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Sample records for 226ra standard solution

  1. Removal of 226Ra and 228Ra from TENORM sludge waste using surfactants solutions.

    PubMed

    Attallah, M F; Hamed, Mostafa M; El Afifi, E M; Aly, H F

    2015-01-01

    The feasibility of using surfactants as extracting agent for the removal of radium species from TENORM sludge produced from petroleum industry is evaluated. In this investigation cationic and nonionic surfactants were used as extracting agents for the removal of radium radionuclides from the sludge waste. Two surfactants namely cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX100) were investigated as the extracting agents. Different parameters affecting the removal of both (226)Ra and (228)Ra by the two surfactants as well as their admixture were studied by the batch technique. These parameters include effect of shaking time, surfactants concentration and temperature as well as the effect of surfactants admixture. It was found that, higher solution temperature improves the removal efficiency of radium species. Combined extraction of nonionic and cationic surfactants produces synergistic effect in removal both (226)Ra and (228)Ra, where the removals reached 84% and 80% for (226)Ra and (228)Ra, respectively, were obtained using surfactants admixture.

  2. Radium uptake during barite recrystallization at 23 ± 2 °C as a function of solution composition: An experimental 133Ba and 226Ra tracer study

    NASA Astrophysics Data System (ADS)

    Curti, E.; Fujiwara, K.; Iijima, K.; Tits, J.; Cuesta, C.; Kitamura, A.; Glaus, M. A.; Müller, W.

    2010-06-01

    High-purity synthetic barite powder was added to pure water or aqueous solutions of soluble salts (BaCl 2, Na 2SO 4, NaCl and NaHCO 3) at 23 ± 2 °C and atmospheric pressure. After a short pre-equilibration time (4 h) the suspensions were spiked either with 133Ba or 226Ra and reacted under constant agitation during 120-406 days. The pH values ranged from 4 to 8 and solid to liquid (S/L) ratios varied from 0.01 to 5 g/l. The uptake of the radiotracers by barite was monitored through repeated sampling of the aqueous solutions and radiometric analysis. For both 133Ba and 226Ra, our data consistently showed a continuous, slow decrease of radioactivity in the aqueous phase. Mass balance calculations indicated that the removal of 133Ba activity from aqueous solution cannot be explained by surface adsorption only, as it largely exceeded the 100% monolayer coverage limit. This result was a strong argument in favor of recrystallization (driven by a dissolution-precipitation mechanism) as the main uptake mechanism. Because complete isotopic equilibration between aqueous solution and barite was approached or even reached in some experiments, we concluded that during the reaction all or substantial fractions of the initial solid had been replaced by newly formed barite. The 133Ba data could be successfully fitted assuming constant recrystallization rates and homogeneous distribution of the tracer into the newly formed barite. An alternative model based on partial equilibrium of 133Ba with the mineral surface (without internal isotopic equilibration of the solid) could not reproduce the measured activity data, unless multistage recrystallization kinetics was assumed. Calculated recrystallization rates in the salt solutions ranged from 2.8 × 10 -11 to 1.9 × 10 -10 mol m -2 s -1 (2.4-16 μmol m -2 d -1), with no specific trend related to solution composition. For the suspensions prepared in pure water, significantly higher rates (˜5.7 × 10 -10 mol m -2 s -1 or ˜49 μmol m

  3. A correlation between soil descriptions and {sup 226}Ra concentrations in Florida soils

    SciTech Connect

    Harrison, D.P.

    1992-12-31

    The soil radium content in Florida is highly variable. The range in radium concentrations, where the samples involved in this study are concerned, is from 0.1 pCi/g to 18.5 pCi/g. Low {sup 226}Ra concentrations (0.1 to 5 pCi/g) are evidenced in sands, moderate concentrations (5 to 11 pCi/g) are found in silt and gravel, and high {sup 226}Ra concentrations (>11 pCi/g) are found in soil horizons with shell, clay, and strata with phosphate. Strata containing phosphate yields a high concentration of {sup 226}Ra. The information obtained in this study, soil descriptions with their corresponding {sup 226}Ra concentrations, comes from geological cores drilled by geotechnical consultants with gamma spectrometry analysis performed by high resolution gamma spectroscopy. Concentration; of {sup 226}Ra generally increase with depth. These cores are usually terminated at 20 feet deep, with some cores being shallower than this due to hitting bedrock or encountering the water table. These frequency distributions give the core-logging geologist an approximate concentration of {sup 226}Ra based on the description of the soil. Since the correlation of {sup 226}Ra and soil descriptions can be used as a tool in assigning indoor radon potential, this study is of importance to land managers, contractors, developers, and regulating agencies who are attempting to place standards on tracts of land with {sup 226}Ra concentration used as a criterion.

  4. 226Ra bioavailability to plants at the Urgeiriça uranium mill tailings site.

    PubMed

    Madruga, M J; Brogueira, A; Alberto, G; Cardoso, F

    2001-01-01

    Large amounts of solid wastes (tailings) resulting from the exploitation and treatment of uranium ore at the Urgeiriça mine (north of Portugal) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment, some dams were revegetated with eucalyptus (Eucalyptus globolus) and pines (Pinus pinea). Besides these plants, some shrubs (Cytisus spp.) are growing in some of the dams. The objective of this study is to determine the 226Ra bioavailability from uranium mill tailings by quantifying the total and available fraction of radium in the tailings and to estimate its transfer to plants growing on the tailing piles. Plant and tailing samples were randomly collected and the activity concentration of 226Ra in plants (aerial part and roots) and tailings was measured by gamma-spectrometry. The exchangeable fraction of radium in tailings was quantified using one single step extraction with 1 mol dm-3 ammonium acetate (pH = 7) or 1 mol dm-3 calcium chloride solutions. The results obtained for 226Ra uptake by plants show that 226Ra concentration ratios for eucalyptus and pines decrease at low 226Ra concentrations in the tailings and appear relatively constant at higher radium concentrations. For shrubs, the concentration ratios increase at higher 226Ra solid waste concentrations approaching a saturation value. Percentage values of 16.0 +/- 8.3 and 12.9 +/- 8.9, for the fraction of radium extracted from the tailings, using 1 mol dm-3 ammonium acetate or calcium chloride solutions, respectively, were obtained. The 226Ra concentration ratios determined on the basis of exchangeable radium are one order of magnitude higher than those based on total radium. It can be concluded that, at a 95% confidence level, more consistent 226Ra concentration ratios were obtained when calculated on the basis of available radium than when total radium was considered, for all the dams.

  5. Sorption of (226)Ra from oil effluents onto synthetic cation exchangers.

    PubMed

    Al Attar, Lina; Safia, Bassam

    2013-07-30

    Increasing environmental awareness is being urged for the safe disposal of (226)Ra-contaminated production water generated in the oil industry. Birnessite, antimony silicate and their cationic derivatives were studied for the take-up of (226)Ra using the batch-type method under experimentally determined parameters, viz. contact time, solution-solid ratio and (226)Ra concentration. Data was expressed in terms of distribution coefficients. Sorption experiments were performed in different concentrations of nitric acid in order to speculate the mechanism of (226)Ra uptake. Variation in the magnitude of sorption efficiency of the materials in the presence of the major components of waste streams, i.e. Na(+), K(+) and Ca(2+), revealed that K(+) was the greatest competitor and Na(+) the least. The application of the materials to sorb (226)Ra from actual oil co-production water samples, collected from Der Ezzor and Al Fourat petroleum companies (DEZPC and AFPC), was interpreted in terms of the exchange properties of the materials and water characterisation. Of the parameters studied, the selectivity of materials was shown to be greatly dependent on the pH of wastewater to be treated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. 226Ra determination in phosphogypsum by alpha-particle spectrometry

    NASA Astrophysics Data System (ADS)

    Aguado, J. L.; Bolívar, J. P.; García-Tenorio, R.

    1999-01-01

    A radiochemical method for226Ra determination by alpha-particle spectrometry in environmental samples has been developed in our laboratory. The method has been validated by measurements in samples with known concentrations of this radionuclide and it has been applied in studies related to226Ra behaviour in phosphogypsum (the main by-product of producing phosphoric acid from phosphate rocks).

  7. Occurrence of 226Ra in Ground Waters From a Granitic Aquifer at the City of Itatiba, Eastern Sao Paulo State, Brazil

    NASA Astrophysics Data System (ADS)

    Santos, R. N.; Lucas, F. D.; Brenha Ribeiro, F.

    2007-05-01

    Among the naturally occurring radionuclides, 226Ra play an important role in establishing the ground water radioactivity level. In this work, it is presented the 226Ra activity concentration measured in ground water drawn from a granitic fractured aquifer at the Ribeira Folded Belt, eastern Sao Paulo State, Brazil. The ground water samples were collected twice in the same well in June, 2nd and July 6th, 2005. After discarding about fifteen minutes of continuous well pumping, ground waters samples are collected in 50 L polyethylene containers, previously conditioned with nitric acid, 0.03 mol/L. The water temperature, pH and Eh are measured at the sampling site. The water samples were preserved by addition of 2.0 mL of concentrated nitric acid to lower its pH to less than 2. In laboratory, three 20 L aliquots were selected for independent radiochemical processing. Radium is precipitated from water samples in the form of barium-radium sulfate. The barium-radium precipitate is filtered and dried over the filter paper. The radium containing filter is then sealed with an adhesive plastic film and hermetically closed in a rigid polystyrene sample holder. The sample is left at rest for at least 40 days to allow the short lived daughters (222Rn, 214Pb and 214Bi) reach secular radioactive equilibrium with 226Ra. The radium activity is then indirectly measured by gamma-ray spectrometry through the full absorption peaks from the 214Pb and 214Bi. The gamma-ray spectrometry activity measurements are made by comparison with 226Ra standards. These standards were prepared by the radium precipitation from secondary standard solutions obtained by dilution of a (19.52 +/- 0.72) Bq/g 226Ra solution. The precipitate standards were prepared following the procedure adopted for the ground water samples. The observed 226Ra activity concentration were (43 +/- 2) mBq/L and (46 +/- 3) mBq/L, for the first and second water sampling campaigns, respectively.

  8. 226Ra measurement in Mo, Cd and Nd 2O 3 samples with the emanation method

    NASA Astrophysics Data System (ADS)

    Barabash, A. S.; Barabanov, I. R.; Kornoukhov, V. N.; Orekhov, I. V.

    2001-08-01

    Measurements of 226Ra content in materials and chemical reagents used to construct the double beta decay sources in the NEMO-3 experiment have been done with the emanation method technique. Three different radon emanation technologies were used in these studies. The first was the "traditional" method of dissolving the sample. The second was an extraction of Rn from a melted sample and finally a technique of heating fine-grained powder was used. It is shown that there is good agreement of the data received with the emanation method and low background high purity germanium detectors. The sensitivity of this method is 0.02 mBq/ l of solution (for the "standard" emanation method) or 0.02 mBq/ kg (for methods in which radon is extracted from a powder or melt).

  9. Leaching of 226Ra from components of uranium mill tailings

    USGS Publications Warehouse

    Landa, E.R.

    1991-01-01

    A sequential extraction procedure was used to characterize the geochemical forms of 226Ra retained by mixtures of quartz sand and a variety of fine-grained rock and mineral species. These mixtures had previously been exposed to the sulfuric acid milling liquor of a simulated acid-leach uranium milling circuit. For most test cases, the major fraction of the 226Ra was extracted with 1 mol/1 NH4Cl and was deemed to be exchangeable. However, 226Ra retained by the barite-containing mixture was resistant to both 1 mol/1 NH4Cl and 1 mol/HCHCl extraction. ?? 1991.

  10. Concentration of {sup 226}Ra in human teeth

    SciTech Connect

    Yamamoto, Masayoishi; Ueno, Kaoru; Hinoide, Moriyo; Ohkubo, Yoshiteru

    1994-11-01

    {sup 226}Ra concentrations in human teeth from several cities, mainly Tokyo, Japan, were determined with emphasis on the measurement of low-level {sup 226}Ra by alpha-ray spectrometry following chemical separation. No appreciable differences in {sup 226}Ra concentration were found among various permanent teeth samples of different age groups in Tokyo. The mean {sup 226}Ra concentration for Tokyo was 0.51 {+-} 0.06 mBq (g CA){sup -1}. {sup 226}Ra concentration [mean: 0.67 {+-} 0.11 mBq (g Ca){sup -1}] in teeth in western regions of the country was statistically higher than that [mean: 0.48 {+-} 0.09 mBq (g Ca){sup -1}] in eastern ones. The mean {sup 226}Ra concentration [0.51 mBq (g CA){sup -1}] in teeth from Tokyo was less than the concentration [1.11 mBq (g CA){sup -1}] reported for vertebral bone samples of this city. 27 refs., 1 fig., 5 tabs.

  11. 226Ra and 228Ra in Iowa drinking water.

    PubMed

    Kriege, L B; Hahne, R M

    1982-10-01

    The University Hygienic Laboratory has been performing radiochemical analyses on drinking water in the state of Iowa for over 20 yr. Approximately one half of the 1250 community water supplies that exist in Iowa have been sampled roughly once every 3 yr for the past decade. Originally, raw and finished waters that showed a gross alpha activity of greater than or equal to 3.0 pCi/L were analyzed for 226Ra, but starting in July 1976, finished waters were analyzed for both 226Ra and 228Ra if the gross alpha activity was greater than or equal to 2.0 pCi/L. As of 10 June 1981, 604 community water supplies had submitted composited samples that have been analyzed for gross alpha, 226Ra, and 228Ra concentrations in compliance with the federal Safe Drinking Water Act (Public Law 93-523). Approximately 10% of these supplies were found to exceed the EPA-established maximum contaminant level (MCL) for 226Ra plus 228Ra of 5 pCi/L. The results revealed, consistent with several other investigators (Mc81; Mi80; Mic80), that some supplies had higher concentrations of 228Ra than of 226Ra. It was also concluded, in agreement with McCurdy and Mellor (Mc81), that some ground water samples cannot be accurately measured for gross alpha activity due to their high dissolved solids content.

  12. Rapid determination of 226Ra in emergency urine samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; ...

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed.more » The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.« less

  13. 226Ra or 226Ra/Ba dating of Holocene volcanic rocks: application to Mt. Etna and Merapi volcanoes

    NASA Astrophysics Data System (ADS)

    Condomines, M.; Gauthier, P. J.; Tanguy, J. C.; Gertisser, R.; Thouret, J. C.; Berthommier, P.; Camus, G.

    2005-02-01

    This paper shows how 226Ra- 230Th disequilibria can be used to date Holocene volcanic rocks from some well selected volcanoes. A systematic study of these disequilibria on historical or well-dated volcanic samples is indeed first required to test the applicability of this method. Two examples are described here to illustrate its potential. In the case of Mt. Etna, the good correlation observed between ( 226Ra) 0 activities at the time of eruption and Th contents in lava flows from the last two millennia [M. Condomines, J.C. Tanguy, V. Michaud, Magma dynamics at Mt. Etna: constraints from U-Th-Ra-Pb radioactive disequilibria and Sr isotopes in historical lavas, Earth Planet. Sci. Lett. 132 (1995) 25-41] is used to infer the ages of several newly analysed lava flows. The calculated ages are in good agreement with those deduced from the archaeomagnetic curve describing the variation of the geomagnetic field direction in southern Italy [J.C. Tanguy, I. Bucur, J.F.C. Thompson, Geomagnetic secular variation in Sicily and revised ages of historic lavas from Mt. Etna, Nature 318 (1985) 453-455, J.C. Tanguy, M. Le Goff, V. Chillemi, A. Paiotti, C. Principe, S. La Delfa, G. Patane, Variation séculaire de la direction du champ géomagnétique enregistrée par les laves de l'Etna et du Vésuve pendant les deux derniers millénaires, C. R. Acad. Sci. Paris 329 (1999) 557-564, J.C. Tanguy, M. Le Goff, C. Principe, S. Arrighi, V. Chillemi, A. Paiotti, S. La Delfa, G. Patane, Archaeomagnetic dating of Mediterranean volcanics of the last 2100 years: validity and limits. Earth Planet. Sci. Lett. 211 (2003) 111-124]. We also present a whole set of new U-series data on historical, recent, and older samples from Merapi (Indonesia), and show that the ( 226Ra)/Ba ratio has probably maintained a quasi-steady state value during at least the past four millennia, and can be used to infer the ( 226Ra) 0/Ba ratio of old volcanics at the time of eruption, and thus their ages. Comparison with

  14. 230Th, 226Ra and 222Rn in abyssal sediments

    NASA Astrophysics Data System (ADS)

    Kadko, David

    1980-09-01

    A model that predicts the flux of 222Rn out of deep-sea sediment is presented. The radon is ultimately generated by 230Th which is stripped from the overlying water into the sediment. Data from many authors are compared with the model predictions. It is shown that the continental contribution of ionium is not significant, and that at low sedimentation rates, biological mixing and erosional processes strongly affect the surface concentration of the ionium. Two cores from areas of slow sediment accumulation, one from a manganese nodule region of the central Pacific and one from the Rio Grande Rise in the Atlantic were analyzed at closely spaced intervals for 230Th, 226Ra, and 210Pb. The Pacific core displayed evidence of biological mixing down to 12 cm and had a sedimentation rate of only 0.04 cm/kyr. The Atlantic core seemed to be mixed to 8 cm and had a sedimentation rate of 0.07 cm/kyr. Both cores had less total excess 230Th than predicted. Radium sediment profiles are generated from the 230Th model. Adsorbed, dissolved, and solid-phase radium is considered. According to the model, diffusional losses of radium are especially important at low sedimentation rates. Any particulate, or excess radium input is ignored in this model. The model fits the two analyzed cores if the fraction of total radium available for adsorption-desorption is about 0.5-0.7, and if K, the distribution coefficient, is about 1000. Finally, the flux of radon out of the sediments is derived from the model-generated radium profiles. It is shown that the resulting standing crop of 222Rn in the overlying water may be considered as an added constraint in budgeting 230Th and 226Ra in deep-sea sediments.

  15. Study of the occurrence of 222Rn and 226Ra in drinking water in Spain.

    PubMed

    Soto, J; Fernández, P L; Gómez, J; Ródenas, C

    1995-12-01

    With the aim of determining the contribution of water to the background of natural radiation in Spain, the 222Rn concentration levels were measured in domestic drinking water from a large part of the country. The water analyzed, both surface and groundwater, was collected in two areas of very distinct geological characteristics, pre-selected for the likelihood of their containing high levels of 222Rn. This water was measured using a coaxial detector of high purity Ge. The overall results demonstrate a log-normal distribution of 222Rn levels, with a geometric and arithmetic means of 10 and 381 Bq L-1, respectively, and a range between detection limit of 2 Bq L-1 and a maximum of 31,000 Bq L-1. The 222Rn concentrations measured in surface water are generally below the detection limit. Significant differences have been found depending on the geological characteristics of the area of reference, although the very distinct concentration levels of 222Rn found in samples of similar lithology imply the influence of more complex factors in the solution of 222Rn in water. Due to the relationship between radon and 226Ra, the concentration of the latter was measured in the same water using radiochemical separation and a scintillation ZnS(Ag) detector. No significant correlation between 226Ra and 222Rn concentrations has been observed unless measurements carried out in a high background radiation region are considered separately.

  16. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    DOE PAGES

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; ...

    2016-03-24

    A new method that rapidly preconcentrates and measures 226Ra from hydraulic fracturing wastewater samples was developed in the Savannah River Environmental Laboratory. The method improves the quality of 226Ra measurements using gamma spectrometry by providing up to 100x preconcentration of 226Ra from this difficult sample matrix, which contains very high levels of calcium, barium, strontium, magnesium and sodium. The high chemical yield, typically 80-90%, facilitates a low detection limit, important for lower level samples, and indicates method ruggedness. Ba-133 tracer is used to determine chemical yield and correct for geometry-related counting issues. The 226Ra sample preparation takes < 2 hours.

  17. (228)Ra and (226)Ra measurement on a BaSO4 co-precipitation source.

    PubMed

    Medley, Peter; Martin, Paul; Bollhöfer, Andreas; Parry, David

    2014-10-14

    One of the most commonly-used methods for determination of (226)Ra, particularly in water samples, utilises co-precipitation of Ra with BaSO4, followed by microfiltration to produce a source for alpha counting. This paper describes two extensions to BaSO4 co-precipitation methods which enable determination of (228)Ra using the same source. The adaptations presented here do not introduce any contaminants that will affect the separation of radium or alpha counting for (226)Ra, and can be used for re-analysis of already existing sources prepared by BaSO4 co-precipitation. The first adaptation uses detection of (228)Ac on the source by gamma spectrometry. The detection efficiency is high, allowing analysis of water samples at sufficiently low activity to be suitable in testing for compliance with drinking water quality standards. As (228)Ac grows in quickly, taking less than 2 days to reach equilibrium with the (228)Ra parent, this can also be useful in radiological emergency response situations. The second adaptation incorporates a method for the digestion of BaSO4 sources, allowing separation of thorium and subsequent determination of (228)Th activity. Although ingrowth periods for (228)Th can be lengthy, very low detection limits for (228)Ra can be achieved with this technique. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  18. Uptake and kinetics of /sup 226/Ra, /sup 210/Pb and /sup 210/Po in big sagebrush. [Artemisia tridentata

    SciTech Connect

    Simon, S.L.

    1985-01-01

    Root uptake of /sup 226/Ra, /sup 210/Pb and /sup 210/Po by mature sagebrush was studied using a soil injection method for spiking the soil with minimal root disturbance. The main objective was to measure vegetation concentrations and determine concentration ratios (CR's) due to root uptake as a function of time in mature big sagebrush. Concentration ratios obtained in mature vegetation and in steady-state situations may be valuable in assessing the impact of uranium mining and milling. The vegetation was sampled approximately every 3 months for a 2 year period. Significant levels of activity were detected in the vegetation beginning at the first sampling (81 days after soil injection for /sup 226/Ra, 28 days for /sup 210/Pb and /sup 210/Po). There was an exponential decrease in concentration to an apparent steady-state value. Mean values (geometric) of the data pooled over the second year period indicated that the steady-state CR's for /sup 226/Ra, /sup 210/Pb and /sup 210/Po, as determined in mature sagebrush, were 0.04, 0.009, and 0.08, respectively. A three compartment mathematical model was formulated to help understand mechanisms of plant uptake and to predict, if possible, the concentration of /sup 226/Ra, /sup 210/Pb and /sup 210/Po in vegetation as a function of time after soil spiking. A numerical solution was determined by 'calibrating' the general model solution with constants determined from regressions of concentrations in vegetation, soil leaching and leaf leaching data. Validation of the model is currently not possible because of an absence of similar time-dependent uptake studies. 168 refs., 19 figs., 18 tabs.

  19. Leachable 226Ra in Philippine phosphogypsum and its implication in groundwater contamination in Isabel, Leyte, Philippines.

    PubMed

    Cañete, Socrates Jose P; Palad, Lorna Jean H; Enriquez, Eliza B; Garcia, Teofilo Y; Yulo-Nazarea, Teresa

    2008-07-01

    Phosphogypsum (PG), the major waste material in phosphate fertilizer processing, has been known to contain enhanced levels of naturally-occurring radionuclides especially (226)Ra. The lack of radioactivity data regarding Philippine phosphogypsum and its environmental behavior in the Philippine setting has brought concern on possible contamination of groundwater beneath the phosphogypsum ponds in Isabel, Leyte, Philippines. The radioactivity of Philippine phosphogypsum was determined and the leaching of (226)Ra from phosphogypsum and through local soil was quantified. Level of (226)Ra in groundwater samples in Isabel, Leyte, Philippines was also quantified to address the primary concern. It was found that the (226)Ra activity in Philippine phosphogypsum is distributed in a wide range from 91.5 to 935 Bq/kg. As much as 5% of (226)Ra can be leached from Philippine PG with deionized water. In vitro soil leach experiments suggest that the soil in the phosphate fertilizer plant area would be able to deter the intrusion of (226)Ra into the water table. Compared to reported values of natural groundwater levels of (226)Ra, the concentration of this radionuclide in Isabel, Leyte groundwater suggest that there is no (226)Ra intrusion brought about by the presence of phosphogypsum ponds in the area.

  20. Vertical distribution of (226)Ra and (210)Po in agricultural soils in Buyuk Menderes Basin, Turkey.

    PubMed

    Akyil, S; Gurboga, G; Aslani, M A A; Aytas, S

    2008-09-15

    The vertical distribution of (226)Ra and (210)Po was investigated in the cultivated soils of the Buyuk Menderes Basin in Turkey. Five soil cores down to a depth of about 50 cm were taken from each site and divided into strata of 2-3 cm intervals. The samples were analyzed for their (226)Ra and (210)Po activity concentrations using radioanalytical methods. Down-core concentration profiles of (226)Ra and (210)Po in the soil cores from five sites are obtained. The activity concentrations of soil cores range from 80 to 1170 Bq kg(-1) for (226)Ra and from 10 to 870 Bq kg(-1) for (210)Po with the depth. Analysis of the vertical soil profiles indicate that the activity concentrations of (226)Ra and (210)Po for soil strata at all the sites have not extremely changed with depth.

  1. The Enhancement of 226Ra in a Tidal Estuary due to the Operation of Fertilizer Factories and Redissolution from Sediments: Experimental Results and a Modelling Study

    NASA Astrophysics Data System (ADS)

    Periáñez, R.

    2002-05-01

    The presence of 226Ra in a tidal estuary formerly affected by direct discharges from a phosphate fertilizer complex has been investigated. In general, activity levels are lower than those detected when direct discharges were carried out. However, there is still a clear contamination that can be attributed, presumably, to the disposal of Ra-containing phosphogypsum to the river and to the redissolution of radionuclides from the contaminated sediments. A numerical model of the estuary has been developed to investigate these hypothesis. The hydrodynamics are first calibrated and standard tidal analysis is carried out. The dispersion model computes instantaneous currents from the so obtained tidal constants to speed up simulations. The exchanges of 226Ra between water and the bottom sediment have been described in terms of kinetic transfer coefficients. Model results are, in general, in agreement with observations. The simulation results support the previous idea of sediments acting as a source of 226Ra to the water column.

  2. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    DOE PAGES

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  3. Age-dependent dose assessment of 226Ra from bottled water intake.

    PubMed

    Bronzovic, Maja; Marovic, Gordana

    2005-05-01

    Water may present a source of prolonged exposure to naturally occurring radionuclides. One of the most frequently occurring radionuclides in natural mineral and spring waters is 226Ra and its decay products. The contribution of drinking water to the total exposure is very small, at about 5% of the average effective dose attributable annually to natural background radiation, but that exposure contributes to the risk of adverse health consequences. In this study the mean values of 226Ra concentration determined in natural mineral and spring bottled waters range from 6 to 412 mBq L(-1), which is in accord with Croatian legislation. 226Ra effective doses per year from spring water consumption range up to 86 microSv, while 226Ra effective doses per year from mineral water consumption show much higher values. The highest 226Ra effective doses per year from mineral waters consumption, which are up to seven times higher than the dose recommended by WHO (100 microSv), were found in infants and teens. Based on this study, drinking of certain brands of bottled mineral water is not recommended for these age groups because assessed 226Ra effective doses per year exceed the recommended limits. From other research it is known that testosterone appears in elevated concentration during these life periods and affects bone calcification. Therefore, testosterone could affect the retention of 226Ra into the bone. To make more precise conclusions further research is necessary. Adults and especially elderly people are much less susceptible to the presence of 226Ra. According to the results obtained in this study, 226Ra effective doses per year assessed for these age groups were considerably lower (i.e., 10 microSv).

  4. Determination of (210)Pb and (226)Ra/(228)Ra in continental water using HIDEX 300SL LS-spectrometer with TDCR efficiency tracing and optimized α/β-discrimination.

    PubMed

    Eikenberg, J; Beer, H; Jäggi, M

    2014-11-01

    An analytical method for determination of (210)Pb, (226)Ra and (228)Ra is presented based on adsorption on 3M Empore RadDiscs, and measurement applying liquid scintillation spectrometry (LSC) after elution. The LSC measurement was performed with optimized α/β-discrimination and isotope standardization using the triple to double coincidence ratio (TDCR). The consistency of measurement results between radioactive parent-daughter pairs (210)Pb/(210)Bi, (226)Ra/(222)Rn and (228)Ra/(228)Ac was checked in long-term counting experiments and the influence ofinterference of in-growing daughters from (226)Ra into the β-spectrum of (228)Ra+(228)Ac was studied as well. Recommendations for optimized LSC (228)Ra measurement besides presence of (226)Ra are given.

  5. Assessment of (226)Ra age-dependent dose from water intake.

    PubMed

    Porntepkasemsan, Boonsom; Srisuksawad, Kanitha

    2008-11-01

    The radioactivity in canal and ground waters collected in a 2-year long observation from the vicinity of the Rare Earth Research and Development Center (RRDC), Phathumthani Province, Thailand, was measured in order to determine the concentration of (226)Ra and to estimate the age-dependent effective dose to humans due to consumption. (226)Ra activities in both canal and ground waters were well below the WHO guidance level for drinking water quality of 1 Bq L(-1). The highest (226)Ra effective doses per year were found for infants and teens. However, the observed levels of calculated (226)Ra effective doses for all age groups in both canal and ground waters show satisfactory low values (less than 15 microSv yr(-1)). These values are acceptable in accordance with the WHO recommended reference dose level of 100 microSv yr(-1) from water intake of 2 Lday(-1).

  6. A Study on Sorption of (226)Ra on Different Clay Matrices.

    PubMed

    Alhajji, E; Al-Masri, M S; Khalily, H; Naoum, B E; Khalil, H S; Nashawati, A

    2016-08-01

    The sorption of radium 226 ((226)Ra) on different clay materials (bentonite, illite and a mixture of bentonite-illite) was studied. Clay materials are used in the construction of disposal pits for technically enhanced naturally occurring radioactive materials (TENORM) wastes (i.e., contaminated soil and sludge) generated by the oil and gas industry operations. Experimental conditions (pH, clay materials quantity, and activity concentrations of (226)Ra) were changed in order to determine the optimal state for adsorption of (226)Ra. The results showed that the concentration of adsorbed (226)Ra on clay materials increased with time to reach an equilibrium state after approximately 5 h. More than 95 % of the radium was adsorbed. The mixture of bentonite-illite (1/9) exhibited the greatest adsorption of radium under all experimental conditions.

  7. Distribution and retention in bone of /sup 226/Ra and comparison with the ICRP 20 model

    SciTech Connect

    Holtzman, R.B.; Rundo, J.; Sha, J.Y.; Spaletto, M.I.

    1981-01-01

    Analyses are presented of the ratios of /sup 226/Ra to calcium in over 650 samples of compact and cancellous bone from 66 female and 26 male subjects who had died from less than one to 60 years after first exposure to radium. The /sup 226/Ra/Ca ratios were normalized to the terminal /sup 226/Ra skeletal content. The /sup 226/Ra/Ca ratios for vertebrae were essentialy identical to those for other cancellous bone for a given subject. Comparisons of the data with predictions of the ICRP model of alkaline earth metabolism show that for female cancellous bone the normalized /sup 226/Ra/Ca ratios tended to be greater than predicted, while those for female cortical bone (femoral and tibial shaft) tended to be less. The data for males were fitted better by the model. A modification of the model to reduce the amount of radium deposited in soft tissue fitted the data better in some respects. A straight line linear least squares fit to the data appeared to fit as well as, or better than, the models. A radiation effect was suggested in that the normalized /sup 226/Ra/Ca ratio for vertebrae relative to the ratio expected increased with skeletal absorbed dose for vertebra. However, no such effect was apparent for compact bone or for the cancellous bone as a whole.

  8. Analytical study of (226)Ra activity concentration in market consuming foodstuffs of Ramsar, Iran.

    PubMed

    Gooniband Shooshtari, M; Deevband, M R; Kardan, M R; Fathabadi, N; Salehi, A A; Naddafi, K; Yunesian, M; Nabizadeh Nodehi, R; Karimi, M; Hosseini, S S

    2017-01-01

    Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine (226)Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. Approximately 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. All samples, after washing, drying and pretreatment, were analyzed for (226)Ra radionuclide determination by α-spectrometry. The mean radioactivity concentration of (226)Ra ranged between 7 ± 1 mBq Kg(-1) wet weight in meat, and 318 ± 118 mBq Kg(-1) for tea dry leaves. The (226)Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg(-1). To compare the results with United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) reference values, the (226)Ra activity concentrations concluded from the results appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant (226)Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar. Of the total daily dietary (226)Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast

  9. Transfer coefficient of 226Ra from vegetation to meadow voles, Microtus pennsylvanicus, on U mill tailings

    SciTech Connect

    Cloutier, N.R.; Clulow, F.V.; Lim, T.P.; Dave, N.K.

    1986-06-01

    The 226Ra level in vegetation growing on U mine tailings in Elliot Lake, Ontario, Canada, was 211 + 22 mBq g-1 (dry weight) compared to less than 7 mBq g-1 (dry weight) in material from a control site. Skeletons of meadow voles (Microtus pennsylvanicus) established on the tailings had concentrations of 226Ra of 6083 +/- 673 mBq per animal in winter; 7163 +/- 1077 mBq per animal in spring; 1506 +/- 625 mBq per animal in summer; and 703 +/- 59 mBq per animal in fall, compared to less than 7 mBq per animal in controls. The /sup 226/Ra transfer coefficient from vegetation to voles (defined as total millibecquerels of /sup 226/Ra in adult vole per total millibecquerels of 226Ra consumed by the vole in its lifetime) was calculated as 4.6 +/- 2.9 X 10(-2) in summer and 2.8 +/- 0.6 X 10(-2) in fall.

  10. 210Pb-226Ra disequilibria in young gas-laden magmas

    PubMed Central

    Reagan, Mark; Turner, Simon; Handley, Heather; Turner, Michael; Beier, Christoph; Caulfield, John; Peate, David

    2017-01-01

    We present new 238U-230Th-226Ra-210Pb and supporting data for young lavas from southwest Pacific island arcs, Eyjafjallajökull, Iceland, and Terceira, Azores. The arc lavas have significant 238U and 226Ra excesses, whereas those from the ocean islands have moderate 230Th and 226Ra excesses, reflecting mantle melting in the presence of a water-rich fluid in the former and mantle melting by decompression in the latter. Differentiation to erupted compositions in both settings appears to have taken no longer than a few millennia. Variations in the (210Pb/226Ra)0 values in all settings largely result from degassing processes rather than mineral-melt partitioning. Like most other ocean island basalts, the Terceira basalt has a 210Pb deficit, which we attribute to ~8.5 years of steady 222Rn loss to a CO2-rich volatile phase while it traversed the crust. Lavas erupted from water-laden magma systems, including those investigated here, commonly have near equilibrium (210Pb/226Ra)0 values. Maintaining these equilibrium values requires minimal persistent loss or accumulation of 222Rn in a gas phase. We infer that degassing during decompression of water-saturated magmas either causes these magmas to crystallize and stall in reservoirs where they reside under conditions of near stasis, or to quickly rise towards the surface and erupt. PMID:28338093

  11. 210Pb-226Ra disequilibria in young gas-laden magmas

    NASA Astrophysics Data System (ADS)

    Reagan, Mark; Turner, Simon; Handley, Heather; Turner, Michael; Beier, Christoph; Caulfield, John; Peate, David

    2017-03-01

    We present new 238U-230Th-226Ra-210Pb and supporting data for young lavas from southwest Pacific island arcs, Eyjafjallajökull, Iceland, and Terceira, Azores. The arc lavas have significant 238U and 226Ra excesses, whereas those from the ocean islands have moderate 230Th and 226Ra excesses, reflecting mantle melting in the presence of a water-rich fluid in the former and mantle melting by decompression in the latter. Differentiation to erupted compositions in both settings appears to have taken no longer than a few millennia. Variations in the (210Pb/226Ra)0 values in all settings largely result from degassing processes rather than mineral-melt partitioning. Like most other ocean island basalts, the Terceira basalt has a 210Pb deficit, which we attribute to ~8.5 years of steady 222Rn loss to a CO2-rich volatile phase while it traversed the crust. Lavas erupted from water-laden magma systems, including those investigated here, commonly have near equilibrium (210Pb/226Ra)0 values. Maintaining these equilibrium values requires minimal persistent loss or accumulation of 222Rn in a gas phase. We infer that degassing during decompression of water-saturated magmas either causes these magmas to crystallize and stall in reservoirs where they reside under conditions of near stasis, or to quickly rise towards the surface and erupt.

  12. (210)Pb-(226)Ra disequilibria in young gas-laden magmas.

    PubMed

    Reagan, Mark; Turner, Simon; Handley, Heather; Turner, Michael; Beier, Christoph; Caulfield, John; Peate, David

    2017-03-24

    We present new (238)U-(230)Th-(226)Ra-(210)Pb and supporting data for young lavas from southwest Pacific island arcs, Eyjafjallajökull, Iceland, and Terceira, Azores. The arc lavas have significant (238)U and (226)Ra excesses, whereas those from the ocean islands have moderate (230)Th and (226)Ra excesses, reflecting mantle melting in the presence of a water-rich fluid in the former and mantle melting by decompression in the latter. Differentiation to erupted compositions in both settings appears to have taken no longer than a few millennia. Variations in the ((210)Pb/(226)Ra)0 values in all settings largely result from degassing processes rather than mineral-melt partitioning. Like most other ocean island basalts, the Terceira basalt has a (210)Pb deficit, which we attribute to ~8.5 years of steady (222)Rn loss to a CO2-rich volatile phase while it traversed the crust. Lavas erupted from water-laden magma systems, including those investigated here, commonly have near equilibrium ((210)Pb/(226)Ra)0 values. Maintaining these equilibrium values requires minimal persistent loss or accumulation of (222)Rn in a gas phase. We infer that degassing during decompression of water-saturated magmas either causes these magmas to crystallize and stall in reservoirs where they reside under conditions of near stasis, or to quickly rise towards the surface and erupt.

  13. Comparative Analysis Of 226Ra Soil-To-Plant Transfer In Cabbage Grown In Various Regions

    NASA Astrophysics Data System (ADS)

    Madruga, M. J.; Carvalho, F. P.; Silva, L.; Gouveia, J.

    2008-08-01

    The transfer of 226Ra from soil to cabbage was compared amongst regions, namely the surroundings of Urgeiriça uranium milling tailings (GE), regions with past uranium mining activities (GN1), and regions with no uranium mining activities and no uranium deposits (GN2). Results show a slight increase of the concentration ratio values at low radium concentration in soils. Statistical analysis of the mean 226Ra activity concentrations in soil and cabbage for the three regions was carried out. The comparison of 226Ra activity concentrations in soils indicated no difference (p>0.05), between GE and GN2 and significant differences (p<0.05) between GE and GN1 and between GN1 and GN2. Similar statistical results were obtained for 226Ra activity concentrations in cabbage from the same regions. It was concluded that radium Concentration Ratio (CR) for cabbage grown in the region of the main uranium milling site (GE) is of the same order of magnitude of CR in cabagge grown in background regions (GN2). However, 226Ra CR was higher in cabagge from the region with past uranium mining activities (GN1).

  14. Transfer coefficient of 226Ra from vegetation to meadow voles, Microtus pennsylvanicus, on U mill tailings.

    PubMed

    Cloutier, N R; Clulow, F V; Lim, T P; Davé, N K

    1986-06-01

    The 226Ra level in vegetation growing on U mine tailings in Elliot Lake, Ontario, Canada, was 211 + 22 mBq g-1 (dry weight) compared to less than 7 mBq g-1 (dry weight) in material from a control site. Skeletons of meadow voles (Microtus pennsylvanicus) established on the tailings had concentrations of 226Ra of 6,083 +/- 673 mBq per animal in winter; 7,163 +/- 1,077 mBq per animal in spring; 1,506 +/- 625 mBq per animal in summer; and 703 +/- 59 mBq per animal in fall, compared to less than 7 mBq per animal in controls. The 226Ra transfer coefficient from vegetation to voles (defined as total millibecquerels of 226Ra in adult vole per total millibecquerels of 226Ra consumed by the vole in its lifetime) was calculated as 4.6 +/- 2.9 X 10(-2) in summer and 2.8 +/- 0.6 X 10(-2) in fall.

  15. Distribution and flux of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary

    SciTech Connect

    Key, R.M.; Sarmiento, J.L.; Stallard, R.F.; Moore, W.S.

    1985-07-20

    Measurements of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary show that desorption from riverborne suspended particulate matter in the estuary increases the riverine flux of both isotopes to the ocean by a factor of approximately 5 over the flux attributable to radium dissolved in the river water alone. The total Amazon flux supplies approximately 0.20% of the /sup 226/Ra and approximately 2.6% of the /sup 228/Ra standing crops in the near-surface Atlantic (0-200 m). Diffusive flux from estuarine and shelf sediments and desorption from resuspended sediments in the region of the estuary approximately double the estuarine /sup 226/Ra concentration and quadruple the estuarine /sup 228/Ra concentration above that caused by the dissolved and desorbed river components alone.

  16. A rapid and inexpensive method for 226Ra and 228Ra measurements of high TDS groundwaters.

    PubMed

    El-Shrakawy, A; Ebaid, Y Y; Burnett, W C; Aldaihan, Soaad K

    2013-07-01

    A series of laboratory-scale studies was conducted by preconcentrating (226)Ra from spiked water test samples using Purolite ion-exchange resin to evaluate the adsorption efficiency of the resin under varying conditions. After removing the resin from the columns, it was sealed in gas-tight containers and measured via gamma spectrometry. The Purolite resin showed high radium uptake and retention from natural waters in the presence of high iron and total dissolved solids (TDS). This procedure allowed us to process a large number of high TDS samples at a typical rate of 15 samples/day using three germanium detectors. Quality assurance and method validation have been achieved by analyzing selected groundwater samples, with different (226)Ra activities and high TDS values, and comparing the results to those using alpha spectrometry with a (133)Ba yield tracer. There was very good agreement between the obtained (226)Ra activities by both methods.

  17. Concentrations of (226)Ra, (232)Th and (4)(0)K in industrial kaolinized granite.

    PubMed

    Todorović, Nataša; Hansman, Jan; Mrđa, Dušan; Nikolov, Jovana; Kardos, Richárd; Krmar, Miodrag

    2017-03-01

    Activity concentrations of (226)Ra, (232)Th and (4)(0)K in 120 kaolinized granite samples imported in Serbia from the Motajica mine, Bosnia and Herzegovina, were measured. The (226)Ra concentration ranged from 61 to 319 Bq kg(-1), the (232)Th from 44 to 272 Bq kg(-1), and the (4)(0)K from 590 to 1470 Bq kg(-1). The frequency distribution of (4)(0)K concentrations was near-Gaussian, where those of (226)Ra and (232)Th were right-skewed. In 6 samples, the gamma index, I, was higher than 2, which exceeds the exemption dose criterion (0.3 mSv y(-1)). The absorbed dose rate and annual effective doses for workers in the ceramic industries in Serbia who worked with kaolinized granite were below levels of concern.

  18. Release of 226Ra from uranium mill tailings by microbial Fe(III) reduction

    USGS Publications Warehouse

    Landa, E.R.; Phillips, E.J.P.; Lovley, D.R.

    1991-01-01

    Uranium mill tailings were anaerobically incubated in the presence of H2 with Alteromonas putrefaciens, a bacterium known to couple the oxidation of H2 and organic compounds to the reduction of Fe(III) oxides. There was a direct correlation between the extent of Fe(III) reduction and the accumulation of dissolved 226Ra. In sterile tailings in which Fe(III) was not reduced, there was negligible leaching of 226Ra. The behavior of Ba was similar to that of Ra in inoculated and sterile systems. These results demonstrate that under anaerobic conditions, microbial reduction of Fe(III) may result in the release of dissolved 226Ra from uranium mill tailings. ?? 1991.

  19. Occurrence of 222Rn, 226Ra, 228Ra and U in groundwater in Fujian Province, China.

    PubMed

    Zhuo, W; Iida, T; Yang, X

    2001-01-01

    222Rn, 226Ra, 228Ra and U were determined in a total of 552 groundwater samples collected throughout Fujian Province of China. The geometric mean concentrations of 222Rn, 226Ra, 228Ra and total U in the groundwater were 147.8 kBq m-3, 12.7 Bq m-3, 30.2 Bq m-3 and 0.54 microgram kg-1, respectively. High groundwater 222Rn was explained by the predominantly granitic rock aquifers in Fujian. A lifetime risk of 1.7 x 10(-3) was estimated for the ingestion of groundwater 222Rn. High ratios of 228Ra to 226Ra contents (geometric mean of 2.4) and their disproportion suggest that 228Ra should also be measured in the assessment of population doses from drinking water in the regions of high rock or soil 232Th. No significant correlation between the 222Rn concentrations in groundwater and air was found.

  20. Development of low level 226Ra analysis for live fish using gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Chandani, Z.; Prestwich, W. V.; Byun, S. H.

    2017-06-01

    A low level 226Ra analysis method for live fish was developed using a 4π NaI(Tl) gamma-ray spectrometer. In order to find out the best algorithm for accomplishing the lowest detection limit, the gamma-ray spectrum from a 226Ra point was collected and nine different methods were attempted for spectral analysis. The lowest detection limit of 0.99 Bq for an hour counting occurred when the spectrum was integrated in the energy region of 50-2520 keV. To extend 226Ra analysis to live fish, a Monte Carlo simulation model with a cylindrical fish in a water container was built using the MCNP code. From simulation results, the spatial distribution of the efficiency and the efficiency correction factor for the live fish model were determined. The MCNP model will be able to be conveniently modified when a different fish or container geometry is employed as fish grow up in real experiments.

  1. Systematic study of heavy cluster emission from 210-226Ra isotopes

    NASA Astrophysics Data System (ADS)

    Santhosh, K. P.; Sahadevan, Sabina; Priyanka, B.; Unnikrishnan, M. S.

    2012-05-01

    The half lives for various clusters lying in the cold reaction valleys of 210-226Ra isotopes are computed using our Coulomb and proximity potential model (CPPM). The computed half lives of 4He and 14C clusters from 210-226Ra isotopes are in good agreement with experimental data. Half lives are also computed using the universal formula for cluster decay (UNIV) of Poenaru et al., and are found to be in agreement with CPPM values. Our study reveals the role of doubly magic 208Pb daughter in cluster decay process. Geiger-Nuttall plots for all clusters up to 62Fe are studied and are found to be linear with different slopes and intercepts. 12,14C emission from 220Ra; 14C emission from 222,224Ra; 14C and 20O emission from 226Ra are found to be most favourable for measurement and this observation will serve as a guide to the future experiments.

  2. Water hardness determines (226)Ra uptake in the tropical freshwater mussel.

    PubMed

    Doering, Che; Bollhöfer, Andreas

    2017-03-22

    Chemical data for freshwater mussels (Velesunio spp.) and water from 15 sampling sites in the Alligator Rivers Region and Rum Jungle uranium provinces in tropical Northern Australia were analysed to develop a predictive model of radium-226 ((226)Ra) bioaccumulation for variable water calcium (Ca) and magnesium (Mg) concentrations. Application of the model as a (226)Ra screening approach for freshwater mussels in tropical waterbodies potentially impacted by operational or remediated uranium mine sites is discussed in relation to Mudginberri Billabong, located approximately 12 km downstream of Ranger uranium mine in the Alligator Rivers Region.

  3. Bioaccumulation of 226Ra by plants growing in fresh water ecosystem around the uranium industry at Jaduguda, India.

    PubMed

    Jha, V N; Tripathi, R M; Sethy, N K; Sahoo, S K; Shukla, A K; Puranik, V D

    2010-09-01

    A field study has been conducted to evaluate the (226)Ra bioaccumulation among aquatic plants growing in the stream/river adjoining the uranium mining and ore-processing complex at Jaduguda, India. Two types of plant group have been investigated namely free floating algal species submerged into water and plants rooted in stream & riverbed. The highest (226)Ra activity concentration (9850 Bq kg(-1)) was found in filamentous algae growing in the residual water of tailings pond. The concentration ratios of (226)Ra in filamentous algae (activity concentration of (226)Ra in plant Bq kg(-1) fresh weight/activity concentration of (226)Ra in water Bq l(-1)) widely varied i.e. from 1.1 x 10(3) to 8.6 x 10(4). Other aquatic plants were also showing wide variability in the (226)Ra activity concentration. The ln-transformed filamentous algae (226)Ra activity concentration was significantly correlated with that of ln-transformed water concentration (r = 0.89, p < 0.001). There was no correlation between the activity concentrations of (226)Ra in stream/riverbed rooted plants and the substrate. For this group, correlation between (226)Ra activity concentration and Mn, Fe, Cu concentration in plants were statistically significant.

  4. Measuring the radium quartet (228Ra, 226Ra, 224Ra, 223Ra) in seawater samples using gamma spectrometry.

    PubMed

    van Beek, P; Souhaut, M; Reyss, J-L

    2010-07-01

    Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228Ra and 226Ra are usually measured using gamma spectrometry, short-lived Ra isotopes (224Ra and 223Ra) are usually measured using a Radium Delayed Coincidence Counter (RaDeCC). Here we show that the four radium isotopes can be analyzed using gamma spectrometry. We report 226Ra, 228Ra, 224Ra, 223Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccarès lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The 223Ra and 224Ra activities determined in these samples using gamma spectrometry were compared to the activities determined using RaDeCC. Activities determined using the two techniques are in good agreement. Uncertainties associated with the 224Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low 223Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes. 2009 Elsevier Ltd. All rights reserved.

  5. Simultaneous measurement of (226)Ra and (228)Ra in natural water by liquid scintillation counting.

    PubMed

    Lasheen, Yasser F; Seliman, Ayman F; Abdel-Rassoul, A A

    2007-01-01

    Several types of bottled drinking water originating from three different areas in Egypt are studied through measurement of radium activity, assessment of related annual dose for adults and finally to define the role of water quality on radium levels. The mean levels of (226)Ra activity range from 0.44 to 0.92 Bq/L and the mean levels of (228)Ra from 0.30 to 0.78 Bq/L, with related (226)Ra/(228)Ra ratios ranging from 2.61 to 0.56. Water types originating from the Eastern Nile Delta area are characterized by low (226)Ra levels and relatively high (228)Ra activity, presumably due to the muddy agricultural nature of this area, which is subject to water from several surface resources for irrigation. In general, the mean activity levels for both (226)Ra and (228)Ra are within those in drinking water in several other countries and the annual ingested dose is comparable with the typical range reported by UNSCEAR. Also, the effect of TDS, pH, calcium, bicarbonate, sulphate and chloride ion concentrations on radium levels is studied and discussed.

  6. Determination of (226)Ra in produced water by liquid scintillation counting.

    PubMed

    Godoy, José Marcus; Vianna, Lucas M; Godoy, Maria Luiza D P; Almeida, Ana Cristina

    2016-08-01

    It is proposed a method for the determination of (226)Ra in offshore platform liquid effluent samples (produced water). The method is based on a two-phase liquid scintillation counting system and allows for the direct and simple determination of (226)Ra content. Samples with high barium content may also have high (226)Ra concentration. Therefore, the sample volume is based on the barium concentration and ranges from 10 mL to 100 mL. Our new method was tested using multiple real samples and was compared with the BaSO4 precipitation method. The results based on the LSC were 30% higher than the precipitation method, which is attributed to the self-absorption of alpha particles in the BaSO4 precipitate. The determination of both (226)Ra and (228)Ra in the liquid effluent of offshore oil platforms is mandatory in Brazil. Thus, a second method of accurately assessing (228)Ra content remains necessary. Copyright © 2016. Published by Elsevier Ltd.

  7. Ingestion of 226Ra from activated paints on military equipment: transfer factors and doses.

    PubMed

    Schirmer, A

    2010-10-01

    The use of 226Ra-activated markings was specific for military equipment some decades ago and the extent of possible internal exposure of former military personnel due to ingestion of 226Ra is an issue of discussion. Whole- or partial-body counts are not sensitive enough to trace an overexposure due to a possible 226Ra uptake four decades ago. Thus retrospective workplace assessments are needed. These are done by wiping tests with linen and skin pads on 226Ra markings on decommissioned military equipment. The contamination investigations are performed in wipe-activity measuring cycles with exponentially increasing numbers of wipes. The activity wiped off does not increase with the number of wipes but levels off instead. Wipes with linen pads are more effective than wipes with skin. The skin-skin activity transfer is investigated by respective wipes too. The maximum committed dose in a typical scenario is calculated under worst case assumptions. For the typical work of 1 y an effective dose of about 70 μSv, and for the bone surface a dose of about 3 mSv, is obtained.

  8. 226Ra activity in the mullet species Liza aurata and South Adriatic Sea marine.

    PubMed

    Antovic, N M; Antovic, I; Svrkota, N

    2010-08-01

    (226)Ra activity in the South Adriatic Sea-water, surface sediment, mud with detritus, seagrass (Posidonia oceanica) samples and the mullet (Mugilidae) species Liza aurata, as well as soil and sand from the Montenegrin Coast-was measured using the six-crystal gamma-coincidence spectrometer PRIPYAT-2M. The results are used for calculation of the absorbed (and annual effective) dose rates in air due to the (226)Ra gamma radiation. The absorbed dose rates ranged from 5.94 to 97.16 nGy h(-1) (soil) and from 0.65 to 7.65 nGy h(-1) (sand). In seawater (226)Ra activity is found to be from 0.08 to 0.15 Bq l(-1), while in whole L. aurata individuals from 0.58 to 1.97 Bq kg(-1). Annual intake of (226)Ra by human consumers of this fish species has been estimated to provide an effective dose of 0.006 mSv y(-1).

  9. Estuarine geochemistry of /sup 224/Ra, /sup 226/Ra, and /sup 222/Rn

    SciTech Connect

    Elsinger, R.J.

    1982-01-01

    Desorption from river borne sediments is the most likely source of the excess /sup 226/Ra. Laboratory mixing experiments on Pee Dee River sediments show an increase in /sup 226/Ra desorption with increasing salinities with maximum desorption occurring at or above 20/sup 0//oo salinity. Desorption and diffusion are the sources for /sup 226/Ra in the estuarine systems. In Winyah Bay the /sup 228/Ra//sup 226/Ra activity ratio does not change significantly with salinity, averaging around 1.4, indicating desorption as the major source of /sup 228/Ra. In the Yangtze River the /sup 228/Ra//sup 226/Ra activity ratio is constant (approx.1.90) until increasing linearly above 16/sup 0//oo. A diffusive flux from regeneration by /sup 232/Th decay in shelf sediments is the source of the increase. In Delaware Bay /sup 228/Ra increases faster than /sup 226/Ra in the less than or equal to22/sup 0//oo water, indicating a source in addition to desorption. The increase can be balanced by a 0.33 dpm/cm/sup 2/-year flux over the upper part of the Bay where fine grained sediments predominate. /sup 224/Ra behavior is controlled by its 3.64 day half-life. In Winyah Bay a flux of around 0.4 dpm/cm/sup 2/-day is necessary to support the standing crop of non-desorbed /sup 224/Ra in the water column. In Delaware Bay the nearly constant /sup 224/Ra in concentration over the 2.5/sup 0//oo to 12/sup 0//oo salinity range are maintained by regeneration from /sup 228/Th in the turbidity maximum zones and diffusion from bottom sediments. Water leaving on ebb tide from a salt marsh on Delaware Bay had increases in all three radium isotopes (/sup 224/Ra > /sup 228/Ra > /sup 226/Ra) compared to water coming in on the flood tide. Excess /sup 222/Rn concentrations in a fresh water section of the Pee Dee River show a decreasing downstream gradient. Using these gradients to determine evasion rates, stagnant film thicknesses range from 21..mu.. to 62..mu...

  10. Occurrence of 224Ra, 226Ra, 228Ra, gross alpha, and uranium in California groundwater.

    PubMed

    Ruberu, Shiyamalie R; Liu, Yun-Gang; Perera, S Kusum

    2005-12-01

    One hundred and twelve groundwater wells sampled from all the major aquifers in California were analyzed for 224Ra, 226Ra, 228Ra, gross alpha, and uranium. The results showed that radium is found in relatively low concentration, 1.56 x 10(-2)-1.23 Bq L(-1) (0.42-33 pCi L(-1)) for 224Ra, 2.2 x 10(-3)-0.81 Bq L(-1) (0.06-22 pCi L(-1)) for 226Ra, and 8.5 x 10(-3)-1.31 Bq L(-1) (0.23-35 pCi L(-1)) for 228Ra in California groundwater. Uranium was found at the highest concentration on both mass and activity basis and was correlated with the gross alpha measurement. Short-lived radioisotopes showed no significant contribution to gross alpha measurements. There was a strong correlation between 224Ra and 228Ra activities, suggesting the latter to be an indicator for the occurrence of the former. Comparison of 226Ra to 238U, 224Ra to 226Ra, and 226Ra to 228Ra showed scattered data indicating no correlation between each of these isotope pairs. Approximately 4% of the wells were found to exceed the U.S. Environmental Protection Agency (EPA) established maximum contaminant level for total radium of 0.185 Bq L(-1) (5 pCi L(-1)). Analysis of 228Ra by gamma-ray spectroscopy was in good agreement with the U.S. EPA-approved procedure.

  11. Metrological Determination of Natural Radioactive Isotopes {sup 226}Ra, {sup 228}Ra and {sup 210}Pb by Means of Ge Detector

    SciTech Connect

    Almeida, Maria Candida M. de; Delgado, Jose U.; Poledna, Roberto; Oliveira, Estela Maria de; Silva, Ronaldo L. da

    2008-08-07

    A metrological method to determine the activity per mass unity (activity concentration) of {sup 226}Ra and {sup 210}Pb ({sup 238}U decay series) and {sup 228}Ra ({sup 232}Th series) by gamma-ray spectrometers based on hyper-pure coaxial germanium detector was developed. In the soil the {sup 22}Ra (half-life = 1600 years) exhibits the same level of radioactivity as {sup 238}U (half-life 4.5x10{sup 9} years) because of a natural phenomenon called secular equilibrium. {sup 226}Ra decays into {sup 222}Rn (half-life = 3.8 days), a radioactive inert gas. After several days, the {sup 222}Rn naturally decays to {sup 218}Po (half-life = 3 minutes), where finally {sup 210}Pb (half-life = 22 years) is produced. The metrological capability of high-resolution gamma-ray spectrometry for naturally occurring radionuclides at environmental levels is showed, with emphasis on the use of 2 mL standard sources volume in a glass ampoule. Source preparation and calibration procedures are described. Radionuclide standards in an activity range of 10 to 250 Bq/g were produced which can be applied in a variety of environmental sample analysis (water, plant material, sediment, etc.). Uncertainties for {sup 226}Ra and {sup 210}Pb around 3% (k = 1) were obtained.

  12. Sorption of 226Ra from waste effluents using Syrian bentonite.

    PubMed

    Al Attar, L; Al Masri, M S; Budeir, Y; Al Chayah, O

    2010-12-14

    In view of environmental concern, sorption of radium on natural bentonite mineral (Aleppo, Syria) was investigated using a batch-type method. Data were expressed in terms of distribution coefficients. An attempt to increase the selectivity of bentonite for radium was made by preparing M-derivatives. Loss of mineral crystallinity in acidic media and the formation of a new phase, such as BaCO3, in Ba-derivative were evidenced by XRD characterizations. Of the cationic forms, Na-bentonite showed the highest affinity. Mechanisms of radium uptake were studied using M-derivatives and simulated radium solutions. The obtained results indicated that surface sorption/surface ion exchange were the predominant processes. The distinct sorption behaviour observed with the Ba-form was, possibly, a reflection of radium coprecipitation with barium carbonate. The competing order of macro components, likely present in waste streams, was investigated by studying different concentrations of the corresponding salt media. Sodium was found to be the weakest inhibitor. The performance of natural bentonite and the most selective forms, i.e. Ba- and Na-derivatives, to sorb radium from actual oil co-produced waters, collected form Der Ezzor Petroleum Company (DEZPC), was studied. This showed the influential effect ofpH compared with other parameters.

  13. The development of a 222Rn standard solution dispenser at NPL.

    PubMed

    Dean, J C J; Kolkowski, P

    2004-01-01

    The design, operation and performance of a unit for dispensing standardised aqueous solutions of 222Rn is described. The unit consists of a sealed polyethylene capsule (containing a known weight of a 226Ra standard solution) immersed in water inside a cylindrical stainless-steel accumulation chamber. The chamber is fitted with valves at each end and has a central bellows so that the chamber can be compressed to dispense solution. The degree of compression, and thus the weight of solution dispensed, is controlled by a microprocessor-controlled motor-drive mechanism. The solution is dispensed via a needle positioned beneath the lower valve.

  14. Biological availability of (238)U, (234)U and (226)Ra for wild berries and meadow grasses in natural ecosystems of Belarus.

