, the technique of synchrotron micro X-ray fluorescence in the confocal mode was applied to image the distribution of elements in selected key-planes of tomato roots without the need of any sample preparation, except washing and freeze-drying. Using this method, a first polycapillary lens focussed the X-ray beam with an energy of 12.4 keV down to a 20 µm beam that is penetrating the sample, and a second polycapillary half-lens, that was positioned at the detection side at 90 degrees to the first polycapillary, could then restrict further the view on this irradiated volume to a defined microscopic volume (typically 20x20x20 µm3) from which the induced fluorescent radiation is finally collected by the energy dispersive detector. In this way, it was possible to investigate the concentration levels of some elements such as K, Ca, Mn, Fe, Cu and Zn within the roots of tomato plants. The quantification was performed by means of a dedicated XRF Fundamental Parameter (FP) method in order to calculate the concentrations of trace elements within the analysed plants. Utilizing fundamental atomic parameters, the applied FP method is taking into account the influence of sample self-absorption and especially the specific detection processes by the polycapillary lens. Quantification was assessed and validated by using different standards: NIST SRM 1573a (trace elements in tomato leaves

Monte Carlo Uncertainty Quantification Using Quasi-1D SRM Ballistic Model

Directory of Open Access Journals (Sweden)

Davide Viganò

2016-01-01

Full Text Available Compactness, reliability, readiness, and construction simplicity of solid rocket motors make them very appealing for commercial launcher missions and embarked systems. Solid propulsion grants high thrust-to-weight ratio, high volumetric specific impulse, and a Technology Readiness Level of 9. However, solid rocket systems are missing any throttling capability at run-time, since pressure-time evolution is defined at the design phase. This lack of mission flexibility makes their missions sensitive to deviations of performance from nominal behavior. For this reason, the reliability of predictions and reproducibility of performances represent a primary goal in this field. This paper presents an analysis of SRM performance uncertainties throughout the implementation of a quasi-1D numerical model of motor internal ballistics based on Shapiro’s equations. The code is coupled with a Monte Carlo algorithm to evaluate statistics and propagation of some peculiar uncertainties from design data to rocker performance parameters. The model has been set for the reproduction of a small-scale rocket motor, discussing a set of parametric investigations on uncertainty propagation across the ballistic model.

Is it possible to agree on a value for inorganic arsenic in food? The outcome of IMEP-112

DEFF Research Database (Denmark)

Calle, M. B. de la; Baer, I.; Robouch, P.

2012-01-01

. This article presents the results of the 12th proficiency test organised by the EU-RL-HM (IMEP-112) that focused on the determination of total and inorganic arsenic in wheat, vegetable food and algae. The test items used in this exercise were: wheat sampled in a field with a high concentration of arsenic...... in the soil, spinach (SRM 1570a from NIST) and an algae candidate reference material. Participation in this exercise was open to laboratories from all around the world to be able to judge the state of the art of the determination of total and, more in particular, inorganic arsenic in several food commodities...... in the algae test material....

Determination of Chloride in Infant Formula and Adult/Pediatric Nutritional Formula by Potentiometric Titration: Single-Laboratory Validation, First Action 2015.07.

Science.gov (United States)

Bolong, Wu; Fengxia, Zhang; Xiaoning, Ma; Fengjuan, Zhou; Brunelle, Sharon L

2016-01-01

A potentiometric method for determination of chloride was validated against AOAC Standard Method Performance Requirement (SMPR(®)) 2014.015. Ten AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) matrixes, including National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1849a, were tested in duplicate on 6 independent days. The repeatability (RSDr) ranged from 0.43 to 1.34%, and the intermediate reproducibility (RSDiR) ranged from 0.80 to 3.04%. All results for NIST SRM 1849a were within the range of the certified concentration (701 ± 17 mg/100 g). Recovery was demonstrated with two overspike levels, 50 and 100%, in the 10 SPIFAN matrixes. Samples were tested in duplicate on 3 different days, and all results were within the SMPR requirement of 95 to 105%. The LOQs of the method for powdered products and ready-to-feed or reconstituted products were 20 mg/100 g and 2.2 mg/100 mL, respectively. A wide analytical range from the LOQ to 99.5% chlorine content can be reached with an appropriate dilution factor, but in practice, the upper analytical value observed in routine matrix testing was approximately 1080 mg/100 g in skim milk powder. This is a rapid, simple, and reliable chlorine-testing method applicable to infant formula, adult nutritionals, and ingredients used in these dairy-based products, such as skim milk powder, desalted whey powder, whey protein powder, and whole milk powder.

Performance of the advanced cold neutron source and optics upgrades at the NIST Research Reactor

International Nuclear Information System (INIS)

Williams, R.E.; Kopetka, P.; Cook, J.C.; Rowe, J.M.

2003-01-01

On March 6, 2002, the NIST Research Reactor resumed routine operation following a six-month shutdown for facility upgrades and maintenance. During the shutdown, the original liquid hydrogen cold neutron source was removed, and the advanced cold source was installed. An optical filter was installed on one of the neutron guides, NG-3, replacing a crystal filter for the 30-m SANS instrument and the guide used between the chopper disks of the Disk Chopper time-of-flight Spectrometer (DCS) installed on NG-4 has been recently reconfigured. Additional improvements in the neutron optics of various instruments are being made. The advanced liquid hydrogen cold neutron source performs as expected, nearly doubling the flux available to most instruments. The measured gains range from about 1.4 at 2 A, to over a factor of two at 15 A. Also as expected, the heat load in the new source increased to 1200 watts, but the previously existing refrigerator has easily accommodated the increase. With intensity gains of a factor of two in the important long wavelength region of the spectrum, the advanced cold source significantly enhances the measurement capability of the cold neutron scattering instrumentation at NIST. The optical filter on NG-3 is also very successful; the 30-m SANS has an additional gain of two at 17 A. A system of refracting lenses and prisms near the SANS sample position has made possible measurements at low Q (0.0005 A -1 ) that were previously not feasible. The DCS has also seen additional intensity gain factors in excess of two for the majority of experiments and at short neutron wavelengths the gains exceed three. In addition, two new triple axis spectrometers will feature double-focusing monochromators in order to exploit the full size of the available thermal and cold neutron beam tubes. The success of the advanced cold source and enhanced neutron optics contributed to the recognition of the NIST Center for Neutron Research as 'the premiere neutron scattering

k{sub 0}-INAA application at IPEN Neutron Activation Laboratory by using the k{sub 0}-IAEA program: biological sample analysis; Aplicacao do metodo k{sub 0}-INAA no Laboratorio de Analise por Ativacao com Neutrons do IPEN utilizando o programa k{sub 0}-IAEA: analise de amostras biologicas

Energy Technology Data Exchange (ETDEWEB)

Puerta, Daniel Correa

2013-07-01

The results obtained in the application of the k{sub 0}-standardization method at LAN-IPEN for biological matrices analysis, by using the k{sub 0}-IAEA software, provided by the International Atomic Energy Agency (IAEA), are presented. The flux parameters f and a of the IEA-R1 reactor were determined for the pneumatic irradiation facility and for one selected irradiation position, 24B/shelf2, for short and long irradiations, respectively. In order to obtain these parameters, the bare triple-monitor method with {sup 197}Au-{sup 96}Zr-{sup 94}Zr was used. In order to evaluate the accuracy and precision of the methodology, the biological reference materials Peach Leaves (NIST SRM 1547), Mixed Polish Herbs (INCT-MPH-2) e Tomato Leaves (NIST SRM 1573a) were analyzed. The statistical criteria Relative Errors (bias, %), Coefficient of Variation (CV) and U-score were applied to the obtained results (mean of six replicates). The relative errors (bias, %) in relation to certified values, were, for most elements, in the range of 0 e 30. The Coefficients of Variation were below 20%, showing a good reproducibility of the results. The U-score test showed that all results, except Na in Peach Leaves and in Tomato Leaves, were within 95% confidence interval. These results point out to a promising use of the k{sub 0}-INAA method at LAN-IPEN for biological sample analysis. (author)

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

International Nuclear Information System (INIS)

Bergstrom, P

2016-01-01

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, P [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States)

2016-06-15

Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

76 FR 67418 - Request for Comments on NIST Special Publication 500-293, US Government Cloud Computing...

Science.gov (United States)

2011-11-01

...-1659-01] Request for Comments on NIST Special Publication 500-293, US Government Cloud Computing... Publication 500-293, US Government Cloud Computing Technology Roadmap, Release 1.0 (Draft). This document is... (USG) agencies to accelerate their adoption of cloud computing. The roadmap has been developed through...

Mercury determination in geological samples using radiochemical separation

International Nuclear Information System (INIS)

Goncalves, Cristina; Favaro, Deborah I.T.

1997-01-01

In this work, a radiochemical procedure is presented to increase the neutron activation analysis sensitivity. After irradiation, geological reference materials - Buffalo River Sediment (BRS- - NIST SRM 2704), Lake Sediment (BCR - CRM 280) and GXR-5 (USGS - AEG) - were leached with aqua regia in a Parr bomb placed in a domestic microwave oven and then bismuth diethyl dithiocarbamate was used to pre concentrate mercury by solvent extraction. This procedure eliminates the interference from 279 keV Se-75 photopeak and background radiation from 511 keV Cu-64 photopeak. (author). 15 refs., 2 figs., 1 tab

Analysis of Mexican cigarettes by INAA

International Nuclear Information System (INIS)

Martinez, T.; Lartigue, J.; Navarrete, M.; Morales, O.Y.; Aguilar, F.; Cuapio, L.A.; Lopez, C.

2008-01-01

Due to large consumption of tobacco in Mexico and in order to complement previous work performed by total reflection X-ray fluorescence, the present study has determined 15 elements by INAA in 9 cigarettes brands being marketed in Mexico. As a part of a Quality Control Program, NIST standard reference materials (SRM) and an IAEA reference material were analyzed to confirm the accuracy and reproducibility. Average of As and Cd were 0.56 and 1.15 μg x g -1 , respectively, in the range of those of foreign brands. (author)

Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

Energy Technology Data Exchange (ETDEWEB)

Krausová, Ivana [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Mizera, Jiří, E-mail: mizera@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V Holešovičkách 41, 182 09 Praha 8 (Czech Republic); Řanda, Zdeněk; Chvátil, David; Krist, Pavel [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic)

2015-01-01

Reliable determination of low concentrations of fluorine in geological and coal samples is difficult. It usually requires tedious decomposition and dissolution of the sample followed by chemical conversion of fluorine into its anionic form. The present paper examines possibilities of non-destructive determination of fluorine, mainly in minerals, rocks and coal, by instrumental photon activation analysis (IPAA) using the MT-25 microtron. The fluorine assay consists of counting the positron–electron annihilation line of {sup 18}F at 511 keV, which is a product of the photonuclear reaction {sup 19}F(γ, n){sup 18}F and a pure positron emitter. The assay is complicated by the simultaneous formation of other positron emitters. The main contributors to interference in geological samples are from {sup 45}Ti and {sup 34m}Cl, whereas those from {sup 44}Sc and {sup 89}Zr are minor. Optimizing beam energy and irradiation-decay-counting times, together with using interfering element calibration standards, allowed reliable IPAA determination of fluorine in selected USGS and CRPG geochemical reference materials, NIST coal reference materials, and NIST RM 8414 Bovine Muscle. In agreement with the published data obtained by PIGE, the results of the F assay by IPAA have revealed erroneous reference values provided for the NIST reference materials SRM 1632 Bituminous Coal and RM 8414 Bovine Muscle. The detection limits in rock and coal samples are in the range of 10–100 μg g{sup −1}.

Sequencing Analysis of Mutant Allele $cdc$28-$srm$ of Protein Kinase CDC28 and Molecular Dynamics Study of Glycine-Rich Loop in Wild-Type and Mutant Allele G16S of CDK2 as Model

CERN Document Server

Koltovaya, N A; Kholmurodov, Kh T; Kretov, D A

2005-01-01

The central role that cyclin-dependent kinases play in the timing of cell division and the high incidence of genetic alteration of CDKs or deregulation of CDK inhibitors in a number of cancers make CDC28 of the yeast \\textit{Saccharomyces cerevisiae }very attractive model for studies of mechanisms of CDK regulation. Earlier it was found that certain gene mutations including \\textit{cdc28-srm} affect cell cycle progression, maintenance of different genetic structures and increase cell sensitivity to ionizing radiation. A~\\textit{cdc28-srm} mutation is not temperature-sensitive mutation and differs from the known \\textit{cdc28-ts }mutations because it has the evident phenotypic manifestations at 30 $^{\\circ}$C. Sequencing analysis of \\textit{cdc28-srm} revealed a single nucleotide substitution G20S. This is a third glycine in a conserved sequence GxGxxG in the G-rich loop positioned opposite the activation T-loop. Despite its demonstrated importance, the role of the G-loop has remained unclear. The crystal stru...

An advanced liquid hydrogen cold source for the NIST research reactor

International Nuclear Information System (INIS)

Williams, R.E.; Kopetka, P.; Rowe, J.M.

1999-01-01

A second-generation liquid hydrogen cold neutron source is currently being fabricated and will be installed in the NIST reactor early next year. The existing source has operated very successfully over the last four years, providing a six-fold increase in the cold neutron yield compared to the previous heavy ice source. The design of the new source is based on our operating experience with the existing LH 2 source and extensive neutron transport calculations using improved MCNP modeling and computational capabilities. Enhanced mechanical design and manufacturing tools are exploited in the fabrication of the advanced source, which is expected to nearly double the yield of the existing LH 2 source. (author)

Improvement of the Torque-Speed Performance and Drive Efficiency in an SRM Using an Optimal Torque Sharing Function

Directory of Open Access Journals (Sweden)

Wei Ye

2018-05-01

Full Text Available In this paper, by evaluating the extreme value of the qth-power current, a torque sharing function (TSF family for reducing the torque ripples in the switched reluctance motor (SRM is proposed. The optimization criteria of the TSF has two secondary objectives, including the maximization of the torque-speed range and the minimization of copper loss. The evaluation indices in terms of the peak phase current, the rms (root mean square phase current, and the torque ripple factor are compared between the proposed TSF family and four conventional TSFs including linear, sinusoidal, exponential, and cubic TSFs. An optimization objective function that combines the maximum absolute value of the rate-of-change of the flux linkage (MAV-RCFL and the qth-power of current is proposed and a weighting factor is used to balance the influence of the two optimization objectives. An optimal TSF can be easily obtained by solving the optimization problem from the TSF family. The proposed TSF is validated by using simulations and experiments with a three-phase 6/4 SRM with 7.5 kW, 3000 rpm, and 270 V DC-link voltage. The dynamic simulation model is implemented in Matlab/Simulink. The results demonstrate the validity and superiority of the proposed control method; the optimal TSF provides better torque-speed performance, and a better reduction in copper loss and torque ripples at high speed, as compared to conventional TSFs.

Application of Neutron Activation Analysis to the determination of essential and toxic elements in agroindustrial by-products employed in animal feeding

International Nuclear Information System (INIS)

Teruya, Carla Mitie

1999-01-01

In the present work the concentrations of essential elements Ca (calcium), CI (chlorine), K (potassium), Mg (magnesium), Na (sodium), Co (cobalt), Cr (chromium), Cu (copper), Fe (iron), Mn (manganese). Mo (molybdenum), Se (selenium), V (vanadium) and Zn (zinc), the toxic elements As (arsenic), Cd (cadmium) and Hg (mercury) and the elements without defined functions to the animal metabolism, such as Br (bromine), Eu (europium). La (lanthanum), Rb (rubidium), Sb (antinomies), Sc (scandium), Ta (tantalum), Th (thorium) and U (uranium) were determined in agroindustrial by-products employed in animal feeding by instrumental neutron activation analysis (INAA). Forty samples of agroindustrial by-products were analyzed, six of which are from animal origin and the others are from vegetable origin. All these materials are widely used in bovine feeding, mainly in dry season, when the forage become scarce. The precision and accuracy of the method were evaluated by means of analysis of the following certified reference materials: Rice Flour NIES-CRM-10C, Pig Kidney BCR-CRM, Oyster Tissue NIST-SRM-1566a e Buffalo River Sediment NIST-SRM-2704. The results, in general, are lower than 10 %. The results for the most of essential minerals were lower than the toxic limit for animals, and they reached the minimum requirements for domestic animals, although some agroindustrial by-products showed concentrations lower than the requirement. For all samples, the concentrations of toxic minerals were lower than the toxic limit (author)

Irradiation positions for fission-track dating in the University of Pavia TRIGA Mark II nuclear reactor

International Nuclear Information System (INIS)

Oddone, Massimo; Meloni, Sandro; Balestrieri, Maria Laura; Bigazzi, Giulio

2002-01-01

An irradiation position arranged is described in the present paper for fission-track dating in the Triga Mark II reactor of the University of Pavia. Fluence values determined using the NIST glass standard SRM 962a for fission-track dating and the traditional metal foils are compared. Relatively good neutron thermalization (φ th /φ f = 0.956) and lack of significant fluence spatial gradients are good factors for fission-track dating. Finally, international age standards (or putative age standards) irradiated in this new position yielded results consistent with independent reference ages. (author)

Development of a method based on inductively coupled plasma-dynamic reaction cell-mass spectrometry for the simultaneous determination of phosphorus, calcium and strontium in bone and dental tissue

International Nuclear Information System (INIS)

De Muynck, David; Vanhaecke, Frank

2009-01-01

A method, based on the use of a quadrupole-based inductively coupled plasma-mass spectrometry instrument equipped with a quadrupole-based collision/reaction cell (dynamic reaction cell, DRC), was developed for the simultaneous determination of phosphorus, calcium and strontium in bone and dental (enamel and dentine) tissue. The use of NH 3 , introduced at a gas flow rate of 0.8 mL min -1 in the dynamic reaction cell, combined with a rejection parameter q (RPq) setting of 0.65, allows interference-free determination of calcium via its low-abundant isotopes 42 Ca, 43 Ca and 44 Ca, and of strontium via its isotopes 86 Sr and 88 Sr that are freed from overlap due to the occurrence of ArCa + and/or Ca 2 + ions. Also the determination of phosphorus ( 31 P, mono-isotopic) was shown to be achievable using the same dynamic reaction cell operating conditions. The bone certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for validation of the measurement protocol that was shown capable of providing accurate and reproducible results. Detection limits of P, Ca and Sr in dental tissue digests were established as 3 μg L -1 for P, 2 μg L -1 for Ca and 0.2 μg L -1 for Sr. This method can be used to simultaneously (i) evaluate the impact of diagenesis on the elemental and isotopic composition of buried skeletal tissue via its Ca/P ratio and (ii) determine its Sr concentration. The measurement protocol was demonstrated as fit-for-purpose by the analysis of a set of teeth of archaeological interest for their Ca/P ratio and Sr concentration.

NIST ThermoData Engine: Extension to Solvent Design and Propagation of Uncertainties for Process Simulation

DEFF Research Database (Denmark)

Diky, Vladimir; Chirico, Robert D.; Muzny, Chris

ThermoData Engine (TDE, NIST Standard Reference Databases 103a and 103b) is the first product that implements the concept of Dynamic Data Evaluation in the fields of thermophysics and thermochemistry, which includes maintaining the comprehensive and up-to-date database of experimentally measured ...... uncertainties, curve deviations, and inadequacies of the models. Uncertainty analysis shows relative contributions to the total uncertainty from each component and pair of components....

Estimation of neutron mean wavelength from rocking curve dataThis work is a contribution of NIST, an agency of the US Government, and not subject to copyright laws.

Science.gov (United States)

Coakley, K. J.; Chowdhuri, Z.; Snow, W. M.; Richardson, J. M.; Dewey, M. S.

2003-01-01

At NIST, an in-beam neutron lifetime experiment is underway. In part of the experiment, a neutron detector is calibrated. The accuracy of the detector calibration depends, in part, on how accurately the mean wavelength of a neutron beam can be estimated from rocking curve data. Based on a stochastic model for neutron scattering, we simulate rocking curve data. To speed up the simulation, an importance sampling method is used. For the cases studied, importance sampling reduces the execution time of the simulation code by over a factor of 500. For simulated data, the statistical bias of the mean wavelength estimate is found to be 0.004%. This work is a contribution of NIST, an agency of the US Government, and not subject to copyright laws.

41Ca standardization by the CIEMAT/NIST LSC method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Los Arcos, J.M.

1996-01-01

A procedure for the liquid scintillation counting standardization of the electron-capture nuclide 41 Ca has been successfully developed and applied with 41 CaCl 2 and 41 Ca-(HDEHP) n samples synthesized in the laboratory from 41 CaCO 3 supplied by Oak Ridge National Laboratory. Six scintillators were tested: the organic samples were stable in toluene-alcohol, Ultima-Gold TM and HiSafe III TM for 30 d, whereas the inorganic samples were only stable in toluene-alcohol and HiSafe III TM for the same period of time. Despite of the low counting efficiencies (1%-13%) due to the very low-energy of less than 3.6 keV of the X-rays and Auger electrons of 41 Ca, the stable samples were standardized by the CIEMAT/NIST method to a combined uncertainty of 2.4% over a range of figures of merit of 1.75 to 7.25 ( 3 H equivalent efficiency of 40% to 7%). (orig.)

Exploring a Black Body Source as an Absolute Radiometric Calibration Standard and Comparison with a NIST Traced Lamp Standard

Science.gov (United States)

Green, Robert O.; Chrien, Thomas; Sarture, Chuck

2001-01-01

Radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is required for the scientific research and application objectives pursued with the spectroscopic measurements. Specifically calibration is required for: inter-comparison of AVIRIS data measured at different locations and at different times; analysis of AVIRIS data with data measured by other instruments; and analysis of AVIRIS data in conjunction with computer models. The primary effect of radiometric calibration is conversion of AVIRIS instrument response values (digitized numbers, or DN) to units of absolute radiance. For example, a figure shows the instrument response spectrum measured by AVIRIS over a portion of Rogers Dry Lake, California, and another figure shows the same spectrum calibrated to radiance. Only the calibrated spectrum may be quantitatively analyzed for science research and application objectives. Since the initial development of the AVIRIS instrument-radiometric calibration has been based upon a 1000-W irradiance lamp with a calibration traced to the National Institute of Standards and Technology (NIST). There are several advantages to this irradiance-lamp calibration approach. First, the considerable effort of NIST backs up the calibration. Second, by changing the distance to the lamp, the output can closely span the radiance levels measured by AVIRIS. Third, this type of standard is widely used. Fourth, these calibrated lamps are comparatively inexpensive. Conversely, there are several disadvantages to this approach as well. First, the lamp is not a primary standard. Second, the lamp output characteristics may change in an unknown manner through time. Third, it is difficult to assess, constrain, or improve the calibration uncertainty delivered with the lamp. In an attempt to explore the effect and potentially address some of these disadvantages a set of analyses and measurements comparing an irradiance lamp with a black-body source have been completed

Microwave assisted digestion of atmospheric aerosol samples followed by inductively coupled plasma mass spectrometry determination of trace elements

Energy Technology Data Exchange (ETDEWEB)

Swami, K.; Judd, C.D.; Orsini, J.; Yang, K.X. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Husain, L. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Dept. of Environmental Health and Toxicology, State Univ. of New York, Albany (United States)

2001-01-01

A microwave digestion method in a closed vessel was developed for the determination of trace metals in atmospheric aerosols using inductively coupled plasma mass spectrometry (ICP-MS). A recovery study for the elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, and Pb was conducted using multi-elemental standard solutions, NIST 1633b Trace Elements in Coal Fly Ash, and NIST 1648 Urban Particulate Matter. A simple digestion method using only HNO{sub 3}/H{sub 2}O{sub 2}gave good recoveries (90%-108%) for all elements except Cr in SRM 1648, but yielded low recoveries for SRM 1633b. A more robust method using HNO {sub 3}/H {sub 2}O {sub 2}/HF/H {sub 3}BO {sub 3} yielded higher recoveries (82%-103%) for the lighter elements (V - Zn) in SRM 1633b, and improved the Cr recovery in SRM 1648, but decreased the Se recovery in both SRMs. A comparative analysis of aerosol samples obtained at a remote mountain location Nathiagali, Pakistan (2.5 km above mean sea level), and Mayville, New York, downwind from the highly industrialized Midwestern United States, was carried out using Instrumental Neutron Activation Analysis (INAA) for the elements Cr, Mn, Fe, Co, Zn, As, Se, and Sb. The simple digestion method yielded excellent agreement for Cr, Fe, Zn, As, Se, and Sb, with slopes of the ICP-MS vs. INAA regressions of 0.90-1.00 and R {sup 2} values of 0.96-1.00. The regressions for Mn and Co had slopes of 0.82 and 0.84 with R {sup 2} values of 0.83 and 0.82, respectively. Addition of HF/H {sub 3}BO {sub 3} did not improve the correlation for any of the elements and degraded the precision somewhat. The technique provides sensitivity and accuracy for trace elements in relatively small aerosol samples used in atmospheric chemistry studies related to SO {sub 2} oxidation in cloud droplets. The ability to determine concentrations of a very large number of elements from a single analysis will permit source apportionment of various trace pollutants and hence strategies to control the

Proton induced x-ray emission analysis of trace elements in thick bread samples

International Nuclear Information System (INIS)

Mohamed Baker Al-bedri; Ikram Jameel Abdul Ghani; Ibrahim Abdul Rahman Al-aghil

2009-01-01

Proton induced X-ray emission (PIXE) technique has been used for identification and quantitative analysis of the elemental concentration in thick bread samples. Bread samples were air-oven dried at 60degC and milled in a clean agate mortar to homogenize the sample and pressed into a pellet. PIXE technique relies on the analysis of the energy spectra of the characteristic X-ray emitted from the thick bread sample and the orchard leaf standard (NIST-SRM-1571) bombarded with 2.0 MeV protons. The concentration of the elements (Cl, K, Ca, Mn, Fe, Cu, and Zn) in the bread samples was determined by comparison with NIST orchard leaf standard. The accuracy of the measurements ranged between ±2% and ±10% for the most elements detected in this method. The aim of this study is to establish the reference concentration of trace elements in the Iraqi bread using PIXE technique. (author)

Filterless pre-concentration by co-precipitation by formation of crystalline precipitate in the analysis of barium by FIA-FAES

DEFF Research Database (Denmark)

Plamboeck, C.; Westtoft, H.C.; Pedersen, S.A.

2003-01-01

A novel method based on flow injection analysis (FIA) and flame atomic emission spectrometry (FAES) is presented. It was developed for direct determination of barium in drinking water, in natural water, in digested samples of bone and liver, in saline water and in a standard reference material...... (NIST SRM 1640). It was found that digestion of bone by an incineration procedure was required, in order to extract most of the barium. In the FIA manifold, barium was pre-concentrated by co-precipitation with lead chromate leading to a crystalline deposit that adhered well to the inner walls of a nylon...

Trace element determination in human bones using the neutron activation analysis method; Determinacao de elementos traco em ossos humanos pelo metodo de analise por ativacao com neutrons

Energy Technology Data Exchange (ETDEWEB)

Kramarski, Sila; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Borelli, Aurelio [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Lab. de Nutricao Humana; Batalha, Joao R.F. [Universidade de Mogi das Cruzes, SP (Brazil). Faculdade de Medicina

1997-10-01

This work presents the results obtained in the analysis of rib bone samples from normal human individuals by applying instrumental neutron activation analysis. In these analyses, the elements Br, Cl, Fe, K, Mg, Na, Rb, Sr and Zn were found at the ppm level and the elements Ca and P at the level of percentage. The precision and the of the results were evaluated by using biological reference materials NIST SRM 1577a Bovine Liver, IAEA A-11 Milk powder, NIES CRM 9 Sargasso e NIES CRM 10A Rice Flour Unpolished. (author). 5 refs., 3 tabs.

Trace element determination in human bones using the neutron activation analysis method

International Nuclear Information System (INIS)

Kramarski, Sila; Saiki, Mitiko; Borelli, Aurelio; Batalha, Joao R.F.

1997-01-01

This work presents the results obtained in the analysis of rib bone samples from normal human individuals by applying instrumental neutron activation analysis. In these analyses, the elements Br, Cl, Fe, K, Mg, Na, Rb, Sr and Zn were found at the ppm level and the elements Ca and P at the level of percentage. The precision and the of the results were evaluated by using biological reference materials NIST SRM 1577a Bovine Liver, IAEA A-11 Milk powder, NIES CRM 9 Sargasso e NIES CRM 10A Rice Flour Unpolished. (author). 5 refs., 3 tabs

CERT (registered trademark) Resilience Management Model (CERT (registered trademark)-RMM) V1.1: NIST Special Publication Crosswalk Version 2

Science.gov (United States)

2014-06-01

27000 series, COBIT, the British Standards Institution’s BS 25999, and ISO 24762  includes quantitative process measurements that can be used to...the NIST special publications 800 series, the International Organization for Standards ( ISO ) and International Electrotechnical Commission (IEC

A Preliminary Study of Elemental Characterization for Geochemical Markers of House and Cave Edible Bird's Nest Using NAA Technique

International Nuclear Information System (INIS)

Nazaratul Ashifa Abdullah Salim; Zainon Othman; Nor Afiqah Harun; Salmah Moosa; Siti Aminah Omar; Muhammad Azfar Azman; Md Suhaimi Elias; Shamsiah Abdul Rahman; Lim, C.C.

2016-01-01

Edible birds nest (EBN) is one the most highly valued food products of South East Asia. The nest is made by certain species of swift lets with a high protein glutinous secretion produced by their salivary glands. Malaysia is situated right at the heart of the golden triangle of swift let bird nest production, making it a strong producer in this lucrative agriculture industry. Issues facing the EBN industry include unknown source of origin with various quality grades, thus affecting export market and production subjected to fraud such as adulteration and counterfeiting. This study aims to characterize the elemental profiles as geochemical markers and evaluate the relationships between these markers which could be used for the verification of the geographical origin of EBN in Malaysia. EBN samples from house and cave nests that represent a range of geographical and environmental characteristics were analysed using Neutron Activation Analysis (NAA) technique. The method was validated by analysing the Standard Reference Material SRM-1515 (Apple Leaves) and SRM-1573a (Tomato Leaves) of NIST. A total of 15 elements were determined. The results showed significant different in elemental profile of EBN between the nest types on Al, As, Ba, Br, Ca, Cl, Na, Sc, Sm, Th and Rb content. (author)

EDXRF applied to the chemical characterization of domestic and industrial sludges

Energy Technology Data Exchange (ETDEWEB)

Silva, Gleyce Kelly A. da; Dutra, Emmanuel Damiliano, E-mail: gleyce_kelly990@hotmail.com, E-mail: emmanuel.dutra@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); França, Elvis J. de, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2017-07-01

The Energy Dispersion X-ray Fluorescence – EDXRF is a low-cost, fast, non-destructible analytical technique, useful for analyzing diverse geological samples. The determination of chemical elements by EDXRF in solid urban wastes is economic and operationally feasible, since the concentration of many heavy metals can be easily monitored. Besides, chemical elements as aluminum and some minerals that compose important natural cycles add valuable information for deciding the final destination of these wastes. The objective of this work was the obtaining the analytical curves for quantifying chemical elements by EDXRF in sewage sludge. For this, analytical portions (1 g) of the certified reference materials SRM 2781 Domestic Sludge and SRM 2782 Industrial Sludge produced by the National Institute of Standards and Technology (NIST) were transferred to polyethylene tubes and sealed at the top and bottom with polypropylene film specific for EDXRF analysis. Exactly 500 mg of each of the above SRMs were mixed by means of a ball mill for composing the SRM MIX, also analyzed for obtaining the analytical curves. All samples were analyzed in an atmosphere close to the vacuum (less than 30 Pa), with dead time less than 35%. For Al, As, Cu, Fe, K, Ni, Pb, Si, Ti and Zn, linear regressions have been fitted with respective linear coefficients higher than 0.95. To evaluate the quality of the analytical procedure, an independent test portion of the reference material SRM 2781 Sludge Domestic was used, calculating the Number En obtaining values between -1 and 1, range considered adequate for the quality assurance at the 95% confidence level. (author)

EDXRF applied to the chemical characterization of domestic and industrial sludges

International Nuclear Information System (INIS)

Silva, Gleyce Kelly A. da; Dutra, Emmanuel Damiliano; França, Elvis J. de

2017-01-01

The Energy Dispersion X-ray Fluorescence – EDXRF is a low-cost, fast, non-destructible analytical technique, useful for analyzing diverse geological samples. The determination of chemical elements by EDXRF in solid urban wastes is economic and operationally feasible, since the concentration of many heavy metals can be easily monitored. Besides, chemical elements as aluminum and some minerals that compose important natural cycles add valuable information for deciding the final destination of these wastes. The objective of this work was the obtaining the analytical curves for quantifying chemical elements by EDXRF in sewage sludge. For this, analytical portions (1 g) of the certified reference materials SRM 2781 Domestic Sludge and SRM 2782 Industrial Sludge produced by the National Institute of Standards and Technology (NIST) were transferred to polyethylene tubes and sealed at the top and bottom with polypropylene film specific for EDXRF analysis. Exactly 500 mg of each of the above SRMs were mixed by means of a ball mill for composing the SRM MIX, also analyzed for obtaining the analytical curves. All samples were analyzed in an atmosphere close to the vacuum (less than 30 Pa), with dead time less than 35%. For Al, As, Cu, Fe, K, Ni, Pb, Si, Ti and Zn, linear regressions have been fitted with respective linear coefficients higher than 0.95. To evaluate the quality of the analytical procedure, an independent test portion of the reference material SRM 2781 Sludge Domestic was used, calculating the Number En obtaining values between -1 and 1, range considered adequate for the quality assurance at the 95% confidence level. (author)

Neutron activation analysis of NBS oyster tissue (SRM 1566) and IAEA animal bone (H-5)

International Nuclear Information System (INIS)

Lepel, E.A.; Laul, J.C.