    PubMed

    Sokolik, G A; Ovsiannikova, S V; Voinikava, K V; Ivanova, T G; Papenia, M V

    2014-01-01

    This work is devoted to investigation of behavior of (234)U, (238)U and (226)Ra by determining the soil to plant transfer under different natural conditions such as forest or swamped areas and meadow lands with different soil types. The paper summarizes the data on investigation of uranium and radium uptake by wild berries and natural meadow grasses in the typical conditions of Belarus. Parameters characterizing the biological availability of (234)U, (238)U and (226)Ra for bilberry (Vaccinium myrtillus), lingonberry (Vaccinium viti-idaea), blueberry (Vaccinium iliginosum) and cranberry (Vaccinium oxycoccus palustris) as well as for widely occurring mixed meadow vegetation, which belongs to the sedge-grass or grass-sedge associations and forbs, have been established. In the sites under investigation, the deposition levels of (238+239+240)Pu were less than 0.37 kBq m(-2) and (137)Cs deposition ranged between less than 0.37 and 37 kBq m(-2). It was found that activity concentrations of radionuclides in berries varied in the ranges of 0.037-0.11 for (234)U, 0.036-0.10 for (238)U and 0.11-0.43 Bq kg(-1) for (226)Ra, but in the mixed meadow grasses they were 0.32-4.4, 0.24-3.9 and 0.14-6.9 Bq kg(-1) accordingly. The (234)U/(238)U activity ratios were 1.02 ± 0.01 for wild berries, 1.20 ± 0.09 for underground meadow grasses and 1.02 ± 0.02 for proper soils. The concentration ratios (CRs, dry weight basis) of (234)U and (238)U for mixed meadow grasses were 0.036-0.42 and 0.041-0.46 respectively. The correspondent geometric means (GM) were 0.13 and 0.15 with geometric standard deviations (GSD) of 2.4. The CRs of (226)Ra for meadow grasses were 0.031-1.0 with GM 0.20 and GSD 2.6. The CRs of (234)U, (238)U and (226)Ra for wild berries ranged within 0.0018-0.008 (GM is 0.0034, GSD is 1.8), 0.0018-0.008 (GM is 0.0035, GSD is 1.8) and 0.005-0.033 (GM is 0.016, GSD is 2.1) accordingly. The highest CR values of uranium for mixed meadow grasses were found in the

  15. Study of contents of 226Ra, 232Th and 40K in fertilisers.

    PubMed

    Tahir, S N A; Alaamer, A S; Omer, R M

    2009-02-01

    In this study concentrations of naturally occurring radionuclides (226)Ra, (232)Th and (40)K were measured in the fertiliser samples in Pakistan using a high-resolution and high-purity germanium detector. Samples were collected from main fertiliser depots located in 10 big cities in the Punjab province. Gamma spectrometric analysis revealed that concentrations of (226)Ra, (232)Th and (40)K existed in the ranges from 232 to 511 Bq kg(-1), 21 to 58 Bq kg(-1) and 556 to 1302 Bq kg(-1) with average values of 386 +/- 92, 38 +/- 14 and 885 +/- 220 Bq kg(-1), respectively. Average values of the three natural radionuclides measured in this study were within the range of reported values from some of the other countries of the world. Correlations drawn between measured concentrations were not significant.

  16. [sup 226]Ra-[sup 230]Th disequilibrium in axial and off-axis mid-ocean ridge basalts

    SciTech Connect

    Volpe, A.M.; Goldstein, S.J. Los Alamos National Lab., NM )

    1993-03-01

    The authors describe [sup 226]Ra-[sup 230]Th disequilibrium in mid-ocean ridge basalt (MORB) glasses from the Juan de Fuca, Gorda, and East Pacific ridges. These first mass spectrometric measurements of [sup 226]Ra in MORB glasses at sub-picogram abundance levels confirm the large excesses over [sup 230]Th determined by radon-emanation techniques and alpha spectrometry. All off-axis MORB glasses have [sup 226]Ra-[sup 230]Th and [sup 234]U-[sup 238]U in secular equilibrium. This suggests that magmatic processes, not secondary post-eruption alteration, generate [sup 238]U-series disequilibrium in these MORB. Least evolved, N-MORB from axial valleys have ([sup 226]Ra/[sup 230]Th) between 2.2-2.3. Differentiated and enriched E-type MORB have consistently low ([sup 226]Ra/[sup 230]Th) ratios compared with N-MORB from the same ridge sections. Ra-Th fractionation may be less pronounced, or magma residence-transit periods may be long for differentiated MORB. Also, E-MORB may be generated by different melt extraction volumes and rates. Estimated [sup 226]Ra-[sup 230]Th ages for N-MORB agree with location on and off ridge segments, and with Th-U model ages. These preliminary results show that [sup 226]Ra-[sup 230]Th disequilibrium could be used to quantify volcanic episodicity at ocean ridges. 39 refs., 6 figs., 4 tabs.

  17. Origin and transport of (238)U and (226)Ra in riverine, estuarine and marine sediments of the Krka River, Croatia.

    PubMed

    Cukrov, Neven; Mlakar, Marina; Cuculić, Vlado; Barisić, Delko

    2009-06-01

    Spatial distribution of (238)U and (226)Ra activities in sediment columns along the Krka River and estuary, were studied using gamma spectrometry. Markedly different (238)U and (226)Ra activities between riverine, estuarine and marine sediments were observed. Distribution of these radionuclides, as well as their anthropogenic and natural origin, was evaluated by activity measurements, taking into account sedimentation rates estimated by (137)Cs distribution in sediment columns. Naturally present (238)U and (226)Ra activities were highest in riverine and lowest in marine sediments. (238)U and (226)Ra activities in historic riverine sediments revealed anthropogenic influence from town of Knin, which diminished for 15-20% in 1990s due to warfare that caused stop of industrial, agricultural and transport activities. Drainage of the flysch material naturally elevates (238)U and (226)Ra activities in the vicinity of its inflow in the upper part of estuary. (238)U and (226)Ra from the phosphate ore discharge in the port of Sibenik did not spread further in estuary, which was also confirmed by (238)U and (226)Ra activities detected in Mytilus sp. mussels' tissue.

  18. 18O and 226Ra in the Minjiang River estuary, China and their hydrological implications

    NASA Astrophysics Data System (ADS)

    Liu, Huatai; Guo, Zhanrong; Gao, Aiguo; Yuan, Xiaojie; Zhang, Bin

    2016-05-01

    In this work, the 2H, 18O and 226Ra values in groundwater and surface water in the Minjiang River estuary were investigated in the dry and wet seasons. The δ18O values in the dry season were always higher than those in the wet season in both groundwater and surface water because of the presence of evaporation in the water cycle process. During the dry season, the δ18O values in groundwater on the southern bank of the Minjiang River are much higher than those on the northern bank because evaporation is more intense in the farmland of the southern bank than in the urbanized northern bank. The δ18O values in the estuarine water exhibit a good positive correlation with salinity, with a coefficient of 0.96 (p = 0.05) in both seasons. The 226Ra activities in the estuarine water increase with increasing salinity because of desorption from riverine suspended particles. The 226Ra activity reaches a peak value at a salinity of 20.5. Based on a three-endmember model, the average proportions of the estuarine water are calculated to be 0.02 for groundwater, 0.39 for river water and 0.59 for seawater. From this mixing ratio, the groundwater discharge into the estuary is estimated to be 9.31 × 106 m3 d-1 in the wet season.

  19. Effective dose to the public from 226Ra in drinking water supplies of Iran.

    PubMed

    Sohrabi, M; Beitollahi, M M; Hafezi, S; Asefi, M; Bolourchi, M

    1999-08-01

    One of the most important and prevalent isotopes of radium (Ra) in the human food chain, and especially in drinking water, is 226Ra. To determine the contribution of this radionuclide to the annual effective dose to the public in Iran, a national program for determination of this radionuclide was established. Over 500 water samples from different surface and ground water supplies including wells, rivers and springs, as well as hot springs and sea water from the Caspian Sea and Persian Gulf have been analyzed. An emanation method with a minimum detection limit of less than 2 mBq L(-1) was developed and applied in this study. Unweighted mean concentrations of 3.3 mBq L(-1) and 8.0 mBq L(-1) were determined in surface and ground drinking water supplies, respectively. Based on such values, mean unweighted annual intakes of 226Ra were found to be 0.85 Bq for an infant, 1.97 Bq for a child, and 2.82 Bq for an adult, which correspond to mean unweighted annual effective doses of 0.17 microSv y(-1), 0.39 microSv y(-1), and 0.56 microSv y(-1), respectively. The mean 226Ra concentrations in hot springs were higher with a maximum of 146.5 Bq L(-1) measured in the Ab-e-Siah hot spring in Ramsar, a town on the coast of the Caspian Sea in Iran.

  20. Concentration of 210Po, 226Ra and 228Ac in non-siliceous environmental materials

    NASA Astrophysics Data System (ADS)

    Houmani, Zidan Mohamed M.; Bradley, D. A.; Maah, Mohd. Jamil; Ahmed, Zaharuddin

    2001-06-01

    The present interest concerns the possible anthropomorphic enhancement of naturally occurring radioactive material (NORM) in non-siliceous media, in particular, sediment from a river running alongside a crude oil facility and alluvial samples from the site of a now defunct minerals benefication plant. We use gamma spectrometry for 226Ra and 228Ac, and for 210Po we use alpha spectrometry in association with a hydrochloric acid based radiochemical method for the extraction of 210Po. Using 209Po to monitor polonium extraction from samples we find the concentrations of 210Po, 226Ra and 228Ac in river sediments to be in accord with typical background values (˜0.04 Bq g -1 dry), while for sub-surface soils located nearby we find the respective activity concentrations to accord with low background values (˜0.02 Bq g -1dry). For alluvial material from the site of a defunct minerals benefications plant we have found 210Po concentrations of ˜11 Bq g -1 (dry) in two of three samples and 30 Bq g -1 (dry) in the remaining sample; 226Ra and 228Ac were some several times these concentrations. In support of the methods we have adopted in present evaluations we find IAEA-300 Baltic Sea sediment reference material to contain 210Po concentrations that are within the IAEA confidence interval for this material.

  1. Concentration of 226Ra in rocks of the southern part of Lower Silesia (SW Poland).

    PubMed

    Przylibski, Tadeusz Andrzej

    2004-01-01

    The aim of the article is to present a preliminary description of rocks in the southern part of Lower Silesia and the Sudety Mountains in particular, with regard to 226Ra content. The research demonstrates that the average content of this isotope was 40.4 Bq/kg in the rocks of the southern part of Lower Silesia, and 41.7 Bq/kg in the rocks of the Sudetes. These values are slightly higher than the mean 226Ra content in the upper part of the Earth's crust, while the measured maximum content of this isotope (244 Bq/kg) is more than twice as high as the upper range of the values most frequently recorded in the upper part of the Earth's crust. The minimum values were lower than the detection limit, which was about 1 Bq/kg. These results reflect the mosaic-like geological structure of Lower Silesia, and particularly the Sudety Mountains, the occurrence of SiO2-rich igneous rocks and the products of their metamorphism, as well as numerous manifestations of uranium mineralisation or even deposital concentrations of this element. The rocks with the highest 226Ra contents include (in decreasing order): aplites, granites, gneisses and leucogranites, granite-gneisses, granodiorites and rhyolites, and, finally, mudstones. The lowest values of 226Ra content, on the other hand, were measured in sandstones, marls and conglomerates, and extremely low-in marbles and quartzites. The results show that background values of 226Ra content in the rocks of the southern part of Lower Silesia fall within a range from several to about 100 Bq/kg, which is the same as the range most frequently recorded in the upper part of the Earth's crust. Distribution of these values has log-normal character. The research demonstrates that the southern part of Lower Silesia, and the Sudetes in particular, may be marked by an increased radon potential. Particularly liable areas are: the Karkonosze granite massif, especially in its border zones, the Ladek-Snieznik and the Izera massifs, especially in their

  2. Microdistribution and local dosimetry of /sup 226/Ra in trabecular bone of the beagle

    SciTech Connect

    Polig, E.; Jee, W.S.; Dell, R.B.; Johnson, F.

    1988-11-01

    Sections of lumbar vertebral bodies of young adult beagle dogs have been analyzed autoradiographically to characterize and quantify the local distribution of 226Ra by means of a scanning microscope photometer. The animals received a single injection of 355 kBq/kg body weight and were serially sacrificed at 5 to 1381 days postinjection. Hotspot concentrations decreased from about 51 kBq/g bone at 5 days to 20 kBq/g at 1381 days postinjection. The diffuse concentration changed from 8.3 to 1.9 kBq/g. The mean 226Ra concentration in the trabecular areas scanned was initially higher and at the end of the observation period lower than the average calculated for the whole lumbar vertebral column. Density and area of, and fraction of bone activity in, hotspots virtually remained constant. With time hotspots tended to become translocated into bone volume. Mean dose rates to lining cells from both hotspots and diffuse labels decreased from about 210 mGy/d at early postinjection times to 105 mGy/d. This corresponds to 2.5 to 1.1 times the average skeletal dose rate. A discussion of the level of irradiation in terms of hit frequencies shows that osteoblasts in the initial phase of hotspot formation receive about 60 hits to their nucleus for the duration of bone formation. After about 6 months, however, the 226Ra concentration in new bone and the corresponding hit frequency appears to be low enough that interference with bone formation is unlikely. Morphometric measurements showed that abnormal bone accretion and thickening of trabeculae occurred. This was interpreted as an imbalance between bone formation and resorption. Both formation and resorption seem to be substantially lowered compared to control animals.

  3. Minimum speed limit for ocean ridge magmatism from 210Pb-226Ra-230Th disequilibria.

    PubMed

    Rubin, K H; van der Zander, I; Smith, M C; Bergmanis, E C

    2005-09-22

    Although 70 per cent of global crustal magmatism occurs at mid-ocean ridges-where the heat budget controls crustal structure, hydrothermal activity and a vibrant biosphere-the tempo of magmatic inputs in these regions remains poorly understood. Such timescales can be assessed, however, with natural radioactive-decay-chain nuclides, because chemical disruption to secular equilibrium systems initiates parent-daughter disequilibria, which re-equilibrate by the shorter half-life in a pair. Here we use 210Pb-226Ra-230Th radioactive disequilibria and other geochemical attributes in oceanic basalts less than 20 years old to infer that melts of the Earth's mantle can be transported, accumulated and erupted in a few decades. This implies that magmatic conditions can fluctuate rapidly at ridge volcanoes. 210Pb deficits of up to 15 per cent relative to 226Ra occur in normal mid-ocean ridge basalts, with the largest deficits in the most magnesium-rich lavas. The 22-year half-life of 210Pb requires very recent fractionation of these two uranium-series nuclides. Relationships between 210Pb-deficits, (226Ra/230Th) activity ratios and compatible trace-element ratios preclude crustal-magma differentiation or daughter-isotope degassing as the main causes for the signal. A mantle-melting model can simulate observed disequilibria but preservation requires a subsequent mechanism to transport melt rapidly. The likelihood of magmatic disequilibria occurring before melt enters shallow crustal magma bodies also limits differentiation and heat replenishment timescales to decades at the localities studied.

  4. Natural radioactivity of 226Ra and 228Ra in thermal and mineral waters in Croatia.

    PubMed

    Bituh, Tomislav; Marovic, Gordana; Petrinec, Branko; Sencar, Jasminka; Franulovic, Iva

    2009-01-01

    Thermal waters are known as valuable natural resources of a country. They contain certain degree of natural radioactivity attributable to the elements of the uranium and thorium natural decay series. Among these elements, the most radiotoxic and the most important is radium that exists in several isotopic forms (226Ra and 228Ra). The focus of attention was the content of radium in samples of thermal and mineral spring water from several spas in Croatia. These waters are mainly used for medical, bathing and recreational purposes, and some of them are used for drinking. Measured activity concentrations of 226Ra ranged from 87 to 6200 mBq l(-1) which, in some springs, exceed the maximal permissible level of 1 Bq l(-1) for drinking water. Measured activity concentrations of 228Ra ranged from 23 to 3480 mBq l(-1). The study showed that radium content for the investigated thermal and mineral waters is below the levels at which negative consequences would arise due to ingestion.

  5. Bone tumor location in dogs given skeletal irradiation by {sup 239}Pu or {sup 226}Ra

    SciTech Connect

    Lloyd, R.D.; Taylor, G.N.; Miller, S.C.

    1997-10-01

    Statistical analyses have indicated that there was a significant difference between dogs injected with bone volume-seeking {sup 226} Ra as compared to those given bone surface-seeking {sup 239}Pu with respect to location within the skeleton of 334 radiation-induced primary bone malignancies. Corresponding differences also were event when dogs given bone volume-seeking {sup 90}Sr or bone surface-seeking {sup 241}Am, {sup 228}Th {sup 248,252}Cf, or {sup 224}Ra (which decays mostly on bone surfaces because of its short, 3.6 d half time) were included along with the {sup 226}Ra or {sup 239}Pu, respectively (562 total tumors). Further analysis suggested that higher values of percent red marrow (M) and bone turnover rate (R) are correlated with increased probability. of tumor appearance at a particular location within the skeleton for the surface seekers. Proportionately higher values of M and R are associated with skeletal sites containing mostly trabecular bone as compared to those with mostly compact (cortical) bone. Coefficients of determination (r{sup 2}) for the relationship between percent of total tumors vs the combination of percent red marrow and turnover rate (= MR) was about 0.7 for the surface seekers but only about 0.1 for the volume seekers. This indicates that the neoplastic effects of surface seekers, but not volume seekers, are associated with the presence of trabecular bone at the various sites of radio nuclide deposition within the skeleton. 10 refs., 3 tabs.

  6. New dosimetry for childhood skin hemangioma treatments with (226)Ra needles or tubes.

    PubMed

    Lundell, Marie; Karlsson, Mattias; Carlsson Tedgren, Åsa

    2015-07-01

    The Stockholm Hemangioma Cohort is important for evaluation of late effects after exposure to ionizing radiation during childhood. Dose estimates in this cohort were based on both measurements and calculations using an old treatment planning system. We compare previously published and calculated dose estimates with new ones, obtained by Monte Carlo simulations, which mimic the hemangioma treatments with (226)Ra needles and tubes. The distances between the (226)Ra sources and the thyroid and breasts, respectively, were reassessed. The Monte Carlo calculations showed significantly lower dose values than those obtained earlier. The differences depended both on the modeling of the sources and on further individualized distances from the sources. The mean value of the new calculated doses was 25% of the old breast doses and 46% of the old thyroid doses. New dosimetry for hemangioma treatments gives significantly lower organ doses for the few cases receiving the highest absorbed dose values. This implies that radiation risk estimates will increase and have to be recalculated. For retrospective studies it is now possible to calculate organ doses from radium treatments using modern treatment planning systems by modeling the source geometry carefully and apply the TG-43 formalism. It is important to be aware of the large uncertainties in calculated absorbed dose values. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Techniques for precise mapping of 226Ra and 228Ra in the ocean

    NASA Astrophysics Data System (ADS)

    Moore, Willard S.; Key, Robert M.; Sarmiento, Jorge L.

    1985-01-01

    Improvements in the analyses of 226Ra and 228Ra in seawater made possible by better extraction and processing techniques reduce significantly the errors associated with these measurements. These improvements and the extensive sampling for Ra isotopes conducted on the TTO North Atlantic Study should enable us to use the distribution of 228Ra to study mixing processes on a 3-15 year time scale in both the upper and deep North Atlantic. The 228Ra profiles already analyzed show a closer resemblance to GEOSECS tritium data than to TTO tritium data in the upper ocean. This is because the transient tracer tritium was responding on a 10-year time scale during GEOSECS and a 20-year time scale during TTO. The steady state tracer 228Ra should always respond on a time scale of 8 years. Thus the 228Ra data obtained on TTO should provide a means to extend the features of the GEOSECS tritium field to the regions of the TTO study. The 226Ra data are of high enough quality to identify features associated with different water masses. Changes in the positions of the deep-water masses since the GEOSECS cruise are revealed by the 226Radata.

  8. Determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in drinking water using a single sample preparation procedure.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail P

    2005-12-01

    The current federal and New Jersey State regulations have greatly increased the number of gross alpha and radium tests for public and private drinking water supplies. The determination of radium isotopes in water generally involves lengthy and complicated processes. In this study, a new approach is presented for the determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in water samples. The method includes a single sample preparation procedure followed by alpha counting and gamma-ray spectroscopy. The sample preparation technique incorporates an EPA-approved co-precipitation methodology for gross alpha determination with a few alterations and improvements. Using 3-L aliquots of sample, spiked with 133Ba tracer, the alpha-emitting radionuclides are isolated by a BaSO4 and Fe(OH)3 co-precipitation scheme. First the gross alpha-particle activity of the sample is measured with a low-background gas-flow proportional counter, followed by radium isotopes assay by gamma-ray spectroscopy, using the same prepared sample. Gamma-ray determination of 133Ba tracer is used to assess the radium chemical recovery. The 224Ra, 226Ra, and 228Ra activities in the sample are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb/214Bi, and 228Ac, respectively. In cases where 224Ra determination is required, the gamma-ray counting should be performed within 2-4 d from sample collection. To measure 226Ra activity in the sample, the gamma-ray spectroscopy can be repeated 21 d after sample preparation to ensure that 226Ra and its progeny have reached the equilibrium state. At this point, the 228Ac equilibration with parent 228Ra is already established. Analysis of aliquots of de-ionized water spiked with NIST-traceable 230Th, 224Ra, 226Ra, and 228Ra standards demonstrated the accuracy and precision of this method. Various performance evaluation samples were also assayed for gross alpha as well as radium isotope activity determination using this procedure and the

  9. Comparative Analysis Of {sup 226}Ra Soil-To-Plant Transfer In Cabbage Grown In Various Regions

    SciTech Connect

    Madruga, M. J.; Carvalho, F. P.; Silva, L.; Gouveia, J.

    2008-08-07

    The transfer of {sup 226}Ra from soil to cabbage was compared amongst regions, namely the surroundings of Urgeirica uranium milling tailings (GE), regions with past uranium mining activities (GN1), and regions with no uranium mining activities and no uranium deposits (GN2). Results show a slight increase of the concentration ratio values at low radium concentration in soils. Statistical analysis of the mean {sup 226}Ra activity concentrations in soil and cabbage for the three regions was carried out. The comparison of {sup 226}Ra activity concentrations in soils indicated no difference (p>0.05), between GE and GN2 and significant differences (p<0.05) between GE and GN1 and between GN1 and GN2. Similar statistical results were obtained for {sup 226}Ra activity concentrations in cabbage from the same regions. It was concluded that radium Concentration Ratio (CR) for cabbage grown in the region of the main uranium milling site (GE) is of the same order of magnitude of CR in cabagge grown in background regions (GN2). However, {sup 226}Ra CR was higher in cabagge from the region with past uranium mining activities (GN1)

  10. Plant/soil concentration ratios of 226Ra for contrasting sites around an active U mine-mill.

    PubMed

    Ibrahim, S A; Whicker, F W

    1988-12-01

    Concentrations of 226Ra were determined in native vegetation and underlying substrate (soil and tailings) at various sites around a conventional open-pit, acid leach U production operation in Wyoming. Plant/soil concentration ratios (CRs) for 226Ra were estimated for various sites, including weathered tailings; a tailings impoundment shoreline; downwind from exposed tailings; a mine overburden reclamation area; and several background locations. Radium-226 concentrations for vegetation and substrate and CR values from the perturbed sites were elevated above background. The highest vegetation concentration (1.3 Bq g-1) was found in a grass which had invaded exposed, weathered tailings. Levels of 226Ra in soil and vegetation and CR values decreased with distance from the tailings impoundment edge. CR values varied significantly among sites, but few differences were found between plant species groups. The observed CR values ranged from 0.07 at the background and reclamation areas to 0.4 downwind from the tailings area. Average CR values for plants growing on exposed tailings and within one meter from the impoundment edge were 0.15 and 0.3, respectively. CR values of 226Ra for plants on tailings substrates were comparatively low in contrast to other radionuclides in the U chain. We speculate that in the case of sulfuric acid leached tailings-derived material, 226Ra is sequestered as sulfate, which is highly insoluble relative to the sulfates of the other elements (e.g., U and Th) resulting in reduced availability for plant uptake.

  11. Disequilibrium between [sup 226]Ra and supported [sup 210]Pb in a sediment core from a shallow Florida lake

    SciTech Connect

    Brenner, M.; Peplov, A.J.; Schelske, C.L. )

    1994-07-01

    [sup 210]Pb dating can be used to assign ages in lake sediment cores, calculate rates of sediment accumulation, and determine the timing of recent changes in lake-watershed ecosystems. We used low-background gamma counting to measure [sup 226]Ra and total [sup 210]Pb activity in a core from Lake Rowell, Florida. [sup 226]Ra activity was high and strongly variable throughout the core, even exceeding total [sup 210]Pb activity in recently deposited sediments. We traced one source of Ra-rich sediments to the only inflow, Alligator Creek, where stream-bottom deposits display disequilibrium between [sup 226]Ra and supported [sup 210]Pb. High and variable [sup 226]Ra activity in the Lake Rowell profile argues for direct estimates of in situ Ra in lake sediment cores from disturbed watersheds that have Ra-bearing bedrock. Isotopic disequilibrium between [sup 226]Ra and supported [sup 210]Pb makes it difficult to distinguish between supported and unsupported [sup 210]Pb activity throughout the Lake Rowell core and would require special assumptions and nonconventional dating models to establish age-depth relationships. 78 refs., 3 figs., 1 tab.

  12. Radium isotopes ((226)Ra and (228)Ra) in Na-Cl type groundwaters from Tohoku District (Aomori, Akita and Yamagata Prefectures) in Japan.

    PubMed

    Tomita, Jumpei; Zhang, Jing; Yamamoto, Masayoshi

    2014-11-01

    A total of 28 Na-Cl type groundwater samples were collected from Aomori, Akita and Yamagata Prefectures, in the Tohoku District of Japan, and their radium isotope ((226)Ra and (228)Ra) concentrations were measured along with their chemical components and stable isotope ratios (δ(2)H and δ(18)Os). The (226)Ra concentrations in groundwater samples varied widely, ranging from 8.8 to 1587 mBq kg(-1). These concentrations showed an increasing tendency with the increase of the total dissolved solid (TDS) contents. The (228)Ra/(226)Ra activity ratios were in the range from 0.3 to 4.2, with most data being around 0.5-2. These ratios were within those of (232)Th/(238)U found in granitic and related rocks and so on in Japan, indicating that Ra isotopes mainly ejected into the groundwater by the alpha-recoil process. The relationship between (226)Ra and other parameters suggested that Ra isotopes in groundwater samples in this study were mainly constrained by adsorption-desorption reactions depending on salinity with wide variation. Clear correlation between (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS observed in sulfate-free groundwater samples indicated that Ra isotopes of them were constrained by adsorption-desorption reactions depending on salinity under reducing condition. In contrast, relationship of (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS in sulfate-containing groundwater samples varied widely, and then, removal or enhanced mobility of Ra isotopes of them were observed.

  13. Transfer factor of 226Ra, 232Th and 40K from soil to Alpinia Galangal plant grown in northern Thailand

    NASA Astrophysics Data System (ADS)

    Kritsananuwat, R.; Chanyotha, S.; Kranrod, C.; Pengvanich, P.

    2017-06-01

    This paper reports the activity concentration of three natural radionuclides, 226Ra, 232Th and 40K, found in Alpinia Galangal plants which are widely used in various Asian cuisines and traditional medicine. The galangal plants and their relevant soils were collected from four provinces in the north of Thailand under natural field conditions. The activity concentration of radionuclides was determined using gamma-ray spectrometry. Soil-to-plant transfer factors (TFs) for 226Ra, 232Th and 40K were investigated in rhizome and aerial parts of the galangal plants. The activity concentration in the soils ranged from 22 to 88 Bq kg-1 for 226Ra, 27 to 157 Bq kg-1 for 232Th and 58 to 1157 Bq kg-1 for 40K. In Alpinia Galangal, the concentration ranged from < 0.2 to 2.0 Bq kg-1 for 226Ra, < 0.1 to 2.9 Bq kg-1 for 232Th and 205 to 2247 Bq kg-1 for 40K. The TF ranged from < 0.002 to 0.073 for 226Ra, < 0.001 to 0.061 for 232Th and 0.26 to 7.9 for 40K. The TFs in the aerial parts were higher than those for the rhizomes. The obtained values can be considered as a baseline data for activity concentrations of natural radionuclides and their TFs in Thailand for future environmental radiation monitoring. The Annual effective ingestion dose due to ingestion of 226Ra, 232Th and 40K in galangals is significantly below the worldwide value reported by UNSCEAR 2000.

  14. Doses from 222Rn, 226Ra, and 228Ra in groundwater from Guarani aquifer, South America.

    PubMed

    Bonotto, D M

    2004-01-01

    Groundwater samples were analysed for 222Rn, 226Ra, and 228Ra in Guarani aquifer spreading around 1 million km2 within four countries in South America, and it was found that their activity concentrations are lognormally distributed. Population-weighted average activity concentration for these radionuclides allowed to estimate a value either slightly higher (0.13 mSv/year) than 0.1 mSv for the total effective dose or two times higher (0.21 mSv/year) than this limit, depending on the choice of the dose conversion factor. Such calculation adds useful information for the appropriate management of this transboundary aquifer that is socially and economically very important to about 15 million inhabitants living in Brazil, Argentina, Uruguay and Paraguay.

  15. Use of 210Pb/ 226Ra disequilibria in the dating of deep-sea whale falls

    NASA Astrophysics Data System (ADS)

    Schuller, Daniel; Kadko, David; Smith, Craig R.

    2004-02-01

    Deep-sea whale falls, in particular the skeletal remains of whales that have sunk to the seafloor, are remarkable temporary reducing habitats. Reduced chemical species created by anaerobic microbial decay of lipid and organic compounds within the whale bone matrix fuel chemosynthetic-based communities, including bacteria, mussels, limpets, snails, and clams. Many of these species exhibit taxonomic affinities to other chemosynthetic deep-sea organisms colonizing hydrothermal vents and cold seeps. Knowledge of the timescales of whale fall community succession and persistence of these assemblages is needed to reliably estimate the abundance of whale fall habitats and to understand the dynamics of the whale fall communities and their potential roles as stepping stones for sulfophilic species. We have developed a radiochemical method based on 210Pb/ 226Ra disequilibria for estimating the ages of seafloor whale bone communities. Measurements of 210Pb/ 226Ra performed on known age bone samples yielded radioisotope ages in good agreement with the known ages. Our results indicate that this technique is valid for bones 10-85 years old (time since cetacean death). This technique, applied to multiple bones of unknown age whale falls taken from Monterey Canyon, Santa Catalina Basin, and San Nicholas Basin, constrained the upper limit ages of these systems (in 2002) to 6.3±1.0 years, 44.0±7.0 to 53.4±8.3 years, and 66.4±9.6 to 82.6±11 years, respectively. These ages were in reasonable agreement with faunal and/or skeletal observations. In addition, a preliminary lipid degradation rate was calculated for the Santa Catalina Basin whale fall using an independent time series and calibrated to the radiochemically determined age. Both radiochemical and lipid degradation evidence suggest that the whale fall microhabitat is able to support life for many decades.

  16. Influence of soil structure on the "Fv approach" applied to (238)U and (226)Ra.

    PubMed

    Blanco Rodríguez, P; Vera Tomé, F; Lozano, J C

    2017-02-01

    The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides (238)U and (226)Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides (238)U and (226)Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively.

  17. A source for measurement of the absolute intensities of 226Ra gamma-radiation in equilibrium with decay products.

    PubMed

    Kharitonov, I A; Rasko, M A; Sepman, S V; Terechtchenko, E E; Hejdelman, A M

    2002-01-01

    The design and production techniques of a gamma-ray spectrometric source of 226Ra in equilibrium with its daughter decay products have been developed. The radon emanation coefficient of the source did not exceed 0.1%. The 226Ra activity in the gamma-ray spectrometric source was measured relative to that in an alpha-particle spectrometric source by comparison of the intensities of the main gamma rays using a semiconductor gamma-ray spectrometer. The total uncertainty of the activity measurement results was 0.5% for a coverage factor of k = 2.

  18. Vertical Profiles Of {sup 226}Ra, {sup 232}Th And {sup 40}K Activities In Rocks From The Irati Formation Of The Parana Sedimentary Basin, Southern Brazil

    SciTech Connect

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution {gamma}-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Parana sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 1.84 Bq{center_dot}kg{sup -1} for {sup 232}Th and 4.20 Bq{center_dot}kg{sup -1} for {sup 40}K. Activity concentrations were determined for {sup 226}Ra (from 16.22 to 151.55 Bq{center_dot}kg{sup -1}), {sup 232}Th (from 2.93 to 56.12 Bq{center_dot}kg{sup -1}) and {sup 40}K (from 38.45 to 644.63 Bq{center_dot}kg{sup -1}). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81{+-}0.22 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 4.21{+-}0.07 Bq{center_dot}kg{sup -1} for {sup 232}Th, and 50

  19. Validation of a procedure for the analysis of (226)Ra in naturally occurring radioactive materials using a liquid scintillation counter.

    PubMed

    Kim, Hyuncheol; Jung, Yoonhee; Ji, Young-Yong; Lim, Jong-Myung; Chung, Kun Ho; Kang, Mun Ja

    2017-01-01

    An analytical procedure for detecting (226)Ra in naturally occurring radioactive materials (NORMs) using a liquid scintillation counter (LSC) was developed and validated with reference materials (zircon matrix, bauxite matrix, coal fly ash, and phosphogypsum) that represent typical NORMs. The (226)Ra was released from samples by a fusion method and was separated using sulfate-coprecipitation. Next, a (222)Rn-emanation technique was applied for the determination of (226)Ra. The counting efficiency was 238 ± 8% with glass vials. The recovery for the reference materials was 80 ± 11%. The linearity of the method was tested with different masses of zircon matrix reference materials. Using 15 types of real NORMs, including raw materials and by-products, this LSC method was compared with γ-spectrometry, which had already been validated for (226)Ra analysis. The correlation coefficient for the results from the LSC method and γ-spectrometry was 0.993 ± 0.058.

  20. Measurement of 224Ra and 226Ra activities in natural waters using a radon-in-air monitor

    USGS Publications Warehouse

    Kim, G.; Burnett, W.C.; Dulaiova, H.; Swarzenski, P.W.; Moore, W.S.

    2001-01-01

    We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn (218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made in natural waters using a single portable system for environmental monitoring of radioactivity as well as tracing of various geochemical and geophysical processes. The technique could be especially useful for the on-site rapid determination of 224Ra which has recently been found to occur at elevated activities in some groundwater wells.

  1. Microbial release of 226Ra2+ from (Ba,Ra)SO4 sludges from uranium mine wastes.

    PubMed Central

    Fedorak, P M; Westlake, D W; Anders, C; Kratochvil, B; Motkosky, N; Anderson, W B; Huck, P M

    1986-01-01

    226Ra2+ is removed from uranium mine effluents by coprecipitation with BaSO4. (Ba,Ra)SO4 sludge samples from two Canadian mine sites were found to contain active heterotrophic populations of aerobic, anaerobic, denitrifying, and sulfate-reducing bacteria. Under laboratory conditions, sulfate reduction occurred in batch cultures when carbon sources such as acetate, glucose, glycollate, lactate, or pyruvate were added to samples of (Ba,Ra)SO4 sludge. No external sources of nitrogen or phosphate were required for this activity. Further studies with lactate supplementation showed that once the soluble SO4(2-) in the overlying water was depleted, Ba2+ and 226Ra2+ were dissolved from the (Ba,Ra)SO4 sludge, with the concurrent production of S2-. Levels of dissolved 226Ra2+ reached approximately 400 Bq/liter after 10 weeks of incubation. Results suggest that the ultimate disposal of these sludges must maintain conditions to minimize the activity of the indigenous sulfate-reducing bacteria to ensure that unacceptably high levels of 226Ra2+ are not released to the environment. PMID:3752993

  2. Ce-Fe-modified zeolite-rich tuff to remove Ba(2+)-like (226)Ra(2+) in presence of As(V) and F(-) from aqueous media as pollutants of drinking water.

    PubMed

    Olguín, María Teresa; Deng, Shuguang

    2016-01-25

    The sorption behavior of the Ba(2+)-like (226)Ra(2+) in the presence of H2AsO4(-)/HAsO4(2-) and F(-) from aqueous media using Ce-Fe-modified zeolite-rich tuff was investigated in this work. The Na-modified zeolite-rich tuff was also considered for comparison purposes. The zeolite-rich tuff collected from Wyoming (US) was in contact with NaCl and CeCl3-FeCl3 solutions to obtain the Na- and Ce-Fe-modified zeolite-rich tuffs (ZUSNa and ZUSCeFe). These zeolites were characterized by scanning electron microscopy and X-ray diffraction. The BET-specific surface and the points of zero charge were determined as well as the content of Na, Ce and Fe by neutron activation analysis. The textural characteristics and the point of zero charge were changed by the presence of Ce and Fe species in the zeolitic network. A linear model described the Ba(2+)-like (226)Ra(2+) sorption isotherms and the distribution coefficients (Kd) varied with respect to the metallic species present in the zeolitic material. The As(V) oxianionic chemical species and F(-) affected this parameter when the Ba(2+)-like (226)Ra(2+)-As(V)-F(-) solutions were in contact with ZUSCeFe. The H2AsO4(-)/HAsO4(2-) and F(-) were adsorbed by ZUSCeFe in the same amount, independent of the concentration of Ba(2+)-like (226)Ra(2+) in the initial solution. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Low impact of exposure to environmentally relevant doses of 226Ra in Atlantic cod (Gadus morhua) embryonic cells.

    PubMed

    Olsvik, Pål A; Berntssen, Marc H G; Hylland, Ketil; Eriksen, Dag Ø; Holen, Elisabeth

    2012-07-01

    The aim of this study was to investigate whether (226)Ra, a radionuclide present in produced water from oil platforms in the North Sea and other offshore drilling areas, could affect vulnerable early life stages of Atlantic cod (Gadus morhua). Blastula-stage embryonic cells (EC) from fertilized eggs of Atlantic cod were isolated and exposed to environmental relevant concentrations of (226)Ra and transcription of selected genes quantified. The results showed a weak, but significant up-regulation of GPx3 and HSP70 transcripts after 48 h of exposure to 2.11 Bq/L. In EC exposed to three (226)Ra concentrations (2.11, 23 and 117 Bq/L) for 12 h, metallothionein, HSP90AA, thioredoxin and caspase 8 were significantly up-regulated in cells exposed to 117 Bq/L, whereas thioredoxin was also significantly up-regulated in EC exposed to 23 Bq/L. When EC were exposed to the same (226)Ra concentrations for 48 h, only heme oxygenase was significantly up-regulated in the 23 Bq/L exposure group. The results suggest that environmentally relevant activities of (226)Ra may induce oxidative stress and apoptosis in fish ECs. Exposure of Atlantic cod EC to Cd, selected as a model toxicant, supported the ability of EC around blastula stage to respond to toxicants by altered transcription. Due to dilution, environmentally relevant concentrations of radionuclides present in produced water would be expected to pose a minor threat to early life stages of fish. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Distribution of (226)Ra-(210)Pb-(210)Po in marine biota and surface sediments of the Red Sea, Sudan.

    PubMed

    Sirelkhatim, D A; Sam, A K; Hassona, R K

    2008-12-01

    Activity concentration levels and ratios of (226)Ra, (210)Pb and (210)Po are presented in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of PortSudan harbour, Sudan. The analyses were performed adopting alpha-spectrometry, liquid scintillation and Cerenkov counting techniques. Surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of (210)Pb and (210)Po with respect to their progenitor (226)Ra as it is evident from the activity ratios of (210)Pb/(226)Ra (3.03+/-1.79) and (210)Po/(226)Ra (2.23+/-1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2Bq/kg and 21.9Bq/kg dry weight, respectively. Similarly, the highest concentration of (210)Po was met in Favites at 38.7Bq/kg followed by brown algae, Cystoseria sp., at 32.6Bq/kg. There is no variation seen among algal species for (210)Pb uptake, however, converse to radium and polonium, Favites (coral) was found to contain the minimum concentration of lead (3.88Bq/kg). In most species there is preferential accumulation of polonium over its parent radium as indicated by (210)Po:(226)Ra activity ratio with Cystoseria (brown algae) showing the highest value at 8.81. On the other hand, (210)Po:(210)Pb activity concentration ratio revealed that coral species Favites (9.97) and the brown algae Sargassum (1.85) have a greater tendency to accumulate (210)Po over (210)Pb, while in the rest of species; this ratio is less than unity.

  5. Soft-tissue tumors among beagles injected with {sup 226}Ra

    SciTech Connect

    Lloyd, R.D.; Taylor, G.N.; Angus, W.

    1994-03-01

    A total of 409 primary soft-tissue tumors (189 malignant) occurred among 87 of 120 young adult beagles (72.5%) injected with {sup 226}Ra in eight dose levels ranging from 0.2-440 kBq kg{sup -1} body mass, while a total of 565 primary soft-tissue tumors (208 of them malignant) were seen among 117 of 133 control beagles not given radioactivity (88%). Because the p-value for the difference in these two percentages was >0.05, further comparisons were not made of all tumor locations or types taken together but only of the individual tumor locations or types. There was a clear excess of malignant tumors and all tumors (benign plus malignant) in the eye among dogs injected with radium (p < 0.05, p < 0.01, respectively), but the occurrence of all the other types of soft-tissue tumors was not greater in irradiated vs. control dogs (p > 0.05). This was also true for hematopoietic tumor types (including just one leukemia in a control and none in irradiated dogs) in which there was no difference between controls and dogs given radium. 25 refs., 7 tabs.

  6. Thermoluminescence and excess 226Ra decay dating of late Quaternary fluvial sands, East Alligator River, Australia

    NASA Astrophysics Data System (ADS)

    Murray, Andrew; Wohl, Ellen; East, Jon

    1992-01-01

    Thermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.

  7. Leaching of 226Ra from U mill tailings by sulfate-reducing bacteria.

    PubMed

    Landa, E R; Miller, C L; Updegraff, D M

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum 226Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed.

  8. Direct measurement of alpha emission probabilities in the decay of (226)Ra.

    PubMed

    Marouli, M; Pommé, S; Van Ammel, R; García-Toraño, E; Crespo, T; Pierre, S

    2017-07-01

    High-resolution alpha-particle spectrometry was performed to determine the main alpha-particle emission probabilities in the decay of (226)Ra. Thin, homogeneous sources were prepared by electrodeposition on stainless steel disks. Alpha spectra with an energy resolution of 20keV were obtained in three laboratories and analysed with different deconvolution algorithms. In two set-ups, a magnet system was used to deflect conversion electrons to avoid their coincidental detection with the alpha particles. Spectra taken at close range without a magnet system yielded biased results which cannot be fully compensated by statistical corrections for coincidence summing. The derived emission probabilities of the three main alpha decays are 94.07 (1)%, 5.93 (1)%, and 0.0059 (15)%, respectively. They are in excellent agreement with calculated values derived from the P(γ+ce) decay scheme balance, which solves the existing discrepancy problem with two previous direct measurements published in literature. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Measurement of activity concentrations of 40K, 226Ra and 232Th for assessment of radiation hazards from soils of the southwestern region of Nigeria.

    PubMed

    Ajayi, Oladele Samuel

    2009-08-01

    Activity concentrations of the selected radionuclides (40)K, (226)Ra and (232)Th were measured in surface soil samples collected from 38 cities in the southwest region of Nigeria by means of gamma spectroscopy with a high-purity germanium detector. Measured activity concentration values of (40)K varied from 34.9 +/- 4.4 to 1,358.6 +/- 28.5 Bq kg(-1) (given on a dry mass (DM) basis) with a mean value of 286.5 +/- 308.5 Bq kg(-1); that of (226)Ra varied from 9.3 +/- 3.7 to 198.1 +/- 13.8 Bq kg(-1) with a mean value of 54.5 Bq kg(-1) and a standard deviation of 38.7 Bq kg(-1), while that of (232)Th varied from 5.4 +/- 1.1 to 502.0 +/- 16.5 Bq kg(-1) with a mean value of 91.1 Bq kg(-1) and standard deviation of 100.9 Bq kg(-1). The mean activity concentration values obtained for (226)Ra and (232)Th are greater than the world average values reported by the United Nations Scientific Committee on Effects of Atomic Radiation for areas of normal background radiation. Radiological indices were estimated for the radiation/health hazards of the natural radioactivity of all soil samples. Estimated absorbed dose rates in air varied from 12.42 +/- 2.25 to 451.33 +/- 19.06 nGy h(-1), annual outdoor effective dose rates from 0.015 +/- 0.003 to 0.554 +/- 0.023 mSv year(-1), internal hazard index from 0.10 +/- 0.03 to 3.02 +/- 0.16, external hazard index from 0.07 +/- 0.01 to 2.60 +/- 0.11, representative level index from 0.19 +/- 0.03 to 6.84 +/- 0.29, activity index from 0.09 +/- 0.02 to 3.42 +/- 0.15, and radium equivalent activity from 26.95 +/- 5.04 to 963.15 +/- 41.87 Bq kg(-1). Only the mean value of the representative level index exceeds the limit for areas of normal background radiation. All other indices show mean values that are lower than the recommended limits.

  10. Concurrent determination of 224Ra, 226Ra, 228Ra, and unsupported 212Pb in a single analysis for drinking water and wastewater: dissolved and suspended fractions.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail

    2004-02-01

    A technique has been developed for the measurement of 224Ra, 226Ra, 228Ra, and unsupported 2t2Pb concurrently in a single analysis. The procedure can be applied to both drinking water and wastewater, including the dissolved and suspended fractions of a sample. For drinking water samples, using 3-L aliquots, the radium isotopes are isolated by a fast PbSO4 co-precipitation and then quantified by gamma-ray spectroscopy. The radium isotopes 224Ra, 226Ra, and 228Ra are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb (and/or 214Bi), and 228Ac, respectively. Because of the short half-life of 224Ra (T1/2 = 3.66 d), the precipitate should be counted within 4 d of the sample collection date. In case the measurement of unsupported 212Pb (T1/2 = 10.64 h) is required, the gamma-ray analysis should be initiated as soon as possible, preferably on the same day of collection. The counting is repeated after about 21 d to ensure the 226Ra progeny are in equilibrium with their parent. At this point, the 228Ac equilibration with its 228Ra parent is already established. In the case of samples containing suspended materials, an aliquot of sample is filtered and then the filtrate is treated as described above for drinking water samples. The suspended fraction of sample, collected on the filter, is directly analyzed by gamma-ray spectroscopy with no further chemical separation. Aliquots of de-ionized water spiked with various radium standards were analyzed to check the accuracy and precision of the method. In addition, analysis results of actual samples using this method were compared with the ones performed using U.S. Environmental Protection Agency-approved procedures, and the measured values were in close agreement. This method simplifies the analytical procedures and reduces the labor while achieving the precision, accuracy, and minimum detection concentration requirements of EPA's Regulations.

  11. (The determination of sup 222 Rn flux from soils based on sup 210 Pb and sup 226 Ra disequilibrium)

    SciTech Connect

    Turekian, K.K.

    1991-01-01

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  12. The Concentrations of {sup 40}K, {sup 226}Ra and {sup 232}Th in Soil Sample in Osmaniye (Turkey)

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Kara, A.; Mavi, B.; Karaboerklue, S.

    2011-12-26

    The {sup 40}K, {sup 226}Ra and {sup 232}Th concentration is due to the magmatic structure of the earth and it can be varied from place to place. Osmaniye is located in the Eastern side of Mediteranean Region. It holds the climatic characteristics of the same region and arises with Middle Taurus Mountains from west to North and with Amonos Mounations in East and West-east parts and is situated between 35 deg. .52'-36 deg. .42' east longitudes and 36 deg. .57'-37 deg. .45' north latitudes. In this study, the natural radioactivity concentrations {sup 40}K, {sup 226}Ra and {sup 232}Th in some soil samples collected in Osmaniye have been investigated. The measurements have been performed using 3x3{sup ''} NaI(Tl) detector system.

  13. Field analyses of (238)U and (226)Ra in two uranium mill tailings piles from Niger using portable HPGe detector.

    PubMed

    Déjeant, Adrien; Bourva, Ludovic; Sia, Radia; Galoisy, Laurence; Calas, Georges; Phrommavanh, Vannapha; Descostes, Michael

    2014-11-01

    The radioactivities of (238)U and (226)Ra in mill tailings from the U mines of COMINAK and SOMAÏR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The (238)U and (226)Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. 40K, 115Cs and 226Ra Soil and Plant Content in Seminatural Grasslands of Central Argentina

    NASA Astrophysics Data System (ADS)

    Ayub, J. Juri; Velasco, R. H.; Rizzotto, M.; Quintana, E.; Aguiar, J.

    2008-08-01

    Activity concentrations of 40K, 226Ra and 137Cs have been analyzed in soil and plant samples, collected in permanent grassland in central Argentina. Two near areas (A1 and A2) under field conditions with soil undisturbed at least in the last four decades were selected. For each of the three studied radionuclides we do not find differences in the inventories between both areas. The inventories range from 143 kBq m-2 to 197 kBq m-2 for 40K and from 13 kBq m-2 to 18 kBq m-2 for 226Ra. The vertical distributions of 40K and 226Ra are uniform through de soil profile. For 137Cs the inventories range from 0.33 kBq m-2 to 0.73 kBq m-2. In spite of 137Cs inventories are similar in both areas the distribution through vertical profile is different. 137Cs activity concentration has a maximum for layers 5-10 cm depth in A1 and 10-15 cm depth in A2. For deeper layers both areas show similar activity concentrations. The diffusion coefficient (Ds) and convection velocity (vs) are estimated with a convection-diffusion model. Ds values are in the range reported in the bibliography, while vs values are one order of magnitude higher. After 40 years most 137Cs fallout is still in the layer 10-15 cm depth. The great penetration of 137Cs (25 cm) in these soils may be the result of a high sand and low fine materials content. 137Cs and 226Ra were not detected in grass samples. Activity concentration of 40K in vegetal samples ranges from 116 Bq kg-1 to 613 Bq kg-1. The TF values obtained for 40K show a lognormal distribution and ranges from 0.05 to 0.42.

  15. [About the contents of 40K, 226Ra and 232Th in forest soils of the Republic of Belarus].

    PubMed

    Perevolotskiĭ, A N; Perevolotskaia, T V

    2014-01-01

    The specific activity of 40K, 232Th and 226Ra in forest soil ecotopes (A2-B2-C2-D2) has been investigated. When the fertility of the soil increases from A2 to D2, then the specific activity of 40K increases in the rooting zone of the soil from 275 ± 6.9 up to 499 ± 11 Bq/kg, 232Th--from 11.8 ± 0.5 to 17.1 ± 1.1 Bq/kg, 226Ra- from 19.2 γ 0.8 to 27.9 ± 1.5 Bq/kg. The calculated capacity of the absorbed dose of γ-radiation conditioned by 40K, 232Th and 226Ra increases from A2 to D2 from 27.5 ± 0.5 to 44.1 ± 1.1 nGy / h at the height of 1 m.

  16. /sup 238/U, /sup 226/Ra and /sup 210/Pb in some vent waters of the Galapagos spreading center

    SciTech Connect

    Krishnaswami, S.; Turekian, K.K.

    1982-08-01

    The concentrations of /sup 226/Ra, /sup 238/U and /sup 210/Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of approx.2.5--16 /sup 0/C. The /sup 226/Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg /sup 0/C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal /sup 226/Ra flux less than 5% of that required to sustain the oceanic inventory. /sup 238/U concentration in waters <9 /sup 0/C is the same as that in ambient sea water whereas water hotter than approx.9 /sup 0/C shows a decreasing trend with temperature to zero /sup 238/U at approx.29 /sup 0/C. /sup 210/Pb concentration in Mussel Bed increases with temperature, and extrapolated to approx.350 /sup 0/C yields a /sup 210/Pb concentration considerably less than that expected from /sup 222/Rn decay and basalt alteration.

  17. (226)Ra, (232)Th and (40)K contents in soil samples from Garhwal Himalaya, India, and its radiological implications.

    PubMed

    Ramola, R C; Gusain, G S; Badoni, Manjari; Prasad, Yogesh; Prasad, Ganesh; Ramachandran, T V

    2008-09-01

    The exposure of human beings to ionising radiation from natural sources is a continuing and inescapable feature of life on earth. Natural radionuclides are widely distributed in various geological formations and ecosystems such as rocks, soil groundwater and foodstuffs. In the present study, the distribution of (226)Ra, (232)Th and (40)K was measured in soil samples collected from different lithological units of the Thauldhar and Budhakedar regions of Garhwal Himalaya, India. The collected soil samples were analysed using gamma ray spectrometry. The activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K in these soil samples were found to vary from below detection level (BDL) to 131 +/- 18 Bq kg(-1), 9 +/- 6 to 384 +/- 53 Bq kg(-1) and 471 +/- 96 to 1406 +/- 175 Bq kg(-1), respectively. The distribution of radionuclides depends upon the rock formation and chemical properties within the earth. The activity concentrations vary widely depending on the sample origin. The external absorbed gamma dose rates due to (226)Ra, (232)Th and (40)K were found to vary from 49 to 306 nGy h(-1). The average radium equivalent activity from these soil samples was 300 Bq kg(-1).

  18. Measurement of 226Ra, 232Th, 137Cs and 40K activities of Wheat and Corn Products in Ilam Province – Iran and Resultant Annual Ingestion Radiation Dose

    PubMed Central

    CHANGIZI, Vahid; SHAFIEI, Elham; ZAREH, Mohammad Reza

    2013-01-01

    Background: Background: Natural background radiation is the main source of human exposure to radioactive material. Soils naturally have radioactive mineral contents. The aim of this study is to determine natural (238 U, 232 Th, 40 K) and artificial (137 Cs) radioactivity levels in wheat and corn fields of Eilam province. Methods: HPGe detector was used to measure the concentration activity of 238 U and 232 Th series, 40 K and 137 Cs in wheat and corn samples taken from different regions of Eilam province, in Iran. Results: In wheat and corn samples, the average activity concentrations of 226 Ra, 232 Th, 40 K and 137 Cs were found to be 1, 67, 0.5, 91.73, 0.01 and 0.81, 0.85, 101.52, 0.07 Bq/kg (dry weight), respectively. H ex and H in in the present work are lower than 1. The average value of H ex was found to be 0.02 and 0.025 and average value of H in to be found 0.025 and 0.027 in wheat fields samples and corn samples in Eilam provinces, respectively. The obtained values of AGDE are 30.49 mSv/yr for wheat filed samples and 37.89 mSv/yr for corn samples; the AEDE rate values are 5.28 mSv/yr in wheat filed samples and this average value was found to be 6.13 mSv/yr in corn samples in Eilam. Transfer factors (TFs) of long lived radionuclide such as 137 Cs, 226 Ra, 232 Th and 40 K from soils to corn and wheat plants have been studied by radiotracer experiments. Conclusion: The natural radioactivity levels in Eilam province are not at the range of high risk of morbidity and are under international standards. PMID:26056646

  19. U-isotopes and (226)Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas.

    PubMed

    Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

    2016-07-01

    Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ((238)U, (235)U and (234)U) and (226)Ra by alpha spectrometry were determined. The activity concentration of (238)U presented a large variation from around 1.1 to 65 mBq L(-1). Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The (234)U/(238)U activity ratios were higher than unity for all samples (1.1-3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. (226)Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10(2) mBq L(-1)); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed (226)Ra/(234)U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). (226)Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest (234)U/(238)U activity ratios, probably due to fast uniform bulk mineral dissolution

  20. MSFIA-LOV system for (226)Ra isolation and pre-concentration from water samples previous radiometric detection.

    PubMed

    Rodríguez, Rogelio; Borràs, Antoni; Leal, Luz; Cerdà, Víctor; Ferrer, Laura

    2016-03-10

    An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of (226)Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The (226)Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection). The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h(-1)). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The (226)Ra minimum detectable activities (LSC: 0.004 Bq L(-1); LBPC: 0.02 Bq L(-1)) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. (226Ra)/(230Th) Excess Generated in the Lower Crust: Implications for Magma Transport Rates in Arc Settings

    NASA Astrophysics Data System (ADS)

    Dufek, J. D.; Cooper, K. M.

    2004-12-01

    226Ra-excesses in arc magmas have been interpreted to result from flux melting of the mantle above subducting slabs and subsequent fast ascent rates of magma from slab to surface, up 1000 m/yr and higher. Implied by this hypothesis is that the magma has not stalled at any depth for long periods of time, limiting the amount of time for assimilation of crustal material and homogenization of magmas. However, mixing of mantle melts with mid to lower crustal melts has been inferred in numerous localities, especially in continental arc settings. In addition, very short residence times may be in conflict with crystal residence of thousands to tens of thousands of years in arc lavas. We present calculations that demonstrate that incongruent melting of the lower crust could either maintain or augment mantle-derived Ra-excesses and so reduce vertical transport rates to 10 m/yr or less. In particular, we found that dehydration melting of amphibolite can produce modeled 226Ra-excesses greater than 300 percent with corresponding 230Th-excesses of approx. 14 percent. Both the modal percentage of garnet and melt fraction contribute to the degree of Ra-excess, and a wide range of garnet compositions can produce significant disequilibria. Mixtures of such an amphibolite dehydration melt with mantle melts will likely retain a 238U-excess (subducted slab) signature, although lower crustal melting without such mixing could help explain some of the enigmatic silicic magmas observed that have 230Th-excesses. This amphibolite dehydration melting process will also produce elevated Sr/Y and La/Yb ratios, similar to those observed in several arc settings, that may distinguish these magmas from those with 226Ra-excesses produced by slab-dewatering alone.

  2. Seasonal changes in submarine groundwater discharge to coastal salt ponds estimated using 226Ra and 228Ra as tracers

    USGS Publications Warehouse

    Hougham, A.L.; Moran, S.B.; Masterson, J.P.; Kelly, R.P.

    2008-01-01

    Submarine groundwater discharge (SGD) to coastal southern Rhode Island was estimated from measurements of the naturally-occurring radioisotopes 226Ra (t1/2 = 1600??y) and 228Ra (t1/2 = 5.75??y). Surface water and porewater samples were collected quarterly in Winnapaug, Quonochontaug, Ninigret, Green Hill, and Pt. Judith-Potter Ponds, as well as nearly monthly in the surface water of Rhode Island Sound, from January 2002 to August 2003; additional porewater samples were collected in August 2005. Surface water activities ranged from 12-83??dpm 100??L- 1 (60??dpm = 1??Bq) and 21-256??dpm 100??L- 1 for 226Ra and 228Ra, respectively. Porewater 226Ra activities ranged from 16-736??dpm 100??L- 1 (2002-2003) and 95-815??dpm 100??L- 1 (2005), while porewater 228Ra activities ranged from 23-1265??dpm 100??L- 1. Combining these data with a simple box model provided average 226Ra-based submarine groundwater fluxes ranging from 11-159??L m- 2 d- 1 and average 228Ra-derived fluxes of 15-259??L m- 2 d- 1. Seasonal changes in Ra-derived SGD were apparent in all ponds as well as between ponds, with SGD values of 30-472??L m- 2 d- 1 (Winnapaug Pond), 6-20??L m- 2 d- 1 (Quonochontaug Pond), 36-273??L m- 2 d- 1 (Ninigret Pond), 29-76??L m- 2 d- 1 (Green Hill Pond), and 19-83??L m- 2 d- 1 (Pt. Judith-Potter Pond). These Ra-derived fluxes are up to two orders of magnitude higher than results predicted by a numerical model of groundwater flow, estimates of aquifer recharge for the study period, and values published in previous Ra-based SGD studies in Rhode Island. This disparity may result from differences in the type of flow (recirculated seawater versus fresh groundwater) determined using each technique, as well as variability in porewater Ra activity. ?? 2007 Elsevier B.V. All rights reserved.

  3. {sup 40}K, {sup 115}Cs and {sup 226}Ra Soil and Plant Content in Seminatural Grasslands of Central Argentina

    SciTech Connect

    Ayub, J. Juri; Velasco, R. H.; Rizzotto, M.; Quintana, E.; Aguiar, J.

    2008-08-07

    Activity concentrations of {sup 40}K, {sup 226}Ra and {sup 137}Cs have been analyzed in soil and plant samples, collected in permanent grassland in central Argentina. Two near areas (A1 and A2) under field conditions with soil undisturbed at least in the last four decades were selected. For each of the three studied radionuclides we do not find differences in the inventories between both areas. The inventories range from 143 kBq m{sup -2} to 197 kBq m{sup -2} for {sup 40}K and from 13 kBq m{sup -2} to 18 kBq m{sup -2} for {sup 226}Ra. The vertical distributions of {sup 40}K and {sup 226}Ra are uniform through de soil profile. For {sup 137}Cs the inventories range from 0.33 kBq m{sup -2} to 0.73 kBq m{sup -2}. In spite of {sup 137}Cs inventories are similar in both areas the distribution through vertical profile is different. {sup 137}Cs activity concentration has a maximum for layers 5-10 cm depth in A1 and 10-15 cm depth in A2. For deeper layers both areas show similar activity concentrations. The diffusion coefficient (D{sub s}) and convection velocity (v{sub s}) are estimated with a convection-diffusion model. D{sub s} values are in the range reported in the bibliography, while v{sub s} values are one order of magnitude higher. After 40 years most {sup 137}Cs fallout is still in the layer 10-15 cm depth. The great penetration of {sup 137}Cs (25 cm) in these soils may be the result of a high sand and low fine materials content. {sup 137}Cs and {sup 226}Ra were not detected in grass samples. Activity concentration of {sup 40}K in vegetal samples ranges from 116 Bq kg{sup -1} to 613 Bq kg{sup -1}. The TF values obtained for {sup 40}K show a lognormal distribution and ranges from 0.05 to 0.42.

  4. (226)Ra dynamic lixiviation from phosphogypsum samples by an automatic flow-through system with integrated renewable solid-phase extraction.

    PubMed

    Ceballos, Melisa Rodas; Borràs, Antoni; García-Tenorio, Rafael; Rodríguez, Rogelio; Estela, José Manuel; Cerdà, Víctor; Ferrer, Laura

    2017-05-15

    The release of (226)Ra from phosphogypsum (PG) was evaluated by developing a novel tool for fully automated (226)Ra lixiviation from PG integrating extraction/pre-concentration using a renewable sorbent format. Eight leached fractions (30mL each one) and a residual fraction were analyzed allowing the evaluation of dynamic lixiviation of (226)Ra. An automatic system allows this approach coupling a homemade cell with a (226)Ra extraction/pre-concentration method, which is carried out combining two procedures: Ra adsorption on MnO2 and its posterior co-precipitation with BaSO4. Detection was carried out with a low-background proportional counter, obtaining a minimum detectable activity of 7Bqkg(-1). Method was validated by analysis of a PG reference material (MatControl CSN-CIEMAT 2008), comparing the content found in fractions (sum of leached fractions + residual fraction) to the reference value. PG samples from Huelva (Spain) were studied. (226)Ra average activity concentration of the sum of leached fractions with artificial rainwater at pH 5.4±0.2 was 105±3Bqkg(-1)d.w. representing a (226)Ra lixiviation of 37%; while at pH 2.0±0.2, it was 168±3Bqkg(-1) d.w., which represents a 50%. Also, static lixiviation, maintaining the same experimental conditions, was carried out indicating that, for both considered pH, the (226)Ra release from PG is up to 50% higher in a dynamic leaching that in a static one, may have both environmental and reutilization implications.