1983-10-01

Data have been presented for 35 elements determined by INAA for NBS oyster tissue (SRM 1566) and for 38 elements determined by INAA and RNAA for IAEA animal bone (H-5). The experimental data showed excellent agreement with published values wherever the comparison exists. Additional trace-element data in the ppb range have been presented for the elements Sc, Sb, Cs, La, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Yb, Lu, Hf, Ta, W and Th in NBS oyster tissue. Also, additional trace-element data for IAEA animal bone (H-5) in the ppb range for the elements Al, Sc, Co, Rb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, lu, Hf, Ta and Th have been presented

Liquid scintillation counting standardization of 125I in organic and inorganic samples by the CIEMAT/NIST method; Calibracion por centelleo liquido del 125I en muestras inorganicas y organicas, mediante el metodo CIEMAT/NIST

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J. M.; Grau Carles, A.

1994-07-01

The liquid scintillation counting standardization of organic and inorganic samples of ''I25I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%. (Author) 14 refs.

Application of neutron activation analysis for the determination of essential elements in egg samples; Aplicacao da analise por ativacao com neutrons para a determinacao de elementos essenciais em amostras de ovos

Energy Technology Data Exchange (ETDEWEB)

Gomes, Bruna G.; Maihara, Vera A.; Avegliano, Roseane P., E-mail: brunagabrielegomes@gmail.com, E-mail: vmaihara@ipen.br, E-mail: pagliaro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

The eggs are among the twenty foods consumed by the population of the five major regions of Brazil. Among the types of eggs, there are differences in nutritional value, which can vary according to the food of the bird. This study evaluating the elements Cl, K, Mg, Mn and Na considered essential micronutrients in food, because they are fundamental in several metabolic processes necessary for the maintenance and training of the human body. We analyzed three types of eggs: egg whites, of the quail, and the colonial in cooked and raw form, using the Instrumental Neutron Activation Analysis method (INAA). The egg samples were lyophilized and pulverized before analysis. To validate the methodology, reference materials NIST RM 8415 Whole Egg Powder and NIST SRM 1567 Wheat Flour were analyzed. The samples, reference materials and standards of the elements were irradiated for 20 seconds under a thermal neutron flux of 6,6x10{sup 12} cm -2 s -1 in the nuclear research reactor IEA-R1 of IPEN-CNEN / SP. The results were consistent with the values of the Brazilian Table of Food Composition (TACO)

Preparation and LSC standardization of ''89 Sr (DNP) using the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Arcos Merino, J.M. Los; Grau Malonda, A.

1994-01-01

A procedure for preparation of liquid scintillation counting samples of the strontium DNP complex, labelled with ''89 Sr, is described. The chemical quench, the counting stability and spectral evolution of this compound is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-naphthalene, HiSafe II, Ultima-Gold and Instagel. The liquid scintillation standardization of ''89Sr-DNP by the CIEMAT/NIST method, using Hisafe II and Ultima-Gold scintillators, has been carried out. The discrepancies between experimental and computed efficiencies are lower than 0.38% and 0.48%, respectively. The solution has been standardized in terms of activity concentration to an overall uncertainty of 0.38%. (Author)

Update of NIST half-life results corrected for ionization chamber source-holder instability.

Science.gov (United States)

Unterweger, M P; Fitzgerald, R

2014-05-01

As reported at the ICRM 2011, it was discovered that the source holder used for calibrations in the NIST 4πγ ionization chamber (IC) was not stable. This has affected a large number of half-life measurement results previously reported and used in compilations of nuclear data. Corrections have been made on all of the half-life data based on the assumption that the changes to the ionization chamber response were gradual. The corrections are energy dependent and therefore radionuclide specific. This presentation will review our results and present the recommended changes in half-life values and/or uncertainties. © 2013 Published by Elsevier Ltd.

Preparation and LSC Standardization of ''89Sr (DNP) Using the CIEMAT/NIST Method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Los Arcos Merino, J. M.; Grau Malonda, A.

1994-01-01

A procedure for preparation of liquid scintillation counting samples of the strontium DNP complex, labelled with ''89Sr, is described, the chemical quench, the counting stability and spectral evolution of this compound is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-naphthalene, HiSafe II, Ultima- Gold and Instagel. The liquid scintillation standardization of 89Sr-DNP by the CIEMAT/NIST method, using HiSafe II and Ultima-Gold scintillators, has been carried out. The discrepancies between experimental and computed efficiencies are lower than 0.38% and 0.48%, respectively. The solution has been standardized in terms of activity concentration to an overall uncertainty of 0,38%. (Author) 10 refs

Simulation evaluation of NIST air-kerma rate calibration standard for electronic brachytherapy.

Science.gov (United States)

Hiatt, Jessica R; Rivard, Mark J; Hughes, H Grady

2016-03-01

Dosimetry for the model S700 50 kV electronic brachytherapy (eBT) source (Xoft, Inc., a subsidiary of iCAD, San Jose, CA) was simulated using Monte Carlo (MC) methods by Rivard et al. ["Calculated and measured brachytherapy dosimetry parameters in water for the Xoft Axxent x-ray source: An electronic brachytherapy source," Med. Phys. 33, 4020-4032 (2006)] and recently by Hiatt et al. ["A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model," Med. Phys. 42, 2764-2776 (2015)] with improved geometric characterization. While these studies examined the dose distribution in water, there have not previously been reports of the eBT source calibration methods beyond that recently reported by Seltzer et al. ["New national air-kerma standard for low-energy electronic brachytherapy sources," J. Res. Natl. Inst. Stand. Technol. 119, 554-574 (2014)]. Therefore, the motivation for the current study was to provide an independent determination of air-kerma rate at 50 cm in air K̇air(d=50 cm) using MC methods for the model S700 eBT source. Using CAD information provided by the vendor and disassembled sources, an MC model was created for the S700 eBT source. Simulations were run using the mcnp6 radiation transport code for the NIST Lamperti air ionization chamber according to specifications by Boutillon et al. ["Comparison of exposure standards in the 10-50 kV x-ray region," Metrologia 5, 1-11 (1969)], in air without the Lamperti chamber, and in vacuum without the Lamperti chamber. K̇air(d=50 cm) was determined using the *F4 tally with NIST values for the mass energy-absorption coefficients for air. Photon spectra were evaluated over 2 π azimuthal sampling for polar angles of 0° ≤ θ ≤ 180° every 1°. Volume averaging was averted through tight radial binning. Photon energy spectra were determined over all polar angles in both air and vacuum using

Optimization of fly ash as sand replacement materials (SRM) in cement composites containing coconut fiber

Science.gov (United States)

Nadzri, N. I. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

2016-07-01

The need of utilizing industrial and agricultural wastes is very important to maintain sustainability. These wastes are often incorporated with cement composites to improve performances in term of physical and mechanical properties. This study presents the results of the investigation of the response of cement composites containing coconut fiber as reinforcement and fly ash use as substitution of sand at different hardening days. Hardening periods of time (7, 14 and 28 days) were selected to study the properties of cement composites. Optimization result showed that 20 wt. % of fly ash (FA) is a suitable material for sand replacement (SRM). Meanwhile 14 days of hardening period gave highest compressive strength (70.12 MPa) from the cement composite containing 9 wt. % of coconut fiber and fly ash. This strength was comparable with the cement without coconut fiber (74.19 MPa) after 28 days of curing.

Specific radiological monitoring (SRM) in oil and gas production platforms

International Nuclear Information System (INIS)

Hairul Nizam Idris, Syed Asraf Fahlawi Wafa S.M Ghazi and Fadzley Izwan Abd Manaf

2007-01-01

Technologically enhanced naturally occurring radioactive materials (TENORM) are present in components of both oil and natural gas production facilities. TENORM can be associated with the presence of crude oil, produced water and natural gas. The radiation exposure pathways to the workers in oil and gas production are similar to those in the uranium and heavy mineral sand mining and processing industry. This paper work provides a short review on the Specific Radiological Monitoring (SRM) program were carried out at oil and gas platforms in the east cost of Peninsular Malaysia. The objective of this paper work is to observe the monitoring parameters levels and to evaluate whether these levels are exceeding the limits set by Atomic Energy Licensing Board (AELB). The monitoring results showed that the surface contamination, airborne contamination and concentration of radon and thoron are well below the set limit stipulated in LEM/TEK/30 SEM.2, except for external radiation and radioactivity concentration of sludge and scales. About 2 (2.35%) from the 85 external radiation measurements performed were found above the permissible limit. While about 11 (36.6%) and 7 (23.3%) of the 30 collected sludge and scales samples were found containing higher Ra-226 and Ra-228, respectively, than the mean concentrations in normal soils of Peninsular Malaysia. In general, it can be concluded that a few of oil and gas production platform are producing TENORM. (Author)

Applications of surface metrology in firearm identification

International Nuclear Information System (INIS)

Zheng, X; Soons, J; Vorburger, T V; Song, J; Renegar, T; Thompson, R

2014-01-01

Surface metrology is commonly used to characterize functional engineering surfaces. The technologies developed offer opportunities to improve forensic toolmark identification. Toolmarks are created when a hard surface, the tool, comes into contact with a softer surface and causes plastic deformation. Toolmarks are commonly found on fired bullets and cartridge cases. Trained firearms examiners use these toolmarks to link an evidence bullet or cartridge case to a specific firearm, which can lead to a criminal conviction. Currently, identification is typically based on qualitative visual comparison by a trained examiner using a comparison microscope. In 2009, a report by the National Academies called this method into question. Amongst other issues, they questioned the objectivity of visual toolmark identification by firearms examiners. The National Academies recommended the development of objective toolmark identification criteria and confidence limits. The National Institute of Standards and Technology (NIST) have applied its experience in surface metrology to develop objective identification criteria, measurement methods, and reference artefacts for toolmark identification. NIST developed the Standard Reference Material SRM 2460 standard bullet and SRM 2461 standard cartridge case to facilitate quality control and traceability of identifications performed in crime laboratories. Objectivity is improved through measurement of surface topography and application of unambiguous surface similarity metrics, such as the maximum value (ACCF MAX ) of the areal cross correlation function. Case studies were performed on consecutively manufactured tools, such as gun barrels and breech faces, to demonstrate that, even in this worst case scenario, all the tested tools imparted unique surface topographies that were identifiable. These studies provide scientific support for toolmark evidence admissibility in criminal court cases. (paper)

JY1 time scale: a new Kalman-filter time scale designed at NIST

International Nuclear Information System (INIS)

Yao, Jian; Parker, Thomas E; Levine, Judah

2017-01-01

We report on a new Kalman-filter hydrogen-maser time scale (i.e. JY1 time scale) designed at the National Institute of Standards and Technology (NIST). The JY1 time scale is composed of a few hydrogen masers and a commercial Cs clock. The Cs clock is used as a reference clock to ease operations with existing data. Unlike other time scales, the JY1 time scale uses three basic time-scale equations, instead of only one equation. Also, this time scale can detect a clock error (i.e. time error, frequency error, or frequency drift error) automatically. These features make the JY1 time scale stiff and less likely to be affected by an abnormal clock. Tests show that the JY1 time scale deviates from the UTC by less than  ±5 ns for ∼100 d, when the time scale is initially aligned to the UTC and then is completely free running. Once the time scale is steered to a Cs fountain, it can maintain the time with little error even if the Cs fountain stops working for tens of days. This can be helpful when we do not have a continuously operated fountain or when the continuously operated fountain accidentally stops, or when optical clocks run occasionally. (paper)

Comparison of inductively coupled plasma mass spectrometry with inductively coupled plasma atomic emission spectrometry and instrumental neutron activation analysis for the determination of rare earth elements in Greek bauxites

International Nuclear Information System (INIS)

Ochsenkuehn-Petropoulou, Maria; Luck, Joachim

1991-01-01

Fore the determination of rare earth elements (REE) in bauxitic materials the techniques of inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and instrumental neutron activation analysis (INAA) were compared. In the NIST (National Institute of Standards and Technology) bauxites SRM 697 Dominican, and SRM 69 b Arkansas, the concentration of some REEs were determined. With the reference bauxite BX-N of the ARNT (Association Nationale de la Recherche Technique) the precision and accuracy of ICP-AES for the determination of REEs in bauxites was tested. Furthermore, Greek bauxites of the Parnassos-Giona area were investigated. In a comparison of the three methods it was possible to calculate from the data series the precision of each method, which showed that the tendency found in the deviations for the different REEs is in accordance with published values. Also the limits of detection for REEs in bauxites were calculated and found to be in the same range as those in the literature. (author)

Sonication assisted dissolution of post-detonation nuclear debris using ammonium bifluoride

Energy Technology Data Exchange (ETDEWEB)

Mason, Christian A.; Brockman, John D. [Missouri Univ., Columbia, MO (United States). Research Reactor Center; Hubley, Nicholas T.; Wegge, Dana L. [Missouri Univ., Columbia, MO (United States). Dept. of Chemistry; Robertson, J. David [Missouri Univ., Columbia, MO (United States). Research Reactor Center; Missouri Univ., Columbia, MO (United States). Dept. of Chemistry

2017-07-01

There is significant interest in reducing the timeline for post detonation nuclear debris examination. A critical need is rapid dissolution of refractory nuclear debris to facilitate measurement of key radioisotopes and isotope ratios. Field deployable, rapid dissolution and analysis methods could significantly shorten the attribution analysis timeline. The current practice uses HF in combination with other acids to attack silicates and other refractory minerals expected in debris samples. However, techniques requiring HF are not amenable to use in the field. The fluorinating agent ammonium bifluoride (ABF) is a potential field deployable substitute for HF. In this work we report on the use of in-direct sonication with ABF as a means to improve low-temperature acid digestion of seven USGS and NIST geological reference materials. Using this method, elemental recoveries for USGS reference materials DNC-1a Dolerite, QLO-1a Quartz Latite, SDC-1 Mica Schist, and BHVO-2 Hawaiian Basalt were quantitative while the recovery of elements in USGS AGV-2 Andesite and NIST SRM 278 Obsidian and 1413 High Alumina Sand were low.

2D elemental mapping of sections of human kidney stones using laser ablation inductively-coupled plasma-mass spectrometry: Possibilities and limitations

Energy Technology Data Exchange (ETDEWEB)

Vašinová Galiová, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Čopjaková, Renata; Škoda, Radek [Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Štěpánková, Kateřina; Vaňková, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kuta, Jan [Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Prokeš, Lubomír [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kynický, Jindřich [Department of Pedology and Geology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno (Czech Republic); and others

2014-10-01

A 213 nm Nd:YAG-based laser ablation (LA) system coupled to quadrupole-based inductively coupled plasma-mass spectrometer and an ArF* excimer-based LA-system coupled to a double-focusing sector field inductively coupled plasma-mass spectrometer were employed to study the spatial distribution of various elements in kidney stones (uroliths). Sections of the surfaces of uroliths were ablated according to line patterns to investigate the elemental profiles for the different urolith growth zones. This exploratory study was mainly focused on the distinguishing of the main constituents of urinary calculus fragments by means of LA-ICP-mass spectrometry. Changes in the ablation rate for oxalate and phosphate phases related to matrix density and hardness are discussed. Elemental association was investigated on the basis of 2D mapping. The possibility of using NIST SRM 1486 Bone Meal as an external standard for calibration was tested. It is shown that LA-ICP-MS is helpful for determination of the mineralogical composition and size of all phases within the analyzed surface area, for tracing down elemental associations and for documenting the elemental content of urinary stones. LA-ICP-MS results (elemental contents and maps) are compared to those obtained with electron microprobe analysis and solution analysis ICP-MS. - Highlights: • Elements in phosphate and oxalate urolith phases were quantified by LA-ICP-MS. • SRM NIST 1486 Bone Meal was proved suitable for quantification in uroliths. • Different ablation rates in particular phases were included at quantification. • Oxalate and apatite phases show opposite hardness order to natural minerals. • Uroliths were classified according to elemental association to phases.

Determination of rare earth elements by liquid chromatographic separation using inductively coupled plasma mass spectrometric detection

International Nuclear Information System (INIS)

Braverman, D.S.

1992-01-01

High-performance liquid chromatography (HPLC) is used to separate the rare earth elements (REEs) prior to detection by inductively coupled plasma mass spectrometry (ICP-MS). The use of HPLC-ICP-MS in series combines the separation power and speed of HPLC with the sensitivity, isotopic selectivity and speed of ICP-MS. The detection limits for the REEs are in the sub-ng ml -1 range and the response is linear over four orders of magnitude. A preliminary comparison of isotope dilution and external standard results for the determination of REEs in National Institute of Standards and Technology (NIST) Standard Reference Material (SRM 1633a) Fly Ash is presented. (author)

Precise determination of δ88Sr in rocks, minerals, and waters by double-spike TIMS: A powerful tool in the study of chemical, geologic, hydrologic and biologic processes

Science.gov (United States)

Neymark, Leonid A.; Premo, Wayne R.; Mel'nikov, Nikolay N.; Emsbo, Poul

2014-01-01

We present strontium isotopic (88Sr/86Sr and 87Sr/86Sr) results obtained by 87Sr–84Sr double spike thermal ionization mass-spectrometry (DS-TIMS) for several standards as well as natural water samples and mineral samples of abiogenic and biogenic origin. The detailed data reduction algorithm and a user-friendly Sr-specific stand-alone computer program used for the spike calibration and the data reduction are also presented. Accuracy and precision of our δ88Sr measurements, calculated as permil (‰) deviations from the NIST SRM-987 standard, were evaluated by analyzing the NASS-6 seawater standard, which yielded δ88Sr = 0.378 ± 0.009‰. The first DS-TIMS data for the NIST SRM-607 potassium feldspar standard and for several US Geological Survey carbonate, phosphate, and silicate standards (EN-1, MAPS-4, MAPS-5, G-3, BCR-2, and BHVO-2) are also reported. Data obtained during this work for Sr-bearing solids and natural waters show a range of δ88Sr values of about 2.4‰, the widest observed so far in terrestrial materials. This range is easily resolvable analytically because the demonstrated external error (±SD, standard deviation) for measured δ88Sr values is typically ≤0.02‰. It is shown that the “true” 87Sr/86Sr value obtained by the DS-TIMS or any other external normalization method combines radiogenic and mass-dependent mass-fractionation effects, which cannot be separated. Therefore, the “true” 87Sr/86Sr and the δ87Sr parameter derived from it are not useful isotope tracers. Data presented in this paper for a wide range of naturally occurring sample types demonstrate the potential of the δ88Sr isotope tracer in combination with the traditional radiogenic 87Sr/86Sr tracer for studying a variety of biological, hydrological, and geological processes.

Pinus roxburghii plant needles as a three-season biomonitor for elemental air pollution monitoring along roadside

Energy Technology Data Exchange (ETDEWEB)

Daud, Muhammad; Wasim, Mohammad; Khalid, Nasir; Waheed, Shahida [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

2015-07-01

The present study deals with the determination of 36 elements in Pinus roxburghii plant needles to assess their potential as biomonitor for elemental air pollution monitoring. The elemental quantification was made by employing Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometric (AAS) techniques. The needles of Pinus roxburghii were collected in spring, summer and winter seasons from various sites in Islamabad. The method validation was performed by analyzing two certified reference materials i.e., Citrus leaves - NIST-SRM-1572 and IAEA-Soil-7. Pollution level was assessed by using three indicators: enrichment factor, pollution load index and average toxic element concentration. The results indicated that the needles of Pinus roxburghii plant had potential to monitor the extent of air pollution in the vicinity of high traffic areas.

Determinação simultânea de As, Cd e Pb em amostras de água purificada para hemodiálise por espectrometria de absorção atômica com forno de grafite, após otimização multivariada baseada no uso de planejamento experimental Simultaneous determination of arsenic, cadmium and lead by GF AAS in purified water samples for hemodialysis after multivariate optimization based on factorial design

Directory of Open Access Journals (Sweden)

Lisia Maria G. dos Santos

2008-01-01

Full Text Available This paper reports the development of a methodology for simultaneously determining As, Cd and Pb, employing GF AAS with polarized Zeeman-effect background correction. In order to make the procedure applicable, the influence of pyrolysis and atomization temperatures and the amount of chemical modifiers were studied. Factorial and central composite designs were used to optimize these variables. Precision and accuracy of the method were investigated using Natural Water Reference material, Nist SRM 1640. Results are in agreement with certified values at the 95% confidence limit when the Student t-test is used. This methodology was used for quality control of purified water for hemodialysis.

Preparation and LSC Standardization of ''89Sr (DNP) Using the CIEMAT/NIST Method; Preparacion del ''89Sr(DNP) y calibracion por centelleo liquido, mediante el metodo CIEMAT/NIST

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Barquero, L.; Los Arcos Merino, J. M.; Grau Malonda, A.

1994-07-01

A procedure for preparation of liquid scintillation counting samples of the strontium DNP complex, labelled with ''89Sr, is described, the chemical quench, the counting stability and spectral evolution of this compound is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-naphthalene, HiSafe II, Ultima- Gold and Instagel. The liquid scintillation standardization of 89Sr-DNP by the CIEMAT/NIST method, using HiSafe II and Ultima-Gold scintillators, has been carried out. The discrepancies between experimental and computed efficiencies are lower than 0.38% and 0.48%, respectively. The solution has been standardized in terms of activity concentration to an overall uncertainty of 0,38%. (Author) 10 refs.

Liquid scintillation counting standardization of ''125 I in organic and inorganic samples by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J.M.; Grau Carles, A.

1994-01-01

The liquid scintillation counting standardization of organic and inorganic samples of ''125 I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%

Validation of an analytical method for the determination of the sodium content in foods

International Nuclear Information System (INIS)

Valverde Montero, Ericka; Silva Trejos, Paulina

2012-01-01

The analytical methodology for quantitative determination of sodium in foods by flame atomic absorption spectrometry was validated. The samples of 0,5 g was realized by microwave oven with 5,0 mL of nitric acid (HNO 3 ) to 65% by mass. The linearity range has been from 0,043 mg/L to 0,70 mg/L with a correlation coefficient equal to 0,998. The detection and quantification limits have reported 0,025 mg/L and 0,043 mg/L, respectively; with 0,805 Lmg -1 of calibration sensitivity and 44 Lmg -1 of analytical sensitivity. The precision was evaluated in terms of repeatability and have obtained a value equal to 2,9% RDS r . The trueness was determined using three NIST ® , certified standards SRM 1846 Infant Formula with a reported value for sodium of (2310 ± 130) mg/kg, SRM 8414 Bovine Muscle Powder with a reported value for sodium of (0,210 ± 0,008)% and SRM 8415 Whole Egg Powder with a reported value for sodium of (0,377 ± 0,034)% by mass. The bias have obtained an average between(-0,010 to 0,009) mg/L. From the list of foods that were selected for the study, for example, whole milk powder, white wheat bread, fresh cheese and mozzarella cheese have submitted highest content in sodium concentrations, ranging from (106 to 452) mg Na /100g. (author) [es

Analysis of soils by glow discharge mass spectrometry

International Nuclear Information System (INIS)

Duckworth, D.C.; Barshick, C.M.; Smith, D.H.

1993-01-01

The analysis of soils by conventional solution-based techniques, such as inductively coupled plasma and thermal ionization mass spectrometry, is complicated by the need for sample dissolution or the combination of a solids atomizer with an auxiliary ionization source. Since time is an important consideration in waste remediation, there exists a need for a method of rapidly analysing many soil samples with little sample preparation; glow discharge mass spectrometry (GDMS) has the potential to meet this need. Because GDMS is a bulk solids technique, sample preparation is simplified in comparison to other methods. Even with the most difficult samples (geological materials, such as soils and volcanic rock), all that is required is grinding, drying and mixing with a conducting host material prior to electrode formation. As a first test of GDMS for soil analysis, a National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) was analysed by direct current GDMS. Fifty-one elements were quantified from a single cathode using ion beam ratios and ''standard'' relative elemental sensitivity factors (RSF). Average errors for the suite of elements were less than a factor of 4 and 1.4 for uncorrected and corrected values, respectively. User-generated RSF values were applied to the analysis of several elements in NIST SRM 2704 Buffalo River Sediment. In the absence of isobaric interferences, accuracies ranging from 0.6 to 73% were observed, demonstrating the potential of the technique for the determination of many elements. The presence of entrained water and inhomogeneity resulting from cathode preparation is thought to affect matrix-to-matrix reproducibility. While further success depends on developing means of circumventing mass spectral interferences and addressing factors affecting plasma chemistry, the immediate goal of developing a screening method for priority metals in soils was met. (Author)

Liquid scintillation counting standardization of 125I in organic and inorganic samples by the CIEMAT/NIST method

International Nuclear Information System (INIS)

Rodriguez Barquero, L.; Grau Malonda, A.; Los Arcos Merino, J. M.; Grau Carles, A.

1994-01-01

The liquid scintillation counting standardization of organic and inorganic samples of ''I25I by the CIEMAT/NIST method using five different scintillators is described. The discrepancies between experimental and computed efficiencies are lower than 1.4% and 1.7%, for inorganic and organic samples, respectively, in the interval 421-226 of quenching parameter. Both organic and inorganic solutions have been standardized in terms of activity concentration to an overall uncertainty of 0.76%. (Author) 14 refs

Activity measurements of the radionuclide 109Cd for the PTB, Germany and the NIST, USA in the ongoing comparison BIPM.RI(II)-K1.Cd-109

International Nuclear Information System (INIS)

Ratel, G.; Michotte, C.; Janssen, H.; Kossert, K.; Lucas, L.; Karam, L.

2005-01-01

In 2004, the Physikalisch-Technische Bundesanstalt (PTB, Germany) and the National Institute of Standards and Technology (NIST, USA) each submitted one sample of known activity of 109 Cd to the International Reference System (SIR). The PTB result replaces their previous measurement of 1994 and the NIST result updates their 1986 CCRI(II) comparison result. The values of the activity submitted were about 15 MBq and 42 MBq. The new key comparison results have replaced the earlier values in the matrix of degrees of equivalence that now contains six results, identifier BIPM.RI(II)-K1.Cd-109, to which the remaining eleven results from the CCRI(II)-K2.Cd-109 held in 1986 are still linked. (authors)

EDXRF applied to the chemical element determination of small invertebrate samples

International Nuclear Information System (INIS)

Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de

2015-01-01

Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E n Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

Development of an on-line flow injection Sr/matrix separation method for accurate, high-throughput determination of Sr isotope ratios by multiple collector-inductively coupled plasma-mass spectrometry.

Science.gov (United States)

Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas

2007-07-01

This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.

Use of the HRICP-MS technique for the evaluation of boron isotopes in Eucalitpus plants

International Nuclear Information System (INIS)

Mattiello, Edson Marcio; Ruiz, Hugo Alberto; Silva, Ivo Ribeiro da

2011-01-01

The 10 B isotope tracer technique is essential to study the B mobility in plants. Factors that can influence the quality of measured B isotope ratios were optimized experimentally using High Resolution Inductively Coupled Plasma Mass Spectrometry (HRICP-MS). An isotopically certified standard (NIST SRM-951) was used. The best combination was obtained using a resolution of 400, a RF power of 1250 W, followed by 15 measurements over a 10-s integration period each (15*10). Utilizing this approach it was possible to obtain a precision of 0.3 % in standard material and 2z % in the experimental samples. The results show the importance of establishing optimized work conditions before carrying out the analytical series. (author)

Use of the HRICP-MS technique for the evaluation of boron isotopes in Eucalitpus plants; Uso da tecnica HRICP-MS na avaliacao dos isotopos de boro em eucalipto

Energy Technology Data Exchange (ETDEWEB)

Mattiello, Edson Marcio; Ruiz, Hugo Alberto; Silva, Ivo Ribeiro da, E-mail: mattiello@ufv.b [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Solos; Sarkis, Jorge Eduardo de Souza [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The {sup 10}B isotope tracer technique is essential to study the B mobility in plants. Factors that can influence the quality of measured B isotope ratios were optimized experimentally using High Resolution Inductively Coupled Plasma Mass Spectrometry (HRICP-MS). An isotopically certified standard (NIST SRM-951) was used. The best combination was obtained using a resolution of 400, a RF power of 1250 W, followed by 15 measurements over a 10-s integration period each (15*10). Utilizing this approach it was possible to obtain a precision of 0.3 % in standard material and 2z % in the experimental samples. The results show the importance of establishing optimized work conditions before carrying out the analytical series. (author)

Evaluation of bilirubin interference and accuracy of six creatinine assays compared with isotope dilution-liquid chromatography mass spectrometry.

Science.gov (United States)

Nah, Hyunjin; Lee, Sang-Guk; Lee, Kyeong-Seob; Won, Jae-Hee; Kim, Hyun Ok; Kim, Jeong-Ho

2016-02-01

The aim of this study was to estimate bilirubin interference and accuracy of six routine methods for measuring creatinine compared with isotope dilution-liquid chromatography mass spectrometry (ID-LC/MS). A total of 40 clinical serum samples from 31 patients with serum total bilirubin concentration >68.4μmol/L were collected. Serum creatinine was measured using two enzymatic reagents and four Jaffe reagents as well as ID-LC/MS. Correlations between bilirubin concentration and percent difference in creatinine compared with ID-LC/MS were analyzed to investigate bilirubin interference. Bias estimations between the six reagents and ID-LC/MS were performed. Recovery tests using National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 967a were also performed. Both the enzymatic methods showed no bilirubin interference. However, three of the four Jaffe methods demonstrated significant bilirubin concentration-dependent interference in samples with creatinine levels creatinine levels ranging from 53.0 to 97.2μmol/L. Comparison of these methods with ID-LC/MS using patients' samples with elevated bilirubin revealed that the tested methods failed to achieve the bias goal at especially low levels of creatinine. In addition, recovery test using NIST SRM 967a showed that bias in one Jaffe method and two enzymatic methods did not achieve the bias goal at either low or high level of creatinine, indicating they had calibration bias. One enzymatic method failed to achieve all the bias goals in both comparison experiment and recovery test. It is important to understand that both bilirubin interference and calibration traceability to ID-LC/MS should be considered to improve the accuracy of creatinine measurement. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Findings and Recommendations from the NIST Workshop on Alternative Fuels and Materials: Biocorrosion.

Science.gov (United States)

Mansfield, Elisabeth; Sowards, Jeffrey W; Crookes-Goodson, Wendy J

2015-01-01

In 2013, the Applied Chemicals and Materials Division of the National Institute of Standards and Technology (NIST) hosted a workshop to identify and prioritize research needs in the area of biocorrosion. Materials used to store and distribute alternative fuels have experienced an increase in corrosion due to the unique conditions caused by the presence of microbes and the chemistry of biofuels and biofuel precursors. Participants in this workshop, including experts from the microbiological, fuel, and materials communities, delved into the unique materials and chemical challenges that occur with production, transport, and storage of alternative fuels. Discussions focused on specific problems including: a) the changing composition of "drop-in" fuels and the impact of that composition on materials; b) the influence of microbial populations on corrosion and fuel quality; and c) state-of-the-art measurement technologies for monitoring material degradation and biofilm formation.

High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

Science.gov (United States)

Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

1987-01-01

Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

Selenium determination in cereal plants and cultivation soils by radiochemical neutron activation analysis

International Nuclear Information System (INIS)

Galinha, C.; Freitas, M.C.; Anawar, H.M.; Pacheco, A.M.G.; Kamenik, J.; Kucera, J.; Coutinho, J.; Macas, B.; Almeida, A.S.

2012-01-01

Selenium (Se) is an essential micronutrient for human health but it is deficient in at least 1 billion people around the globe. Cereals are by far the most significant agricultural crops, not only on a gross tonnage basis, but also by what they represent in terms of energy supply and dietary intake for human nutrition worldwide. Portugal is no exception to such pattern. The Portuguese situation is difficult to assess though, due to scarce information and lack of consistent studies on the subject. In these terms, the Se status of major cereals and their cultivation soils are dealt with herein. Two species of wheat-bread and durum wheat-were sown at the end of November 2009, and then sampled in different growth stages. Rye was collected during harvest season, and cultivation soils were analyzed as well. Se results were within the range of: 100-225 ng g -1 for soils; 3-55 ng g -1 for durum wheat; 6-80 ng g -1 for bread wheat; and 4-30 ng g -1 for rye. Accuracy of the RNAA procedure was proved by analysis of reference materials NIST-SRM 1515 and NIS-SRM 8433. (author)

A novel sample preparation method using rapid nonheated saponification method for the determination of cholesterol in emulsified foods.