  5. Soil-to-root vegetable transfer factors for (226)Ra, (232)Th, (40)K, and (88)Y in Malaysia.

    PubMed

    Asaduzzaman, Kh; Khandaker, Mayeen Uddin; Amin, Y M; Bradley, D A; Mahat, R H; Nor, R M

    2014-09-01

    Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)). Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Soil features and indoor radon concentration prediction: radon in soil gas, pedology, permeability and 226Ra content.

    PubMed

    Lara, E; Rocha, Z; Santos, T O; Rios, F J; Oliveira, A H

    2015-11-01

    This work aims at relating some physicochemical features of soils and their use as a tool for prediction of indoor radon concentrations of the Metropolitan Region of Belo Horizonte (RMBH), Minas Gerais, Brazil. The measurements of soil gas radon concentrations were performed by using an AlphaGUARD monitor. The (226)Ra content analysis was performed by gamma spectrometry (high pure germanium) and permeabilities were performed by using the RADON-JOK permeameter. The GEORP indicator and soil radon index (RI) were also calculated. Approximately 53 % of the Perferric Red Latosols measurement site could be classified as 'high risk' (Swedish criteria). The Litholic Neosols presented the lowest radon concentration mean in soil gas. The Perferric Red Latosols presented significantly high radon concentration mean in soil gas (60.6 ± 8.7 kBq m(-3)), high indoor radon concentration, high RI, (226)Ra content and GEORP. The preliminary results may indicate an influence of iron formations present very close to the Perferric Red Latosols in the retention of uranium minerals. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. {sup 226}Ra and {sup 231}Pa systematics of axial MORB, crustal residence ages, and magma chamber characteristics at 9--10{degree}N East Pacific Rise

    SciTech Connect

    Goldstein, S.J.; Murrell, M.T.; Perfit, M.R.; Batiza, R.; Fornari, D.J.

    1994-06-01

    Mass spectrometric measurements of {sup 30}Th-22{sup 226}Ra and {sup 235}-U{sup 231}Pa disequilibria for axial basalts are used to determine crustal residence ages for MORB magma and investigate the temporal and spatial characteristics of axial magma chambers (AMC) at 9--10{degrees}N East Pacific Rise (EPR). Relative crustal residence ages can be calculated from variations in {sup 226}Ra/{sup 230}Th and {sup 231}Pa/{sup 235}U activity ratios for axial lavas, if (1) mantle sources and melting are uniform, and mantle transfer times are constant or rapid for axial N-MORB, and (2) {sup 231}Pa/{sup 235}U and {sup 226}Ra/{sup 230}Th in the melt are unaffected by shallow level fractional crystallization. Uniform Th, Sr, and Nd isotopic systematics and incompatible element ratios for N-MORB along the 9--10{degrees}N segment indicate that mantle sources and transfer times are similar. In addition, estimated bulk solid/melt partition coefficients for U, Th, and Pa are small, hence effects of fractional crystallization on {sup 231}Pa/{sup 235}U ratios for the melt are expected to be negligible. However, fractional crystallization of plagioclase in the AMC would lower {sup 226}Ra/{sup 230}Th ratios in the melt and produce a positive bias in {sup 226}Ra crustal residence ages for fractionated lavas.

  8. Magma differentiation rates from ( 226Ra / 230Th) and the size and power output of magma chambers

    NASA Astrophysics Data System (ADS)

    Blake, Stephen; Rogers, Nick

    2005-08-01

    We present a mathematical model for the evolution of the ( 226Ra / 230Th) activity ratio during simultaneous fractional crystallization and ageing of magma. The model is applied to published data for four volcanic suites that are independently known to have evolved by fractional crystallization. These are tholeiitic basalt from Ardoukoba, Djibouti, MORB from the East Pacific Rise, alkali basalt to mugearite from Vestmannaeyjar, Iceland, and basaltic andesites from Miyakejima, Izu-Bonin arc. In all cases ( 226Ra / 230Th) correlates with indices of fractional crystallization, such as Th, and the data fall close to model curves of constant fractional crystallization rate. The best fit rates vary from 2 to 6 × 10 - 4 yr - 1 . Consequently, the time required to generate moderately evolved magmas ( F ≤ 0.7) is of the order of 500 to 1500 yrs and closed magma chambers will have lifetimes of 1700 to 5000 yrs. These rates and timescales are argued to depend principally on the specific power output (i.e., power output per unit volume) of the magma chambers that are the sites of fractional crystallization. Equating the heat flux at the EPR to the heat flux from the sub-axial magma chamber that evolves at a rate of ca. 3 × 10 - 4 yr - 1 implies that the magma body is a sill of ca. 100 m thickness, a value which coincides with independent estimates from seismology. The similarity of the four inferred differentiation rates suggests that the specific power output of shallow magma chambers in a range of tectonic settings covers a similarly narrow range of ca. 10 to 50 MW km - 3 . Their differentiation rates are some two orders of magnitude slower than that of the basaltic Makaopuhi lava lake, Hawaii, that cooled to the atmosphere. This is consistent with the two orders of magnitude difference in heat flux between Makaopuhi and the East Pacific Rise. ( 226Ra / 230Th) data for magma suites related by fractional crystallization allow the magma differentiation rate to be estimated

  9. An improved method for the simultaneous determination of /sup 224/Ra, /sup 226/Ra and /sup 228/Ra in water, soils and sediments

    SciTech Connect

    Lucas, H.F.

    1987-01-01

    The naturally occurring concentrations of radium (/sup 226/Ra and /sup 228/Ra) in public and private water supplies have been studied for many years. Both general surveys ad local studies have established the geographical regions where well waters exceed 3 pCi/L (1-17). In general, the /sup 226/Ra was determined by the emanation method, while the /sup 228/Ra was determined from the beta activity of the /sup 228/Ac daughter. In a recent review (18) of the methods used ''a number of approved analytic methods can bear improvement, especially the method for 228Ra.'' The purpose of the work described here was to develop an improved method for the simultaneous determination of /sup 226/Ra and /sup 228/Ra. 22 refs., 3 tabs.

  10. The Dynamics of Life. I. Death from Internal Irradiation by 239Pu and 226Ra, Aging, Cancer, and Other Diseases*

    PubMed Central

    Stover, Betsy J.; Eyring, Henry

    1970-01-01

    Early in the era of atomic energy the potential of plutonium as an industrial and an environmental hazard was recognized. Thus, the Laboratory for Radiobiology was established at this University 20 years ago to compare the effects of plutonium and radium in beagles. Sufficient data have now accrued for exacting analysis. Concurrently we have formulated the steady-state theory of mutation rates which provides the necessary formalism to assess the survival data from the 239Pu and 226Ra study. Although the principal biological end point for both nuclides is the osteosarcoma, the mechanisms of nonsurvival for the two nuclides appear to be different. The success of the theory in this case suggests that application to data on irradiation of more inbred and more outbred species would prove to be exceedingly valuable. PMID:5273891

  11. A computer program integrating a multichannel analyzer with gamma analysis for the estimation of sup 226 Ra concentration in soil samples

    SciTech Connect

    Wilson, J. E.

    1992-08-01

    A new hardware/software system has been implemented using the existing three-regions-of-interest method for determining the concentration of {sup 226}Ra in soil samples for the Pollutant Assessment Group of the Oak Ridge National Laboratory. Consisting of a personal computer containing a multichannel analyzer, the system utilizes a new program combining the multichannel analyzer with a program analyzing gamma-radiation spectra for {sup 226}Ra concentrations. This program uses a menu interface to minimize and simplify the tasks of system operation.

  12. (226) RA AND (228) RA ACTIVITIES ASSOCIATED WITH AGRICULTURAL DRAINAGE PONDS AND WETLAND PONDS IN THE KANKAKEE WATERSHED, IL-IN, USA

    EPA Science Inventory

    Background radioactivity is elevated in many agricultural drainage ponds and also constructed wetland ponds in the Kankakee watershed. During 1995-1999, gross-a and -B activities were measured up to 455 and 1650 mBq L-1, respectively. 226Ra and 228Ra averaged 139 and 192 mBq L-01...

  13. (226) RA AND (228) RA ACTIVITIES ASSOCIATED WITH AGRICULTURAL DRAINAGE PONDS AND WETLAND PONDS IN THE KANKAKEE WATERSHED, IL-IN, USA

    EPA Science Inventory

    Background radioactivity is elevated in many agricultural drainage ponds and also constructed wetland ponds in the Kankakee watershed. During 1995-1999, gross-a and -B activities were measured up to 455 and 1650 mBq L-1, respectively. 226Ra and 228Ra averaged 139 and 192 mBq L-01...

  14. Precise determination of photon emission probabilities for the main X- and gamma-rays of 226Ra in equilibrium with daughters.

    PubMed

    Morel, J; Sepman, S; Rasko, M; Terechtchenko, E; Delgado, J U

    2004-01-01

    Within the context of a joint project between VNIIM (D.I. Mendeleyev Institute for Metrology) and LNHB (Laboratoire National Henri Becquerel), special 226Ra sources were prepared by VNIIM in order to determine as accurately as possible the absolute photon emission probabilities for the main X- and gamma-rays following the decay of 226Ra and daughters. The main purpose of this work was to supplement a previous joint study by Laboratorio Nacional de Metrologia das Radiaçoes Ionizantes (LNMRI) and LNHB to determine their relative values. Some specific point sources were produced for alpha-spectrometry measurements that were undertaken at VNIIM and also for gamma-ray spectrometry studies at VNIIM and LNHB. The 226Ra activity for the gamma-spectrometric sources was measured relative to the alpha-spectrometric sources by comparing the counts of the main gamma-rays. The total uncertainty of the activity for these sources was 0.2% (k = 1). Using calibrated germanium detectors, several X- and gamma-ray spectra were analyzed to determine the absolute photon emission probabilities of 226Ra in radioactive equilibrium with daughters. The results are presented and compared to other published values.

  15. Chronic exposure by ingestion of environmentally relevant doses of (226)Ra leads to transient growth perturbations in fathead minnow (Pimephales promelas, Rafinesque, 1820).

    PubMed

    Mothersill, Carmel; Smith, Richard; Lariviere, Dominic; Seymour, Colin

    2013-11-01

    To assess the impact of environmentally relevant levels of ingested (226)Ra on a common freshwater fish species. Fathead minnow (Pimephales promelas, Rafinesque) were obtained at the first feeding stage and established on a commercial fish food diet containing (226)Ra in the activity range 10 mBq/g(-1), -10,000 mBq/g(-1). They remained on this diet for 24 months and were sampled invasively at 1,6,18 and 24 months to assess growth, biochemical indices and accumulated dose and non-invasively also at 12 and 15 months to assess growth. Fish fed 10 and 100 mBq/g(-1) diet showed a small transitory deregulation of growth at 6 and 12 months. Fish fed higher activities showed less significant or insignificant effects. There was a trend at 18 months which was stronger at 24 months for the population distribution to change in all of the (226)Ra fed groups so that smaller fish were smaller and bigger fish were bigger than the controls. There were also significant differences in the ratios of protein:DNA at 24 months which were seen as a trend but were not significant at earlier time points. Fish fed a radium diet for 2 years show a small and transitory growth dysregulation at 6 and 12 months. The effects predominate at the lower activities suggesting hormetic or homeostatic adjustments. There was no effect on growth of exposure to the high activities (226)Ra. This suggests that radium does not have a serious impact on the ecology of the system and the level of radium that would be transferred to humans is very low. The results may be important in the assessment of long-term environmental impacts of (226)Ra exposure.

  16. Effect of low molecular weight organic acids on the uptake of (226)Ra by corn (Zea mays L.) in a region of high natural radioactivity in Ramsar-Iran.

    PubMed

    Nezami, Sareh; Malakouti, Mohammad Jafar; Bahrami Samani, Ali; Ghannadi Maragheh, Mohammad

    2016-11-01

    To study the benefit of including citric and oxalic acid treatments for phytoremediation of (226)Ra contaminated soils a greenhouse experiment with corn was conducted. A soil was sampled from a region of high natural (226)Ra radioactivity in Ramsar, Iran. After cultivation of corn seed and using organic acid treatments at 1, 10 and 100 mM concentrations, plants (shoots and roots) were harvested, digested and prepared to measure (226)Ra activity. Simultaneously, sequential selective extraction were performed to estimate the partitioning of (226)Ra among geochemical extraction. Results showed that the maximum uptake of (226)Ra in plants was observed in citric acid (6.3%) and then oxalic acid (6%) at 100 mM concentration. These treatments increased radium uptake by a factor of 1.5 than the control. Enhancement of radium uptake by plants was related to soil pH reduction of organic acids in comparison to control. Also, the maximum uptake of this radionuclide in all treatments was obtained in roots compared to shoots. (226)Ra fractionations results revealed that 91.8% of radium was in the residual phase of the soil and the available fractions were less than 2%. As the main percent of (226)Ra was in the residual phase of the soil in this region, it seems that organic acids had not significant effect on the uptake of (226)Ra for phytoremediation by corn in this condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Radionuclide ((226)Ra, (232)Th, (40)K) accumulation among plant species in mangrove ecosystems of Pattani Bay, Thailand.

    PubMed

    Kaewtubtim, Pungtip; Meeinkuirt, Weeradej; Seepom, Sumalee; Pichtel, John

    2017-02-15

    Little is known regarding phytoremediation of radionuclides from soil; even less is known about radionuclide contamination and removal in tropical ecosystems such as mangrove forests. In mangrove forests in Pattani Bay, Thailand, 18 plant species from 17 genera were evaluated for radionuclide concentrations within selected plant parts. Two shrub species, Avicennia marina and Pluchea indica, accumulated the highest (232)Th (24.6Bqkg(-1)) and (40)K (220.7Bqkg(-1)) activity concentrations in roots, respectively. Furthermore, the aquatic species Typha angustifolia accumulated highest (232)Th, (40)K and (226)Ra activity concentrations (85.2, 363.5, 16.6Bqkg(-1), respectively) with the highest transfer factors (TFs) (3.0, 2.0, 5.9, respectively) in leaves. Leaves of T. angustifolia had an absorbed dose rate in air (D) over the recommended value (74.8nGyh(-1)) that was considered sufficiently high to be of concern for human consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Vertical migration of 60Co, 137Cs and 226Ra in agricultural soils as observed in lysimeters under crop rotation.

    PubMed

    Shinonaga, T; Schimmack, W; Gerzabek, M H

    2005-01-01

    In most studies quantifying the migration parameters - apparent migration velocity and apparent dispersion coefficient - of radionuclides in the soil by model calculations, these parameters are determined for undisturbed soils. For soils disturbed by ploughing, however, no such data are available in the literature. Therefore, in the present study, the migration parameters of (137)Cs, (60)Co and (226)Ra were estimated for ploughed soils by means of a convection-dispersion model. The depth distributions of the radionuclides were determined in four lysimeters (area: 1m(2), depth of soil monolith: 0.75m) filled with artificially contaminated soils of different types in July 1990. The lysimeters were cropped with agricultural plants. The soil in each lysimeter was ploughed manually once a year until 1996 (plough depth 20cm). In July 1999, soil samples were collected from three pits in each lysimeter. The depth distributions of all radionuclides proved to be very similar in each soil pit. The spatial variability of the depth distributions of a given radionuclide within the lysimeters was about the same as their variability between the four lysimeters. Evaluation of the migration parameters revealed that the convective transport of the radionuclides was always rather small or even zero, while the dispersive transport caused a "melting" process of the initially sharp activity edge at the lower border of the Ap horizon. These results are explained by the high evapotranspiration (80-90% of the total precipitation plus irrigation) and the small amounts of seepage water during the observation period of 9 years.

  19. Natural radioactivity (226Ra, 232Th and 40K) and assessment of radiological hazards in the Kestanbol granitoid, Turkey.

    PubMed

    Canbaz, Buket; Cam, N Füsun; Yaprak, Günseli; Candan, Osman

    2010-09-01

    The surveys of natural gamma-emitting radionuclides in rocks and soils from the Ezine plutonic area were conducted during 2007. Direct dose measurement using a survey meter was carried out simultaneously. The present study, which is part of the survey, analysed the activity concentrations of (238)U, (232)Th and (40)K in granitoid samples from all over the region by HPGe gamma spectrometry. The activity concentrations of (226)Ra ranged from 94 to 637 Bq kg(-1), those of (232)Th ranged from 120 to 601 Bq kg(-1)and those of (40)K ranged from 1074 to 1527 Bq kg(-1) in the analysed rock samples from different parts of the pluton. To evaluate the radiological hazard of the natural radioactivity in the samples, the absorbed dose rate (D), the annual effective dose rate, the radium equivalent activity (Ra(eq)) and the external (H(ex)) hazard index were calculated according to the UNSCEAR 2000 report. The thorium-to-uranium concentration ratios were also estimated.

  20. Laser-trapping of {sup 225}Ra and {sup 226}Ra with repumping by room-temperature blackbody radiation.

    SciTech Connect

    Guest, J. R.; Scielzo, N. D.; Ahmad, I.; Bailey, K.; Greene, J. P.; Holt, R. J.; Lu, Z.-T.; O'Connor, T. P.; Potterveld, D. H.; Physics; Enrico Fermi Inst.; Univ. of Chicago

    2007-02-27

    We have demonstrated Zeeman slowing and capture of neutral {sup 225}Ra and {sup 226}Ra atoms in a magneto-optical trap. The intercombination transition {sup 1}S{sub 0} {yields} {sup 3}P{sub 1} is the only quasicycling transition in radium and was used for laser-cooling and trapping. Repumping along the {sup 3}D{sub 1} {yields} {sup 1}P{sub 1} transition extended the lifetime of the trap from milliseconds to seconds. Room-temperature blackbody radiation was demonstrated to provide repumping from the metastable {sup 3}P{sub 0} level. We measured the isotope shift and hyperfine splittings on the {sup 3}D{sub 1} {yields} {sup 1}P{sub 1} transition with the laser-cooled atoms, and set a limit on the lifetime of the {sup 3}D{sub 1} level based on the measured blackbody repumping rate. Laser-cooled and trapped radium is an attractive system for studying fundamental symmetries.

  1. Laser Trapping of {sup 225}Ra and {sup 226}Ra with Repumping by Room-Temperature Blackbody Radiation

    SciTech Connect

    Guest, J. R.; Scielzo, N. D.; Ahmad, I.; Bailey, K.; Greene, J. P.; Holt, R. J.; O'Connor, T. P.; Potterveld, D. H.; Lu, Z.-T.

    2007-03-02

    We have demonstrated Zeeman slowing and capture of neutral {sup 225}Ra and {sup 226}Ra atoms in a magneto-optical trap. The intercombination transition {sup 1}S{sub 0}{yields}{sup 3}P{sub 1} is the only quasicycling transition in radium and was used for laser-cooling and trapping. Repumping along the {sup 3}D{sub 1}{yields}{sup 1}P{sub 1} transition extended the lifetime of the trap from milliseconds to seconds. Room-temperature blackbody radiation was demonstrated to provide repumping from the metastable {sup 3}P{sub 0} level. We measured the isotope shift and hyperfine splittings on the {sup 3}D{sub 1}{yields}{sup 1}P{sub 1} transition with the laser-cooled atoms, and set a limit on the lifetime of the {sup 3}D{sub 1} level based on the measured blackbody repumping rate. Laser-cooled and trapped radium is an attractive system for studying fundamental symmetries.

  2. Mobile gamma-ray scanning system for detecting radiation anomalies associated with /sup 226/Ra-bearing materials

    SciTech Connect

    Myrick, T.E.; Blair, M.S.; Doane, R.W.; Goldsmith, W.A.

    1982-11-01

    A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the Department of Energy's remedial action survey programs. The unit consists of a NaI(T1) detection system housed in a specially-equipped van. The system is operator controlled through an on-board mini-computer, with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided by a floppy disk system. Multichannel analysis capabilities are included for qualitative radionuclide identification. A /sup 226/Ra-specific algorithm is employed to identify locations containing residual radium-bearing materials. This report presents the details of the system description, software development, and scanning methods utilized with the ORNL system. Laboratory calibration and field testing have established the system sensitivity, field of view, and other performance characteristics, the results of which are also presented. Documentation of the instrumentation and computer programs are included.

  3. About the assumption of linearity in soil-to-plant transfer factors for uranium and thorium isotopes and 226Ra.

    PubMed

    Blanco, Rodríguez P; Vera, Tomé F; Lozano, J C

    2002-02-04

    The linearity assumption for soil and plant concentrations of radionuclides is usually a good approximation for use in food-chain models. To verify this assumption, different samples of plant and substrate were collected from a granitic zone located near a disused uranium mine in order to cover a large range of concentrations. In all of the samples, the activity concentration of 226Ra and of different isotopes of uranium (238U and 234U) and thorium (232Th, 230Th and 228Th) were determined. The results indicate that the linearity assumption can be considered valid when the range of concentrations taken into account is large (approx. two orders of magnitude). Otherwise, there is a clear deviation from linearity. Also, the influence of different stable elements on the soil-plant transfer factors was studied by using multivariate regression methods. The uptake of uranium, thorium and radium was found to be mainly associated with the concentration of iron in the plant and the phosphorus and alkaline earths in the substrate.

  4. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    NASA Astrophysics Data System (ADS)

    Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

    2012-03-01

    Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr-1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr-1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth

  5. [The determination of {sup 222}Rn flux from soils based on {sup 210}Pb and {sup 226}Ra disequilibrium]. Progress report

    SciTech Connect

    Turekian, K.K.

    1991-12-31

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  6. 226Ra, 232Th and 40K contents in water samples in part of central deserts in Iran and their potential radiological risk to human population

    PubMed Central

    2014-01-01

    Background The radiological quality of 226Ra, 232Th and 40K in some samples of water resources collected in Anarak-Khour a desertic area, Iran has been measured by direct gamma ray spectroscopy using high purity germanium detector in this paper. Result The concentration ranged from ≤0.5 to 9701 mBq/L for 226Ra; ≤0.2 to 28215 mBq/L for 232Th and < MDA to 10332 mBq/L for 40K. The radium equivalent activity was well below the defined limit of 370Bq/L. The calculated external hazard indices were found to be less than 1 which shows a low dose. Conclusion These results can be contributed to the database of this area because it may be used as disposal sites of nuclear waste in future. PMID:24883192

  7. Migration of the FDNPP-derived (134)Cs and (137)Cs along with (226)Ra and (228)Ra concentrations across the northwestern North Pacific Ocean.

    PubMed

    Inoue, M; Shirotani, Y; Nagao, S; Kofuji, H; Volkov, Y N; Nishioka, J

    2016-10-01

    We examined lateral distributions of (134)Cs, (137)Cs, (226)Ra, and (228)Ra in the surface seawaters around the Kuril Islands and the Kamchatka Peninsula in the northwestern North Pacific Ocean during June 2014. The sampling area included three water current areas, the Oyashio Current, the current from the Okhotsk Sea, and the coastal current along the east Kamchatka Peninsula. (226)Ra and (228)Ra distributions differed along the three currents. Low levels of (134)Cs were detected in the surface waters of the Oyashio Current (0.09-0.35 mBq/L), but it was <∼0.1 mBq/L at the surface along the other two currents. This indicates that the distribution of Fukushima Dai-ichi Nuclear Power Plant (FDNPP)-derived radiocesium in surface waters off the Kamchatka and along the Kuril Islands is predominantly governed by the Oyashio current system.

  8. Radium isotope ((223)Ra, (224)Ra, (226)Ra and (228)Ra) distribution near Brazil's largest port, Paranaguá Bay, Brazil.

    PubMed

    Dias, Thais H; de Oliveira, Joselene; Sanders, Christian J; Carvalho, Franciane; Sanders, Luciana M; Machado, Eunice C; Sá, Fabian

    2016-10-15

    This work investigates the (223)Ra, (224)Ra, (226)Ra and (228)Ra isotope distribution in river, estuarine waters and sediments of the Paranaguá Estuarine Complex (PEC). The stratification of the Ra isotopes along water columns indicate differing natural sources. In sediments, the radium isotope activities was inversely proportional to the particle size. The highest concentrations of (223)Ra, (224)Ra, (226)Ra and (228)Ra in the water column were found in the bottom more saline waters and towards the inner of the estuary. These relatively high concentrations towards the bottom of the estuary may be attributed to the influence of tidally driven groundwater source and desorption from particles at the maximum turbidity zone. The apparent river water ages from the radium isotope ratios, (223)Ra/(224)Ra and (223)Ra/(228)Ra, indicate that the principal rivers that flow into the estuary have residence times from between 6 and 11days. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Tracking suspended particle transport via radium isotopes ((226)Ra and (228)Ra) through the Apalachicola-Chattahoochee-Flint River system.

    PubMed

    Peterson, Richard N; Burnett, William C; Opsahl, Stephen P; Santos, Isaac R; Misra, Sambuddha; Froelich, Philip N

    2013-02-01

    Suspended particles in rivers can carry metals, nutrients, and pollutants downstream which can become bioactive in estuaries and coastal marine waters. In river systems with multiple sources of both suspended particles and contamination sources, it is important to assess the hydrologic conditions under which contaminated particles can be delivered to downstream ecosystems. The Apalachicola-Chattahoochee-Flint (ACF) River system in the southeastern United States represents an ideal system to study these hydrologic impacts on particle transport through a heavily-impacted river (the Chattahoochee River) and one much less impacted by anthropogenic activities (the Flint River). We demonstrate here the utility of natural radioisotopes as tracers of suspended particles through the ACF system, where particles contaminated with arsenic (As) and antimony (Sb) have been shown to be contributed from coal-fired power plants along the Chattahoochee River, and have elevated concentrations in the surficial sediments of the Apalachicola Bay Delta. Radium isotopes ((228)Ra and (226)Ra) on suspended particles should vary throughout the different geologic provinces of this river system, allowing differentiation of the relative contributions of the Chattahoochee and Flint Rivers to the suspended load delivered to Lake Seminole, the Apalachicola River, and ultimately to Apalachicola Bay. We also use various geochemical proxies ((40)K, organic carbon, and calcium) to assess the relative composition of suspended particles (lithogenic, organic, and carbonate fractions, respectively) under a range of hydrologic conditions. During low (base) flow conditions, the Flint River contributed 70% of the suspended particle load to both the Apalachicola River and the bay, whereas the Chattahoochee River became the dominant source during higher discharge, contributing 80% of the suspended load to the Apalachicola River and 62% of the particles entering the estuary. Neither of these hydrologic

  10. Mapping the spatial distribution and activity of (226)Ra at legacy sites through Machine Learning interpretation of gamma-ray spectrometry data.

    PubMed

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul; Davies, Mike

    2016-03-01

    Radium ((226)Ra) contamination derived from military, industrial, and pharmaceutical products can be found at a number of historical sites across the world posing a risk to human health. The analysis of spectral data derived using gamma-ray spectrometry can offer a powerful tool to rapidly estimate and map the activity, depth, and lateral distribution of (226)Ra contamination covering an extensive area. Subsequently, reliable risk assessments can be developed for individual sites in a fraction of the timeframe compared to traditional labour-intensive sampling techniques: for example soil coring. However, local heterogeneity of the natural background, statistical counting uncertainty, and non-linear source response are confounding problems associated with gamma-ray spectral analysis. This is particularly challenging, when attempting to deal with enhanced concentrations of a naturally occurring radionuclide such as (226)Ra. As a result, conventional surveys tend to attribute the highest activities to the largest total signal received by a detector (Gross counts): an assumption that tends to neglect higher activities at depth. To overcome these limitations, a methodology was developed making use of Monte Carlo simulations, Principal Component Analysis and Machine Learning based algorithms to derive depth and activity estimates for (226)Ra contamination. The approach was applied on spectra taken using two gamma-ray detectors (Lanthanum Bromide and Sodium Iodide), with the aim of identifying an optimised combination of detector and spectral processing routine. It was confirmed that, through a combination of Neural Networks and Lanthanum Bromide, the most accurate depth and activity estimates could be found. The advantage of the method was demonstrated by mapping depth and activity estimates at a case study site in Scotland. There the method identified significantly higher activity (<3 Bq g(-1)) occurring at depth (>0.4m), that conventional gross counting algorithms

  11. Extensive radioactive characterization of a phosphogypsum stack in SW Spain: 226Ra, 238U, 210Po concentrations and 222Rn exhalation rate.

    PubMed

    Abril, José-María; García-Tenorio, Rafael; Manjón, Guillermo

    2009-05-30

    Phosphogypsum (PG) is a by-product of the phosphate fertilizer industries that contains relatively high concentrations of uranium series radionuclides. The US-EPA regulates the agriculture use of PG, attending to its (226)Ra content and to the (222)Rn exhalation rate from inactive stacks. Measurements of (222)Rn exhalation rates in PG stacks typically show a large and still poorly understood spatial and temporal variability, and the published data are scarce. This work studies an inactive PG stack in SW Spain of about 0.5 km(2) from where PG can be extracted for agriculture uses, and an agriculture soil 75 km apart, being representative of the farms to be amended with PG. Activity concentrations of (226)Ra, (238)U and (210)Po have been measured in 30 PG samples (0-90 cm horizon) allowing for the construction of maps with spatial distributions in the PG stack and for the characterization of the associated PG inputs to agriculture soils. Averaged (226)Ra concentrations for the stack were 730+/-60 Bq kg(-1) (d.w.), over the US-EPA limit of 370 Bq kg(-1). (222)Rn exhalation rate has been measured by the charcoal canister method in 49 sampling points with 3 canisters per sampling point. Values in PG stack were under the US-EPA limit of 2600 Bq m(-2)h(-1), but they were one order of magnitude higher than those found in the agriculture soil. Variability in radon emissions has been studied at different spatial scales. Radon exhalation rates were correlated with (226)Ra concentrations and daily potential evapotranspiration (ETo). They increased with ETo in agriculture soils, but showed an opposite behaviour in the PG stack.

  12. The cumulative effect of three decades of phosphogypsum amendments in reclaimed marsh soils from SW Spain: (226)Ra, (238)U and Cd contents in soils and tomato fruit.

    PubMed

    Abril, José-María; García-Tenorio, Rafael; Enamorado, Santiago M; Hurtado, M Dolores; Andreu, Luis; Delgado, Antonio

    2008-09-15

    Phosphogypsum (PG), a by-product of the phosphate fertiliser industries, has been applied as soil amendment to reduce Na saturation in soils, as in the reclaimed marsh area from SW Spain, where available PG has a typical fingerprint of 710+/-40 Bq kg(-1) of (226)Ra, 165+/-15 Bq kg(-1) of (238)U and 2.8+/-0.4 mg kg(-1) of Cd. This work was focussed on the cumulative effects of PG amendments on the enrichment of these pollutants in cultivated soils and plants (Lycopersicum esculentum Mill L.) from the area studied, where PG has been applied since 1978 at recommended rates of 20-25 Mg ha(-1) every 2-3 years. A field experiment was conducted over three years to compare activity concentrations of (226)Ra ((214)Pb) and (238)U ((234)Th) in non-reclaimed soils, reclaimed soils with no additional PG application, and reclaimed soils with two additional PG applications. A non-significant effect of two PG amendments (in three years) was observed when compared with non-amended reclaimed plots. Nevertheless, a significant (p<0.05) enrichment of (226)Ra was observed in the surface horizon (0-30 cm) of reclaimed plots relative to deeper horizons and also when compared with the surface horizon of non-reclaimed soil (p<0.05), thereby revealing the cumulative effect of three decades of PG applications. Furthermore, the effect of a continuous application of PG was studied by analysing soils and tomato fruits from six commercial farms with different cumulative rates of PG applied. Cadmium concentrations in tomatoes, which were one order of magnitude higher than those found in tomatoes from other areas in South Spain, were positively correlated (r = 0.917) with (226)Ra-concentration in soils, which can be considered an accurate index of the cumulative PG rate of each farm.

  13. STUDY OF NATURAL RADIOACTIVITY (226Ra, 232Th AND 40K) IN SOIL SAMPLES FOR THE ASSESSMENT OF AVERAGE EFFECTIVE DOSE AND RADIATION HAZARDS.

    PubMed

    Bangotra, Pargin; Mehra, Rohit; Kaur, Kirandeep; Jakhu, Rajan

    2016-10-01

    The activity concentration of (226)Ra (radium), (232)Th (thorium) and (40)K (potassium) has been measured in the soil samples collected from Mansa and Muktsar districts of Punjab (India) using NaI (Tikl) gamma detector. The concentration of three radionuclides ((226)Ra, (232)Th and (40)K) in the studied area has been varied from 18±4 to 46±5, 53±7 to 98±8 and 248±54 to 756±110 Bq kg(-1), respectively. Radium equivalent activities (Raeq) have been calculated in soil samples for the assessment of the radiation hazards arising due to the use of these soil samples. The absorbed dose rate of (226)Ra, (232)Th and (40)K in studied area has been varied from 8 to 21, 33 to 61 and 9 to 25 nGy h(-1), respectively. The corresponding indoor and outdoor annual effective dose in studied area was 0.38 and 0.09 mSv, respectively. The external and internal hazard has been also calculated for the assessment of radiation hazards in the studied area.

  14. 226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings near Elliot Lake, Canada.

    PubMed

    Clulow, F V; Mirka, M A; Davé, N K; Lim, T P

    1991-01-01

    Radionuclide levels were measured in tissues, gut contents, diet items, and water at site of capture, of adult beavers from the Serpent River drainage basin which contains U tailings at Elliot Lake, Ontario, and from nearby control sites. Levels of (226)Ra in beaver bone, muscle and kidney were highest in animals from locations close to U tailings; liver levels did not vary by site. Environmental (226)Ra levels were within ranges previously reported at these or similar locations elsewhere; levels in beaver gut contents reflected levels in diet items. Concentration ratios exceeded unity only between some vegetation items and beaver bone at the Elliot Lake site and were less than 0.19 between vegetation and other tissues. In two beavers with tissue levels of (226)Ra higher than other sampled, neither (232)Th nor (230)Th were detected in bone, muscle or liver tissues. U-238 was measurable in bone, muscle and liver, (228)Th in bone, (210)Po bone, muscle and liver; and (210)Pb was measurable only in bone. Estimated yearly intakes of radionuclides by people eating beavers were calculated to be below current allowable levels set by the Canadian regulatory authorities.

  15. An efficient and simple method for measuring (226)Ra using the scintillation cell in a delayed coincidence counting system (RaDeCC).

    PubMed

    Waska, Hannelore; Kim, Seolwon; Kim, Guebuem; Peterson, Richard N; Burnett, William C

    2008-12-01

    A delayed coincidence counter (RaDeCC), developed to determine ultra-low levels of (223)Ra (half life = 11.1 days) and (224)Ra (half life = 3.6 days) in seawater, was adapted to measure (226)Ra (half life = 1622 years). After pre-concentration of Ra from seawater onto MnO(2)-coated fiber we show in this study that the (226)Ra activity can be determined using the RaDeCC's ability to record alpha decay of its daughters as total counts. For sufficient ingrowth of (222)Rn, the Mn-fiber is hermetically sealed in a column for a few days. Then, the ingrown (222)Rn is circulated through the RaDeCC air-loop system followed by shutting down of the pump and closure of the scintillation cell for equilibration. Counting may be completed within a few hours for seawater samples. Sample measurements with this method agreed well with data obtained using gamma-ray spectrometry. This proves that a set of Ra isotopes ((223)Ra, (224)Ra, and (226)Ra), commonly used for geophysical studies such as mixing rates of different water masses and submarine groundwater discharge, can be efficiently and rapidly measured using the RaDeCC.

  16. Annual intakes of (226)Ra, (228)Ra and (40)K in staple foodstuffs from a high background radiation area in the southwest region of Cameroon.

    PubMed

    Ele Abiama, P; Ben-Bolie, G H; Amechmachi, N; Najib, F; El Khoukhi, T; Owono Ateba, P

    2012-08-01

    Concentrations of naturally occurring radionuclides (226)Ra, (228)Ra and (40)K were determined in five most consumed vegetables in a high-level background radiation area (HLBRA) in the southwest region of Cameroon. A total of 25 foodstuff samples collected from Akongo, Ngombas, Awanda, Bikoué and Lolodorf rural districts were analyzed by gamma spectrometry. The average activity concentration values of (226)Ra, (228)Ra and (40)K were respectively 2.30, 1.50 and 140.40 Bq kg(-1) fresh-weights. The effective dose for individual consumption of the investigated foodstuff types was calculated on an estimated annual intake of such diets in the study area. The estimated total daily effective doses from the ingestion of the investigated foodstuffs for each studied long-life natural radionuclide were respectively 0.41 μSv for (226)Ra, 0.84 μSv for (228)Ra and 0.71 μSv for (40)K. The total annual effective dose was estimated at 0.70 mSv y(-1). (228)Ra (44%) and (40)K (36%) were found to be the main sources for internal irradiation which is very likely due to the specific uptake of these radionuclides by the studied plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Analysis of the distribution characteristics of 226Ra and 228Ra and their sources in the western part of Qinghai Lake

    NASA Astrophysics Data System (ADS)

    Kong, Fancui; Sha, Zhanjiang; Du, Jinzhou; Su, Weigang; Yu, Chenguang; Zhao, Shunli; Hu, Jufang; Ye, Mei

    2015-11-01

    The 226Ra and 228Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of 226Ra and 228Ra were discussed according to their distribution characteristics. 226Ra and 228Ra activities (dpm/(100 L)) ranged from 14.13±0.22 to 19.22±0.42 and 17.72±0.66 to 30.96±1.47 in the surface water of the North Bay, respectively, and from 7.88±0.24 to 33.80±0.47 and 15.73±0.74 to 57.31±1.44, respectively, in the South Bay. The surface water near the estuary had a lower salinity and had a higher concentration of radium isotopes than the samples collected further away. The farther offshore the sample, the higher the salinity was, and the lower the radium isotope activity. The distribution of radium activities in the western part of Qinghai Lake is controlled by several factors, including Buha River runoff, desorption from suspended particles derived from the river, groundwater discharge, and a small amount of diffusion from the sediment.

  18. Measurement of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs in foodstuffs samples collected from coastal areas of China.

    PubMed

    Tuo, Fei; Zhang, Qing; Zhou, Qiang; Xu, Cuihua; Zhang, Jing; Li, Wenhong; Zhang, Jianfeng; Su, Xu

    2016-05-01

    This study represents a total of 245 samples collected. The activities of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs were determined in samples of vegetables, tea, cereal (rice, wheat and corn), meat, poultry, freshwater product, seafood and seaweed that collected from the 30km safety zone of the Nuclear Power Plants (NPPs) area. All the samples radionuclide activities were quantified by using High Purity Germanium (HPGe) gamma spectrometry. The geometric mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.13, 0.16, 0.11, 68 and 0.02, respectively. The arithmetic mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.34, 0.65, 0.32, 111 and 0.09, respectively. Results of this study were compared with others, the measured values are the same with those of a previous investigation. Radiation doses due to the consumption of these foodstuffs to humans are estimated to comprise around 37-46% of the annual dose limit for public. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Investigations on the activity concentrations of 238U, 226RA, 228RA, 210PB and 40K in Jordan phosphogypsum and fertilizers.

    PubMed

    Al-Jundi, J; Al-Ahmad, N; Shehadeh, H; Afaneh, F; Maghrabi, M; Gerstmann, U; Höllriegl, V; Oeh, U

    2008-01-01

    The activity concentrations of naturally occurring radionuclides ((238)U, (226)Ra, (228)Ra, (210)Pb and (40)K) in Jordanian phosphate ore, fertilizer material and phosphogypsum piles were investigated. The results show the partitioning of radionuclides in fertilizer products and phosphogypsum piles. The outcome of this study will enrich the Jordanian radiological map database, and will be useful for an estimation of the radiological impact of this industrial complex on the immediate environment. The activity concentration of (210)Pb was found to vary from 95 +/- 8 to 129 +/- 8 Bq kg(-1) with a mean value of 111 +/- 14 Bq kg(-1) in fertilizer samples, and from 364 +/- 8 to 428 +/- 10 Bq kg(-1) with a mean value of 391 +/- 30 Bq kg(-1) in phosphogypsum samples; while in phosphate wet rock samples, it was found to vary between 621 +/- 9 and 637 +/- 10 Bq kg(-1), with a mean value of 628 +/- 7 Bq kg(-1). The activity concentration of (226)Ra in fertilizer samples (between 31 +/- 4 and 42 +/- 5 Bq kg(-1) with a mean value of 37 +/- 6 Bq kg(-1)) was found to be much smaller than the activity concentration of (226)Ra in phosphogypsum samples (between 302 +/- 8 and 442 +/- 8 Bq kg(-1) with a mean value of 376 +/- 62 Bq kg(-1)). In contrast, the activity concentration of (238)U in fertilizer samples (between 1011 +/- 13 and 1061 +/- 14 Bq kg(-1) with a mean value of 1033 +/- 22 Bq kg(-1)) was found to be much higher than the activity concentration of (238)U in phosphogypsum samples (between 14 +/- 5 and 37 +/- 7 Bq kg(-1) with a mean value of 22 +/- 11 Bq kg(-1)). This indicates that (210)Pb and (226)Ra show similar behaviour, and are concentrated in phosphogypsum piles. In addition, both isotopes enhanced the activity concentration in phosphogypsum piles, while (238)U enhanced the activity concentration in the fertilizer. Due to the radioactivity released from the phosphate rock processing plants into the environment, the highest collective dose commitment for the lungs

  20. Activity concentration, transfer factors and resultant radiological risk of 226Ra, 232Th, and 40K in soil and some vegetables consumed in Selangor, Malaysia

    NASA Astrophysics Data System (ADS)

    Solehah, A. R.; Yasir, M. S.; Samat, S. B.

    2016-11-01

    The activity concentrations of the natural radionuclides 226Ra, 232Th, and 40K were determined in vegetable crops consumed by Malaysian people in Sungai Besar, Selangor. Sample of vegetables and the soil where the crops were cultivated and collected at five different location. The activity concentrations in Bq/kg of 226Ra, 232Th, and 40K were measured by the gamma-ray spectroscopy using the high purity germanium detector. The range activity concentration in soil is between 51.81 and 71.84 Bq/kg, 64.18 and 78.00 Bq/kg, and 210.49 and 244.29 Bq/kg for 226Ra, 232Th, and 40K, respectively. The activity concentration of 226Ra, 232Th, and 40K in vegetables were found to be in the range of 2.06 to 5.44 Bq/kg, Not Detectable to 0.61 Bq/kg, and 101.00 to 1223.09 Bq/kg, respectively. The activity concentration in both soil and vegetables were all less than lower limit stated by UNSCEAR. The Transfer Factors range value for 226Ra, 232Th, and 40K varied from 0.02 to 0.06, 0.003 to 0.008, and 1.79 to 5.19 respectively. Radium equivalent for soil range from 165.57 to 194.84 Bq/kg. It was within the international accepted value (370 Bq/kg). Absorb dose rate for soil range between 73.5 to 86.40 nGyh-1, in safe range from limit of international accepted value (55nGyh-1). Effective dose rate is found to be in range of 0.09 to 0.11 mSvy-1 for soil which is less than 2.4 mSv/y. External and Internal Hazard indices of soil was all below 1, within agreement of other researcher and UNSCEAR. The estimation of the consequent radiological risk due to the presence of those radionuclides is significantly low.

  1. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    NASA Astrophysics Data System (ADS)

    Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

    2011-12-01

    Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of corals from one of the world's largest known cold-water coral reef, the Røst Reef off Norway. Two large branching framework-forming cold-water coral specimens, one Lophelia pertusa and one Madrepora oculata were collected alive at 350 m water depth from the Røst Reef at ~67° N and ~9° E. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and the corals trace element compositions were studied using ICP-QMS. Due to the different chemical behaviors of Pb and Ra in the marine environment, 210Pb and 226Ra were not incorporated the same way into the aragonite skeleton of those two cold-water corals. Thus to assess of the growth rates of both specimens we have here taken in consideration the exponential decrease of initially incorporated 210Pb as well as the ingrowth of 210Pb from the decay of 226Ra. Moreover a~post-depositional 210Pb incorporation is found in relation to the Mn-Fe coatings that could not be entirely removed from the oldest parts of the skeletons. The 226Ra activities in both corals were fairly constant, then assuming constant uptake of 210Pb through time the 210Pb-226Ra chronology can be applied to calculate linear growth rate. The 45.5 cm long branch of M. oculata reveals an age of 31 yr and a~linear growth rate of 14.4 ± 1.1 mm yr-1, i.e. 2.6 polyps per year. However, a correction regarding a remaining post-depositional Mn-Fe oxide coating is needed for the base of the specimen. The corrected age tend to confirm the radiocarbon derived basal age of 40 yr (using 14C bomb peak) with a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in Aquaria experiments under optimal growth conditions. For the 80 cm-long specimen of L. pertusa a remaining contamination of metal-oxides is observed for the middle and basal part of the coral skeleton, inhibiting similar accurate age

  2. Radon concentration in soil gas and its correlations with pedologies, permeabilities and 226Ra content in the soil of the Metropolitan Region of Belo Horizonte - RMBH, Brazil

    NASA Astrophysics Data System (ADS)

    Lara, E.; Rocha, Z.; Palmieri, H. E. L.; Santos, T. O.; Rios, F. J.; Oliveira, A. H.

    2015-11-01

    The radon concentration in soil gas is directly dependent on the geological characteristics of the area, such as lithology, pedology and on geochemicals, physicals and mineralogicals parameters of the soil. This paper looks for correlations between radon concentrations in soil gas and its soil permeability, 238U, 232Th and 226Ra contents in the soil groups classified by pedologies of Metropolitan Region of Belo Horizonte (RMBH), Minas Gerais, Brazil. The soil gas radon concentrations were determined by using an AlphaGUARD® monitor at about 150 measurement points. In soil samples of the same measurement points, the concentrations of 226Ra were determined by gamma spectrometry (HPGe), and 238U and 232Th by ICP-MS. The soil permeabilities were determined by using the RADON-JOK® permeameter. The mean concentrations of radon in soil gas ranged from 13.6±3.0 kBq m-3 for Litholic Neosols until 60.6±8.7 kBq m-3 for Perferric Red Latosols. The mean of 226Ra activity concentrations presented variation of 12.4±2.5 Bq kg-1 for Litholic Neosols until 50.3±13 Bq kg-1 for Perferric Red Latosols. Approximately 40% of the soils presented high permeability. The areas of different pedologies were classified by Soil Radon Index (SRI), determined by the soil gas radon concentration and permeability. Approximately 53% of the Perferric Red Latosols measurement site could be classified as "High Risk" (Swedish criteria). The preliminary results may indicate an influence of iron formations present very close to the Perferric Red Latosols in the retention of uranium minerals, and hence an increase in the concentration of radon and radium, whereas the series are in equilibrium in the environment.

  3. Quantification of transfer of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses of a semi-natural ecosystem.

    PubMed

    Dragović, S; Mihailović, N; Gajić, B

    2010-02-01

    There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.

  4. Study on the radioactivity and soil-to-plant transfer factor of (226)Ra, (234)U and (238)U radionuclides in irrigated farms from the northwestern Saudi Arabia.

    PubMed

    Al-Hamarneh, Ibrahim F; Alkhomashi, N; Almasoud, Fahad I

    2016-08-01

    The present study addresses the soil-to-plant transfer factors (TFs) of (226)Ra, (234)U and (238)U for 13 types of vegetables and agricultural crops planted under semi-arid environment in the northwestern part of Saudi Arabia. Crop plants along with plant-growing soils were collected from selected farms, which are irrigated from the non-renewable Saq aquifer, and investigated for their radioactivity content by means of alpha spectrometry after applying a radiochemical separation procedure. Hence, TF data for plant roots, green parts (stem and leaves) and fruits were calculated and contrasted to those reported in the literature. Substantial differences were observed in the TFs of Ra and U radioisotopes among plant species. In crop fruits, eggplant exhibited the highest uptake of (226)Ra (TF value of 0.11), while beans (0.16) have the highest TF for (234)U and (238)U. The geometric mean TF values indicated that the crop roots tend to accumulate Ra and U about four to six-folds higher than fruits. The relation between TF values and soil concentrations showed a weak correlation. Activity ratios between radionuclides in crop plants indicated the preferential translocation of U in fruits than Ra even though Ra is more available for root uptake. The fruit/root (F/R) ratios obtained for the investigated plants shown that pepper had the smallest F/R ratios (0.07 ± 0.01, 0.12 ± 0.02 and 0.11 ± 0.02 for (226)Ra, (234)U and (238)U, respectively), while the highest F/R ratios were observed in potatoes (0.71 ± 0.15, 0.44 ± 0.10 and 0.40 ± 0.08 for (226)Ra, (234)U and (238)U, respectively). The TF and F/R ratios data of natural radionuclides in the study region can hopefully improve the scientific knowledge for future studies.

  5. (226)Ra measurement by LSC as a tool to assess the efficiency of a water treatment technology for removing radionuclides from groundwater.

    PubMed

    Suursoo, Siiri; Kiisk, Madis; Al-Malahmeh, Amer; Jantsikene, Alar; Putk, Kaisa; Lumiste, Liie

    2014-11-01

    A simple (226)Ra analysis procedure by LSC with an extractive scintillator was tested for evaluating the long-term radionuclides removal efficiency of a water treatment facility at Viimsi, Estonia. During the 14 months of operation, total radium removal efficiency of the treatment process has stayed over 90%, but the removal efficiencies of the different purification steps have varied notably. This demonstrates the need for routine monitoring of radium content in the water treatment plant. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. NIST 222Rn emission standards.

    PubMed

    Volkovitsky, Peter

    2006-01-01

    NIST radon standards are hermetically sealed polyethylene capsules filled with 226Ra solution. Recently, four new series of standards with activities 5, 50, 500, and 5000 Bq were prepared. The measured emanation fraction agrees with a calculation that accounts for the radon accumulated inside the polyethylene walls of the capsule. Obtained solubility of radon in polyethylene is approximately 45 of the solubility of radon in water. The radon diffusion coefficient in low-density polyethylene is 7.2x10(-8)cm2/s.

  7. High sensitivity measurement of 224Ra and 226Ra in water with an improved hydrous titanium oxide technique at the Sudbury Neutrino Observatory

    NASA Astrophysics Data System (ADS)

    Aharmim, B.; Cleveland, B. T.; Dai, X.; Doucas, G.; Farine, J.; Fergani, H.; Ford, R.; Hahn, R. L.; Hallman, E. D.; Jelley, N. A.; Lange, R.; Majerus, S.; Mifflin, C.; Noble, A. J.; O'Keeffe, H. M.; Rodriguez-Jimenez, R.; Sinclair, D.; Yeh, M.

    2009-06-01

    The existing hydrous titanium oxide (HTiO) technique for the measurement of 224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been changed to make it faster and less sensitive to trace impurities in the HTiO eluate. Using HTiO-loaded filters followed by cation exchange adsorption and HTiO co-precipitation, Ra isotopes from 200 to 450 tonnes of heavy water can be extracted and concentrated into a single sample of a few millilitres with a total chemical efficiency of 50%. Combined with beta-alpha coincidence counting, this method is capable of measuring 1.5×10-3 μBq/kg of 224Ra and 3.3×10-3 μBq/kg of 226Ra from the 232Th and 238U decay chains, respectively, for a 275 tonne D2O assay, which are equivalent to 4×10-16 g Th/g and 3×10-16 g U/g in heavy water.

  8. Assessment of (226)Ra, (238)U, (232)Th, (137)Cs and (40)K activities from the northern coastline of Oman Sea (water and sediments).

    PubMed

    Darabi-Golestan, F; Hezarkhani, A; Zare, M R

    2017-02-27

    Water and sediment samples were collected from northern coast of Oman Sea covering from Goatr to Hormoz canyon seaport. Water and sediment quality assessment for naturally or anthropogenic radionuclides at Oman Sea as a main strategic golf for trade and transit, is an important issue. Correspondence analysis (CA) by R-mode analysis represents that sigma(T)-temperature-conductivity-O2 parameters are well-correlated with (226)Ra, (232)Th and (40)K. Accordingly Q-mode analysis revealed an indicator samples of ST13W for different radionuclides, ST03W for O2, and simultaneously ST34W-ST21W-ST08W-ST04W for sigma(T) parameters. The CA results overlapped with factor and cluster analysis results that explained 85.8% of total variance of water samples. Descriptive analysis of sediments indicates more significant variation than water samples. The (232)Th and (226)Ra generally showing that ST13D to ST25D sediments that restricted to Pi Bashk coastline are concentrated from (137)Cs and (40)K. By comparison with reference-values from Iran and other parts of the world, they are acceptable with respect to environmental and radioisotope hazards.

  9. Assessment of environmental (226)Ra, (232)Th and (40)K concentrations in the region of elevated radiation background in Segamat District, Johor, Malaysia.

    PubMed

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Alajerami, Yasser; Aliyu, Abubakar Sadiq

    2013-10-01

    Extensive environmental survey and measurements of gamma radioactivity in the soil samples collected from Segamat District were conducted. Two gamma detectors were used for the measurements of background radiation in the area and the results were used in the computation of the mean external radiation dose rate and mean weighted dose rate, which are 276 nGy h(-1) and 1.169 mSv y(-1), respectively. A high purity germanium (HPGe) detector was used in the assessment of activity concentrations of (232)Th, (226)Ra and (40)K. The results of the gamma spectrometry range from 11 ± 1 to 1210 ± 41 Bq kg(-1) for (232)Th, 12 ± 1 to 968 ± 27 Bq kg(-1) for (226)Ra, and 12 ± 2 to 2450 ± 86 Bq kg(-1) for (40)K. Gross alpha and gross beta activity concentrations range from 170 ± 50 to 4360 ± 170 Bq kg(-1) and 70 ± 20 to 4690 ± 90 Bq kg(-1), respectively. These results were used in the plotting of digital maps (using ARCGIS 9.3) for isodose. The results are compared with values giving in UNSCEAR 2000.

  10. 238U-230Th-226Ra disequilibria in plagioclase from recent mixed magmas at Mount Hood: constraints on crystal storage timescales and eruption triggering processes

    NASA Astrophysics Data System (ADS)

    Eppich, G. R.; Cooper, K. M.; Kent, A. J.; Koleszar, A. M.

    2010-12-01

    Uranium-series crystal ages, interpreted within a textural and geochemical framework, can provide insight into crystal storage timescales and eruption triggering processes. Mount Hood is a mixing-driven volcano that consistently erupts magmas of intermediate composition. Mixed magmas incorporate plagioclase derived from mafic and silicic end-member magmas (Kent AJR; Darr C; Koleszar AM; Salisbury MJ; Cooper KM. 2010. Preferential eruption of andesitic magmas through recharge filtering. Nature Geosci.). We measured 238U-230Th-226Ra disequilibria for four plagioclase size fractions, groundmass separates, and mafic inclusions from the Timberline (1500 a) and Old Maid (215 a) eruptive sequences. Measured (230Th)/(238U) was 1.126-1.143 for Timberline plagioclase and 1.127-1.143 for Old Maid plagioclase. Measured (226Ra)/(230Th) was 1.22-1.62 for Timberline plagioclase and 1.27-1.43 for Old Maid plagioclase. Corrections were performed for the presence of groundmass in the >500 µm plagioclase separates, and large plagioclase + groundmass in the <500 µm plagioclase separates. Small (<500 µm) plagioclase, derived from mafic magma, records enriched present-day (226Ra)/Ba relative to equilibrium with liquid proxies (groundmass and mafic inclusions), leading to undefined Ra-Th model ages. However, the measured disequilibria require that the majority of plagioclase in the separate is young (<<10 ka). Large (>500 µm) plagioclase, derived from the silicic mixing end-member, records (238U)/(230Th) disequilibrium and minor (226Ra)/(230Th) disequilibrium. Ra-Th model ages are 5-10 ka. Rims of large plagioclase crystallized within weeks of eruption (Kent et al., 2010), suggesting that the 5-10 ka Ra-Th model ages are averages of young rim growth and old cores, which could be >10 ka. Crystallization timescales of large plagioclase cores are longer than timescales of repose between eruptions, suggesting that the crystals must have been present yet remained untapped during older

  11. Ground water contamination with (238)U, (234)U, (235)U, (226)Ra and (210)Pb from past uranium mining: cove wash, Arizona.

    PubMed

    Dias da Cunha, Kenya Moore; Henderson, Helenes; Thomson, Bruce M; Hecht, Adam A

    2014-06-01

    The objectives of the study are to present a critical review of the (238)U, (234)U, (235)U, (226)Ra and (210)Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing (238)U and (234)U. The water quality data were taken from Sect. "Data analysis" of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah-Navajo Lands 1994-2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410-1 Bq/L) in 19 % of the water samples, while (238)U and (234)U concentrations were above in 14 and 17 % of the water samples, respectively. (226)Ra and (210)Pb concentrations in water samples were in the range of 3.7 × 10(-1) to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the (226)Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the (210)Pb/(226)Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the (235)U/(total)U mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of (235)U to (total)U (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations

  12. Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra.

    PubMed

    Smith, Richard W; Seymour, Colin B; Mothersill, Carmel E

    2013-12-01

    Bystander effect induction by fathead minnows injected with environmentally relevant doses of (226)Ra was investigated. Twenty four h and 6 months after injection with a single dose of 21, 210 or 2100 μBq, fin tissue samples emitted a pro-apoptotic signal, which reduced the clonogenic survival of an apoptosis sensitive reporter cell line. Twenty four h and 10 weeks after injection explants from non-injected bystander fish, swum with the injected fish, also emitted a pro-apoptotic signal. However 6 months after injection the bystander fish to 21 and 210 μBq injected fish emitted an anti-apoptotic signal. This demonstrates that extremely low dose irradiation can have effects outside of the irradiated fish. This has implications for population and ecosystem responses to contamination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. An examination of groundwater discharge and the associated nutrient fluxes into the estuaries of eastern Hainan Island, China using 226Ra.

    PubMed

    Su, Ni; Du, Jinzhou; Moore, Willard S; Liu, Sumei; Zhang, Jing

    2011-09-01

    The nutrient concentrations and stoichiometry in a coastal bay/estuary are strongly influenced by the direct riverine discharge and the submarine groundwater discharge (SGD). To estimate the fluxes of submarine groundwater discharge into the Bamen Bay (BB) and the Wanquan River Estuary (WQ) of eastern Hainan Island, China, the naturally occurring radium isotope ((226)Ra) was measured in water samples collected in the bay/estuary in August 2007 and 2008. Based on the distribution of (226)Ra in the surface water, a 3-end-member mixing model was used to estimate the relative contributions of the sources to these systems. Flushing times of 3.9±2.7 and 12.9±9.3 days were estimated for the BB and WQ, respectively, to calculate the radium fluxes for each system. Based on the radium fluxes from groundwater discharge and the Ra isotopic compositions in the groundwater samples, the estimated SGD fluxes were 3.4±5.0 m(3) s(-1) in the BB and 0.08±0.08 m(3) s(-1) in the WQ, or 16% and 0.06%, respectively, of the local river discharge. Using this information, the nutrient fluxes from the submarine groundwater discharge seeping into the BB and WQ regions were estimated. In comparison with the nutrient fluxes from the local rivers, the SGD-derived nutrient fluxes played a vital role in controlling the nutrient budgets and stoichiometry in the study area, especially in the BB. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Distribution and possible dietary intake of radioactive 137Cs, 40K and 226Ra with the pantropical mushroom Macrocybe gigantea in SW China.

    PubMed

    Falandysz, Jerzy; Zhang, Ji; Zalewska, Tamara; Apanel, Anna; Wang, Yuanzhong; Wiejak, Anna

    2015-01-01

    There is scarcity of data on contamination with radiocesium 134/137Cs of edible mushrooms from the Southwestern Asia. This study aimed to get insight into activity concentration of artificial nuclides 134/137Cs and natural 40K and 226Ra in mushrooms from Yunnan province, which is major producer in China. The specimens of pantropical mushroom Macrocybe gigantea were collected from the wild and from a farm across Yunnan land in 2012-2013 and analyzed using gamma spectrometry with hyperpure germanium coaxial detector (HPGe). M. gigantea showed low activity concentrations of 137Cs (median value for dehydrated caps was 4.5 Bq kg(-1) and 5.4 Bq kg(-1) for stipes) while 134Cs was not detected. Natural radionuclide 40K showed 2-3 orders of magnitude greater activity concentration compared to artificial 137Cs in M. gigantea. The activity concentrations of 226Ra from uranium and radium decay series for most of the consignments of M. gigantea examined were below the method's limit of detection. The nominal effective dose equivalent for the Yunnan people from the dietary intake of 137Cs was assessed to be below 0.01 μSv per annum on the average, and that from 40K to be below 0.1 μSv per annum. Data available for the first time on activity concentrations of 137Cs in wild-grown saprobic mushroom from this region of Asia suggest low pollution with radiocesium from fallout there. Hence, the likely health risks from intake of 137Cs from cooked M. gigantea are in practice of mushrooms absent for human consumers there. Because of abundance of mushrooms in Yunnan and high significance of the region as producer and exporter a wider study using many species is necessary to fill a gap on possible radioactive contamination and risk to mushroom consumers.

  15. Duration of gas accumulation before the 2010 Eyjafjallajökull eruption constrained by 210Po-210Pb-226Ra disequilibria

    NASA Astrophysics Data System (ADS)

    Sigmarsson, Olgeir; Gauthier, Pierre-Jean; Condomines, Michel

    2014-05-01

    Excess gas phase in magmas erupting explosively is well known world-wide. However, the origin of this gas phase, in excess of what can be dissolved in the erupting magma at depth, and the duration of gas accumulation, is less well defined. The 2010 mildly explosive eruption at Eyjafjallajökull, Iceland, produced mingled tephra of benmoreiitic and trachytic composition whereas alkali basalt (MgO > 8 %) was emitted during the preceding flank eruption. The silicic tephra of the first explosive phase is composed of three glass types, alkaline rhyolite, mixed benmoreiite, and evolved basalt (MgO < 5 %). The rhyolitic glass is indistinguishable from tephra glass composition emitted during the penultimate eruption of Eyjafjallajökull in 1821-23 AD (Sigmarsson et al., 2011). Tephra from the first explosive phase, emitted on 15 and 17 April, had large 210Po in excess of 210Pb ((210Po/210Pb)0 as high as 2!) and a small, but significant, 210Pb excess over its parent 226Ra ((210Pb/226Ra)0= 1.05 and 1.04, respectively). These excesses suggest rapid accumulation of Po and Rn together with the major gas species in the residual rhyolitic magma from the 1821-23 eruption. The gas most likely originates from the basalt recharge that eventually provoked the eruption. Basalts emitted a month earlier during the flank eruption at Fimmvörðuháls lost all their Po upon eruption and had (210Po/210Pb)0 equal to 0). From a simple model of radon and polonium degassing and accumulation, the mass of basalt magma degassing over the mass of silicic magma accumulating the excess gas can be calculated. Moreover, the duration of gas accumulation can be shown to be close to 300 days. This duration suggests that gas was liberated from the basaltic magma since June 2009, a month that corresponds to the initial seismic swarm beneath Eyjafjallajökull preceding the explosive eruption of 14 April 2010.

  16. Determination of specific activity of (226)Ra, (232)Th and (40)K for assessment of radiation hazards from Turkish pumice samples.

    PubMed

    Turhan, Seref; Gündüz, Lüfullah

    2008-02-01

    The specific activity of (226)Ra, (232)Th and (40)K in 52 Turkish pumice samples collected from 11 geographical areas located in Central Anatolia, Eastern Anatolia, Mediterranean and Aegean regions was determined by gamma-ray spectrometry with a high-purity germanium (HPGe) detector. The specific activity of (226)Ra, (232)Th and (40)K ranged from 12.7+/-0.5 to 256.2+/-9.1Bqkg(-1) with a mean of 89.1+/-65.2Bqkg(-1), 12.3+/-1.0 to 237.9+/-12.2Bqkg(-1) with a mean of 87.0+/-61.4Bqkg(-1) and 300.1+/-5.5 to 1899.0+/-30.8Bqkg(-1) with a mean of 1211.9+/-419.8Bqkg(-1), respectively. Elemental concentrations were determined for U (from 1.0 to 20.7ppm with a mean of 7.2+/-5.3ppm), Th (from 3.0 to 58.6ppm with a mean of 21.4+/-15.1ppm) and K (from 1.0 to 6.1% with a mean of 3.9+/-1.3%). The radium equivalent activity (Ra(eq)), the activity index, the emanation coefficient, the (222)Rn mass exhalation rate, the indoor absorbed dose rate and the effective dose rate were estimated for the radiation hazard of the natural radioactivity in all samples. The calculated mean Ra(eq) value was 306.6+/-177.7Bqkg(-1) (54.6+/-5.5 to 737.6+/-49.0Bqkg(-1)) for all pumice samples. This value is lower than the recommended limit value of 370Bqkg(-1) for building raws and products. The emanation coefficient and the (222)Rn mass exhalation rate of all samples ranged from 29.4 to 42.9% with a mean of 36.2% and from 11.0 to 196.4microBqkg(-1)s(-1) with a mean of 73.5microBqkg(-1)s(-1), respectively. The mean indoor absorbed dose rate and the corresponding mean effective dose rate were 274.6+/-153.6nGyh(-1) (50.4-644.6nGyh(-1)) and 1.35+/-0.75mSvy(-1) (0.24-3.16mSvy(-1)), respectively. For all pumice samples the mean indoor absorbed dose rate is about three times higher than the population-weighted average of 84nGyh(-1), while the mean effective dose rate values except for PUM 05, PUM 06, PUM 10 and PUM 15 exceed the dose criterion of 1mSvy(-1).

  17. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    PubMed

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values.

  18. Investigating groundwater properties in high annual recharge rate aquifers using 14c and 226ra : example of the fontainebleau sands aquifer (paris basin, france)

    NASA Astrophysics Data System (ADS)

    Chabault, C.; Barbecot, F.; Ghaleb, B.; Dever, L.

    2003-04-01

    Aquifers with high annual recharge rates constitute prominent groundwater resource for freshwater supplies. However, they are very sensitive to pollutants. Moreover, in such cases, the establishment of recharge rates based on radiometric age measurements requires specific methodological approaches as in the example of the aquifer of the Fontainebleau Sands, in the Paris Basin, that we investigate here. It constitutes one of the major aquifers exploited for freshwater supply in the area. It is part of the Beauce aquifer that is underlain by the Romainville aquitard (green clays of Lower Sannoisian age) and overlain by millstone clays of Plio-Quaternary age. The Fontainebleau Sands aquifer outcrops principally in valleys, in the southern part of the Paris Basin (1). Groundwaters from the Fontainebleau Sands aquifer were sampled along a flow-path line in order to determine their geochemical evolution through time. Chemical and stables isotope compositions provide information on mineralisation processes during recharge. They indicate either carbonate dissolution up to saturation during the recharge or addition of recent water along the flow lines. These two possibilities will be discriminated using time tracers. 14C-derived age estimates (T1/2 = 5750 years) are not precise enough to assess residence times of recent waters. We will tentatively use 226 Ra measurements (T1/2 = 1620 years) to add constraints on age-estimates. 14C vs. 226Ra age models already tested in the Astian aquifer from southern France (2), are expected to provide further information on water-rock interactions occurring within the aquifer of the Fontainebleau Sands. (1) Bariteau. A., 1996, Modélisation géochimique d’un aquifère, la nappe de l’oligocène en Beauce et l’altération des Sables de Fontainebleau. Ecoles des Mines de Paris, pp. 179 (2) Barbecot, F., Dever, L., Hillaire-Marcel, C., Gibert, E., Travi, Y. And Marlin, C., 1999. Isotopic evidence for geochemical provinces in the Astian

  19. Flank eruptions of Mt Etna during the Greek-Roman and Early Medieval periods: New data from 226Ra-230Th dating and archaeomagnetism

    NASA Astrophysics Data System (ADS)

    Branca, Stefano; Condomines, Michel; Tanguy, Jean-Claude

    2015-10-01

    In this paper, we present new data from 226Ra-230Th dating and archaeomagnetism with the aim of improving the knowledge of the flank eruptions that occurred at Mt Etna during the Greek-Roman and Early Medieval periods, as defined in the new geological map of the volcano. The combination of the two dating techniques demonstrates that three major flank eruptions occurred on the lower north and west flanks during Greek-Roman epochs, producing large scoria cones and extensive lava flows. In particular, the Mt Ruvolo and Mt Minardo events highly impacted the territory of the west flank, notably by damming the Simeto River. The new data of the Millicucco and Due Monti lava flows, on the lower north-east flank, indicate a younger age than their stratigraphic ages quoted in the 2011 geological map, since they occurred around 700 and 500 AD, respectively. None of the large flank eruptions occurring on the lower slopes of Etna during the Early Medieval age are reported in the historical sources. Overall, our paper shows that a comprehensive assessment of eruptions at Mount Etna in the last three millennia can only be achieved through a multidisciplinary approach.

  20. Current (1984) status of the study of /sup 226/Ra and /sup 228/Ra in humans at the Center for Human Radiobiology

    SciTech Connect

    Rundo, J.; Keane, A.T.; Lucas, H.F.; Schlenker, R.A.; Stebbings, J.H.; Stehney, A.F.

    1984-01-01

    The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to /sup 226/Ra and /sup 228/Ra. Included are 4863 dial painters (mostly women) and non-laboratory employees of the radium dial industry, 410 laboratory workers, 399 persons who received radium for supposed therapeutic effects, and 112 in other categories. Body contents of radium have been measured in 1916 of the dial workers and about one-half of the subjects in the other groups. Bone sarcomas, carcinomas of the paranasal sinuses and mastoids, and deterioration of skeletal tissue are still the only effects unequivocally attributable to internal radium. Excess leukemias have not been observed and other malignancies, if in excess, appear more likely to be related to external gamma radiation or radon than to internal radium. Positive correlations with radium burdens have been found for the incidence of benign exostoses among subjects exposed to radium before age 18 and for shortened latency of ocular cataracts. 26 references, 3 figures, 5 tables.

  1. Mean residence time of the shelf water in the East China and the Yellow Seas determined by 228Ra/226Ra measurements

    NASA Astrophysics Data System (ADS)

    Nozaki, Yoshiyuki; Kasemsupaya, Vimonrut; Tsubota, Hiroyuki

    1989-11-01

    Increasing attention of oceanographers has recently been paied on East Asian marginal seas regarding their role on the global environment, yet geochemical investigations have been few to date. We here report new data on the distribution of 228Ra and 226Ra in the surface water of the East China and the Yellow seas in an effort to constrain the time necessary for the coastal and shelf waters to exchange with offshore waters. Such information is needed in evaluating the exchange of heat and water across the air-sea interface that affects the local climate and the fate of pollutants, nutrients and weathering products supplied from the continent. Based on the Ra isotope signals, we have estimated that the shelf water component contributes ˜ 20 % of the Tsushima Current water passing through the Tsushima Strait and the mean residence time for the shelf water to mix with the Kuroshio surface water is ˜ 2.3 years. As many of materials derived from the continent such as heavy metals and the nutrients have their mean residence times less than a few months in the nearshore and shelf waters, they must largely deposit on the shelf sediments prior to the transport from the shelf to the open sea by mixing.

  2. Relative radiosensitivity of bone tumor induction among beagles as a function of age at injection of {sup 239}Pu or {sup 226}Ra

    SciTech Connect

    Lloyd, R.D.; Taylor, G.N.; Jee, W.S.S.; Miller, S.C.

    1999-01-01

    A comparison was made of the response to induction of skeletal malignancy from exposure of beagles to monomeric {sup 239}Pu or to {sup 226}Ra as juveniles (3 mo of age), young adults (1.5 y of age), or mature adults (5 y of age). This indicated that of these age groups, animals injected as young adults are most sensitive per Gy of average skeletal dose evaluated at 1 y before death. Dogs exposed either as juveniles or as mature adults appeared to be less sensitive. Relative radiosensitivities (RRS) of juvenile and mature beagles ranged between about 0.3 and 0.7 that of dogs injected as young adults. Mean values of RRS for both radionuclides were about 0.5, but RRS values derived from dogs given monomeric {sup 239}Pu appeared to be most reliable and were 0.27 {+-} 0.09 for dogs injected as juveniles and 0.41 {+-} 0.13 for animals exposed as mature adults.

  3. Activity concentrations of 226Ra, 232Th, 40K and 137Cs radionuclides in Turkish medicinal herbs, their ingestion doses and cancer risks

    NASA Astrophysics Data System (ADS)

    Parmaksız, Aydın; Ağuş, Yusuf

    2014-11-01

    Twenty-two medicinal herb samples, each representing a distinct species, were collected from Turkish markets and measured by the gamma spectrometric method. The activity concentration of 226Ra in medicinal herbs was found in the range of minimum detectable activity (MDA) and 15.1 ± 2.2 Bqkg-1. The activity concentration of 232Th ranged from MDA values to 3.5 ± 0.8 Bqkg-1. The activity concentration of 40K varied between 50.0 ± 16.8 and 1311.5 ± 57.3 Bqkg-1. All 137Cs activity concentrations of medicinal herbs were found to have lower than MDA values. The bone surface dose, lower large intestine and colon doses were found to be 182.9, 18.8 and 18.7 µSvy-1, respectively. The highest committed effective dose originated from the annual ingestion of 1 kg medicinal herb was calculated notably low as 9.0 µSv. The cancer risk of ingestion of medicinal herbs was found to be small enough to be neglected. The selected Turkish medicinal herbs are considered safe for human consumption.

  4. Soil to rice transfer factors for (226)Ra, (228)Ra, (210)Pb, (40)K and (137)Cs: a study on rice grown in India.

    PubMed

    Karunakara, N; Rao, Chetan; Ujwal, P; Yashodhara, I; Kumara, Sudeep; Ravi, P M

    2013-04-01

    India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed at the evaluation of radionuclide transfer factors (F(v)) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural ((226)Ra, (228)Ra, (40)K, and (210)Pb) and artificial ((137)Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the (226)Ra and (228)Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain (40)K transfer factor varied in the range of 6.5 × 10(-1) to 2.9 with a mean of 0.15 × 10(1), and of (210)Pb varied in the range of <1.2 × 10(-2) to 8.1 × 10(-1) with a mean of 1.4 × 10(-1), and of (137)Cs varied in the range of 6.6 × 10(-2) to 3.4 × 10(-1) with a mean of 2.1 × 10(-1). The mean values of un-hulled grain to white rice processing retention factors (F(r)) were 0.12 for (40)K, 0.03 for (210)Pb, and 0.14 for (137)Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10(-1), 4.2 × 10(-3), and 3.0 × 10(-2) for (40)K, (210)Pb, and (137)Cs, respectively. The study has shown that the transfer of (40)K was higher for above the ground organs than for the root, but (210)Pb and (137)Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower. Copyright © 2012 Elsevier Ltd. All rights

  5. Mount Etna eruptions of the last 2,750 years: revised chronology and location through archeomagnetic and 226Ra-230Th dating

    NASA Astrophysics Data System (ADS)

    Tanguy, Jean-Claude; Condomines, Michel; Le Goff, Maxime; Chillemi, Vito; La Delfa, Santo; Patanè, Giuseppe

    2007-09-01

    A careful re-examination of the well-known written documents pertaining to the 2,750-year-long historical period of Mount Etna was carried out and their interpretation checked through the high-accuracy archeomagnetic method (>1,200 large samples), combined with the 226Ra-230Th radiochronology. The magnetic dating is based upon secular variation of the direction of the geomagnetic field (DGF) and estimated to reach a precision of ±40 years for the last 1,200 years, and ±100 to 200 years up to circa 150 B.C. Although less precise, the 226Ra-230Th method provides a unique tool for distinguishing between historic and prehistoric lavas, which in some cases might have similar DGFs. We show that despite the abundance of details on ancient historical eruptions, the primary sources of information are often too imprecise to identify their lava flows and eruptive systems. Most of the ages of these lavas, which are today accepted on the geological maps and catalogues, were attributed in the 1800s on the basis of their morphology and without any stratigraphical control. In fact, we found that 80% of the “historically dated” flows and cones prior to the 1700s are usually several hundreds of years older than recorded, the discrepancies sometimes exceeding a millennium. This is proper the case for volcanics presumed of the “1651 east” (actually ˜1020), “1595” (actually two distinct flows, respectively, ˜1200 and ˜1060), “1566” (˜1180), “1536” (two branches dated ˜1250 and ˜950), “1444” (a branch dated ˜1270), “1408” (lower branches dated ˜450 and ˜350), “1381” (˜1160), “1329” (˜1030), “1284” (˜1450 and ˜700), “1169 or 812” (˜1000) eruptions. Conversely, well-preserved cones and flows that are undated on the maps were produced by recent eruptions that went unnoticed in historical accounts, especially during the Middle Ages. For the few eruptions that are recorded between A.D. 252 and 750 B.C., none of their presumed lava

  6. Compositional variation and 226Ra-230Th model ages of axial lavas from the southern Mid-Atlantic Ridge, 8°48'S

    NASA Astrophysics Data System (ADS)

    Haase, K. M.; Brandl, P. A.; Devey, C. W.; Hauff, F.; Melchert, B.; Garbe-Schönberg, D.; Kokfelt, T. F.; Paulick, H.

    2016-01-01

    We present geological observations and geochemical data for the youngest volcanic features on the slow spreading Mid-Atlantic Ridge at 8°48'S that shows seismic evidence for a thickened crust and excess magma formation. Young lava flows with high sonar reflectivity cover about 14 km2 in the axial rift and were probably erupted from two axial volcanic ridges each of about 3 km in length. Three different lava units occur along an about 11 km long portion of the ridge, and lavas from the northern axial volcanic ridge differ from those of the southern axial volcanic ridge and surrounding lava flows. Basalts from the axial rift flanks and from a pillow mound within the young flows are more incompatible element depleted than those from the young volcanic field. Lavas from this volcanic area have 226Ra-230Th disequilibria model ages of 1000 and 4000 years whereas the older lavas from the rift flank and the pillow mound, but also some of the lava field, are older than 8000 years. Glasses from the northern and southern ends of the southern lava unit indicate up to 100°C cooler magma temperatures than in the center and increased assimilation of hydrothermally altered material. The compositional heterogeneity on a scale of 3 km suggests small magma batches rising vertically from the mantle to the surface without significant lateral flow and mixing. The observations on the 8°48'S lava field support the model of low-frequency eruptions from single ascending magma batches that has been developed for slow spreading ridges.

  7. Development of a neural network approach to characterise (226)Ra contamination at legacy sites using gamma-ray spectra taken from boreholes.

    PubMed

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul

    2015-02-01

    There are a large number of sites across the UK and the rest of the world that are known to be contaminated with (226)Ra owing to historical industrial and military activities. At some sites, where there is a realistic risk of contact with the general public there is a demand for proficient risk assessments to be undertaken. One of the governing factors that influence such assessments is the geometric nature of contamination particularly if hazardous high activity point sources are present. Often this type of radioactive particle is encountered at depths beyond the capabilities of surface gamma-ray techniques and so intrusive borehole methods provide a more suitable approach. However, reliable spectral processing methods to investigate the properties of the waste for this type of measurement have yet to be developed since a number of issues must first be confronted including: representative calibration spectra, variations in background activity and counting uncertainty. Here a novel method is proposed to tackle this issue based upon the interrogation of characteristic Monte Carlo calibration spectra using a combination of Principal Component Analysis and Artificial Neural Networks. The technique demonstrated that it could reliably distinguish spectra that contained contributions from point sources from those of background or dissociated contamination (homogenously distributed). The potential of the method was demonstrated by interpretation of borehole spectra collected at the Dalgety Bay headland, Fife, Scotland. Predictions concurred with intrusive surveys despite the realisation of relatively large uncertainties on activity and depth estimates. To reduce this uncertainty, a larger background sample and better spatial coverage of cores were required, alongside a higher volume better resolution detector. Copyright © 2014. Published by Elsevier Ltd.

  8. Plant uptake of (238)U, (235)U, (232)Th, (226)Ra, (210)Pb and (40)K from a coal ash and slag disposal site and control soil under field conditions: A preliminary study.

    PubMed

    Skoko, Božena; Marović, Gordana; Babić, Dinko; Šoštarić, Marko; Jukić, Mirela

    2017-06-01

    The aim of this study was to investigate the uptake of (238)U, (235)U, (232)Th, (226)Ra, (210)Pb and (40)K by plants that grow on a coal ash and slag disposal site known for its higher content of naturally occurring radionuclides. Plant species that were sampled are common for the Mediterranean flora and can be divided as follows: grasses & herbs, shrubs and trees. To compare the activity concentrations and the resultant concentration ratios of the disposal site with those in natural conditions, we used control data specific for the research area, obtained for plants growing on untreated natural soil. Radionuclide activity concentrations were determined by high resolution gamma-ray spectrometry. Media parameters (pH, electrical conductivity and organic matter content) were also analysed. We confirmed significantly higher activity concentrations of (238)U, (235)U, (226)Ra and (210)Pb in ash and slag compared to control soil. However, a significant increase in the radionuclide activity concentration in the disposal site's vegetation was observed only for (226)Ra. On the contrary, a significantly smaller activity concentration of (40)K in ash and slag had no impact on its activity concentration in plant samples. The calculated plant uptake of (238)U, (235)U, (226)Ra and (210)Pb is significantly smaller in comparison with the uptake at the control site, while it is vice versa for (40)K. No significant difference was observed between the disposal site and the control site's plant uptake of (232)Th. These results can be the foundation for further radioecological assessment of this disposal site but also, globally, they can contribute to a better understanding of nature and long-term management of such disposal sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Comparative toxicity of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, and /sup 252/Cf in C57BL/Do black and albino mice

    SciTech Connect

    Taylor, G.N.; Mays, C.W.; Lloyd, R.D.; Gardner, P.A.; Talbot, L.R.; McFarland, S.S.; Pollard, I.A.; Atherton, D.R.; VanMoorhem, D.; Brammer, D.

    1983-09-01

    Groups of C57BL/Do (black and albino) mice were injected with graded activities of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, or /sup 252/Cf and were followed throughout life. Bone sarcoma was the principal radiation-induced end point, and the risks associated with average skeletal doses of the four transuranium radionuclides, relative to radium, were determined. The relative biological effectiveness (RBE) was calculated for each emitter by dividing its risk coefficient (bone sarcomas per 10(/sup 6/) mouse-rad) by the risk coefficient for /sup 226/Ra. Combined data for males and females in both black and albino mice gave the following values +/- SD for the RBE relative to /sup 226/Ra . 1.0: /sup 239/Pu . 15.3 +/- 3.9, /sup 241/Am . 4.9 +/- 1.4, /sup 249/Cf . 5.0 +/- 1.4, and /sup 252/Cf . 2.6 +/- 0.8. About 70% of the tumors occurred in the axial skeleton, and the risk coefficient for females averaged about four times higher than for males when all five nuclides were included. The RBE of fission fragment irradiation from /sup 252/Cf for cancer induction, relative to alpha irradiation, for the combined data in all of the animals given /sup 252/Cf and /sup 249/Cf, was 0.02 +/- 0.28, in agreement with the calculated theoretical value of 0.03, based on the ratio of summed track lengths in tissue.

  10. Comparative toxicity of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, and /sup 252/Cf in C57BL/Do black and albino mice

    SciTech Connect

    Taylor, G.N.; Mays, C.W.; Lloyd, R.D.; Gardner, P.A.; TAlbot, L.R.; McFarland, S.S.; Pollard, T.A.; Atherton, D.R.; vanMoorhem, D.; Brammer, D.

    1983-09-01

    Groups of C57BL/Do (black and albino) mice were injected with graded activities of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, or /sup 252/Cf and were followed throughout life. Bone sarcoma was the principal radiation-induced end point, and the risks associated with average skeletal doses of the four transuranium radionuclides, relative to radium, were determined. The relative biological effectiveness (RBE) was calculated for each emitter by dividing its risk coefficient (bone sarcomas per 10/sup 6/ mouse-rad) by the risk coefficient for /sup 226/Ra. Combined data for males and females in both black and albino mice gave the following values +- SD for the RBE relative to /sup 226/Ra = 1.0: /sup 239/Pu = 15.3 +- 3.9, /sup 241/Am = 4.9 +- 1.4, /sup 249/Cf = 5.0 +- 1.4, and /sup 252/Cf = 2.6 +- 0.8. About 70% of the tumors occurred in the axial skeleton, and the risk coefficient for females averaged about four times higher than for males when all five nuclides were included. The RBE of fission fragment irradiation from /sup 252/Cf for cancer induction, relative to ..cap alpha.. irradiation, for the combined data in all of the animals given /sup 252/Cf and /sup 249/Cf, was 0.02 +- 0.28, in agreement with the calculated theoretical value of 0.03, based on the ratio of summed track lengths in tissue.

  11. Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India.

    PubMed

    Lenka, Pradyumna; Sahoo, S K; Mohapatra, S; Patra, A C; Dubey, J S; Vidyasagar, D; Tripathi, R M; Puranik, V D

    2013-03-01

    A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources.

  12. Activity ratios of (234)U/(238)U and (226)Ra/(228)Ra for transport mechanisms of elevated uranium in alluvial aquifers of groundwater in south-western (SW) Punjab, India.

    PubMed

    Kumar, A; Karpe, R K; Rout, S; Gautam, Y P; Mishra, M K; Ravi, P M; Tripathi, R M

    2016-01-01

    The concentrations of total dissolved uranium (U), its isotopic composition ((234)U, (235)U, (238)U) and two long lived Ra isotopes ((226)Ra and (228)Ra) in alluvial aquifers of groundwater were determined to investigate the groundwater flow pattern in the south-western (SW) Punjab, India. Particular attention was given to the spatial variability of activity ratios (ARs) of (234)U/(238)U and (226)Ra/(228)Ra to predict the possible sources and supply process of U into the water from the solid phase. The measured groundwater (234)U/(238)U ARs were ∼1 or >1 in the shallow zone (depth < 30 m) with high U concentration and <1 in the deeper zone (depth > 30 m) with relatively low U concentration. The simultaneous elevated U concentration and (234)U/(238)U ARs in waters were possibly due to differences in imprints of rock-water interactions under hydrologic conditions. However, (234)U/(238)U ARs < 1 clearly indicate the lack of recharge from surface water to groundwater leading to (234)U deficit in groundwater. This deficit might be also attributed to alpha recoil processes under strong dissolution. Overall, the decreasing pattern of (234)U/(238)U ARs observed from SE to SW or NW ward clearly indicates a groundwater flow paths from SE to SW/NW. Similarly, (226)Ra/(238)U ARs < 1 for all water samples reflect that the precursor (238)U is fairly mobile relative to (226)Ra. This might be due to unusually high amount of (238)U in groundwaters and subsequently the different geochemistry of the two isotopes. On the other hand, (226)Ra/(228)Ra ARs in groundwaters varied widely and observed about 50-300 times higher than (238)U/(232)Th ARs in granitic rocks or soils. Such elevation in ARs might be attributed to different dissolution properties of their parents during water-rock interactions or lattice damage during decay or local enrichments of uranium in the aquifers.

  13. Activity concentration and radiological impact assessment of 226Ra, 228Ra and 40K in drinking waters from (OML) 30, 58 and 61 oil fields and host communities in Niger Delta region of Nigeria.

    PubMed

    Agbalagba, E O; Avwiri, G O; Ononugbo, C P

    2013-02-01

    This paper presents the concentrations of naturally occurring radionuclides ((226)Ra, (228)Ra and (40)K) measured in hand dug wells, boreholes and river waters collected from three oil mineral leases (OML) 30, 58 & 61 oil and gas fields onshore of the Niger delta, using gamma spectroscopy. Fifty-four water samples from the three sources of drinking water supply were collected within the oil fields and host communities and three water samples from a control site. The results showed average activity concentrations of (226)Ra, (228)Ra and (40)K as 8.9 ± 1.0, 8.1 ± 0.9 and 39.8 ± 3.3 respectively for hand dug wells, 4.4 ± 0.8, 4.6 ± 0.5 and 28.5 ± 3.0 for borehole water and 8.2 ± 1.0, 6.7 ± 0.7 and 32.1 ± 3.5 for river water respectively. These (226)Ra, (228)Ra and (40)K average are well above the WHO permissible levels of 1.0, 0.1 and 10 BqL(-1) respectively and also above the control values. Although the hazard indices calculated are still within their tolerable levels, the estimated committed effective dose due to intake of the sampled water for all the four age groups considered are far above the ICPR 0.1 mSvyr(-1) maximum permissible limit. The result indicates some level of water pollution in the studied area. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Timing of degassing and plagioclase growth in lavas erupted from Mount St. Helens, 2004-2005, from 210Po-210Pb-226Ra disequilibria: Chapter 37 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Reagan, Mark K.; Cooper, Kari M.; Pallister, John S.; Thornber, Carl R.; Wortel, Matthew; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Disequilibrium between 210Po, 210Pb, and 226Ra was measured on rocks and plagioclase mineral separates erupted during the first year of the ongoing eruption of Mount St. Helens. The purpose of this study was to monitor the volatile fluxing and crystal growth that occurred in the weeks, years, and decades leading up to eruption. Whole-rock samples were leached in dilute HCl to remove 210Po precipitated in open spaces. Before leaching, samples had variable initial (210Po) values, whereas after leaching, the groundmasses of nearly all juvenile samples were found to have had (210Po) ≈ 0 when they erupted. Thus, most samples degassed 210Po both before and after the magmas switched from open- to closed-system degassing. All juvenile samples have (210Pb)/(226Ra) ratios within 2 δ of equilibrium, suggesting that the magmas involved in the ongoing eruption did not have strong, persistent fluxes of 222Rn in or out of magmas during the decades and years leading to eruption. These equilibrium values also require a period of at least a century after magma generation and the last significant differentiation of the Mount St. Helens dacites. Despite this, the elevated (210Pb)/(226Ra) value measured in a plagioclase mineral separate from lava erupted in 2004 suggests that a significant proportion of this plagioclase grew within a few decades of eruption. The combined dataset suggests that for most 2004-5 lavas, the last stage of open-system degassing of the dacite magmas at Mount St. Helens is confined to the period between 1-2 years and 1-2 weeks before eruption, whereas plagioclase large enough to be included in the mineral separate grew around the time of the 1980s eruption or earlier.

  15. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    PubMed

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland.

  16. 228Ra/226Ra ratio and 7Be concentration in the Sea of Japan as indicators for water transport: comparison with migration pattern of Fukushima Dai-ichi NPP-derived 134Cs and 137Cs.

    PubMed

    Inoue, M; Furusawa, Y; Fujimoto, K; Minakawa, M; Kofuji, H; Nagao, S; Yamamoto, M; Hamajima, Y; Yoshida, K; Nakano, Y; Hayakawa, K; Oikawa, S; Misonoo, J; Isoda, Y

    2013-12-01

    To assess the migration patterns of radiocesium emitted from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), we analyzed (228)Ra/(226)Ra ratios and (7)Be concentrations and compared them with (134)Cs and (137)Cs concentrations in seawater samples collected within the Sea of Japan before and after the FDNPP accident (i.e., during the period 2007-2012) using low-background γ-spectrometry. The (228)Ra/(226)Ra ratios in surface waters exhibited lateral and seasonal variations, reflecting the flow patterns of surface water. This indicates the transport patterns of the FDNPP-derived radiocesium by surface water. Cosmogenic (7)Be (half-life: 53.3 d) exhibited markedly high concentrations (5-10 mBq/L) at depths shallower than 50 m, with concentrations decreasing steeply (0.2-2 mBq/L) at depths of 50-250 m. The distribution of (7)Be concentrations suggests that the downward delivery of the FDNPP-derived radiocesium to below 50 m depth was negligible for a few months prior to its removal from the Sea of Japan. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Reply to Comment on “Steady-state 226Ra/230Th disequilibrium in mantle minerals: implications for melt transport rates in island arcs” by R. George, M. Reagan, S. Turner, J. Gill, B. Bourdon

    NASA Astrophysics Data System (ADS)

    Feineman, M. D.; DePaolo, D. J.

    2004-12-01

    We agree with George et al. that high 226Ra/ 230Th and correlated Ba/Th, 238U/ 230Th, and other elemental and isotopic ratios are the result of fluid addition to the wedge. The Feineman and DePaolo [Earth Planet. Sci. Lett. 215 (2003) 339-355] manuscript addresses more specifically the pathway followed by the fluid en route to the surface. In particular, we address whether the 226Ra/ 230Th data directly yield the total time available for the fluid to migrate from the point of origin in the slab to the melting region in the wedge, and ultimately to the surface with the melt. All of the processes involved in generating arc volcanism would of necessity have to take place very rapidly within the constraints proposed by George et al. The alternative is that the upward fluid movement is hindered by the fluid flow regime and solid mantle flow, allowing more time for reaction with the mantle wedge. There is evidence in the U-series data for more than one time scale, and our model helps to explain how this could come about. The extent to which grainscale 226Ra/ 230Th disequilibrium affects the inferred melt transport time is yet another issue, and this could be achieved either with the small-degree melt mechanism we discussed or by additional effects associated with melt and fluid migration at later stages in the melt generation process. We agree that the final melt transport event is likely to happen quickly. One of the most puzzling features of volcanic arcs is that the volcanic front emerges considerably behind the presumed location of primary water release from the subducting slab (depth to slab is ˜120 km beneath the volcanic front, as opposed to the predicted ˜80 km). This offset between the expected site of fluid release and the location of the volcanic front can be attributed to coupled transport of the fluid—in the form of hydrous minerals, such as amphibole and/or phlogopite in the wedge [J. Geophys. Res. 97 (1992) 2037-2070] or redirection of the melt due to

  18. Use of radiometric ((234/238)U and (228/226)Ra) and mass spectrometry ((87/86)Sr) methods for studies of the stability of groundwater reservoirs in Central Poland.

    PubMed

    Grabowski, P; Bem, H; Romer, R L

    The uranium ((234)U/(238)U) and radium ((228)Ra/(226)Ra) activity ratios and (87)Sr/(86)Sr isotopic ratio in thermal groundwater, subsurface water (groundwater) and river water from Poddebice and Uniejow were determined. The uranium and radium activity ratios and strontium isotopic ratio varied from 0.629 to 1.471, from 0.396 to 4.961 and from 0.708438 to 0.710344, respectively. The results for the thermal groundwater samples showed that the radiometric method together with mass spectrometry stable strontium isotope ratio measurements can be used for underground water transport studies. On the basis of the uranium and radium activity and the strontium isotopic ratio differences in subsurface water (groundwater) and in river water, any possible water influx between these adjacent reservoirs can be observed. The obtained results exclude any water transport from surface and subsurface water to thermal ground water reservoirs in this region of Poland.

  19. Mid-ocean ridge basalt generation along the slow-spreading, South Mid-Atlantic Ridge (5-11°S): Inferences from 238U-230Th-226Ra disequilibria

    NASA Astrophysics Data System (ADS)

    Turner, Simon; Kokfelt, Thomas; Hauff, Folkmar; Haase, Karsten; Lundstrom, Craig; Hoernle, Kaj; Yeo, Isobel; Devey, Colin

    2015-11-01

    U-series disequilibria have provided important constraints on the physical processes of partial melting that produce basaltic magma beneath mid-ocean ridges. Here we present the first 238U-230Th-226Ra isotope data for a suite of 83 basalts sampled between 5°S and 11°S along the South Mid-Atlantic Ridge. This section of the ridge can be divided into 5 segments (A0-A4) and the depths to the ridge axis span much of the global range, varying from 1429 to 4514 m. Previous work has also demonstrated that strong trace element and radiogenic isotope heterogeneity existed in the source regions of these basalts. Accordingly, this area provides an ideal location in which to investigate the effects of both inferred melt column length and recycled materials. 226Ra-230Th disequilibria indicate that the majority of the basalts are less than a few millennia old such that their 230Th values do not require any age correction. The U-Th isotope data span a significant range from secular equilibrium up to 32% 230Th excess, also similar to the global range, and vary from segment to segment. However, the (230Th/238U) ratios are not negatively correlated with axial depth and the samples with the largest 230Th excesses come from the deepest ridge segment (A1). Two sub-parallel and positively sloped arrays (for segments A0-2 and A3 and A4) between (230Th/238U) and Th/U ratios can be modelled in various ways as mixing between melts from peridotite and recycled mafic lithologies. Despite abundant evidence for source heterogeneity, there is no simple correlation between (230Th/238U) and radiogenic isotope ratios suggesting that at least some of the trace element and radiogenic isotope variability may have been imparted to the source regions >350 kyr prior to partial melting to produce the basalts. In our preferred model, the two (230Th/238U) versus Th/U arrays can be explained by mixing of melts from one or more recycled mafic lithologies with melts derived from chemically heterogeneous

  20. Dynamics of melt generation beneath mid-ocean ridge axes: Theoretical analysis based on [sup 238]U-[sup 230]Th-[sup 226]Ra and [sup 235]U-[sup 231]Pa disequilibria

    SciTech Connect

    Zhenwei Qin )

    1993-04-01

    Although slow melting favors the generation of basaltic melt from a mantle matrix with large radioactive disequilibrium between two actinide nuclides (McKenzie, 1985a), it results in long residence time in a magma chamber, during which the disequilibrium may be removed. An equilibrium melting model modified after McKenzie (1985a) is presented here which suggests that, for a given actinide parent-daughter pair, there exists a specific melting rate at which disequilibrium between these two nuclides reaches its maximum. This melting rate depends on the decay constant of the daughter nuclide concerned and the magma chamber volume scaled to that of its source. For a given scaled chamber size, large radioactive disequilibrium between two actinide nuclides in basalts will be observed if the melting rate is such that the residence time of the magma in the chamber is comparable to the mean life of the daughter nuclide. With a chamber size 1% in volume of the melting source, the melting rates at which maximum disequilibrium in basalts is obtained are 10[sup [minus]7], 2 [times] 10[sup [minus]7], and 3 [times] 10[sup [minus]6] y[sup [minus]1], respectively for [sup 238]U-[sup 230]Th, [sup 235]U-[sup 231]Pa, and [sup 230]Th-[sup 226]Ra. This implies that, while large disequilibrium between [sup 238]U-[sup 230]Th and between [sup 235]U-[sup 231]Pa may occur together, large [sup 230]Th-[sup 226]Ra disequilibrium will not coexist with large [sup 238]U-[sup 230]Th disequilibrium, consistent with some observations. The active mantle melting zone which supplies melt to a ridge axis is inferred to be only about 10 km thick and 50 km wide. The fraction of melt present in such a mantle source at any time is about 0.01 and 0.04, respectively, if melting rate is 10[sup [minus]7] and 10[sup [minus]6] y[sup [minus]1]. The corresponding residence time of the residual melt in the matrix is 10[sup 5] and 4 [times] 10[sup 4] y. 27 refs., 3 figs.

  1. A comparison of the natural survival of beagle dogs injected intravenously with low levels of sup 239 Pu, sup 226 Ra, sup 228 Ra, sup 228 Th, or sup 90 Sr

    SciTech Connect

    Bruenger, F.W.; Miller, S.C.; Lloyd, R.D. )

    1991-06-01

    The natural survival, relative to properly chosen controls, of 26 beagle dogs injected once intravenously with an average of 0.58 +/- 0.04 kBq {sup 239}Pu/kg, 23 dogs injected with 2.31 +/- 0.43 kBq {sup 226}Ra/kg, 13 dogs injected with 1.84 +/- 0.26 kBq {sup 228}Ra/kg, 12 dogs injected with 0.56 +/- 0.030 kBq {sup 228}Th/kg, and 12 dogs injected with 21.13 +/- 1.74 kBq {sup 90}Sr/kg was evaluated statistically. The amounts of these radionuclides are related directly to the estimated maximum permissible body burdens for humans suggested in ICRP II (1959). They constitute a level of exposure that initially was assumed to cause no deleterious effects in dogs. This study had two objectives: (1) identification of homogeneous control groups against which to evaluate the survival of the irradiated groups and (2) comparison of the survival characteristics and estimation of mortality or hazard rate ratios for control dogs vs dogs injected with the baseline dosages given above. It was shown, by goodness-of-fit plots, that the Cox proportional hazards model was an appropriate method of analysis. Therefore, covariates that possibly could influence survival were tested for significance. Only the effects of grand mal seizure, which is caused in epileptic dogs by an external stimulus and can be fatal if untreated, were significant (P less than 0.0001). Consequently, in the final model, death from grand mal seizure was considered as accidental. After censoring the dogs dying from grand mal seizure, it was established that the data for the control groups from previous and contemporary experiments could be pooled. The change in hazard rates relative to controls resulting from exposure to the baseline radionuclide level was modest, 1.6 times for {sup 239}Pu (P = 0.033), 1.0(4) for {sup 226}Ra (P = 0.86), 1.9 for {sup 228}Ra (P = 0.035), 2.5 for {sup 228}Th (P less than 0.001), and 0.52 for {sup 90}Sr (P = 0.041).

  2. A sequential method for the determination of 210Pb, 226Ra, and uranium and thorium radioisotopes by LSC and alpha-spectrometry.

    PubMed

    Lozano, J C; Tomé, F Vera; Rodríguez, P Blanco; Prieto, C

    2010-01-01

    A procedure for the determination of (210)Pb, and alpha-emitting radioisotopes of uranium, thorium, and radium from the same aliquot of a sample has been proposed. The key step consisted in the recovery of Pb(II) and Ra by precipitation of insoluble Pb(NO(3))(2), the uranium and thorium radioisotopes remaining in solution. Afterwards, the fractions were handled by specific, well consolidated procedures. Lead-210 was determined by the LSC technique while the uranium, thorium, and radium radioisotopes were measured with silicon alpha-spectrometers. The procedure was applied to a reference sample and several environmental samples obtaining satisfactory results.

  3. Porosity of the melting zone and variations in the solid mantle upwelling rate beneath Hawaii: Inferences from {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria

    SciTech Connect

    Sims, K.W.W.; DePaolo, D.J.; Murrell, M.T.; Baldridge, W.S.; Goldstein, S.; Clague, D.; Jull, M.

    1999-12-01

    Measurements of {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria in a suite of tholeiitic-to-basanitic lavas provide estimates of porosity, solid mantle upwelling rate and melt transport times beneath Hawaii. The observation that ({sup 230}Th/{sup 238}U) {gt} 1 indicates that garnet is required as a residual phase in the magma sources for all of the lavas. Both chromatographic porous flow and dynamic melting of a garnet peridotite source can adequately explain the combined U-Th-Ra and U-Pa data for these Hawaiian basalts. For chromatographic porous flow, the calculated maximum porosity in the melting zone ranges from 0.3--3% for tholeiites and 0.1--1% for alkali basalts and basanites, and solid mantle upwelling rates range from 40 to 100 cm/yr for tholeiites and from 1 to 3 cm/yr for basanites. For dynamic melting, the escape or threshold porosity is 0.5--2% for tholeiites and 0.1--0.8% for alkali basalts and basanites, and solid mantle upwelling rates range from 10 to 30 cm/yr for tholeiites and from 0.1 to 1 cm/yr for basanites. Assuming a constant melt productivity, calculated total melt fractions range from 15% for the tholeiitic basalts to 3% for alkali basalts and basanites.

  4. Preparation of (228)Ra standard solution.

    PubMed

    Havelka, Miroslav

    2016-03-01

    For the preparation of a standard solution of (228)Ra, (228)Ra was isolated from (232)Th salt. Two simple methods were developed for Th-Ra separation. Both are based on a very good solubility of thorium nitrate in organic solvents. The first one used Ra co-precipitation with Pb in the form of Pb(NO3)2 from acetic acid solution. The second method was based on solvent extraction, remaining Th in the organic phase, while Ra was concentrated in the aqueous phase. The activity of (228)Ra (up to 20kBq) in the standard solution was related to the (232)Th standard by means of gamma ray spectrometry measurement. The obtained uncertainty was less than 0.7% (k=1). The standard solution was free of (232)Th and contained the carrier in the usual concentration (1gL(-1) BaCl2, 10gL(-1) HCl). Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Some Standard model problems and possible solutions

    NASA Astrophysics Data System (ADS)

    Barranco, J.

    2016-10-01

    Three problems of the standard model of elementary particles are studied from a phenomenological approach. (i) It is shown that the Dirac or the Majorana nature of the neutrino can be studied by looking for differences in the v-electron scattering if the polarization of the neutrino is considered. (ii) The absolute scale of the neutrino mass can be set if a four zero mass matrix texture is considered for the leptons. It is found that m ν3 ∼⃒ 0.05 eV. (iii) It is shown that it is possible -within a certain class of two Higgs model extensions of the standard model- to have a cancelation of the quadratic divergences to the mass of physical Higgs boson.

  6. Standardization of a 204Tl radioactive solution.

    PubMed

    Dias, Mauro S; Koskinas, Marina F

    2003-02-01

    The standardization of 204Tl is described. The efficiency tracing technique was applied using 134Cs as tracer. The 4(pi)beta-gamma coincidence system was used for the calibration. The (Laboratorio de Metrologia Nuclear) has participated in this comparison in collaboration with the Laboratório Nacional de Metrologia das Radiações Ionizantes, from Rio de Janeiro. Independent results using different techniques were developed by each of these laboratories and included in the comparison.

  7. Conformal Gravity Solutions to Standard Gravity Problems

    NASA Astrophysics Data System (ADS)

    O’Brien, James G.; Chaykov, Spasen; Chiarelli, Thomas L.; Saintable, Taylor; Harrington, Justin

    Gravitational theories outside standard general relativity have been drawing increased attention over the past several years, mostly due to the lack of direct observational evidence of dark matter. With some recent very high level dark matter searches continuing, and the parameter space to search decreasing has lead to a new interest in rethinking gravity at the largest of scales. As an alternative gravitational theory, conformal gravity has enjoyed much of the success of Modified Newtonian Dynamics (MOND) in predicting phenomenology, but differs dramatically in its initial construction. In this work, we explore some recent advances in conformal gravity, which help to build the case for support of such an alternative theory. Here, we highlight conformal gravity’s success in fitting new rotation curves, its ability to explain velocity dispersions in clusters, the initial steps towards gravitational lensing and finally, some preliminary work on explaining universal centripetal acceleration trends in galaxies.

  8. Common Workflow Service: Standards Based Solution for Managing Operational Processes

    NASA Astrophysics Data System (ADS)

    Tinio, A. W.; Hollins, G. A.

    2017-06-01

    The Common Workflow Service is a collaborative and standards-based solution for managing mission operations processes using techniques from the Business Process Management (BPM) discipline. This presentation describes the CWS and its benefits.

  9. A Method for Comparing Completely Standardized Solutions in Multiple Groups.

    ERIC Educational Resources Information Center

    Raykov, Tenko; Marcoulides, George A.

    2000-01-01

    Outlines a method for comparing completely standardized solutions in multiple groups. The method is based on a correlation structure analysis of equal-size samples and uses the correlation distribution theory implemented in the structural equation modeling program RAMONA. (SLD)

  10. Normal mode solutions of massless scalar field in standard cosmology.

    NASA Astrophysics Data System (ADS)

    Zecca, A.

    1999-06-01

    The generalized Klein-Gordon equation is reconsidered in the Robertson-Walker space-time. The separated time equation is integrated in the massless case by assuming the cosmological background of the standard cosmology. Normalized solutions are determined according to the requirement of a quantization procedure implemented by the Minkowski space.

  11. Interoperable and standard e-Health solution over Bluetooth.

    PubMed

    Martinez, I; Del Valle, P; Munoz, P; Trigo, J D; Escayola, J; Martínez-Espronceda, M; Muñoz, A; Serrano, L; Garcia, J

    2010-01-01

    The new paradigm of e-Health demands open sensors and middleware components that permit transparent integration and end-to-end interoperability of new personal health devices. The use of standards seems to be the internationally adopted way to solve these problems. This paper presents the implementation of an end-to-end standards-based e-Health solution. This includes ISO/IEEE11073 standard for the interoperability of the medical devices in the patient environment and EN13606 standard for the interoperable exchange of the Electronic Healthcare Record. The design strictly fulfills all the technical features of the most recent versions of both standards. The implemented prototype has been tested in a laboratory environment to demonstrate its feasibility for its further transfer to the healthcare system.

  12. Standard Electrode Potentials Involving Radicals in Aqueous Solution: Inorganic Radicals

    SciTech Connect

    Armstrong, David A.; Huie, Robert E.; Koppenol, Willem H.; Lymar, Sergei V.; Merenyi, Gabor; Neta, Pedatsur; Ruscic, Branko; Stanbury, David M.; Steenken, Steen; Wardman, Peter

    2015-12-01

    Recommendations are made for standard potentials involving select inorganic radicals in aqueous solution at 25 °C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. The recommended data are summarized in tables of standard potentials, Gibbs energies of formation, radical pKa’s, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations

  13. CTEPP STANDARD OPERATING PROCEDURE FOR PREPARATION OF SURROGATE RECOVERY STANDARD AND INTERNAL STANDARD SOLUTIONS FOR NEUTRAL TARGET ANALYTES (SOP-5.25)

    EPA Science Inventory

    This standard operating procedure describes the method used for preparing internal standard, surrogate recovery standard and calibration standard solutions for neutral analytes used for gas chromatography/mass spectrometry analysis.

  14. CTEPP STANDARD OPERATING PROCEDURE FOR PREPARATION OF SURROGATE RECOVERY STANDARD AND INTERNAL STANDARD SOLUTIONS FOR NEUTRAL TARGET ANALYTES (SOP-5.25)

    EPA Science Inventory

    This standard operating procedure describes the method used for preparing internal standard, surrogate recovery standard and calibration standard solutions for neutral analytes used for gas chromatography/mass spectrometry analysis.

  15. Rapid determination of 226Ra in environmental samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.

    2012-02-04

    A new rapid method for the determination of {sup 228}Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/ Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine {sup 228}Ra in solid samples (via {sup 228}Ac) , radiochemical methods that employ gas flow proportional counting techniques typically provide lower MDA (Minimal Detectable Activity) levels for the determination of {sup 228}Ra in water samples. Most radiochemical methods for {sup 228}Ra collect and purify {sup 228}Ra and allow for {sup 228}Ac daughter ingrowth for ~36 hours. In this new SRNL/EBL approach, {sup 228}Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 hours so that {sup 228}Ra assay results on water samples can be achieved in < 6 hours. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90%), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. {sup 228}Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify {sup 228}Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and {sup 90}Y. La is used to determine {sup 228}Ac chemical yield via ICP-MS, but {sup 133}Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

  16. Long-term stability of pure standards and stock standard solutions for the determination of pesticide residues using gas chromatography.

    PubMed

    Avramides, Elizabeth J

    2005-07-08

    The regular replacement of pure standards used in pesticide residue analysis laboratories and frequent preparation of stock standard solutions, both required by many accreditation bodies, impose considerable demands on a laboratory's resources. In this study, pure standards for all but one (heptenophos) of 118 different pesticides amenable to analysis by GC, and stock standard solutions (1000 microg/ml) prepared from these in toluene, acetone or ethyl acetate have been shown to be stable at < or = -20 degrees C over long periods: 4-13 and 2-8 years, respectively, for pure standards and solutions. Suitable solvents, containers and handling procedures are essential to avoid evaporation from solutions.

  17. Standardization of infusion solutions to reduce the risk of incompatibility.

    PubMed

    Nemec, Karin; Kopelent-Frank, Hannelore; Greif, Robert

    2008-09-01

    Although critically ill patients usually have various central intravenous (i.v.) lines, numerous drugs have to be infused simultaneously through the same lines. This can result in potentially harmful in-line incompatibility that can cause decreased drug effectiveness or increased microparticle load. To minimize the risk of these medication errors at an anesthesia intensive care unit (ICU), the preparation and administration of continuously infused drugs were standardized and the practicability in daily clinical routine was evaluated. The concentration and diluent of continuously administered i.v. drugs were standardized. The drugs were grouped according to pH, medical indication, and chemical structure. The ICU staff decided to use multilumen central venous catheters, and each group of drugs was assigned to one lumen. Only drugs that belonged to the same group were infused simultaneously through the same lumen; therefore, intragroup incompatibilities had to be excluded before establishing the new drug administration plan at the ICU. The visual compatibility of 115 clinically reasonable intragroup drug mixtures was investigated. All drug combinations were compatible for six hours except mixtures containing thiopental, which was reassigned to a single-line use. In the following year, the practicability of this drug administration plan was evaluated. No deviations were found in the compliance of the staff prescribing and preparing only standardized concentrations and diluents. Further research to investigate the chemical compatibility of the drugs in these multiple mixtures will follow. A project intended to avoid incompatibility among i.v. drugs infused in the intensive care setting included steps to standardize solutions and determine which could be given together.

  18. Proposed New Electrolytic Conductivity Primary Standards for KCl Solutions

    PubMed Central

    Wu, Y. C.; Koch, W. F.; Pratt, K. W.

    1991-01-01

    An absolute determination of aqueous electrolytic conductivity has been made for 0.01 molal (m) and 0.1 m potassium cliloride solutions, over the temperature range of 0 to 50 °C in 5 degree intervals. A cell with a removable center section of accurately known length and area was used for the measurements. Values were adjusted to be in conformity with the ITS-90 temperature scale. The overall uncertainty over the entire temperature range is estimated to be 0.03%. Values at 25 °C for 0.01 and 0.1 m are 0.00140823 and 0.0128246 S/cm, respectively. It is proposed that these values be adopted as primary standards for aqueous electrolytic conductivity, replacing the demal scale. PMID:28184109

  19. CTEPP STANDARD OPERATING PROCEDURE FOR PREPARATION OF SURROGATE RECOVERY STANDARD AND INTERNAL STANDARD SOLUTIONS FOR POLAR TARGET ANALYTES (SOP-5.26)

    EPA Science Inventory

    This SOP describes the method used for preparing surrogate recovery standard and internal standard solutions for the analysis of polar target analytes. It also describes the method for preparing calibration standard solutions for polar analytes used for gas chromatography/mass sp...

  20. CTEPP STANDARD OPERATING PROCEDURE FOR PREPARATION OF SURROGATE RECOVERY STANDARD AND INTERNAL STANDARD SOLUTIONS FOR POLAR TARGET ANALYTES (SOP-5.26)

    EPA Science Inventory

    This SOP describes the method used for preparing surrogate recovery standard and internal standard solutions for the analysis of polar target analytes. It also describes the method for preparing calibration standard solutions for polar analytes used for gas chromatography/mass sp...

  1. Mobile health requires mobile security: challenges, solutions, and standardization.

    PubMed

    Pharow, Peter; Blobel, Bernd

    2008-01-01

    Extended communication and advanced cooperation in a permanently growing healthcare and welfare domain require a well-defined set of security services provided by an interoperable security infrastructure based on international and European standards. Any communication and collaboration procedure requires a purpose. But such legal purpose-binding is definitely not the only aspect to carefully be observed and investigated. More and more, aspects of security, safety, privacy, ethics, and quality reach importance while discussing about future-proof health information systems and health networks - regardless whether local, regional or even pan-European networks. During the course of the current paradigm change from an organization-centered to a process-related and to a person-centered health system, different new technologies including mobile solutions need to be applied in order to meet challenges arising from both legal and technical circumstances. Beside the typical Information and Communication Technology systems and applications, the extended use of modern technologies includes large medical devices like, e.g., MRI and CT but also small devices like sensors worn by a person or included in clothing. Security and safety are on top of the priority list. The paper addresses the identification of some specific aspects like mobile technology and safety when moving both IT and people towards mobile health aiming at increasing citizens and patients awareness, confidence, and acceptance in future mobile care - a world often still beyond the horizon.

  2. Implementing High Standards in Urban Schools: Problems and Solutions.

    ERIC Educational Resources Information Center

    Lee, James O.

    2003-01-01

    Compares "associationist" instructional theory and standards with constructivist instructional theory and standards. Argues that constructivist standards should be used to help create a culture of high quality based on high expectations in urban schools. Provides two examples: Central Park East Secondary School (CPESS) and the Philadelphia's…

  3. [Reference standards in diagnostic research: problems and solutions].

    PubMed

    de Groot, Joris A H; Reitsma, Johannes B; Moons, Karel G M

    2014-01-01

    The accuracy of diagnostic tests is of utmost importance as biased test results may lead to wrong decisions in clinical practice. In diagnostic accuracy research the results of a diagnostic test, model or strategy are compared to those of the reference standard, i.e. the best available method to determine whether a certain condition or disease is present or absent. Problems with the reference standard lead to biased test results. The umbrella term for this is 'verification bias'. Verification bias arises if the reference standard cannot be applied to all patients, if investigators use different reference standards or simply because there is no reference standard. Correction of these problems is often possible, and, if it is applied in a transparent and reproducible fashion it will deliver useful diagnostic information. Clinicians who use a diagnostic test should take possible verification bias into account.

  4. [Pediatric parenteral nutrition: are standard solutions better than individualized ones?].

    PubMed

    Moreno Villares, J M; Fernández-Shaw, C; Gomis Muñoz, P; Valero Zanuy, M A; León Sanz, M

    2002-07-01

    Pediatric parenteral nutrition (PN) in Spain has traditionally been prescribed and made up on an individual basis. This practice entails daily indication of the quantity of each of the components of the PN bag as well as precise calculations for its formulation and preparation. The main advantages of individualized prescriptions are their flexibility and precise biochemical control. The aim of this study was to determine whether pediatric PN can be standardized in a tertiary care hospital. We reviewed the composition of all the pediatric PN bags prepared in our hospital from 1.1.1996 to 31.12.1998. Each individual prescription was compared with a standard PN fulfilling the following criteria: a) Holiday-Segar equation for volume; b) 1 kcal/ml (10 %), and c) macronutrient distribution: 8-15 % amino acids, 55-65 % dextrose; 30-35 % lipids. The results of this comparison were used to estimate the number of bags fulfilling all three criteria and those that fulfilled only the third. We also reviewed the distribution of PN bags prepared according to the protocol used in our center which allows three options: standard PN, individualized prescription, and individualized prescription except electrolytes, supplied in fixed concentrations per liter of PN. Five hundred fifty-four patients received 7,921 PN bags. The mean duration of PN was 14.3 days and the mean number of PN per day was 7.2. Only 4.5 % fulfilled all three criteria but 16.2 % satisfied at least the last criterion. If the three criteria for standardization were applied, only one PN bag/day could be prepared. Analysis of the application of our protocol revealed that of all the PN bags prepared only 27.9 % were partially or totally standardized. However, exclusion of neonates increased this figure to 53.2 %. If rigid standardization criteria are applied, only a small number of PN bags can be prepared in a tertiary hospital. Combining both standard and tailored PN could reduce pharmacy workload and costs while

  5. Standard enthalpies of formation for glycyl-tyrosine and products of its dissociation in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Kochergina, L. A.; Badelin, V. G.; Krutova, O. N.; Volkov, A. V.; Damrina, K. V.

    2015-07-01

    The enthalpies of solution of crystalline glycyl-tyrosine in water and potassium hydroxide aqueous solutions are determined at 298.15 K by means of direct calorimetry. Standard enthalpies of formation for dipeptide and its products of dissociation in an aqueous solution are calculated.

  6. The standard enthalpies of formation of crystalline N-(carboxymethyl)aspartic acid and its aqueous solutions

    NASA Astrophysics Data System (ADS)

    Lytkin, A. I.; Chernyavskaya, N. V.; Volkov, A. V.; Nikol'Skii, V. M.

    2007-07-01

    The energy of combustion of N-(carboxymethyl)aspartic acid (CMAA) was determined by bomb calorimetry in oxygen. The standard enthalpies of combustion and formation of crystalline N-(carboxymethyl)aspartic acid were calculated. The heat effects of solution of crystalline CMAA in water and a solution of sodium hydroxide were measured at 298.15 K by direct calorimetry. The standard enthalpies of formation of CMAA and its dissociation products in aqueous solution were determined.

  7. Soil processes and chemical transport

    SciTech Connect

    Rutherford, P.M.; Dudas, M.J.; Arocena, J.M.

    1995-03-01

    Phosphogypsum (PG) is an acidic by-product of the phosphate fertilizer industry, and is produced in large quantities by the wet phosphoric acid process. Most PG is sluiced out to repositories, forming large stockpiles. Phosphogypsum is composed mainly of gypsum (Ca-SO{sub 4}{center_dot}2H{sub 2}O), but contains impurities of environmental concern such as F{sup -}, acids, trace elements, and naturally occurring radionuclides, which originate from the phosphate rock used in processing. Possible movement of these impurities into groundwater is an issue. {sup 226}Radium is the major source of radioactivity in PG produced from sedimentary phosphate rock. Few studies have addressed the leachability of {sup 226}Ra because solid solutions of Ra, Ba, and Sr are very insoluble. The objective of this study was to investigate the concentrations of {sup 226}Ra, Ba and Sr in leachate generated from PG produced from Togo phosphate rock. Phosphogypsum was extracted 30 times with deionized distilled (d.d.) H{sub 2}O over 30 d. Extractable {sup 226}Ra was maximal (0.55 Bq L{sup -1}) and Day 30 Minimum extractable {sup 226}RA (0.23 Bq L{sup -1}) occurred on the Day 30 extraction but still exceeded the current U.S. drinking water standard. Solid phase {sup 226}Ra increased between Day 0 (850 Bq kg{sup -1}) and DAy 30 (1120 Bq kg{sup -1}). The {sup 226}Ra/Ba ratios in the solid phase and in the extractable liquid phase very nearly equal over the last half of the extraction period. If this relationship holds for other PGs, then solution {sup 226}Ra activities can be estimated if solid-phase {sup 226}Ra/Ba ratios are known and Ba solution concentrations are known or estimated. 38 refs., 3 figs., 3 tabs.

  8. Copper leaching from brake wear debris in standard extraction solutions.

    PubMed

    Hur, Jin; Yim, Soobin; Schlautman, Mark A

    2003-10-01

    Quantification of the copper content of and copper leaching from a disc brake wear debris sample was performed using microwave-assisted acid digestion, the Federal Toxicity Characteristic Leaching Procedure (TCLP), and the State of California Waste Extraction Test (WET). The brake wear debris tested was a composite sample obtained from a brake dynamometer test of one brake pad source material. Comparative digestion studies demonstrated that a modified aqua regia matrix (HNO3:HCl:H2O2 = 1:3:0.5) optimized the digestion effectiveness for determining the total copper content in the brake wear debris. No significant sample heterogeneity within the brake wear debris was observed, based on statistically indistinguishable total copper content results for subsamples with a wide range of sample masses. Upon pooling all subsample results, an overall total copper content for the composite brake wear debris sample was determined to be 10.8% (g/g), with a 95% confidence limit of +/- 0.5% (g/g). Copper leaching increased with decreasing solid-to-liquid ratios in TCLP tests, but was unaffected by the solid-to-liquid ratio in the WET. For a 1:10(4) (g/g) solid-to-liquid ratio, 85% and 99% of the total mass of copper present in the composite brake wear debris sample was leached into solution during the TCLP and WET, respectively. Rate studies also demonstrated that the WET resulted in a faster rate and higher extent of copper leaching relative to the TCLP. Compared to reference copper-containing materials, the composite brake wear debris sample exhibited relatively higher TCLP and WET copper leaching characteristics. The higher copper leaching exhibited by the brake wear debris sample may have resulted from its higher specific surface area and/or from changes in the chemical form of copper that occurred during the braking process.

  9. Deployment of Porous Crystalline Matrix (Gubka) Technology for Stabilizing Radioactive Standard Solutions at Fernald

    SciTech Connect

    Knecht, D. A.; Tranter, T. J.; Macheret, J.; Meyer, A.; Yesso, D.; Daniels, T.; Aloy, A. S.; Sapozhnikova, N. V.; Anshits, A. G.; Sharonova, O. M.; Tretyakov, A. A.