Science.gov (United States)

Jeong, In-Seek; Kwak, Byung-Man; Ahn, Jang-Hyuk; Leem, Donggil; Yoon, Taehyung; Yoon, Changyong; Jeong, Jayoung; Park, Jung-Min; Kim, Jin-Man

2012-10-01

In this study, nonheated saponification was employed as a novel, rapid, and easy sample preparation method for the determination of cholesterol in emulsified foods. Cholesterol content was analyzed using gas chromatography with a flame ionization detector (GC-FID). The cholesterol extraction method was optimized for maximum recovery from baby food and infant formula. Under these conditions, the optimum extraction solvent was 10 mL ethyl ether per 1 to 2 g sample, and the saponification solution was 0.2 mL KOH in methanol. The cholesterol content in the products was determined to be within the certified range of certified reference materials (CRMs), NIST SRM 1544 and SRM 1849. The results of the recovery test performed using spiked materials were in the range of 98.24% to 99.45% with an relative standard devitation (RSD) between 0.83% and 1.61%. This method could be used to reduce sample pretreatment time and is expected to provide an accurate determination of cholesterol in emulsified food matrices such as infant formula and baby food. A novel, rapid, and easy sample preparation method using nonheated saponification was developed for cholesterol detection in emulsified foods. Recovery tests of CRMs were satisfactory, and the recoveries of spiked materials were accurate and precise. This method was effective and decreased the time required for analysis by 5-fold compared to the official method. © 2012 Institute of Food Technologists®

Application of neutron activation analysis for the determination of essential elements in egg samples

International Nuclear Information System (INIS)

Gomes, Bruna G.; Maihara, Vera A.; Avegliano, Roseane P.

2013-01-01

The eggs are among the twenty foods consumed by the population of the five major regions of Brazil. Among the types of eggs, there are differences in nutritional value, which can vary according to the food of the bird. This study evaluating the elements Cl, K, Mg, Mn and Na considered essential micronutrients in food, because they are fundamental in several metabolic processes necessary for the maintenance and training of the human body. We analyzed three types of eggs: egg whites, of the quail, and the colonial in cooked and raw form, using the Instrumental Neutron Activation Analysis method (INAA). The egg samples were lyophilized and pulverized before analysis. To validate the methodology, reference materials NIST RM 8415 Whole Egg Powder and NIST SRM 1567 Wheat Flour were analyzed. The samples, reference materials and standards of the elements were irradiated for 20 seconds under a thermal neutron flux of 6,6x10 12 cm -2 s -1 in the nuclear research reactor IEA-R1 of IPEN-CNEN / SP. The results were consistent with the values of the Brazilian Table of Food Composition (TACO)

Single-laboratory validation of a high-performance liquid chromatographic-diode array detector-fluorescence detector/mass spectrometric method for simultaneous determination of water-soluble vitamins in multivitamin dietary tablets.

Science.gov (United States)

Chen, Pei; Atkinson, Renata; Wolf, Wayne R

2009-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 microm, 250 x 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLDIMS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Primary standardization of C-14 by means of CIEMAT/NIST, TDCR and 4πβ-γ methods

International Nuclear Information System (INIS)

Kuznetsova, Maria

2016-01-01

In this work, the primary standardization of "1"4C solution, which emits beta particles of maximum energy 156 keV, was made by means of three different methods: CIEMAT/NIST and TDCR (Triple To Double Coincidence Ratio) methods in liquid scintillation systems and the tracing method, in the 4πβ-γ coincidence system. TRICARB LSC (Liquid Scintillator Counting) system, equipped with two photomultipliers tubes, was used for CIEMAT/NIST method, using a "3H standard that emits beta particles with maximum energy of 18.7 keV, as efficiency tracing. HIDEX 300SL LSC system, equipped with three photomultipliers tubes, was used for TDCR method. Samples of "1"4C and "3H, for the liquid scintillator system, were prepared using three commercial scintillation cocktails, UltimaGold, Optiphase Hisafe3 and InstaGel-Plus, in order to compare the performance in the measurements. All samples were prepared with 15 mL scintillators, in glass vials with low potassium concentration. Known aliquots of radioactive solution were dropped onto the cocktail scintillators. In order to obtain the quenching parameter curve, a nitro methane carrier solution and 1 mL of distilled water were used. For measurements in the 4πβ-γ system, "6"0Co was used as beta gamma emitter. SCS (software coincidence system) was applied and the beta efficiency was changed by using electronic discrimination. The behavior of the extrapolation curve was predicted with code ESQUEMA, using Monte Carlo technique. The "1"4C activity obtained by the three methods applied in this work was compared and the results showed to be in agreement, within the experimental uncertainty. (author)

A new method in estimation of total hexavalent chromium in Portland pozzolan cement

International Nuclear Information System (INIS)

Sharma, R.; Sharma, D.

2017-01-01

Variamine blue was used first time for the detection of hexavalent chromium from cement samples. In present method, cement was treated sequentially with water, sulphate and carbonate buffer to extract soluble, sparingly soluble and insoluble hexavalent chromium respectively. Extracted Cr (VI) was determined using variamine blue as chromogenic reagent. The determination is based on the reaction of hexavalent chromium with potassium iodide in an acid medium to liberate iodine. This oxidizes variamine blue to form a violet coloured species having an absorption to maximum at 556 nm. Energy-dispersive X-ray spectroscopy (EDX) and Infrared Spectroscopy (IR) confirmed the complete extraction of hexavalent chromium by sequential extraction process. SRM 2701 (Reference material from NIST, USA) was used for revalidating the results. The percentage of recovery for proposed and reference method (diphelycarbazide method) varied from 98.5 to 101 and 97.5 to 100.5. Whereas, their relative error percentage varied from -1.5 to 0.33 and -2.5 to 0.5. [es

Repeatability of magnetic resonance fingerprinting T1 and T2 estimates assessed using the ISMRM/NIST MRI system phantom.

Science.gov (United States)

Jiang, Yun; Ma, Dan; Keenan, Kathryn E; Stupic, Karl F; Gulani, Vikas; Griswold, Mark A

2017-10-01

The purpose of this study was to evaluate accuracy and repeatability of T 1 and T 2 estimates of a MR fingerprinting (MRF) method using the ISMRM/NIST MRI system phantom. The ISMRM/NIST MRI system phantom contains multiple compartments with standardized T 1 , T 2 , and proton density values. Conventional inversion-recovery spin echo and spin echo methods were used to characterize the T 1 and T 2 values in the phantom. The phantom was scanned using the MRF-FISP method over 34 consecutive days. The mean T 1 and T 2 values were compared with the values from the spin echo methods. The repeatability was characterized as the coefficient of variation of the measurements over 34 days. T 1 and T 2 values from MRF-FISP over 34 days showed a strong linear correlation with the measurements from the spin echo methods (R 2  = 0.999 for T 1 ; R 2  = 0.996 for T 2 ). The MRF estimates over the wide ranges of T 1 and T 2 values have less than 5% variation, except for the shortest T 2 relaxation times where the method still maintains less than 8% variation. MRF measurements of T 1 and T 2 are highly repeatable over time and across wide ranges of T 1 and T 2 values. Magn Reson Med 78:1452-1457, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Comparison of elemental contents of Korean space foods using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Yong Sam Chung; Sun Ha Kim; Gwang Min Sun; Jong Myoung Lim; Jong Hwa Moon; Kye Hong Lee; Young Jin Kim; Jong Il Choi; Ju Woon Lee

2012-01-01

The analysis of mineral contents in space foods is needed to obtain an information on a comprehensive elemental composition as well as the investigation on the effects of human nutrition and health based on the dietary intake of mineral elements. Recently, six items of new Korean space foods (KSFs) such as kimchi, bibimbap, bulgogi, a ramen, a mulberry beverage and a fruit punch which was developed by the KAERI, and the contents of more than 15 elements in the samples were examined by using instrumental neutron activation analysis (INAA). Five biological certified reference materials, NIST SRM were used for analytical quality control. The results were compared with those of common Korean foods reported, and these results will be applied toward the identification of irradiated foods. (author)

The Atomic Spectroscopy Data Center at the National Institute of Standards and Technology (NIST). Activities 1999-2001

International Nuclear Information System (INIS)

Wiese, W.L.

2001-01-01

Dr. Wiese discussed activities and trends at the NIST Data Centers in the last two years. He reviewed priorities covered in data work and reviewed the bibliographic and numerical databases now on their website. The Atomic Spectra Database (ASD) is their main atomic physics web database and this is a reference data, e.g., the wavelength data is generally accurate to six significant figures and transition probability data is certain to with less than ±50%. Dr. Wiese also reported about recent work on the compilation and evaluation of data for wavelengths and energy levels of elements Cu, Kr and Mo (and several others), which are fusion relevant

The Atomic Spectroscopy Data Center at the National Institute of Standards and Technology (NIST). Activities 1999-2001

Energy Technology Data Exchange (ETDEWEB)

Wiese, W L

2001-12-01

Dr. Wiese discussed activities and trends at the NIST Data Centers in the last two years. He reviewed priorities covered in data work and reviewed the bibliographic and numerical databases now on their website. The Atomic Spectra Database (ASD) is their main atomic physics web database and this is a reference data, e.g., the wavelength data is generally accurate to six significant figures and transition probability data is certain to with less than {+-}50%. Dr. Wiese also reported about recent work on the compilation and evaluation of data for wavelengths and energy levels of elements Cu, Kr and Mo (and several others), which are fusion relevant.

Optical Passive Sensor Calibration for Satellite Remote Sensing and the Legacy of NOAA and NIST Cooperation.

Science.gov (United States)

Datla, Raju; Weinreb, Michael; Rice, Joseph; Johnson, B Carol; Shirley, Eric; Cao, Changyong

2014-01-01

This paper traces the cooperative efforts of scientists at the National Oceanic and Atmospheric Administration (NOAA) and the National Institute of Standards and Technology (NIST) to improve the calibration of operational satellite sensors for remote sensing of the Earth's land, atmosphere and oceans. It gives a chronological perspective of the NOAA satellite program and the interactions between the two agencies' scientists to address pre-launch calibration and issues of sensor performance on orbit. The drive to improve accuracy of measurements has had a new impetus in recent years because of the need for improved weather prediction and climate monitoring. The highlights of this cooperation and strategies to achieve SI-traceability and improve accuracy for optical satellite sensor data are summarized.

Quantification and isotope ratio measurement of boron in U3Si2 by inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Saha, Abhijit; Deb, S.B.; Nagar, B.K.; Saxena, M.K.; Samanta, Papu

2014-01-01

An analytical methodology was developed for precise quantification and isotope ratio measurement of boron in U 3 Si 2 matrix by using ICP-MS after matrix separation. The analytical technique was validated by recovery studies employing standard addition method and the accuracy in isotope ratio measurement was improved by correcting the bias factor after analyzing NIST SRM951. The quantification of B in the three U 3 Si 2 samples was found in the range of 2.32-3.90 μg g -1 with a maximum standard deviation of 3%. The 10 B/ 11 B value in the three samples was found to be 0.2455±0.0042, 0.2451±0.0036 and 0.2452±0.0041. (author)

Absolute Ca Isotopic Measurement Using an Improved Double Spike Technique

Directory of Open Access Journals (Sweden)

Jason Jiun-San Shen

2009-01-01

Full Text Available A new vector analytical method has been developed in order to obtain the true isotopic composition of the 42Ca-48Ca double spike. This is achieved by using two different sample-spike mixtures combined with the double spike and natural Ca data. Be cause the natural sample (two mixtures and the spike should all lie on a single mixing line, we are able to con strain the true isotopic composition of our double spike using this new approach. Once the isotopic composition of the Ca double spike is established, we are able to obtain the true Ca isotopic composition of the NIST Ca standard SRM915a, 40Ca/44Ca = 46.537 ± 2 (2sm, n = 55, 42Ca/44Ca = 0.31031 ± 1, 43Ca/44Ca = 0.06474 ± 1, and 48Ca/44Ca = 0.08956 ± 1. De spite an off set of 1.3% in 40Ca/44Ca between our result and the previously re ported value (Russell et al. 1978, our data indicate an off set of 1.89__in 40Ca/44Ca between SRM915a and seawater, entirely consistent with the published results.

EDXRF applied to the chemical element determination of small invertebrate samples

Energy Technology Data Exchange (ETDEWEB)

Magalhaes, Marcelo L.R.; Santos, Mariana L.O.; Cantinha, Rebeca S.; Souza, Thomas Marques de; Franca, Elvis J. de, E-mail: marcelo_rlm@hotmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: rebecanuclear@gmail.com, E-mail: thomasmarques@live.com.pt, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2015-07-01

Energy Dispersion X-Ray Fluorescence - EDXRF is a fast analytical technique of easy operation, however demanding reliable analytical curves due to the intrinsic matrix dependence and interference during the analysis. By using biological materials of diverse matrices, multielemental analytical protocols can be implemented and a group of chemical elements could be determined in diverse biological matrices depending on the chemical element concentration. Particularly for invertebrates, EDXRF presents some advantages associated to the possibility of the analysis of small size samples, in which a collimator can be used that directing the incidence of X-rays to a small surface of the analyzed samples. In this work, EDXRF was applied to determine Cl, Fe, P, S and Zn in invertebrate samples using the collimator of 3 mm and 10 mm. For the assessment of the analytical protocol, the SRM 2976 Trace Elements in Mollusk produced and SRM 8415 Whole Egg Powder by the National Institute of Standards and Technology - NIST were also analyzed. After sampling by using pitfall traps, invertebrate were lyophilized, milled and transferred to polyethylene vials covered by XRF polyethylene. Analyses were performed at atmosphere lower than 30 Pa, varying voltage and electric current according to the chemical element to be analyzed. For comparison, Zn in the invertebrate material was also quantified by graphite furnace atomic absorption spectrometry after acid treatment (mixture of nitric acid and hydrogen peroxide) of samples have. Compared to the collimator of 10 mm, the SRM 2976 and SRM 8415 results obtained by the 3 mm collimator agreed well at the 95% confidence level since the E{sub n} Number were in the range of -1 and 1. Results from GFAAS were in accordance to the EDXRF values for composite samples. Therefore, determination of some chemical elements by EDXRF can be recommended for very small invertebrate samples (lower than 100 mg) with advantage of preserving the samples. (author)

Direct calibration of GC/MS systems using SRM (Standard Reference Material) gas cylinders. Project report, January 1984-August 1985

International Nuclear Information System (INIS)

Byrd, G.D.; Richie, K.L.; Sniegoski, L.T.; White, E.

1985-10-01

A cryogenic trapping system has been developed for use in calibrating GC/MS systems for the analysis of volatile organic compounds. This system provides for direct Standard Reference Material (SRM) traceability on data generated on gaseous samples. The cryogenic trap is a coil of stainless steel tubing immersed in a cryogen to trap and preconcentrate organic species present in a gaseous sample. The trap also contains a heated injection port for the addition of isotopically labeled compounds for use in isotope dilution measurements. The first part of this research is concerned with the development of IDMS as an independent method for the quantification of analytes in gaseous samples to be used as standards. Results are presented for the determination of bromobenzene in nitrogen at nominal concentrations of 1 and 25 ppb. In the second part of the research, a calibration curve method was developed for using these standards in auditing the performance of GC/MS systems

Solid sampling-graphite furnace atomic absorption spectrometry for the direct determination of boron in plant tissues

International Nuclear Information System (INIS)

Resano, M.; Briceno, J.; Aramendia, M.; Belarra, M.A.

2007-01-01

In this work, the potential of graphite furnace atomic absorption spectrometry for the direct determination of B in plant tissues has been investigated. Three certified reference materials (NIST SRM 1570a spinach leaves, NIST SRM 1573a tomato leaves and BCR CRM 679 white cabbage) were selected for this study, the goal always being to develop a fast procedure that could be robust enough to provide a satisfactory performance for all of them, without any modifications in the conditions applied. The use of a suitable chemical modifier was found to be essential for obtaining a reproducible and sufficiently sensitive signal for boron solutions. In this regard, the performance of the combination of citric acid plus W (added as a permanent modifier) was noteworthy, resulting in well-defined signal profiles, a remarkable analyte stabilization during the pyrolysis step (up to 2100 deg. C) and minimal memory effects. This mixture of modifiers provided a good performance for the direct analysis of solid samples as well, but only if a suitable temperature program, favoring the interaction between the analyte and the modifiers, was used. Thus, such a temperature program, with two pyrolysis steps and the addition of NH 4 NO 3 in order to carry out the in situ sample microdigestion, was optimized. Under these conditions, the peak areas obtained for both solid samples and aqueous standards were comparable. Finally, the analysis of the samples was carried out. In all cases, a good agreement with the certified values was obtained, while R.S.D. values ranged between 6 and 10%. It can be concluded that the method proposed shows significant advantages for the determination of this complicated element in solid samples such as the use of aqueous standards for calibration, a high sample throughput (20 min per sample), a suitable limit of detection (0.3 μg g -1 ) and reduced risk of analyte losses and contamination

IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

Science.gov (United States)

Vanderdeelen, Jan

2012-06-01

The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO3 types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO3. H2O), the hexahydrate ikaite (CaCO3.6H2O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

Elemental mapping of medieval teeth using XRF technique

International Nuclear Information System (INIS)

Muja, Cristina; Therese, Laurent; Guillot, Philippe

2011-01-01

Full text: Recent developments in X-Ray Fluorescence micro-analysis techniques made the traditional range of XRF applications expand, benefiting from the combination of single point analysis with high spatial element imaging. The sample is scanned through the X-Ray beam and corresponding spectra are continuously read from the detector and correlated to a particular position on the sample. In this work, elemental concentrations were obtained by X-ray fluorescence (XRF) technique (Jobin Yvon Horiba XGT-5000 instrument) offering detailed elemental analysis. The instrument is equipped with a tungsten X-ray tube and a beryllium window, operating at 50 kV with a beam collimator of 100μm in diameter to irradiate the sample and with a Si detector. Tooth mapping provided semi-quantitative information and highlighted the regions of interest. Then multi-points analysis was used to obtain quantitative results on calcium, phosphorus, strontium and iron. As the chemical composition of dental tissues is similar to the one of bone tissue, the certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for calibration. In this study, only permanent first molars were selected for analysis. The material comes from the medieval cemetery (XII th . XIII th ) of Feldioara (Bra.ov County, Romania). In the same time, modern teeth were used as reference. The top of the tooth was removed using a diamond disk, with a cut lying perpendicular to the dental cusps, creating a flat transversal surface to be characterized. XRF elemental (Ca, P, Sr, Fe) and ratio (Ca/P, Sr/Ca, Sr/Fe) distribution images for dental tissues (enamel and dentin) were obtained from past and modern teeth with and without caries and the results are presented and discussed. The analysis of the spatial element distribution in the teeth tissues revealed severe alterations in elemental composition of both enamel and dentin from the regions affected by caries that were confirmed by the multi

Elemental mapping of medieval teeth using XRF technique

Energy Technology Data Exchange (ETDEWEB)

Muja, Cristina [Laboratoire Diagnostics des Plasma, CUFR J.F.C, Albi (France); Faculty of Biology, University of Bucharest (Romania); Vasile Parvan Institute of Archaeology, Bucharest (Romania); Therese, Laurent; Guillot, Philippe, E-mail: philippe.guillot@univ-jfc.fr [Laboratoire Diagnostics des Plasma, CUFR J.F.C, Albi (France)

2011-07-01

Full text: Recent developments in X-Ray Fluorescence micro-analysis techniques made the traditional range of XRF applications expand, benefiting from the combination of single point analysis with high spatial element imaging. The sample is scanned through the X-Ray beam and corresponding spectra are continuously read from the detector and correlated to a particular position on the sample. In this work, elemental concentrations were obtained by X-ray fluorescence (XRF) technique (Jobin Yvon Horiba XGT-5000 instrument) offering detailed elemental analysis. The instrument is equipped with a tungsten X-ray tube and a beryllium window, operating at 50 kV with a beam collimator of 100{mu}m in diameter to irradiate the sample and with a Si detector. Tooth mapping provided semi-quantitative information and highlighted the regions of interest. Then multi-points analysis was used to obtain quantitative results on calcium, phosphorus, strontium and iron. As the chemical composition of dental tissues is similar to the one of bone tissue, the certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for calibration. In this study, only permanent first molars were selected for analysis. The material comes from the medieval cemetery (XII{sup th} . XIII{sup th}) of Feldioara (Bra.ov County, Romania). In the same time, modern teeth were used as reference. The top of the tooth was removed using a diamond disk, with a cut lying perpendicular to the dental cusps, creating a flat transversal surface to be characterized. XRF elemental (Ca, P, Sr, Fe) and ratio (Ca/P, Sr/Ca, Sr/Fe) distribution images for dental tissues (enamel and dentin) were obtained from past and modern teeth with and without caries and the results are presented and discussed. The analysis of the spatial element distribution in the teeth tissues revealed severe alterations in elemental composition of both enamel and dentin from the regions affected by caries that were confirmed by the

Determination of trace elements in Pre-Hispanic ceramics from Chile's Central Zone using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Andonie, O; Munoz, L; Kohnnenkamp, I; Falabella, F

2000-01-01

was validated with coal fly ash reference materials (NIST SRM 1633b) and brick clay (NIST SRM 679). An initial group of 100 samples was analyzed using the validated procedure. The results obtained will be statistically analyzed using the cluster, principal components and discriminant analysis techniques. (author)

Elemental characterization of bread and durum wheat by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Catarina Galinha; Maria do Carmo Freitas; Pacheco, A.M.G.

2013-01-01

Cereals are by far the most significant agricultural crops, not only due to the sheer amount of their gross-tonnage production and prevalence in human diets worldwide, but also as food vehicles of important items for human nutrition and wellness at large-proteins, dietary fibers and oligoelements, such as selenium, calcium, zinc and iron, to name just a few. Still, some micronutrients feature an uneven distribution in the upper continental crust, and thus in cultivation soils deriving therefrom. Whether soils have always been poor in an essential element, or have just become deprived of it by intensive farming, the result is the same: insufficient soil-plant transfer, feeble-to-nonexistent plant uptake, and, therefore, unsatisfactory dietary distribution of that element through the food chain. Countries that implemented corrective measures or programs of crop biofortification and consumer education have been successful in dealing with some micronutrients' deficiencies. Given their relative weight in Portuguese diets, cereals are obvious candidates for crop-supplementation strategies that may contribute to an upgrade in the health status of the whole population. A good knowledge of element-baseline data for major cereal varieties (plants) and main production areas (soils) is a pre-requisite though. The present work was aimed at an elemental characterization of cereals and soils from relevant wheat-producing areas of mainland Portugal. This paper is focused on wheat samples-bread and durum wheats; Triticum aestivum L. (Farak and Jordao cultivars) and Triticum durum Desf. (Don Duro and Simeto cultivars), respectively-from the 2009 campaign, collected at Tras-os-Montes, Alto Alentejo and Baixo Alentejo (inland regions). Elemental concentrations were determined by instrumental neutron activation analysis (INAA; k 0 -variant), and assessed with the k 0 -IAEA software. Quality control was asserted through the analysis of NIST-SRM R 1567a (Wheat Flour), NIST-SRM R 1568a

Evaluation of solid-phase microextraction conditions for the determination of polycyclic aromatic hydrocarbons in aquatic species using gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Aguinaga, N.; Campillo, N.; Vinas, P.; Hernandez-Cordoba, M. [University of Murcia, Department of Analytical Chemistry, Faculty of Chemistry, Murcia (Spain)

2008-06-15

This paper describes a headspace solid-phase microextraction (HS-SPME) procedure coupled to gas chromatography with mass spectrometric detection (GC-MS) for the determination of eight PAHs in aquatic species. The influence of various parameters on the PAH extraction efficiency was carefully examined. At 75 C and for an extraction time of 60 min, a polydimethylsiloxane-divinylbenzene (PDMS/DVB) fiber coating was found to be most suitable. Under the optimized conditions, detection limits ranged from 8 to 450 pg g{sup -1}, depending on the compound and the sample matrix. The repeatability varied between 7 and 15% (RSD). Accuracy was tested using the NIST SRM 1974b reference material. The method was successfully applied to different samples, and the studied PAHs were detected in several of the samples. (orig.)

IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

International Nuclear Information System (INIS)

De Visscher, Alex; Vanderdeelen, Jan

2012-01-01

The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO 3 types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO 3 · H 2 O), the hexahydrate ikaite (CaCO 3 ·6H 2 O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

Comparative study for essential elements determination in milk products samples by INAA and ICP-AES; Estudo comparativo na determinacao de elementos essenciais em amostras de produtos lacteos por AANI e ICP-AES

Energy Technology Data Exchange (ETDEWEB)

Kira, Carmen S. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil). Secao de Equipamentos Especializados; Maihara, Vera A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

2002-07-01

The mineral elements Ca, Fe, K, Mg, Na and Zn were analyzed in milk products by using instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The study included four types of cheese (mozzarella, minas, prato, parmesan), chocolate milk and yogurt. The samples were purchased from the local markets. Average concentrations ranged from 3668 (chocolate milk) to 16558 (parmesan cheese) mg/kg for Ca; from 2.61 (parmesan cheese) to 28.9 (chocolate milk) mg/kg for Fe; from 673 (mozzarella cheese) to 10492 (chocolate milk) mg/kg for K; from 398 (yogurt) to 2280 (minas cheese) mg/kg for Mg; from 1681 (yogurt) to 15248 (parmesan cheese) mg/kg for Na; from 12.1 (chocolate milk) to 71.8 (parmesan cheese) mg/kg for Zn. Two National Institute of Standards and Technology (NIST) standard reference materials (SRM 8435 Whole Milk Powder and SRM 1549 Non Fat Milk Powder) were analyzed to verify method accuracy. The statistic test used to determine the significance of the difference between the techniques was based on Unpaired t-Student test. Statistical test revealed no significance differences (P< 0,05) between the average values provided by the two methods for the most of determined elements. (author)

Comparative study for essential elements determination in milk products samples by INAA and ICP-AES

International Nuclear Information System (INIS)

Kira, Carmen S.; Maihara, Vera A.

2002-01-01

The mineral elements Ca, Fe, K, Mg, Na and Zn were analyzed in milk products by using instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The study included four types of cheese (mozzarella, minas, prato, parmesan), chocolate milk and yogurt. The samples were purchased from the local markets. Average concentrations ranged from 3668 (chocolate milk) to 16558 (parmesan cheese) mg/kg for Ca; from 2.61 (parmesan cheese) to 28.9 (chocolate milk) mg/kg for Fe; from 673 (mozzarella cheese) to 10492 (chocolate milk) mg/kg for K; from 398 (yogurt) to 2280 (minas cheese) mg/kg for Mg; from 1681 (yogurt) to 15248 (parmesan cheese) mg/kg for Na; from 12.1 (chocolate milk) to 71.8 (parmesan cheese) mg/kg for Zn. Two National Institute of Standards and Technology (NIST) standard reference materials (SRM 8435 Whole Milk Powder and SRM 1549 Non Fat Milk Powder) were analyzed to verify method accuracy. The statistic test used to determine the significance of the difference between the techniques was based on Unpaired t-Student test. Statistical test revealed no significance differences (P< 0,05) between the average values provided by the two methods for the most of determined elements. (author)

Analysis of JPSS J1 VIIRS Polarization Sensitivity Using the NIST T-SIRCUS

Science.gov (United States)

McIntire, Jeffrey W.; Young, James B.; Moyer, David; Waluschka, Eugene; Oudrari, Hassan; Xiong, Xiaoxiong

2015-01-01

The polarization sensitivity of the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) measured pre-launch using a broadband source was observed to be larger than expected for many reflective bands. Ray trace modeling predicted that the observed polarization sensitivity was the result of larger diattenuation at the edges of the focal plane filter spectral bandpass. Additional ground measurements were performed using a monochromatic source (the NIST T-SIRCUS) to input linearly polarized light at a number of wavelengths across the bandpass of two VIIRS spectral bands and two scan angles. This work describes the data processing, analysis, and results derived from the T-SIRCUS measurements, comparing them with broadband measurements. Results have shown that the observed degree of linear polarization, when weighted by the sensor's spectral response function, is generally larger on the edges and smaller in the center of the spectral bandpass, as predicted. However, phase angle changes in the center of the bandpass differ between model and measurement. Integration of the monochromatic polarization sensitivity over wavelength produced results consistent with the broadband source measurements, for all cases considered.

Instrumental neutron activation analysis potentialities in archaeological ceramics studies

International Nuclear Information System (INIS)

Paiva, Rosemeire P.; Munita, Casimirio S.; Alves, Marcia A.

1999-01-01

In this work, precision and sensitivity of the determination of As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn in ceramic samples by INAA were evaluated. Two clay samples Brick Clay (NIST-SRM-697 reference material)and Ohio Red Clay (a well known clay sample) were analyzed for this purpose. Archaeological ceramic fragments from Agua Limpa Site, in Monte Alto city, SP were also analyzed. The archaeological ceramics were produced in the quotidian activities of non writing preterite societies, in sedentarization process. The ceramic chemical information are used to identify raw material sources and to study production and distribution models, which allow the reconstruction of the socio-cultural development and integration of extinguished societies. (author)

Producing Homogeneity as a Historical Tradition. Neo-conservatism, Precarity and Citizenship Education in Poland

Czech Academy of Sciences Publication Activity Database

Červinková, Hana

2016-01-01

Roč. 14, č. 3 (2016), s. 43-55 ISSN 2051-0969 Institutional support: RVO:68378076 Keywords : citizenship * precarity * Poland * citizenship education * neoliberalism Subject RIV: AC - Archeology, Anthropology, Ethnology

Quantitative analysis of UV-A shock and short term stress using iTRAQ, pseudo selective reaction monitoring (pSRM) and GC-MS based metabolite analysis of the cyanobacterium Nostoc punctiforme ATCC 29133.

Science.gov (United States)

Wase, Nishikant; Pham, Trong Khoa; Ow, Saw Yen; Wright, Phillip C

2014-09-23

A quantitative proteomics and metabolomics analysis was performed using iTRAQ, HPLC and GC-MS in the filamentous cyanobacterium Nostoc punctiforme ATCC 29133 to understand the effect of short and long term UV-A exposure. Changes in the proteome were measured for short-term stress (4-24h) using iTRAQ. Changes in the photosynthetic pigments and intracellular metabolites were observed at exposures of up to 7days (pigments) and up to 11days (intracellular metabolites). To assess iTRAQ measurement quality, pseudo selected reaction monitoring (pSRM) was used, with this confirming underestimation of protein abundance levels by iTRAQ. Our results suggest that short term UV-A radiation lowers the abundance of PS-I and PS-II proteins. We also observed an increase in abundance of intracellular redox homeostasis proteins and plastocyanin. Additionally, we observed statistically significant changes in scytonemin, Chlorophyll A, astaxanthin, zeaxanthin, and β-carotene. Assessment of intracellular metabolites showed significant changes in several, suggesting their potential role in the Nostoc's stress mitigation strategy. Cyanobacteria under UV-A radiation have reduced growth due to intensive damage to essential functions, but the organism shows a defense response by remodeling bioenergetics pathway, induction of the UV protection compound scytonemin and increased levels of proline and tyrosine as a mitigation response. The effect of UV-A radiation on the proteome and intracellular metabolites of N. punctiforme ATCC 29133 including photosynthetic pigments has been described. We also verify the expression of 13 iTRAQ quantified protein using LC-pSRM. Overall we observed that UV-A radiation has a drastic effect on the photosynthetic machinery, photosynthetic pigments and intracellular amino acids. As a mitigation strategy against UV-A radiation, proline, glycine, and tyrosine were accumulated. Copyright © 2014. Published by Elsevier B.V.

Measured Polarized Spectral Responsivity of JPSS J1 VIIRS Using the NIST T-SIRCUS

Science.gov (United States)

McIntire, Jeff; Young, James B.; Moyer, David; Waluschka, Eugene; Xiong, Xiaoxiong

2015-01-01

Recent pre-launch measurements performed on the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) using the National Institute of Standards and Technology (NIST) Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources (T-SIRCUS) monochromatic source have provided wavelength dependent polarization sensitivity for select spectral bands and viewing conditions. Measurements were made at a number of input linear polarization states (twelve in total) and initially at thirteen wavelengths across the bandpass (later expanded to seventeen for some cases). Using the source radiance information collected by an external monitor, a spectral responsivity function was constructed for each input linear polarization state. Additionally, an unpolarized spectral responsivity function was derived from these polarized measurements. An investigation of how the centroid, bandwidth, and detector responsivity vary with polarization state was weighted by two model input spectra to simulate both ground measurements as well as expected on-orbit conditions. These measurements will enhance our understanding of VIIRS polarization sensitivity, improve the design for future flight models, and provide valuable data to enhance product quality in the post-launch phase.