    2002-02-26

    Radioactive solutions requiring stabilization exist in various compositions throughout the DOE complex. Future cleanup could generate additional actinide residue solutions requiring stabilization at facilities where processing capabilities have been dismantled. Radiological laboratory standard solutions (liquid technical standards) have recently been identified at the Fernald site, which require stabilization and disposal before the laboratory facilities at Fernald can be decommissioned. The Fernald solutions consist of approximately 25 liters of acidic solutions containing isotopes of Cs, Ba, Ra, Eu, U, Am, Po, Ru, Sr, Th, Pb, Pu, and Np and in some cases small quantities of added salts. After stabilization and waste acceptance approval, the resulting waste forms will be disposed at the Nevada Test Site. This paper describes the technology and progress in using the Russian ''Gubka'' technology to stabilize the Fernald liquid technical standards for disposal by September 2002 to meet the facility D&D schedule.

  10. Fluorescent rare earth solutions as intrinsic wavelength standards for protein fluorescence spectroscopy.

    PubMed

    Anderle, Heinz; Weber, Alfred

    2017-02-01

    Trivalent Gd, Tm, and Dy solutions can be used as intrinsic excitation and emission standards to validate the UV and violet-blue wavelength accuracy of a spectrofluorimeter. Europium extends the range into the red. To attain sufficient sensitivity, these luminescent rare earth ions require deuterated reagents or carbonate complexation, which allow the use of ordinary water and thus preparation in virtually any laboratory. Such solutions are particularly valuable as system suitability standards (SST) for protein fluorescence spectroscopy to detect red shifts of the intrinsic fluorescence maximum in stability and storage studies.

  11. 78 FR 14773 - U.S. Environmental Solutions Toolkit-Landfill Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ... environmental technologies that will outline U.S. approaches to a series of environmental problems and highlight... Toolkit will refer users in foreign markets to U.S. approaches to solving environmental problems and to U... International Trade Administration U.S. Environmental Solutions Toolkit--Landfill Standards AGENCY...

  12. Development of an Ultra-Pure, Carrier-Free 209Po Solution Standard

    PubMed Central

    Collé, R.; Fitzgerald, R. P.; Laureano-Perez, L.

    2015-01-01

    Ultra-pure, carrier-free 209Po solution standards have been prepared and standardized for their massic alpha-particle emission rate. The standards, which will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4326a, have a mean mass of (5.169 ± 0.003) g of a solution of polonium in nominal 2.0 mol▪L−1 HCl (having a solution density of (1.032 ± 0.002) g▪ mL−1 at 20 °C) that are contained in 5 mL, flame-sealed, borosilicate glass ampoules. They are certified to contain a 209Po massic alpha-particle emission rate of (39.01 ± 0.18) s−1▪g−1 as of a reference time of 1200 EST, 01 December 2013. This new standard series replaces SRM 4326 that was issued by NIST in 1994. The standardization was based on 4πα liquid scintillation (LS) spectrometry with two different LS counting systems and under wide variations in measurement and counting source conditions. The methodology for the standardization, with corrections for detection of the low-energy conversion electrons from the delayed 2 keV isomeric state in 205Pb and for the radiations accompanying the small 0.45 % electron-capture branch to 209Bi, involves a unique spectral analysis procedure that is specific for the case of 209Po decay. The entire measurement protocol is similar, but revised and improved from that used for SRM 4326. Spectroscopic impurity analyses revealed that no photon-emitting or alpha-emitting radionuclidic impurities were detected. The most common impurity associated with 209Po is 208Po and the activity ratio of 208Po/209Po was < 10−7. PMID:26958444

  13. Long-term stability of carrier-added Ge-68 standardized solutions

    PubMed Central

    Zimmerman, B. E.; Bergeron, D. E.; Fitzgerald, R.; Cessna, J. T.

    2016-01-01

    Tests for chemical stability were carried out on carrier-added 68Ge solutions prepared and calibrated in 2007 and 2011 to evaluate the suitability of the specific composition as a potential Standard Reference Material. Massic count rates of the stored solutions were measured using a NaI(Tl) well counter before and after gravimetric transfers. The present activity concentration of the 2007 solution was also measured using live-timed anticoincidence counting (LTAC) and compared to the 2007 calibrated value. The well counter data indicated no change in massic count rate to within uncertainties for either solution. The LTAC measurements gave a difference of −0.49 % in the activity concentration 2007 solution over 7 years. However, the uncertainty in the decay correction over that time, due to the uncertainty in the 68Ge half-life, accounted for the majority (0.67 % out of 0.83 %) of the standard uncertainty on the activity concentration. The results indicate that these carrier-added solutions are stable with regard to potential activity losses over several half-lives of 68Ge. PMID:26671789

  14. DEPLOYMENT OF THE GUBKA TECHNOLOGY TO STABILIZE RADIOACTIVE STANDARD SOLUTIONS AT THE FERNALD ENVIRONMENTAL MANAGEMENT PROJECT

    SciTech Connect

    Chipman, N.A.; Knecht, D.A.; Meyer, A.; Aloy, A.; Anshits, A.G.; Tretyakov, A.A.

    2003-02-27

    This paper describes the deployment of the Gubka technology to stabilize liquid technical standards at the Fernald Environmental Management Project. Gubka, an open-cell glass crystalline porous material, was developed by a joint research program of Russian Institutes at St. Petersburg, Krasnoyarsk, and Zheleznogorsk and the Idaho National Engineering and Environmental Laboratory. Gubka technology can be applied in an active or a passive method to stabilize a solution. In both methods the result is the same, and the dried components of the solution are sorbed in the pores of the Gubka block while the liquid phase is evaporated. In this deployment Gubka blocks were passively floated in the solutions at ambient conditions. As the solutions evaporated, the non-volatile components were sorbed in the pores of the Gubka blocks. The waste-loaded Gubka blocks have been packaged for transportation and disposal at the Nevada Test site within an existing waste category.

  15. Process for the removal of radium from acidic solutions containing same

    DOEpatents

    Scheitlin, F.M.

    The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of /sup 226/Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

  16. Removal of radium from acidic solutions containing same by adsorption on coal fly ash

    DOEpatents

    Scheitlin, Frank M.

    1984-01-01

    The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of .sup.226 Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

  17. Preparation of ASTER in-house 10Be/9Be standard solutions

    NASA Astrophysics Data System (ADS)

    Braucher, R.; Guillou, V.; Bourlès, D. L.; Arnold, M.; Aumaître, G.; Keddadouche, K.; Nottoli, E.

    2015-10-01

    Since its commissioning in 2006, the commercially available certificated National Institute of Standards and Technology standard reference material NIST SRM 4325 is used at the French national facility ASTER (CEREGE, Aix-en-Provence) to normalize 10Be measurements. This standard solution being no longer disposable, we thus decided to produce in-house standards. As a first attempt, a STD-12 standard (10Be/9Be = (4.939 ± 0.053) × 10-12) has been prepared from 2.5 kg of marine sediments with an adapted chemical protocol. Then, a 10Be enriched solution of known concentration being available, a STD-11 standard (10Be/9Be = (1.191 ± 0.013) × 10-11) that will be used at ASTER in the near future to calibrate 10Be measurements and its dilution to the 10-14 level (STD-14 (10Be/9Be = (5.468 ± 0.064) × 10-14)) have been prepared from it.

  18. Development of a primary standard for absorbed dose from unsealed radionuclide solutions

    NASA Astrophysics Data System (ADS)

    Billas, I.; Shipley, D.; Galer, S.; Bass, G.; Sander, T.; Fenwick, A.; Smyth, V.

    2016-12-01

    Currently, the determination of the internal absorbed dose to tissue from an administered radionuclide solution relies on Monte Carlo (MC) calculations based on published nuclear decay data, such as emission probabilities and energies. In order to validate these methods with measurements, it is necessary to achieve the required traceability of the internal absorbed dose measurements of a radionuclide solution to a primary standard of absorbed dose. The purpose of this work was to develop a suitable primary standard. A comparison between measurements and calculations of absorbed dose allows the validation of the internal radiation dose assessment methods. The absorbed dose from an yttrium-90 chloride (90YCl) solution was measured with an extrapolation chamber. A phantom was developed at the National Physical Laboratory (NPL), the UK’s National Measurement Institute, to position the extrapolation chamber as closely as possible to the surface of the solution. The performance of the extrapolation chamber was characterised and a full uncertainty budget for the absorbed dose determination was obtained. Absorbed dose to air in the collecting volume of the chamber was converted to absorbed dose at the centre of the radionuclide solution by applying a MC calculated correction factor. This allowed a direct comparison of the analytically calculated and experimentally determined absorbed dose of an 90YCl solution. The relative standard uncertainty in the measurement of absorbed dose at the centre of an 90YCl solution with the extrapolation chamber was found to be 1.6% (k  =  1). The calculated 90Y absorbed doses from published medical internal radiation dose (MIRD) and radiation dose assessment resource (RADAR) data agreed with measurements to within 1.5% and 1.4%, respectively. This study has shown that it is feasible to use an extrapolation chamber for performing primary standard absorbed dose measurements of an unsealed radionuclide solution. Internal radiation

  19. Assessment of NER solutions against the first and second CALBC Silver Standard Corpus.

    PubMed

    Rebholz-Schuhmann, Dietrich; Jimeno Yepes, Antonio; Li, Chen; Kafkas, Senay; Lewin, Ian; Kang, Ning; Corbett, Peter; Milward, David; Buyko, Ekaterina; Beisswanger, Elena; Hornbostel, Kerstin; Kouznetsov, Alexandre; Witte, René; Laurila, Jonas B; Baker, Christopher Jo; Kuo, Cheng-Ju; Clematide, Simone; Rinaldi, Fabio; Farkas, Richárd; Móra, György; Hara, Kazuo; Furlong, Laura I; Rautschka, Michael; Neves, Mariana Lara; Pascual-Montano, Alberto; Wei, Qi; Collier, Nigel; Chowdhury, Md Faisal Mahbub; Lavelli, Alberto; Berlanga, Rafael; Morante, Roser; Van Asch, Vincent; Daelemans, Walter; Marina, José Luís; van Mulligen, Erik; Kors, Jan; Hahn, Udo

    2011-10-06

    Competitions in text mining have been used to measure the performance of automatic text processing solutions against a manually annotated gold standard corpus (GSC). The preparation of the GSC is time-consuming and costly and the final corpus consists at the most of a few thousand documents annotated with a limited set of semantic groups. To overcome these shortcomings, the CALBC project partners (PPs) have produced a large-scale annotated biomedical corpus with four different semantic groups through the harmonisation of annotations from automatic text mining solutions, the first version of the Silver Standard Corpus (SSC-I). The four semantic groups are chemical entities and drugs (CHED), genes and proteins (PRGE), diseases and disorders (DISO) and species (SPE). This corpus has been used for the First CALBC Challenge asking the participants to annotate the corpus with their text processing solutions. All four PPs from the CALBC project and in addition, 12 challenge participants (CPs) contributed annotated data sets for an evaluation against the SSC-I. CPs could ignore the training data and deliver the annotations from their genuine annotation system, or could train a machine-learning approach on the provided pre-annotated data. In general, the performances of the annotation solutions were lower for entities from the categories CHED and PRGE in comparison to the identification of entities categorized as DISO and SPE. The best performance over all semantic groups were achieved from two annotation solutions that have been trained on the SSC-I.The data sets from participants were used to generate the harmonised Silver Standard Corpus II (SSC-II), if the participant did not make use of the annotated data set from the SSC-I for training purposes. The performances of the participants' solutions were again measured against the SSC-II. The performances of the annotation solutions showed again better results for DISO and SPE in comparison to CHED and PRGE. The SSC

  20. Standard electrode potentials involving radicals in aqueous solution: inorganic radicals (IUPAC Technical Report)

    DOE PAGES

    Armstrong, David A.; Huie, Robert E.; Koppenol, Willem H.; ...

    2015-01-01

    We made recommendations for standard potentials involving select inorganic radicals in aqueous solution at 25 °C. These recommendations are based on a critical and thorough literature review and also by performing derivations from various literature reports. We also summarized the data in tables of standard potentials, Gibbs energies of formation, radical pKa’s, and hemicolligation equilibrium constants. In all cases, current best estimates of the uncertainties are provided. An extensive set of Data Sheets is appended that provide original literature references, summarize the experimental results, and describe the decisions and procedures leading to each of the recommendations.

  1. Standard thermodynamic functions of complex formation between Cu2+ and glycine in aqueous solution

    NASA Astrophysics Data System (ADS)

    Gorboletova, G. G.; Metlin, A. A.

    2013-05-01

    Heat effects of the interaction of copper(II) solutions with aminoacetic acid (glycine) are measured by the direct calorimetry at 298.15 K and ionic strengths of 0.5, 1.0, and 1.5 against a background of potassium nitrate. Standard enthalpy values for reactions of the formation of aminoacetic acid copper complexes in aqueous solutions are obtained using an equation with a single individual parameter by extrapolating it to zero ionic strength. The standard thermodynamic characteristics of complex formation in the Cu2+-glycine system are calculated. It is shown that glycine-like coordination is most likely in Cu(II) complexes with L-asparagine, L-glutamine, and L-valine.

  2. Multicomponent leach tests in Standard Canadian Shield Saline Solution on glasses containing simulated nuclear waste

    SciTech Connect

    Heimann, R.B.; Wood, D.D.; Hamon, R.F.

    1984-01-01

    Leaching experiments on borosilicate glass frit and simulated nuclear waste glasses were performed as a preliminary to leaching experiments on glasses incorporating radioactive waste. The experimental design included (1) simulated waste glass, (2) ASTM Grade-2 titanium container material, (3) clay buffer material, (4) Standard Canadian Shield Saline Solution, and (5) granitic rock. Cumulative fractions of release for boron were determined, as well as the solution concentrations of silicon, iron, strontium and cesium. The leach rates for boron after 28 d were approximately 5 x 10/sup -6/ kg x m/sup -2/ x s/sup -1/ in Hastelloy vessels. There is an apparently strong relationship between the clay/groundwater ratio, the concentration of iron in the solution, and the concentrations of silicon, strontium, and cesium.

  3. Peritoneal clearance of homocysteine with icodextrin or standard glucose solution exchange.

    PubMed

    Czupryniak, Aneta; Nowicki, Michal; Chwatko, Grazyna; Jander, Anna; Bald, Edward

    2005-12-01

    The aim of the study was to assess plasma homocysteine concentration in peritoneal dialysis patients, and to compare the effect of different peritoneal solutions (glucose-based and icodextrin-based) on peritoneal clearance of homocysteine. The study group comprised 10 chronic peritoneal dialysis patients; the control group comprised 15 healthy, age-matched non-obese subjects with normal renal function. Patients with vitamin B(12) or folate deficiency were excluded. In all subjects, plasma homocysteine and dialysis adequacy parameters were assessed at baseline. The clearance study was carried out with 2.27% glucose and 7.5% icodextrin solutions (12-h dwell time). Mean dialysate concentration of homocysteine was similar for both glucose and icodextrin solutions (8.3 +/- 3.2 and 8.4 +/- 1.9 micromol/L, respectively), but homocysteine clearance was significantly higher for icodextrin than glucose solution (1.82 +/- 0.57 vs 1.39 +/- 0.53 mL/min per 1.73 m(2)P = 0.01). Net ultrafiltration after icodextrin solution was also higher than after glucose solution (599 +/- 136 mL vs 134 +/- 337 mL, P < 0.01). A correlation between total plasma level of homocysteine and its peritoneal clearance was found (r = 0.69; P = 0.03). It appears that peritoneal elimination of homocysteine depends primarily on its plasma concentration. Icodextrin-based solution for peritoneal dialysis seems to be more efficient in homocysteine elimination than a standard glucose-based solution.

  4. Economic evaluation of neutral-pH, low-glucose degradation product peritoneal dialysis solutions compared with standard solutions: a secondary analysis of the balANZ Trial.

    PubMed

    Howard, Kirsten; Hayes, Alison; Cho, Yeoungjee; Cass, Alan; Clarke, Margaret; Johnson, David W

    2015-05-01

    Biocompatible solutions may lower peritonitis rates, but are more costly than conventional solutions. The aim of the present study was to assess the additional costs and health outcomes of biocompatible over conventional solutions in incident peritoneal dialysis patients to guide practice decisions. Secondary economic evaluation of a randomized controlled trial. 185 participants in the balANZ trial. Cost-effectiveness of biocompatible compared to standard solution over the 2 years using an Australian health care funder perspective. Intervention group received biocompatible solutions and control group received standard solutions over 2 years. Costs included dialysis charges, costs of treating peritonitis, non-peritonitis-related hospital stays, and medication. Peritonitis was the health outcome of interest; incremental cost-effectiveness ratios were reported in terms of the additional cost per additional patient avoiding peritonitis at 2 years. Mean total per-patient costs were A$57,451 and A$53,930 for the biocompatible and standard-solution groups, respectively. The base-case analysis indicated an incremental cost of A$17,804 per additional patient avoiding peritonitis at 2 years for biocompatible compared to standard solution. In a sensitivity analysis excluding extreme outliers for non-peritonitis-related hospitalizations, mean per-patient costs were A$49,159 and A$52,009 for the biocompatible and standard-solution groups, respectively. Consequently, the incremental cost-effectiveness ratio also was reduced significantly: biocompatible solution became both less costly and more effective than standard solution and, in economic terms, was dominant over standard solution. Peritonitis was a secondary outcome of the balANZ trial. Health outcomes measured only in terms of patients avoiding peritonitis over 2 years may underestimate the longer term benefits (eg, prolonged technique survival). Biocompatible dialysis solutions may offer a cost-effective alternative to

  5. Efficacy of mung bean (lentil) and pop rice based rehydration solutions in comparison with the standard glucose electrolyte solution.

    PubMed

    Bhan, M K; Ghai, O P; Khoshoo, V; Vasudev, A S; Bhatnagar, S; Arora, N K; Rashmi; Stintzing, G

    1987-01-01

    Children with acute diarrhea and moderate dehydration between 3 months and 5 years of age were randomly assigned to receive treatment with standard WHO oral rehydration solution (ORS) (n = 33) and two other solutions in which the 20 g/L glucose was substituted by 50 g/L of pop rice (n = 31) and 60 g/L of mung bean (lentil) powder (n = 29). Satisfactory oral rehydration, as assessed clinically and by changes in PCV and total serum solids (TSS), was achieved in 90.9% with WHO ORS, 96.8% with pop rice, and 96.6% in the mung bean ORS treated group (p greater than 0.05). The purging rates (ml/kg/h) until recovery were 2.49 +/- 1.5 (pop rice); 2.91 +/- 2.0 (WHO), and 3.41 +/- 1.7 in the mung bean group (p greater than 0.05). The percentage of patients recovering from diarrhea within the 72 h study period was 58.0 (pop rice), 48.4 (WHO), and 44.8 for mung bean group (p greater than 0.05). Though differences in stool volumes and duration in the three groups were not statistically different, there was a trend toward improvement in efficacy with the pop rice ORS in several parameters: greater weight gain, higher percentage decline in TSS, higher urine output despite lower ORS intake, and lower purging rates. The intake of semisolids in the 24-72 h study period was also higher in the pop rice group as compared to the other two groups (p less than 0.05). The number of breast feeds and intake of artificial milk was however similar in all groups (p greater than 0.05).

  6. Comparison of laboratories directors' and assessors' opinions on challenges and solutions of standardization in Iran: a qualitative study.

    PubMed

    Ravaghi, Hamid; Abolhassani, Nazanin

    2015-01-26

    The quality medical laboratory services play a vital role in healthcare systems. Iran has set national standards based on the international standard ISO15189. These standards came into force in September 2007. Given the important role of both laboratories professional and assessors in the standardization, this study aims to compare and analyze medical laboratory directors' and assessors' opinions about this process, its challenges and relevant solutions. This qualitative study was conducted on two populations in 2013. The first survey population consisted of 150 assessors. The second group consisted of directors working in medical laboratory settings. From all universities of medical sciences, 258 medical laboratories were randomly selected. Data were gathered using two open-ended questionnaires and analyzed using the thematic analysis. Challenges and relevant solutions regarding the standardization and standards, the assessment process and assessor, laboratories, external entities and contextual factors across laboratories directors and assessors were derived and compared. Both groups had a positive attitude towards the standardization process. However, they expressed some concerns regarding the process and accordingly proposed solutions to overcome the challenges. This study provides insights into the challenges and solutions of the standardization from two professional groups' viewpoint. These two factors are closely related and should be considered when implementing standards since a positive perception of them increases the likelihood of successful standardization. Similarities and divergences regarding challenges and solutions of the standardization, in turn, can provide insights into how this process can be improved and deserve policy makers' attention to continue the progress.

  7. Comparison of Laboratories Directors’ and Assessors’ Opinions on Challenges and Solutions of Standardization in Iran: A Qualitative Study

    PubMed Central

    Ravaghi, Hamid; Abolhassani, Nazanin

    2015-01-01

    Objective: The quality medical laboratory services play a vital role in healthcare systems. Iran has set national standards based on the international standard ISO15189. These standards came into force in September 2007. Given the important role of both laboratories professional and assessors in the standardization, this study aims to compare and analyze medical laboratory directors’ and assessors’ opinions about this process, its challenges and relevant solutions. Methods: This qualitative study was conducted on two populations in 2013. The first survey population consisted of 150 assessors. The second group consisted of directors working in medical laboratory settings. From all universities of medical sciences, 258 medical laboratories were randomly selected. Data were gathered using two open-ended questionnaires and analyzed using the thematic analysis. Results: Challenges and relevant solutions regarding the standardization and standards, the assessment process and assessor, laboratories, external entities and contextual factors across laboratories directors and assessors were derived and compared. Both groups had a positive attitude towards the standardization process. However, they expressed some concerns regarding the process and accordingly proposed solutions to overcome the challenges. Conclusion: This study provides insights into the challenges and solutions of the standardization from two professional groups’ viewpoint. These two factors are closely related and should be considered when implementing standards since a positive perception of them increases the likelihood of successful standardization. Similarities and divergences regarding challenges and solutions of the standardization, in turn, can provide insights into how this process can be improved and deserve policy makers’ attention to continue the progress. PMID:25946940

  8. The enthalpies of solution of VOCl3 in dilute solutions of sodium hydroxide and the standard enthalpy of formation of liquid VOCl3

    NASA Astrophysics Data System (ADS)

    Dmitrieva, N. G.; Romodanovskii, P. A.; Gridchin, S. N.; Vorob'ev, P. N.

    2010-01-01

    The enthalpies of solution of liquid vanadium oxytrichloride in dilute solutions of sodium hydroxide were determined by direct calorimetric measurements at 298.15 K and ionic strength values I = 0.3, 0.5, and 1.0 (NaClO4). The experimental data were used to calculate the standard enthalpy of formation of liquid VOCl3.

  9. Enthalpy of solution of VOCl3 in dilute sodium hydroxide solutions and the standard enthalpy of formation of the HVO{4/2-} ion

    NASA Astrophysics Data System (ADS)

    Romodanovskii, P. A.; Vorob'ev, P. N.; Dmitrieva, N. G.; Gridchin, S. N.

    2007-12-01

    The calorimetric enthalpies of solution of liquid vanadium oxytrichloride in dilute sodium hydroxide solutions were measured at 298.15 K and ionic strengths I = 0.5, 1.0, or 1.5 (NaClO4). The standard enthalpy of formation of the HVO{4/2-} ion was calculated from the measured data.

  10. Standard thermodynamic functions of Co2+ complexation with glycine and L-histidine in aqueous solution

    NASA Astrophysics Data System (ADS)

    Gorboletova, G. G.; Metlin, A. A.

    2016-02-01

    The enthalpies of the reactions between solutions of Co(NO3)2 and solutions of glycine (Gly) and L-histidine (His) are determined via direct calorimetry at different pH values and metal: ligand ratios using KNO3 as a background electrolyte ( T = 298.15 K, I = 0.2-1.0). The enthalpy changes upon the formation of cobalt glycinate complexes and Co2+ mixed-ligand complex, viz., glycine-L-histidine, were calculated. The standard thermodynamic parameters (Δr H°, Δr G°, Δr S°) of complexation are determined. The CoGlyHis complex is shown to be stable toward decomposition into homogeneous complexes.

  11. Hyperosmolar irrigation compared with a standard solution in a canine shoulder arthroscopy model.

    PubMed

    Capito, Nicholas M; Smith, Matthew J; Stoker, Aaron M; Werner, Nikki; Cook, James L

    2015-08-01

    A hyperosmolar irrigation solution may decrease fluid extravasation during arthroscopic procedures. Demonstrating the safety of a hyperosmolar irrigation solution with respect to chondrocyte viability and cartilage water content was deemed necessary before designing a clinical efficacy study. We designed a translational animal model study in which hyperosmolar arthroscopy irrigation fluid (1.8%, 600 mOsm/L) was compared with normal saline (0.9%, 300 mOsm/L). Purpose-bred research dogs (n = 5) underwent bilateral shoulder arthroscopy. Irrigation fluid was delivered to each shoulder joint (n = 10) at 40 mm Hg for 120 minutes using standard ingress and egress portals. The percentage change in shoulder girth was documented at the completion of 120 minutes. Articular cartilage sections from the glenoid and humeral head were harvested from both shoulders. Chondrocyte viability and tissue water content were evaluated. Differences between groups and compared with time 0 controls were determined, with significance set at P <.05. The mean percentage change in shoulder girth was higher in the isotonic control group (13.3%) than in the hyperosmolar group (10.4%). Chondrocyte viability and tissue water content for glenoid and humeral head cartilage were well maintained in both treatment groups, and differences were not statistically significant. The data from this study suggest that doubling the osmolarity of the standard irrigation solution used for arthroscopy was not associated with any detrimental effects on chondrocyte viability or tissue water content after 2 hours of arthroscopic irrigation. On the basis of potential benefits in conjunction with the safety demonstrated in these data, clinical evaluation of a hyperosmolar solution for irrigation during shoulder arthroscopy appears warranted. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  12. Automatic determination of chlorine without standard solutions using a biamperometric flow-batch analysis system.

    PubMed

    Nascimento, Valberes B; Selva, Thiago M G; Coelho, Elaine C S; Santos, Francyana P; Antônio, Jadielson L S; Silva, José R; Gaião, Edvaldo N; Araújo, Mário C U

    2010-04-15

    This study presents an automatic analysis system that does not require the use of standard solutions. The system uses an electrochemical flow cell for in line generation of the standards, and operates under the standard addition technique. The versatility of this system was demonstrated by the development of a one key touch fully automatic method for the determination of total available chlorine in real samples. The extremely simple, accurate and inexpensive method was based simply on the biamperometric monitoring of the well known redox reaction of chlorine with iodide ions in a flow-batch system, where the produced iodine (triiodide ions) generates an electrical current proportional to the chlorine concentration in the sample. The flow-batch parameters were optimized to maximize the sensitivity without losses on the precision of the analysis. An excellent linear dependence between the biamperometric signal and the chlorine concentration for the standard additions and a good agreement between the proposed approach and a reference method were obtained. The method was successfully applied to determine chlorine in several different bleach and chlorinated water samples (r=0.9995, LOD=8.261 x 10(-7) mol L(-1)) and could be easily extended to other oxidants and samples. Comparison to a reference method and recoveries close to 100% demonstrated the reliability of the proposed method. In addition, low residue disposal and reagent consumption, allied with high accuracy and precision, make it very promising for routine applications.

  13. Aseptic peritonitis due to peptidoglycan contamination of pharmacopoeia standard dialysis solution.

    PubMed

    Martis, Leo; Patel, Mehul; Giertych, Joe; Mongoven, Jim; Taminne, Michel; Perrier, Michele A; Mendoza, Omar; Goud, Niranjan; Costigan, Aidan; Denjoy, Nicole; Verger, Christian; Owen, William F

    Manufacturers of parenteral solutions adhere to European and US Pharmacopoeia standards to define safety and sterility. In response to excess cases of aseptic peritonitis in peritoneal dialysis patients using icodextrin-containing dialysate that met all pharmacopoeia standards, a global recall was issued in May, 2002. We aimed to establish the cause of aseptic peritonitis. We analysed 186 reports of aseptic peritonitis between September, 2001, and January, 2003. Extensive physical, chemical, and microbiological investigations of recalled dialysate were done. We calculated dose-response curves for peptidoglycan-induced interleukin 6 elaboration in peripheral blood mononuclear cells (PBMCs) from healthy donors and for sterile peritonitis in rats. Although its chemical constituents and concentrations of endotoxin were within pharmacopoeia specifications, the dialysis solution elicited an interlukin 6 response in vivo and in vitro. We identified peptidoglycan from thermophilic acidophilic bacteria (Alicyclobacillus acidocaldarius) as the contaminating proinflammatory substance. In the PBMC assay, strong dose-response relations were noted between peptidoglycan concentrations and interleukin 6. In rats injected with peptidoglycan, dose-dependent increases of intraperitoneal neutrophils and pyrogenic cytokines were recorded. We measured a positive relation between peptidoglycan concentrations in recalled dialysate and reports of aseptic peritonitis. After implementation of corrective actions, the rate of peritonitis returned to baseline. Excess cases of aseptic peritonitis in peritoneal dialysis patients were due to peptidoglycan contamination of dialysate by Alicyclobacillus. This outbreak serves as an example of how contemporary parenteral products with microbial contaminants can be considered safe under current pharmacopoeia tests, but provoke adverse clinical effects.

  14. New exact solutions of the standard pairing model for well-deformed nuclei

    SciTech Connect

    Pan Feng; Xie Mingxia; Guan Xin; Dai Lianrong; Draayer, J. P.

    2009-10-15

    A new step-by-step diagonalization procedure for evaluating exact solutions of the nuclear deformed mean-field plus pairing interaction model is proposed via a simple Bethe ansatz in each step from which the eigenvalues and corresponding eigenstates can be obtained progressively. This new approach draws upon an observation that the original one- plus two-body problem in a k-particle Hilbert subspace can be mapped onto a one-body grand hard-core boson picture that can be solved step by step with a simple Bethe ansatz known from earlier work. Based on this new procedure, it is further shown that the extended pairing model for deformed nuclei [Feng Pan, V. G. Gueorguiev, and J. P. Draayer, Phys. Rev. Lett. 92, 112503 (2004)] is similar to the standard pairing model with the first step approximation, in which only the lowest energy eigenstate of the standard pure pairing interaction part is taken into consideration. Our analysis shows that the standard pairing model with the first step approximation displays similar pair structures of the first few exact low-lying states of the model, which, therefore, provides a link between the two models.

  15. Trace element analysis of extraterrestrial metal samples by inductively coupled plasma mass spectrometry: the standard solutions and digesting acids.

    PubMed

    Wang, Guiqin; Wu, Yangsiqian; Lin, Yangting

    2016-02-28

    Nearly 99% of the total content of extraterrestrial metals is composed of Fe and Ni, but with greatly variable trace element contents. The accuracy obtained in the inductively coupled plasma mass spectrometry (ICP-MS) analysis of solutions of these samples can be significantly influenced by matrix contents, polyatomic ion interference, and the concentrations of external standard solutions. An ICP-MS instrument (X Series 2) was used to determine 30 standard solutions with different concentrations of trace elements, and different matrix contents. Based on these measurements, the matrix effects were determined. Three iron meteorites were dissolved separately in aqua regia and HNO3. Deviations due to variation of matrix contents in the external standard solutions were evaluated and the analysis results of the two digestion methods for iron meteorites were assessed. Our results show obvious deviations due to unmatched matrix contents in the external standard solutions. Furthermore, discrepancy in the measurement of some elements was found between the sample solutions prepared with aqua regia and HNO3, due to loss of chloride during sample preparation and/or incomplete digestion of highly siderophile elements in iron meteorites. An accurate ICP-MS analysis method for extraterrestrial metal samples has been established using external standard solutions with matched matrix contents and digesting the samples with HNO3 and aqua regia. Using the data from this work, the Mundrabilla iron meteorite previously classified as IAB-ung is reclassified as IAB-MG. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Standard enthalpy of formation of L-glutamine and the products of its dissociation in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Kochergina, L. A.; Lytkin, A. I.; Krutova, O. N.; Damrina, K. V.

    2014-03-01

    Heat effects of the dissolution of crystalline L-glutamine in water and lithium hydroxide solutions were determined by direct calorimetry at 298.15 K. Standard enthalpies of formation of L-glutamine and the products of its dissociation in aqueous solution were calculated.

  17. Standard enthalpies of formation of γ-aminobutyric acid and the products of its dissociation in aqueous solution

    NASA Astrophysics Data System (ADS)

    Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Skvortsov, I. A.; Korchagina, A. S.

    2016-09-01

    Heat effects of the dissolution of crystalline γ-aminobutyric acid in water and potassium hydroxide solutions are determined by direct colorimetry at 298.15 K. Standard enthalpies of formation of γ-aminobutyric acid and the products of its dissociation in aqueous solution are calculated.

  18. Global Time Dependent Solutions of Stochastically Driven Standard Accretion Disks: Development of Hydrodynamical Code

    NASA Astrophysics Data System (ADS)

    Wani, Naveel; Maqbool, Bari; Iqbal, Naseer; Misra, Ranjeev

    2016-07-01

    X-ray binaries and AGNs are powered by accretion discs around compact objects, where the x-rays are emitted from the inner regions and uv emission arise from the relatively cooler outer parts. There has been an increasing evidence that the variability of the x-rays in different timescales is caused by stochastic fluctuations in the accretion disc at different radii. These fluctuations although arise in the outer parts of the disc but propagate inwards to give rise to x-ray variability and hence provides a natural connection between the x-ray and uv variability. There are analytical expressions to qualitatively understand the effect of these stochastic variabilities, but quantitative predictions are only possible by a detailed hydrodynamical study of the global time dependent solution of standard accretion disc. We have developed numerical efficient code (to incorporate all these effects), which considers gas pressure dominated solutions and stochastic fluctuations with the inclusion of boundary effect of the last stable orbit.

  19. Preoperative whole pelvic external irradiation in Stage I endometrial cancer. [/sup 60/Co; /sup 226/Ra

    SciTech Connect

    Ritcher, N.; Lucas, W.E.; Yon, J.L.; Sanford, F.G.

    1981-07-01

    Between 1966 and 1978, 201 patients with adenocarcinoma of the endometrium were treated at two hospitals in San Diego. Of these patients, 161 had disease limited to the corpus at the time of diagnosis. The majority of these patients received external whole-pelvic irradiation, followed as soon as possible by simple extrafascial hysterectomy and bilateral salpingo-oophorectomy. When this treatment method was used, actuarial survivals of 95% for Stage I disease were achieved. Also reported is the low incidence of wound complications in the group of patients operated soon after cessation of irradiation. The patients treated in this fashion had good survival rates, little morbidity from the adjunctive irradiation, and fewer wound complications than previously anticipated.

  20. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; McAlister, Daniel R.

    2016-03-24

    A new method that rapidly preconcentrates and measures 226Ra from hydraulic fracturing wastewater samples was developed in the Savannah River Environmental Laboratory. The method improves the quality of 226Ra measurements using gamma spectrometry by providing up to 100x preconcentration of 226Ra from this difficult sample matrix, which contains very high levels of calcium, barium, strontium, magnesium and sodium. The high chemical yield, typically 80-90%, facilitates a low detection limit, important for lower level samples, and indicates method ruggedness. Ba-133 tracer is used to determine chemical yield and correct for geometry-related counting issues. The 226Ra sample preparation takes < 2 hours.

  1. A Deep Learning Solution for Automatic Fetal Neurosonographic Diagnostic Plane Verification Using Clinical Standard Constraints.

    PubMed

    Yaqub, Mohammad; Kelly, Brenda; Papageorghiou, Aris T; Noble, J Alison

    2017-09-25

    During routine ultrasound assessment of the fetal brain for biometry estimation and detection of fetal abnormalities, accurate imaging planes must be found by sonologists following a well-defined imaging protocol or clinical standard, which can be difficult for non-experts to do well. This assessment helps provide accurate biometry estimation and the detection of possible brain abnormalities. We describe a machine-learning method to assess automatically that transventricular ultrasound images of the fetal brain have been correctly acquired and meet the required clinical standard. We propose a deep learning solution, which breaks the problem down into three stages: (i) accurate localization of the fetal brain, (ii) detection of regions that contain structures of interest and (iii) learning the acoustic patterns in the regions that enable plane verification. We evaluate the developed methodology on a large real-world clinical data set of 2-D mid-gestation fetal images. We show that the automatic verification method approaches human expert assessment. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  2. Automatable on-line generation of calibration curves and standard additions in solution-cathode glow discharge optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Schwartz, Andrew J.; Ray, Steven J.; Hieftje, Gary M.

    2015-03-01

    Two methods are described that enable on-line generation of calibration standards and standard additions in solution-cathode glow discharge optical emission spectrometry (SCGD-OES). The first method employs a gradient high-performance liquid chromatography pump to perform on-line mixing and delivery of a stock standard, sample solution, and diluent to achieve a desired solution composition. The second method makes use of a simpler system of three peristaltic pumps to perform the same function of on-line solution mixing. Both methods can be computer-controlled and automated, and thereby enable both simple and standard-addition calibrations to be rapidly performed on-line. Performance of the on-line approaches is shown to be comparable to that of traditional methods of sample preparation, in terms of calibration curves, signal stability, accuracy, and limits of detection. Potential drawbacks to the on-line procedures include signal lag between changes in solution composition and pump-induced multiplicative noise. Though the new on-line methods were applied here to SCGD-OES to improve sample throughput, they are not limited in application to only SCGD-OES-any instrument that samples from flowing solution streams (flame atomic absorption spectrometry, ICP-OES, ICP-mass spectrometry, etc.) could benefit from them.

  3. Accurate determination of arsenic in arsenobetaine standard solutions of BCR-626 and NMIJ CRM 7901-a by neutron activation analysis coupled with internal standard method.

    PubMed

    Miura, Tsutomu; Chiba, Koichi; Kuroiwa, Takayoshi; Narukawa, Tomohiro; Hioki, Akiharu; Matsue, Hideaki

    2010-09-15

    Neutron activation analysis (NAA) coupled with an internal standard method was applied for the determination of As in the certified reference material (CRM) of arsenobetaine (AB) standard solutions to verify their certified values. Gold was used as an internal standard to compensate for the difference of the neutron exposure in an irradiation capsule and to improve the sample-to-sample repeatability. Application of the internal standard method significantly improved linearity of the calibration curve up to 1 microg of As, too. The analytical reliability of the proposed method was evaluated by k(0)-standardization NAA. The analytical results of As in AB standard solutions of BCR-626 and NMIJ CRM 7901-a were (499+/-55)mgkg(-1) (k=2) and (10.16+/-0.15)mgkg(-1) (k=2), respectively. These values were found to be 15-20% higher than the certified values. The between-bottle variation of BCR-626 was much larger than the expanded uncertainty of the certified value, although that of NMIJ CRM 7901-a was almost negligible.

  4. Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

    PubMed

    Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

    2006-01-01

    This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

  5. Kava hepatotoxicity solution: A six-point plan for new kava standardization.

    PubMed

    Teschke, Rolf; Sarris, Jerome; Lebot, Vincent

    2011-01-15

    Kava-induced liver injury has been demonstrated in a few patients worldwide and appears to be caused by inappropriate quality of the kava raw material. When cases of liver disease in connection with the use of kava emerged, this was an unexpected and challenging event considering the long tradition of safe kava use. In order to prevent kava hepatotoxicity in future, a set of quality specifications as standard is essential for the preparation not only of kava drugs and kava dietary supplements in the Western world but also for traditional kava drinks in the South Pacific Islands. For all these purposes a uniform approach is required, using water based extracts from the peeled rhizomes and roots of a noble cultivar such as Borogu with at least 5 years of age at the time of harvest. Cultivated in Vanuatu for centuries, noble varieties (as defined in the Vanuatu Kava Act of December 2002) are well tolerated traditional cultivars with a good safety record. At present, Vanuatu kava legislation is inadequately enforced to meet quality issues for kava, and further efforts are required in Vanuatu, in addition to similar legislation in other kava producing South Pacific Islands. Future regulatory and commercial strategies should focus not only on the standardization of kava drugs, kava dietary supplements, and traditional kava extracts, but also on thorough surveillance during the manufacturing process to improve kava quality for safe human use. The efficacy of kava extracts to treat patients with anxiety disorders is well supported, but further clinical trials with aqueous kava extracts are necessary. We thereby propose a six-point kava solution plan: (1) use of a noble kava cultivar such as Borogu, at least 5 years old at time of harvest, (2) use of peeled and dried rhizomes and roots, (3) aqueous extraction, (4) dosage recommendation of ≤250mg kavalactones per day (for medicinal use), (5) systematic rigorous future research, and (6) a Pan Pacific quality control system

  6. New solutions for standardization, monitoring and quality management of fluorescence-based imaging systems (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Royon, Arnaud; Papon, Gautier

    2016-03-01

    Fluorescence microscopes have become ubiquitous in life sciences laboratories, including those focused on pharmaceuticals, diagnosis, and forensics. For the past few years, the need for both performance guarantees and quantifiable results has driven development in this area. However, the lack of appropriate standards and reference materials makes it difficult or impossible to compare the results of two fluorescence microscopes, or to measure performance fluctuations of one microscope over time. Therefore, the operation of fluorescence microscopes is not monitored as often as their use warrants - an issue that is recognized by both systems manufacturers and national metrology institutes. We have developed a new process that enables the etching of long-term stable fluorescent patterns with sub-micrometer sizes in three dimensions inside glass. In this paper, we present, based on this new process, a fluorescent multi-dimensional ruler and a dedicated software that are suitable for monitoring and quality management of fluorescence-based imaging systems (wide-field, confocal, multiphoton, high content machines). In addition to fluorescence, the same patterns exhibit bright- and dark-field contrast, DIC, and phase contrast, which make them also relevant to monitor these types of microscopes. Non-exhaustively, this new solution enables the measurement of: The stage repositioning accuracy; The illumination and detection homogeneities; The field flatness; The detectors' characteristics; The lateral and axial spatial resolutions; The spectral response (spectrum, intensity and lifetime) of the system. Thanks to the stability of the patterns, microscope performance assessment can be carried out as well in a daily basis as in the long term.

  7. Standard thermodynamic functions of complexation between copper(II) and glycine and L-histidine in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Gorboletova, G. G.; Metlin, A. A.

    2016-09-01

    The Cu2+-glycine-L-histidine system is studied calorimetrically at 298.15 K and an ionic strength of 0.2, 0.5, and 1.0 in aqueous solutions containing potassium nitrate. The standard thermodynamic parameters (Δr H°, Δr G°, Δr S°) of complexation processes are determined.

  8. A model for large non-standard interactions of neutrinos leading to the LMA-Dark solution

    NASA Astrophysics Data System (ADS)

    Farzan, Yasaman

    2015-09-01

    It is well-known that in addition to the standard LMA solution to solar anomaly, there is another solution called LMA-Dark which requires Non-Standard Interactions (NSI) with effective couplings as large as the Fermi coupling. Although this solution satisfies all the bounds from various neutrino oscillation observations and even provides a better fit to low energy solar neutrino spectrum, it is not as popular as the LMA solution mainly because no model compatible with the existing bounds has been so far constructed to give rise to this solution. We introduce a model that provides a foundation for such large NSI with strength and flavor structure required for the LMA-Dark solution. This model is based on a new U(1) ‧ gauge interaction with a gauge boson of mass ∼ 10 MeV under which quarks as well as the second and third generations of leptons are charged. We show that observable effects can appear in the spectrum of supernova and high energy cosmic neutrinos. Our model predicts a new contribution to the muon magnetic dipole moment and new rare meson decay modes.

  9. Extraction of natural radionuclides from aqueous solutions by novel maltolate-based task-specific ionic liquids.

    PubMed

    Platzer, Sonja; Sap, Orhan; Leyma, Raphlin; Wallner, Gabriele; Jirsa, Franz; Kandioller, Wolfgang; Krachler, Regina; Keppler, Bernhard K

    Two novel maltol-based ionic liquids, namely [A336][Mal] and [C101][Mal], were synthesized as potential extracting agents for radionuclides from water. These two room temperature task-specific ionic liquids could be easily prepared by anion metathesis starting from commercially available materials. The isolated compounds were characterized by standard analytical methods. Their application as extraction agent for Unat., (234)Th, (210)Pb, (210)Bi, (210)Po and (226)Ra was elucidated by liquid-liquid extraction and scintillation counting. Uranium was totally extracted by both ionic liquids over a broad pH range (2-8), while the other radionuclides were removed with differing efficacies depending on the respective pH value.

  10. 77 FR 57055 - Regulatory New Drug Review: Solutions for Study Data Exchange Standards; Notice of Meeting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-17

    ... for Study Data Exchange Standards.'' The document was published with an incorrect email address. This...., Bldg. 51, Rm. 1160, Silver Spring, MD 20993-0002, 301-796-5333, FAX: 301-847-8443, email: CDERData... column, in the FOR FURTHER INFORMATION CONTACT section, the email address `` CDERDataStandards@hhs.fda...

  11. Structural Equation Models of Latent Interactions: An Appropriate Standardized Solution and Its Scale-Free Properties

    ERIC Educational Resources Information Center

    Wen, Zhonglin; Marsh, Herbert W.; Hau, Kit-Tai

    2010-01-01

    Standardized parameter estimates are routinely used to summarize the results of multiple regression models of manifest variables and structural equation models of latent variables, because they facilitate interpretation. Although the typical standardization of interaction terms is not appropriate for multiple regression models, straightforward…

  12. Classical solutions for the Lorentz-violating and CPT-even term of the standard model extension

    NASA Astrophysics Data System (ADS)

    Casana, Rodolfo; Ferreira, Manoel M., Jr.; Santos, Carlos E. H.

    2008-11-01

    In this work, we calculate the classical solutions for the electrodynamics stemming from the Lorentz-violating (LV) and CPT-even term of the standard model extension. Static and stationary solutions for pointlike and extended charges are obtained from the wave equations by means of the Green method. A dipolar expansion is written for the field strengths. It is explicitly shown that charge and current generate LV first order effects for the magnetic and electric fields, respectively. Using the magnetic field generated by a macroscopic 1C charged sphere, we establish a stringent bound for the LV parameter: κ≤10-16.

  13. Standards and solutions for architecture based, ontology driven and individualized pervasive health.

    PubMed

    Blobel, Bernd

    2012-01-01

    Based on the long-term work of scientific institutions and SDOs dedicated to system architectures, an interoperability framework is presented to help navigation through existing, emerging and even future standards for comprehensive interoperability of intelligent health and social care services. HL7 artifacts as well as work products of competing organizations are classified and semi-formally interrelated. The methodology is proven in many international standard development and health information systems implementation projects.

  14. Self-initiated and concentration-dependent degradation of tetracaine in neat standard solutions: A trouble-shooting story.

    PubMed

    Tan, Aimin; Wu, Yanxin; Gu, Guifen; Fanaras, John C

    2016-10-15

    This paper presents the trouble-shooting for a very unusual stability case. Tetracaine was found unstable in neat solutions only at high concentrations, but not at low concentrations. Moreover, its stable-isotope labeled internal standard did not show similar behavior. A series of trouble-shooting experiments were conducted to uncover the root cause. Some generally applicable precautions/insights can be drawn from this investigation to avoid potential stability issues during bioanalytical method development and validation.

  15. Calculation of the standard heat capacity at constant pressure for cobalt ferrite-zinc ferrite solid solutions

    SciTech Connect

    Chachanidze, G.D.; Pavlenishvili, T.A.; Machaladze, T.E.; Khutsishvili, D.I.

    1994-08-01

    Magnetic, electrical, and other properties of Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} solid solutions are widely studied because of their high coercive force and Curie temperature ({Tc}), which makes these compounds applicable in modern electronic devices. However, the information published on their thermodynamic properties is limited. This paper focuses on calculation of the standard heat capacity C{sub p}{sup 0} (298 K) for cobalt zinc ferrites using correlation analysis of the relationship between C{sub p}{sup 0} (298 K) and the saturation magnetic moment {mu}{sub o}. The authors studied the solid solutions Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.2, 0.4, 0.5, 0.6, and 0.8), whose magnetic and thermal parameters, crucial in our calculations, are known to be strongly dependent on the preparation conditions. An equation was derived for calculation of the standard heat capacity at constant pressure from the saturation magnetic moment of Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} solid solutions. The equation allows a satisfactory estimation of the standard heat capacity at 298 Kelvin for any cobalt ferrite-zinc ferrite solid, providing the saturation magnetic moment is available.

  16. Efficacy of handrubbing with alcohol based solution versus standard handwashing with antiseptic soap: randomised clinical trial

    PubMed Central

    Girou, Emmanuelle; Loyeau, Sabrina; Legrand, Patrick; Oppein, Françoise; Brun-Buisson, Christian

    2002-01-01

    Objective To compare the efficacy of handrubbing with an alcohol based solution versus conventional handwashing with antiseptic soap in reducing hand contamination during routine patient care. Design Randomised controlled trial during daily nursing sessions of 2 to 3 hours. Setting Three intensive care units in a French university hospital. Participants 23 healthcare workers. Interventions Handrubbing with alcohol based solution (n=12) or handwashing with antiseptic soap (n=11) when hand hygiene was indicated before and after patient care. Imprints taken of fingertips and palm of dominant hand before and after hand hygiene procedure. Bacterial counts quantified blindly. Main outcome measures Bacterial reduction of hand contamination. Results With handrubbing the median percentage reduction in bacterial contamination was significantly higher than with handwashing (83% v 58%, P=0.012), with a median difference in the percentage reduction of 26% (95% confidence interval 8% to 44%). The median duration of hand hygiene was 30 seconds in each group. Conclusions During routine patient care handrubbing with an alcohol based solution is significantly more efficient in reducing hand contamination than handwashing with antiseptic soap. What is already known on this topicTo improve compliance with hand hygiene during patient care, handrubbing with an alcohol based solution has been proposed as a substitute for handwashing because of its rapid action and accessibilityExperimental studies show that handrubbing is at least as effective as medicated soap in reducing artificial contamination of handsMany healthcare workers still have reservations regarding its efficacy and are reluctant to use this techniqueWhat this study addsWhen used in routine practice, handrubbing with an alcohol based solution after contact with patients achieved a greater reduction in bacterial contamination of hands than conventional handwashing with medicated soap PMID:12183307

  17. Convergence and Periodic Solutions for the Input Impedance of a Standard Ladder Network

    ERIC Educational Resources Information Center

    Ucak, C.; Acar, C.

    2007-01-01

    The input impedance of an infinite ladder network is computed by using the recursive relation and by assuming that the input impedance does not change when a new block is added to the network. However, this assumption is not true in general and standard textbooks do not always treat these networks correctly. This paper develops a general solution…

  18. Convergence and Periodic Solutions for the Input Impedance of a Standard Ladder Network

    ERIC Educational Resources Information Center

    Ucak, C.; Acar, C.

    2007-01-01

    The input impedance of an infinite ladder network is computed by using the recursive relation and by assuming that the input impedance does not change when a new block is added to the network. However, this assumption is not true in general and standard textbooks do not always treat these networks correctly. This paper develops a general solution…

  19. The Determination of the pH of Standard Buffer Solution: A Laboratory Experiment.

    ERIC Educational Resources Information Center

    Harris, K. R.

    1985-01-01

    Describes an experiment which shows: (1) how measurements of the reaction electromotive force for the cell (Pt/glass/NaCl(aq,m),buffer/AgCl/Ag/Pt) can be utilized in determining the absolute pH of the buffer; and (2) the demonstration of the use of the Debye-Huckel model of an electrolyte solution in solving an important electrochemical problem.…

  20. Gold standards and expert panels: a pulmonary nodule case study with challenges and solutions

    NASA Astrophysics Data System (ADS)

    Miller, Dave P.; O'Shaughnessy, Kathryn F.; Wood, Susan A.; Castellino, Ronald A.

    2004-05-01

    Comparative evaluations of reader performance using different modalities, e.g. CT with computer-aided detection (CAD) vs. CT without CAD, generally require a "truth" definition based on a gold standard. There are many situations in which a true invariant gold standard is impractical or impossible to obtain. For instance, small pulmonary nodules are generally not assessed by biopsy or resection. In such cases, it is common to use a unanimous consensus or majority agreement from an expert panel as a reference standard for actionability in lieu of the unknown gold standard for disease. Nonetheless, there are three major concerns about expert panel reference standards: (1) actionability is not synonymous with disease (2) it may be possible to obtain different conclusions about which modality is better using different rules (e.g. majority vs. unanimous consensus), and (3) the variability associated with the panelists is not formally captured in the p-values or confidence intervals that are generally produced for estimating the extent to which one modality is superior to the other. A multi-reader-multi-case (MRMC) receiver operating characteristic (ROC) study was performed using 90 cases, 15 readers, and a reference truth based on 3 experienced panelists. The primary analyses were conducted using a reference truth of unanimous consensus regarding actionability (3 out of 3 panelists). To assess the three concerns noted above: (1) additional data from the original radiology reports were compared to the panel (2) the complete analysis was repeated using different definitions of truth, and (3) bootstrap analyses were conducted in which new truth panels were constructed by picking 1, 2, or 3 panelists at random. The definition of the reference truth affected the results for each modality (CT with CAD and CT without CAD) considered by itself, but the effects were similar, so the primary analysis comparing the modalities was robust to the choice of the reference truth.

  1. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology.

    PubMed

    Temple, Blake; Smoller, Joel

    2009-08-25

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy.

  2. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology

    PubMed Central

    Temple, Blake; Smoller, Joel

    2009-01-01

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy. PMID:19706502

  3. Motion control solution for new PLC-based standard development platform for VLT instrument control systems

    NASA Astrophysics Data System (ADS)

    Popovic, D.; Brast, R.; Di Lieto, N.; Kiekebusch, M.; Knudstrup, J.; Lucuix, C.

    2014-07-01

    More than a decade ago, due to obsolescence issues, ESO initiated the design and implementation of a custom-made CANbus based motion controller (CAN-RMC) to provide, together with a tailor-made software library (motor library), the motion control capabilities for the VME platform needed for the second generation VLT/VLTI instruments. The CAN-RMC controller has been successfully used in a number of VLT instruments but it has high production costs compared to the commercial off-the-shelf (COTS) industrial solutions available on the market today. In the scope of the selection of a new PLC-based platform for the VLT instrument control systems, ESO has evaluated motion control solutions from the company Beckhoff. This paper presents the investigation, implementation and testing of the PLC/TwinCAT/EtherCAT motion controllers for DC and stepper motors and their adaptation and integration into the VLT instrumentation framework. It reports functional and performance test results for the most typical use cases of astronomical instruments like initialization sequences, tracking, switch position detections, backslash compensation, brake handling, etc. In addition, it gives an overview of the main features of TwinCAT NC/PTP, PLCopen MC, EtherCAT motion control terminals and the engineering tools like TwinCAT Scope that are integrated into the development environment and simplify software development, testing and commissioning of motorized instrument functions.

  4. Radon concentration levels in ground water from Toluca, Mexico.

    PubMed

    Olguin, M T; Segovia, N; Tamez, E; Alcántara, M; Bulbulian, S

    1993-03-25

    Concentration levels of 222Rn have been analysed in water samples from deep wells of the aquifers around the City of Toluca, Mexico. The 222Rn source is the decay of 226Ra within the solid matrix of the aquifer. With a half life of 1600 years the 226Ra continuously releases 222Rn to the pores, from which it diffuses into the main body of water. This paper describes the methods used for sampling and measuring solubilized and 226Ra-supported 222Rn in the water samples, in order to evaluate possible health hazards due to the presence of radon in the drinking water supplies. The relationship of 222Rn with the hydrogeologic characteristics of the zone is also described. The analytical method involves laboratory extraction of 222Rn into toluene. Alpha disintegrations of 222Rn and contributions from short-lived daughters are counted by the liquid scintillation technique. The system was calibrated using a 226Ra standard solution. Results up to 11.3 Bq/l of 222Rn were obtained in the water samples.

  5. Asymptotic solution of the optimal control problem for standard systems with delay

    SciTech Connect

    Zheltikov, V.P.; Efendiev, V.V.

    1995-05-01

    The authors consider the construction of an asymptotic solution of the terminal optimal control problem using the averaging method. The optimal process is described by the equation z = eZ (t, z, z(t-l, e, u), u), z/t=[-1,0] = {var_phi}(t), where the delay is constant and of unit magnitude, z {element_of} G is an n-dimensional vector, G {contained_in} R{sup n}, e > 0 is a small parameter, t {element_of} T {triple_bond} [0, e{sup -1}], Z {var_phi} are n-dimensional vector functions, Z is strictly convex in u for any (t, z) {element_of} T X G, u {element_of} U is the r-dimensional control vector, U is a compact set.

  6. Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

    PubMed

    el-Mougi, M; Hendawi, A; Koura, H; Hegazi, E; Fontaine, O; Pierce, N F

    1996-01-01

    Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates

  7. Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption.

    PubMed Central

    el-Mougi, M.; Hendawi, A.; Koura, H.; Hegazi, E.; Fontaine, O.; Pierce, N. F.

    1996-01-01

    Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates

  8. Synthesis and characterization of LTA nanozeolite using barley husk silica: Mercury removal from standard and real solutions

    SciTech Connect

    Azizi, Seyed Naser; Dehnavi, Ahmad Roozbehani; Joorabdoozha, Amir

    2013-05-15

    Highlights: ► Silica extraction from barley husk with high purity for the synthesis of A nanozeolite. ► Free template A nanozeolite synthesized via new source of silica at low temperature. ► Optimization of SiO{sub 2}/Al{sub 2}O{sub 3}, Na{sub 2}O/SiO{sub 2} ratios, temperature and time of the synthesis. ► Utilizing of synthesized A nanozeolite for mercury removal from aqueous solutions. ► Mercury removal at optimized pH, contact time and adsorbent dose from real solution. - Abstract: In this study, synthesized Lined Type A (LTA) nanozeolite from barley husk silica (BHS) was used for mercury removal from standard and real aqueous solutions. The BHS in amorphous phase with 80% purity was extracted from barley husk ash (BHA), and used effectively as a new source of silica for the synthesis of NaA nanozeolite. The NaA nanocrystal in pure phase has been synthesized at low temperature, without adding any organic additives. The effects of heating time, reaction temperature, SiO{sub 2}/Al{sub 2}O{sub 3}, and Na{sub 2}O/SiO{sub 2} mole ratios on the crystallization of NaA nanozeolite were studied. The adsorption capacity of mercury (II) was studied as a function of pH, contact time, and amount of adsorbent. The crystallization of NaA nanozeolite from BHS was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Brunauer–Emmett–Teller (BET), and FTIR techniques. Moreover, concentration of Hg{sup 2+} ions in the aqueous solutions was analyzed by hydride generation atomic absorption spectroscopy method (HG-AAS). The standard and real samples analysis showed that NaA nanozeolite is capable of Hg{sup 2+} ions removal from the aqueous solutions. Efficiency of mercury (II) adsorption from real solutions onto the nano-sized NaA zeolite was 98%.

  9. [Problems and ways of solutions to harmonize standards for air pollution].

    PubMed

    Avaliani, S L; Novikov, S M; Shashina, T A; Skvortsova, N S; Kislitsin, V A; Mishina, A L

    2012-01-01

    In the article the basic problems of harmonization of domestic regulatory framework of air pollution with the WHO recommendations and normative values adopted in the EU, U.S. and other countries are considered. The important role of health risk analysis methodology in the process of harmonization of regulation and control of air quality has been pointed out. The necessity of radical changes in the structure and content of the basic normative document GN 2.1.6.1338-03 "maximum permissible concentration (MPC) of pollutants in the air of populated areas" has been shown. The algorithm of the procedure that justifies the new list of normative values in the air harmonized with international recommendations and standards of developed countries has been proposed.

  10. Quantitative 1H NMR with external standards: use in preparation of calibration solutions for algal toxins and other natural products.

    PubMed

    Burton, Ian W; Quilliam, Michael A; Walter, John A

    2005-05-15

    We examine the use of external standards for quantitative measurement by 1H NMR of solution concentrations of natural products and other low molecular weight, hydrogen-containing compounds and show that precision and accuracy ca. 1% is obtainable with a commercial 11.7 T spectrometer when standards and analytes are contained in separate but identical sealed precision glass NMR tubes. Numerous factors contributing to the intensity of the NMR signals are evaluated. Precise measurements of 360 degrees pulse lengths for each sample provide direct corrections for variations in probe Q-factor that enable samples in different solvents to be compared, provided single-coil excitation and detection is used throughout. Samples need not be prepared in deuterated solvents if the 1H spectra of the solvents are simple enough for peak suppression by presaturation. The approach is particularly suitable for hazardous materials kept in sealed tubes and for the preparation of certified calibration solution reference materials for use with LC-MS and other techniques where deuterated solvents should be avoided.

  11. The RICORDO approach to semantic interoperability for biomedical data and models: strategy, standards and solutions

    PubMed Central

    2011-01-01

    Background The practice and research of medicine generates considerable quantities of data and model resources (DMRs). Although in principle biomedical resources are re-usable, in practice few can currently be shared. In particular, the clinical communities in physiology and pharmacology research, as well as medical education, (i.e. PPME communities) are facing considerable operational and technical obstacles in sharing data and models. Findings We outline the efforts of the PPME communities to achieve automated semantic interoperability for clinical resource documentation in collaboration with the RICORDO project. Current community practices in resource documentation and knowledge management are overviewed. Furthermore, requirements and improvements sought by the PPME communities to current documentation practices are discussed. The RICORDO plan and effort in creating a representational framework and associated open software toolkit for the automated management of PPME metadata resources is also described. Conclusions RICORDO is providing the PPME community with tools to effect, share and reason over clinical resource annotations. This work is contributing to the semantic interoperability of DMRs through ontology-based annotation by (i) supporting more effective navigation and re-use of clinical DMRs, as well as (ii) sustaining interoperability operations based on the criterion of biological similarity. Operations facilitated by RICORDO will range from automated dataset matching to model merging and managing complex simulation workflows. In effect, RICORDO is contributing to community standards for resource sharing and interoperability. PMID:21878109

  12. Evaluation of the Ross fast solution of Richards’ equation in unfavourable conditions for standard finite element methods

    NASA Astrophysics Data System (ADS)

    Crevoisier, David; Chanzy, André; Voltz, Marc

    2009-06-01

    Ross [Ross PJ. Modeling soil water and solute transport - fast, simplified numerical solutions. Agron J 2003;95:1352-61] developed a fast, simplified method for solving Richards' equation. This non-iterative 1D approach, using Brooks and Corey [Brooks RH, Corey AT. Hydraulic properties of porous media. Hydrol. papers, Colorado St. Univ., Fort Collins; 1964] hydraulic functions, allows a significant reduction in computing time while maintaining the accuracy of the results. The first aim of this work is to confirm these results in a more extensive set of problems, including those that would lead to serious numerical difficulties for the standard numerical method. The second aim is to validate a generalisation of the Ross method to other mathematical representations of hydraulic functions. The Ross method is compared with the standard finite element model, Hydrus-1D [Simunek J, Sejna M, Van Genuchten MTh. The HYDRUS-1D and HYDRUS-2D codes for estimating unsaturated soil hydraulic and solutes transport parameters. Agron Abstr 357; 1999]. Computing time, accuracy of results and robustness of numerical schemes are monitored in 1D simulations involving different types of homogeneous soils, grids and hydrological conditions. The Ross method associated with modified Van Genuchten hydraulic functions [Vogel T, Cislerova M. On the reliability of unsaturated hydraulic conductivity calculated from the moisture retention curve. Transport Porous Media 1988;3:1-15] proves in every tested scenario to be more robust numerically, and the compromise of computing time/accuracy is seen to be particularly improved on coarse grids. Ross method run from 1.25 to 14 times faster than Hydrus-1D.

  13. Do PCDD/PCDF standard solutions used in dioxin analysis pose a risk as potentially acutely toxic to lab personnel?

    PubMed

    Malisch, Rainer; Denison, Michael S; Fiedler, Heidelore; Fürst, Peter; Hoogenboom, Ron L A P; Schaechtele, Alexander; Schrenk, Dieter; van den Berg, Martin

    2017-10-01

    Laboratory safety requires protecting personnel from chemical exposures. Working with stock solutions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) in routine analysis of feed and food with bioanalytical or physicochemical methods raises some concerns. Since PCDD/PCDFs are considered as possibly acutely toxic, the potential risks were evaluated to determine whether supervision of their use is necessary. Based on LD50-data for oral or dermal intake, hazard classification of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a substance (category 1) and in commercially available TCDD standard solutions (category 4) is different. As worst case exposure scenario during routine laboratory work it was assumed that a dose of 100 ng TCDD gets onto the skin and is absorbed. This would result in the total body burden of a 70 kg person with 15 kg fat increasing from 10 (upper range of current background levels) to ∼17 pg of toxic equivalents (TEQs) of PCDD/PCDFs per g lipid, a level commonly observed over past decades. Chloracne, the main acute effect occurring weeks after exposure, is observed at much higher blood concentrations than estimated from accidental laboratory exposure. Immunotoxicity, developmental effects and other toxic effects may occur at lower blood levels, but require longer periods to develop. Since acute toxic symptoms don't occur within an "8 h acute time window", no supervision is necessary when working with standard solutions in routine analysis. Nevertheless, precautionary measures are needed regarding long-term adverse health effects and appropriate workplace conditions must exist to ensure that additional occupational exposure to PCDD/PCDFs by laboratory personnel is negligible. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A SOA broker solution for standard discovery and access services: the GI-cat framework

    NASA Astrophysics Data System (ADS)

    Boldrini, Enrico

    2010-05-01

    GI-cat ideal users are data providers or service providers within the geoscience community. The former have their data already available through an access service (e.g. an OGC Web Service) and would have it published through a standard catalog service, in a seamless way. The latter would develop a catalog broker and let users query and access different geospatial resources through one or more standard interfaces and Application Profiles (AP) (e.g. OGC CSW ISO AP, CSW ebRIM/EO AP, etc.). GI-cat actually implements a broker components (i.e. a middleware service) which carries out distribution and mediation functionalities among "well-adopted" catalog interfaces and data access protocols. GI-cat also publishes different discovery interfaces: the OGC CSW ISO and ebRIM Application Profiles (the latter coming with support for the EO and CIM extension packages) and two different OpenSearch interfaces developed in order to explore Web 2.0 possibilities. An extended interface is also available to exploit all available GI-cat features, such as interruptible incremental queries and queries feedback. Interoperability tests performed in the context of different projects have also pointed out the importance to enforce compatibility with existing and wide-spread tools of the open source community (e.g. GeoNetwork and Deegree catalogs), which was then achieved. Based on a service-oriented framework of modular components, GI-cat can effectively be customized and tailored to support different deployment scenarios. In addition to the distribution functionality an harvesting approach has been lately experimented, allowing the user to switch between a distributed and a local search giving thus more possibilities to support different deployment scenarios. A configurator tool is available in order to enable an effective high level configuration of the broker service. A specific geobrowser was also naturally developed, for demonstrating the advanced GI-cat functionalities. This client

  15. Design challenges and gaps in standards in developing an interoperable zero footprint DI thin client for use in image-enabled electronic health record solutions

    NASA Astrophysics Data System (ADS)

    Agrawal, Arun; Koff, David; Bak, Peter; Bender, Duane; Castelli, Jane

    2015-03-01

    The deployment of regional and national Electronic Health Record solutions has been a focus of many countries throughout the past decade. A major challenge for these deployments has been support for ubiquitous image viewing. More specifically, these deployments require an imaging solution that can work over the Internet, leverage any point of service device: desktop, tablet, phone; and access imaging data from any source seamlessly. Whereas standards exist to enable ubiquitous image viewing, few if any solutions exist that leverage these standards and meet the challenge. Rather, most of the currently available web based DI viewing solutions are either proprietary solutions or require special plugins. We developed a true zero foot print browser based DI viewing solution based on the Web Access DICOM Objects (WADO) and Cross-enterprise Document Sharing for Imaging (XDS-I.b) standards to a) demonstrate that a truly ubiquitous image viewer can be deployed; b) identify the gaps in the current standards and the design challenges for developing such a solution. The objective was to develop a viewer, which works on all modern browsers on both desktop and mobile devices. The implementation allows basic viewing functionalities of scroll, zoom, pan and window leveling (limited). The major gaps identified in the current DICOM WADO standards are a lack of ability to allow any kind of 3D reconstruction or MPR views. Other design challenges explored include considerations related to optimization of the solution for response time and low memory foot print.

  16. Organic solution-processible electroluminescent molecular glasses for non-doped standard red OLEDs with electrically stable chromaticity

    SciTech Connect

    Bi, Xiaoman; Zuo, Weiwei; Liu, Yingliang Zhang, Zhenru; Zeng, Cen; Xu, Shengang; Cao, Shaokui

    2015-10-15

    Highlights: • The D–A–D electroluminescent molecular glasses are synthesized. • Non-doped red electroluminescent film is fabricated by spin-coating. • Red OLED shows stable wavelength, luminous efficiency and chromaticity. • CIE1931 coordinate is in accord with standard red light in PAL system. - Abstract: Organic light-emitting molecular glasses (OEMGs) are synthesized through the introduction of nonplanar donor and branched aliphatic chain into electroluminescent emitters. The target OEMGs are characterized by {sup 1}H NMR, {sup 13}C NMR, IR, UV–vis and fluorescent spectra as well as elemental analysis, TG and DSC. The results indicated that the optical, electrochemical and electroluminescent properties of OEMGs are adjusted successfully by the replacement of electron-donating group. The non-doped OLED device with a standard red electroluminescent emission is achieved by spin-coating the THF solution of OEMG with a triphenylamine moiety. This non-doped red OLED device takes on an electrically stable electroluminescent performance, including the stable maximum electroluminescent wavelength of 640 nm, the stable luminous efficiency of 2.4 cd/A and the stable CIE1931 coordinate of (x, y) = (0.64, 0.35), which is basically in accord with the CIE1931 coordinate (x, y) = (0.64, 0.33) of standard red light in PAL system.

  17. Comparative antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solutions evaluated using a novel standardized assay.

    PubMed

    Thorn, R M S; Robinson, G M; Reynolds, D M

    2013-05-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces.

  18. Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay

    PubMed Central

    Thorn, R. M. S.; Robinson, G. M.

    2013-01-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces. PMID:23459480

  19. Standard Gibbs free energies of reactions of ozone with free radicals in aqueous solution: quantum-chemical calculations.

    PubMed

    Naumov, Sergej; von Sonntag, Clemens

    2011-11-01

    Free radicals are common intermediates in the chemistry of ozone in aqueous solution. Their reactions with ozone have been probed by calculating the standard Gibbs free energies of such reactions using density functional theory (Jaguar 7.6 program). O(2) reacts fast and irreversibly only with simple carbon-centered radicals. In contrast, ozone also reacts irreversibly with conjugated carbon-centered radicals such as bisallylic (hydroxycylohexadienyl) radicals, with conjugated carbon/oxygen-centered radicals such as phenoxyl radicals, and even with nitrogen- oxygen-, sulfur-, and halogen-centered radicals. In these reactions, further ozone-reactive radicals are generated. Chain reactions may destroy ozone without giving rise to products other than O(2). This may be of importance when ozonation is used in pollution control, and reactions of free radicals with ozone have to be taken into account in modeling such processes.

  20. Standards, calibration and quality assurance of 222Rn measurements in Sweden

    NASA Astrophysics Data System (ADS)

    Falk, R.; Hagberg, N.; Mjönes, L.; Möre, H.; Nyblom, L.; Swedjemark, G. A.

    1994-01-01

    Inhaled decay products of 222Rn are the dominant components of the natural radiation exposure to the general population. Limits have been introduced in Sweden, and recommendations were made in 1980 for decreasing indoor 222Rn concentration. The need for the coordinated calibration of measuring instruments as well as for quality assurance was obvious for both health and economic reasons. 222Rn measurements in Sweden are based on standards traceable to the National Institute of Standard and Technology (NIST) through the use of standard reference material 226Ra. Standards for both 222Rn and short-lived 222Rn progeny are described together with the reference instrument adopted for these studies. The calibration of field instruments was performed in a "radon room", a climate chamber in which it is possible to vary and monitor the concentration of 222Rn as well as other characteristics of the indoor air such as temperature, humidity, ventilation rate and aerosol concentration. The rules and regulations for field measurements imply a calibration of the instruments yearly, as well as accreditation and training for the companies that carry out the measurements. Examples are given of the official measurement protocols used for the different types of instruments.

  1. Measurement of {sup 222}Rn flux, {sup 222}Rn emanation and {sup 226}Ra concentration from injection well pipe scale

    SciTech Connect

    Rood, A.S.; Kendrick, D.T.

    1996-02-01

    The presence of Naturally Occurring Radioactive Material (NORM) has been recognized since the early 1930s in petroleum reservoirs and in oil and gas production and processing facilities. NORM was typically observed in barite scale that accumulated on the interior of oil production tubing and in storage tank and heater-treater separation sludge. Recent concern has been expressed over the health impacts from the uncontrolled release of NORM to the public. There are several potential exposure pathways to humans from oil-field NORM. Among these is inhalation of radon gas and its daughter products. For this exposure pathway to be of any significance, radon must first be released from the NORM matrix and diffuse in free air. The radon emanation fraction refers to the fraction of radon atoms produced by the decay of radium, that migrate from the bulk material as free gaseous atoms. The purpose of this investigation was to characterize the radon release rates from NORM-scale contaminated production tubing being stored above ground, characterize the radon emanation fraction of the bulk scale material when removed from the tubing, and characterize the radium concentrations of the scale. Accurate characterization of {sup 222}Rn emanation fractions from pipe scale may dictate the type of disposal options available for this waste. Characterization of radon release from stored pipes will assist in determining if controls are needed for workers or members of the public downwind from the source. Due to the sensitive nature of this data, the location of this facility is not disclosed.

  2. Ultrafast source-to-surface movement of melt at island arcs from 226Ra-230Th systematics.

    PubMed

    Turner, S; Evans, P; Hawkesworth, C

    2001-05-18

    Island arc lavas have radium-226 excesses that extend to higher values than those observed in mid-ocean ridge or ocean island basalts. The initial ratio of radium-226 to thorium-230 is largest in the most primitive lavas, which also have the highest barium/thorium ratios, and decreases with increasing magmatic differentiation. Therefore, the radium-226 excesses appear to have been introduced into the base of the mantle melting column by fluids released from the subducting plate. Preservation of this signal requires transport to the surface arguably in only a few hundreds of years and directly constrains the average melt velocity to the order of 1000 meters per year. Thus, melt segregation and channel formation can occur rapidly in the mantle.

  3. A garage sale bargain: A leaking 2.2 GBq {sup 226}Ra source, Phase 1 - the incident

    SciTech Connect

    Freeman, B.; Andrews, M.; Hogan, A.

    1996-06-01

    In March 1995, a private citizen living in Bristol, Tennessee, went to a local garage sale and purchased a box containing old medical equipment and paraphernalia for $10.00. The man put the box in the trunk of his car where it remained for several weeks. He then took the box into his home where he examined all of the items, including a small wooden box with a metal sleeve. After significant effort, he managed to remove the inner box which bore the word {open_quotes}radium.{close_quotes} Unsure of what this meant, he called his son-in-law who understood that radium was a radioactive material and called the Tennessee Division of Radiological Health (TDRH). The TDRH investigation quickly located and isolated the source and determined that the contamination was spread throughout the man`s home and yard. Exposure rate readings as high as 160 mR h{sup -1} were found along with removable contamination as high as 3,000,000 dpm/100 cm{sup 2}. Over the next several days, the TDRH organized a voluntary effort for the medical evaluation of the man and his wife, the removal of the source, and the decontamination of the home, yard, car, etc. The two following papers will describe these aspects of this incident. On 26 May 1995, the remediation was completed, ending this unusual, but not unique, radiation incident.

  4. Thermal modulation voltammetry with laser heating at an aqueous|nitrobenzene solution microinterface: determination of the standard entropy changes of transfer for tetraalkylammonium ions.

    PubMed

    Hinoue, Teruo; Ikeda, Eiji; Watariguchi, Shigeru; Kibune, Yasuyuki

    2007-01-01

    Thermal modulation voltammetry (TMV) with laser heating was successfully performed at an aqueous|nitrobenzene (NB) solution microinterface, by taking advantage of the fact that laser light with a wavelength of 325.0 nm is optically transparent to the aqueous solution but opaque to the NB solution. When the laser beam impinges upon the interface from the aqueous solution side, a temperature is raised around the interface through the thermal diffusion subsequent to the light-to-heat conversion following the optical absorption by the NB solution near the interface. Based on such a principle, we achieved a fluctuating temperature perturbation around the interface for TMV by periodically irradiating the interface with the laser beam. On the other hand, the fluctuating temperature perturbation has influence on currents for transfer of an ion across the interface to produce fluctuating currents synchronized with the perturbation through temperature coefficients of several variables concerning the transfer, such as the standard transfer potential and the diffusion coefficient of the ion. Consequently, TMV has the possibility of providing information about the standard entropy change of transfer corresponding to a temperature coefficient of the standard transfer potential and a temperature coefficient of the diffusion coefficient. In this work, the aqueous|NB solution interface of 30 microm in diameter was irradiated with the laser beam at 10 Hz, and the currents synchronized with the periodical irradiation were recorded as a function of the potential difference across the interface in order to construct a TM voltammogram. TM voltammograms were measured for transfer of tetramethylammonium, tetraethylammonium, tetrapropylammonium, and tetra-n-butylammonium ions from the aqueous solution to the NB solution, and the standard entropy change of transfer was determined for each ion, according to an analytical procedure based on a mathematical expression of the TM voltammogram

  5. Report of the CCQM-K97: measurement of arsenobetaine standard solution and arsenobetaine content in fish tissue (tunafish)

    NASA Astrophysics Data System (ADS)

    Ma, L. D.; Wang, J.; WEI, C.; Kuroiwa, T.; Narukawa, T.; Ito, N.; HIOKI, A.; CHIBA, K.; Yim, Y. H.; Lee, K. S.; Lim, Y. R.; Turk, G. C.; Davis, C. W.; Mester, Z.; Yang, L.; McCooeye, M.; Maxwell, P.; Cankur, O.; Tokman, N.; Coskun, F. G.

    2017-01-01

    The CCQM-K97 key comparison was organized by the inorganic analysis working group (IAWG) of CCQM as a follow-up to completed pilot study CCQM-P96 and P96.1 to test the abilities of the national metrology institutes to accurately quantitate the mass fraction of arsenobetaine (AsB) in standard solution and in fish tissue. A pilot study CCQM-P133 was parallelized with this key comparison. National Institute of Metrology (NIM), China and National Metrology Institute of Japan (NMIJ) acted as the coordinating laboratories. Six NMIs participated in CCQM-K97 and two institutes participated in CCQM-P133, and all of them submitted the results. Some NMIs submitted more than one results by different methods. The results were in excellent agreement with each other, and obviously better than those of previous P96 and P96.1. Therefore the calibrant which each NMI used was comparable. It shows that the capabilities of some of the participants have been improved after the previous pilot studies. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  6. An In Silico study of TiO2 nanoparticles interaction with twenty standard amino acids in aqueous solution

    NASA Astrophysics Data System (ADS)

    Liu, Shengtang; Meng, Xuan-Yu; Perez-Aguilar, Jose Manuel; Zhou, Ruhong

    2016-11-01

    Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts. By calculating the Potential Mean Force, we showed that Arg is prone to direct binding onto the NP surface, while Lys needs to overcome a ~2 kT free energy barrier. On the other hand, acidic residues tend to form “water bridges” between their sidechains and TiO2 surface, thus displaying an indirect binding. Moreover, the overall preferred positions and configurations of different residues are highly dependent on properties of the first and second solvation water. These molecular insights learned from this work might help with a better understanding of the interactions between biomolecules and nanomaterials.

  7. An In Silico study of TiO2 nanoparticles interaction with twenty standard amino acids in aqueous solution

    PubMed Central

    Liu, Shengtang; Meng, Xuan-Yu; Perez-Aguilar, Jose Manuel; Zhou, Ruhong

    2016-01-01

    Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts. By calculating the Potential Mean Force, we showed that Arg is prone to direct binding onto the NP surface, while Lys needs to overcome a ~2 kT free energy barrier. On the other hand, acidic residues tend to form “water bridges” between their sidechains and TiO2 surface, thus displaying an indirect binding. Moreover, the overall preferred positions and configurations of different residues are highly dependent on properties of the first and second solvation water. These molecular insights learned from this work might help with a better understanding of the interactions between biomolecules and nanomaterials. PMID:27883086

  8. [Validation Study on a Multi-Residue Method for Determination of Pesticide Residues in Vegetables and Fruits by using General Matrix Standard Solutions].

    PubMed

    Fukui, Naoki; Takatori, Satoshi; Yamaguchi, Satoko; Kitagawa, Yoko; Yoshimitsu, Masato; Osakada, Masakazu; Kajimura, Keiji; Obana, Hirotaka

    2015-01-01

    Quantitative methods using the matrix-matched standard solutions approach are widely used for multi-residue pesticide determination by GC-MS/MS to deal with the issue of matrix effects. However, preparing matrix-matched standard solutions in analyses of many kinds of samples is very time-consuming. In order to solve this problem, a method that employs general matrix standard solutions has been developed using polyethylene glycol (PEG), extract of vegetables-fruit juice (VFJm) and triphenyl phosphate (named the PEG-VFJm method). Here, a validation study for 168 pesticides was performed on three kinds of samples [potato, spinach and apple] at concentrations of 0.010 and 0.050 μg/g. In these three commodities, 144 to 158 pesticides satisfied the required criteria using the matrix-matched method and 129 to 149 pesticides satisfied the same criteria using the PEG-VFJm method. Our results suggest that application of general matrix standard solutions would enable rapid and effective analyses of pesticides.

  9. Innovative solutions: Standardized concentrations facilitate the use of continuous infusions for pediatric intensive care unit nurses at a community hospital.

    PubMed

    Roman, Noemi

    2005-01-01

    The pediatric intensive care unit at a community hospital successfully implemented the use of standardized concentrations. The process included deciding the standardized concentrations, use of titration charts, and integration of smart pump technology. Since the implementation of standardized concentrations, there has been no signal or sentinel events reported. It is safe and efficacious to use standardized concentrations combined with smart pump technology and abandon the use of the rule of 6 in the pediatric population.

  10. Electrochemical preparation of standard solutions of Pb(II) ions in ionic liquid for analysis of hydrophobic samples: The olive oil case.

    PubMed

    Baldo, M Antonietta; Stortini, Angela M; Moretto, Ligia M; Ongaro, Michael; Roman, Marco; Ugo, Paolo

    2017-09-01

    In this paper we present an electrochemical approach to prepare standard solutions of metal ions in a room temperature ionic liquid (IL), which can find useful application for analysis in hydrophobic matrices. The method, developed here for the case of lead ions, is based on the galvanostatic dissolution of a lead anode dipped directly in a suitable IL, namely tri-hexyl(tetradecyl)phosphonium bis (trifluoromethylsulfonyl) imide ([P14,6,6,6](+)[NTf2](-)). After each oxidation step, the metal dissolution process in the IL solutions was monitored by cyclic voltammetric measurements at a glassy carbon disk electrode. The results indicated that the peak current relevant to the reduction of the electro-generated Pb(II) increased linearly while increasing the oxidation time. By varying the oxidation time from 200 to 6000s, a set of Pb((II))/[P14,6,6,6](+)[NTf2](-) solutions at concentrations ranging between 10 and 300μgg(-1) was prepared. To validate the efficiency of the electrochemical procedure to produce metal ion standard solutions, the Pb content was quantified by developing a microwave digestion procedure specifically suitable for the IL medium, followed by ICP-QMS analysis in the digested standards. The results indicated a satisfactory agreement between concentrations found by ICP-QMS and calculated from electrochemical data, with a coulometric efficiency of Pb(II) generation in ionic liquid ≥95.6%. Finally, the applicability of the Pb((II))/IL solutions as standards for analyses in hydrophobic media was tested by determining, by ICP-QMS, the Pb content in an extra-virgin olive oil spiked with known amounts of a Pb((II))/IL standard. Satisfactory Pb recoveries, ≥96%, were measured. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. An International Marine-Atmospheric 222Rn Measurement Intercomparison in Bermuda Part I: NIST Calibration and Methodology for Standardized Sample Additions

    PubMed Central

    Collé, R.; Unterweger, M. P.; Hodge, P. A.; Hutchinson, J. M. R.

    1996-01-01

    As part of an international 222Rn measurement intercomparison conducted at Bermuda in October 1991, NIST provided standardized sample additions of known, but undisclosed (“blind”) 222Rn concentrations that could be related to U.S. national standards. The standardized sample additions were obtained with a calibrated 226Ra source and a specially-designed manifold used to obtain well-known dilution factors from simultaneous flow-rate measurements. The additions were introduced over sampling periods of several hours (typically 4 h) into a common streamline on a sampling tower used by the participating laboratories for their measurements. The standardized 222Rn activity concentrations for the intercomparison ranged from approximately 2.5 Bq · m−3 to 35 Bq · m−3 (of which the lower end of this range approached concentration levels for ambient Bermudian air) and had overall uncertainties, approximating a 3 standard deviation uncertainty interval, of about 6 % to 13 %. This paper describes the calibration and methodology for the standardized sample additions. PMID:27805090

  12. Potential of electric quadrupole transitions in radium isotopes for single-ion optical frequency standards

    SciTech Connect

    Versolato, O. O.; Wansbeek, L. W.; Jungmann, K.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W.

    2011-04-15

    We explore the potential of the electric quadrupole transitions 7s {sup 2}S{sub 1/2}-6d {sup 2}D{sub 3/2}, 6d {sup 2}D{sub 5/2} in radium isotopes as single-ion optical frequency standards. The frequency shifts of the clock transitions due to external fields and the corresponding uncertainties are calculated. Several competitive {sup A}Ra{sup +} candidates, with A= 223-229, are identified. In particular, we show that the transition 7s {sup 2}S{sub 1/2} (F=2,m{sub F}=0)-6d {sup 2}D{sub 3/2} (F=0,m{sub F}=0) at 828 nm in {sup 223}Ra{sup +}, with no linear Zeeman and electric quadrupole shifts, stands out as a relatively simple case, which could be exploited as a compact, robust, and low-cost atomic clock operating at a fractional frequency uncertainty of 10{sup -17}. With more experimental effort, the {sup 223,225,226}Ra{sup +} clocks could be pushed to a projected performance reaching the 10{sup -18} level.

  13. Stationary solutions for the parity-even sector of the CPT-even and Lorentz-covariance-violating term of the standard model extension

    NASA Astrophysics Data System (ADS)

    Casana, Rodolfo; Ferreira, Manoel M.; Gomes, A. R.; Pinheiro, Paulo R. D.

    2009-08-01

    In this work, we focus on some properties of the parity-even sector of the CPT-even electrodynamics of the standard model extension. We analyze how the six non-birefringent terms belonging to this sector modify the static and stationary classical solutions of the usual Maxwell theory. We observe that the parity-even terms do not couple the electric and magnetic sectors (at least in the stationary regime). The Green’s method is used to obtain solutions for the field strengths E and B at first order in the Lorentz-covariance-violating parameters. Explicit solutions are attained for point-like and spatially extended sources, for which a dipolar expansion is achieved. Finally, an Earth-based experiment is presented that can lead (in principle) to an upper bound on the anisotropic coefficients as stringent as left(widetilde{kappa}_{e-}right)^{ij}<2.9×10^{-20}.

  14. Developing a yearlong Next Generation Science Standard (NGSS) learning sequence focused on climate solutions: opportunities, challenges and reflections

    NASA Astrophysics Data System (ADS)

    Cordero, E.; Centeno, D.

    2015-12-01

    Over the last four years, the Green Ninja Project (GNP) has been developing educational media (e.g., videos, games and online lessons) to help motivate student interest and engagement around climate science and solutions. Inspired by the new emphasis in NGSS on climate change, human impact and engineering design, the GNP is developing a technology focused, integrative, and yearlong science curriculum focused around solutions to climate change. Recognizing the importance of teacher training on the successful implementation of NGSS, we have also integrated teacher professional development into our curriculum. During the presentation, we will describe the design philosophy around our middle school curriculum and share data from a series of classes that are piloting the curriculum during Fall 2015. We will also share our perspectives on how data, media creation and engineering can be used to create educational experiences that model the type of 'three-dimensional learning' encouraged by NGSS.

  15. Standardized Patient Training Programs: an Efficient Solution to the Call for Quality Improvement in Oncologist Communication Skills.

    PubMed

    Ju, Melody; Berman, Abigail T; Vapiwala, Neha

    2015-09-01

    Several key medical and oncologic professional societies have endorsed the importance of physician communication as a quality improvement metric. Despite this clear message, there remain substantial barriers to communication skills training (CST) in oncologic specialties. Herein, we describe the major barriers to communications training and propose standardized patient (SP) programs as efficient and strategic starting points and as expansion opportunities for new and existing CSTs.

  16. Directly Relating Gas-Phase Cluster Measurements to Solution-Phase Hydrolysis, the Absolute Standard Hydrogen Electrode Potential, and the Absolute Proton Solvation Energy

    PubMed Central

    Donald, William A.; Leib, Ryan D.; O’Brien, Jeremy T.; Williams, Evan R.

    2009-01-01

    Solution-phase, half-cell potentials are measured relative to other half-cell potentials, resulting in a thermochemical ladder that is anchored to the standard hydrogen electrode (SHE), which is assigned an arbitrary value of 0 V. A new method for measuring the absolute SHE potential is demonstrated in which gaseous nanodrops containing divalent alkaline-earth or transition-metal ions are reduced by thermally generated electrons. Energies for the reactions 1) M-(H2O)242+(g)+e−(g)→M(H2O)24+(g) and 2) M(H2O)242+(g)+e−(g)→MOH(H2O)23+(g)+H(g) and the hydrogen atom affinities of MOH(H2O)23+(g) are obtained from the number of water molecules lost through each pathway. From these measurements on clusters containing nine different metal ions and known thermochemical values that include solution hydrolysis energies, an average absolute SHE potential of +4.29 V vs. e−(g) (standard deviation of 0.02 V) and a real proton solvation free energy of −265 kcal mol−1 are obtained. With this method, the absolute SHE potential can be obtained from a one-electron reduction of nanodrops containing divalent ions that are not observed to undergo one-electron reduction in aqueous solution. PMID:19440999

  17. [Dynamics of riboflavin level in aqueous humour of anterior chamber of experimental animals under standard stroma saturation by ultraviolet corneal cross-linking solutions].

    PubMed

    Bikbov, M M; Shevchuk, N E; Khalimov, A R; Bikbova, G M

    To evaluate the dynamics of riboflavin changes in the aqueous humour of the anterior chamber (AHAC) of rabbits' eyes during standard ultraviolet (UV) cross-linking with account to the area of corneal debridement. Forty two rabbits were studied sequentially. The following solutions of riboflavin were used for cornea saturation: IR - 0.1% isosmotic riboflavin, D - Dextralink (0.1% riboflavin with 20% dextran), R - 0.1% riboflavin with 1.0% hydroxypropylmethylcellulose (HPMC). Each solution was evaluated in 3 groups that differed in the diameter of corneal debridement: group 1 - Epi-Off 3 mm (IR-3, D-3, P-3), group 2 - Epi-Off 6 mm (IR-6, D-6, R-6), and group 3 - Epi-Off 9 mm (IR-9, D-9, R-9). Aqueous humour sampling (252 samples in total) was performed in 10-minute intervals within a 60 minute period. Riboflavin levels were measured by enzyme-linked immunoassay (ID-Vit microbiological test system; Immundiagnostik, Germany). Stable growth rates of riboflavin level in the AHAC (with maximum values reached at 30-40 min) were observed for solutions D and R, regardless of the variant of corneal debridement. Moreover, throughout the whole follow-up period and regardless of the area of corneal debridement, the solution D provided a relatively lower concentration of riboflavin in the AHAC as compared to the two other solutions. At 30 minutes, when the cornea was considered ready for UV irradiation, the riboflavin level in the AHAC ranged from 385±26.1 μg/l (D-9) to 665±28 μg/l (R-9). In groups IR-9, IR-6, P-6, IR-3, and P-3 riboflavin levels were found to be in the same range starting at 20 minutes. However, even a sufficient concentration of riboflavin in the cornea or AHAC cannot guarantee safe and effective UV cross-linking, since the removed epithelium limits the area of the stroma that can be saturated with riboflavin, while the area of UV exposure is 8-10 mm. Safe and efficient standard UV cross-linking may be performed only under sufficient saturation of the

  18. Aldehydes in hydrothermal solution - Standard partial molal thermodynamic properties and relative stabilities at high temperatures and pressures

    NASA Technical Reports Server (NTRS)

    Schulte, Mitchell D.; Shock, Everett L.

    1993-01-01

    Aldehydes are common in a variety of geologic environments and are derived from a number of sources, both natural and anthropogenic. Experimental data for aqueous aldehydes were taken from the literature and used, along with parameters for the revised Helgeson-Kirkham-Flowers (HKF) equations of state, to estimate standard partial molal thermodynamic data for aqueous straight-chain alkyl aldehydes at high temperatures and pressures. Examples of calculations involving aldehydes in geological environments are given, and the stability of aldehydes relative to carboxylic acids is evaluated. These calculations indicate that aldehydes may be intermediates in the formation of carboxylic acids from hydrocarbons in sedimentary basin brines and hydrothermal systems like they are in the atmosphere. The data and parameters summarized here allow evaluation of the role of aldehydes in the formation of prebiotic precursors, such as amino acids and hydroxy acids on the early Earth and in carbonaceous chondrite parent bodies.

  19. A Singlet Extension of the Minimal Supersymmetric Standard Model: Towards a More Natural Solution to the Little Hierarchy Problem

    SciTech Connect

    de la Puente, Alejandro

    2012-05-01

    In this work, I present a generalization of the Next-to-Minimal Supersymmetric Standard Model (NMSSM), with an explicit μ-term and a supersymmetric mass for the singlet superfield, as a route to alleviating the little hierarchy problem of the Minimal Supersymmetric Standard Model (MSSM). I analyze two limiting cases of the model, characterized by the size of the supersymmetric mass for the singlet superfield. The small and large limits of this mass parameter are studied, and I find that I can generate masses for the lightest neutral Higgs boson up to 140 GeV with top squarks below the TeV scale, all couplings perturbative up to the gauge unification scale, and with no need to fine tune parameters in the scalar potential. This model, which I call the S-MSSM is also embedded in a gauge-mediated supersymmetry breaking scheme. I find that even with a minimal embedding of the S-MSSM into a gauge mediated scheme, the mass for the lightest Higgs boson can easily be above 114 GeV, while keeping the top squarks below the TeV scale. Furthermore, I also study the forward-backward asymmetry in the t¯t system within the framework of the S-MSSM. For this purpose, non-renormalizable couplings between the first and third generation of quarks to scalars are introduced. The two limiting cases of the S-MSSM, characterized by the size of the supersymmetric mass for the singlet superfield is analyzed, and I find that in the region of small singlet supersymmetric mass a large asymmetry can be obtained while being consistent with constraints arising from flavor physics, quark masses and top quark decays.

  20. Determination of acidity constants of sparingly soluble drugs in aqueous solution by the internal standard capillary electrophoresis method.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Rosés, Martí

    2014-12-01

    A set of 33 drugs with different solubilities, ranging from soluble to very insoluble, has been chosen in order to evaluate the performance of the internal standard CE method to determine acidity constants of compounds with limited solubility. The set of drugs tested in this work has been chosen as a function of their intrinsic solubility. For the most insoluble compounds, several analytical conditions to overcome the insolubility in aqueous buffers have been tested. This paper assesses the compound solubility limits for the IS-CE method in aqueous pKa determinations, and also compares the determined pKa s with the results from the literature data obtained by other methods. It is proved that IS-CE method determines acidity constants of sparingly soluble drugs in aqueous media (compounds with logS down to around -6), whereas other reference methods require the use of aqueous-organic solvent buffers and extrapolation procedures to obtain the aqueous pKa for the same compounds.

  1. Thiols in Hydrothermal Solution: Standard Partial Molal Properties and Their Role in the Organic Geochemistry of Hydrothermal Environments

    NASA Technical Reports Server (NTRS)

    Schulte, Mitchell D.; Rogers, Karyn L.; DeVincenzi, D. (Technical Monitor)

    2001-01-01

    Modern seafloor hydrothermal systems are locations where great varieties of geochemistry occur due to the enormous disequilibrium between vent fluids and seawater. The disequilibrium geochemistry has been hypothesized to include reactions to synthesize organic compounds. Despite the incomplete understanding of the carbon budget in hydrothermal systems, the organic geochemistry of these sites has received little attention. Experimental simulations of these environments, however, indicate that organic compounds may have difficulty forming in a purely aqueous environment. On the other hand, thiols, thioesters and disulfides have been implicated as reaction intermediates between CO or CO2 in experiments of carbon reduction in hydrothermal environments, as well as in a variety of biological processes and other abiotic reactions. The reduction of CO2 to thesis, for example, is observed using the FeS-H2S/FeS2 couple to provide the reducing power. We have used recent advances in theoretical geochemistry to estimate the standard partial moral thermodynamic properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for aqueous straight-chain alkyl thesis. With these data and parameters we have evaluated the role that organic sulfur compounds may play as reaction intermediates during organic compound synthesis. We conclude that organic sulfur compounds may hold the key to the organic chemistry leading to the origin of life in hydrothermal settings. These results may also explain the presence of sulfur in a number of biomolecules present in ancient thermophilic microorganisms.

  2. Rheumatology education for undergraduate nursing, physiotherapy and occupational therapy students in the UK: standards, challenges and solutions

    PubMed Central

    Clarke, B.; O’Brien, A.; Hammond, A.; Ryan, S.; Kay, L.; Richards, P.; Almeida, C.

    2008-01-01

    Objectives. Rheumatological conditions are common, thus nurses (Ns) occupational therapists (OTs) and physiotherapists (PTs) require at least basic rheumatology knowledge upon qualifying. The aim of this study was to develop a core set of teaching topics and potential ways of delivering them. Methods. A modified Delphi technique was used for clinicians to develop preliminary core sets of teaching topics for each profession. Telephone interviews with educationalists explored their views on these, and challenges and solutions for delivering them. Inter-professional workshops enabled clinicians and educationalists to finalize the core set together, and generate methods for delivery. Results. Thirty-nine rheumatology clinicians (12N, 14OT, 13PT) completed the Delphi consensus, proposing three preliminary core sets (N71 items, OT29, PT26). Nineteen educationalists (6N, 7OT, 6PT) participated in telephone interviews, raising concerns about disease-specific vs generic teaching and proposing many methods for delivery. Three inter-professional workshops involved 34 participants (clinicians: N12, OT9, PT5; educationalists: N2, OT3, PT2; Patient 1) who reached consensus on a single core set comprising six teaching units: Anatomy and Physiology; Assessment; Management and Intervention; Psychosocial Issues; Patient Education; and the Multi-disciplinary Team, recommending some topics within the units receive greater depth for some professions. An innovative range of delivery options was generated plus two brief interventions: a Rheumatology Chat Show and a Rheumatology Road Show. Conclusions. Working together, clinicians and educationalists proposed a realistic core set of rheumatology topics for undergraduate health professionals. They proposed innovative delivery methods, with collaboration between educationalists, clinicians and patients strongly recommended. These potential interventions need testing. PMID:18443005

  3. A primary standard source of radon-222 based on the HPGe detector.

    PubMed

    Mostafa, M Y A; Vasyanovich, M; Zhukovsky, M

    2017-02-01

    The present paper describes the prototype of a calibration standard system for radon concentrations to be used in establishing the traceability of radon concentration measurements in dwellings. Radon gas was generated with a radium-226 solid source in a certified volume as a closed system. The activity of the radon that was released in the closed system was determined from the difference between the absolute activity of the standard radium solid source and the residual radon decay products ((214)Bi or (214)Pb). A high-purity germanium (HPGe) detector, which was calibrated using gamma reference standard sources, was used to measure the activity of a radium solid source and radon decay products ((214)Bi or (214)Pb). The emanation factor of the (226)Ra source was controlled online with the HPGe detector. Radon activity was achieved at ~1500±45Bq from the radium source at 3.95±0.2kBq under equilibrium conditions. After this activity, the radon gas was transferred into the closed system producing radon activity concentrations of 31.1±0.3kBq/m(3). Systematic errors were found of less than 4% with a random error around 0.5%. The random error is generally associated with the estimation of the count rate of the measured radon progenies ((214)Po and (214)Po for alpha measurements or (214)Pb and (214)Bi for gamma measurements), but systematic errors are associated with the errors introduced by the instrumentation and measurement technique. The system that was developed has a high degree of accuracy and can be recommended as a national or regional prototype standard of radon activity concentration to calibrate different working radon measurement devices.

  4. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Attachment 6, Supplemental standard for Durango processing site. Revised final report

    SciTech Connect

    Not Available

    1991-12-01

    Excavation control to the 15 pCi/g radium-226 (Ra-226) standard at certain areas along the Animas River on the Durango Site would require extensive engineering and construction support. Elevated Ra-226 concentrations have been encountered immediately adjacent to the river at depths in excess of 7 feet below the present river stage. Decontamination to such depths to ensure compliance with the EPA standards will, in our opinion, become unreasonable. This work does not appear to be in keeping with the intent of the standards. Because the principal reason for radium removal is reduction of radon daughter concentrations (RDC) in homes to be built onsite, and because radon produced at depth will be attenuated in clean fill cover before entering such homes, it is appropriate to calculate the depth of excavation needed under a home to reduce RDC to acceptable levels. Potential impact was assessed through radon emanation estimation, using the RAECOM computer model. Elevated Ra-226 concentrations were encountered during final radium excavation of the flood plain below the large tailings pile, adjacent to the slag area. Data from 7 test pits excavated across the area were analyzed to provide an estimate of the Ra-226 concentration profile. Results are given in this report.

  5. A needle-free reconstitution and transfer system for compounded sterile intravenous drug solutions in compliance with United States Pharmacopeia Chapter <797> standards.

    PubMed

    Marks, Zach

    2014-01-01

    Today's health-system pharmacists and those in independent practice face risks, including exposure to potent cytotoxic drugs via needlesticks, that are associated with preparing intravenous compounded sterile preparations for immediate use. Healthcare givers who administer such medications also risk exposure to needlesticks. Those hazards can be minimized when the pharmacist thoroughly understands and complies with current standard operating procedures for preparing intravenous compounded sterile preparations and the healthcare giver uses a needle-free system for drug reconstitution and administration. The components of an overall needlestick risk-reduction strategy to ensure safety in the preparation (and eventual administration) of intravenous compounded sterile preparations should therefore include the use of needle-free connection and administration devices as well as hand-hygiene training, aseptic technique competency evaluation and training, and the maximum use of commercially available or ready-to-use dosage forms. This article, which focuses on the pharmacist's use of a needle-free reconstitution and transfer system for compounded sterile intravenous drug solutions, uses as an example the Vial2Bag (Medimop Medical Projects, Ltd., [a subsidiary of West Pharmaceutical Services, Inc., Exton, Pennsylvania], Ra'anana, Israel), which complies with United States Pharmacopeia Chapter <797> standards. Features of that system are summarized for easy reference.

  6. The Effects of Biocompatible Compared with Standard Peritoneal Dialysis Solutions on Peritonitis Microbiology, Treatment, and Outcomes: the balANZ Trial

    PubMed Central

    Johnson, David W.; Brown, Fiona G.; Clarke, Margaret; Boudville, Neil; Elias, Tony J.; Foo, Marjorie W.Y.; Jones, Bernard; Kulkarni, Hemant; Langham, Robyn; Ranganathan, Dwarakanathan; Schollum, John; Suranyi, Michael G.; Tan, Seng H.; Voss, David

    2012-01-01

    ♦ Background: A multicenter, multi-country randomized controlled trial (the balANZ study) recently reported that peritonitis rates significantly improved with the use of neutral-pH peritoneal dialysis (PD) solutions low in glucose degradation products (“biocompatible”) compared with standard solutions. The present paper reports a secondary outcome analysis of the balANZ trial with respect to peritonitis microbiology, treatment, and outcomes. ♦ Methods: Adult incident PD patients with residual renal function were randomized to receive either biocompatible or conventional (control) PD solutions for 2 years. ♦ Results: The safety population analysis for peritonitis included 91 patients in each group. The unadjusted geometric mean peritonitis rates in those groups were 0.30 [95% confidence interval (CI): 0.22 to 0.41] episodes per patient-year for the biocompatible group and 0.49 (95% CI: 0.39 to 0.62) episodes per patient-year for the control group [incidence rate ratio (IRR): 0.61; 95% CI: 0.41 to 0.90; p = 0.01]. When specific causative organisms were examined, the rates of culture-negative, gram-positive, gram-negative, and polymicrobial peritonitis episodes were not significantly different between the biocompatible and control groups, although the biocompatible group did experience a significantly lower rate of non-pseudomonal gram-negative peritonitis (IRR: 0.41; 95% CI: 0.18 to 0.92; p = 0.03). Initial empiric antibiotic regimens were comparable between the groups. Biocompatible fluid use did not significantly reduce the risk of peritonitis-associated hospitalization (adjusted odds ratio: 0.80; 95% CI: 0.48 to 1.34), but did result in a shorter median duration of peritonitis-associated hospitalization (6 days vs 11 days, p = 0.05). Peritonitis severity was more likely to be rated as mild in the biocompatible group (37% vs 10%, p = 0.001). Overall peritonitis-associated technique failures and peritonitis-related deaths were comparable in the two groups

  7. Thermodynamics of Dilute Solutions.

    ERIC Educational Resources Information Center

    Jancso, Gabor; Fenby, David V.

    1983-01-01

    Discusses principles and definitions related to the thermodynamics of dilute solutions. Topics considered include dilute solution, Gibbs-Duhem equation, reference systems (pure gases and gaseous mixtures, liquid mixtures, dilute solutions), real dilute solutions (focusing on solute and solvent), terminology, standard states, and reference systems.…

  8. Quantification of (226)Ra at environmental relevant levels in natural waters by ICP-MS: Optimization, validation and limitations of an extraction and preconcentration approach.

    PubMed

    Lagacé, François; Foucher, Delphine; Surette, Céline; Clarisse, Olivier

    2017-05-15

    Radium (Ra) at environmental relevant levels in natural waters was determined by ICP-MS after an off-line pre-concentration procedure. The latter consisted of Ra selective elution from potential interfering elements (i.e. other alkaline earth cations: Ba(2+), Sr(2+), Ca(2+), Mg(2+)) on a series of two different ion exchange resins (AG50W-X8 and Sr-resin). The overall analytical method was optimized according to the instrumental performance, the volume of water sample loaded on resins, and the sample salinity. Longer acquisition time (up to 150 s) was required to ensure stable measurement of Ra by ICP-MS at ultra trace level (1.0pgL(-1)). For a synthetic groundwater spiked with Ra at 10.0pgL(-1), the analytical procedure demonstrated efficient separation of the analyte from its potential interfering elements and a complete recovery, independent of the sample volume tested from 10 up to 100mL. For synthetic seawater spiked at a level of 10.0pgL(-1) of Ra, the total load of salts on the two resins should not exceed 0.35g in order to ensure a complete separation and recovery of Ra. The method was validated on natural waters (i.e. groundwater, freshwater and seawater samples) spiked with Ra at different levels (0.0, 0.5, 1.0 and 5.0pgL(-1)). Absolute Ra detection limits were determined at 0.020pgL(-1) (0.73mBqL(-1)) and 0.12pgL(-1) (4.4mBqL(-1)) respectively for 60.0mL of freshwater sample and for 10.0mL of seawater. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Uptake of /sup 226/Ra by established vegetation and black cutworm larvae, Agrotis ipsilon (class Insecta: order Lepidoptera), on U mill tailings at Elliot Lake, Canada

    SciTech Connect

    Clulow, F.V.; Dave, N.K.; Lim, T.P.; Cloutier, N.R.

    1988-07-01

    Radium-226 levels in samples from an inactive U tailings site at Elliot Lake, Ontario, Canada, were: 9140 +/- 500 mBq g-1 dry weight in the substrate; 62 +/- 1 mBq g-1 dry weight in rye, Secale cereale, and less than 3.7 mBq g-1 dry weight in oats, Avena sativa, the dominant species established by revegetation of the tailings; and 117 +/- 7 mBq g-1 dry weight in washed and unwashed black cutworm larvae. Concentration ratios were: vegetation to tailings 0.001-0.007; black cutworms to vegetation 3.6 and black cutworms to tailings 0.01. The values are considered too low to be considered a hazard to herring gulls, Larus argentatus, which occasionally feed on cutworms.

  10. Sampling and Analysis Plan for Investigating the Origin of Natural 226Ra, 228Ra, and 238U in South Carolina Coastal Plain Groundwater

    SciTech Connect

    Millings, M.R.

    2003-04-08

    The objective of this investigation is to obtain baseline data for naturally occurring Ra and U from the water table, Gordon, Crouch Branch, and McQueen Branch Aquifers, which provide drinking water for private and city supply wells in the region. Background wells onsite (P-wells) and nearby offsite wells (C-Wells) will be sampled in this study.

  11. Uptake of 226Ra by established vegetation and black cutworm larvae, Agrotis ipsilon (class Insecta: order Lepidoptera), on U mill tailings at Elliot Lake, Canada.

    PubMed

    Clulow, F V; Davé, N K; Lim, T P; Cloutier, N R

    1988-07-01

    Radium-226 levels in samples from an inactive U tailings site at Elliot Lake, Ontario, Canada, were: 9,140 +/- 500 mBq g-1 dry weight in the substrate; 62 +/- 1 mBq g-1 dry weight in rye, Secale cereale, and less than 3.7 mBq g-1 dry weight in oats, Avena sativa, the dominant species established by revegetation of the tailings; and 117 +/- 7 mBq g-1 dry weight in washed and unwashed black cutworm larvae. Concentration ratios were: vegetation to tailings 0.001-0.007; black cutworms to vegetation 3.6 and black cutworms to tailings 0.01. The values are considered too low to be considered a hazard to herring gulls, Larus argentatus, which occasionally feed on cutworms.

  12. Evaluation of Visualization Using a 50/50 (Contrast Media/Glucose 5% Solution) Technique for Radioembolization as an Alternative to a Standard Sandwich Technique.

    PubMed

    Paprottka, Karolin J; Todica, Andrei; Ilhan, Harun; Rübenthaler, Johannes; Schoeppe, Franziska; Michl, Marlies; Heinemann, Volker; Bartenstein, Peter; Reiser, Maximilian F; Paprottka, Philipp M

    2017-06-05

    Radioembolization (RE) with (90)yttrium ((90)Y) resin microspheres generally employs a sandwich technique with separate sequential administration of contrast medium (CM), followed by vehicle (e.g., glucose 5% [G5] solution), then (90)Y resin microspheres (in G5), then G5, and then CM again to avoid contact of CM and microspheres under fluoroscopic guidance. This study evaluates the visualization quality and safety of a modified sandwich technique with a 50/50-mixture of CM (Imeron 300) and G5 for administration of (90)Y resin microspheres. A retrospective analysis of 81 RE procedures in patients with primary or secondary liver tumors was performed. The quality of angiographic visualization of the hepatic vessels was assessed before the first injection and immediately before the whole dose has been injected. Visualization and flow rate were graded on a 5-point scale: 1 = very good to 5 = not visible/no antegrade flow. Univariate logistic regression models and multiple linear regression models were used to evaluate the prognostic variables associated with visualization and flow scores. Visualization quality was inversely related to flow rate, the lower the flow rate the better the grade of the visualization. Visualization quality was also inversely related to body-mass-index (BMI). Performing RE with the 50/50-CM/G5 mixture resulted in a mean injection time for 1 GBq of 15 min. No clinically significant adverse events, including radiation-induced liver disease were reported. RE with a 50/50-mixture of CM and G5 for administration of (90)Y resin microspheres in a modified sandwich technique is a safe administration alternative and provides good visualization of hepatic vessels, which is inversely dependent on flow rate and BMI. Injection time was reduced compared with our experience with the standard sandwich technique.

  13. Comparison of fresh frozen plasma with a standardized serum protein solution following therapeutic plasma exchange in patients with autoimmune disease: a prospective controlled clinical trial.

    PubMed

    Keller, E; Beeser, H; Peter, H H; Arnold, A; Kotitschke, R

    2000-10-01

    The aim of the study was the comparison of the influence of fresh frozen plasma (FFP) (Freiburg, Germany) and Biseko, Biotest Pharma GmbH (Dreieich, Germany), as a plasma substitute (a standardized, virus inactivated human serum protein solution) on the coagulation factors, inhibitors, proteins, and complement factors in the plasma of autoimmune disease patients following membrane plasma separation. Patients (n = 24) with autoimmune disease were randomized to receive either FFP or Biseko for membrane plasma separation therapy. During each plasma exchange, 100% of the plasma volume was replaced by the respective substitute. Plasma exchange volume was performed once daily for 3 days. Target test parameters of the coagulation system were fibrinogen, fibrinopeptide A, factor VIII (FVIIIC), von Willebrand factor antigen (vWFAg), partial thromboplastin time (PTT), thromboplastin time (Quick value), and antithrombin (AT III). The immunoglobulins were IgG, IgA, and IgM and C-reactive protein (CRP). The thrombocytes were platelet factor 4 (PF4), and complement factors were C3 and C4. Biseko was well tolerated with 1 mild adverse drug reaction (ADR) (n = 1) while FFP gave rise to ADR on 7 occasions (n = 4). Statistically significant differences in the 2 groups were observed for fibrinogen, PTT, Quick value, and AT III. From the clinical point of view, all fluctuations and differences in parameter levels remained clinically silent. The differences had no clinical consequences. Reflecting on a potential decrease in the risk of infections in comparison to FFP therapy and the lower rate of adverse drug reactions, it is possible to postulate an advantage of Biseko for plasma exchange therapy.

  14. Acute intradialytic cardiac function and inflammatory cytokine changes during high-efficiency online hemodiafiltration with acetate-free and standard dialysis solutions.

    PubMed

    Tiranathanagul, Khajohn; Tangvoraphonkchai, Kamonwan; Srisawat, Nattachai; Susantitaphong, Paweena; Tungsanga, Kriang; Praditpornsilpa, Kearkiat; Eiam-Ong, Somchai

    2015-06-01

    Acetate in standard acetate-containing bicarbonate (AC) dialysis fluid could induce peripheral vasodilatation, suppression of myocardial function, and inflammatory cytokine production, resulting in intradialytic hypotension in conventional hemodialysis (HD) patients. Online hemodiafiltration (HDF) provides superior hemodynamic stability over HD. The potentially additive hemodynamic benefits of the novel acetate-free bicarbonate (AF) dialysis fluid in online HDF have never been explored before. The present randomized, double-blind, crossover study was conducted in 22 online HDF patients to investigate the impact of AF dialysis fluid on hemodynamic and cytokine changes compared with AC dialysis fluid in online HDF. The results demonstrated the comparable changes of arterial pressure between AF and AC online HDF. During the study periods, the incidences of composite intradialytic hypotension and other adverse events were not different. The baseline and hourly changes of cardiac index, cardiac output, and peripheral vascular resistance during dialysis were comparable (P=0.534, 0.199, and 0.641, respectively). The percent reductions of NT-proBNP and cTnT were not significantly different (72.6 ± 12.3 vs. 72.6 ± 12.8%, P=0.99 and 35.2 ± 12.8 vs. 36.7 ± 12.0%, P=0.51). The changes of all pro-inflammatory cytokines (IL-2β, IL-6, IL-8, and TNF-α) and anti-inflammatory cytokine (IL-10) during dialysis were comparable between both groups. In conclusion, AF dialysis solution does not offer additional hemodynamic benefit for stable online HDF patients. The hemodynamic stability provided by online HDF might protect the adverse effects of acetate.

  15. Standard enthalpies of formation for L-tyrosine, DL-norleucine, DL-tryptophan, DL-α-alanyl-DL-norleucine, and products of their dissociation in an aqueous solution

    NASA Astrophysics Data System (ADS)

    Kochergina, L. A.; Krutova, O. N.; Damrina, K. V.

    2015-05-01

    Enthalpies of dissolution are determined for a series of crystal amino acids (L-tyrosine, DL-norleucine, and DL-tryptophan) and a DL-α-alanyl-DL-norleucine dipeptide in aqueous solutions of KOH at 298.15 K by means of direct calorimetry. Standard enthalpies of formation are determined for bioligands and products of their dissociation.

  16. Determining partial differential cross sections for low-energy electron photodetachment involving conical intersections using the solution of a Lippmann-Schwinger equation constructed with standard electronic structure techniques.

    PubMed

    Han, Seungsuk; Yarkony, David R

    2011-05-07

    A method for obtaining partial differential cross sections for low energy electron photodetachment in which the electronic states of the residual molecule are strongly coupled by conical intersections is reported. The method is based on the iterative solution to a Lippmann-Schwinger equation, using a zeroth order Hamiltonian consisting of the bound nonadiabatically coupled residual molecule and a free electron. The solution to the Lippmann-Schwinger equation involves only standard electronic structure techniques and a standard three-dimensional free particle Green's function quadrature for which fast techniques exist. The transition dipole moment for electron photodetachment, is a sum of matrix elements each involving one nonorthogonal orbital obtained from the solution to the Lippmann-Schwinger equation. An expression for the electron photodetachment transition dipole matrix element in terms of Dyson orbitals, which does not make the usual orthogonality assumptions, is derived.

  17. Radium migration through clay liners at waste disposal sites.

    PubMed

    Bosco, M E; Cunha, I I; Saito, R T

    2001-02-05

    The migration of 226Ra through the bottom compacted clay liner of the wastewater disposal reservoirs of an industrial plant that processes uranium ore was evaluated. An instrumental method for 226Ra analysis in soils, consisting of detector calibration, the determination of detector counting efficiency, cumulative counting of both background and soil samples in regular counting intervals, and photo-peak smoothing was developed. The 226Ra was analyzed by means of its granddaughter 214Bi, at a photo-peak of 609 keV. The results showed that most of the 226Ra which diffused from the solution into the soil was retained in the upper layer of the sample, and that just a small percentage migrated to the subjacent layers. This methodology is adequate for the assessment of the migration of radionuclides through soil layers and for environmental impact studies related to contamination of soils by radionuclides.

  18. Sorption of radium-226 from oil-production brine by sediments and soils

    USGS Publications Warehouse

    Landa, E.R.; Reid, D.F.

    1983-01-01

    The sorption of226Ra from oil-production brine by soils and sediments was investigated. Sorption was rapid, and the percentage sorbed increased with brine dilution. Greatest removals of226Ra from sediments in the laboratory occurred with alkaline DTPA, HCl, and BaCl2, with lesser removals using CaCl2 and NaCl solutions. Digestion of sediments with NaOCl indicates that most of the native and sorbed226Ra is associated with the mineral rather than organic fraction of the sediments. Correlation analysis based on 14 soils indicates that the retention of226Ra may involve precipitation reactions associated with sulfate-bearing minerals, as well as ion-exchange reactions with the clay mineral fractions of surficial earth materials. ?? 1982 Springer-Verlag New York Inc.

  19. Characterization of the International Humic Substances Society standard and reference fulvic and humic acids by solution state carbon-13 (13C) and hydrogen-1 (1H) nuclear magnetic resonance spectrometry

    USGS Publications Warehouse

    Thorn, Kevin A.; Folan, Daniel W.; MacCarthy, Patrick

    1989-01-01

    Standard and reference samples of the International Humic Substances Society have been characterized by solution state carbon-13 and hydrogen-1 nuclear magnetic resonance (NMR) spectrometry. Samples included the Suwannee River, soil, and peat standard fulvic and humic acids, the Leonardite standard humic acid, the Nordic aquatic reference fulvic and humic acids, and the Summit Hill soil reference humic acid. Aqueous-solution carbon-13 NMR analyses included the measurement of spin-lattice relaxation times, measurement of nuclear Overhauser enhancement factors, measurement of quantitative carbon distributions, recording of attached proton test spectra, and recording of spectra under nonquantitative conditions. Distortionless enhancement by polarization transfer carbon-13 NMR spectra also were recorded on the Suwannee River fulvic acid in deuterated dimethyl sulfoxide. Hydrogen-1 NMR spectra were recorded on sodium salts of the samples in deuterium oxide. The carbon aromaticities of the samples ranged from 0.24 for the Suwannee River fulvic acid to 0.58 for the Leonardite humic acid.

  20. The Influence of Uncompensated Solution Resistance on the Determination and Standard Electrochemical Rate Constants Using Cyclic Voltammetry, and Some Comparisons with AC Voltammetry.

    DTIC Science & Technology

    1987-09-25

    constants, k2ob, using cyclic voltammetry . The results are expressed in terms of systematic deviations of ’apparent measured’ rate constants, k2ob...Keywords: Digital simulation analysis, Uncompensated solution resistance, Electrochemical rate constants, Cyclic voltammetry .

  1. Sequential chemical treatment of radium species in TENORM waste sludge produced from oil and natural gas production.

    PubMed

    El Afifi, E M; Awwad, N S; Hilal, M A

    2009-01-30

    This paper is dedicated to the treatment of sludge occurring in frame of the Egyptian produced from oil and gas production. The activity levels of three radium isotopes: Ra-226 (of U-series), Ra-228 and Ra-224 (of Th-series) in the solid TENORM waste (sludge) were first evaluated and followed by a sequential treatment for all radium species (fractions) presented in TENORM. The sequential treatment was carried out based on two approaches 'A' and 'B' using different chemical solutions. The results obtained indicate that the activity levels of all radium isotopes (Ra-226, Ra-228 and Ra-224) of the environmental interest in the TENORM waste sludge were elevated with regard to exemption levels established by IAEA [International Atomic Energy Agency (IAEA), International basic safety standards for the protection against ionizing radiation and for the safety of radiation sources. GOV/2715/Vienna, 1994]. Each approach of the sequential treatment was performed through four steps using different chemical solutions to reduce the activity concentration of radium in a large extent. Most of the leached radium was found as an oxidizable Ra species. The actual removal % leached using approach B was relatively efficient compared to A. It is observed that the actual removal percentages (%) of Ra-226, Ra-228 and Ra-224 using approach A are 78+/-2.8, 64.8+/-4.1 and 76.4+/-5.2%, respectively. Whereas in approach A, the overall removal % of Ra-226, Ra-228 and Ra-228 was increased to approximately 91+/-3.5, 87+/-4.1 and 90+/-6.2%, respectively.

  2. Development of radon sources with a high stability and a wide range

    SciTech Connect

    Fukutsu, K.; Yamada, Y.

    2013-12-15

    A solid {sup 222}Rn (radon) source using a fibrous and porous SiC ceramic disk was developed. The emission rate of radon emanated from the disk depended on the content of {sup 226}Ra and the sintering temperature. A {sup 226}Ra sulfate ({sup 226}RaSO{sub 4}) solution was dropped on a fibrous SiC ceramic disk (33 mmφ) of 1 mm in thickness, and sintered at 400 °C. The radon concentration from a disk containing {sup 226}Ra of 1.85 MBq was measured to be 38 kBq m{sup −3} at a carrier airflow rate of 0.5 L min{sup −1}. By adjusting the {sup 226}Ra content or the sweep airflow rate, the radon concentrations were easily controlled over a wide range of over three orders of magnitude. The concentration was very stable for a long term. The compactness of the source disk made is easy for handling the source container and the shielding of gamma radiation from {sup 226}Ra and its decay products. Such advantages in a radon generation system are desirable for experiments of high-level, large-scale radon exposure.

  3. Development of radon sources with a high stability and a wide range

    NASA Astrophysics Data System (ADS)

    Fukutsu, K.; Yamada, Y.