IUPAC-NIST Solubility Data Series. 95. Alkaline Earth Carbonates in Aqueous Systems. Part 2. Ca

Energy Technology Data Exchange (ETDEWEB)

De Visscher, Alex; Vanderdeelen, Jan [Department of Chemical and Petroleum Engineering, and Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada); Department of Applied Analytical and Physical Chemistry, Faculty of Bioscience Engineering, Ghent University, B-9000 Ghent (Belgium)

2012-06-15

The alkaline earth carbonates are an important class of minerals. This article is part of a volume in the IUPAC-NIST Solubility Data Series that compiles and critically evaluates solubility data of the alkaline earth carbonates in water and in simple aqueous electrolyte solutions. Part 1 outlined the procedure adopted in this volume, and presented the beryllium and magnesium carbonates. Part 2, the current paper, compiles and critically evaluates the solubility data of calcium carbonate. The chemical forms included are the anhydrous CaCO{sub 3} types calcite, aragonite, and vaterite, the monohydrate monohydrocalcite (CaCO{sub 3}{center_dot} H{sub 2}O), the hexahydrate ikaite (CaCO{sub 3}{center_dot}6H{sub 2}O), and an amorphous form. The data were analyzed with two model variants, and thermodynamic data of each form consistent with each of the models and with the CODATA key values for thermodynamics are presented.

Visualizing Magnetic domain of Electric Steel using Grating Interferometer at NG6 of NIST

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Ju; Oh, Oh Sung; Lee, Se Ho; Kim, Dae Seung; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Kim, Jong Yul [KAERI, Daejeon (Korea, Republic of); Kwon, Oh Yeoul [Pohang Iron and Steel Company, Pohang (Korea, Republic of); Hussey, D. S.; Jacobson, D. L.; Lamannad, J. M. [NIST, Gaithersburg (United States)

2016-05-15

The Grating Interferometer is one of new imaging techniques provides improved contrast images, Phase Contrast Image and Dark-Field Image, which have never been seen before by conventional radiography. Neutron Dark-Field Imaging (NDFI) suggests new approach for material science providing the scattering image caused by the micro-structure of object. We attracted to the application of NDFI for material science, the electric steel which produce magnetic scattering information especially. In this study, we developed 1 dimensional gratings using gadox filling method to make the Talbot-Lau Interferometer (TLI). The experiment was conducted at cold neutron imaging facility NG6 of National Institute of Standards and Technologies, NIST. We confirmed that the 3 order Talbot-Lau type of neutron grating interferometer which is composed of gratings made by gadox filling method is well operated at cold neutron imaging beamline. NDFI is definitely powerful visualizing tool for material science, especially magnetic materials. In further study, we will research electric steel more in realistic conditions when it is worked as a component of electric motor.

Calcium Isotopic Composition of Bulk Silicate Earth

Science.gov (United States)

Kang, J.; Ionov, D. A.; Liu, F.; Zhang, C.; Zhang, Z.; Huang, F.

2016-12-01

Ca isotopes are used to study the accretion history of the Earth and terrestrial planets, but, Ca isotopic composition of the Bulk Silicate Earth (BSE) remains poorly constrained [1]. To better understand the Ca isotopic composition of BSE, we analyzed 22 well studied peridotite xenoliths from Tariat (Mongolia), Vitim (southern Siberia) and Udachnaya (Siberian Craton). These samples include both fertile and highly depleted garnet and spinel peridotites that show no or only minor post-melting metasomatism or alteration. Ca isotope measurements were done on a Triton-TIMS using double spike method at the Guangzhou Institute of Geochemistry, CAS. The data are reported as δ44/40Ca (relative to NIST SRM 915a). Results for geostandards are consistent with those from other laboratories. 2 standard deviations of SRM 915a analyses are 0.13‰ (n=48). δ44/40Ca of both and fertile and refractory peridotites range from 0.79 to 1.07‰ producing an average of 0.93±0.12‰ (2SD). This value defines the Ca isotopic composition of the BSE, which is consistent with the average δ44/40Ca of oceanic basalts ( 0.90‰)[2,3]. [1] Huang et al (2010) EPSL 292; [2] Valdes et al (2014) EPSL 394; [3]DePaolo (2004) RMG 55.

A new method in estimation of total hexavalent chromium in Portland pozzolan cement; Un nuevo método en la determinación del cromo hexavalente total en cemento Portland puzolánico.

Energy Technology Data Exchange (ETDEWEB)

Sharma, R.; Sharma, D.

2017-07-01

Variamine blue was used first time for the detection of hexavalent chromium from cement samples. In present method, cement was treated sequentially with water, sulphate and carbonate buffer to extract soluble, sparingly soluble and insoluble hexavalent chromium respectively. Extracted Cr (VI) was determined using variamine blue as chromogenic reagent. The determination is based on the reaction of hexavalent chromium with potassium iodide in an acid medium to liberate iodine. This oxidizes variamine blue to form a violet coloured species having an absorption to maximum at 556 nm. Energy-dispersive X-ray spectroscopy (EDX) and Infrared Spectroscopy (IR) confirmed the complete extraction of hexavalent chromium by sequential extraction process. SRM 2701 (Reference material from NIST, USA) was used for revalidating the results. The percentage of recovery for proposed and reference method (diphelycarbazide method) varied from 98.5 to 101 and 97.5 to 100.5. Whereas, their relative error percentage varied from -1.5 to 0.33 and -2.5 to 0.5. [Spanish] El azul de variamina se utilizó por primera vez para la detección de cromo hexavalente en muestras de cemento. En el presente método, el cemento se trató secuencialmente con agua, y tampones sulfato y carbonato para extraer el cromo hexavalente soluble, poco soluble e insoluble, respectivamente. El Cr (VI) extraído se determinó utilizando azul de variamina como reactivo cromógeno, por reacción del cromo hexavalente con yoduro de potasio en un medio ácido para liberar yodo. Esto oxida al azul de variamina para formar una especie de color violeta con una absorción máxima a 556 nm. El análisis por energía dispersiva de rayos X (EDX) y la espectroscopía de infrarrojos (IR) confirmaron la extracción completa de cromo hexavalente mediante el proceso de extracción secuencial. Se utilizó SRM 2701 (material de referencia de NIST, EE.UU.) para validar los resultados. El porcentaje de recuperación para el m

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Deepak [ORNL; Van Berkel, Gary J [ORNL

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45 min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.

Analysis of Loss-of-Coolant Accidents in the NIST Research Reactor - Early Phase

Energy Technology Data Exchange (ETDEWEB)

Baek, Joo S.; Diamond, David

2016-12-06

A study of the fuel temperature during the early phase of a loss-of-coolant accident (LOCA) in the NIST research reactor (NBSR) was completed. Previous studies had been reported in the preliminary safety analysis report for the conversion of the NBSR from high-enriched uranium (HEU) fuel to low-enriched (LEU) fuel. Those studies had focused on the most vulnerable LOCA situation, namely, a double-ended guillotine break in the time period after reactor trip when water is drained from either the coolant channels inside the fuel elements or the region outside the fuel elements. The current study fills in a gap in the analysis which is the early phase of the event when there may still be water present but the reactor is at power or immediately after reactor trip and pumps have tripped. The calculations were done, for both the current HEU-fueled core and the proposed LEU core, with the TRACE thermal-hydraulic systems code. Several break locations and different break sizes were considered. In all cases the increase in the clad (or fuel meat) temperature was relatively small so that a large margin to the temperature threshold for blistering (the Safety Limit for the NBSR) remained.

A simple and sensitive vortex-assisted ionic liquid-dispersive microextraction and spectrophotometric determination of selenium in food samples.

Science.gov (United States)

Bağda, Esra; Tüzen, Mustafa

2017-10-01

In the present study, a novel and eco-friendly vortex-assisted ionic liquid-based microextraction method was developed for the determination of selenium in food. The microextraction method is based on the liberation of iodine in the presence of selenium; the liberated iodine reacts with I - to form I 3 - . Anionic I 3 - reacts with cationic crystal violet dye, and the product is extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate phase in the presence of Triton X-114. The proposed method is linear in the range of 2.0-70µgL -1 and has a detection limit of 9.8×10 -2 µgL -1 . Relative standard deviations were 3.67% and 2.89% for the five replicate measurements of 14 and 35µgL -1 Se(IV), respectively. The proposed method was successfully applied to different food samples (NIST SRM 2976 mussel tissue, pepper, ginger, wheat flour, red lentil, traditional soup, cornflour, cornstarch, and garlic) after microwave digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of lead associated with airborne particulate matter by flame atomic absorption and wave-length dispersive x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Talebi, S.M.

1997-01-01

The lead content of airborne particulate matter was determined by flame atomic absorption spectrometry (FAAS) following digestion with a mixture of nitric acid and hydrogen peroxide and also by wave-length dispersive x-ray fluorescence (WDXRF). The extraction procedure was checked by analyzing a standard reference material of airborne particulate matter (NIST, SRM -1648). It was concluded that lead can quantitatively (98%) be extracted from airborne particulate matter by the leaching process. A five-stage sequential extraction was performed to assess the potential mobility of lead associated with airborne particulate matter. Comparison of the airborne particulate lead measured by WDXRF to that measured by FAAS showed good agreement. The WDXRF method requires no time-consuming sample preparation or use of environmentally unfriendly solvents. The technique is suggested for direct determination of lead in airborne particulate matter in air pollution studies. (author)

Results and Systematic Studies of the UCN Lifetime Experiment at NIST

Science.gov (United States)

Huffer, Craig Reeves

The neutron beta-decay lifetime is important in understanding weak interactions in the framework of the Standard Model, and it is an input to nuclear astrophysics and Big Bang Nucleosynthesis. Current measurements of the neutron beta-decay lifetime disagree, which has motivated additional experiments that are sensitive to different sets of systematic effects. An effort continues at the NIST Center for Neutron Research (NCNR) to improve the statistical and systematic limitations of an experiment to measure the neutron beta-decay lifetime using magnetically trapped UCN. In the experiment, a monoenergetic 0:89 nm cold neutron is incident on a superfluid 4He target within the minimum field region of an Ioffe type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (≈ 200 neV), and those in the appropriate spin state become trapped. The inverse process, upscattering of UCN, is suppressed by the low phonon density in the analysis, data, and systematics will be discussed. After accounting for the systematic effects the measured lifetime disagrees with the current PDG mean neutron beta-decay lifetime by about 9 of our standard deviations, which is a strong indication of unaccounted for systematic effects. Additional 3He contamination will be shown to be the most likely candidate for the additional systematic shift, which motivated the commissioning and initial operation of a heat flush purifier for purifying additional 4He. This work ends with a description of the 4He purifier and its performance.

A novel microextraction technique based on 1-hexylpyridinium hexafluorophosphate ionic liquid for the preconcentration of zinc in water and milk samples

International Nuclear Information System (INIS)

Abdolmohammad-Zadeh, H.; Sadeghi, G.H.

2009-01-01

A simple dispersive liquid-liquid microextraction methodology based on the application of 1-hexylpyridinium hexafluorophosphate [HPy][PF 6 ] ionic liquid (IL) as an extractant solvent was proposed for the preconcentration of trace levels of zinc as a prior step to determination by flame atomic absorption spectrometry (FAAS). Zinc was complexed with 8-hydroxyquinoline (oxine) and extracted into ionic liquid. Some effective factors that influence the microextraction efficiency such as pH, oxine concentration, amount of IL, ionic strength, temperature and centrifugation time were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.22 μg L -1 and 71, respectively. The relative standard deviation (RSD) for six replicate determinations of 13 μg L -1 Zn was 1.92%. In order to validate the developed method, a certified reference material (NIST SRM 1549) was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the trace determination of zinc in water and milk samples.

Development of a radiochemical procedure for certification of phosphorus implantation dose in silicon

International Nuclear Information System (INIS)

Paul, R.L.; Simons, D.S.

2002-01-01

The U.S. semiconductor industry relies heavily on secondary ion mass spectrometry (SIMS) for characterization of the depth distribution of dopants such as boron, arsenic, and phosphorus in silicon. To assist the industry in achieving high accuracy measurements, two Standard Reference Materials (SRMs) have been developed by NIST as SIMS calibration standards: SRM 2137 (Boron Implant in Silicon), certified by neutron depth profiling, and SRM 2134 (Arsenic Implant in Silicon), certified by instrumental neutron activation analysis. The industry is still in need of a phosphorus standard. Plans are currently underway to develop a phosphorus implant in silicon SRM, to be certified by radiochemical neutron activation analysis (RNAA). RNAA was chosen because other techniques lack the necessary sensitivity, chemical specificity and matrix independence to measure phosphorus at implantation levels. In order to assess the sensitivity, accuracy, and precision of RNAA for this work, preliminary measurements were carried out on six pieces of a phosphorus-implanted silicon wafer that was previously used in a round-robin study of SIMS measurement repeatability. Standards were prepared by depositing micro litre amounts of a standardized phosphorus solution on aluminum foil. A non-implanted silicon wafer was analysed as a blank. Samples were irradiated at a neutron fluency rate of 1 x 10 14 cm -2 s -1 to convert 31 P to 32 P, then mixed with milligram amounts of phosphorus carrier and dissolved in a mixture of nitric and hydrofluoric acids. Phosphorus was separated from the matrix by precipitation first as ammonium phosphomolybdate then as magnesium ammonium phosphate. The yield (fraction of recovered carrier) was determined gravimetrically as Mg(NH 4 )PO 4 .6H 2 O. 32 P was measured using a beta proportional counter. The measurements yielded a mean and standard deviation of (8.35 ± 0.20) x 10 14 atoms.cm -2 (relative standard deviation = 2.35 %), in agreement with both the nominal

Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life

Science.gov (United States)

Needelman, William M.; Zaretsky, Erwin V.

2014-01-01

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings. These equations for life factors were incorporated into the reference book, "STLE Life Factors for Rolling Bearings." These equations were normalized (LF = 1) to a 10-micrometer filter rating at Beta(sub x) = 200 (normal cleanliness) as it was then defined. Over the past 20 years, these life factors based on oil filtration have been used in conjunction with ANSI/ABMA standards and bearing computer codes to predict rolling bearing life. Also, additional experimental studies have been made by other investigators into the relationship between rolling bearing life and the size, number, and type of particle contamination. During this time period filter ratings have also been revised and improved, and they now use particle counting calibrated to a new National Institute of Standards and Technology (NIST) reference material, NIST SRM 2806, 1997. This paper reviews the relevant bearing life studies and describes the new filter ratings. New filter ratings, Beta(sub x(c)) = 200 and Beta(sub x(c)) = 1000, are benchmarked to old filter ratings, Beta(sub x) = 200, and vice versa. Two separate sets of filter LF values were derived based on the new filter ratings for roller bearings and ball bearings, respectively. Filter LFs can be calculated for the new filter ratings.

Evaluation of lead isotope compositions of NIST NBS 981 measured by thermal ionization mass spectrometer and multiple-collector inductively coupled plasma mass spectrometer

Directory of Open Access Journals (Sweden)

Honglin Yuan

2016-09-01

Full Text Available Because Pb isotopes can be used for tracing, they are widely used in many disciplines. The detection and analysis of Pb isotopes of bulk samples are usually conducted using thermal ionization mass spectrometer (TIMS and multiple-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, both of which need external reference materials with known isotopic compositions to correct for the mass discrimination effect produced during analysis. NIST NBS 981 is the most widely used reference material for Pb isotope analysis; however, the isotopic compositions reported by various analytical laboratories, especially those using TIMS, vary from each other. In this study, we statistically evaluated 229 reported TIMS analysis values collected by GeoReM in the last 30 years, 176 reported MC-ICP-MS analysis values, and 938 MC-ICP-MS analysis results from our laboratory in the last five years. After careful investigation, only 40 TIMS results were found to have double or triple spikes. The ratios of the overall weighted averages, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, obtained from 40 spiked TIMS reports and 1114 MC-ICP-MS results of NIST NBS 981 isotopes were 16.9406 ± 0.0003 (2s, 15.4957 ± 0.0002 (2s, and 36.7184 ± 0.0007 (2s, respectively.

Determination of selenium in cereals, legumes and dry fruits from southeastern Spain for calculation of daily dietary intake

International Nuclear Information System (INIS)

Diaz-Alarcon, J.P.; Navarro-Alarcon, M.; Lopez-Garcia de la Serrana, H.; Lopez-Martinez, M.C.

1996-01-01

Hydride generation atomic absorption spectrometry was used to determine selenium content in cereals, legumes and dry fruits from the coast of the province of Granada (southeastern Spain). Accuracy was assured using both a NIST SRM 1572 and recovery experiments. The precision expressed as relative standard deviation (RSD) varied between 6.50% for seeds and 15.98% for bread. The highest selenium concentrations were found for dry fruits (294.6 ng/g), followed by legumes (111.8 ng/g), and the lowest for cereals (27.8 ng/g). Considering the average daily individual consumption of these foods in Andalusia (southern Spain), the daily dietary intake of selenium supplied by this source is 15.36 μg/day for an adult. The content of total selenium in corn samples taken from the zone is independent of both human and industrial activities (P 0.05)

National Needs for Appearance Metrology

Science.gov (United States)

Nadal, Maria E.

2003-04-01

Appearance greatly influences a customer's judgement of the quality and acceptability of manufactured products, as yearly there is approximately $700 billion worth of shipped goods for which overall appearance is critical to their sale. For example, appearance is reported to be a major factor in about half of automobile purchases. The appearance of an object is the result of a complex interaction of the light field incident upon the object, the scattering and absorption properties of the object, and human perception. The measurable attributes of appearance are divided into color (hue, saturation, and lightness) and geometry (gloss, haze). The nature of the global economy has increased international competition and the need to improve the quality of many manufactured products. Since the manufacturing and marketing of these products is international in scope, the lack of national appearance standard artifacts and measurement protocols results in a direct loss to the supplier. One of the primary missions of the National Institute of Standards and Technology (NIST) is to strengthen the U.S. economy by working with industry to develop and apply technology, measurements and standards. The NIST Physics Laboratory has established an appearance metrology laboratory. This new laboratory provides calibration services for 0^o/45^o color standards and 20^o°, 60^o°, and 85^o° specular gloss, and research in the colorimetric characterization of gonioapparent including a new Standard Reference Material for metallic coatings (SRM 2017) and measurement protocols for pearlescent coatings. These services are NIST's first appearance metrology efforts in many years; a response to needs articulated by industry. These services are designed to meet demands for improved measurements and standards to enhance the acceptability of final products since appearance often plays a major role in their acceptability.

Standards and measurements for assessing bone health-workshop report co-sponsored by the International Society for Clinical Densitometry (ISCD) and the National Institute of Standards and Technology (NIST).

Science.gov (United States)

Bennett, Herbert S; Dienstfrey, Andrew; Hudson, Lawrence T; Oreskovic, Tammy; Fuerst, Thomas; Shepherd, John

2006-01-01

This article reports and discusses the results of the recent ISCD-NIST Workshop on Standards and Measurements for Assessing Bone Health. The purpose of the workshop was to assess the status of efforts to standardize and compare results from dual-energy X-ray absorptiometry (DXA) scans, and then to identify and prioritize ongoing measurement and standards needs.

Glycan characterization of the NIST RM monoclonal antibody using a total analytical solution: From sample preparation to data analysis.

Science.gov (United States)

Hilliard, Mark; Alley, William R; McManus, Ciara A; Yu, Ying Qing; Hallinan, Sinead; Gebler, John; Rudd, Pauline M

Glycosylation is an important attribute of biopharmaceutical products to monitor from development through production. However, glycosylation analysis has traditionally been a time-consuming process with long sample preparation protocols and manual interpretation of the data. To address the challenges associated with glycan analysis, we developed a streamlined analytical solution that covers the entire process from sample preparation to data analysis. In this communication, we describe the complete analytical solution that begins with a simplified and fast N-linked glycan sample preparation protocol that can be completed in less than 1 hr. The sample preparation includes labelling with RapiFluor-MS tag to improve both fluorescence (FLR) and mass spectral (MS) sensitivities. Following HILIC-UPLC/FLR/MS analyses, the data are processed and a library search based on glucose units has been included to expedite the task of structural assignment. We then applied this total analytical solution to characterize the glycosylation of the NIST Reference Material mAb 8761. For this glycoprotein, we confidently identified 35 N-linked glycans and all three major classes, high mannose, complex, and hybrid, were present. The majority of the glycans were neutral and fucosylated; glycans featuring N-glycolylneuraminic acid and those with two galactoses connected via an α1,3-linkage were also identified.

Some issues for blast from a structural reactive material solid

Science.gov (United States)

Zhang, F.

2018-03-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

Transferability of ASTM/NIST alanine-polyethylene recipe at ISS. American Society for Testing and Materials/National Institute for Standards and Technology. Istituto Superiore de Sanita

Science.gov (United States)

De Angelis C; Fattibene; Onori; Petetti; Bartolotta; Sansone Santamaria A

2000-05-01

Alanine-polyethylene solid state dosimeters were prepared at Istituto Superiore di Sanita (ISS) following the recipe proposed by National Institute of Standards and Technology (NIST) with the goal of testing its transferability. Dosimeters were prepared using 95% alanine and 5% polyethylene, by weight. They are rugged and of increased sensitivity, repeatability and reproducibility as respect to the ISS alanine-paraffin pellets. Reproducibility of about 1% was obtained at 10 Gy and at 3 Gy if one single pellet or a stack of five dosimeters were used, respectively.

Grafting 3-mercaptopropyl trimethoxysilane on multi-walled carbon nanotubes surface for improving on-line cadmium(II) preconcentration from water samples

Energy Technology Data Exchange (ETDEWEB)

Corazza, Marcela Zanetti; Somera, Bruna Fabrin; Segatelli, Mariana Gava [Departamento de Quimica, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, PR 445, Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Tarley, Cesar Ricardo Teixeira, E-mail: tarley@uel.br [Departamento de Quimica, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, PR 445, Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Instituto Nacional de Ciencia e Tecnologia (INCT) de Bioanalitica, Universidade Estadual de Campinas (UNICAMP), Instituto de Quimica, Departamento de Quimica Analitica, Cidade Universitaria Zeferino, Vaz, s/n, CEP 13083-970, Campinas-SP (Brazil)

2012-12-15

certified reference material NIST SRM 1573a (tomato leaves) and standard reference material NIST SRM 1643e (trace elements in natural waters).

Tin isotope fractionation during magmatic processes and the isotope composition of the bulk silicate Earth

Science.gov (United States)

Wang, Xueying; Amet, Quentin; Fitoussi, Caroline; Bourdon, Bernard

2018-05-01

Tin is a moderately volatile element whose isotope composition can be used to investigate Earth and planet differentiation and the early history of the Solar System. Although the Sn stable isotope composition of several geological and archaeological samples has been reported, there is currently scarce information about the effect of igneous processes on Sn isotopes. In this study, high-precision Sn isotope measurements of peridotites and basalts were obtained by MC-ICP-MS with a double-spike technique. The basalt samples display small variations in δ124/116Sn ranging from -0.01 ± 0.11 to 0.27 ± 0.11‰ (2 s.d.) relative to NIST SRM 3161a standard solution, while peridotites have more dispersed and more negative δ124Sn values ranging from -1.04 ± 0.11 to -0.07 ± 0.11‰ (2 s.d.). Overall, basalts are enriched in heavy Sn isotopes relative to peridotites. In addition, δ124Sn in peridotites become more negative with increasing degrees of melt depletion. These results can be explained by different partitioning behavior of Sn4+ and Sn2+ during partial melting. Sn4+ is overall more incompatible than Sn2+ during partial melting, resulting in Sn4+-rich silicate melt and Sn2+-rich residue. As Sn4+ has been shown experimentally to be enriched in heavy isotopes relative to Sn2+, the effect of melting is to enrich residual peridotites in relatively more compatible Sn2+, which results in isotopically lighter peridotites and isotopically heavier mantle-derived melts. This picture can be disturbed partly by the effect of refertilization. Similarly, the presence of enriched components such as recycled oceanic crust or sediments could explain part of the variations in Sn isotopes in oceanic basalts. The most primitive peridotite analyzed in this study was used for estimating the Sn isotope composition of the BSE, with δ124Sn = -0.08 ± 0.11‰ (2 s.d.) relative to the Sn NIST SRM 3161a standard solution. Altogether, this suggests that Sn isotopes may be a powerful probe of

High-precision measurement of mercury isotope ratios in sediments using cold-vapor generation multi-collector inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Foucher, Delphine; Hintelmann, Holger

2006-01-01

An on-line Hg reduction technique using stannous chloride as the reductant was applied for accurate and precise mercury isotope ratio determinations by multi-collector (MC)-ICP/MS. Special attention has been paid to ensure optimal conditions (such as acquisition time and mercury concentration) allowing precision measurements good enough to be able to significantly detect the anticipated small differences in Hg isotope ratios in nature. Typically, internal precision was better than 0.002% (1 RSE) on all Hg ratios investigated as long as approximately 20 ng of Hg was measured with a 10-min acquisition time. Introducing higher amounts of mercury (50 ng Hg) improved the internal precision to 205 Tl/ 203 Tl correction coupled to a standard-sample bracketing approach. The large number of data acquired allowed us to validate the consistency of our measurements over a one-year period. On average, the short-term uncertainty determined by repeated runs of NIST SRM 1641d Hg standard during a single day was 202 Hg/ 198 Hg, 202 Hg/ 199 Hg, 202 Hg/ 200 Hg, and 202 Hg/ 201 Hg). The precision fell to 202 Hg/ 198 Hg expressed as δ values (per mil deviations relative to NIST SRM 1641d Hg standard solution) displayed differences from +0.74 to -4.00 permille. The magnitude of the Hg fractionation per amu was constant within one type of sample and did not exceed 1.00 permille. Considering all results (the reproducibility of Hg standard solutions, reference sediment samples, and the examination of natural samples), the analytical error of our δ values for the overall method was within ±0.28 permille (1 SD), which was an order of magnitude lower than the extent of fractionation (4.74 permille) observed in sediments. This study confirmed that analytical techniques have reached a level of long-term precision and accuracy that is sufficiently sensitive to detect even small differences in Hg isotope ratios that occur within one type of samples (e.g., between different sediments) and so

Development of an on-line low gas pressure cell for laser ablation-ICP-mass spectrometry

International Nuclear Information System (INIS)

Hirata, Takafumi

2007-01-01

An on-line low gas pressure cell device has been developed for elemental analysis using laser ablation-ICP-mass spectrometry (LA-ICPMS). Ambient gas in the sample cell was evacuated by a constant-flow diaphragm pump, and the pressure of the sample cell was controlled by changing the flow rate of He-inlet gas. The degree of sample re-deposition around the ablation pit could be reduced when the pressure of the ambient gas was lower than 50 kPa. Produced sample aerosol was drawn and taken from the outlet of the diaphragm pump, and directly introduced into the ICP ion source. The flow rate of He gas controls not only the gas pressure in the sample cell, but also the transport efficiency of the sample particles from the cell to the ICP, and the gas flow rate must be optimized to maximize the signal intensity of the analytes. The flow rates of the He carrier and Ar makeup gas were tuned to maximize the signal intensity of the analytes, and in the case of 238 U from the NIST SRM610 glass material, the signal intensity could be maximized with gas flow rates of 0.4 L/min for He and 1.2 L/min for Ar. The resulting gas pressure in the cell was 30-35 kPa. Using the low gas pressure cell device, the stability in the signal intensities and the resulting precision in isotopic ratio measurements were evaluated. The signal intensity profile of 63 Cu obtained by laser ablation from a metallic sample (NIST SRM976) demonstrated that typical spikes in the transient signal, which can become a large source of analytical error, were no longer found. The resulting precision in the 65 Cu/ 63 Cu ratio measurements was 2-3% (n=10, 2SD), which was half on the level obtained by laser ablation under atmospheric pressure (6-10%). The newly developed low-pressure cell device provides easier optimization of the operational conditions, together with smaller degrees of sample re-deposition and better stability in the signal intensity, even from a metallic sample. (author)

Nářeční atlasy slovanských jazyků: historie a současnost.

Czech Academy of Sciences Publication Activity Database

Kloferová, Stanislava

2015-01-01

Roč. 7 (2015), s. 43-55. ISBN 978-83-7654-182-2. ISSN 1898-9276 R&D Projects: GA ČR(CZ) GAP406/11/1786 Keywords : geolinguistics * linguistic atlas * dialect * Slavic languages Subject RIV: AI - Linguistics

Accident Analysis for the NIST Research Reactor Before and After Fuel Conversion

Energy Technology Data Exchange (ETDEWEB)

Baek J.; Diamond D.; Cuadra, A.; Hanson, A.L.; Cheng, L-Y.; Brown, N.R.

2012-09-30

Postulated accidents have been analyzed for the 20 MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analysis has been carried out for the present core, which contains high enriched uranium (HEU) fuel and for a proposed equilibrium core with low enriched uranium (LEU) fuel. The analyses employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron transport calculations were performed with the MCNPX code to determine homogenized fuel compositions in the lower and upper halves of each fuel element and to determine the resulting neutronic properties of the core. The accident analysis employed a model of the primary loop with the RELAP5 code. The model includes the primary pumps, shutdown pumps outlet valves, heat exchanger, fuel elements, and flow channels for both the six inner and twenty-four outer fuel elements. Evaluations were performed for the following accidents: (1) control rod withdrawal startup accident, (2) maximum reactivity insertion accident, (3) loss-of-flow accident resulting from loss of electrical power with an assumption of failure of shutdown cooling pumps, (4) loss-of-flow accident resulting from a primary pump seizure, and (5) loss-of-flow accident resulting from inadvertent throttling of a flow control valve. In addition, natural circulation cooling at low power operation was analyzed. The analysis shows that the conversion will not lead to significant changes in the safety analysis and the calculated minimum critical heat flux ratio and maximum clad temperature assure that there is adequate margin to fuel failure.

Application of instrumental neutron activation analysis for the examination of oil pigments

International Nuclear Information System (INIS)

Chung, Y.S.; Kim, S.H.; Sun, G.M.; Lim, J.M.; Moon, J.H.; Kim, Y.J.; Lim, S.J.; Song, Y.N.; Kim, K.

2011-01-01

This study is to investigate the applicability of instrumental neutron activation analysis (INAA) as a non-destructive examination tool for the quantitative chemical composition analysis associated with authentication, restoration and conservation of art objects in the field of cultural heritage. The quantitative analysis of major, minor and trace elements in Rembrandt's registered oil pigments recently collected at the Korean market as one of the art objects was carried out using INAA facilities of the HANARO research reactor at the Korea Atomic Energy Research Institute in collaboration with the National Museum of Contemporary Art in Korea. Analytical quality control was implemented using NIST SRM 2709, certified reference materials and metal standards. The analytical results for seventeen characteristic elements of thirty-one measured elements were statistically treated to identify the characteristic correlations and patterns between color and source of oil pigment and similarity degree of constituents using a cluster and discriminate analysis. (orig.)

Determination of trace and toxic elements in Koran rice CRM by INAA, ICP and AAS

International Nuclear Information System (INIS)

Yong Sam Chung; Young Ju Chung; Kyung Haeng Cho; Joung Hae Lee

1997-01-01

Trace and toxic elements in Certified Reference Material (CRM) made of Korean rice at the Korea Research Institute of Standards and Science have been analyzed by Instrumental Neutron Activation Analysis (INAA). Data intercomparison from the measurement with those of Atomic Absorption Spectrometry (AAS) and Induced Coupled Plasma Spectrometry (ICPS) has been studied. The powdered samples were sterilized at 1.5 x 10 6 rad in the bottles using a 60 Co source after sieving and spiking to specific elements such as As, Cd, Cr, Cu and Hg and then the homogeneity of samples was assessed. Rice flour (SRM 1568a) and standard solutions made by the National Institute of Standards Technology (NIST) were used to construct the calibration curves for the INAA and the chemical methods, respectively. The uncertainties and concentration of constituent elements were determined and the possibility of their use for analytical quality control was considered. (author)

Investigation of chemical modifiers for the determination of lead in fertilizers and limestone using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction and slurry sampling

Energy Technology Data Exchange (ETDEWEB)

Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; Dessuy, Morgana B. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R., E-mail: mgrvale@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

2014-02-01

In this work, chemical modifiers in solution (Pd/Mg, NH{sub 4}H{sub 2}PO{sub 4} and NH{sub 4}NO{sub 3}/Pd) were compared with permanent modifiers (Ir and Ru) for the determination of lead in fertilizer and limestone samples using slurry sampling and graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. The analytical line at 283.3 nm was used due to some spectral interference observed at 217.0 nm. The NH{sub 4}H{sub 2}PO{sub 4} was abandoned due to severe spectral interference even at the 283.3-nm line. For Pd/Mg and NH{sub 4}NO{sub 3}/Pd the optimum pyrolysis and atomization temperatures were 900 °C and 1900 °C, respectively. For Ru and Ir, the integrated absorbance signal was stable up to pyrolysis temperatures of 700 °C and 900 °C, respectively, and up to atomization temperature of 1700 °C. The limit of detection (LOD) was 17 ng g{sup −1} using Pd/Mg and 29 ng g{sup −1} using NH{sub 4}NO{sub 3}/Pd. Among the permanent modifiers investigated, the LOD was 22 ng g{sup −1} Pb for Ir and 10 ng g{sup −1} Pb for Ru. The accuracy of the method was evaluated using the certified reference material NIST SRM 695. Although Ru provided lower LOD, which can be attributed to a lower blank signal, only the modifiers in solution showed concordant values of Pb concentration for the NIST SRM 695 and the most of analyzed samples. Moreover, the Pd/Mg modifier provided the highest sensitivity and for this reason it is more suitable for the determination of Pb in fertilizers samples in slurry; besides this it presented a better signal-to-noise ratio than NH{sub 4}NO{sub 3}/Pd. - Highlights: • Lead has been determined in fertilizers using slurry sampling GF AAS. • The mixture of palladium and magnesium nitrates was found to be the ideal chemical modifier. • Calibration could be carried out against aqueous standard solutions. • The proposed method is much faster than the EPA method, which includes sample digestion.