    2013-12-01

    A solid 222Rn (radon) source using a fibrous and porous SiC ceramic disk was developed. The emission rate of radon emanated from the disk depended on the content of 226Ra and the sintering temperature. A 226Ra sulfate (226RaSO4) solution was dropped on a fibrous SiC ceramic disk (33 mmϕ) of 1 mm in thickness, and sintered at 400 °C. The radon concentration from a disk containing 226Ra of 1.85 MBq was measured to be 38 kBq m-3 at a carrier airflow rate of 0.5 L min-1. By adjusting the 226Ra content or the sweep airflow rate, the radon concentrations were easily controlled over a wide range of over three orders of magnitude. The concentration was very stable for a long term. The compactness of the source disk made is easy for handling the source container and the shielding of gamma radiation from 226Ra and its decay products. Such advantages in a radon generation system are desirable for experiments of high-level, large-scale radon exposure.

  4. Development of radon sources with a high stability and a wide range.

    PubMed

    Fukutsu, K; Yamada, Y

    2013-12-01

    A solid (222)Rn (radon) source using a fibrous and porous SiC ceramic disk was developed. The emission rate of radon emanated from the disk depended on the content of (226)Ra and the sintering temperature. A (226)Ra sulfate ((226)RaSO4) solution was dropped on a fibrous SiC ceramic disk (33 mmφ) of 1 mm in thickness, and sintered at 400 °C. The radon concentration from a disk containing (226)Ra of 1.85 MBq was measured to be 38 kBq m(-3) at a carrier airflow rate of 0.5 L min(-1). By adjusting the (226)Ra content or the sweep airflow rate, the radon concentrations were easily controlled over a wide range of over three orders of magnitude. The concentration was very stable for a long term. The compactness of the source disk made is easy for handling the source container and the shielding of gamma radiation from (226)Ra and its decay products. Such advantages in a radon generation system are desirable for experiments of high-level, large-scale radon exposure.

  5. The effect of low glucose degradation product, neutral pH versus standard peritoneal dialysis solutions on peritoneal membrane function: the balANZ trial

    PubMed Central

    Johnson, David W.; Brown, Fiona G.; Clarke, Margaret; Boudville, Neil; Elias, Tony J.; Foo, Marjorie W.Y.; Jones, Bernard; Kulkarni, Hemant; Langham, Robyn; Ranganathan, Dwarakanathan; Schollum, John; Suranyi, Michael G.; Tan, Seng H.; Voss, David

    2012-01-01

    Background The balANZ trial recently reported that neutral pH, low glucose degradation product (biocompatible) peritoneal dialysis (PD) solutions significantly delayed anuria and reduced peritonitis rates compared with conventional solutions. This article reports a secondary outcome analysis of the balANZ trial with respect to peritoneal membrane function. Methods Adult, incident PD patients with residual renal function were randomized to receive either biocompatible or conventional (control) PD solutions for 2 years. Peritoneal equilibration tests were performed at 1, 6, 12, 18 and 24 months. Peritoneal small solute clearances and ultra-filtration (UF) were measured at 3, 6, 9, 12, 18 and 24 months. Results Of the 185 patients recruited into the trial, 85 patients in the Balance group and 82 patients in the control group had peritoneal membrane function evaluated. Mean 4-h dialysate:plasma creatinine ratios (D:P Cr 4h) at 1 month were significantly higher in the Balance group compared with controls (0.67 ± 0.10 versus 0.62 ± 0.10, P = 0.002). Over the 2-year study period, mean D:P Cr 4 h measurements remained stable in the Balance group but increased significantly in controls [difference −0.004 per month, 95% confidence interval (95% CI) −0.005 to −0.002, P < 0.001]. Similar results were obtained for dialysate glucose ratios (D/D0 glucose). Peritoneal UF was significantly lower in the Balance group than in controls at 3 and 6 months. Over the 2-year study period, peritoneal UF increased significantly in the Balance group but remained stable in controls (difference 24 mL/day/month, 95% CI 9–39, P = 0.002). No differences in peritoneal small solute clearances, prescribed dialysate fill volumes or peritoneal glucose exposure were observed between the two groups. Conclusions Biocompatible and conventional PD solutions exert differential effects on peritoneal small solute transport rate and UF over time. Adequately powered trials assessing the impact of these

  6. Sonication standard laboratory module

    DOEpatents

    Beugelsdijk, Tony; Hollen, Robert M.; Erkkila, Tracy H.; Bronisz, Lawrence E.; Roybal, Jeffrey E.; Clark, Michael Leon

    1999-01-01

    A standard laboratory module for automatically producing a solution of cominants from a soil sample. A sonication tip agitates a solution containing the soil sample in a beaker while a stepper motor rotates the sample. An aspirator tube, connected to a vacuum, draws the upper layer of solution from the beaker through a filter and into another beaker. This beaker can thereafter be removed for analysis of the solution. The standard laboratory module encloses an embedded controller providing process control, status feedback information and maintenance procedures for the equipment and operations within the standard laboratory module.

  7. Closed-form exact solution to H-infinity optimization of dynamic vibration absorber: II. Development of an algebraic approach and its application to a standard problem

    NASA Astrophysics Data System (ADS)

    Nishihara, Osamu; Asami, Toshihiko

    2000-04-01

    The fixed-points method for the dynamic vibration absorber (DVA) is widely accepted and the results are prevalent for practical applications. However, they usually have to fall back to a heuristic approach from the point of view of its optimization criterion. A typical design problem to minimize the maximum amplitude magnification factor of the primary system, for which the fixed-points method was originally developed, is an example of such common cases. In the present paper, a new algebraic formulation is developed to this classic problem and closed-form exact solutions to both the optimum tuning ratio and the optimum damping parameters are derived, on the assumption of undamped primary system. This algebraic approach is based on an observation of trade-off between two resonance amplitude magnification factors. Thus, the problem reduces to a solution of an algebraic equation, which is derived as a discriminant of quartic algebraic equation. In undamped case, it was proven that the optimum parameters, the minimum amplitude magnification factor, the resonance and antiresonance frequencies, and sensitivities of the amplitude magnification factors are totally algebraic. A numerical extension enables efficient solutions for the damped primary system and has more direct applicability.

  8. Indigenous technology development and standardization of the process for obtaining ready to use sterile sodium pertechnetate-Tc-99m solution from Geltech generator.

    PubMed

    Sarkar, Sishir Kumar; Kothalkar, Chetan; Naskar, Prabhakar; Joshi, Sangeeta; Saraswathy, Padmanabhan; Dey, Arun Chandra; Vispute, Gunvant Leeladhar; Murhekar, Vishwas Vinayak; Pilkhwal, Neelam

    2013-04-01

    The indigenous design and technology development for processing large scale zirconium molybdate-Mo-99 (ZrMo-99) Geltech generator was successfully commissioned in Board of Radiation and Isotope Technology (BRIT), India, in 2006. The generator production facility comprises of four shielded plant facilities equipped with tongs and special process gadgets amenable for remote operations for radiochemical processing of ZrMo-99 gel. Over 2800 Geltech generators have been processed and supplied to user hospitals during the period 2006-2013. Geltech generator supplied by BRIT was initially not sterile. Simple elution of Tc-99m is performed by a sterile evacuated vial with sterile and pyrogen free 0.9% NaCl solution to obtain sodium (Tc-99m) pertechnetate solution. A special type online 0.22 μm membrane filter has been identified and adapted in Geltech generator. The online filtration of Tc-99m from Geltech generator; thus, provided sterile Tc-99m sodium pertechnetate solution. Generators assembled with modified filter assembly were supplied to local hospital in Mumbai Radiation Medicine Centre (RMC) and S.G.S. Medical College and KEM Hospital) and excellent performances were reported by users.

  9. Indigenous technology development and standardization of the process for obtaining ready to use sterile sodium pertechnetate-Tc-99m solution from Geltech generator

    PubMed Central

    Sarkar, Sishir Kumar; Kothalkar, Chetan; Naskar, Prabhakar; Joshi, Sangeeta; Saraswathy, Padmanabhan; Dey, Arun Chandra; Vispute, Gunvant Leeladhar; Murhekar, Vishwas Vinayak; Pilkhwal, Neelam

    2013-01-01

    Purpose of the Study: The indigenous design and technology development for processing large scale zirconium molybdate-Mo-99 (ZrMo-99) Geltech generator was successfully commissioned in Board of Radiation and Isotope Technology (BRIT), India, in 2006. The generator production facility comprises of four shielded plant facilities equipped with tongs and special process gadgets amenable for remote operations for radiochemical processing of ZrMo-99 gel. Results: Over 2800 Geltech generators have been processed and supplied to user hospitals during the period 2006-2013. Geltech generator supplied by BRIT was initially not sterile. Simple elution of Tc-99m is performed by a sterile evacuated vial with sterile and pyrogen free 0.9% NaCl solution to obtain sodium (Tc-99m) pertechnetate solution. A special type online 0.22 μm membrane filter has been identified and adapted in Geltech generator. Conclusions: The online filtration of Tc-99m from Geltech generator; thus, provided sterile Tc-99m sodium pertechnetate solution. Generators assembled with modified filter assembly were supplied to local hospital in Mumbai Radiation Medicine Centre (RMC) and S.G.S. Medical College and KEM Hospital) and excellent performances were reported by users. PMID:24163509

  10. A new technique for the deposition of standard solutions in total reflection X-ray fluorescence spectrometry (TXRF) using pico-droplets generated by inkjet printers and its applicability for aerosol analysis with SR-TXRF

    NASA Astrophysics Data System (ADS)

    Fittschen, U. E. A.; Hauschild, S.; Amberger, M. A.; Lammel, G.; Streli, C.; Förster, S.; Wobrauschek, P.; Jokubonis, C.; Pepponi, G.; Falkenberg, G.; Broekaert, J. A. C.

    2006-11-01

    A new technique for the deposition of standard solutions on particulate aerosol samples using pico-droplets for elemental determinations with total reflection X-ray fluorescence spectrometry (TXRF) is described. It enables short analysis times without influencing the sample structure and avoids time consuming scanning of the sample with the exciting beam in SR-TXRF analysis. Droplets of picoliter volume (˜ 5-130 pL) were generated with commercially available and slightly modified inkjet printers operated with popular image processing software. The size of the dried droplets on surfaces of different polarity namely silicone coated and untreated quartz reflectors, was determined for five different printer types and ten different cartridge types. The results show that droplets generated by inkjet printers are between 50 and 200 μm in diameter (corresponding to volumes of 5 to 130 pL) depending on the cartridge type, which is smaller than the width of the synchrotron beam used in the experiments (< 1 mm at an energy of 17 keV at the beamline L at HASYLAB, Hamburg). The precision of the printing of a certain amount of a single element standard solution was found to be comparable to aliquoting with micropipettes in TXRF, where for 2.5 ng of cobalt relative standard deviations of 12% are found. However, it could be shown that the printing of simple patterns is possible, which is important when structured samples have to be analysed.

  11. Treasure of the Past VI: Standard Potential of the Silver-Silver-Chloride Electrode from 0° to 95° C and the Thermodynamic Properties of Dilute Hydrochloric Acid Solutions.

    PubMed

    Bates, R G; Bower, V E

    2001-01-01

    From electromotive-force measurements of the cell without liquid junction: [Formula: see text]through the range 0° to 95° C, calculations have been made of (1) the standard potential of the silver-silver-chloride electrode, (2) the activity coefficient of hydrochloric acid in aqueous solutions from m (molality) =0 to m=0.1 and from 0° to 90° C, (3) the relative partial molal heat content of hydrochloric acid, and (4) the relative partial molal heat capacity of hydrochloric acid. The extrapolations were made by the method of least squares with the aid of punch-card techniques. Data from at least 24 cells were analyzed at each temperature, and 81 cells were studied at 25° C. The value of the standard potential was found to be 0.22234 absolute volt at 25° C, and the standard deviation was 0.02 millivolt at 0° C, 0.01 millivolt at 25° C, and 0.09 millivolt at 95° C. The results from 0° to 60° C are compared with earlier determinations of the standard potential and other quantities derived from the electromotive force.

  12. Treasure of the Past VI: Standard Potential of the Silver-Silver-Chloride Electrode from 0° to 95° C and the Thermodynamic Properties of Dilute Hydrochloric Acid Solutions

    PubMed Central

    Bates, Roger G.; Bower, Vincent E.

    2001-01-01

    From electromotive-force measurements of the cell without liquid junction: Pt;H2,HCl(m),AgCl;Agthrough the range 0° to 95° C, calculations have been made of (1) the standard potential of the silver–silver-chloride electrode, (2) the activity coefficient of hydrochloric acid in aqueous solutions from m (molality) =0 to m=0.1 and from 0° to 90° C, (3) the relative partial molal heat content of hydrochloric acid, and (4) the relative partial molal heat capacity of hydrochloric acid. The extrapolations were made by the method of least squares with the aid of punch-card techniques. Data from at least 24 cells were analyzed at each temperature, and 81 cells were studied at 25° C. The value of the standard potential was found to be 0.22234 absolute volt at 25° C, and the standard deviation was 0.02 millivolt at 0° C, 0.01 millivolt at 25° C, and 0.09 millivolt at 95° C. The results from 0° to 60° C are compared with earlier determinations of the standard potential and other quantities derived from the electromotive force. PMID:27500034

  13. Design and implementation of an informed consent process for a standardized health information exchange solution on the example of the lower saxony bank of health.

    PubMed

    Schwartze, Jonas; Haarbrandt, Birger; Rochon, Maike; Wagner, Markus; Haux, Reinhold; Kleinschmidt, Thorsten; Plischke, Maik; Seidel, Christoph

    2013-01-01

    Multicenter medical treatment requires health related data to be available across institutions. Since health information exchange solutions are emergent, fulfillment of privacy needs, including patients' informed consent, is vital for successful data exchange. We designed a software supported consent process for the recently founded Lower Saxony Bank of Health (LSBH) with regard to particularities of German law. To implement the application, web technologies and well-described interfaces to IHE XDS profile components have been used. A two staged process has been developed. A special consent application creates a customized form containing all orally given constraints defined by the patient. The form is printed out and signed by the patient while an electronic policy is created and registered at the LSBH. The process completely reflects a conventional informed consent procedure but increases simplicity, clarity and understandability of the consent form. Technical and legal restrictions in Germany create a media split becoming a media crack in some environments. Availability of signature cards could improve the process by making it completely electronic.

  14. Practical solution for control of the pre-analytical phase in decentralized clinical laboratories for meeting the requirements of the medical laboratory accreditation standard DIN EN ISO 15189.

    PubMed

    Vacata, Vladimir; Jahns-Streubel, Gerlinde; Baldus, Mirjana; Wood, William Graham

    2007-01-01

    This report was written in response to the article by Wood published recently in this journal. It describes a practical solution to the problems of controlling the pre-analytical phase in the clinical diagnostic laboratory. As an indicator of quality in the pre-analytical phase of sample processing, a target analyte was chosen which is sensitive to delay in centrifugation and/or analysis. The results of analyses of the samples sent by satellite medical practitioners were compared with those from an on-site hospital laboratory with a controllable optimized pre-analytical phase. The aim of the comparison was: (a) to identify those medical practices whose mean/median sample values significantly deviate from those of the control situation in the hospital laboratory due to the possible problems in the pre-analytical phase; (b) to aid these laboratories in the process of rectifying these problems. A Microsoft Excel-based Pre-Analytical Survey tool (PAS tool) has been developed which addresses the above mentioned problems. It has been tested on serum potassium which is known to be sensitive to delay and/or irregularities in sample treatment. The PAS tool has been shown to be one possibility for improving the quality of the analyses by identifying the sources of problems within the pre-analytical phase, thus allowing them to be rectified. Additionally, the PAS tool has an educational value and can also be adopted for use in other decentralized laboratories.

  15. Standards not that standard.

    PubMed

    Vilanova, Cristina; Tanner, Kristie; Dorado-Morales, Pedro; Villaescusa, Paula; Chugani, Divya; Frías, Alba; Segredo, Ernesto; Molero, Xavier; Fritschi, Marco; Morales, Lucas; Ramón, Daniel; Peña, Carlos; Peretó, Juli; Porcar, Manuel

    2015-01-01

    There is a general assent on the key role of standards in Synthetic Biology. In two consecutive letters to this journal, suggestions on the assembly methods for the Registry of standard biological parts have been described. We fully agree with those authors on the need of a more flexible building strategy and we highlight in the present work two major functional challenges standardization efforts have to deal with: the need of both universal and orthogonal behaviors. We provide experimental data that clearly indicate that such engineering requirements should not be taken for granted in Synthetic Biology.

  16. A low-cost solution to measure mouse licking in an electrophysiological setup with a standard analog-to-digital converter.

    PubMed

    Hayar, Abdallah; Bryant, Jeri L; Boughter, John D; Heck, Detlef H

    2006-06-15

    Licking behavior in rodents is widely used to determine fluid consumption in various behavioral contexts and is a typical example of rhythmic movement controlled by internal pattern-generating mechanisms. The measurement of licking behavior by commercially available instruments is based on either tongue protrusion interrupting a light beam or on an electrical signal generated by the tongue touching a metal spout. We report here that licking behavior can be measured with high temporal precision by simply connecting a metal sipper tube to the input of a standard analog/digital (A/D) converter and connecting the animal to ground (via a metal cage floor). The signal produced by a single lick consists of a 100-800 mV dc voltage step, which reflects the metal-to-water junction potential and persists for the duration of the tongue-spout contact. This method does not produce any significant electrical artifacts and can be combined with electrophysiological measurements of single unit activity from neurons involved in the control of the licking behavior.

  17. Polyacrylamido-2-methyl-1-propane sulfonic acid-grafted-natural rubber as bio-adsorbent for heavy metal removal from aqueous standard solution and industrial wastewater.

    PubMed

    Phetphaisit, Chor Wayakron; Yuanyang, Siriwan; Chaiyasith, Wipharat Chuachuad

    2016-01-15

    Bio-adsorbent modified natural rubber (modified NR) was prepared, by placing the sulfonic acid functional group on the isoprene chain. This modification was carried out with the aim to prepare material capable to remove heavy metals from aqueous solution. The structures of modified NR materials were characterized by FT-IR and NMR spectroscopies. Thermal gravimetric analysis of modified NR showed that the initial degradation temperature of rubber decreases with increasing amount of polyacrylamido-2-methyl-1-propane sulfonic acid (PAMPS) in the structure. In addition, water uptake of the rubber based materials was studied as a function of time and content of PAMPS. The influence of the amount of PAMPS grafted onto NR, time, pH, concentration of metal ions, temperature, and regeneration were studied in terms of their influence on the adsorption of heavy metals (Pb(2+), Cd(2+) and Cu(2+)). The adsorption isotherms of Pb(2+) and Cd(2+) were fitted to the Freundlich isotherm model, while Cu(2+) was fitted to the Langmuir isotherm. However, the results from these two isotherms resulted in a similar behavior. The adsorption capacity of the modified NR for the various heavy metals was in the following order: Pb(2+)∼Cd(2+)>Cu(2+). The maximum adsorption capacities of Pb(2+), Cd(2+), and Cu(2+) were 272.7, 267.2, and 89.7 mg/g of modified rubber, respectively. Moreover, the modified natural rubber was used for the removal of metal ions in real samples of industrial effluents where the efficiency and regeneration were also investigated.

  18. Quantitative Analysis of Trace Elements in Silicate Glass Sample by LA-ICP-QMS/QMS with an ORC: Silicon as the Matrix of Calibrating Solutions and the Internal Standard for Measurement.

    PubMed

    Zhu, Yanbei

    2016-01-01

    A strategy was presented for quantitative analysis of trace elements in a glass sample by laser ablation inductively coupled plasma tandem quadrupole mass spectrometry (LA-ICP-QMS/QMS) with an octapole reaction cell (ORC). Silicon in the glass was used as the internal standard as well as the matrix for making the calibrating solutions. Sample aerosols generated by the laser ablation system were introduced into the dual pass spray chamber through the make-up gas port. Calibrating solutions were nebulized into the spray chamber using a microflow nebulizer. The silicon matrix-matched calibrating solutions produced a calibration curve capable for the quantitative analysis of trace elements in a silicate glass sample, NIST SRM 612. The analytical results agreed with the certified values, taking into consideration their expanded uncertainties. The detection limits for Cr, Mn, Fe, Ni, Cu, As, Sr, Ag, Cd, Sb, Ba, and Pb, were respectively 0.3, 0.08, 0.5, 0.4, 0.19, 1.1, 0.1, 0.02, 0.03, 0.025, 0.09, and 0.07 μg g(-1).

  19. Emergency Radiobioassay Method for Determination of ⁹⁰Sr and ²²⁶Ra in a Spot Urine Sample.

    PubMed

    Sadi, Baki B; Fontaine, Allison; McAlister, Daniel; Li, Chunsheng

    2015-08-04

    A new radiobioassay method has been developed for simultaneous determination of (90)Sr and (226)Ra in a spot urine sample. The method is based on a matrix removal procedure to purify the target radionuclides from a urine sample followed by an automated high performance ion chromatographic (HPIC) separation of (90)Sr and (226)Ra and offline radiometric detection by liquid scintillation counting (LSC). A Sr-resin extraction chromatographic cartridge was used for matrix removal and purification of (90)Sr and (226)Ra from a urine sample prior to its introduction to the HPIC system. The HPIC separation was carried out through cation exchange chromatography using methanesulfonic acid (75 mM) as the mobile phase at 0.25 mL/min flow rate. The performance criteria of the method was evaluated against the American National Standard Institute ANSI/HPS N13.30-2011 standard for the root mean squared error (RMSE) of relative bias (Br) and relative precision (SB) at two different spiked activity levels. The RMSE of Br and SB for (90)Sr and (226)Ra were found to be satisfactory (≤0.25). The minimum detectable activity (MDA) of the method for (90)Sr and (226)Ra are 2 Bq/L and 0.2 Bq/L, respectively. The MDA values are at least 1/10th of the concentrations of (90)Sr (190 Bq/L) and (226)Ra (2 Bq/L) excreted in urine on the third day following an acute exposure (inhalation) that would lead to an effective dose of 0.1 Sv in the first year. The sample turnaround time is less than 8 h for simultaneous determination of (90)Sr and (226)Ra.

  20. Recovery of NORM from scales generated by oil extraction.

    PubMed

    Al Attar, Lina; Safia, Bassam; Ghani, Basem Abdul; Al Abdulah, Jamal

    2016-03-01

    Scales, containing naturally occurring radioactive materials (NORM), are a major problem in oil production that lead to costly remediation and disposal programmes. In view of environmental protection, radio and chemical characterisation is an essential step prior to waste treatment. This study focuses on developing of a protocol to recover (226)Ra and (210)Pb from scales produced by petroleum industry. X-ray diffractograms of the scales indicated the presence of barite-strontium (Ba0.75Sr0.25SO4) and hokutolite (Ba0.69Pb0.31SO4) as main minerals. Quartz, galena and Ca2Al2SiO6(OH)2 or sphalerite and iron oxide were found in minor quantities. Incineration to 600 °C followed by enclosed-digestion and acid-treatment gave complete digestion. Using (133)Ba and (210)Pb tracers as internal standards gave recovery ranged 87-91% for (226)Ra and ca. 100% for (210)Pb. Radium was finally dissolved in concentrated sulphuric acid, while (210)Pb dissolved in the former solution as well as in 8 M nitric acid. Dissolving the scales would provide better estimation of their radionuclides contents, facilitate the determination of their chemical composition, and make it possible to recycle NORM wastes in terms of radionuclides production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Immunoassay standardization.

    PubMed

    Ekins, R

    1991-01-01

    Assays employed in the biological sciences fall into two categories, which may be respectively termed "comparative" (or "functionally-specific") and "analytical" (or "structurally-specific"). The former are intended to compare the relative effects of substances, or mixtures of substances--not necessarily of identical chemical structure--on a biological system (e.g. whole animal, tissue, cell, etc). Results are represented by units of effect (i.e. they are not units of "amount" of the substance(s) measured), and differ depending on the biological system used. Such assays cannot be "standardised" by the use of a calibrant. In contrast, analytical assays are intended to measure the number of molecules (or mass) of a single substance of unique chemical structure in a test sample, and cannot legitimately be employed to measure mixtures of substances of different structure. Results are represented by units of molecular number or mass, and should be identical for any test sample irrespective of the assay system used. Immunoassays generally fall into this category. Insofar as the antigenic substances present in standards or test samples are dissimilar and/or molecularly heterogeneous, an immunoassay is invalid, and the results it yields have no universal significance. Attempts to standardize "analytically-invalid" immunoassays inevitably fail. Many substances of biological interest (e.g. TSH)--initially defined in terms of their biological function--have subsequently been shown to be molecularly heterogenous. Problems thus arise in the standardization of immunoassays used for their measurement, reflecting the fact that the measurement of a mixture of substances of differing molecular structure (and function) is a meaningless concept. It is thus impossible to "measure TSH"; it is only possible to measure the effect TSH exerts in a particularly assay system. The only long-term solution to this problem is the development of assay systems measuring individual components of

  2. Treatment of NORM contaminated soil from the oilfields.

    PubMed

    Abdellah, W M; Al-Masri, M S

    2014-03-01

    Uncontrolled disposal of oilfield produced water in the surrounding environment could lead to soil contamination by naturally occurring radioactive materials (NORM). Large volumes of soil become highly contaminated with radium isotopes ((226)Ra and (228)Ra). In the present work, laboratory experiments have been conducted to reduce the activity concentration of (226)Ra in soil. Two techniques were used, namely mechanical separation and chemical treatment. Screening of contaminated soil using vibratory sieve shaker was performed to evaluate the feasibility of particle size separation. The fractions obtained were ranged from less than 38 μm to higher than 300 μm. The results show that (226)Ra activity concentrations vary widely from fraction to fraction. On the other hand, leaching of (226)Ra from soil by aqueous solutions (distilled water, mineral acids, alkaline medias and selective solvents) has been performed. In most cases, relatively low concentrations of radium were transferred to solutions, which indicates that only small portions of radium are present on the surface of soil particles (around 4.6%), while most radium located within soil particles; only concentrated nitric acid was most effective where 50% of (226)Ra was removed to aqueous phase. However, mechanical method was found to be easy and effective, taking into account safety procedures to be followed during the implementation of the blending and homogenization. Chemical extraction methods were found to be less effective. The results obtained in this study can be utilized to approach the final option for disposal of NORM contaminated soil in the oilfields.

  3. NDTA narcotics standard development

    NASA Astrophysics Data System (ADS)

    Ulvick, Sydney J.; Cui, Jing; Kunz, Terry D.; Hoglund, David E.; Pilon, Pierre; Lawrence, Andre H.; Drolet, Gerry; Su, Chih-Wu; Rigdon, Stephen W.; Demirgian, Jack C.; Shier, Patrick

    1997-01-01

    The Narcotics Detection Technology Assessment (NDTA) program is a series of studies conducted to evaluate illicit substance detection devices. The ability to effectively detect cocaine and heroin particles is directly related to the efficiency of a detection device's sample collection design. The NDTA tests are therefore structured to require sampling of narcotics from a surface. Tests standards are required which permit subnanogram to microgram quantities of narcotic to be dispensed onto a target surface for sampling. Optimally, the standard should not adversely affect the performance of the device under test. The NDTA test team has developed and experimentally characterized solution- deposited substrate standards, solution-deposited substrate- free standards, vapor-deposited standards, suspension standards, and dry mix standards, and dry mix standards. A variety of substrates and dry-mix fillers have been evaluated, including sand, fullerenes, copper powder, nickel powder, pulverized paper, and aluminum. Suspension standards were explored with a variety of liquids. The narcotic standards with the best performance were found to be dry mixes of cocaine with silver-coated nickel powder, and dry mixes of heroin with silanized glass beads.

  4. An alternative method for Ra determinations in water.

    PubMed

    Loyd, D H; Drake, E N

    1989-07-01

    Concentrations of 226Ra and 224Ra in 13 wells distributed throughout McCulloch and Mason counties in the Hickory Aquifer of the Llano Uplift Region of West-Central Texas are reported. Measurable alpha-particle activity is present in all wells, with seven wells having 226Ra radioactivity concentrations greater than 185 Bq m-3 (5 pCi L-1). An alternative methodology for measuring 226Ra, 224Ra and 228Ra is described. The EPA-approved methodology for estimating total Ra is shown to be invalid for aquifers containing significant levels of 224Ra. Alpha-particle activity measurements made in the interval of 12 to 300 h after Ra isolation lead to self-consistent solutions for radioactivity concentrations of 226Ra and 224Ra, with negligible contributions from 228Ra. Radioactivity concentrations of 228Ra can be calculated from grow-in terms for this isotope used with alpha-particle activity measurements at post-isolation times significantly longer than 800 h. Comparison of the 226Ra radioactivity concentration with that reported previously by the Texas Department of Health for a single well indicates acceptable agreement. However, the radioactivity concentration attributable to 228Ra for the same well was found to be in significant disagreement with the Texas Department of Health value.

  5. An alternative method for Ra determinations in water

    SciTech Connect

    Loyd, D.H.; Drake, E.N. 2d.

    1989-07-01

    Concentrations of /sup 226/Ra and /sup 224/Ra in 13 wells distributed throughout McCulloch and Mason counties in the Hickory Aquifer of the Llano Uplift Region of West-Central Texas are reported. Measurable alpha-particle activity is present in all wells, with seven wells having /sup 226/Ra radioactivity concentrations greater than 185 Bq m-3 (5 pCi L-1). An alternative methodology for measuring /sup 226/Ra, /sup 224/Ra and /sup 228/Ra is described. The EPA-approved methodology for estimating total Ra is shown to be invalid for aquifers containing significant levels of /sup 224/Ra. Alpha-particle activity measurements made in the interval of 12 to 300 h after Ra isolation lead to self-consistent solutions for radioactivity concentrations of /sup 226/Ra and /sup 224/Ra, with negligible contributions from /sup 228/Ra. Radioactivity concentrations of /sup 228/Ra can be calculated from grow-in terms for this isotope used with alpha-particle activity measurements at post-isolation times significantly longer than 800 h. Comparison of the /sup 226/Ra radioactivity concentration with that reported previously by the Texas Department of Health for a single well indicates acceptable agreement. However, the radioactivity concentration attributable to /sup 228/Ra for the same well was found to be in significant disagreement with the Texas Department of Health value.

  6. Dissolution of [²²⁶Ra]BaSO₄ and partial separation of ²²⁶Ra from radium/barium sulfate: A new treatment method for NORM waste from petroleum industry.

    PubMed

    Al Abdullah, Jamal; Al Masri, M S; Amin, Yusr

    2016-01-01

    Complete dissolution of [(226)Ra]BaSO4 precipitate was successfully performed using NaNO2 as a reducing agent in acidic solution at room temperature. Results showed a significant effect of acid and NaNO2 concentrations and temperature on the dissolution efficiency. The method was successfully used for separation of radium from NORM scale samples from the petroleum industry; sufficient volume reduction of NORM waste was achieved. The obtained (226)Ra solution was purified using two separation methods. The dissolution method can be of great interest in the development of radiochemical analysis of radium isotopes.

  7. Solute atmospheres at dislocations

    DOE PAGES

    Hirth, John P.; Barnett, David M.; Hoagland, Richard G.

    2017-06-01

    In this study, a two-dimensional plane strain elastic solution is determined for the Cottrell solute atmosphere around an edge dislocation in an infinitely long cylinder of finite radius (the matrix), in which rows of solutes are represented by cylindrical rods with in-plane hydrostatic misfit (axial misfit is also considered). The periphery of the matrix is traction-free, thus introducing an image solute field which generates a solute-solute interaction energy that has not been considered previously. The relevant energy for the field of any distribution of solutes coexistent with a single edge dislocation along the (matrix) cylinder axis is determined, and coherencymore » effects are discussed and studied. Monte Carlo simulations accounting for all pertinent interactions over a range of temperatures are found to yield solute distributions different from classical results, namely, (1) Fermi-Dirac condensations at low temperatures at the free surface, (2) the majority of the atmosphere lying within an unexpectedly large non-linear interaction region near the dislocation core, and (3) temperature-dependent asymmetrical solute arrangements that promote bending. The solute distributions at intermediate temperatures show a 1/r dependence in agreement with previous linearized approximations. With a standard state of solute corresponding to a mean concentration, c0, the relevant interaction energy expression presented in this work is valid when extended to large concentrations for which Henry's Law and Vegard's Law do not apply.« less

  8. EFFECTIVENESS AND SAFETY OF 2-HOURLY 20 MCG ORAL MISOPROSTOL SOLUTION COMPARED TO STANDARD INTRAVENOUS OXYTOCIN IN LABOUR INDUCTION DUE TO PRE-LABOUR RUPTURE OF MEMBRANES AT TERM: A RANDOMISED CLINICAL TRIAL AT KENYATTA NATIONAL HOSPITAL.

    PubMed

    Mbaluka, C M; Kamau, K; Karanja, J G; Mugo, N

    2014-09-01

    Pre-labour rupture of membranes (PROM) at term is a common event whose management varies from centre to centre. The practice at the Kenyatta National Hospital (KNH) for patients with PROM at term is to initiate delivery of the patient soon on admission with intravenous oxytocin, if there are no contraindications to vaginal delivery. However, in PROM at term, if the cervix is not ripe, vaginal administration of prostaglandin pessaries for cervical ripening is not possible when there is active draining of liquor, thus use of intravenous oxytocin may take a very long time or fail all together. Oral misoprostol at low doses has been found to be a safe and effective agent for labour induction in numerous studies carried out in the developed world, where there are better resources for monitoring of labour. None of the studies has been carried out in Kenya, a limited resource country. Therefore, there is a need to determine the effectiveness and safety of oral misoprostol solution at the KNH, a limited resource set up. To determine the effectiveness and safety of 2-hourly 20 mcg oral misoprostol solution compared to the standard intravenous oxytocin in labour induction in mothers with pre-labour rupture of membranes at term at the Kenyatta National Hospital. An unblinded randomised clinical trial. Kenyatta National Hospital Labour Ward Unit. Eighty three pregnant women with pre-labour rupture of membranes at term without an indication for Caeserian section were consented and randomised for labour induction with either oral misoprostol at a dose of 20mcg 2-hourly up to a maximum of 4-doses, or with intravenous oxytocin according to the WHO protocol. Induction to delivery interval; maternal complications and early neonatal outcomes. The overall induction success rates in the misoprostol arm was 81% versus 83% in the oxytocin arm (P = 0.447). The mean induction to vaginal delivery interval in the misoprostol arm was 8.4 hours as compared to 9.45 hours in the oxytocin arm (P

  9. Standard Procedure.

    ERIC Educational Resources Information Center

    Uher, Alan E.

    Whether common standards exist among the national standards for kindergarten through grade 12 mathematics, science, and civics and government was studied. Common standards were explored among "Curriculum and Evaluation Standards for School Mathematics," produced by the National Council of Teachers of Mathematics, the "National…

  10. Natural radioactivity in phosphates, phosphogypsum and natural waters in Morocco.

    PubMed

    Azouazi, M; Ouahidi, Y; Fakhi, S; Andres, Y; Abbe, J C; Benmansour, M

    2001-01-01

    The contents of natural radionuclides (uranium, actinium and thorium series) were measured in sedimentary phosphate rock samples using high-resolution gamma spectrometry. Data obtained for uranium content (ppm) were compared with the results obtained by a method based on the measurements using solid-state nuclear track detectors (SSNTD) in the same samples. The potential leaching of radionuclides from sedimentary phosphate rock during the industrial production of the phosphoric acid was studied. The process of leaching of the radioisotopes from phosphogypsum was discussed. A method for the direct alpha counting of 226Ra thin source, elaborated by the deposition of Ra from aqueous solutions on manganese oxides film deposited on polyvinyl support, have been developed and applied for the determination of 226Ra in natural water samples. The results show that only the water sample from the mine area reveals the presence of 226Ra at a level of about 0.2 Bq l-1.

  11. A new application of micellar liquid chromatography in the determination of free ampicillin concentration in the drug-human serum albumin standard solution in comparison with the adsorption method.

    PubMed

    Stępnik, Katarzyna E; Malinowska, Irena; Maciejewska, Małgorzata

    2016-06-01

    The determination of free drug concentration is a very important issue in the field of pharmacology because only the unbound drug fraction can achieve a pharmacological effect. Due to the ability to solubilize many different compounds in micellar aggregates, micellar liquid chromatography (MLC) can be used for direct determination of free drug concentration. Proteins are not retained on the stationary phase probably due to the formation of protein - surfactant complexes which are excluded from the pores of stationary phase. The micellar method is simple and fast. It does not require any pre-preparation of the tested samples for analysis. The main aim of this paper is to demonstrate a completely new applicability of the analytical use of MLC concerning the determination of free drug concentration in the standard solution of human serum albumin. The well-known adsorption method using RP-HPLC and the spectrophotometric technique was applied as the reference method. The results show that the free drug concentration value obtained in the MLC system (based on the RP-8 stationary phase and CTAB) is similar to that obtained by the adsorption method: both RP-HPLC (95.83μgmL(-1), 79.86% of free form) and spectrophotometry (95.71μgmL(-1), 79.76%). In the MLC the free drug concentration was 93.98μgmL(-1) (78.3%). This indicates that the obtained results are within the analytical range of % of free ampicillin fraction and the MLC with direct sample injection can be treated like a promising method for the determination of free drug concentration.

  12. Calibration of the KRISS reference ionization chamber for certification of ²²²Rn gaseous sources.

    PubMed

    Lee, J M; Lee, K B; Lee, S H; Oh, P J; Park, T S; Kim, B C; Lee, M S

    2013-11-01

    A primary measurement system for gaseous (222)Rn based on the defined solid angle counting method has recently been constructed at KRISS and the reference ionization chamber used to measure the activities of gamma-emitting single radionuclides was adopted as a secondary standard for gaseous (222)Rn. A 20 mL flame-sealed glass ampoule source from the primary measurement system was used to calibrate the ionization chamber for (222)Rn. The (222)Rn efficiency of the ionization chamber was compared with that calculated by using a photon energy-dependent efficiency curve and that measured by using a standard (226)Ra solution. From the comparisons we draw the conclusion that the reference ionization chamber for gamma-emitting radionuclides can be a suitable secondary measurement system for gaseous (222)Rn sources.

  13. Dirac solutions for quaternionic potentials

    SciTech Connect

    De Leo, Stefano Giardino, Sergio

    2014-02-15

    The Dirac equation is solved for quaternionic potentials, i V{sub 0} + j W{sub 0} (V{sub 0}∈R , W{sub 0}∈C). The study shows two different solutions. The first one contains particle and anti-particle solutions and leads to the diffusion, tunneling, and Klein energy zones. The standard solution is recovered taking the complex limit of this solution. The second solution, which does not have a complex counterpart, can be seen as a V{sub 0}-antiparticle or |W{sub 0}|-particle solution.

  14. Preparation of high purity plutonium oxide for radiochemistry instrument calibration standards and working standards

    SciTech Connect

    Wong, A.S.; Stalnaker, N.D.

    1997-04-01

    Due to the lack of suitable high level National Institute of Standards and Technology (NIST) traceable plutonium solution standards from the NIST or commercial vendors, the CST-8 Radiochemistry team at Los Alamos National Laboratory (LANL) has prepared instrument calibration standards and working standards from a well-characterized plutonium oxide. All the aliquoting steps were performed gravimetrically. When a {sup 241}Am standardized solution obtained from a commercial vendor was compared to these calibration solutions, the results agreed to within 0.04% for the total alpha activity. The aliquots of the plutonium standard solutions and dilutions were sealed in glass ampules for long term storage.

  15. Radionuclides, trace elements, and radium residence in phosphogypsum of Jordan.

    PubMed

    Zielinski, Robert A; Al-Hwaiti, Mohammad S; Budahn, James R; Ranville, James F

    2011-04-01

    Voluminous stockpiles of phosphogypsum (PG) generated during the wet process production of phosphoric acid are stored at many sites around the world and pose problems for their safe storage, disposal, or utilization. A major concern is the elevated concentration of long-lived (226)Ra (half-life = 1,600 years) inherited from the processed phosphate rock. Knowledge of the abundance and mode-of-occurrence of radium (Ra) in PG is critical for accurate prediction of Ra leachability and radon (Rn) emanation, and for prediction of radiation-exposure pathways to workers and to the public. The mean (±SD) of (226)Ra concentrations in ten samples of Jordan PG is 601 ± 98 Bq/kg, which falls near the midrange of values reported for PG samples collected worldwide. Jordan PG generally shows no analytically significant enrichment (<10%) of (226)Ra in the finer (<53 μm) grain size fraction. Phosphogypsum samples collected from two industrial sites with different sources of phosphate rock feedstock show consistent differences in concentration of (226)Ra and rare earth elements, and also consistent trends of enrichment in these elements with increasing age of PG. Water-insoluble residues from Jordan PG constitute <10% of PG mass but contain 30-65% of the (226)Ra. (226)Ra correlates closely with Ba in the water-insoluble residues. Uniformly tiny (<10 μm) grains of barite (barium sulfate) observed with scanning electron microscopy have crystal morphologies that indicate their formation during the wet process. Barite is a well-documented and efficient scavenger of Ra from solution and is also very insoluble in water and mineral acids. Radium-bearing barite in PG influences the environmental mobility of radium and the radiation-exposure pathways near PG stockpiles.

  16. Radionuclides, trace elements, and radium residence in phosphogypsum of Jordan

    USGS Publications Warehouse

    Zielinski, R.A.; Al-Hwaiti, M. S.; Budahn, J.R.; Ranville, J.F.

    2011-01-01

    Voluminous stockpiles of phosphogypsum (PG) generated during the wet process production of phosphoric acid are stored at many sites around the world and pose problems for their safe storage, disposal, or utilization. A major concern is the elevated concentration of long-lived 226Ra (half-life = 1,600 years) inherited from the processed phosphate rock. Knowledge of the abundance and mode-of-occurrence of radium (Ra) in PG is critical for accurate prediction of Ra leachability and radon (Rn) emanation, and for prediction of radiation-exposure pathways to workers and to the public. The mean (??SD) of 226Ra concentrations in ten samples of Jordan PG is 601 ?? 98 Bq/kg, which falls near the midrange of values reported for PG samples collected worldwide. Jordan PG generally shows no analytically significant enrichment (< 10%) of 226Ra in the finer (< 53 ??m) grain size fraction. Phosphogypsum samples collected from two industrial sites with different sources of phosphate rock feedstock show consistent differences in concentration of 226Ra and rare earth elements, and also consistent trends of enrichment in these elements with increasing age of PG. Water-insoluble residues from Jordan PG constitute <10% of PG mass but contain 30-65% of the 226Ra. 226Ra correlates closely with Ba in the water-insoluble residues. Uniformly tiny (< 10 ??m) grains of barite (barium sulfate) observed with scanning electron microscopy have crystal morphologies that indicate their formation during the wet process. Barite is a well-documented and efficient scavenger of Ra from solution and is also very insoluble in water and mineral acids. Radium-bearing barite in PG influences the environmental mobility of radium and the radiation-exposure pathways near PG stockpiles. ?? 2010 US Government.

  17. Characterization of the TE-NORM waste associated with oil and natural gas production in Abu Rudeis, Egypt.

    PubMed

    El Afifi, E M; Awwad, N S

    2005-01-01

    The present study was conducted to characterize the Technically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) waste generated from oil and gas production. The waste was characterized by means of dry screening solid fractionation, X-ray analysis (XRF and XRD) and gamma-ray spectrometry. Sediment of the TE-NORM waste was fractionated into ten fractions with particle sizes varying from less than 100 microm to more than 3 mm. The results showed that the TE-NORM waste contains mainly radionuclides of the 238U, 235U and 232Th series. The mean activity concentrations of 226Ra (of U-series), 228Ra (of Th-series) and 40K in the waste samples before fractionation (i.e. 3 mm) were found to amount to 68.9, 24 and 1.3 Bq/g (dry weight), respectively. After dry fractionation, the activity concentrations were widely distributed and enriched in certain fractions. This represented a 1.48 and 1.82-fold enrichment of 226Ra and 228Ra, respectively, in fraction F8 (2.0-2.5 mm) over those in bulk TE-NORM waste samples. The activity ratios of 238U/226Ra, 210Pb/226Ra, 223Ra/226Ra and 228Ra/224Ra were calculated and evaluated. Activity of the most hazardous radionuclide 226Ra was found to be higher than the exemption levels established by IAEA [International Atomic Energy Agency, 1994. International Basic Safety Standards for the Protection against Ionizing Radiation and for the Safety of Radiation Sources. GOV/2715/94, Vienna]. The radium equivalent activity (Ra-eq), radon (222Rn) emanation coefficient (EC) and absorbed dose rate (Dgammar) were estimated and these are further discussed.

  18. Determination of 210Pb, 210Po, 226Ra, 228Ra and uranium isotopes in drinking water in order to comply with the requirements of the EU ‘Drinking Water Directive.

    PubMed

    Vasile, M; Loots, H; Jacobs, K; Verheyen, L; Sneyers, L; Verrezen, F; Bruggeman, M

    2016-03-01

    The European Union published in 2013 a new Drinking Water Directive with stricter requirements for measuring natural radioactivity. In order to adhere to this, a method for sequential separation of 210Pb, 210Po, 238U and 234U in drinking water was applied using UTEVA® and Sr resins. Polonium-210, 238U and 234U were quantified using alpha-particle spectrometry and 210Pb using liquid scintillation counting. Radium-226 and 228Ra were determined using 3M Empore Radium RAD Disks, and their quantification was done using a Quantulus™ 1220 liquid scintillation counter.

  19. 238U-230Th-226Ra disequilibria in dacite and plagioclase from the 2004-2005 eruption of Mount St. Helens: Chapter 36 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Cooper, Kari M.; Donnelly, Carrie T.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    230Th)/(232Th) measured for the 1980s reference suite. However, (230Th)/(232Th) for plagioclase separates for dome samples erupted during October and November 2004 are significantly different from corresponding whole-rock values, which suggests that a large fraction (>30 percent) of crystals in each sample are foreign to the host liquid. Furthermore, plagioclase in the two 2004 samples have U-series characteristics distinct from each other and from plagioclase in dacite erupted in 1982, indicating that (1) the current eruption must include a component of crystals (and potentially associated magma) that were not sampled by the 1980-86 eruption, and (2) dacite magmas erupted only a month apart in 2004 contain different populations of crystals, indicating that this foreign component is highly heterogeneous within the 2004-5 magma reservoir.

  20. Theoretical studies of {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria in young lavas produced by mantle melting

    SciTech Connect

    Zou, H.; Zindler, A.

    2000-05-01

    This paper provides ready-to-use equations to describe variations in uranium-series (U-series) disequilibrium as a function of elemental distribution coefficients, melting porosity, melting rate, and melting time. The effects of these melting parameters on U-series disequilibria are quantitatively evaluated in both an absolute and relative sense. The importance of net elemental fractionation and ingrowth of daughter nuclides are also described and compared in terms of their relative contributions to total U-series disequilibrium. In addition, the authors compare the production of U-series disequilibrium during mantle melting to trace element fractionations produced by melting in a similar context. Trace element fractionations depend externally on the degree to which a source is melted, whereas U-series disequilibrium depends upon both the degree and rate of melting. In contrast to previous models, their approach to modeling U-series disequilibrium during dynamic melting collapses simply to a description of trace element behavior during dynamic melting when the appropriate decay terms are omitted. Their formulation shows that extremely small degrees of melting, sometimes called upon to explain observed extents of U-series disequilibrium, are not always required.

  1. Electromarking solution

    DOEpatents

    Bullock, Jonathan S.; Harper, William L.; Peck, Charles G.

    1976-06-22

    This invention is directed to an aqueous halogen-free electromarking solution which possesses the capacity for marking a broad spectrum of metals and alloys selected from different classes. The aqueous solution comprises basically the nitrate salt of an amphoteric metal, a chelating agent, and a corrosion-inhibiting agent.

  2. Training Standardization

    SciTech Connect

    Agnihotri, Newal

    2003-09-01

    The article describes the benefits of and required process and recommendations for implementing the standardization of training in the nuclear power industry in the United States and abroad. Current Information and Communication Technologies (ICT) enable training standardization in the nuclear power industry. The delivery of training through the Internet, Intranet and video over IP will facilitate this standardization and bring multiple benefits to the nuclear power industry worldwide. As the amount of available qualified and experienced professionals decreases because of retirements and fewer nuclear engineering institutions, standardized training will help increase the number of available professionals in the industry. Technology will make it possible to use the experience of retired professionals who may be interested in working part-time from a remote location. Well-planned standardized training will prevent a fragmented approach among utilities, and it will save the industry considerable resources in the long run. It will also ensure cost-effective and safe nuclear power plant operation.

  3. Solution preparation

    SciTech Connect

    Seitz, M.G.

    1982-01-01

    Reviewed in this statement are methods of preparing solutions to be used in laboratory experiments to examine technical issues related to the safe disposal of nuclear waste from power generation. Each approach currently used to prepare solutions has advantages and any one approach may be preferred over the others in particular situations, depending upon the goals of the experimental program. These advantages are highlighted herein for three approaches to solution preparation that are currently used most in studies of nuclear waste disposal. Discussion of the disadvantages of each approach is presented to help a user select a preparation method for his particular studies. Also presented in this statement are general observations regarding solution preparation. These observations are used as examples of the types of concerns that need to be addressed regarding solution preparation. As shown by these examples, prior to experimentation or chemical analyses, laboratory techniques based on scientific knowledge of solutions can be applied to solutions, often resulting in great improvement in the usefulness of results.

  4. Infinite dilution partial molar properties of aqueous solutions of nonelectrolytes. 1. Equations for partial molar volumes at infinite dilution and standard thermodynamic functions of hydration of volatile nonelectrolytes over wide ranges of conditions

    SciTech Connect

    Plyasunov, A.V.; O'Connell, J.P.; Wood, R.H.

    2000-02-01

    A semitheoretical expression for partial molar volumes at infinite dilution of aqueous nonelectrolyte solutes has been developed employing the collection of properties from fluctuation solution theory for use over wide ranges of temperature and pressure. The form of the solution expression was suggested by a comparison of solute/solvent and solvent/solvent direct correlations function integrals (DCFI). The selection of solvent density and compressibility as model variables provides a correct description in the critical region while second virial coefficients have been used to give a rigorous expression in the low density region. The formulation has been integrated to obtain analytic expressions for thermodynamic properties of hydration at supercritical temperatures. The equation is limited to solutes for which B{sub 12} (the second cross virial coefficient between water and a solute molecule) is known or can be estimated. Regression of the three remaining parameters gives good correlations of the available experimental data. A strategy for estimating these parameters allows prediction from readily available data.

  5. EOS standards

    SciTech Connect

    Greeff, Carl W

    2011-01-12

    An approach to creating accurate EOS for pressure standards is described. Applications to Cu, Au, and Ta are shown. Extension of the method to high compressions using DFT is illustrated. Comparisons with modern functionals show promise.

  6. Networking standards

    NASA Technical Reports Server (NTRS)

    Davies, Mark

    1991-01-01

    The enterprise network is currently a multivendor environment consisting of many defacto and proprietary standards. During the 1990s, these networks will evolve towards networks which are based on international standards in both Local Area Network (LAN) and Wide Area Network (WAN) space. Also, you can expect to see the higher level functions and applications begin the same transition. Additional information is given in viewgraph form.

  7. (Terminology standardization)

    SciTech Connect

    Strehlow, R.A.

    1990-10-19

    Terminological requirements in information management was but one of the principal themes of the 2nd Congress on Terminology and Knowledge Engineering. The traveler represented the American Society for Testing and Materials' Committee on Terminology, of which he is the Chair. The traveler's invited workshop emphasized terminology standardization requirements in databases of material properties as well as practical terminology standardizing methods. The congress included six workshops in addition to approximately 82 lectures and papers from terminologists, artificial intelligence practitioners, and subject specialists from 18 countries. There were approximately 292 registrants from 33 countries who participated in the congress. The congress topics were broad. Examples were the increasing use of International Standards Organization (ISO) Standards in legislated systems such as the USSR Automated Data Bank of Standardized Terminology, the enhanced Physics Training Program based on terminology standardization in Physics in the Chinese province of Inner Mongolia, and the technical concept dictionary being developed at the Japan Electronic Dictionary Research Institute, which is considered to be the key to advanced artificial intelligence applications. The more usual roles of terminology work in the areas of machine translation. indexing protocols, knowledge theory, and data transfer in several subject specialties were also addressed, along with numerous special language terminology areas.

  8. "There's Nothing Standard about Standards": Exploring Tensions between Two Standards Documents in Higher Education

    ERIC Educational Resources Information Center

    Bourke, Terri; Carter, Jennifer

    2016-01-01

    Quality in education at the tertiary level is constantly questioned, and increasingly "professional standards" are offered as the solution to the perceived decline in quality. Foucauldian archaeological analysis of teacher graduate and geography graduate standards in Australia is conducted, revealing tensions between the different…

  9. Nanoparticle standards

    SciTech Connect

    Havrilla, George Joseph

    2016-12-08

    We will purchase a COTS materials printer and adapt it for solution printing of known elemental concentration solutions. A methodology will be developed to create deposits of known mass in known locations on selected substrates. The deposits will be characterized for deposited mass, physical morphology, thickness and uniformity. Once an acceptable methodology has been developed and validated, we will create round robin samples to be characterized by LGSIMS instruments at LANL, PNNL and NIST. We will demonstrate the feasibility of depositing nanoparticles in known masses with the goal of creating separated nanoparticles in known locations.

  10. Measurements of radioactivity in Jamaican building materials and gamma dose equivalents in a prototype red mud house

    SciTech Connect

    Pinnock, W.R. )

    1991-11-01

    Concentrations of 226Ra, 232Th, and 40K measured in bauxite waste, local building materials, and soils are presented and used in model equations to estimate the effective gamma dose-equivalent increments over background in the center of a standard-sized room in a prototype house. Calculated and measured values compare reasonably well.

  11. Behavior and environmental impacts of radionuclides during the hydrometallurgy of calcareous and argillaceous rocks, southwestern Sinai, Egypt.

    PubMed

    El Aassy, Ibrahim E; Nada, Afaf A; El Galy, Mohamed M; El Feky, Mohamed G; Abd El Maksoud, Thanaa M; Talaat, Shadia M; Ibrahim, Eman M

    2012-06-01

    The hydrometallurgy of radionuclides means getting the radioelements from the rocks into solution by leaching, getting the radionuclides from the solution by extraction process, and then precipitation of the desired elements to obtain concentrate. The follow-up of the radionuclides during these processes is the main target of this work to identify the identity of the original samples, pregnant solutions (leachates), residuals and the concentrate. Six samples were chosen to achieve this work. The leaching process was carried out under the conditions; 20-30% acid (H(2)SO(4)) concentration, 1:3 solid/liquid ratios, 60 min stirring time at room temperature. The activity concentrations of (238)U, (235)U, (234)U, (226)Ra, (214)Pb, (214)Bi, (232)Th and (40)K were measured in the original samples, residuals and U-concentrate (Bq/kg), and leachates (Bq/ℓ). The results indicate that, the radionuclides before (226)Ra in the (238)U decay series are more leachable (released) than those from (226)Ra to (214)Bi in the order; (234)U>(238)U=(235)U > (226)Ra>(214)Pb>(214)Bi. (232)Th and (40)K are immobile under the present conditions. The radiological hazards of natural radioactivity in the original samples, leachates, residuals and U-concentrate were calculated and compared with the internationally recommended values and were found to be much higher than the world average values. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Rapid determination of the equivalence volume in potentiometric acid-base titrations to a preset pH-II Standardizing a solution of a strong base, graphic location of equivalence volume, determination of stability constants of acids and titration of a mixture of two weak acids.

    PubMed

    Ivaska, A

    1974-06-01

    A newly proposed method of titrating weak acids with strong bases is applied to standardize a solution of a strong base, to graphic determination of equivalence volume of acetic acid with an error of 0.2%, to calculate the stability constants of hydroxylammonium ion, boric acid and hydrogen ascorbate ion and to analyse a mixture of acetic acid and ammonium ion with an error of 0.2-0.7%.

  13. Spaceflight Human System Standards

    NASA Technical Reports Server (NTRS)

    Holubec, Keith; Tillman, Barry; Connolly, Jan

    2009-01-01

    NASA created a new approach for human system integration and human performance standards. NASA created two documents a standard and a reference handbook. The standard is titled NASA Space Flight Human-System Standard (SFHSS) and consists of two-volumes: Volume 1- Crew Health This volume covers standards needed to support astronaut health (medical care, nutrition, sleep, exercise, etc.) Volume 2 Human Factors, Habitability and Environmental Health This volume covers the standards for system design that will maintain astronaut performance (ie., environmental factors, design of facilities, layout of workstations, and lighting requirements). It includes classic human factors requirements. The new standards document is written in terms so that it is applicable to a broad range of present and future NASA systems. The document states that all new programs prepare system-specific requirements that will meet the general standards. For example, the new standard does not specify a design should accommodate specific percentiles of a defined population. Rather, NASA-STD-3001, Volume 2 states that all programs shall prepare program-specific requirements that define the user population and their size ranges. The design shall then accommodate the full size range of those users. The companion reference handbook, Human Integration Design Handbook (HIDH), was developed to capture the design consideration information from NASA-STD-3000, and adds spaceflight lessons learned, gaps in knowledge, example solutions, and suggests research to further mature specific disciplines. The HIDH serves two major purposes: HIDH is the reference document for writing human factors requirements for specific systems. HIDH contains design guidance information that helps insure that designers create systems which safely and effectively accommodate the capabilities and limitations of space flight crews.

  14. Spaceflight Human System Standards

    NASA Technical Reports Server (NTRS)

    Holubec, Keith; Tillman, Barry; Connolly, Jan

    2009-01-01

    NASA created a new approach for human system integration and human performance standards. NASA created two documents a standard and a reference handbook. The standard is titled NASA Space Flight Human-System Standard (SFHSS) and consists of two-volumes: Volume 1- Crew Health This volume covers standards needed to support astronaut health (medical care, nutrition, sleep, exercise, etc.) Volume 2 Human Factors, Habitability and Environmental Health This volume covers the standards for system design that will maintain astronaut performance (ie., environmental factors, design of facilities, layout of workstations, and lighting requirements). It includes classic human factors requirements. The new standards document is written in terms so that it is applicable to a broad range of present and future NASA systems. The document states that all new programs prepare system-specific requirements that will meet the general standards. For example, the new standard does not specify a design should accommodate specific percentiles of a defined population. Rather, NASA-STD-3001, Volume 2 states that all programs shall prepare program-specific requirements that define the user population and their size ranges. The design shall then accommodate the full size range of those users. The companion reference handbook, Human Integration Design Handbook (HIDH), was developed to capture the design consideration information from NASA-STD-3000, and adds spaceflight lessons learned, gaps in knowledge, example solutions, and suggests research to further mature specific disciplines. The HIDH serves two major purposes: HIDH is the reference document for writing human factors requirements for specific systems. HIDH contains design guidance information that helps insure that designers create systems which safely and effectively accommodate the capabilities and limitations of space flight crews.

  15. Software Solutions for ICME

    NASA Astrophysics Data System (ADS)

    Schmitz, G. J.; Engstrom, A.; Bernhardt, R.; Prahl, U.; Adam, L.; Seyfarth, J.; Apel, M.; de Saracibar, C. Agelet; Korzhavyi, P.; Ågren, J.; Patzak, B.

    2016-01-01

    The Integrated Computational Materials Engineering expert group (ICMEg), a coordination activity of the European Commission, aims at developing a global and open standard for information exchange between the heterogeneous varieties of numerous simulation tools. The ICMEg consortium coordinates respective developments by a strategy of networking stakeholders in the first International Workshop on Software Solutions for ICME, compiling identified and relevant software tools into the Handbook of Software Solutions for ICME, discussing strategies for interoperability between different software tools during a second (planned) international workshop, and eventually proposing a scheme for standardized information exchange in a future book or document. The present article summarizes these respective actions to provide the ICME community with some additional insights and resources from which to help move this field forward.

  16. Solid Solutions

    NASA Astrophysics Data System (ADS)

    Lee, Go-Eun; Kim, Il-Ho; Lim, Young Soo; Seo, Won-Seon; Choi, Byeong-Jun; Hwang, Chang-Won

    2014-06-01

    Since Bi2Te3 and Bi2Se3 have the same crystal structure, they form a homogeneous solid solution. Therefore, the thermal conductivity of the solid solution can be reduced by phonon scattering. The thermoelectric figure of merit can be improved by controlling the carrier concentration through doping. In this study, Bi2Te2.85Se0.15:D m (D: dopants such as I, Cu, Ag, Ni, Zn) solid solutions were prepared by encapsulated melting and hot pressing. All specimens exhibited n-type conduction in the measured temperature range (323 K to 523 K), and their electrical conductivities decreased slightly with increasing temperature. The undoped solid solution showed a carrier concentration of 7.37 × 1019 cm-3, power factor of 2.1 mW m-1 K-1, and figure of merit of 0.56 at 323 K. The figure of merit ( ZT) was improved due to the increased power factor by I, Cu, and Ag dopings, and maximum ZT values were obtained as 0.76 at 323 K for Bi2Te2.85Se0.15:Cu0.01 and 0.90 at 423 K for Bi2Te2.85Se0.15:I0.005. However, the thermoelectric properties of Ni- and Zn-doped solid solutions were not enhanced.

  17. A fluorimeter for solutions

    USGS Publications Warehouse

    Fletcher, Mary H.; Warner, E. Ray

    1953-01-01

    description of and complete drawings for the construction of a fluorimeter for the measurement of fluorescence of solutions are given. The instrument is sturdy and versatile. It may be used with various phototubes and measuring devices. It is constructed so that phototubes and filters may be changed readily. Sensitivity is controlled easily over a wide range by limiting the size of either the ultraviolet or fluorescent light beam with standard apertures.

  18. Polyelectrolyte Solutions

    NASA Astrophysics Data System (ADS)

    Colby, Ralph H.