Determination of Pu, Am and Cm in Environmental Samples

Energy Technology Data Exchange (ETDEWEB)

Lujaniene, G. [SRI Centre for Physical Sciences and Technology, Vilnius (Lithuania)

2013-07-15

The determination of actinides in the environmental samples at a lower detection limit is required for monitoring purposes and for environmental research. The method for Pu, Am and Cm measurements in soil and sediment samples provides high recoveries and good decontamination from interfering radionuclides. The main steps of the method involve digestion of the samples, separation of radionuclides from matrix using the TOPO /cyclohexane extraction and final purification using extraction Eichrom resins (TEVA, TRU). The accuracy and precision of Pu, Am and Cm analyses were tested using IAEA RM No 135, NIST SRM No 4350b, No 4357 and in intercomparison runs organized by the Riso National Laboratory, Denmark, and in the proficiency tests organized by National Physical Laboratory, UK. The method was applied for measurement of radionuclides in aerosol samples (ashes {approx}30 g), bottom sediments (50-80 g dr. wt) and soil (including Chernobyl soil) samples. (author)

A simple QuEChERS-like extraction approach for molecular chemical characterization of organic aerosols: application to nitrated and oxygenated PAH derivatives (NPAH and OPAH) quantified by GC-NICIMS.

Science.gov (United States)

Albinet, A; Nalin, F; Tomaz, S; Beaumont, J; Lestremau, F

2014-05-01

An extraction procedure based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) approach has been developed and used for analysis of particle-bound nitrated and oxygenated PAH derivatives (NPAH and OPAH, respectively). Several analytical conditions, for example GC injection temperature and MS detection settings, were optimized. This analytical procedure enabled simultaneous GC-NICIMS quantification of 32 NPAH and 32 OPAH (or other oxygenated compounds), including typical components of secondary organic aerosol (SOA) formed by photooxidation of PAH (e.g. 2-formyl-trans-cinnamaldehyde and 6H-dibenzo[b,d]pyran-6-one). The QuEChERS-like approach was optimized, including the nature of the extraction solvent, the sorbent used for clean-up, and extraction time. The final extraction procedure was based on brief mechanical agitation (vortex mixing for 1.5 min), with 7 mL acetonitrile as solvent. Because dispersive solid-phase extraction (d-SPE) did not provide satisfactory results, SPE using SiO2 was selected for sample purification. Identical results were obtained when the QuEChERS-like and traditional pressurised solvent extraction (PLE) procedures were compared for analysis of fortified ambient air particle samples. The procedure was validated by analysis of two aerosol standard reference materials (NIST SRM 1649b (urban dust) and SRM 2787 (fine particulate matter, extraction methods, including PLE, the QuEChERS-like procedure resulted in increased productivity and reduced extraction cost. This paper shows that QuEChERS-like extraction procedures can be suitably adapted for molecular chemical characterization of aerosol samples and could be extended to other categories of compound.

Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Shaheen, M.E.; Gagnon, J.E.; Fryer, B.J.

2015-01-01

Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using 66 Zn/ 63 Cu, 208 Pb/ 238 U, 232 Th/ 238 U, 66 Zn/ 232 Th and 66 Zn/ 208 Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to femtosecond laser ablation of NIST 610 and Brass

Determination of trace amounts of plutonium in environmental samples by RIMS using a high repetition rate solid state laser system

International Nuclear Information System (INIS)

Gruening, C.; Kratz, J.V.; Trautmann, N.; Waldek, A.; Huber, G.; Passler, G.; Wendt, K.

2001-01-01

A reliable and easy to handle high repetition rate solid state laser system has been set up for routine applications of Resonance Ionization Mass Spectrometry (RIMS). It consists of three Titanium-Sapphire (Ti:Sa) lasers pumped by one Nd:YAG laser, providing up to 3 W of tunable laser light each in a wavelength range from 725 nm to 895 nm. The isotope shifts for 238 Pu to 244 Pu have been measured in an efficient ionization scheme with λ 1 =420.76 nm, λ 2 =847.28 nm and λ 3 =767.53 nm. An overall detection efficiency of the RIMS apparatus of ε=1x10 -5 is routinely reached, resulting in a detection limit of 2x10 6 atoms (0.8 fg) of plutonium. The isotopic compositions of synthetic samples and the NIST standard reference material SRM996 were measured. The content of 238 Pu to 242 Pu has been determined in dust samples from the surroundings of a nuclear power plant and 244 Pu was determined in urine samples for the National Radiation Protection Board (NRPB), U.K. Routine operation of plutonium ultratrace detection could thus be established

A Liquid Deuterium Cold Neutron Source for the NIST Research Reactor - Conceptual Design

International Nuclear Information System (INIS)

Williams, R. E.; Middleton, M.; Kopetka, P.; Rowe, J. M.; Brand, P. C.

2013-01-01

The NBSR is a 20 MW research reactor operated by the NIST Center for Neutron Research (NCNR) as a neutron source providing beams of thermal and cold neutrons for research in materials science, fundamental physics and nuclear chemistry. A large, 550 mm diameter beam port was included in the design for the installation of a cold neutron source, and the NCNR has been steadily improving its cold neutron facilities for more than 25 years. Monte Carlo Simulations have shown that a liquid deuterium (LD 2 ) source will provide a gain of 1.5 to 2 for neutron wavelengths between 4 A and 10 A with respect to the existing liquid hydrogen cold source. The conceptual design for the LD 2 source will be presented. To achieve these gains, a large volume (35 litres) of LD 2 is required. The expected nuclear heat load in this moderator and vessel is 4000 W. A new, 7 kW helium refrigerator is being built to provide the necessary cooling capacity; it will be completely installed and tested early in 2014. The source will operate as a naturally circulating thermosiphon, very similar to the horizontal cold source in the High Flux Reactor at the Institut Laue-Langevin (ILL) in Grenoble. A condenser will be mounted on the reactor face about 2 m above the source providing the gravitational head to supply the source with LD 2 . The system will always be open to a 16 m3 ballast tank to store the deuterium at 500 kPa when the refrigerator is not operating, and providing a passively safe response to a refrigerator trip. It is expected the source will operate at 23 K, the boiling point of LD 2 at 100 kPa. All components will be surrounded by a blanket of helium to prevent the possibility of creating a flammable mixture of deuterium and air. A design for the cryostat assembly, consisting of the moderator chamber, vacuum jacket, helium containment and a heavy water cooling water jacket, has been completed and sent to procurement to solicit bids. It is expected that installation of the LD 2 cold

A Liquid Deuterium Cold Neutron Source for the NIST Research Reactor - Conceptual Design

Energy Technology Data Exchange (ETDEWEB)

Williams, R. E.; Middleton, M.; Kopetka, P.; Rowe, J. M.; Brand, P. C. [NIST Center for Neutron Research, Gaithersburg (United States)

2013-07-01

The NBSR is a 20 MW research reactor operated by the NIST Center for Neutron Research (NCNR) as a neutron source providing beams of thermal and cold neutrons for research in materials science, fundamental physics and nuclear chemistry. A large, 550 mm diameter beam port was included in the design for the installation of a cold neutron source, and the NCNR has been steadily improving its cold neutron facilities for more than 25 years. Monte Carlo Simulations have shown that a liquid deuterium (LD{sub 2}) source will provide a gain of 1.5 to 2 for neutron wavelengths between 4 A and 10 A with respect to the existing liquid hydrogen cold source. The conceptual design for the LD{sub 2} source will be presented. To achieve these gains, a large volume (35 litres) of LD{sub 2} is required. The expected nuclear heat load in this moderator and vessel is 4000 W. A new, 7 kW helium refrigerator is being built to provide the necessary cooling capacity; it will be completely installed and tested early in 2014. The source will operate as a naturally circulating thermosiphon, very similar to the horizontal cold source in the High Flux Reactor at the Institut Laue-Langevin (ILL) in Grenoble. A condenser will be mounted on the reactor face about 2 m above the source providing the gravitational head to supply the source with LD{sub 2}. The system will always be open to a 16 m3 ballast tank to store the deuterium at 500 kPa when the refrigerator is not operating, and providing a passively safe response to a refrigerator trip. It is expected the source will operate at 23 K, the boiling point of LD{sub 2} at 100 kPa. All components will be surrounded by a blanket of helium to prevent the possibility of creating a flammable mixture of deuterium and air. A design for the cryostat assembly, consisting of the moderator chamber, vacuum jacket, helium containment and a heavy water cooling water jacket, has been completed and sent to procurement to solicit bids. It is expected that

Biosorption of aluminum on Pseudomonas aeruginosa loaded on Chromosorb 106 prior to its graphite furnace atomic absorption spectrometric determination

International Nuclear Information System (INIS)

Tuzen, Mustafa; Soylak, Mustafa

2008-01-01

A biosorption procedure for separation-enrichment of aluminum in environmental samples has been presented in this work. Pseudomonas aeruginosa loaded on Chromosorb 106 has been used as biosorbent for that purpose. P. aeruginosa is a gram-negative, aerobic rod. The influences of pH of the aqueous solution, eluent type, eluent volume, sample volume, etc. were examined on the quantitative recovery of aluminum in P. aeruginosa loaded on Chromosorb 106. The effects of concomitant ions on the recoveries of aluminum were also investigated. The detection limit based on 3 sigma for aluminum is 30 ng L -1 . Three certified reference materials (LGC 6010 Hard Drinking Water, NIST-SRM 1568a Rice Flour and NRCC-DORM-2 Dogfish Muscle) were analyzed for the validation of the presented procedure. The proposed procedure was applied to the determination of aluminum in environmental samples including natural water and food samples. The concentration of aluminum in real samples was found at ppb level

Penzijní připojištění: kteří občané se jej účastní nejvíce a platí nejvyšší příspěvky?

Czech Academy of Sciences Publication Activity Database

Janský, Petr

2015-01-01

Roč. 10, č. 3 (2015), s. 43-55 ISSN 1802-2200 Institutional support: RVO:67985998 Keywords : retirement savings * supplementary retirement savings * pension system Subject RIV: AH - Economics http://www.vse.cz/cfuc/449

Determination of Iodate in Food, Environmental, and Biological Samples after Solid-Phase Extraction with Ni-Al-Zr Ternary Layered Double Hydroxide as a Nanosorbent

Directory of Open Access Journals (Sweden)

Hossein Abdolmohammad-Zadeh

2012-01-01

Full Text Available Nanostructured nickel-aluminum-zirconium ternary layered double hydroxide was successfully applied as a solid-phase extraction sorbent for the separation and pre-concentration of trace levels of iodate in food, environmental and biological samples. An indirect method was used for monitoring of the extracted iodate ions. The method is based on the reaction of the iodate with iodide in acidic solution to produce iodine, which can be spectrophotometrically monitored at 352 nm. The absorbance is directly proportional to the concentration of iodate in the sample. The effect of several parameters such as pH, sample flow rate, amount of nanosorbent, elution conditions, sample volume, and coexisting ions on the recovery was investigated. In the optimum experimental conditions, the limit of detection (3s and enrichment factor were 0.12 μg mL−1 and 20, respectively. The calibration graph using the preconcentration system was linear in the range of 0.2–2.8 μg mL−1 with a correlation coefficient of 0.998. In order to validate the presented method, a certified reference material, NIST SRM 1549, was also analyzed.

Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

Science.gov (United States)

Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

2006-09-22

The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

Application of instrumental neutron activation analysis for the examination of oil pigments

Energy Technology Data Exchange (ETDEWEB)

Chung, Y.S.; Kim, S.H.; Sun, G.M.; Lim, J.M.; Moon, J.H.; Kim, Y.J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, S.J.; Song, Y.N.; Kim, K. [National Museum of Contemporary Art, Gwacheon, Gyeonggi-do (Korea, Republic of)

2011-07-01

This study is to investigate the applicability of instrumental neutron activation analysis (INAA) as a non-destructive examination tool for the quantitative chemical composition analysis associated with authentication, restoration and conservation of art objects in the field of cultural heritage. The quantitative analysis of major, minor and trace elements in Rembrandt's {sup registered} oil pigments recently collected at the Korean market as one of the art objects was carried out using INAA facilities of the HANARO research reactor at the Korea Atomic Energy Research Institute in collaboration with the National Museum of Contemporary Art in Korea. Analytical quality control was implemented using NIST SRM 2709, certified reference materials and metal standards. The analytical results for seventeen characteristic elements of thirty-one measured elements were statistically treated to identify the characteristic correlations and patterns between color and source of oil pigment and similarity degree of constituents using a cluster and discriminate analysis. (orig.)

Application of polyhydroxybutyrate-b-polyethyleneglycol (a block co-polymer) for solid phase extraction of lead and copper in different food samples

International Nuclear Information System (INIS)

Kazi, T.G.; Afridi, H.I.; Tuzen, M.; Naeemullah, A.

2014-01-01

In present work, a new adsorbent, polyhydroxybutyrate-b-polyethyleneglycol (block copolymer) was used for the preconcentration and separation of copper (Cu) and lead (Pb) ions without consuming expensive complexing reagent. The influence of various parameters like pH, adsorbent amount, and rates of flow of eluent, sample and sample volumes has been investigated. The polymer does not interact with alkaline earth metals, transition metals, alkaline, and few anions. The enrichment factor 50 was achieved in this method. The detection limit of method was found to be 0.36 micro g L/sup 1/ and 1.93 micro g L/sup 1/ for copper and lead, respectively. The recovery values of both analytes were found >96% and relative standard deviations (RSD) for all experiments were found less than 5%. The present method was validated by the analysis of Cu and Pb contents in various related certified reference materials (CRM) like; NIST SRM 1515 Apple leaves, IAEA -336 Lichen and GBW-07605 Tea. Found results and CRM values were precise and accurate. This developed method was then successfully applied for analysis of Cu and Pb in tap and bottled mineral water and real food samples. (author)

Cultivable microscopic fungi from an underground chemosynthesis-based ecosystem: a preliminary study

Czech Academy of Sciences Publication Activity Database

Nováková, Alena; Hubka, Vít; Valinová, Š.; Kolařík, Miroslav; Hillebrand-Voiculescu, A.M.

2018-01-01

Roč. 63, č. 1 (2018), s. 43-55 ISSN 0015-5632 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : MOVILE CAVE * GROUNDWATER ECOSYSTEM * MICROBIAL COMMUNITIES Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 1.521, year: 2016

INAA at the top of the world: Elemental characterization and analysis of airborne particulate matter collected in the Himalayas at 5,100 m high

International Nuclear Information System (INIS)

Giaveri, G.; Bergamaschi, L.; Rizzio, E.; Brandone, A.; Profumo, A.; Gallorini, M.; Zambelli, G.; Baudo, R.; Tartari, G.

2005-01-01

In 1990, following an agreement with the Royal Nepal Academy of Science, the Italian National Research Council (CNR) installed a scientific laboratory (Pyramid) at 5,050 m (s.l.) in the Himalayan region. Among the environmental related researches, the task project RATEAP (Remote Areas Trace Elements Atmospheric Pollution), started in 2001, aims at obtaining information about the chemical composition of the high altitude airborne particulate matter. During the period of March-April 2002 series of samplings have been carried out by pump aspiration. Samples of total suspended particles (TSP) as well as of the particles size fraction PM10 and PM 2.5 have been collected and submitted to INAA for the determination of more than 30 elements present, at nanogram levels, in few micrograms of air dust. Data quality assurance has been performed by the analysis of different NIST SRMs and, in particular, the SRM 2783 Air particulate on Filter Media. (author)

Methodology for determination of trace elements in mineral phases of iron banded formation by LA-ICP-MS; Metodologia de determinacao de elementos-traco em fases minerais de formacoes ferriferas bandadas por LA-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Sousa, Denise V.M. de; Nalini Junior, Herminio A.; Sampaio, Geraldo M.S.; Abreu, Adriana T. de; Lana, Cristiano de C., E-mail: deniseversiane2@yahoo.com.br, E-mail: nalini@degeo.ufop.br, E-mail: geraldomssampaio@gmail.com, E-mail: adrianatropia@gmail.com, E-mail: cristianodeclana@gmail.com [Universidade Federal de Ouro Preto (DEGEO/UFOP), Ouro Preto, MG (Brazil). Departamento de Geologia

2015-07-01

The study of the chemical composition of mineral phases of iron formation (FF), especially of trace elements, is an important tool in the understanding of the genesis of these rocks and the contribution of the phases in the composition of whole rock. Low mass fraction of such elements in the mineral phases present in this rock type requires a suitable analytical procedure. The laser ablation technique coupled with ICP-MS (LA-ICP-MS) has been widely used for determination of trace elements in geological samples. Thus, the aim of this study is to develop calibration curves for determination of trace elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in mineral phases of banded iron formations by LA-ICP-MS. Several certified reference materials (CRM) were used for calibrate the equipment. The analytical conditions were checked by CRM NIST SRM 614. The results were satisfactory, since the curves showed good linearity coefficients, good accuracy and precision of results. (author)

INAA Application for Trace Element Determination in Biological Reference Material

Science.gov (United States)

Atmodjo, D. P. D.; Kurniawati, S.; Lestiani, D. D.; Adventini, N.

2017-06-01

Trace element determination in biological samples is often used in the study of health and toxicology. Determination change to its essentiality and toxicity of trace element require an accurate determination method, which implies that a good Quality Control (QC) procedure should be performed. In this study, QC for trace element determination in biological samples was applied by analyzing the Standard Reference Material (SRM) Bovine muscle 8414 NIST using Instrumental Neutron Activation Analysis (INAA). Three selected trace element such as Fe, Zn, and Se were determined. Accuracy of the elements showed as %recovery and precision as %coefficient of variance (%CV). The result showed that %recovery of Fe, Zn, and Se were in the range between 99.4-107%, 92.7-103%, and 91.9-112%, respectively, whereas %CV were 2.92, 3.70, and 5.37%, respectively. These results showed that INAA method is precise and accurate for trace element determination in biological matrices.

Methodology for determination of trace elements in mineral phases of iron banded formation by LA-ICP-MS

International Nuclear Information System (INIS)

Sousa, Denise V.M. de; Nalini Junior, Herminio A.; Sampaio, Geraldo M.S.; Abreu, Adriana T. de; Lana, Cristiano de C.

2015-01-01

The study of the chemical composition of mineral phases of iron formation (FF), especially of trace elements, is an important tool in the understanding of the genesis of these rocks and the contribution of the phases in the composition of whole rock. Low mass fraction of such elements in the mineral phases present in this rock type requires a suitable analytical procedure. The laser ablation technique coupled with ICP-MS (LA-ICP-MS) has been widely used for determination of trace elements in geological samples. Thus, the aim of this study is to develop calibration curves for determination of trace elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in mineral phases of banded iron formations by LA-ICP-MS. Several certified reference materials (CRM) were used for calibrate the equipment. The analytical conditions were checked by CRM NIST SRM 614. The results were satisfactory, since the curves showed good linearity coefficients, good accuracy and precision of results. (author)

Environmental application of XRF, ICP-AES and INAA on biological matrix

International Nuclear Information System (INIS)

Zararsiz, A.; Dogangun, A.; Tuncel, S.

2004-01-01

Full text: It is very important to determine trace quantities of metals in different matrices with high accuracy since the metals are used as markers for different sources in air pollution studies. In this study, the analytical capabilities of XRF, ICP-AES and INM techniques on a biological matrix namely lichens, which are widely used as bio monitoring organisms for the pollutants mapping in the atmosphere, were tested. Lichen samples were collected in Aegean Region of Turkey where pollution is an important issue. 9 elements were determined by XRF, 14 elements by ICP-AES and 13 elements by INM. Quality assurance was achieved using lichen SRM (IAEA-336) and Orchard leaves SRM (NIST- 1571). Produced data are subjected to statistical tests, like t-test, Q-test in order to determine the accuracy and precision of each technique. A recommendation list of the proper analytical technique is obtained for determination of each specific element considering analytical capabilities of ICP-AES, XRF and INM. As a result we can recommend that the first choice for Cd, Cu, Mg is ICP-AES, for In, K, Rb is INAA, for Br is XRF, if the concentrations are not close to the detection limit of XRF. For V, Cr, AI, Na, Fe ICP-AES and INM are both well, for Pb ICP-AES and XRF are both well, if the concentrations are not close to the detection limit of XRF, for Mn and Ca INM, XRF and ICP-AES are all give similar results for this type of biological matrix

Total sulfur determination in gasoline, kerosene and diesel fuel using inductively coupled plasma optical emission spectrometry after direct sample introduction as detergent emulsions

International Nuclear Information System (INIS)

Santelli, Ricardo Erthal; Padua Oliveira, Eliane; Batista de Carvalho, Maria de Fatima; Almeida Bezerra, Marcos; Soares Freire, Aline

2008-01-01

Herein, we present the development of a procedure for the determination of total sulfur in petroleum-derived products (gasoline, kerosene and diesel fuel) employing inductively coupled plasma optical emission spectrometry (ICP OES). For this procedure, samples were prepared as emulsions that were made using concentrated nitric acid, Triton X-100, sample, and ultra pure water in proportions of 5/10/7/78% (v/v), respectively. Sample volumes were weighed because of the density differences, and oxygen was added to the sheat gas entrance of the ICP OES in order to decrease carbon deposition in the torch and to minimize background effects. A Doehlert design was applied as an experimental matrix to investigate the flow ratios of argon (sheat and plasma gas) and oxygen in relation to the signal-to-background ratio. A comparative study among the slopes of the analytical curves built in aqueous media, surfactant/HNO 3 , and by spike addition for several sample emulsions indicates that a unique solution of surfactant in acidic media can be employed to perform the external calibration for analysis of the emulsions. The developed procedure allows for the determination of the total sulfur content in petroleum derivatives with a limit of detection (LOD) and limit of quantification (LOQ) of 0.72 and 2.4 μg g -1 , respectively. Precision values, expressed as the relative standard deviations (% RSD, n = 10) for 12 and 400 μg g -1 , were 2.2% and 1.3%, respectively. The proposed procedure was applied toward the determination of total sulfur in samples of gasoline, kerosene, and diesel fuel commercialized in the city of Niteroi/RJ, Brazil. The accuracy of the proposed method was evaluated by the determination of the total sulfur in three different standard reference materials (SRM): NIST 2723a (sulfur in diesel fuel oil), NIST 1616b (sulfur in kerosene), and NIST 2298 (sulfur in gasoline). The data indicate that the methodology can be successfully applied to these types of samples

Simultaneous determination of V, As, Se, Cd, Ba and Pb in coal by ICP-MS after high pressure oxygen combustion

Energy Technology Data Exchange (ETDEWEB)

Akiyama, K.; Arikawa, Y. [Japan Womens University, Tokyo (Japan). Graduate School of Science

2007-04-15

A simple decomposition procedure by a high pressure oxygen combustion method was employed for the determination of six elements (V, As, Se, Cd, Ba and Pb) in coal by inductively coupled plasma mass spectrometry (ICP-MS). Combustion under 3 MPa pressure of oxygen in a sealed bomb is a simple and effective method for the decomposition of carbonaceous materials. Organic components are burnt to form CO{sub 2} and H{sub 2}O. Other components also form oxides, which are absorbed in the absorbing solution of a 5 mL of 5% HNO{sub 3} - 1% H{sub 2}O1 Mixed solution put in a bomb. To completely decompose the sample, 600 mg of starch is added to 300 mg of a ground coal sample. Though ignition normally takes about s, 30 min is required before opening the bomb to keep to the oxides absorbed into the absorbing solution. The accuracy of the procedure was evaluated by comparing the determination value of each element with a certified value of a standard reference material. In this study, NIST SRM 1632c and 1632b, given by the National Institute for Standards and Technology in Washington DC, USA were used as standard reference materials. The results obtained by ICP-MS after high pressure oxygen combustion showed good agreements with the certified values of NIST 1632c for 6 elements (V, As, Se, Cd, Ba, Pb). This method was applied to the determination of 6 elements in coal real samples supplied by CCUJ (Center of Coal Utilization Japan).

Sustained release of a novel anti-quorum-sensing agent against oral fungal biofilms.

Science.gov (United States)

Feldman, Mark; Shenderovich, Julia; Al-Quntar, Abed Al Aziz; Friedman, Michael; Steinberg, Doron

2015-04-01

Thiazolidinedione-8 (S-8) has recently been identified as a potential anti-quorum-sensing/antibiofilm agent against bacteria and fungi. Based on these results, we investigated the possibility of incorporating S-8 in a sustained-release membrane (SRM) to increase its pharmaceutical potential against Candida albicans biofilm. We demonstrated that SRM containing S-8 inhibits fungal biofilm formation in a time-dependent manner for 72 h, due to prolonged release of S-8. Moreover, the SRM effectively delivered the agent in its active form to locations outside the membrane reservoir. In addition, eradication of mature biofilm by the SRM containing S-8 was also significant. Of note, S-8-containing SRM affected the characteristics of mature C. albicans biofilm, such as thickness, exopolysaccharide (EPS) production, and morphogenesis of fungal cells. The concept of using an antibiofilm agent with no antifungal activity incorporated into a sustained-release delivery system is new in medicine and dentistry. This concept of an SRM containing a quorum-sensing quencher with an antibiofilm effect could pave the way for combating oral fungal infectious diseases. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Analytical quality control of neutron activation analysis by interlaboratory comparison and proficiency test

International Nuclear Information System (INIS)

Kim, S. H.; Moon, J. H.; Jeong, Y. S.

2002-01-01

Two air filters (V-50, P-50) artificially loaded with urban dust were provided from IAEA and trace elements to study inter-laboratory comparison and proficiency test were determined using instrumental neutron activation analysis non-destructively. Standard reference material(Urban Particulate Matter, NIST SRM 1648) of National Institute of Standard and Technology was used for internal analytical quality control. About 20 elements in each loaded filter sample were determined, respectively. Our analytical data were compared with statistical results using neutron activation analysis, particle induced X-ray emission spectrometry, inductively coupled plasma mass spectroscopy, etc., which were collected from 49 laboratories of 40 countries. From the results that were statistically re-treated with reported values, Z-scores of our analytical values are within ±2. In addition, the results of proficiency test are passed and accuracy and precision of the analytical values are reliable. Consequently, it was proved that analytical quality control for the analysis of air dust samples is reasonable

Rapid determination of silver in cultivated Japanese and South Korean oysters and Japanese rock oysters using the 24.6-s neutron activation product 110Ag and estimation of its average daily intake

International Nuclear Information System (INIS)

Fukushima, M.; Chatt, A.

2013-01-01

Soft tissues of cultivated Japanese (Miyagi Prefecture) and South Korean (Koje-do and Kosong) oysters and Japanese rock oysters (Honshu Island) were analyzed to measure silver levels. The soft tissues, namely hepatopancreas, gill, muscle, and mantle were separated, freeze-dried, pulverized, and analyzed by an instrumental neutron activation analysis method in conjunction with Compton suppression spectrometry (INAA-CSS). The method consisted of the irradiation of samples in a neutron flux of 5 x 10 11 cm -2 s -1 using the rapid transfer system in an inner pneumatic irradiation site of the Dalhousie University SLOWPOKE-2 reactor (DUSR) facility for 12-15 s, decay for 20 s, and counting for 60 s. The 657.8-keV gamma-ray of the 24.6-s nuclide 110 Ag was used for assaying silver. The method was validated using NIST, NRC and NIES certified reference materials. An absolute detection limit of 0.05 μg silver using NIST SRM 1566b Oyster Tissue was achieved. About 10-50 times higher levels of silver were found in cultivated Japanese oysters compared to the South Korean ones. The silver concentrations in cultivated oysters in Miyagi Prefecture showed the following trend: gill > mantle > hepatopancreas > muscle as well as on the age. Rock oysters generally had higher silver content compared to cultivated oysters. A very preliminary value of about 0.466 μg silver average intake per person per day was estimated from the consumption of oysters by the people living in the Sendai city of Miyagi Prefecture. (author)

CDC28, NETI, and HFII are required for checkpoints in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Koltovaya, N.A.; Kadyshevskaya, E.Yu.; Roshina, M.P.; Devin, A.B.

2009-01-01

The involvement of SRM genes selected as genes affecting genetic stability and radiosensitivity in a cell cycle arrest under the action of damaging agents was studied. It was shown that the srm5/cdc28-srm, srm8/netI-srm, and srmI2/hfiI-srm mutations prevent checkpoint activation by DNA damage, particularly the G 0 /S (srm5, srm8), G 1 /S (srm5, srm8, srm12), S (srm8, srm12) and S/G 2 (srm5) checkpoints. It seems that in budding yeast the CDC28, HFII/ADAI, and NETI genes mediate cellular response induced by DNA damage with checkpoint control. The well-known checkpoint-genes RAD9, RAD17, RAD24, and RAD53, and the genes CDC28, and NETI have been found to belong to one epistasis group named RAD9-group as regards cell sensitivity to γ radiation. An analysis of the radiosensitivity of double mutants has revealed that the mutation cdc-28-srm is hypostatic to each of mutations rad9Δ, and rad24Δ, and additive to rad17Δ. The mutation netI-srm is hypostatic to the mutations rad9Δ but additive to rad17Δ, rad24Δ, and rad53. The mutation hfiI-srm has an additive effect in compound with the mutations rad24Δ and rad9Δ. So, investigations of epistatic interactions have demonstrated a branched RAD9-dependent pathway. The analyzed genes can also participate in a minor mechanism involved in determining cell radiation sensitivity independently of the mentioned RAD9-dependent pathway

A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry.

Science.gov (United States)

Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S; Korn, Maria G A; Bezerra, Marcos A

2009-03-15

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.

A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S.; Korn, Maria G.A.; Bezerra, Marcos A.

2009-01-01

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L -1 nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 μg L -1 , respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 μg L -1 . The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish

76 FR 22308 - Airworthiness Directives; Airbus Model A340-541 and -642 Airplanes

Science.gov (United States)

2011-04-21

...: * * * * * * * * [S]ome Allowable Damage Limits and Repairs published in SRM Chapters 57-61-12 PB101 and 57-61-12...-validated SRM'' used in this AD text refers to the SRM chapters mentioned above. In order to prevent... strength re- valuation, some Allowable Damage Limits (ADL) and Repairs of holes and delaminations in...

Determination of parent and hydroxy PAHs in personal PM{sub 2.5} and urine samples collected during Native American fish smoking activities

Energy Technology Data Exchange (ETDEWEB)

Motorykin, Oleksii [Department of Chemistry, Oregon State University, Corvallis, OR 97331 (United States); Schrlau, Jill; Jia, Yuling [Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States); Harper, Barbara; Harris, Stuart [Department of Science and Engineering, Confederated Tribes of the Umatilla Indian Reservation, Pendleton, OR 97801 (United States); Harding, Anna [School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 (United States); Stone, David [Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States); Kile, Molly [School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331 (United States); Sudakin, Daniel [Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States); Massey Simonich, Staci L., E-mail: staci.simonich@orst.edu [Department of Chemistry, Oregon State University, Corvallis, OR 97331 (United States); Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States)

2015-02-01

A method was developed for the measurement of 19 parent PAHs (PAHs) and 34 hydroxylated PAHs (OH-PAHs) in urine and personal air samples of particulate matter less than 2.5 μm in diameter (PM{sub 2.5}) using GC–MS and validated using NIST SRM 3672 (Organic Contaminants in Smoker's Urine) and SRM 3673 (Organic Contaminants in Nonsmoker's Urine). The method was used to measure PAHs and OH-PAHs in urine and personal PM{sub 2.5} samples collected from the operators of two different fish smoking facilities (tipi and smoke shed) burning two different wood types (alder and apple) on the Confederated Tribes of Umatilla Indian Reservation (CTUIR) while they smoked salmon. Urine samples were spiked with β-glucuronidase/arylsulfatase to hydrolyze the conjugates of OH-PAHs and the PAHs and OH-PAHs were extracted using Plexa and C18 solid phases, in series. The 34 OH-PAHs were derivatized using MTBSTFA, and the mixture was measured by GC–MS. The personal PM{sub 2.5} samples were extracted using pressurized liquid extraction, derivatized with MTBSTFA and analyzed by GC–MS for PAHs and OH-PAHs. Fourteen isotopically labeled surrogates were added to accurately quantify PAHs and OH-PAHs in the urine and PM{sub 2.5} samples and three isotopically labeled internal standards were used to calculate the recovery of the surrogates. Estimated detection limits in urine ranged from 6.0 to 181 pg/ml for OH-PAHs and from 3.0 to 90 pg/ml for PAHs, and, in PM{sub 2.5}, they ranged from 5.2 to 155 pg/m{sup 3} for OH-PAHs and from 2.5 to 77 pg/m{sup 3} for PAHs. The results showed an increase in OH-PAH concentrations in urine after 6 h of fish smoking and an increase in PAH concentrations in air within each smoking facility. In general, the PAH exposure in the smoke shed was higher than in the tipi and the PAH exposure from burning apple wood was higher than burning alder. - Highlights: • An analytical method was developed for the measurement of 19 PAHs and 34 OH-PAHs. �

Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Shaheen, M.E., E-mail: mshaheen73@science.tanta.edu.eg [Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J.E.; Fryer, B.J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2015-05-01

Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using {sup 66}Zn/{sup 63}Cu, {sup 208}Pb/{sup 238}U, {sup 232}Th/{sup 238}U, {sup 66}Zn/{sup 232}Th and {sup 66}Zn/{sup 208}Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to

Trace elements in landfill calcite: a comparison of solution & laser ablation ICP-MS and calibration to different standard material (SRM NIST glass and USGS MACS carbonate)

Czech Academy of Sciences Publication Activity Database

Strnad, L.; Ettler, V.; Mihaljevič, M.; Hladil, Jindřich

2008-01-01

Roč. 9, - (2008), s. 235-236 ISSN 1885-7264. [Reunión de la Sociedad Española de Mineralogía /28./ ; Reunión de la Sociedad Española de Arcillas /21./. Zaragoza, 16.09.2008-19.09.2008] R&D Projects: GA AV ČR IAA300130702 Institutional research plan: CEZ:AV0Z30130516 Keywords : trace elements * reference material * carbonate * ICP-MS * laser ablation Subject RIV: DB - Geology ; Mineralogy http://www.ehu.es/sem/macla_pdf/macla9/macla9_235.pdf

A biosorption system for metal ions on Penicillium italicum - loaded on Sepabeads SP 70 prior to flame atomic absorption spectrometric determinations

International Nuclear Information System (INIS)

Mendil, Durali; Tuzen, Mustafa; Soylak, Mustafa

2008-01-01

A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the μg L -1 levels on Penicillium italicum - loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L -1 HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3 s, n = 21) for analytes were in the range of 0.41 μg L -1 (cadmium) and 1.60 μg L -1 (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples

A biosorption system for metal ions on Penicillium italicum - loaded on Sepabeads SP 70 prior to flame atomic absorption spectrometric determinations

Energy Technology Data Exchange (ETDEWEB)

Mendil, Durali; Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Science and Arts, Chemistry Department, 38039 Kayseri (Turkey)], E-mail: msoylak@gmail.com

2008-04-15

A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the {mu}g L{sup -1} levels on Penicillium italicum - loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L{sup -1} HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3 s, n = 21) for analytes were in the range of 0.41 {mu}g L{sup -1} (cadmium) and 1.60 {mu}g L{sup -1} (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples.

NBS activities in biological reference materials

Energy Technology Data Exchange (ETDEWEB)

Rasberry, S.D.

1988-12-01

NBS activities in biological reference materials during 1986-1988 are described with a preview of plans for future certifications of reference materials. During the period, work has been completed or partially completed on about 40 reference materials of importance to health, nutrition, and environmental quality. Some of the reference materials that have been completed during the period and are described include: creatinine (SRM 914a), bovine serum albumin (SRM 927a), cholesterol in human serum (SRM's 1951-1952), aspartate aminotransferase (RM 8430), cholesterol and fat-soluble vitamins in coconut oil (SRM 1563), wheat flour (SRM 1567a), rice flour (SRM 1568a), mixed diet (RM 8431a), dinitropyrene isomers and 1-nitropyrene (SRM 1596), and complex PAH's from coal tar (SRM 1597). Oyster tissue (SRM 1566a) is being analyzed and should be available in 1988.

Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition

Science.gov (United States)

Pribil, M.J.; Wanty, R.B.; Ridley, W.I.; Borrok, D.M.

2010-01-01

An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations in acid mine drainage (AMD) can range from 100??g/L to greater than 50mg/L with sulfur species concentrations reaching greater than 1000mg/L. Routine separation of Cu, Fe and Zn from AMD, Cu-sulfide minerals and other geological matrices usually incorporates single anion exchange resin column chromatography for metal separation. During chromatographic separation, variable breakthrough of SO42- during anion exchange resin column chromatography into the Cu fractions was observed as a function of the initial sulfur to Cu ratio, column properties, and the sample matrix. SO42- present in the Cu fraction can form a polyatomic 32S-14N-16O-1H species causing a direct mass interference with 63Cu and producing artificially light ??65Cu values. Here we report the extent of the mass interference caused by SO42- breakthrough when measuring ??65Cu on natural samples and NIST SRM 976 Cu isotope spiked with SO42- after both single anion column chromatography and double anion column chromatography. A set of five 100??g/L Cu SRM 976 samples spiked with 500mg/L SO42- resulted in an average ??65Cu of -3.50?????5.42??? following single anion column separation with variable SO42- breakthrough but an average concentration of 770??g/L. Following double anion column separation, the average SO42-concentration of 13??g/L resulted in better precision and accuracy for the measured ??65Cu value of 0.01?????0.02??? relative to the expected 0??? for SRM 976. We conclude that attention to SO42- breakthrough on sulfur-rich samples is necessary for accurate and precise measurements of ??65Cu and may require

Determination of selenium in roasted beans coffee samples consumed in Algeria by radiochemical neutron activation analysis method

International Nuclear Information System (INIS)

Messaoudi, Mohammed; Begaa, Samir; Hamidatou, Lylia; Salhi, M'hamed

2018-01-01

The essential trace element selenium is a focus of attention due to its effects on human health, there being consequences of both its deficiency and excess. Due to the ultra-trace content of selenium, the neutron activation analysis method (NAA) is difficult to apply. We therefore made use of the radiochemical neutron activation analysis (RNAA) to determine Se at low level concentrations in several consumed food items in Algeria. A radiochemical procedure based on liquid-liquid separation was established in our laboratory. In this research we focused on the determination of selenium in two species of coffee: Arabica and Robusta. The accuracy of the method was assessed by analyzing the certified reference material NIST-SRM 1573a (tomato leaves). The results obtained show a selenium variation from 0.025 to 0.052 μg/g in coffee beans and an average yield of the separation of about 85%. The results of this study were compared with those obtained with samples from Brazilian, Caribbean, Indian and Kenyan coffee beans.

Application of Solid Phase Extraction on Multiwalled Carbon Nanotubes of Some Heavy Metal Ions to Analysis of Skin Whitening Cosmetics Using ICP-AES

Directory of Open Access Journals (Sweden)

Kamal Omer

2013-01-01

Full Text Available A novel and highly sensitive method for the determination of some heavy metals in skin whitening cosmetics creams using multiwalled carbon nanotubes MWCNTs as solid phase extraction sorbent for the preconcentration of these heavy metals prior to their determination by inductively coupled plasma atomic emission spectrometry is described. Different practical parameters have been thoroughly investigated and the optimum experimental conditions were employed. The developed method was then applied for the determination of arsenic, bismuth, cadmium, mercury, lead and titanium in samples of skin whitening cosmetics. The detection limits under these conditions for As, Bi, Cd, Pb, Hg and Ti were 2.4, 4.08, 0.3, 2.1, 1.8, and 1.8 ng·mL−1, respectively. The relative standard deviations (RSDs were found to be less than 2.0%. For validation, a certified reference material of NIST SRM 1570a spinach leaves was analyzed and the determined values were in good agreement with the certified values. The recoveries for spiked samples were found to be in the range of 89.6–104.4%.

Application of solid phase extraction on multiwalled carbon nanotubes of some heavy metal ions to analysis of skin whitening cosmetics using ICP-AES.

Science.gov (United States)

Alqadami, Ayoub A; Abdalla, Mohammad Abulhassan; AlOthman, Zeid A; Omer, Kamal

2013-01-14

A novel and highly sensitive method for the determination of some heavy metals in skin whitening cosmetics creams using multiwalled carbon nanotubes MWCNTs as solid phase extraction sorbent for the preconcentration of these heavy metals prior to their determination by inductively coupled plasma atomic emission spectrometry is described. Different practical parameters have been thoroughly investigated and the optimum experimental conditions were employed. The developed method was then applied for the determination of arsenic, bismuth, cadmium, mercury, lead and titanium in samples of skin whitening cosmetics. The detection limits under these conditions for As, Bi, Cd, Pb, Hg and Ti were 2.4, 4.08, 0.3, 2.1, 1.8, and 1.8 ng·mL-1, respectively. The relative standard deviations (RSDs) were found to be less than 2.0%. For validation, a certified reference material of NIST SRM 1570a spinach leaves was analyzed and the determined values were in good agreement with the certified values. The recoveries for spiked samples were found to be in the range of 89.6-104.4%.

Nonlinear Deadbeat Current Control of a Switched Reluctance Motor

OpenAIRE

Rudolph, Benjamin

2009-01-01

High performance current control is critical to the success of the switched reluctance motor (SRM). Yet high motor phase nonlinearities in the SRM place extra burden on the current controller, rendering it the weakest link in SRM control. In contrast to linear motor control techniques that respond to current error, the deadbeat controller calculates the control voltage by the current command, phase current, rotor position and applied phase voltage. The deadbeat controller has demonstrated sup...

Monitoring environmental pollution by ko-INAA for environmental protection in Indonesia

International Nuclear Information System (INIS)

Sutisna; Saryati; Yusuf, Saeful; Rina, Theresia; Suryani, Rina

2007-01-01

Regarding to the 2005-2007FNCA program decided, the NAA technique based on the k o -method has been used to determine a concentration of pollutant as function of time and location. This program carries out to monitor a pollutant in the marine environmental sample. Marine samples of sediment, seawater and a clamp, as well as, a green oyster collected from a selected location at north of Banten province and the Bay of Jakarta. Sampling have been carried out twice a year. For background, same sample have been collected at the sampling point located at south-west of Banten. Sediment and biota sample were prepared for NAA determination, meanwhile seawater have been prepared for polarographic measurement. Marine Sediment and biota samples, as well as flux monitor, have been irradiated at a rabbit system facility of RSG GA Siwabessy reactor with a thermal neutron flux of about 2.6.10 +17 n.m -2 .s -1 . Identification of (n, γ) reaction product has been done using a high resolution HPGe detector coupled to a multichannel analyzer. Analysis of γ-ray emitted by activation product have been done using Hyperlab software, while the elemental quantitative analysis have been done by the k o -INAA procedure using k o -IAEA software. The analytical quality was controlled by use of certified reference material of NIST 2702 Marine Sediment, SRM NIST 1566b Oyster Tissue, crm NMIJ 7302a Sediment and CRM No. 9 Sargasso. As preliminary result, the numbers of interested elements in sediments samples were determined to be of about 20 and should be presented in this workshop. Some results of k o -INAA assessment will also be reported and discussed. (author)

PIXE analysis of cancer-afflicted human bladder

Energy Technology Data Exchange (ETDEWEB)

Raju, G.J. Naga; Sarita, P.; Kumar, M. Ravi [Department of Physics, Institute of Technology, GITAM University, Visakhapatnam (India); Reddy, S. Bhuloka [Swami Jnanananda Laboratories for Nuclear Research, Andhra University, Visakhapatnam (India)

2013-07-01

Full text: The proton induced x-ray emission (PIXE) technique was used for analysis of trace elements in small quantities of biological samples. Both the biological samples of normal and cancer-afflicted human bladder tissues were studied. The present experiment was performed using a 3 MV pelletron accelerator at the Institute of Physics in Bhubaneswar, India. A proton beam of 3 MeV energy was used to excite the samples. NIST SRM 1577b Bovine Liver Tissue was used as external standards for the determination of trace element concentration in the biological tissue samples. The elements CI, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, and Se were identified and their concentrations were estimated. The concentrations of Ti and Zn are lower (p < 0.005) and that of Cr, Mn, Fe, Ni, and Cu are significantly higher (p < 0.001) in cancerous tissues than that in normal tissues. The deficiency or excess of different trace elements observed in the cancer tissues relative to the normal tissues of bladder are correlated to the pathology of cancer. (author)

Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

Science.gov (United States)

Tuzen, Mustafa; Pekiner, Ozlem Zeynep

2015-12-01

A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accurate Determination of Platinum, Palladium, and Rhodium in Ryegrass using Collision Cell Inductively Coupled Plasma Mass Spectrometry with Xenon as Collision Gas

International Nuclear Information System (INIS)

Amr, M.A.

2011-01-01

Inductively coupled plasma mass spectrometry with an octupole collision cell was used for determination of Pt, Pd and Rh in ryegrass (Lolium multiflorum) which was grown hydroponically. Xenon was used as a collision gas to reduce serious polyatomic interferences formed by combination of matrix elements such as CI, Cu, Hf, Sr, Zn, Zr, Y and REE with O, N, C, and Ar. The detection limits for Pt, Pd and Rh in spiked ryegrass are 1.8, 4.2, and 0.8 ppt, respectively. The results for Pt, Pd and Rh in reference materials (NIST SRM 2557, recycled monolith auto catalyst) are in agreement with the certified values. The bioaccumulation of Pt, Pd and Rh by ryegrass grown hydroponically with nutrient solutions containing Pt, Pd and Rh was studied. The obtained results showed that most of the studied metals were accumulated in roots, and only a small fraction was metabolized and transported to leaves. The highest bioaccumulation factors were obtained for Pd and Rh in roots and for Pt in leaves

Integration of aspect and slope in snowmelt runoff modeling in a mountain watershed

Directory of Open Access Journals (Sweden)

Shalamu Abudu

2016-10-01

Full Text Available This study assessed the performances of the traditional temperature-index snowmelt runoff model (SRM and an SRM model with a finer zonation based on aspect and slope (SRM + AS model in a data-scarce mountain watershed in the Urumqi River Basin, in Northwest China. The proposed SRM + AS model was used to estimate the melt rate with the degree-day factor (DDF through the division of watershed elevation zones based on aspect and slope. The simulation results of the SRM + AS model were compared with those of the traditional SRM model to identify the improvements of the SRM + AS model's performance with consideration of topographic features of the watershed. The results show that the performance of the SRM + AS model has improved slightly compared to that of the SRM model. The coefficients of determination increased from 0.73, 0.69, and 0.79 with the SRM model to 0.76, 0.76, and 0.81 with the SRM + AS model during the simulation and validation periods in 2005, 2006, and 2007, respectively. The proposed SRM + AS model that considers aspect and slope can improve the accuracy of snowmelt runoff simulation compared to the traditional SRM model in mountain watersheds in arid regions by proper parameterization, careful input data selection, and data preparation.

Halloysite nanotubes as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction for the determination of bismuth in water samples using high-resolution continuum source graphite-furnace atomic absorption spectrometry

Science.gov (United States)

Krawczyk-Coda, Magdalena

2017-03-01

In this research, a simple, accurate, and inexpensive preconcentration procedure was developed for the determination of bismuth in water samples, using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). During the preconcentration step, halloysite nanotubes (HNTs) were used as a solid sorbent in ultrasound-assisted dispersive micro solid-phase extraction (USA DMSPE). The influence of the pH of the sample solution, amount of HNTs, and extraction time, as well as of the main parameters of HR CS GFAAS, on absorbance was investigated. The limit of detection was 0.005 μg L- 1. The preconcentration factor achieved for bismuth was 32. The relative standard deviation (RSD) was 4%. The accuracy of this method was validated by analyses of NIST SRM 1643e (Trace elements in water) and TMDA-54.5 (A high level fortified sample for trace elements) certified reference materials. The measured bismuth contents in these certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The proposed method has been successfully applied to the determination of bismuth in five different real water samples (seawater, lake water, river water, stream water and rain water).

77 FR 2548 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): Grants for...

Science.gov (United States)

2012-01-18

... 21-22, 2012 (Closed). Place: Crowne Plaza Atlanta Perimeter Hotel at Ravinia, 4355 Ashford Dunwoody... Determination of the Director, Management Analysis and Services Office, CDC, pursuant to Public Law 92-463...

77 FR 2549 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): Grants for...

Science.gov (United States)

2012-01-18

... 21-22, 2012 (Closed). Place: Crowne Plaza Atlanta Perimeter Hotel at Ravinia, 4355 Ashford Dunwoody... Determination of the Director, Management Analysis and Services Office, CDC, pursuant to Public Law 92-463...

A case study of multi-seam coal mine entry stability analysis with strength reduction method.

Science.gov (United States)

Tulu, Ihsan Berk; Esterhuizen, Gabriel S; Klemetti, Ted; Murphy, Michael M; Sumner, James; Sloan, Michael

2016-03-01

In this paper, the advantage of using numerical models with the strength reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under variable topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.

Determination of concentrations of chromium and other elements in soil and plant samples from leather tanning area by Instrumental Neutron Activation Analysis

International Nuclear Information System (INIS)

Rohit Kumar; Rai, A.K.; Alamelu, D.; Acharya, R.

2014-01-01

Chromium, one of the toxic elements, along with other elements has been determined in samples of soil and plant (leaves and seeds) from Jajmau Area, Kanpur district, India, which is irrigated with effluent waste water from leather tanning industries. Soil and plant samples were collected from these areas and analyzed by Instrumental Neutron Activation Analysis (INAA) using high flux reactor neutrons and high resolution gamma-ray spectrometry. Concentrations of fifteen elements in soil and five elements in plant samples were determined by relative method. Chromium concentrations were found to be in range of 45-3,900 mg kg -1 in soil samples and 14-83 mg kg -1 in plant samples. This study showed that Cr is present in significant amounts, in the soil as well as in the plant samples, near to the leather tanning area. As a part of quality control work, IAEA reference material (RM) SL-3 and NIST standard reference material (SRM) 1645 were analyzed and the quality of the results has been evaluated by calculating % deviations from recommended/literature/certified values. (author)

Characterisation of some exotic fruits (Morus nigra, Morus alba, Salvadora persica and Carissa opaca) used as herbal medicines by neutron activation analysis and estimation of their nutritional value

International Nuclear Information System (INIS)

Mohammad Wasim; Muhammad Daud; Mohammad Arif; Sajid Iqbal; Yasir Anwar

2012-01-01

In the under developed countries, the people of far-flung rural areas still depend to a large extent upon herbal medicines. At the foundation of usage of herbal medicine is the experience of thousands of years. The present paper deals with the characterisation of exotic fruits for essential and toxic elements. The samples include Morus nigra, Morus alba, Salvadora persica and Carissa opaca (from low and high altitude). Two standardizations of neutron activation analysis, that is, semi-absolute k 0-instrumental neutron activation analysis (k 0 -INAA) and epithermal neutron activation analysis (ENAA) were employed for the quantification of elements. The analysis methodologies were validated by analyzing the IAEA-336 (lichen) and NIST-SRM-1572 (citrus leaves). Sixteen elements including Br, Ca, Cl, Co, Cr, Fe, I, K, Mg, Mn, Na, Rb, Sb, Sc Sr, and Zn were determined in all samples. Daily intakes of various elements from the samples were measured and compared with the dietary reference intakes. Additionally, principal component analysis was performed to extract information regarding samples and elements. (author)

Forensic discrimination of aluminum foil by SR-XRF and ICP-AES

International Nuclear Information System (INIS)

Kasamatsu, Masaaki; Suzuki, Yasuhiro; Suzuki, Shinichi; Miyamoto, Naoki; Watanabe, Seiya; Shimoda, Osamu; Takatsu, Masahisa; Nakanishi, Toshio

2010-01-01

The application of synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) was investigated for the forensic discrimination of aluminum foil by comparisons of the elemental components. Small fragments (1 x 1 mm) were taken from 4 kinds of aluminum foils produced by different manufactures and used for measurements of the XRF spectrum at BL37XU of SPring-8. A comparison of the XRF spectra was effective for the discrimination of aluminum foils from different sources, because significant differences were observed in the X-ray peak intensities of Fe, Cu, Zn, Ga, Zr and Sn. These elements, except for Zr and Sn in the aluminum foils and NIST SRM1258 (Aluminium Alloy 6011), were also determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The observed values of Fe, Cu, Zn and Ga in NIST standard samples by ICP-AES showed satisfactorily good agreements with the certified or information values with relative standard deviations from 1.1% for Zn to 6.7% for Ga. The observed values for the aluminum foils by ICP-AES were compared with those by SR-XRF. Correlation coefficients from 0.997 for Cu/Fe to 0.999 for Zn/Fe and Ga/Fe were obtained between the ratio of the elemental concentration by ICP-AES and normalized the X-ray intensity by SR-XRF. This result demonstrates that a comparison of the normalized X-ray intensity is nearly as effective for the discrimination of aluminum foils as quantitative analysis by ICP-AES. Comparisons of the analytical results by SR-XRF allow the discrimination of all aluminum foils using only a 1 mm 2 fragment with no destruction of the samples. (author)

Tailoring NIST Security Controls for the Ground System: Selection and Implementation -- Recommendations for Information System Owners

Science.gov (United States)

Takamura, Eduardo; Mangum, Kevin

2016-01-01

. Certain protective measures for the general enterprise may not be as efficient within the ground segment. This is what the authors have concluded through observations and analysis of patterns identified from the various security assessments performed on NASA missions such as MAVEN, OSIRIS-REx, New Horizons and TESS, to name a few. The security audits confirmed that the framework for managing information system security developed by the National Institute of Standards and Technology (NIST) for the federal government, and adopted by NASA, is indeed effective. However, the selection of the technical, operational and management security controls offered by the NIST model - and how they are implemented - does not always fit the nature and the environment where the ground system operates in even though there is no apparent impact on mission success. The authors observed that unfit controls, that is, controls that are not necessarily applicable or sufficiently effective in protecting the mission systems, are often selected to facilitate compliance with security requirements and organizational expectations even if the selected controls offer minimum or non-existent protection. This paper identifies some of the standard security controls that can in fact protect the ground system, and which of them offer little or no benefit at all. It offers multiple scenarios from real security audits in which the controls are not effective without, of course, disclosing any sensitive information about the missions assessed. In addition to selection and implementation of controls, the paper also discusses potential impact of recent legislation such as the Federal Information Security Modernization Act (FISMA) of 2014 - aimed at the enterprise - on the ground system, and offers other recommendations to Information System Owners (ISOs).

Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Spain and Grupo de Imaxe Molecular, IDIS, Santiago de Compostela 15706 (Spain); Pino, Francisco [Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Spain and Servei de Física Médica i Protecció Radiológica, Institut Catalá d' Oncologia, Barcelona 08036 (Spain); Silva-Rodríguez, Jesús [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Santiago de Compostela 15706 (Spain); Pavía, Javier [Servei de Medicina Nuclear, Hospital Clínic, Barcelona (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ros, Doménec [Unitat de Biofísica, Facultat de Medicina, Casanova 143 (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ruibal, Álvaro [Servicio Medicina Nuclear, CHUS (Spain); Grupo de Imaxe Molecular, Facultade de Medicina (USC), IDIS, Santiago de Compostela 15706 (Spain); Fundación Tejerina, Madrid (Spain); and others

2014-03-15

Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

International Nuclear Information System (INIS)

Aguiar, Pablo; Pino, Francisco; Silva-Rodríguez, Jesús; Pavía, Javier; Ros, Doménec; Ruibal, Álvaro

2014-01-01

Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

Evaluation of the performance of a metrohm titrator titrando-836 in potentiometric analysis of uranium for safeguards purposes

International Nuclear Information System (INIS)

Cristiano, Barbara Fernandes; Silva, Jose Wanderley S. da; Barros, Pedro Dionisio de; Araujo, Radier Mario S. de

2009-01-01

To achieve the requirements of the Brazilian State System of Accounting for and Control of Nuclear Materials - SSAC the Safeguards Laboratory of Brazilian Nuclear Energy Commission, LASAL, has been applying the 'Davies and Gray/NBL' method for Potentiometric determination of total uranium concentration in several forms of nuclear materials since 1984. To improve the accuracy and the repeatability the method uses as titrant, standard reference potassium dichromate NIST SRM 136e and the results are also corrected for bias with NBL CRM 112A uranium metal assay standard. This work describes the assays performed for validation of a Metrohm 836 potentiometric titrator acquired by LASAL in order to improve the analytical methodology of the laboratory. The titrator is attached to a Pt:Rh (90:10) as indicator electrode and a mercurous sulfate as the reference electrode. The evaluation of accuracy and repeatability were made by comparison, the results provided by the titrator with the certified value of standards and also by the participation in round robin program sponsored by New Brunswick Laboratory - NBL. The validation was done by a comparison of the performance between the Metrohm 836 and a Mettler - DL67 titrator which has currently been used by the laboratory. It included evaluation of the results of both equipment, the repeatability of the measurement, any systematic contributions and its uncertainties. (author)

Self-regulation method: psychological, physiological and clinical considerations. An overview.

Science.gov (United States)

Ikemi, A; Tomita, S; Kuroda, M; Hayashida, Y; Ikemi, Y

1986-01-01

Body-oriented therapies as relaxation training and certain forms of meditation are gaining popularity in the treatment and prevention of psychosomatic disorders. In this paper, a new method of self-control called self-regulation method (SRM), derived from autogenic training and Zen meditation, is presented. The technique of SRM is introduced. Secondly, physiological studies on SRM using skin temperature, galvanic skin response, and cortical evoked potentials are presented. Thirdly, the results of psychological tests conducted on SRM are presented. These psycho-physiological studies suggest that SRM may elicit a state of 'relaxed alertness'. Fourthly, clinical applications of SRM are discussed, and 3 cases are presented. Finally, SRM is discussed in relation to the psychology and physiology of 'relaxed alertness'.

Supplemental figure: Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at $\\mathbf{\\sqrt{{\\textit s}_{\\rm NN}}}$ = 2.76 TeV

CERN Document Server

2015-01-01

This note provides a supplemental figure for data on ``Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions $\\mathbf{\\sqrt{{\\textit s}_{\\rm NN}}}$ = 2.76~TeV" published in \\href{http://www.sciencedirect.com/science/article/pii/S037026931300004X}{Phys.\\ Lett.\\ B {\\bf 719}, 18 (2013)}, \\href{http://arxiv.org/abs/1205.5761}{arXiv:1205.5761}. The figure~(\\ref{fig:v2_pid}) presents the $v_2$ of charged pions and protons (particles and anti-particles are not distinguished in this analysis) from the event plane method as a function of transverse momentum for different centrality classes as reported in Fig. 5 of the \\href{http://www.sciencedirect.com/science/article/pii/S037026931300004X}{publication}. The proton $v_2$ is higher than that of pions out to $\\pt=8$~GeV/$c$ where the uncertainties become large.

Investigation of matrix effects in 193 nm laser ablation-inductively coupled plasma-mass spectrometry analysis using reference glasses of different transparencies

International Nuclear Information System (INIS)

Czas, J.; Jochum, K.P.; Stoll, B.; Weis, U.; Yang, Q.-C.; Jacob, D.E.; Andreae, M.O.

2012-01-01

The degree of transparency of glasses, which depends on the Fe content, may influence the ablation behavior during laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis. To test possible matrix effects when using a 193 nm Nd:YAG laser, we have analyzed transparent and opaque NIST, BAM and USGS reference glasses. These reference materials are ideal for such investigations, because they are well characterized, most elements are homogeneously distributed at the micrometer scale, and their Fe content varies over a very large range, from 16 to 130,000 μg g −1 . Our measurements show that the fractionation factors of refractory and volatile lithophile elements, such as Sr, Ba, and Rb, are 1.00 ± 0.03 and independent of the degree of transparency. However, for volatile chalcophile/siderophile elements (e.g., Zn and Pb) the fractionation factors vary significantly between 0.7 and 1, depending on the spot sizes and the transparency of the material. Mass-load-induced matrix effects may also influence the accuracy of LA-ICP-MS analysis. They are less than 2% for the lithophile and up to 10% for volatile chalcophile/siderophile elements when the mass load varies by a factor 2.4. Relative sensitivity factors used for calibration of lithophile elements agree within uncertainty limits for transparent and opaque glasses when using a 193 nm laser. Even for volatile/chalcophile elements they differ only by 5–10%. The reliability of the LA-ICP-MS analyses is demonstrated by presenting concentration data of 27 trace elements in the NIST, BAM and USGS reference glasses using NIST SRM 612 for calibration, where highly accurate reference values are available. For trace element concentrations in the range between 1 and 500 μg g −1 , the reproducibility and the uncertainties at the 95% confidence level of the measurements vary between 1–4%, and 7–10%, respectively. - Highlights: ► Matrix effects are low for lithophile elements using a 193 nm laser

A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Tuzen, Mustafa [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr; Citak, Demirhan [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Ferreira, Hadla S.; Korn, Maria G.A. [Universidade Federal da Bahia, Instituto de Quimica, 40170-290 Salvador (Brazil); Bezerra, Marcos A. [Universidade Estadual do Sudoeste da Bahia, 45200-190 Jequie (Brazil)

2009-03-15

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L{sup -1} nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 {mu}g L{sup -1}, respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 {mu}g L{sup -1}. The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.

A study of trace elements in some medicinal plants

International Nuclear Information System (INIS)

Islam, A.; Biswas, S.K.; Akhter, S.

1995-05-01

Twenty one medicinal plants (herbal) have been investigated for major, minor and trace elements using the proton induced X-ray emission (PIXE) method. The samples were collected from the local market in Dhaka city and they were analysed by the thick-target external beam technique of the PIXE method. The samples were exposed to the proton beam as 1-mm thick pellet 0 f 7 mm dia. and irradiated with 2.0 MeV proton having 10 nA beam intensity. for 10-20 μC irradiation, the concentration of 15 elements,K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Zr and Pb were measured by comparison with calibration factors obtained from a curve constructed on the basis of the NBS orchard leaf standard (SRM-1571) irradiated under identical experimental condition. The concentration of K and Ca observed in the samples were in the range of 0.34-5.96% and .11-3.98% respectively. For Mn, Fe, Cu, Zn, Cr, As and Pb the concentration ranges were 4.1-1100, 60-7600, 1.1-276, 7-164, 1.2-48, 1.1-31, and 3.1-128 mg/kg respectively. Ti, Br, Rb, Sr and Zr were also determined with variable accuracy. The validity of the procedure was established by analysing a NIST standard (tomato leaf). The results obtained were in good agreement with the certified values. 17 refs.,3 tables, 3 figs

PHYSICS AND SAFETY ANALYSIS FOR THE NIST RESEARCH REACTOR

International Nuclear Information System (INIS)

CHENG, L.; HANSON, A.; DIAMOND, D.; XU, J.; CAREW, J.; RORER, D.

2004-01-01

Detailed reactor physics and safety analyses have been performed for the 20 MW D 2 O moderated research reactor (NBSR) at the National Institute of Standards and Technology (NIST). The analyses provide an update to the Final Safety Analysis Report (FSAR) and employ state-of-the-art calculational methods. Three-dimensional Monte Carlo neutron and photon transport calculations were performed with the MCNP code to determine the safety parameters for the NBSR. The core depletion and determination of the fuel compositions were performed with MONTEBURNS. MCNP calculations were performed to determine the beginning, middle, and end-of-cycle power distributions, moderator temperature coefficient, and shim safety arm, beam tube and void reactivity worths. The calculational model included a plate-by-plate description of each fuel assembly, axial mid-plane water gap, beam tubes and the tubular geometry of the shim safety arms. The time-dependent analysis of the primary loop was determined with a RELAP5 transient analysis model that includes the pump, heat exchanger, fuel element geometry, and flow channels for both the six inner and twenty-four outer fuel elements. The statistical analysis used to assure protection from critical heat flux (CHF) was performed using a Monte Carlo simulation of the uncertainties contributing to the CHF calculation. The power distributions used to determine the local fuel conditions and margin to CHF were determined with MCNP. Evaluations were performed for the following accidents: (1) the control rod withdrawal startup accident, (2) the maximum reactivity insertion accident, (3) loss-of-flow resulting from loss of electrical power, (4) loss-of-flow resulting from a primary pump seizure, (5) loss-of-flow resulting from inadvertent throttling of a flow control valve, (6) loss-of-flow resulting from failure of both shutdown cooling pumps and (7) misloading of a fuel element. In both the startup and maximum reactivity insertion accidents, the core

A novel fiber-packed column for on-line preconcentration and speciation analysis of chromium in drinking water with flame atomic absorption spectrometry.

Science.gov (United States)

Monasterio, Romina P; Altamirano, Jorgelina C; Martínez, Luis D; Wuilloud, Rodolfo G

2009-02-15

A novel on-line preconcentration and determination system based on a fiber-packed column was developed for speciation analysis of Cr in drinking water samples prior to its determination by flame atomic absorption spectrometry (FAAS). All variables involved in the development of the preconcentration method including, pH, eluent type, sample and eluent flow rates, interfering effects, etc., were studied in order to achieve the best analytical performance. A preconcentration factor of 32 was obtained for Cr(VI) and Cr(III). The levels of Cr(III) species were calculated by difference of total Cr and Cr(VI) levels. Total Cr was determined after oxidation of Cr(III) to Cr(VI) with hydrogen peroxide. The calibration graph was linear with a correlation coefficient of 0.999 at levels near the detection limit and up to at least 50 microg L(-1). The relative standard deviation (R.S.D.) was 4.3% (C=5 microg L(-1) Cr(VI), n=10, sample volume=25 mL). The limit of detection (LOD) for both Cr(III) and Cr(VI) species was 0.3 microg L(-1). Verification of the accuracy was carried out by the analysis of a standard reference material (NIST SRM 1643e "Trace elements in natural water"). The method was successfully applied to the determination of Cr(III) and Cr(VI) species in drinking water samples.

Manajemen Risiko Keamanan Informasi Menggunakan Framework NIST SP 800-30 Revisi 1 (Studi Kasus: STMIK Sumedang

Directory of Open Access Journals (Sweden)

Fathoni Mahardika

2017-07-01

Full Text Available STMIK Sumedang merupakan institusi yang sudah terbiasa menggunakan perangkat teknologi, dimana pengawasannya dilakukan oleh suatu divisi tersendiri yaitu bagian UPT LPSI. Namun terdapat permasalahan dalam penggunaan TI yang ada saat ini antara lain : (1 Masih sering terjadinya insiden keamanan informasi yang menyebabkan terganggunya proses bisnis perusahaan, (2 Belum adanya pengawasan dan perencanaan yang tepat dalam pengelolaan keamanan informasi di STMIK Sumedang.Manajemen resiko adalah metode untuk penilaian dan mitigasi resiko terhadap aspek kebutuhan keamanan informasi yang memuat 3 unsur penting yaitu : Confidentiality (kerahasiaan, Integrity (integritas, dan Availability (ketersediaan. Manajemen resiko keamanan informasi yang digunakan mengacu pada NIST SP 800-30 Revisi 1. Standar ini digunakan sebagai acuan dalam melakukan manajemen resiko keamanan informasi, untuk mengantisipasi risiko agar kerugian tidak terjadi terhadap organisasi. Sehingga resiko dapat dikelola ke level yang dapat diterima organisasi. Diharapkan akan mengurangi dampak insiden sistem dan teknologi informasi di institusi perguruan tinggi, melindungi proses bisnis organisasi yang penting dari ancaman keamanan, meminimalisir risiko kerugian serta menghindari kegagalan serius terhadap informasi yang ada di STMIK Sumedang. Setelah dilakukan manajemen risiko maka diperlukan control keamanan sebagai dasar acuan bahwa risiko dilakukan mitigasi, diterima/ditransfer oleh pihak manajemen. Kontrol keamanan dikembangkan dari ISO 27002. Untuk mengetahui sejauh mana keamanan informasi organisasi maka dilakukan maturity keamanan informasi organisasi menggunakan control yang dikembangkan dari ISO 27002. Dari hasil maturity ini menjadi dasar dibuatnya rekomendasi standar kebijakan keamanan informasi di STMIK Sumedang.

Students' Motivation to Learn in Middle School--A Self-Regulated Learning Approach

Science.gov (United States)

Paulino, Paula; Sá, Isabel; Lopes da Silva, Adelina

2016-01-01

Introduction: The self-regulation of motivation (SRM) is conceptualized as a meta-motivational process that guides students' efforts and persistence when performing tasks. This process regulates students' behavior through strategies that are influenced by motivational beliefs. SRM allows students to motivate themselves and guides their behavior.…

Method of reactor fueling

International Nuclear Information System (INIS)

Saito, Toshiro.

1983-01-01

Purpose: To decrease the cost and shorten the working time by saving fueling neutron detectors and their components. Method: Incore drive tubes for the neutron source range monitor (SRM) and intermediate range monitor (IRM) are disposed respectively within in a reactor core and a SRM detector assembly is inserted to the IRM incore drive tube which is most nearest to the neutron source upon reactor fueling. The reactor core reactivity is monitored by the SRM detector assembly. The SRM detector asesembly inserted into the IRM drive tube is extracted at the time of charging fuels up to the frame connecting the SRM and, thereafter, IRM detection assembly is inserted into the IRM drive tube and the SRM detector assembly is inserted into the SRM drive tube respectively for monitoring the reactor core. (Sekiya, K.)

A new two-phase homopolar switched reluctance motor for electric vehicle applications

Science.gov (United States)

Tsai, Mi-Ching; Huang, Chien-Chin; Huang, Zheng-Yi

2003-12-01

This paper presents a novel 2-phase homopolar switched reluctance motor (SRM), whose design successfully avoids dead-zone problems that afflict low cost 1- and/or 2-phase SRMs. Unlike conventional radial-winding-radial-gap motors, the proposed SRM has an interior stator that is of the pancake type with axial winding. Such a design allows for a high slot-fill factor and is suitable for implementation as a flat pancake-shaped stator. An efficient, compact prototype was produced with TMS320F240 DSP driving control unit. Experimental results indicate that the present SRM design has the potential to be used for electric bicycles and scooters.

Is there room for geoengineering in the optimal climate policy mix?

International Nuclear Information System (INIS)

Bahn, Olivier; Chesney, Marc; Gheyssens, Jonathan; Knutti, Reto; Pana, Anca Claudia

2015-01-01

Highlights: • We investigate the optimal policy mix for dealing with climate change. • We consider jointly mitigation, adaptation, and solar radiation management (SRM). • SRM can control temperature, but brings environmental side-effects. • SRM is not robust due to uncertainty in magnitude and persistency of side-effects. • Implementing SRM with wrong assumptions about side-effects largely decreases welfare. - Abstract: We investigate geoengineering as a possible substitute for mitigation and adaptation measures to address climate change. Relying on an integrated assessment model, we distinguish between the effects of solar radiation management (SRM) on atmospheric temperature levels and its side-effects on the environment. The optimal climate portfolio is a mix of mitigation, adaptation, and SRM. When accounting for uncertainty in the magnitude of SRM side-effects and their persistency over time, we show that the SRM option lacks robustness. We then analyse the welfare consequences of basing the SRM decision on wrong assumptions about its side-effects, and show that total output losses are considerable and increase with the error horizon. This reinforces the need to balance the policy portfolio in favour of mitigation

Modeling of a Switched Reluctance Motor under Stator Winding Fault Condition

DEFF Research Database (Denmark)

Chen, Hao; Han, G.; Yan, Wei

2016-01-01

A new method for modeling stator winding fault with one shorted coil in a switched reluctance motor (SRM) is presented in this paper. The method is based on artificial neural network (ANN), incorporated with a simple analytical model in electromagnetic analysis to estimate the flux-linkage charac......A new method for modeling stator winding fault with one shorted coil in a switched reluctance motor (SRM) is presented in this paper. The method is based on artificial neural network (ANN), incorporated with a simple analytical model in electromagnetic analysis to estimate the flux......-linkage characteristics of SRM under the stator winding fault. The magnetic equivalent circuit method with ANN is applied to calculate the nonlinear flux-linkage characteristics under stator winding fault condition. A stator winding fault 12/8 SRM prototype system is developed to verify the effectiveness of the proposed...... method. The results for a stator winding fault with one shorted coil are obtained from the proposed method and from the experimental work on a developed prototype. It is shown that the simulation results are close to the test results....

Human Response to Potential Robust Climate Change around 5500 cal BP in the Territory of Bohemia (the Czech Republic)

Czech Academy of Sciences Publication Activity Database

Dreslerová, Dagmar

2012-01-01

Roč. 3, č. 1 (2012), s. 43-55 ISSN 1804-848X Institutional support: RVO:67985912 Keywords : Holocene * Neolithic * environment * climate Subject RIV: AC - Archeology, Anthropology, Ethnology http://www.iansa.eu/papers/IANSA-2012-01-dreslerova.pdf

Reference measurement procedure for the determination of electrolytes in human blood via ICP-OES measurement

Science.gov (United States)

Grote-Koska, D.; Klauke, R.; Brand, K.; Schumann, G.

2018-04-01

The determination of electrolytes in human body fluids is one of the most frequently performed analyses in clinical routine laboratories. Metrological traceability of measurement results in patient samples is essential and requires the involvement of higher order reference measurement procedures wherever available. Here, the authors present the evaluation of a higher order reference system for the simultaneous determination of K+, Li+, Na+, Ca2+ and Mg2+ in blood serum and plasma. In the same order, the determined measurement performances were as follows: measurement ranges: 0.75 mmol l-1-75.0 mmol l-1, 0.05 mmol l-1-5.00 mmol l-1, 5 mmol l-1-200 mmol l-1, 0.4 mmol l-1-8.0 mmol l-1 and 0.1 mmol l-1-4.0 mmol l-1. Measurement imprecision: CVs were  ⩽1.1% for intra assay investigations and  ⩽1.8% for long term inter assay investigations for all measurands. Excellent accuracy was found testing certified Standard Reference Materials from NIST: SRM 909 (deviations from 0.0% to 1.1%) and SRM 956 (deviations from 0.0% to 1.5%). Intercomparisons with the German Metrology Institute (PTB) revealed differences from 0.1% to 0.8%. Matrix influences and carry over were not detectable. The expanded combined measurement uncertainties for the determination of the reference method values were estimated as  ⩾1.5% (k  =  2) for each measurand. The reference measurement procedure is accredited by the German accreditation body (DAkkS) in association with the German calibration service (DKD) according to ISO 17025 and ISO 15195. Services comprise the certification of calibrators, control materials and samples used in proficiency testing schemes.

DNA damage and cytotoxicity in type II lung epithelial (A549) cell cultures after exposure to diesel exhaust and urban street particles

DEFF Research Database (Denmark)

Danielsen, Pernille Høgh; Loft, Steffen; Møller, Peter

2008-01-01

ABSTRACT: BACKGROUND: Exposure to air pollution particles has been acknowledged to be associated with excess generation of oxidative damage to DNA in experimental model systems and humans. The use of standard reference material (SRM), such as SRM1650 and SRM2975, is advantageous because experiments...... collected at a traffic intensive road in Copenhagen, Denmark. RESULTS: All of the particles generated strand breaks and oxidized purines in A549 lung epithelial cells in a dose-dependent manner and there were no overt differences in their potency. The exposures also yielded dose-dependent increase...... of cytotoxicity (as lactate dehydrogenase release) and reduced colony forming ability with slightly stronger cytotoxicity of SRM1650 than of the other particles. In contrast, only the authentic street particles were able to generate 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in calf thymus DNA, which might...

Determination of inorganic beryllium species in the particulate matter of emissions and working areas

Energy Technology Data Exchange (ETDEWEB)

Profumo, A.; Spini, G.; Cucca, L.; Pesavento, M. [Dipartimento di Chimica Gen., Pavia (Italy)

2002-07-01

A sequential extraction procedure for separating and determining Be(0), soluble Be(II) inorganic compounds, BeO and beryllium silicates in samples, such as particulate matter of emissions and working areas, has been developed. The proposed procedure has been tested on synthetic samples prepared with the inorganic beryllium compounds, in the presence of atmospherical particulate matter sampled in a laboratory, previously checked for the absence of beryllium. The speciation was then repeated on a sample of fly ash deriving from a solid waste incinerator and on a reference material (Coal Fly ash SRM 1633a, by NIST), followed by an evaluation of matrix spiking and recovery analyses. Performing multiple analyses of the spiked samples assessed the repeatability of the procedure. Quantitative determinations have been made by inductively coupled plasma optical emission spectrometry (ICP-OES) and electrothermal atomic absorption spectrometry (ETAAS). The possible interferences of the most common ions have been investigated. The selective sequential extractions allow one to separate and to determine different inorganic beryllium species, to which a different toxicity and therefore, a different risk are related: it is the case for example of metallic beryllium and beryllium oxide.

Elemental analysis of essential and toxic content in tea and its infusion used by neutron activation

International Nuclear Information System (INIS)

Th-Rina Mulyaningsih

2011-01-01

Concentration of metal elements K, Ca, Mn, Mg, Fe, Na, Zn, Rb, Br, Cr, Cs, La,Sc and Co from 14 samples of green and black tea with aroma of jasmine, vanilla, roselle flower and tea infusion have been determined by means of neutron activation analysis. The Samples were chosen from the domestic product and were collected from Supermarket in Serpong region. Neutron irradiation of the samples was carried out in the Irradiation Facility of the RSG-GAS reactor at thermal neutron flux in the order of 1,013ncm -2 s -1 .The working procedures follow the Standard Operating Procedures of FNCA. As of the quality control the reference material of SRM-NIST 1573a Tomato leaves and NIST 1,547 Peach leaves have been applied. The analysis results show that concentration of the elements variate depending on the sort of tea.Concentration of Ca, K, Mg dan Mn have a rather high value namely >100 mg/kg. Concentration of Ca and K have values in a range of 1,135.36 - 9,123.21 and 1,064.41-2,473.12 mg/kg as well as Mg of 2,725.6 - 5,528.5; and Mn of 95.38 - 815.48 mg/kg.Concentration of Na, Fe, Co, La, Cr, Br, Sc, Cs, Rb and Zn <100 mg/kg. Most elements in these tea were released into the infusions at different percentages in a range of 27.89 - 68.94% depending on the sort of the tea. There were not detected toxic elements Hg, Cd and As except Cr with low concentration. Therefore tea drinks are adequately good enough as essential elements source and content no toxic elements. (author)

Field experiments on solar geoengineering: report of a workshop exploring a representative research portfolio.

Science.gov (United States)

Keith, David W; Duren, Riley; MacMartin, Douglas G

2014-12-28

We summarize a portfolio of possible field experiments on solar radiation management (SRM) and related technologies. The portfolio is intended to support analysis of potential field research related to SRM including discussions about the overall merit and risk of such research as well as mechanisms for governing such research and assessments of observational needs. The proposals were generated with contributions from leading researchers at a workshop held in March 2014 at which the proposals were critically reviewed. The proposed research dealt with three major classes of SRM proposals: marine cloud brightening, stratospheric aerosols and cirrus cloud manipulation. The proposals are summarized here along with an analysis exploring variables such as space and time scale, risk and radiative forcing. Possible gaps, biases and cross-cutting considerations are discussed. Finally, suggestions for plausible next steps in the development of a systematic research programme are presented.

Solid-phase extraction and separation procedure for trace aluminum in water samples and its determination by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS).

Science.gov (United States)

Ciftci, Harun; Er, Cigdem

2013-03-01

In the present study, a separation/preconcentration procedure for determination of aluminum in water samples has been developed by using a new atomic absorption spectrometer concept with a high-intensity xenon short-arc lamp as continuum radiation source, a high-resolution double-echelle monochromator, and a charge-coupled device array detector. Sample solution pH, sample volume, flow rate of sample solution, volume, and concentration of eluent for solid-phase extraction of Al chelates with 4-[(dicyanomethyl)diazenyl] benzoic acid on polymeric resin (Duolite XAD-761) have been investigated. The adsorbed aluminum on resin was eluted with 5 mL of 2 mol L(-1) HNO(3) and its concentration was determined by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Under the optimal conditions, limit of detection obtained with HR-CS FAAS and Line Source FAAS (LS-FAAS) were 0.49 μg L(-1) and 3.91 μg L(-1), respectively. The accuracy of the procedure was confirmed by analyzing certified materials (NIST SRM 1643e, Trace elements in water) and spiked real samples. The developed procedure was successfully applied to water samples.

Application of inductively coupled plasma mass spectrometry for multielement analysis in small sample amounts of thyroid tissue from Chernobyl area

International Nuclear Information System (INIS)

Becker, J.S.; Dietze, H.J.; Boulyga, S.F.; Bazhanova, N.N.; Kanash, N.V.; Malenchenko, A.F.

2000-01-01

As a result of the Chernobyl nuclear power plant accident in 1986, thyroid pathologies occurred among children in some regions of belarus. Besides the irradiation of children's thyroids by radioactive iodine and caesium nuclides, toxic elements from fallout are a direct risk to health. Inductively coupled plasma quadrupole-based mass spectrometry (Icp-Ms) and instrumental neutron activation analysis (IAA) were used for multielement determination in small amounts (I-10 mg) of human thyroid tissue samples. The accuracy of the applied analytical technique for small biological sample amounts was checked using NIST standard reference material oyster tissue (SRM 1566 b). Almost all essential elements as well as a number of toxic elements such as Cd, Pb, Hg, U etc. Were determined in a multitude of human thyroid tissues by quadrupole-based Icp-Ms using micro nebulization. In general, the thyroid tissue affected by pathology is characterized by higher calcium content. Some other elements, among them Sr, Zn, Fe, Mn, V, As, Cr, Ni, Pb, U, Ba, Sb, were also Accumulated in such tissue. The results obtained will be used as initial material for further specific studies of the role of particular elements in thyroid pathology development

Tracing lead pollution sources in abandoned mine areas using stable Pb isotope ratios.

Science.gov (United States)

Yoo, Eun-Jin; Lee, Jung-A; Park, Jae-Seon; Lee, Khanghyun; Lee, Won-Seok; Han, Jin-Seok; Choi, Jong-Woo

2014-02-01

This study focused on Pb isotope ratios of sediments in areas around an abandoned mine to determine if the ratios can be used as a source tracer. For pretreatment, sediment samples were dissolved with mixed acids, and a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Nu plasma II) was used to investigate the Pb isotopic composition of the samples. The measured isotope ratios were then corrected for instrumental mass fractionation by measuring the (203)Tl/(205)Tl ratio. Repeated measurements with the NIST SRM 981 reference material showed that the precision of all ratios was below 104 ppm (±2σ) for 50 ng/g. The isotope ratios ((207)Pb/(206)Pb) found were 0.85073 ± 0.0004~0.85373 ± 0.0003 for the main stream, while they were 0.83736 ± 0.0010 for the tributary and 0.84393 ± 0.0002 for the confluence. A binary mixing equation for isotope ratios showed that the contributions of mine lead to neighboring areas were up to 60%. Therefore, Pb isotope ratios can be a good source tracer for areas around abandoned mines.

SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

Energy Technology Data Exchange (ETDEWEB)

Zhao, F [Duke University Medical Center, Durham, NC (United States); Shandong Cancer Hospital and Insititute, Jinan, Shandong (China); Bowsher, J; Palta, M; Czito, B; Willett, C; Yin, F [Duke University Medical Center, Durham, NC (United States)

2014-06-01

Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purpose of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered.

SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

International Nuclear Information System (INIS)

Zhao, F; Bowsher, J; Palta, M; Czito, B; Willett, C; Yin, F

2014-01-01

Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purpose of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered

The effect of uncertainty of reactor parameters obtained using k0-NAA on result of analysis

International Nuclear Information System (INIS)

Sasajima, Fumio

2006-01-01

Neutron Activation Analysis using the k 0 method is a useful method allowing convenient and accurate simultaneous analysis of plural elements, eliminating the need for the use of comparative reference samples. As already well known, it is essential for the correct result of an analysis to obtain the α-factor and f-factor for a neutron spectrum in an irradiation field accurately when an attempt is made to use the k 0 method. For this reason, based on data obtained from the experiment conducted in the JRR-3 PN-3 system, how uncertainty of the measured values for α-factor and f-factor affects the result of an analysis was evaluated. The process of evaluation involved intentionally varying the values for reactor parameters followed by making an analysis of environmental reference samples (NIST SRM-1632c) using the k 0 method to examine the effect of these factors on the concentrations of 19 elements. The result of the evaluation revealed that the degree of the effect of uncertainty on the concentrations of 19 elements was at best approx. 1% under the condition of this experiment assuming that the factor α, a reactor parameter, had uncertainty of approx. 200%. (author)

Biolistic transmission of potato spindle tuber viroid (PSTVd) populations to weeds frequently grown on potato fields and PSTVd pathogenesis on cultured Chamomilla recutita

Czech Academy of Sciences Publication Activity Database

Matoušek, Jaroslav; Orctová, Lidmila; Ptáček, J.; Dědič, P.

2009-01-01

Roč. 16, č. 1 (2009), s. 43-55 ISSN 1802-940X Institutional research plan: CEZ:AV0Z50510513 Keywords : potato fields * weed plants * potato spindle tuber viroid (PSTVd) Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

Public understanding of solar radiation management

International Nuclear Information System (INIS)

Mercer, A M; Keith, D W; Sharp, J D

2011-01-01

We report the results of the first large-scale international survey of public perception of geoengineering and solar radiation management (SRM). Our sample of 3105 individuals in the United States, Canada and the United Kingdom was recruited by survey firms that administer internet surveys to nationally representative population samples. Measured familiarity was higher than expected, with 8% and 45% of the population correctly defining the terms geoengineering and climate engineering respectively. There was strong support for allowing the study of SRM. Support decreased and uncertainty rose as subjects were asked about their support for using SRM immediately, or to stop a climate emergency. Support for SRM is associated with optimism about scientific research, a valuing of SRM's benefits and a stronger belief that SRM is natural, while opposition is associated with an attitude that nature should not be manipulated in this way. The potential risks of SRM are important drivers of public perception with the most salient being damage to the ozone layer and unknown risks. SRM is a new technology and public opinions are just forming; thus all reported results are sensitive to changes in framing, future information on risks and benefits, and changes to context.

Studies of zinc(II in pharmaceutical and biological samples by extractive spectrophotometry: using pyridoxal-4-phenyl-3-thiosemicarbazone as chelating reagent

Directory of Open Access Journals (Sweden)

Sarma L. Subramanyam

2006-01-01

Full Text Available Pyridoxal-4-phenyl-3-thiosemicarbazone (PPT is proposed as a new sensitive reagent for the sensitive extractive spectrophotometric determination of zinc(II. PPT reacts with zinc(II in the pH range 5.0-6.0 to form a yellow colored complex, which was well extracted into n-butanol. The absorbance value of Zn(II-PPT complex was measured at different intervals of time at 430 nm, to ascertain the stability of the complex. It was observed that the color development was instantaneous and stable for more than 48 h. The system obeyed Beer's law up to 6.0 µg mL-1 of zinc(II, with an excellent linearity in terms of correlation coefficient value of 0.999. The molar absorptivity and Sandell's sensitivity of the extracted species is 1.6 X 10(4 L mol-1 cm-1 and 4.085 X 10-3 µg cm-2 at 430 nm. The detection limit of the method is 0.04 µg mL-1. To assess precision of the method, determinations were carried out at different concentrations; the relative standard deviation does not exceed 3.1%. The composition of the zinc(II complex with PPT was studied by the method of Job's continuous variation, molar ratio method, Asmus' method and slope ratio method. It has been satisfactorily applied for the determination of zinc(II, when present alone or in presence of diverse ions, which are usually associated with zinc(II in pharmaceutical and biological samples. Various certified reference materials (NIST 1573, NBS 1572 and NIST SRM 8435 have been tested for the determination of zinc for evaluating the accuracy of the developed method. The results of the proposed method are in agreement with flame atomic absorption spectometry.

Drawing up of a procedure for vanadium determination in mussels using the neutron activation analysis method

International Nuclear Information System (INIS)

Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiko; Catharino, Marilia G.M.; Moreira, Edson G.; Sousa, Eduinetty C.P.M. de; Pereira, Camilo D.S.

2009-01-01

This work establishes an adequate procedure for obtaining reliable results for determination of vanadium in mussels, leg by leg by the neutron activation analysis (NAA), viewing the posterior application on the bio monitoring the coastal pollution, particularly near the petroleum terminals.For the evaluation of result quality concerning to the quality of those results, the work analysed the reference material certification NIST SRM 1566b Oyster Tissue. The precision of the results were also analysed using repetitions of mussel samples collected at the coastal of northern Sao Paulo state, Brazil. The NAA procedure consisted of 200 mg of sample and a synthetic standard of vanadium during a period of 8 s and under a thermal neutron flux of 6.6 x 10 12 n cm -2 s -1 at the pneumatic station 4 of the IEA-R1 nuclear reactor of IPEN-CNEN/SP. After a 3 min decay, the measurements of the gamma activities of the sample and the standard were done using a Ge hyper pure semi-conductor detector, connected to gamma ray multichannel analyser. The vanadium were determined by the measurement of the gamma activity of the 52 V through the 1434.08 keV peak, and half-life time of 3.75 min. The concentration of V were calculated by the comparative method. The obtained results indicated the viability of the NAA procedure established for the determination of vanadium in mussels

Determination of essential elements in commercial baby foods by INAA (Instrumental Neutron Activation Analysis)

International Nuclear Information System (INIS)

Vallinoto, Priscila; Maihara, Vera A.

2011-01-01

The World Health Organization recommends that infants be breast feed exclusively at least six months after birth. After this period, it is recommended to introduce complementary foods, in order to meet nutritional amounts, minerals and energy needs of children. Commercial food products intended for infants form an important part of the diet for many babies, so it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of malnutrition in developing countries. In this study, essential elements: Ca, Co, Cr, Cs, Fe, K, Na and Zn levels were determined in seven different commercial food products samples by Instrumental Neutron Activation Analysis. The seven baby food samples were acquired in the markets of Sao Paulo city. After 8-hour irradiations in the IEA-R1 nuclear research reactor under a thermal neutron flux of 10 12 n cm -2 s -1 , the essential elements were determined and the concentrations obtained were lower than the WHO requirements. For validation of the methodology, INCT MPH-2 Mixed Polish Herbs and NIST SRM 1577 b Bovine Liver were analysed. (author)

Measurement of polybrominated diphenyl ethers in environmental matrix standard reference materials

Energy Technology Data Exchange (ETDEWEB)

Stapleton, H.; Schantz, M.; Wise, S. (National Institute of Standards and Technology)

2004-09-15

Polybrominated diphenyl ethers (PBDEs) are a class of emerging contaminants of concern as many studies have now demonstrated that these compounds are bioaccumulative, persistent and increasing in concentration in the environment. PBDEs are being detected in almost every environmental sample examined, and they have even been measured in samples collected in the Arctic, further demonstrating their persistence and potential for long range transport. More and more studies are continuing to examine the fate and transport of these flame retardant compounds in environmental samples and as such, reference materials are needed to provide quality control on these measurements. The National Institute of Standards and Technology (NIST) supports a national Standard Reference Material (SRM) program for measurement of organic contaminants such as PCBs, PAHs and chlorinated pesticides in environmental matrices. This current study was undertaken to provide reference measurements for PBDEs in selected SRMs that are currently used by various laboratories throughout the United States. These SRMs include matrices such as marine mammal blubber, lake trout tissue, mussel tissue, sediment, house dust and human serum. We report here reference values for 22 PBDE congeners that have been quantified in these seven types of SRMs.

Determination of essential elements in commercial baby foods by INAA (Instrumental Neutron Activation Analysis)

Energy Technology Data Exchange (ETDEWEB)

Vallinoto, Priscila; Maihara, Vera A., E-mail: pvallinoto@ipen.br, E-mail: vmaihara@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The World Health Organization recommends that infants be breast feed exclusively at least six months after birth. After this period, it is recommended to introduce complementary foods, in order to meet nutritional amounts, minerals and energy needs of children. Commercial food products intended for infants form an important part of the diet for many babies, so it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of malnutrition in developing countries. In this study, essential elements: Ca, Co, Cr, Cs, Fe, K, Na and Zn levels were determined in seven different commercial food products samples by Instrumental Neutron Activation Analysis. The seven baby food samples were acquired in the markets of Sao Paulo city. After 8-hour irradiations in the IEA-R1 nuclear research reactor under a thermal neutron flux of 10{sup 12} n cm{sup -2} s{sup -1}, the essential elements were determined and the concentrations obtained were lower than the WHO requirements. For validation of the methodology, INCT MPH-2 Mixed Polish Herbs and NIST SRM 1577{sup b} Bovine Liver were analysed. (author)

Preparation and certification of solutions of perdeuterated polycyclic aromatic compounds intended for use as surrogate internal standards

International Nuclear Information System (INIS)

Quilliam, M.A.; Hardstaff, W.R.; Anacleto, J.F.; LeBlanc, M.D.; Stergiopoulos, V.; Dick, K.L.; Bowser, M.T.; Curtis, J.M.; Embree, D.J.; Sim, P.G.; Boyd, R.K.

1994-01-01

Two standard solutions of deuterated polycyclic aromatic compounds (PACs) have been prepared for use as surrogate internal standards. Solution DPAC-1 contains 21 deuterated PACs, and is intended for use with mass spectrometric (MS) detection. Most of the difficulties in certifying concentrations in DPAC-1 arose from the fact that none of the individual compounds was 100% deuterated, so that effects of mass spectrometric fragmentation are convoluted with those of isotopic distributions. The best methods are discussed for using such internal standards so as to minimize these problems, together with those arising from kinetic isotope effects. Solution DPAC-2 contains 6 deuterated PACs, and is primarily intended for use with reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection (FLD, dural programmed wavelength mode), in which the signals for analyte and internal standard are separated chromatographically rather than via the detector. Full details of the preparation of these solutions are described. In addition, examples of their use in the analysis of a certified coal-tar extract (NIST SRM 1597) are described briefly. In one example a novel HPLC-MS technique was employed, and in the other the HPLC-FLD technique was used. (orig.)

Core Sulphate-Reducing Microorganisms in Metal-Removing Semi-Passive Biochemical Reactors and the Co-Occurrence of Methanogens

Directory of Open Access Journals (Sweden)

Maryam Rezadehbashi

2018-02-01

Full Text Available Biochemical reactors (BCRs based on the stimulation of sulphate-reducing microorganisms (SRM are emerging semi-passive remediation technologies for treatment of mine-influenced water. Their successful removal of metals and sulphate has been proven at the pilot-scale, but little is known about the types of SRM that grow in these systems and whether they are diverse or restricted to particular phylogenetic or taxonomic groups. A phylogenetic study of four established pilot-scale BCRs on three different mine sites compared the diversity of SRM growing in them. The mine sites were geographically distant from each other, nevertheless the BCRs selected for similar SRM types. Clostridia SRM related to Desulfosporosinus spp. known to be tolerant to high concentrations of copper were members of the core microbial community. Members of the SRM family Desulfobacteraceae were dominant, particularly those related to Desulfatirhabdium butyrativorans. Methanogens were dominant archaea and possibly were present at higher relative abundances than SRM in some BCRs. Both hydrogenotrophic and acetoclastic types were present. There were no strong negative or positive co-occurrence correlations of methanogen and SRM taxa. Knowing which SRM inhabit successfully operating BCRs allows practitioners to target these phylogenetic groups when selecting inoculum for future operations.

A randomised double-blind placebo-controlled pilot trial of a combined extract of sage, rosemary and melissa, traditional herbal medicines, on the enhancement of memory in normal healthy subjects, including influence of age.

Science.gov (United States)

Perry, N S L; Menzies, R; Hodgson, F; Wedgewood, P; Howes, M-J R; Brooker, H J; Wesnes, K A; Perry, E K

2018-01-15

To evaluate for the first time the effects of a combination of sage, rosemary and melissa (Salvia officinalis L., Rosmarinus officinalis L. and Melissa officinalis L.; SRM), traditional European medicines, on verbal recall in normal healthy subjects. To devise a suitable study design for assessing the clinical efficacy of traditional herbal medicines for memory and brain function. Forty-four normal healthy subjects (mean age 61 ± 9.26y SD; m/f 6/38) participated in this study. A double-blind, randomised, placebo-controlled pilot study was performed with subjects randomised into an active and placebo group. The study consisted of a single 2-week term ethanol extract of SRM that was chemically-characterised using high resolution LC-UV-MS/MS analysis. Immediate and delayed word recall were used to assess memory after taking SRM or placebo (ethanol extract of Myrrhis odorata (L.) Scop.). In addition analysis was performed with subjects divided into younger and older subgroups (≤ 62 years mean age n = 26: SRM n = 10, Placebo n = 16; ≥ 63 years n = 19: SRM n = 13, Placebo n = 6). Overall there were no significant differences between treatment and placebo change from baseline for immediate or delayed word recall. However subgroup analysis showed significant improvements to delayed word recall in the under 63 year age group (p memory in healthy subjects under 63 years of age. Short- and long- term supplementation with SRM extract merits more robust investigation as an adjunctive treatment for patients with Alzheimer's disease and in the general ageing population. The study design proved a simple cost effective trial protocol to test the efficacy of herbal medicines on verbal episodic memory, with future studies including broader cognitive assessment. Copyright © 2017 Elsevier GmbH. All rights reserved.

Determination of copper and mercury in phosphate fertilizers employing direct solid sampling analysis and high resolution continuum source graphite furnace atomic absorption spectrometry

Science.gov (United States)

de Oliveira Souza, Sidnei; François, Luciane Luiza; Borges, Aline Rocha; Vale, Maria Goreti Rodrigues; Araujo, Rennan Geovanny Oliveira

2015-12-01

The present study proposes the determination of copper and mercury in phosphate fertilizers by direct solid sampling analysis (SS) employing high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). For Cu determination, two analytical lines were used: 327.3960 nm and 249.2146 nm. Hg determination was carried out on the line 253.6521 nm and 100 μg KMnO4 was used as chemical modifier. The optimal pyrolysis temperature for Cu determination was 1300 °C. Atomization temperatures for Cu and Hg were 2400 and 1100 °C, respectively. External calibration with aqueous standard solutions was adopted for both elements. The limits of quantification (LoQs) and characteristic mass (m0) obtained for Cu determination were 0.4 μg g- 1 and 1.12 ng, respectively, on line 249.2146 nm, and 64 μg g- 1 and 25 pg on 327.3960 nm. For mercury, LoQ and m0 were 4.8 ng g- 1 and 39 pg, respectively. The accuracy of the proposed methods was confirmed by the analysis of standard reference material (SRM) of Trace Elements in Multi-Nutrient Fertilizer (SRM NIST 695). The precision expressed as relative standard deviation (RSD), was better than 8.2% for Hg and 7.7% for the Cu (n = 5), considered satisfactory for microanalysis in solid sample. Four fertilizer samples acquired in commercial establishments in the city of Salvador, Bahia, Brazil, were analyzed. The optimized analytical methods were simple, fast, accurate, precise and free of spectral interferences for the determination of Cu and Hg in phosphate fertilizer samples by SS-HR-CS GF AAS, avoiding the dissolution of the sample, the use of harmful reagents and the generation of residues.

Movement and spatial proximity patterns of rangeland-raised Raramuri Criollo cow-calf pairs

Science.gov (United States)

The objective of this study was to compare movement patterns of nursing vs. nonnursing mature cows and to characterize cow-calf proximity patterns in two herds of Raramuri Criollo cattle. Herds grazed rangeland pastures in southern New Mexico (4355 ha) and west-central Chihuahua, Mexico (633 ha)'' A...

Enhanced Control of Listeria monocytogenes by Enterococcus faecium KE82, a Multiple Enterocin-Producing Strain, in Different Milk Environments.

Science.gov (United States)

Vandera, Elpiniki; Lianou, Alexandra; Kakouri, Athanasia; Feng, Jinbo; Koukkou, Anna-Irini; Samelis, John

2017-01-01

Enterococcus faecium KE82, isolated from traditional Greek Graviera cheese, was identified in pure broth cultures in vitro as a multiple enterocin-producing bacterial strain possessing the structural entA, entB, and entP enterocin genes. E. faecium KE82 was further assessed for in situ antilisterial activity in raw milk (RM) and commercially thermized milk (TM; 63°C for 30 s) in the presence of the indigenous microbiota and in sterile raw milk (SRM; 121°C for 5 min) with or without the addition of two commercial starter culture (CSC) strains Streptococcus thermophilus and Lactococcus lactis . Growth of Listeria monocytogenes was completely inhibited in RM incubated at 37°C for 6 h, whereas the pathogen was significantly inactivated in RM+KE82 samples during further incubation at 18°C for 66 h. In contrast, L. monocytogenes levels increased by approximately 2 log CFU/ml in TM, but in TM+KE82 samples, pathogen growth was retarded during the first 6 h at 37°C followed by growth cessation and partial inactivation at 18°C. After 48 to 72 h, growth of L. monocytogenes in SRM+CSC samples decreased by 4 to 5 log CFU/ml compared with the SRM control, whereas additional 10-fold decreases in the pathogen were observed in SRM+CSC+KE82 samples. Reverse transcription PCR analysis of SRM+KE82 and SRM+CSC+KE82 samples confirmed that the entA and entB genes were transcribed, but entP gene transcription was not detected. All RM and SRM samples inoculated with E. faecium KE82 displayed strong in situ inhibitory activity against L. monocytogenes in well diffusion bioassays, whereas activity was weaker to undetectable in comparable or additional TM+KE82 samples; no milk sample without E. faecium KE82 had activity against L. monocytogenes . The findings of this study indicate that E. faecium KE82 is an antilisterial agent that could be used in traditional dairy foods because it concomitantly produces enterocins A and B in situ in milk.

Determination of essential elements in edible seaweed by neutron activation analysis

International Nuclear Information System (INIS)

Alves, Cassio Bessa Lima; Maihara, Vera Akiko

2013-01-01

Comestible marine algae are gaining wider global trade, not only because of the taste but also the nutritional quality they present. They are rich in protein, fiber, vitamins and are excellent sources of essential elements due to their ability to absorb substances storing them in their bodies. its chemical composition varies according to the species, habitat, maturity and environmental conditions which are submitted. The method of Neutron Activation Analysis was used to determine the essential elements Cl, K, Mg, Mn and Na present in marine algae from different countries, which are sold in the city of Sao Paulo. A total of 6 samples of marine algae were analyzed, 4 species of Nori (Porphyra umbilicates) from China, Korea, Japan and USA; 1 of Hijiki (Hijikia fusiforme) species from Japan; and 1 species of Kombu (Laminaria sp.) of South Korea. To validate the methodology used was the reference material NIST SRM 1577b Bovine Liver. The concentrations range from 5265-1175 μg/g to CL; from 14413-90261 μg/g to K; from 3007-7091 μg/g to Mg; from 2,3-33,8 μg/g to Mn and from 5161-24973 μg/g to Na

Determination of essential elements in edible seaweed by neutron activation analysis; Determinacao de elementos essenciais em algas marinhas comestiveis por analise por ativacao neutronica

Energy Technology Data Exchange (ETDEWEB)

Alves, Cassio Bessa Lima; Maihara, Vera Akiko, E-mail: cassio_man@hotmail.com, E-mail: vmaihara@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Comestible marine algae are gaining wider global trade, not only because of the taste but also the nutritional quality they present. They are rich in protein, fiber, vitamins and are excellent sources of essential elements due to their ability to absorb substances storing them in their bodies. its chemical composition varies according to the species, habitat, maturity and environmental conditions which are submitted. The method of Neutron Activation Analysis was used to determine the essential elements Cl, K, Mg, Mn and Na present in marine algae from different countries, which are sold in the city of Sao Paulo. A total of 6 samples of marine algae were analyzed, 4 species of Nori (Porphyra umbilicates) from China, Korea, Japan and USA; 1 of Hijiki (Hijikia fusiforme) species from Japan; and 1 species of Kombu (Laminaria sp.) of South Korea. To validate the methodology used was the reference material NIST SRM 1577b Bovine Liver. The concentrations range from 5265-1175 μg/g to CL; from 14413-90261 μg/g to K; from 3007-7091 μg/g to Mg; from 2,3-33,8 μg/g to Mn and from 5161-24973 μg/g to Na.

A comparative study of minor and trace elements in human, animal and commercial milk samples by neutron activation analysis

International Nuclear Information System (INIS)

Garg, A.N.; Weginwar, R.G.; Chutke, N.L.

1993-01-01

Human, animal (cow, buffalo and goat) and commercial milk powders (for infants and adults) have been analyzed for 5 minor (Na, K, Mg, Cl and P) and 13 trace elements (Cr, Mn, Fe, Co, Cu, Zn, Cd, Hg, As, Se, Sb, Cs and Br) by instrumental and radiochemical neutron activation. Milk standards NIST SRM 1549 and IAEA A-11 along with diet standards RM 8431a and IAEA H-9 were also analyzed for quality assurance. The method involves thermal neutron irradiation for 10 m, 1 h, 6 h and 1 week in a reactor followed by high resolution γ-spectrometry. Concentrations of Fe, Co, Zn, Sb and Se were also determined by radiochemical solvent extraction. Mean concentrations of Na, K, Mg, P, Cl, Fe, Mn and Cu in human milk (colostrum) are comparable with that of a WHO/IAEA study. It has, however, lower contents of toxic trace elements (Cr, Cd, Hg, Br, Se, Sb and As) compared to breast tissue from the same area. Cow milk is richer in Na, K, Cl, Mn and Se but it has comparable amounts of Mg, Zn, Br, Fe and Sb with respect to breast milk. Significant differences have been observed for elemental concentrations of Na, K, P and Fe in commercial formula milk powders for infants and adults. Infant's milk powders contain all the nutrient elements in balanced amounts required for the higher growth rate of a child. (author) 41 refs.; 2 figs.; 3 tabs

77 FR 21920 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Eastern...

Science.gov (United States)

2012-04-12

... was once widespread and numerous in the Medicine Bow, Pole, Snowy, and Sierra Madre Mountain Ranges... the potential for the SRM population to be its own evolutionary unit as evidenced by geographic... indicates that the SRM population is part of a more widespread evolutionary lineage that includes boreal...

Smart Rack Monitor for the Linac control system

International Nuclear Information System (INIS)

Shtirbu, S.; Goodwin, R.W.; McCrory, E.S.; Shea, M.F.

1991-01-01

The Smart Rack Monitor (SRM) is a low-cost, one board, data-acquisition module for the upgraded Linac control system at Fermilab. The SRM is based on the Motorola MC68332 microcontroller in the Business Card Computer (BCC) configuration. It is connected to the Linac local control station (to be referred to as Local Station) by an Arcnet LAN, and can be located close to the controlled hardware. Each Local Station is connected to several SRMs. The SRM has 64 A-D channels, sixteen D-A channels, and eight bytes of digital I/O on the mother board. Software Components Group's pSOS is the SRM's kernel. The SRM's software is cross-developed on VAX/VMS in C. The SRM does not have an attached console and is fully controlled by the Local Station. It performs data acquisition and settings, as directed by the Local Station. Its existence is transparent to the rest of the control system. The SRM supports code updates downloading from the VAX, through the Local Station

Determination of bismuth and cadmium after solid-phase extraction with chromosorb-107 in a syringe

International Nuclear Information System (INIS)

Tokman, Nilgun; Akman, Suleyman

2004-01-01

The determination of bismuth and cadmium by graphite furnace atomic absorption spectrometry (GFAAS) after solid-phase extraction (SPE) on Chromosorb-107 filled in a syringe was described. To retain the analytes, the sample solution treated with and without ammonium pyrolidine dithiocarbamate (APDC) was drawn into the syringe filled with Chromosorb-107 and discharged back manually. Bismuth and cadmium were quantitatively sorbed at pH ≥ 6 irrespective of whether the analyte was complexed with APDC prior to passing through the Chromosorb-107. Analyte elements sorbed on the resin were quantitatively eluted with 3.0 M of HNO 3 again drawing and discharging the eluent into the syringe and ejected it back. Optimum flow rates of sample or eluent for sorption and elution processes were 20 ml min -1 for drawing and 20 ml min -1 for discharging in all cases. Bismuth and cadmium were analyzed by graphite furnace atomic absorption spectrometry. The elements could be concentrated by drawing and discharging several portions of sample successively but eluting only one time. The validity of the proposed method was checked with standard reference materials (NIST SRM 1515 Apple-Leaves, CWW-TM-E Waste Water and CRM-SW Sea Water). The analyte elements were quantitatively (>95%) recovered from different matrices irrespective of treated samples with APDC. Detection limits (δ) were 0.8 and 1.2 μg l -1 for Bi and Cd, respectively. The method can be characterized with fastness, simplicity, quantitative recovery and high reproducibility

Numerical Simulation of Desulfurization Behavior in Gas-Stirred Systems Based on Computation Fluid Dynamics-Simultaneous Reaction Model (CFD-SRM) Coupled Model

Science.gov (United States)

Lou, Wentao; Zhu, Miaoyong

2014-10-01

A computation fluid dynamics-simultaneous reaction model (CFD-SRM) coupled model has been proposed to describe the desulfurization behavior in a gas-stirred ladle. For the desulfurization thermodynamics, different models were investigated to determine sulfide capacity and oxygen activity. For the desulfurization kinetic, the effect of bubbly plume flow, as well as oxygen absorption and oxidation reactions in slag eyes are considered. The thermodynamic and kinetic modification coefficients are proposed to fit the measured data, respectively. Finally, the effects of slag basicity and gas flow rate on the desulfurization efficiency are investigated. The results show that as the interfacial reactions (Al2O3)-(FeO)-(SiO2)-(MnO)-[S]-[O] simultaneous kinetic equilibrium is adopted to determine the oxygen activity, and the Young's model with the modification coefficient R th of 1.5 is adopted to determine slag sulfide capacity, the predicted sulfur distribution ratio LS agrees well with the measured data. With an increase of the gas blowing time, the predicted desulfurization rate gradually decreased, and when the modification parameter R k is 0.8, the predicted sulfur content changing with time in ladle agrees well with the measured data. If the oxygen absorption and oxidation reactions in slag eyes are not considered in this model, then the sulfur removal rate in the ladle would be overestimated, and this trend would become more obvious with an increase of the gas flow rate and decrease of the slag layer height. With the slag basicity increasing, the total desulfurization ratio increases; however, the total desulfurization ratio changes weakly as the slag basicity exceeds 7. With the increase of the gas flow rate, the desulfurization ratio first increases and then decreases. When the gas flow rate is 200 NL/min, the desulfurization ratio reaches a maximum value in an 80-ton gas-stirred ladle.

Automatic on-line pre-concentration system using a knotted reactor for the FAAS determination of lead in drinking water

International Nuclear Information System (INIS)

Souza, Anderson S.; Brandao, Geovani C.; Santos, Walter N.L. dos; Lemos, Valfredo A.; Ganzarolli, Edgard M.; Bruns, Roy E.; Ferreira, Sergio L.C.

2007-01-01

An automatic on-line pre-concentration system is proposed for lead determination in drinking water using flame atomic absorption spectrometry (FAAS). Lead(II) ions are retained as the 1-(2-pyridylazo)-2-naphthol (PAN) complex in the walls of a knotted reactor, followed by an elution step using 0.50 mol L -1 hydrochloric acid solution. Optimisation involving the sampling flow rate, pH and buffer concentration factors was performed using a Box-Behnken design. Other factors were established considering results of previous experiments. The procedure allows the determination of lead with a 0.43 μg L -1 detection limit (3σ/S) and precisions (expressed as relative standard deviation) of 4.84% (N = 7) and 2.9% (N = 7) for lead concentrations of 5 and 25 μg L -1 , respectively. The accuracy was confirmed by the determination of lead in the NIST SRM 1643d trace elements in natural water standard reference material. The pre-concentration factor obtained is 26.5 and the sampling frequency is 48 h -1 . The recovery achieved for lead determination in the presence of several ions demonstrated that this procedure could be applied to the analysis of drinking water samples. The method was applied for lead determination in drinking water samples collected in Jequie City, Brazil. The lead concentration found in 25 samples were always lower than the permissible maximum levels stipulated by World Health Organization

Modeling of Solar Radiation Management: A Comparison of Simulations Using Reduced Solar Constant and Stratospheric Sulphate Aerosols

Science.gov (United States)

Bala, G.; Kalidindi, S.; Modak, A.; Caldeira, K.

2014-12-01

Several climate modelling studies in the past have used reduction in solar constant to simulate the climatic effects of Solar Radiation Management (SRM) geoengineering. This is most likely valid only for space-based mirrors/reflectors but not for SRM methods that rely on stratospheric aerosols. In this study, we use a climate model to evaluate the differences in climate response to SRM by uniform solar constant reduction and stratospheric aerosols. The experiments are designed such that global mean warming from a doubling of atmospheric CO2 concentration (2xCO2) is nearly cancelled in each case. In such a scenario, the residual climate effects are similar when important surface and tropospheric climate variables such as temperature and precipitation are considered. However, there are significant differences in stratospheric temperature response and diffuse and direct radiation reaching the surface. A difference of 1K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods, with warming in the aerosol scheme and a slight cooling for sunshades. While the global mean surface diffuse radiation increases by ~23% and direct radiation decreases by about 9% in the case of aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~1.0%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 1.8 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 15.2% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 8%) and NPP (~3%) relative to 2xCO2, indicating the negligible effect of the fractional changes in direct/diffuse radiation on the overall plant productivity. Based on our modelling study, we conclude that the climate states produced by a

ATAQS: A computational software tool for high throughput transition optimization and validation for selected reaction monitoring mass spectrometry

Directory of Open Access Journals (Sweden)

Ramos Hector

2011-03-01

Full Text Available Abstract Background Since its inception, proteomics has essentially operated in a discovery mode with the goal of identifying and quantifying the maximal number of proteins in a sample. Increasingly, proteomic measurements are also supporting hypothesis-driven studies, in which a predetermined set of proteins is consistently detected and quantified in multiple samples. Selected reaction monitoring (SRM is a targeted mass spectrometric technique that supports the detection and quantification of specific proteins in complex samples at high sensitivity and reproducibility. Here, we describe ATAQS, an integrated software platform that supports all stages of targeted, SRM-based proteomics experiments including target selection, transition optimization and post acquisition data analysis. This software will significantly facilitate the use of targeted proteomic techniques and contribute to the generation of highly sensitive, reproducible and complete datasets that are particularly critical for the discovery and validation of targets in hypothesis-driven studies in systems biology. Result We introduce a new open source software pipeline, ATAQS (Automated and Targeted Analysis with Quantitative SRM, which consists of a number of modules that collectively support the SRM assay development workflow for targeted proteomic experiments (project management and generation of protein, peptide and transitions and the validation of peptide detection by SRM. ATAQS provides a flexible pipeline for end-users by allowing the workflow to start or end at any point of the pipeline, and for computational biologists, by enabling the easy extension of java algorithm classes for their own algorithm plug-in or connection via an external web site. This integrated system supports all steps in a SRM-based experiment and provides a user-friendly GUI that can be run by any operating system that allows the installation of the Mozilla Firefox web browser. Conclusions Targeted

A Bearingless Switched-Reluctance Motor for High Specific Power Applications

Science.gov (United States)

Choi, Benjamin B.; Siebert, Mark

2006-01-01

A 12-8 switched-reluctance motor (SRM) is studied in bearingless (or self-levitated) operation with coil currents limited to the linear region to avoid magnetic saturation. The required motoring and levitating currents are summed and go into a single motor coil per pole to obtain the highest power output of the motor by having more space for motor coil winding. Two controllers are investigated for the bearingless SRM operation. First, a model-based controller using the radial force, which is adjusted by a factor derived from finite element analysis, is presented. Then a simple and practical observation-based controller using a PD (proportional-derivative) control algorithm is presented. Both controllers were experimentally demonstrated to 6500 rpm. This paper reports the initial efforts toward eventual self levitation of a SRM operating into strong magnetic core saturation at liquid nitrogen temperature.

An Internal Thermal Environment Model of an Aluminized Solid Rocket Motor with Experimental Validation

Science.gov (United States)

Martin, Heath T.

2015-01-01

Due to the severity of the internal solid rocket motor (SRM) environment, very few direct measurements of that environment exist; therefore, the appearance of such data provides a unique opportunity to assess current thermal/fluid modeling capabilities. As part of a previous study of SRM internal insulation performance, the internal thermal environment of a laboratory-scale SRM featuring aluminized propellant was characterized with two types of custom heat-flux calorimeters: one that measured the total heat flux to a graphite slab within the SRM chamber and another that measured the thermal radiation flux. Therefore, in the current study, a thermal/fluid model of this lab-scale SRM was constructed using ANSYS Fluent to predict not only the flow field structure within the SRM and the convective heat transfer to the interior walls, but also the resulting dispersion of alumina droplets and the radiative heat transfer to the interior walls. The dispersion of alumina droplets within the SRM chamber was determined by employing the Lagrangian discrete phase model that was fully coupled to the Eulerian gas-phase flow. The P1-approximation was engaged to model the radiative heat transfer through the SRM chamber where the radiative contributions of the gas phase were ignored and the aggregate radiative properties of the alumina dispersion were computed from the radiative properties of its individual constituent droplets, which were sourced from literature. The convective and radiative heat fluxes computed from the thermal/fluid model were then compared with those measured in the lab-scale SRM test firings and the modeling approach evaluated.

Early Forming a Hummingbird-like Hovering Neural Network Circuitry Pattern with Reentrant Spatiotemporal Energy-Sensory Orientation Privileged to Avoid “Epilepsy” Based on a Biomimetic Acetylcholinesterase Memcapacitor Prosthesis

Directory of Open Access Journals (Sweden)

Ellen T. Chen

2015-08-01

Full Text Available The hummingbird’s significant asymmetry hovering flight with energy conservation pattern is remarkable among all vertebrates. However, little is known to human’s neuronal network circuitry current flow pattern for whether or not has this privilege during slow wave sleeping (SWS. What is the advantage in order to avoid diseases if we have this network pattern ? A memory device was developed with nanostructured biomimetic acetylcholinesterase (ACHE gorge membrane on gold chips as memcapacitor 1, served as a normal brain network prosthesis, compared with a mutated ACHE prosthesis as device 2, for evaluation of neuronal network circuitry integrity in the presence of Amyloid- beta (Ab under the conditions of free from tracers and antibodies in spiked NIST SRM 965A human serum. Three categories of Reentrant Energy-Sensory images are presented based on infused brain pulse energies in a matrix of “Sensory Biomarkers” having frequencies over 0.25-333 Hz at free and fixed Ab levels, respectively. Early non-symptomatic epilepsy was indentified and predicted by device 2 due to Pathological High Frequency Oscillation (pHFO and large areas of 38 µM Ab re-depositions. Device 1 sensitively “feels” Ab damage because of its Frequency Oscillation (HFO enhanced the hummingbird- like hovering pattern with higher reentrant energy sensitivity of 0.12 pj/bit/s/µm3 without Ab compared with Ab, 13 aj/bit/s/µm3/nM over 3.8-471 nM range over 0.003-4s. Device 1 reliably detected early CR dysfunction privileged to avoid epilepsy.

FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System

Directory of Open Access Journals (Sweden)

Yan-yang Wang

2014-01-01

Full Text Available The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV. The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.

Estimating the Global Agricultural Impact of Solar Radiation Management using Volcanic Eruptions as Natural Experiments

Science.gov (United States)

Proctor, J.; Hsiang, S. M.; Burney, J. A.; Burke, M.; Schlenker, W.

2017-12-01

Solar radiation management (SRM) is increasingly considered an option for managing global temperatures, yet the economic impacts of ameliorating climatic changes by scattering sunlight back to space remain largely unknown. Though SRM may increase crop yields by reducing heat stress, its impacts from concomitant changes in available sunlight have never been empirically estimated. Here we use the volcanic eruptions that inspired modern SRM proposals as natural experiments to provide the first estimates of how the stratospheric sulfate aerosols (SS) created by the eruptions of El Chichon and Pinatubo altered the quantity and quality of global sunlight, how those changes in sunlight impacted global crop yields, and the total effect that SS may have on yields in an SRM scenario when the climatic and sunlight effects are jointly considered. We find that the sunlight-mediated impact of SS on yields is negative for both C4 (maize) and C3 (soy, rice, wheat) crops. Applying our yield model to a geoengineering scenario using SS-based SRM from 2050-2069, we find that SRM damages due to scattering sunlight are roughly equal in magnitude to SRM benefits from cooling. This suggests that SRM - if deployed using SS similar to those emitted by the volcanic eruptions it seeks to mimic - would attenuate little of the damages from climate change to global agriculture on net. Our approach could be extended to study SRM impacts on other global systems, such as human health or ecosystem function.

Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs.

Science.gov (United States)

Turk, G C; Yu, L L; Salit, M L; Guthrie, W F

2001-06-01

Multielement analyses of environmental reference materials have been performed using existing certified reference materials (CRMs) as calibration standards for inductively coupled plasma-mass spectrometry. The analyses have been performed using a high-performance methodology that results in comparison measurement uncertainties that are significantly less than the uncertainties of the certified values of the calibration CRM. Consequently, the determined values have uncertainties that are very nearly equivalent to the uncertainties of the calibration CRM. Several uses of this calibration transfer are proposed, including, re-certification measurements of replacement CRMs, establishing traceability of one CRM to another, and demonstrating the equivalence of two CRMs. RM 8704, a river sediment, was analyzed using SRM 2704, Buffalo River Sediment, as the calibration standard. SRM 1632c, Trace Elements in Bituminous Coal, which is a replacement for SRM 1632b, was analyzed using SRM 1632b as the standard. SRM 1635, Trace Elements in Subbituminous Coal, was also analyzed using SRM 1632b as the standard.

Post hoc interlaboratory comparison of single particle ICP-MS size measurements of NIST gold nanoparticle reference materials.

Science.gov (United States)

Montoro Bustos, Antonio R; Petersen, Elijah J; Possolo, Antonio; Winchester, Michael R

2015-09-01

Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is an emerging technique that enables simultaneous measurement of nanoparticle size and number quantification of metal-containing nanoparticles at realistic environmental exposure concentrations. Such measurements are needed to understand the potential environmental and human health risks of nanoparticles. Before spICP-MS can be considered a mature methodology, additional work is needed to standardize this technique including an assessment of the reliability and variability of size distribution measurements and the transferability of the technique among laboratories. This paper presents the first post hoc interlaboratory comparison study of the spICP-MS technique. Measurement results provided by six expert laboratories for two National Institute of Standards and Technology (NIST) gold nanoparticle reference materials (RM 8012 and RM 8013) were employed. The general agreement in particle size between spICP-MS measurements and measurements by six reference techniques demonstrates the reliability of spICP-MS and validates its sizing capability. However, the precision of the spICP-MS measurement was better for the larger 60 nm gold nanoparticles and evaluation of spICP-MS precision indicates substantial variability among laboratories, with lower variability between operators within laboratories. Global particle number concentration and Au mass concentration recovery were quantitative for RM 8013 but significantly lower and with a greater variability for RM 8012. Statistical analysis did not suggest an optimal dwell time, because this parameter did not significantly affect either the measured mean particle size or the ability to count nanoparticles. Finally, the spICP-MS data were often best fit with several single non-Gaussian distributions or mixtures of Gaussian distributions, rather than the more frequently used normal or log-normal distributions.

Assessment of trace element contents of chicken products from turkey

International Nuclear Information System (INIS)

Uluozlu, Ozgur Dogan; Tuzen, Mustafa; Mendil, Durali; Soylak, Mustafa

2009-01-01

Due to the consumption of chicken and chicken products in Turkey at high ratio, trace metal content of chicken and chicken products from Turkey were determined by atomic absorption spectrometry after microwave digestion. The accuracy of the method was confirmed by analysis of standard reference material (NIST SRM 1577b Bovine liver). Trace element content in various parts of chicken samples and chicken products were to be in the range of 0.10-114 μg/g for copper, 0.25-6.09 μg/kg for cadmium, 0.01-0.40 μg/g for lead, 0.10-0.91 μg/g for selenium, 0.05-3.91 μg/g for manganese, 0.06-0.10 μg/g for arsenic, 0.01-0.72 μg/g for chromium, 0.01-2.08 μg/g for nickel, 0.01-0.02 μg/g for cobalt, 0.10-1.90 μg/g for aluminium, 1.21-24.3 μg/g for zinc, 2.91-155 μg/g for iron. The levels of lead in some analyzed chicken products were higher than the recommended legal limits for human consumption

A practical guide for the design and implementation of the double-spike technique for precise determination of molybdenum isotope compositions of environmental samples.

Science.gov (United States)

Skierszkan, E K; Amini, M; Weis, D

2015-03-01

The isotopic double-spike method allows for the determination of stable isotope ratios by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with accuracy and precision in the range of ∼0.02 ‰ amu(-1), but its adoption has been hindered by the perceived difficulties in double-spike calibration and implementation. To facilitate the implementation of the double-spike approach, an explanation of the calibration and validation of a (97)Mo-(100)Mo double-spike protocol is given in more detail than has been presented elsewhere. The long-term external standard reproducibility is 0.05 ‰ on δ(98/95)Mo measurements of standards. δ(98/95)Mo values for seawater and U.S. Geological Survey (USGS) reference materials SDO-1 and BCR-2 measured in this study are 2.13 ± 0.04 ‰ (2 SD, n = 3), 0.79 ± 0.05 ‰ (2 SD, n = 11), and -0.04 ± 0.10 ‰ (2 SD, n = 3) relative to the NIST-SRM-3134. The double-spike method corrects for laboratory and instrumental fractionation which are not accounted for using other mass bias correction methods. Spike/sample molar ratios between 0.4 and 0.8 provide accurate isotope measurements; outside of this range, isotope measurements are inaccurate but corrections are possible when standards and samples are spiked at a similar ratio.

Decomposição de amostras de solos assistida por radiação microondas: estratégia para evitar a formação de fluoretos insolúveis Microwave-assisted decomposition of soil samples: strategies to avoid formation of insoluble fluoride salts

Directory of Open Access Journals (Sweden)

Edivan Carvalho Vieira

2005-07-01

Full Text Available A decomposição de amostras que contêm elevados teores de Si, utilizando mistura com os ácidos nítrico e fluorídrico, pode provocar a precipitação de fluoretos de Al(III, Ca(II, Fe(III e Mg(II durante a digestão, impedindo a recuperação total desses elementos. Visando minimizar esse problema, foram testados quatro procedimentos aplicados a diferentes amostras de solos. O procedimento mais eficiente envolveu a decomposição assistida por radiação microondas, seguida pela separação do material sólido residual com elevado teor de Si do sobrenadante ácido. A fração residual foi solubilizada usando HF concentrado e, após complexação com ácido bórico, essa solução foi misturada à fase líquida do digerido. Os teores de metais nos digeridos foram determinados por espectrometria de emissão óptica em plasma induzido (ICP OES e a exatidão foi demonstrada aplicando o procedimento proposto em amostras provenientes do programa colaborativo International Soil-Analytical Exchange (ISE, Wegening Agricultural University, Holanda e em amostra certificada de solo proveniente do National Institute of Standard and Technology (NIST, SRM 2709, que apresentou respectivamente, os seguintes percentuais de recuperação: 100,0 ± 2,6; 99,5 ± 1,9; 108,5 ± 2,7; 94,6 ± 8,9; 92,2 ± 9,7; 95,7 ± 1,8; 96,7 ± 2,7; 95,2 ± 0,6; 103,6 ± 2,6 e 96,1 ± 1,6 para, Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, V e Zn.The use of pre-mixed nitric and hydrofluoric acids for the decomposition of samples containing high amounts of Si can cause the precipitation of Al(III, Ca(II, Fe(III, and Mg(II fluorides during digestion, reducing the total recovery of these elements. Four procedures were applied to certified soil samples in an attempt to circumvent this problem. The most efficient procedure was based on microwave-assisted acid digestion decomposition of the samples, followed by separation of the residual silicate compounds. This fraction was solubilized using

Determination of selenium status using the nail biologic monitor in a canine model

International Nuclear Information System (INIS)

Steven Morris, J.; Spate, V.L.; Ruth Ann Ngwenyama; Waters, D.J.

2012-01-01

Toenails and fingernails are routinely used to estimate selenium status in epidemiological studies; however, literature validating nail selenium concentration as a surrogate for critical organs is limited. In this study diets of intact male dogs were selenium supplemented at two physiological levels (3 and 6 μg/kg/day) in two different forms, selenomethionine and selenium-enriched bioformed yeast. The selenium-adequate basal diet consumed by the treatment and control groups during the 4-week run-in period and throughout the trial contained 0.3 ppm selenium. After 7 months the dogs in the two treatment groups and the control group were euthanized. Representative tissue samples from prostate, brain, liver, heart and skeletal muscle were collected, rinsed and frozen. Toenail clippings from multiple toes were also collected. Selenium was determined by neutron activation analysis using Se77m (half life = 17.4 s) at the University of Missouri Research Reactor Center. NIST SRM 1577, Bovine Liver was analyzed as a quality control. The analysts were blinded to control and treatment group assignments. As expected, tissue selenium levels increased proportionally with supplementation. A slightly greater increase in tissue selenium was observed for the purified selenomethionine compared to the bioformed yeast; however this trend was significant only for brain tissue. Toenail selenium concentrations and tissue selenium were highly correlated (p < 0.003) with Pearson coefficients of 0.759 (skeletal muscle), 0.745 (heart), 0.729 (brain), 0.723 (prostate), and 0.632 (liver). The toenail biologic monitor accurately assesses selenium status in skeletal muscle, heart, brain, prostate, and liver in the canine model. (author)

Some aspects of cross-border cooperation in euroregions of the Czech Republic on example of the Šumava region

Czech Academy of Sciences Publication Activity Database

Cetkovský, Stanislav; Klusáček, Petr; Martinát, Stanislav; Zapletalová, Jana

2007-01-01

Roč. 15, č. 1 (2007), s. 43-55 ISSN 1210-8812 R&D Projects: GA AV ČR IAA7118301 Institutional research plan: CEZ:AV0Z30860518 Keywords : Euroregions * cross-border cooperation * Šumava * regional development * environmental protection * Czech Republic Subject RIV: DE - Earth Magnetism, Geodesy, Geography

Epidemiology of Nonfatal Injuries among Schoolchildren

Science.gov (United States)

ALBashtawy, Mohammed; Al-Awamreh, Khetam; Gharaibeh, Huda; Al-Kloub, Manal; Batiha, Abdul-Monim; Alhalaiqa, Fadwa; Hamadneh, Shereen

2016-01-01

Nonfatal injuries are considered as one of the major public health hazards affecting schoolchildren, and the majority of these injuries occur at school or in the home. A cross-sectional study was conducted over a period of 3 months, March-May 2015. The participants were 4,355 Jordanian schoolchildren in Grades 7-12. The Pearson ?[superscript 2]…

Bias in the absorption coefficient determination of a fluorescent dye, standard reference material 1932 fluorescein solution