    2008-03-01

    Pierre-Gilles de Gennes once described polyelectrolytes as the ``least understood form of condensed matter''. In this talk, I will describe the state of the polyelectrolyte field before and after de Gennes' seminal contributions published 1976-1980. De Gennes clearly explained why electrostatic interactions only stretch the polyelectrolyte chains on intermediate scales in semidilute solution (between the electrostatic blob size and the correlation length) and why the scattering function has a peak corresponding to the correlation length (the distance to the next chain). Despite many other ideas being suggested since then, the simple de Gennes scaling picture of polyelectrolyte conformation in solution has stood the test of time. How that model is used today, including consequences for dynamics in polyelectrolyte solutions, and what questions remain, will clarify the importance of de Gennes' ideas.

  19. 40 CFR 428.35 - Standards of performance for new sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Solution Crumb Rubber Subcategory § 428.35 Standards of performance for new sources. The following standards...

  20. 40 CFR 428.35 - Standards of performance for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Solution Crumb Rubber Subcategory § 428.35 Standards of performance for new sources. The following standards...

  1. 40 CFR 428.35 - Standards of performance for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Solution Crumb Rubber Subcategory § 428.35 Standards of performance for new sources. The following standards...

  2. Radium release mechanisms during hydraulic fracturing of Marcellus Shale

    NASA Astrophysics Data System (ADS)

    Sharma, M.; Landis, J. D.; Renock, D. J.

    2016-12-01

    Wastewater co-produced with methane from Devonian Marcellus Shale is hypersaline and enriched in Ra. Recent studies find that water injected during hydraulic fracturing can leach out significant quantities of Na, Ca, Ba and Sr from solid phases in the shale over just hours to days. Here, we show with water-rock leaching experiments that the measured 226Ra/228Ra ratios of Marcellus wastewater could also derive from rapid leaching of mineral and organic phases of the shale. Radium isotopes 226Ra (t1/2 = 1600 a) and 228Ra (t1/2 = 5.8 a) are produced through radioactive decay of 238U (t1/2 = 4.5 Ga) and 232Th (t1/2 = 14 Ga), respectively. In the absence of processes that fractionate U, Th and Ra from one another, the decay rates of each parent-daughter pair become identical over 5 half-lives of the daughter radionuclide reaching a condition of secular equilibrium. Water-rock interaction may induce pronounced deviations from secular equilibrium in the water phase, however. Such is the case during hydraulic fracturing, where Ra is soluble and mobile, and is orphaned from insoluble U and Th parents. Once 226Ra and 228Ra are mobilized no fractionation between these isotopes is expected during their transport to the surface. Thus the 226Ra/228Ra ratio in wastewater provides a fingerprint of Ra source(s). Leaching Marcellus Shale with pure water under anoxic conditions releases mainly 228Ra from clays; extraction of 228Ra from radiation damaged sites is likely the dominant contributing mechanism. Using a novel isotope dilution technique we find that 90% of the Ra released in pure water partitions back onto rock (possibly clays). In comparison, leaching with high ionic strength solutions induces the release of 226Ra from mainly organics; the breakdown of organic matter in these solutions may be the driving mechanism controlling 226Ra release in solution. Radium released by high ionic strength solutions strongly partitions into water and results in the development of leachates

  3. Pesticide Standards

    ERIC Educational Resources Information Center

    Shea, Kevin P.

    1976-01-01

    The Environmental Protection Agency chose the American Society of Testing and Materials to develop standardized guidelines for pesticide registration. Since the numbers and uses of pesticides is so wide, establishing ecological and public health guidelines may be difficult. Strong industry and government representation might also hamper the…

  4. Pesticide Standards

    ERIC Educational Resources Information Center

    Shea, Kevin P.

    1976-01-01

    The Environmental Protection Agency chose the American Society of Testing and Materials to develop standardized guidelines for pesticide registration. Since the numbers and uses of pesticides is so wide, establishing ecological and public health guidelines may be difficult. Strong industry and government representation might also hamper the…

  5. Polymer solutions

    DOEpatents

    Krawczyk, Gerhard Erich; Miller, Kevin Michael

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  6. -Saturated Solutions

    NASA Astrophysics Data System (ADS)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2014-11-01

    This paper presents an electrochemical study on the corrosion behavior of API-X100 steel, heat-treated to have microstructures similar to those of the heat-affected zones (HAZs) of pipeline welding, in bicarbonate-CO2 saturated solutions. The corrosion reactions, onto the surface and through the passive films, are simulated by cyclic voltammetry. The interrelation between bicarbonate concentration and CO2 hydration is analyzed during the filming process at the open-circuit potentials. In dilute bicarbonate solutions, H2CO3 drives more dominantly the cathodic reduction and the passive films form slowly. In the concentrated solutions, bicarbonate catalyzes both the anodic and cathodic reactions, only initially, after which it drives a fast-forming thick passivation that inhibits the underlying dissolution and impedes the cathodic reduction. The significance of the substrate is as critical as that of passivation in controlling the course of the corrosion reactions in the dilute solutions. For fast-cooled (heat treatment) HAZs, its metallurgical significance becomes more comparable to that of slower-cooled HAZs as the bicarbonate concentration is higher.

  7. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  8. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  9. Interface standardization

    NASA Technical Reports Server (NTRS)

    Spencer, R.; Wong, V.

    1983-01-01

    Central-station applications create a large and attractive market for photovoltaics in the near future. However, some significant barriers lie between the industry of today and realization of that market. Manufacturing capacity and price are two principal impediments. The Utilities, which are the future system owners, are gaining experience with central-station PV power through the Sacramento Municipal Utility District, Hesperia and similar small central-station installations. SMUD has recognized that competition must be maintained to help reduce prices. So little standardization exists that the cost is driven upward to redefine mechanical and electrical interfaces for each vendor. New structues are required for each vendor and nonoptimum field geometries result from attempts to include more than one vendor in an array field. Standards at some hardware level are required.

  10. Interface standardization

    NASA Technical Reports Server (NTRS)

    Spencer, R.; Wong, V.

    1983-01-01

    Central-station applications create a large and attractive market for photovoltaics in the near future. However, some significant barriers lie between the industry of today and realization of that market. Manufacturing capacity and price are two principal impediments. The Utilities, which are the future system owners, are gaining experience with central-station PV power through the Sacramento Municipal Utility District, Hesperia and similar small central-station installations. SMUD has recognized that competition must be maintained to help reduce prices. So little standardization exists that the cost is driven upward to redefine mechanical and electrical interfaces for each vendor. New structues are required for each vendor and nonoptimum field geometries result from attempts to include more than one vendor in an array field. Standards at some hardware level are required.

  11. Cereal based oral rehydration solutions.

    PubMed

    Kenya, P R; Odongo, H W; Oundo, G; Waswa, K; Muttunga, J; Molla, A M; Nath, S K; Molla, A; Greenough, W B; Juma, R

    1989-07-01

    A total of 257 boys (age range 4-55 months), who had acute diarrhoea with moderate to severe dehydration, were randomly assigned to treatment with either the World Health Organisation/United Nations Childrens Fund (WHO/Unicef) recommended oral rehydration solution or cereal based oral rehydration solution made either of maize, millet, sorghum, or rice. After the initial rehydration was achieved patients were offered traditional weaning foods. Treatment with oral rehydration solution continued until diarrhoea stopped. Accurate intake and output was maintained throughout the study period. Efficacy of the treatment was compared between the different treatment groups in terms of intake of the solution, stool output, duration of diarrhoea after admission, and weight gain after 24, 48, and 72 hours, and after resolution of diarrhoea. Results suggest that all the cereal based solutions were as effective as glucose based standard oral rehydration solution in the treatment of diarrhoea.

  12. Parenteral drug products containing aluminum as an ingredient or a contaminant: Response to Food and Drug Administration notice of intent and request for information. ASCN/A. S. P. E. N. Working Group on Standards for Aluminum Content of Parenteral Nutrition Solutions

    SciTech Connect

    Not Available

    1991-03-01

    Aluminum remains a significant contaminant of total parenteral nutrition (TPN) solutions and may be elevated in bone, urine, and plasma of infants receiving TPN. Aluminum accumulation in tissues of uremic patients and adult TPN patients has been associated with low-turnover bone disease. Furthermore, aluminum has also been linked with encephalopathy and anemia in uremic patients and with hepatic cholestasis in experimental animals. Because of the toxic effects of aluminum, the Food and Drug Administration (FDA) recently published a notice of intent to set an upper limit of 25 micrograms/L for aluminum in large-volume parenterals and to require manufacturers of small-volume parenterals, such as calcium and phosphate salts, to measure aluminum content and note this content on the package label. The ASCN/A.S.P.E.N. Working Group on Standards for Aluminum Content of Parenteral Nutrition Solutions supports these intentions and further urges the FDA to require that cumulative aluminum intake in terms of safe, unsafe, and toxic quantities of aluminum per kilogram be made known to physicians and pharmacists preparing the TPN solutions, to ensure that manufacturers use appropriate control procedures in aluminum measurements, and to employ a standard unit of aluminum measurement.

  13. [Standard rhinoplasty].

    PubMed

    Bardot, J; Jallut, Y; Nguyen, P-S

    2014-12-01

    Most patients who consult a surgeon for rhinoplasty do not want a radical change in their nose. They seek a reduction in the volume of the nasal pyramid and correction of a precise element that they judge to be ungainly--most often an osteocartilaginous hump. The procedure that we qualify as "standard" will eliminate the osteocartilaginous hump, decrease the dimensions of the septum and reduce the size of the alar crus of the alar cartilage. Although the required technical maneuvers are simple, their sequence must be coherent with a few basic rules that are simple but rarely explained in order to avoid defects linked to excessive, or on the contrary, insufficient corrections.

  14. Standardizing Immunohistochemistry

    PubMed Central

    Sompuram, Seshi R.; Vani, Kodela; Tracey, Brian; Kamstock, Debra A.

    2015-01-01

    A new standardized immunohistochemistry (IHC) control for breast cancer testing comprises formalin-fixed human epidermal growth factor receptor 2, estrogen receptor, or progesterone receptor peptide antigens covalently attached to 8-µm glass beads. The antigen-coated beads are suspended in a liquid matrix that hardens upon pipetting onto a glass microscope slide. The antigen-coated beads remain in place through deparaffinization, antigen retrieval, and immunostaining. The intensity of the beads’ stain provides feedback regarding the efficacy of both antigen retrieval and immunostaining. As a first report, we tested the sensitivity and specificity of the new IHC controls (“IHControls”). To evaluate sensitivity, various staining problems were simulated. IHControls detected primary and secondary reagent degradation similarly to tissue controls. This first group of IHControls behaved similarly to tissue controls expressing high concentrations of the antigen. The IHControls were also able to detect aberrations in antigen retrieval, as simulated by sub-optimal times or temperatures. Specificity testing revealed that each antigen-coated bead was specific for its cognate IHC test antibody. The data support the conclusion that, like tissue controls, IHControls are capable of verifying the analytic components of an immunohistochemical stain. Unlike tissue controls, IHControls are prepared in large bulk lots, fostering day-to-day reproducibility that can be standardized across laboratories. PMID:25940339

  15. Radioactivity levels and heavy metals in the urban soil of Central Serbia.

    PubMed

    Milenkovic, B; Stajic, J M; Gulan, Lj; Zeremski, T; Nikezic, D

    2015-11-01

    Radioactivity concentrations and heavy metal content were measured in soil samples collected from the area of Kragujevac, one of the largest cities in Serbia. The specific activities of (226)Ra, (232)Th, (40)K and (137)Cs in 30 samples were measured by gamma spectrometry using an HPGe semiconductor detector. The average values ± standard deviations were 33.5 ± 8.2, 50.3 ± 10.6, 425.8 ± 75.7 and 40.2 ± 26.3 Bq kg(-1), respectively. The activity concentrations of (226)Ra, (232)Th and (137)Cs have shown normal distribution. The annual effective doses, radium equivalent activities, external hazard indexes and excess lifetime cancer risk were also estimated. A RAD7 device was used for measuring radon exhalation rates from several samples with highest content of (226)Ra. The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were measured, as well as their EDTA extractable concentrations. Wide ranges of values were obtained, especially for Cr, Mn, Ni, Pb and Zn. The absence of normal distribution indicates anthropogenic origin of Cr, Ni, Pb and Zn. Correlations between radionuclide activities, heavy metal contents and physicochemical properties of analysed soil were determined by Spearman correlation coefficient. Strong positive correlation between (226)Ra and (232)Th was found.

  16. Sustainable agricultural use of natural water sources containing elevated radium activity.

    PubMed

    Tripler, Effi; Haquin, Gustavo; Koch, Jean; Yehuda, Zehava; Shani, Uri

    2014-06-01

    Relatively elevated concentrations of naturally occurring radium isotopes ((226)Ra, (228)Ra and (224)Ra) are found in two main aquifers in the arid southern part of Israel, in activity concentrations frequently exceeding the limits set in the drinking water quality regulations. We aimed to explore the environmental implications of using water containing Ra for irrigation. Several crops (cucumbers, melons, radish, lettuce, alfalfa and wheat), grown in weighing lysimeters were irrigated at 3 levels of (226)Ra activity concentration: Low Radium Water (LRW)<0.04 Bq L(-1); High Radium Water (HRW) at 1.8 Bq L(-1) and (3) Radium Enriched Water (REW) at 50 times the concentration in HRW. The HYDRUS 1-D software package was used to simulate the long-term (226)Ra distribution in a soil irrigated with HRW for 15 years. Radium uptake by plants was found to be controlled by its activity in the irrigation water and in the soil solution, the physical properties of the soil and the potential evapotranspiration. The (226)Ra apeared to accumulate mainly in the leaves of crops following the evapotranspiration current, while its accumulation in the edible parts (fruits and roots) was minimal. The simulation of 15 years of crop irrigation by HYDERUS 1-D, showed a low Ra activity concentration in the soil solution of the root zone and a limited downward mobility. It was therefore concluded that the crops investigated in this study can be irrigated with the natural occurring activity concentration of (226)Ra of 0.6-1.6 Bq L(-1). This should be accompanied by a continuous monitoring of radium in the edible parts of the crops.

  17. The beryllium "double standard" standard.

    PubMed

    Egilman, David S; Bagley, Sarah; Biklen, Molly; Golub, Alison Stern; Bohme, Susanna Rankin

    2003-01-01

    Brush Wellman, the world's leading producer and supplier of beryllium products, has systematically hidden cases of beryllium disease that occurred below the threshold limit value (TLV) and lied about the efficacy of the TLV in published papers, lectures, reports to government agencies, and instructional materials prepared for customers and workers. Hypocritically, Brush Wellman instituted a zero exposure standard for corporate executives while workers and customers were told the 2 microgram standard was "safe." Brush intentionally used its workers as "canaries for the plant," and referred to them as such. Internal documents and corporate depositions indicate that these actions were intentional and that the motive was money. Despite knowledge of the inadequacy of the TLV, Brush has successfully used it as a defense against lawsuits brought by injured workers and as a sales device to provide reassurance to customers. Brush's policy has reaped an untold number of victims and resulted in mass distribution of beryllium in consumer products. Such corporate malfeasance is perpetuated by the current market system, which is controlled by an organized oligopoly that creates an incentive for the neglect of worker health and safety in favor of externalizing costs to victimized workers, their families, and society at large.

  18. Exact solutions and singularities in string theory

    SciTech Connect

    Horowitz, G.T. ); Tseytlin, A.A. )

    1994-10-15

    We construct two new classes of exact solutions to string theory which are not of the standard plane wave of gauged WZW type. Many of these solutions have curvature singularities. The first class includes the fundamental string solution, for which the string coupling vanishes near the singularity. This suggests that the singularity may not be removed by quantum corrections. The second class consists of hybrids of plane wave and gauged WZW solutions. We discuss a four-dimensional example in detail.

  19. National Green Building Standard Analysis

    SciTech Connect

    NAHB Research Center, Upper Marlboro, Maryland

    2012-07-01

    DOE's Building America Program is a research and development program to improve the energy performance of new and existing homes. The ultimate goal of the Building America Program is to achieve examples of cost-effective, energy efficient solutions for all U.S. climate zones. Periodic maintenance of an ANSI standard by review of the entire document and action to revise or reaffirm it on a schedule not to exceed five years is required by ANSI. In compliance, a consensus group has once again been formed and the National Green Building Standard is currently being reviewed to comply with the periodic maintenance requirement of an ANSI standard.

  20. Standard atmosphere

    NASA Technical Reports Server (NTRS)

    Gregg, Willis Ray

    1923-01-01

    This report was prepared at the request of the National Advisory Committee for Aeronautics and discusses the need of a standard set of values of pressure, temperature and density at various altitudes and points out the desirability of adopting such values as are most in accord with actual average conditions, in order that corrections in individual cases may be as small as possible. To meet this need, so far as the united states is concerned, all free-air observations obtained by means of kites and balloons at several stations in this country near latitude 40 degrees N., have been used, and average values of pressure, temperature, and density, based upon those observations, have been determined for summer, winter, and the year, and for all altitudes up to 20,000 meters (65,000 feet). These values are presented in tables and graphs in both metric and english units; and in the tables of densities there are also included values of density for other parts of the world, more particularly for Europe. A comparison with these values shows that, except in the lowest levels, the agreement is very satisfactory.

  1. Mycobactericidal activity of glutaraldehyde solutions.

    PubMed Central

    Collins, F M; Montalbine, V

    1976-01-01

    Aqueous solutions of alkaline glutaraldehyde (buffered at pH 8.5) inactivated a standard suspension of Mycobacterium tuberculosis H37Rv faster than the corresponding acid (pH 3.7 preparation. Quantitative differences in the rate of inactivation of eight other species of Mycobacterium were determined using a 1% solution of alkaline glutaraldehyde and inactivation of residual glutaraldehyde with 1% sodium bisulfite solution. Variations in the rate of kill were observed between the various mycobacterial species tested, but such differences were probably not sufficiently large to be of practical importance. A 2% alkaline glutaraldehyde solution inactivated 10(5) viable M. tuberculosis cells present on the surface of porcelain penicylinders within 5 min at 18 degrees C. This rate of inactivation was faster than in the acidic solution. PMID:11227

  2. US Geological Survey research on the environmental fate of uranium mining and milling wastes

    USGS Publications Warehouse

    Landa, E.R.; Gray, J.R.

    1995-01-01

    Studies by the US Geological Survey (USGS) of uranium mill tailings (UMT) have focused on characterizing the forms in which radionuclides are retained and identifying factors influencing the release of radionuclides to air and water. Selective extraction studies and studies of radionuclide sorption by and leaching from components of UMT showed alkaline earth sulfate and hydrous ferric oxides to be important hosts of radium-226 (226Ra) in UMT. Extrapolating from studies of barite dissolution in anerobic lake sediments, the leaching of 226Ra from UMT by sulfate-reducing bacteria was investigated; a marked increase in 226Ra release to aqueous solution as compared to sterile controls was demonstrated. A similar action of iron(III)-reducing bacteria was later shown. Ion exchangers such as clay minerals can also promote the dissolution of host-phase minerals and thereby influence the fate of radionuclides such as 226Ra. Radon release studies examined particle size and ore composition as variables. Aggregation of UMT particles was shown to mask the higher emanating fraction of finer particles. Studies of various ores and ore components showed that UMT cannot be assumed to have the same radon-release characteristics as their precursor ores, nor can 226Ra retained by various substrates be assumed to emanate the same fraction of radon. Over the last decade, USGS research directed at offsite mobility of radionuclides from uranium mining and milling processes has focused on six areas: the Midnite Mine in Washington; Ralston Creek and Reservoir, Colorado; sites near Canon City, Colorado; the Monument Valley District of Arizona and Utah; the Cameron District of Arizona; and the Puerco River basin of Arizona and New Mexico.

  3. Radium and radium-daughter nuclides in carbonates: a brief overview of strategies for determining chronologies.

    PubMed

    Schmidt, Sabine; Cochran, J Kirk

    2010-07-01

    Radium isotopes have been used extensively to trace the movement of groundwater as well as oceanic water masses, but these radionuclides (and their daughters) are also useful chronometers for the determination of the time scales of other Earth and environmental processes. The purpose of this overview is to present the application of Ra and Ra daughters in the dating of carbonates. We show that the choice of dating method (decay of excess radionuclide or ingrowth of daughter) depends strongly on the parent/daughter activity ratios in the water in which the carbonate was precipitated. Thus freshly precipitated carbonates uniformly show excesses of 226Ra relative to its parent 230Th, and 226Ra decay can provide ages of carbonates over Holocene time scales. In contrast, carbonates are precipitated in waters of greatly varying 210Pb/226Ra. Corals, deep-sea hydrothermal vent clams and the shelled cephalopod Nautilus live in waters with significant dissolved 210Pb and all show excesses of 210Pb in their carbonate. Bivalve molluscs from nearshore and coastal waters, and carbonates deposited from groundwater environments (e.g. travertines) in which 210Pb is efficiently scavenged from solution, show deficiencies of 210Pb relative to 226Ra. In contrast, fish otoliths strongly discriminate against 210Pb regardless of the environment in which the fish lives. Deficiencies of 228Th relative to 228Ra are common in all carbonates. Useful time ranges for the 210Pb/226Ra and 228Th/228Ra chronometers are approximately 100 y and approximately 10 y, respectively. 2009 Elsevier Ltd. All rights reserved.

  4. US Geological Survey research on the environmental fate of uranium mining and milling wastes

    NASA Astrophysics Data System (ADS)

    Landa, E. R.; Gray, J. R.

    1995-07-01

    Studies by the US Geological Survey (USGS) of uranium mill tailings (UMT) have focused on characterizing the forms in which radionuclides are retained and identifying factors influencing the release of radionuclides to air and water. Selective extraction studies and studies of radionuclide sorption by and leaching from components of UMT showed alkaline earth sulfate and hydrous ferric oxides to be important hosts of radium-226 (226Ra) in UMT. Extrapolating from studies of barite dissolution in anerobic lake sediments, the leaching of226Ra from UMT by sulfate-reducing bacteria was investigated; a marked increase in226Ra release to aqueous solution as compared to sterile controls was demonstrated. A similar action of iron(III)-reducing bacteria was later shown. Ion exchangers such as clay minerals can also promote the dissolution of host-phase minerals and thereby influence the fate of radionuclides such as226Ra. Radon release studies examined particle size and ore composition as variables. Aggregation of UMT particles was shown to mask the higher emanating fraction of finer particles. Studies of various ores and ore components showed that UMT cannot be assumed to have the same radon-release characteristics as their precursor ores, nor can226Ra retained by various substrates be assumed to emanate the same fraction of radon. Over the last decade, USGS research directed at offsite mobility of radionuclides from uranium mining and milling processes has focused on six areas: the Midnite Mine in Washington; Ralston Creek and Reservoir, Colorado; sites near Canon City, Colorado; the Monument Valley District of Arizona and Utah; the Cameron District of Arizona; and the Puerco River basin of Arizona and New Mexico.

  5. Journal standards.

    PubMed

    Jackson, R

    2003-08-01

    Despite its many imperfections, the peer review process is a firmly established quality control system for scientific literature. It gives readers some assurance that the work and views that are reported meet standards that are acceptable to a journal. Maureen Revington's editorial in a recent issue of the Australian Veterinary Journal (Revington2002) gives a good concise warts and all overview of the process and is well worth reading. I have some concerns about several articles in the December 2002 issue of the New Zealand Veterinary Journal (Volume 50, Number 6), devoted to the health and welfare of farmed deer, that relate to extensive citing of non-peer reviewed papers. I can understand the need for information to flow from researchers to the wider community but that need is already satisfied by publications such as the proceedings of the Deer Branch of the New Zealand Veterinary Association and Proceedings of the New Zealand Society of Animal Production. Non-peer reviewed papers have been cited in the Journal in the past but never to the extent displayed in this particular issue. It degrades the peer-review process and creates an added burden for reviewers who are forced to grapple with the uncertainties of the science in non-peer reviewed citations. One of my fears is that this process allows science from non peer reviewed articles to be legitimised by its inclusion in a peer reviewed journal and perhaps go on to be accepted as dogma. This is a real danger given the difficulties associated with tracing back to original citations and the increasing volume of scientific literature. It also affords opportunities for agencies to pick up questionable and doubtful science and tout it as support for their products or particular points of view. If deer researchers choose to publish most of their work in proceedings then so be it. However this approach, which seems to becoming increasingly prevalent in the deer sector, is questionable from an established science point

  6. Alloy solution hardening with solute pairs

    DOEpatents

    Mitchell, John W.

    1976-08-24

    Solution hardened alloys are formed by using at least two solutes which form associated solute pairs in the solvent metal lattice. Copper containing equal atomic percentages of aluminum and palladium is an example.

  7. Life's Solution

    NASA Astrophysics Data System (ADS)

    Morris, Simon Conway

    2004-11-01

    Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3

  8. Life's Solution

    NASA Astrophysics Data System (ADS)

    Morris, Simon Conway

    2003-09-01

    Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3

  9. Processes in Verbal Analogy Solution.

    ERIC Educational Resources Information Center

    Grudin, Jonathan

    1980-01-01

    Verbal analogy solution is more flexible than is suggested by either the standard process theory or Sternberg's theory. It was determined that subjects initially examine terms A and B; if this strategy is not successful, they examine the relationship between A and C. (Author/CP)

  10. Determination of ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb in NORM products from oil and gas exploration: problems in activity underestimation due to the presence of metals and self-absorption of photons.

    PubMed

    Landsberger, S; Brabec, C; Canion, B; Hashem, J; Lu, C; Millsap, D; George, G

    2013-11-01

    Typical calibration of solid environmental samples for the determination of (226)Ra, (228)Ra and (210)Pb entails the use of standard reference materials which have a very similar matrix. However, TENORM samples from the oil and gas exploration contain unusually high amounts of calcium, strontium and barium which can severely attenuate the photons of (210)Pb and (226)Ra with their characteristic 46.1 keV and 186.2 keV gamma-rays, respectively and to some extent (228)Ra with the characteristic gamma-rays of 911.2 keV and 969.0 keV. We used neutron activation analysis to evaluate the content of TENORM for calcium, barium and strontium and then used a software program SELABS to determine the self-absorption. Our results confirm that even in Petrie containers with small dimensions the (210)Pb can be underestimated by almost by a factor of four while (226)Ra can be underestimated by 5%. The (228)Ra activities are virtually unaffected due to the higher energy gamma-rays. However, the implications for TENORM studies that employ large Marinelli containers having sample sizes between 0.25 and 1.0 L may be severely compromised by the presence of high Z elements in elevated concentrations. The usual spectral interferences on (226)Ra, (228)Ra and (210)Pb coming from other radionuclides in the (234)U, (235)U and (238)U decay chains are virtually nonexistent due the very high activity levels of (226)Ra, (228)Ra and (210)Pb in the tens of thousands of Bq/kg. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. High Standards or a High Standard of Standardness?

    ERIC Educational Resources Information Center

    McWilliam, Erica

    2010-01-01

    This paper explores the difference between "high standards" and a "high standard of standardness" of professional service provision in teacher-librarianship. That is to say, it explores the difference between a demonstrated deep commitment to 21st century learning ("high standards") and demonstrated compliance with a pre-determined checklist of…

  12. An address geocoding solution for Chinese cities

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehu; Ma, Haoming; Li, Qi

    2006-10-01

    We introduce the challenges of address geocoding for Chinese cities and present a potential solution along with a prototype system that deal with these challenges by combining and extending current geocoding solutions developed for United States and Japan. The proposed solution starts by separating city addresses into "standard" addresses which meet a predefined address model and non-standard ones. The standard addresses are stored in a structured relational database in their normalized forms, while a selected portion of the non-standard addresses are stored as aliases to the standard addresses. An in-memory address index is then constructed from the address database and serves as the basis for real-time address matching. Test results were obtained from two trials conducted in the city Beijing. On average 80% matching rate were achieved. Possible improvements to the current design are also discussed.

  13. Scalar field in standard cosmology: time equation.

    NASA Astrophysics Data System (ADS)

    Zecca, A.

    1999-11-01

    The separated time equation relative to the generalized Klein-Gordon equation in the Robertson-Walker space-time is integrated in the background of the standard cosmology. The solutions are given in terms of series that are obtained by the usual integration method of differential equations with regular singularity. The normalization of the solutions implied by the requirement of second quantization of the scalar field is performed. The result exhausts the requirement of providing an explicit complete set of normal mode solutions of the scalar field equation in standard cosmology.

  14. The Paperless Solution

    NASA Technical Reports Server (NTRS)

    2001-01-01

    REI Systems, Inc. developed a software solution that uses the Internet to eliminate the paperwork typically required to document and manage complex business processes. The data management solution, called Electronic Handbooks (EHBs), is presently used for the entire SBIR program processes at NASA. The EHB-based system is ideal for programs and projects whose users are geographically distributed and are involved in complex management processes and procedures. EHBs provide flexible access control and increased communications while maintaining security for systems of all sizes. Through Internet Protocol- based access, user authentication and user-based access restrictions, role-based access control, and encryption/decryption, EHBs provide the level of security required for confidential data transfer. EHBs contain electronic forms and menus, which can be used in real time to execute the described processes. EHBs use standard word processors that generate ASCII HTML code to set up electronic forms that are viewed within a web browser. EHBs require no end-user software distribution, significantly reducing operating costs. Each interactive handbook simulates a hard-copy version containing chapters with descriptions of participants' roles in the online process.

  15. Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards

    PubMed Central

    Bornstein, Marc H.; Jager, Justin; Putnick, Diane L.

    2014-01-01

    Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study’s target population, whether they yield representative and generalizable estimates of subsamples within a study’s target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce “noise” related to variation in subsamples and whether that “noise” can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting. PMID:25580049

  16. Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards.

    PubMed

    Bornstein, Marc H; Jager, Justin; Putnick, Diane L

    2013-12-01

    Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study's target population, whether they yield representative and generalizable estimates of subsamples within a study's target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce "noise" related to variation in subsamples and whether that "noise" can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting.

  17. A New Standard Pulsar Magnetosphere

    NASA Technical Reports Server (NTRS)

    Contopoulos, Ioannis; Kalapotharakos, Constantinos; Kazanas, Demosthenes

    2014-01-01

    In view of recent efforts to probe the physical conditions in the pulsar current sheet, we revisit the standard solution that describes the main elements of the ideal force-free pulsar magnetosphere. The simple physical requirement that the electric current contained in the current layer consists of the local electric charge moving outward at close to the speed of light yields a new solution for the pulsar magnetosphere everywhere that is ideal force-free except in the current layer. The main elements of the new solution are as follows: (1) the pulsar spindown rate of the aligned rotator is 23% larger than that of the orthogonal vacuum rotator; (2) only 60% of the magnetic flux that crosses the light cylinder opens up to infinity; (3) the electric current closes along the other 40%, which gradually converges to the equator; (4) this transfers 40% of the total pulsar spindown energy flux in the equatorial current sheet, which is then dissipated in the acceleration of particles and in high-energy electromagnetic radiation; and (5) there is no separatrix current layer. Our solution is a minimum free-parameter solution in that the equatorial current layer is electrostatically supported against collapse and thus does not require a thermal particle population. In this respect, it is one more step toward the development of a new standard solution. We discuss the implications for intermittent pulsars and long-duration gamma-ray bursts. We conclude that the physical conditions in the equatorial current layer determine the global structure of the pulsar magnetosphere.

  18. A new standard pulsar magnetosphere

    SciTech Connect

    Contopoulos, Ioannis; Kalapotharakos, Constantinos; Kazanas, Demosthenes

    2014-01-20

    In view of recent efforts to probe the physical conditions in the pulsar current sheet, we revisit the standard solution that describes the main elements of the ideal force-free pulsar magnetosphere. The simple physical requirement that the electric current contained in the current layer consists of the local electric charge moving outward at close to the speed of light yields a new solution for the pulsar magnetosphere everywhere that is ideal force-free except in the current layer. The main elements of the new solution are as follows: (1) the pulsar spindown rate of the aligned rotator is 23% larger than that of the orthogonal vacuum rotator; (2) only 60% of the magnetic flux that crosses the light cylinder opens up to infinity; (3) the electric current closes along the other 40%, which gradually converges to the equator; (4) this transfers 40% of the total pulsar spindown energy flux in the equatorial current sheet, which is then dissipated in the acceleration of particles and in high-energy electromagnetic radiation; and (5) there is no separatrix current layer. Our solution is a minimum free-parameter solution in that the equatorial current layer is electrostatically supported against collapse and thus does not require a thermal particle population. In this respect, it is one more step toward the development of a new standard solution. We discuss the implications for intermittent pulsars and long-duration gamma-ray bursts. We conclude that the physical conditions in the equatorial current layer determine the global structure of the pulsar magnetosphere.

  19. Assessing Natural Radionuclide Migration in the Legacy Tailings of Uranium Production

    NASA Astrophysics Data System (ADS)

    Bondarenko, G.; Koliabina, I.; Marinich, O.

    2011-12-01

    The former Prydniprovsky Chemical Plant in Dniprodzerzhynsk, Ukraine, processed uranium ore from 1949 until 1991. Multiple tailing ponds containing solid residual waste products from the uranium leaching and processing of uranium were accumulated along the Dnieper River, including the largest, adjacent to the Dnieper Reservoir, containing over 12 million tons of tailings. Samples for this study were selected from a core recovered from the Dnieper tailing pit in 2009, and used to assess radionuclide migration from tailing ponds. Samples were selected from different depths of the tailing pit core, analyzed for total radionuclide concentrations [Marinich et al., 2009], and successively leached using distilled water, followed by 1N ammonium acetate solution, and finally by 1N HCl solution. Leaching times were ~24 h at 15.17 °C. 238U, 230Th and 226Ra leachate activities were measured by γ-spectrometry with a Ge(Li) detector. 210Pb activity was measured using a SEB-01 scintillation β-spectrometer. Errors depended on measuring method, radionuclide, activity and exposure time: 238U, 11.9%; 230Th, 10.9%; 226Ra, 9.3%; 210Pb ~30%. The average total 238U activity in the tailing profile was 4 Bq/g. The concentration of 238U in the water leachates increased with depth from 14.5% (7-7.5 m), to 43% (11-11.5 m). The concentration of 238U in the acid leachates behaved similarly, increasing from 5.5 % to 15.5% with depth. While the total 230Th activity in increased from 30 Bq/g (7-7.5 m) to 540 Bq/g (11-11.5 m), the 230Th concentration in ammonium acetate leachates decreased from ˜15% to ˜1%. The concentration of 226Ra in all leachates was <1%, indicating that, under conditions of the Dnieper tailing pit, 226Ra is essentially immobile. The concentration of 210Pb in the leachates was as high as 10%. In general, the magnitude of mobile activity from the Dnieper tailing pit core samples decreases in the order 238U>230Th≥210Pb> 226Ra. Secular radioactive equilibrium in the 238U

  20. Beyond Standardization: State Standards and School Improvement.

    ERIC Educational Resources Information Center

    Darling-Hammond, Linda; Wise, Arthur E.

    1985-01-01

    Focuses on how state policies affect the teacher-learner relationship in classrooms. Particular attention is given to standard setting as implemented through testing mechanisms. With respect to students, test-based standards as well as test-based instructional processes are examined. With respect to teachers, test-based standards for professional…

  1. Standards for Standardized Logistic Regression Coefficients

    ERIC Educational Resources Information Center

    Menard, Scott

    2011-01-01

    Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

  2. Standards for Standardized Logistic Regression Coefficients

    ERIC Educational Resources Information Center

    Menard, Scott

    2011-01-01

    Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

  3. Mathematics Content Standards Benchmarks and Performance Standards

    ERIC Educational Resources Information Center

    New Mexico Public Education Department, 2008

    2008-01-01

    New Mexico Mathematics Content Standards, Benchmarks, and Performance Standards identify what students should know and be able to do across all grade levels, forming a spiraling framework in the sense that many skills, once introduced, develop over time. While the Performance Standards are set forth at grade-specific levels, they do not exist as…

  4. Farm Financial Standards.

    PubMed

    McGrann, J M

    1995-07-01

    The Farm Financial Standards were developed by a national effort to encourage standardization. Standardization includes financial statement formats, terminology, and calculations for measuring financial position and format. Comparative analysis and education efforts are enhanced greatly by standardization. The Standardization Performance Analysis (SPA) system was developed on the basis of the performance standards for beef cattle and sheep enterprises. This article summarizes the Farm Financial Standards and illustrates the calculations with a worksheet.

  5. Plagiarism Detection by Online Solutions.

    PubMed

    Masic, Izet; Begic, Edin; Dobraca, Amra

    2017-01-01

    The problem of plagiarism represents one of the burning issues of the modern scientific world. Detection of plagiarism is a problem that the Editorial Board encounters in their daily work. Software solutions represent a good solution for the detection of plagiarism. The problem of plagiarism will become most discussed topic of the modern scientific world, especially due to the development of standard measures, which rank the work of one author. Investment in education, education of young research personnel about the importance of scientific research, with paying particular attention on ethical behavior, becomes an imperative of academic staff. Editors have to invest additional effort in the development of the base of reviewers team as well as in their proper guidance, because after all, despite the software solutions, they are the best weapon to fight plagiarism. Peer review process should be a key of successful operation of each journal.

  6. Radiation Driven Wind Solutions and Applications

    NASA Astrophysics Data System (ADS)

    Curé, M.

    2016-11-01

    The standard modified-CAK equation of motion is a non-linear differential equation that possesses many singular points and therefore many solutions. Apart from the standard solution, we have found three other physical solutions: i) when the rotational velocity is higher than 3/4 of the critical rotational speed; ii) when there is a high ionization change throughout the wind; and iii) when the k line force parameter is very high (k is the fraction of the total stellar flux which would be blocked in the photosphere if all lines were optically thick). We also show some applications of these solutions, e.g., the wind of a B[e] supergiant, the oblate wind of a Be star, and the winds of BA supergiants. Furthermore, we calculate synthetic spectra with FASTWIND, where we have used our new hydrodynamical solutions as input to the code.

  7. Standards 101: The ASA Standards program

    NASA Astrophysics Data System (ADS)

    Schomer, Paul

    2001-05-01

    ASA serves as a standards developer under the auspices of the American National Standards Institute (ANSI). The Standards Program is organized through four technical committees (S1, S2, S3, and S12) and one administrative committee (ASACOS). S1 deals with physical acoustics, S2 deals with shock and vibration, S3 deals with physiological and psychological acoustics and S12 deals with noise. ASACOS is the ASA Committee on Standards. The program has three primary tasks: (1) development of national standards (ANSI Standards), (2) national adoption of international standards (ANSI NAIS Standards), (3) providing the USA input to the development of international standards (ISO and IEC Standards). At every level the main work is accomplished in Working Groups (WG) that are staffed by hundreds of volunteers, mainly ASA members from its various technical committees such as Noise, Physical Acoustics, Architectural Acoustics, Physiological and Psychological Acoustics, etc. Overall, the Standards Program involves more ASA members than does any other single function of the society except meetings. It is the biggest outreach function of ASA affecting the health, welfare, and economic well-being of large sectors of society. It is a main way the ASA diffuses the knowledge of acoustics and its practical application, perhaps the main way.

  8. Standards 101; the ASA standards program

    NASA Astrophysics Data System (ADS)

    Schomer, Paul D.

    2002-11-01

    ASA supports the development of standards by serving as the secretariat for standards committees of the American National Standards Institute (ANSI). The program is organized through four ANSI technical committees (S1, S2, S3, and S12) and one administrative committee (ASACOS). S1 deals with physical acoustics, S2 deals with shock and vibration, S3 deals with physiological and psychological acoustics, and S12 deals with noise. ASACOS is the ASA Committee on Standards. The program has three primary tasks: (1) the development of National Standards (ANSI Standards), (2) the national adoption of an international standard (ANSI NAIS Standards), (3) providing the USA input to the development of International Standards (ISO and IEC Standards). At every level the main work is accomplished in Working Groups (WG) that are ''staffed'' by hundreds of volunteers--mainly ASA members from its various technical committees such as Noise, Physical Acoustics, Architectural Acoustics, Psychological and Physiological Acoustics, etc. Overall, the Standards Program involves more ASA members than does any other single function of the Society except meetings and it is the biggest outreach function of ASA affecting the health, welfare, and economic well-being of large segments of the population, the business and industrial community, and government at all levels.

  9. Standards 101: The ASA Standards program

    NASA Astrophysics Data System (ADS)

    Schomer, Paul

    2004-05-01

    ASA serves as a standards developer under the auspices of the American National Standards Institute (ANSI). The Standards Program is organized through four technical committees (S1, S2, S3, and S12) and one administrative committee (ASACOS). S1 deals with physical acoustics, S2 deals with shock and vibration, S3 deals with physiological and psychological acoustics and S12 deals with noise. ASACOS is the ASA Committee on Standards. The program has three primary tasks: (1) development of national standards (ANSI Standards), (2) national adoption of international standards (ANSI NAIS Standards), (3) providing the USA input to the development of international standards (ISO and IEC Standards). At every level the main work is accomplished in Working Groups (WG) that are staffed by hundreds of volunteers, mainly ASA members from its various technical committees such as Noise, Physical Acoustics, Architectural Acoustics, Physiological and Psychological Acoustics, etc. Overall, the Standards Program involves more ASA members than does any other single function of the society except meetings. It is the biggest outreach function of ASA affecting the health, welfare, and economic well-being of large sectors of society. It is a main way the ASA diffuses the knowledge of acoustics and its practical application, perhaps the main way.

  10. Relaxation solution of the full Euler equations

    NASA Technical Reports Server (NTRS)

    Johnson, G. M.

    1982-01-01

    A numerical procedure for the relaxation solution of the full steady Euler equations is described. By embedding the Euler system in a second order surrogate system, central differencing may be used in subsonic regions while retaining matrix forms well suited to iterative solution procedures and convergence acceleration techniques. Hence, this method allows the development of stable, fully conservative differencing schemes for the solution of quite general inviscid flow problems. Results are presented for both subcritical and shocked supercritical internal flows. Comparisons are made with a standard time dependent solution algorithm.

  11. Relaxation solution of the full Euler equations

    NASA Technical Reports Server (NTRS)

    Johnson, G. M.

    1982-01-01

    A numerical procedure for the relaxation solution of the full steady Euler equations is described. By embedding the Euler system in a second order surrogate system, central differencing may be used in subsonic regions while retaining matrix forms well suited to iterative solution procedures and convergence acceleration techniques. Hence, this method allows the development of stable, fully conservative differencing schemes for the solution of quite general inviscid flow problems. Results are presented for both subcritical and shocked supercritical internal flows. Comparisons are made with a standard time dependent solution algorithm. Previously announced in STAR as N82-24859

  12. 1993 DOE technical standards managers workshop: Proceedings

    SciTech Connect

    Not Available

    1993-12-31

    This workshop is focused on the benefits of the DOE technical standards program, which is focused toward the preferred use of non-Government standards for DOE activities and the development of DOE technical standards when non-Government standards are not available or are inappropriate. One goal of the program is to replace redundant site-specific standards with more universally accepted documents that have been scrutinized by experts. This replacement is discussed at the workshop along with the problems encountered and solutions found. The workshop provided an opportunity for geographically dispersed people to meet and advance their standards knowledge and efforts to support the program. Safety issues have been the driving force behind the program to date. Several companies offer products and services that support the development, processing, and retrieval of standards. This document mostly comprise vugraphs.

  13. A modified Lowry protein test for dilute protein solutions

    Treesearch

    Garold F. Gregory; Keith F. Jensen

    1971-01-01

    A modified Lowry protein test for dilute protein solutions modified Lowry protein test was compared with the standard Lowry protein test. The modified test was found to give estimates of protein concentration that were as good as the standard test and has the advange that proteins can be measured in very dilute solutions.

  14. Stability of aflatoxins in solution.

    PubMed

    Diaz, Gonzalo J; Cepeda, Sandra M; Martos, Perry A

    2012-01-01

    The stability of aflatoxins B1, B2, G1, and G2 was studied in solutions containing different concentrations of water, acetonitrile, and/or methanol, and in autosampler vials treated with nitric acid or silanized. When stored at room temperature (20 degrees C) for 24 h, aflatoxins G1 and G2 were stable only in solutions containing 100% organic solvent, whereas aflatoxins B1 and B2 were stable in solutions of methanol-water and acetonitrile-water at greater than 60 and 40% organic content, respectively. At 5 degrees C, aflatoxins G1 and G2 showed a significant decrease in concentration only when kept in less than 20% aqueous organic solvent. Significant loss of aflatoxins was realized in standard, commercially available amber type I borosilicate autosampler vials, but chemical etching of the vials with nitric acid or with silanization prevented aflatoxin degradation. These results indicate that aflatoxins are unstable in aqueous solutions and that this instability can be counteracted by the presence of at least 20% organic solvent and keeping the solutions at 5 degrees C or by the use of treated vials.

  15. Theoretical evaluation of the 222Rn emanation coefficient for coal fly ash.

    PubMed

    Maraziotis, E A

    1987-03-01

    The release of 222Rn, from individual material grains in which it is formed, may be largely a diffusion process. This paper presents an analytical model purporting to describe the physical process of the release of 222Rn atoms from a 226Ra-bearing material grain. The solution of the diffusion equation for a spherical grain permits us to calculate theoretically the diffusion and emanation coefficient. Using this analysis to interpret experimental release data is explained.

  16. SU(5) heterotic Standard Model bundles

    NASA Astrophysics Data System (ADS)

    Andreas, Björn; Hoffmann, Norbert

    2012-04-01

    We construct a class of stable SU(5) bundles on an elliptically fibered Calabi-Yau threefold with two sections, a variant of the ordinary Weierstrass fibration, which admits a free involution. The bundles are invariant under the involution, solve the topological constraint imposed by the heterotic anomaly equation and give three generations of Standard Model fermions after symmetry breaking by Wilson lines of the intermediate SU(5) GUT-group to the Standard Model gauge group. Among the solutions we find some which can be perturbed to solutions of the Strominger system. Thus these solutions provide a step toward the construction of phenomenologically realistic heterotic flux compactifications via non-Kähler deformations of Calabi-Yau geometries with bundles. This particular class of solutions involves a rank two hidden sector bundle and does not require background fivebranes for anomaly cancellation.

  17. Controlled diffusion for laboratory solution preparation.

    PubMed

    Yoshida, Makoto; Tohda, Koji; Gratzl, Miklós

    2008-10-01

    We report here on a method for preparation of precise laboratory solutions using controlled diffusion for dosing. The desired chemical is delivered into the target solution from a stock solution through a mass-transport-limiting delivery port that blocks convection but allows reproducible diffusive transport. Solution making with this approach involves a single step irrespective of how low the desired concentration is. Diffusional delivery of chemicals involves no appreciable movement of water and, thus, no addition of volume. The approach is therefore particularly suitable for standard addition. Precise solutions of usual laboratory volumes can be made within a short time period with proper design of the delivery port or ports. Comparison with the performance of conventional methods of routine solution preparation shows that better precision can be achieved with less labor using this approach.

  18. Real-World Problems: Teachers' Evaluation of Pupils' Solutions

    ERIC Educational Resources Information Center

    Chacko, Indira

    2007-01-01

    This article scrutinizes the solutions of real-world problems by pupils and the evaluations of these by their teachers in a semi-rural school in Zimbabwe. Generally, real-world problems are solved as if these are standard problems expecting a solution and a correct answer. In most cases, the solutions of the pupils are considered correct by the…

  19. 40 CFR 792.83 - Reagents and solutions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Reagents and solutions. 792.83 Section... ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 792.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be labeled to indicate identity,...

  20. 40 CFR 160.83 - Reagents and solutions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Reagents and solutions. 160.83 Section... LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and... requirements, and expiration date. Deteriorated or outdated reagents and solutions shall not be used....

  1. 40 CFR 160.83 - Reagents and solutions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Reagents and solutions. 160.83 Section... LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be labeled to indicate identity, titer or concentration,...

  2. 40 CFR 160.83 - Reagents and solutions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Reagents and solutions. 160.83 Section... LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be labeled to indicate identity, titer or concentration,...

  3. 40 CFR 160.83 - Reagents and solutions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Reagents and solutions. 160.83 Section... LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be labeled to indicate identity, titer or concentration,...

  4. 40 CFR 160.83 - Reagents and solutions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Reagents and solutions. 160.83 Section... LABORATORY PRACTICE STANDARDS Testing Facilities Operation § 160.83 Reagents and solutions. All reagents and solutions in the laboratory areas shall be labeled to indicate identity, titer or concentration,...

  5. Static Solutions of Einstein's Equations with Cylindrical Symmetry

    ERIC Educational Resources Information Center

    Trendafilova, C. S.; Fulling, S. A.

    2011-01-01

    In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well-known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the spacetime is…

  6. Static Solutions of Einstein's Equations with Cylindrical Symmetry

    ERIC Educational Resources Information Center

    Trendafilova, C. S.; Fulling, S. A.

    2011-01-01

    In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well-known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the spacetime is…

  7. International Standardization of Bed Rest Standard Measures

    NASA Technical Reports Server (NTRS)

    Cromwell, Ronita L.

    2010-01-01

    This slide presentation gives an overview of the standardization of bed rest measures. The International Countermeasures Working Group attempted to define and agree internationally on standard measurements for spaceflight based bed rest studies. The group identified the experts amongst several stakeholder agencys. It included information on exercise, muscle, neurological, psychological, bone and cardiovascular measures.

  8. Beyond Standardization: State Standards and School Improvement.

    ERIC Educational Resources Information Center

    Wise, Arthur E.; Darling-Hammond, Linda

    This paper focuses on ways in which one state policy for improving education--standard-setting through testing mechanisms--affects the classroom teacher-learner relationship. That uniform policy-making is problematic is clear from observations of 43 Mid-Atlantic school district teachers. Responding to three types of standards, 45 percent found…

  9. Generation and evolution of magma beneath the East Pacific Rise: Constraints from U-series disequilibrium and plagioclase-hosted melt inclusions

    NASA Astrophysics Data System (ADS)

    Zhang, Guo-Liang; Zeng, Zhi-Gang; Beier, Christoph; Yin, Xue-Bo; Turner, Simon

    2010-06-01

    Mid-ocean ridge basalt (MORB) samples from the East Pacific Rise (EPR 12°50'N) were analyzed for U-series isotopes and compositions of plagioclase-hosted melt inclusions. The 226Ra and 230Th excesses are negatively correlated; the 226Ra excess is positively correlated with Mg# and Sm/Nd, and is negatively correlated with La/Sm and Fe 8; the 230Th excess is positively correlated with Fe 8 and La/Sm and is negatively correlated with Mg# and Sm/Nd. Interpretation of these correlations is critical for understanding the magmatic process. There are two models (the dynamic model and the "two-porosity" model) for interpreting these correlations, however, some crucial parameters used in these models are not ascertained. We propose instead a model to explain the U-series isotopic compositions based on the control of melt density variation. For melting either peridotite or the "marble-cake" mantle, the FeO t content, 230Th excess and La/Sm ratio increases and Sm/Nd decreases with increasing pressure. A deep melt will evolve to a higher density and lower Mg# than a shallow melt, the former corresponds to a long residence time, which lowers the 226Ra excess significantly. This model is supported by the existence of low 226Ra excesses and high 230Th excesses in MORBs having a high Fe 8 content and high density. The positive correlation of 226Ra excess and magma liquidus temperature implies that the shallow melt is cooled less than the deep melt due to its low density and short residence time. The correlations among Fe 8, Ti 8 and Ca 8/Al 8 in plagioclase-hosted melt inclusions further prove that MORBs are formed from melts having a negative correlation in melting depths and degrees. The negative correlation of 226Ra excess vs. chemical diversity index (standard deviation of Fe 8, Ti 8 and Ca 8/Al 8) of the melt inclusions is in accordance with the influence of a density-controlled magma residence time. We conclude that the magma density variation exerts significant control on

  10. Arizona Academic Standards, Kindergarten

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2007

    2007-01-01

    This publication contains Arizona public schools' academic standards for kindergarten. The contents of this document include the following: (1) The Arts Standard 2006--Kindergarten; (2) Comprehensive Health Education/Physical Activity Standards 1997--Readiness (Kindergarten); (3) Foreign and Native Language Standards 1997--Essentials (Grades 4-8);…

  11. Standards for holdup measurement

    SciTech Connect

    Zucker, M.S.

    1982-01-01

    Holdup measurement, needed for material balance, depend intensively on standards and on interpretation of the calibration procedure. More than other measurements, the calibration procedure using the standard becomes part of the standard. Standards practical for field use and calibration techniques have been developed. While accuracy in holdup measurements is comparatively poor, avoidance of bias is a necessary goal.

  12. Arizona Academic Standards: Kindergarten

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2009

    2009-01-01

    This publication contains Arizona public schools' academic standards for kindergarten. The contents of this document include the following: (1) The Arts Standard 2006--Kindergarten; (2) Comprehensive Health Education/Physical Activity Standards 1997--Readiness (Kindergarten); (3) Foreign and Native Language Standards 1997--Readiness…

  13. ACOUSTICAL STANDARDS NEWS

    PubMed Central

    Stremmel, Neil B.; Struck, Christopher J.

    2017-01-01

    American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, S3/SC 1, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, animal bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes a catalog of Acoustical American National Standards. To receive a copy of the latest Standards catalog, please contact Neil Stremmel. Comments are welcomed on all material in Acoustical Standards News. This Acoustical Standards News section in JASA, as well as the national catalog of Acoustical Standards and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org. PMID:28599517

  14. Plutonium solution analyzer

    SciTech Connect

    Burns, D.A.

    1994-09-01

    A fully automated analyzer has been developed for plutonium solutions. It was assembled from several commercially available modules, is based upon segmented flow analysis, and exhibits precision about an order of magnitude better than commercial units (0.5%-O.05% RSD). The system was designed to accept unmeasured, untreated liquid samples in the concentration range 40-240 g/L and produce a report with sample identification, sample concentrations, and an abundance of statistics. Optional hydraulics can accommodate samples in the concentration range 0.4-4.0 g/L. Operating at a typical rate of 30 to 40 samples per hour, it consumes only 0.074 mL of each sample and standard, and generates waste at the rate of about 1.5 mL per minute. No radioactive material passes through its multichannel peristaltic pump (which remains outside the glovebox, uncontaminated) but rather is handled by a 6-port, 2-position chromatography-type loop valve. An accompanying computer is programmed in QuickBASIC 4.5 to provide both instrument control and data reduction. The program is truly user-friendly and communication between operator and instrument is via computer screen displays and keyboard. Two important issues which have been addressed are waste minimization and operator safety (the analyzer can run in the absence of an operator, once its autosampler has been loaded).

  15. 1996 DOE technical standards program workshop: Proceedings

    SciTech Connect

    1996-07-01

    The workshop theme is `The Strategic Standardization Initiative - A Technology Exchange and Global Competitiveness Challenge for DOE.` The workshop goal is to inform the DOE technical standards community of strategic standardization activities taking place in the Department, other Government agencies, standards developing organizations, and industry. Individuals working on technical standards will be challenged to improve cooperation and communications with the involved organizations in response to the initiative. Workshop sessions include presentations by representatives from various Government agencies that focus on coordination among and participation of Government personnel in the voluntary standards process; reports by standards organizations, industry, and DOE representatives on current technology exchange programs; and how the road ahead appears for `information superhighway` standardization. Another session highlights successful standardization case studies selected from several sites across the DOE complex. The workshop concludes with a panel discussion on the goals and objectives of the DOE Technical Standards Program as envisioned by senior DOE management. The annual workshop on technical standards has proven to be an effective medium for communicating information related to standards throughout the DOE community. Technical standards are used to transfer technology and standardize work processes to produce consistent, acceptable results. They provide a practical solution to the Department`s challenge to protect the environment and the health and safety of the public and workers during all facility operations. Through standards, the technologies of industries and governments worldwide are available to DOE. The DOE Technical Standards Program, a Department-wide effort that crosscuts all organizations and disciplines, links the Department to those technologies.

  16. A Calibration and Quality Assurance Program for Environmental Radon Measurements

    PubMed Central

    Fisenne, Isabel M.; George, Andreas C.; Keller, Helen W.

    1990-01-01

    The ideal facility for assessing the quality of radon measurements at environmental levels consists of: (1) an instrument whose response to radon and its progeny is determined from measurements of a certified or standard 226Ra source, and (2) a calibration room with a known radon concentration. The linkage between these two elements and additional quality control requirements are discussed here for some Environmental Measurements Laboratory radon measurements programs. PMID:28179764

  17. Telemetry Standards, Part 1

    DTIC Science & Technology

    2015-07-01

    Telemetry Standards, IRIG Standard 106-15 (Part 1), Table of Contents, July 2015 TELEMETRY GROUP IRIG STANDARD 106-15 PART 1... TELEMETRY STANDARDS DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE DISTRIBUTION IS UNLIMITED ABERDEEN TEST CENTER DUGWAY PROVING GROUND...JUL 2015 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Telemetry Standards, Part 1 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  18. Standards for contamination control

    NASA Astrophysics Data System (ADS)

    Borson, Eugene N.

    2004-10-01

    Standards are an important component of national and international trade. We depend upon standards to assure that manufactured parts will work together, wherever they are made, and that we speak the same technical language, no matter what language we speak. Understanding is important in order to know when to take exceptions to or tailor the standard to fit the job. Standards that are used in contamination control have increased in numbers over the years as more industries have had to improve their manufacturing processes to enhance reliability or yields of products. Some older standards have been revised to include new technologies, and many new standards have been developed. Some of the new standards were written for specific industries while others apply to many industries. Many government standards have been replaced with standards from nongovernmental standards organizations. This trend has been encouraged by U.S. law that requires the government to use commercial standards where possible. This paper reviews some of the more important standards for the aerospace industry, such as IEST-STD-CC1246 and ISO 14644-1, that have been published in recent years. Benefits, usage, and problems with some standards will be discussed. Some standards are referenced, and websites of some standards organizations are listed.

  19. [Humanitarian action threatened by standardization].

    PubMed

    Mamou, J

    2002-01-01

    The author analyses the new international context in which humanitarian action is being undertaken. He raises the problem caused by the diverging objectives of impartial, neutral humanitarianism and politically motivated actions that implement strategies of prevention and conflict resolution. He reviews the criticism that humanitarian has come under in recent years and that has resulted in establishment of codes of conduct. However he points out the threat that the concepts of control and "jurisdiction" over humanitarian action represent and analyzes discrepancies between minimal standards and universal principles. The article concludes with a presentation of an alternative solution based on the "Quality" platform being developed by several French NGOs.

  20. Dissolution of alkaline earth sulfates in the presence of montmorillonite

    USGS Publications Warehouse

    Eberl, D.D.; Landa, E.R.

    1985-01-01

    In a study of the effect of montmorillonite on the dissolution of BaSO4 (barite), SrSO4 (celestite), and 226Ra from U mill tailings, it was found that: (1) More of these substances dissolve in an aqueous system that contains montmorillonite than dissolve in a similar system without clay, due to the ion exchange properties of the clay; (2) Na-montmorillonite is more effective in aiding dissolution than is Ca-montmorillonite; (3) the amount of Ra that moves from mill tailings to an exchanger increases as solution sulfate activity decreases. Leaching experiments suggest that 226Ra from H2SO4-circuit U mill tailings from Edgemont, South Dakota, is not present as pure Ra sulfate or as an impurity in anhydrite or gypsum; it is less soluble, and probably occurs as a trace constituent in barite.

  1. Lead-210, polonium-210, manganese and iron in the Cariaco Trench

    NASA Astrophysics Data System (ADS)

    Bacon, Michael P.; Brewer, Peter G.; Spencer, Derek W.; Murray, James W.; Goddard, John

    1980-02-01

    Measurements of temperature, salinity, dissolved oxygen, sulfide, 226Ra, Mn, Fe, 210Pb, 210Po, and total suspended matter from three cruises of R.V. Atlantis II in the Cariaco Trench are reported. Distributions of dissolved and particulate Mn and Fe are similar to those for the Black Sea and reflect similar diffusion and redox-potential controls. Results for 210Pb and 226Ra in the anoxic deep water indicate a residence time for 210Pb in solution of less than two years. Particulate 210Pb results suggest that removal occurs largely by incorporation into metal sulfide phases forming in the water column. There is also evidence for precipitation of 210Pb with manganese oxide or iron hydroxide just above the O 2-H 2S interface. In the upper 300 m, 210Po is enriched by 55% over radioactive equilibrium with 210Pb. Possible sources of this excess include the bottom sediments and the water upwelling along the Venezuelan coast.

  2. CERN single sign on solution

    NASA Astrophysics Data System (ADS)

    Ormancey, E.

    2008-07-01

    The need for Single Sign On has always been restricted by the absence of cross platform solutions: a single sign on working only on one platform or technology is nearly useless. The recent improvements in Web Services Federation (WS-Federation) standard enabling federation of identity, attribute, authentication and authorization information can now provide real extended Single Sign On solutions. Various solutions have been investigated at CERN and now, a Web SSO solution using some parts of WS-Federation technology is available. Using the Shibboleth Service Provider module for Apache hosted web sites and Microsoft ADFS as the identity provider linked to Active Directory user, users can now authenticate on any web application using a single authentication platform, providing identity, user information (building, phone...) as well as group membership enabling authorization possibilities. A typical scenario: a CERN user can now authenticate on a Linux/Apache website using Windows Integrated credentials, and his Active Directory group membership can be checked before allowing access to a specific web page.

  3. Standards, Standards, Standards: The Unintended Consequences of Widening Participation?

    ERIC Educational Resources Information Center

    Stuart, Mary

    2002-01-01

    Debate over widening access to higher education is narrowing to a focus on preservation of standards. Examination of the discourses of school policy, classroom environment, and peer culture shows how these competing cultures can work against efforts to increase participation. (Contains 17 references.) (SK)

  4. Economics of automobile fuel-economy standards

    SciTech Connect

    Kleit, A.N.

    1987-01-01

    Since 1978 the Federal government has mandated that new automobiles sold by major firms in the United States reach certain levels of average fuel efficiency. Corporate Average Fuel Economy (CAFE) standards can generate implicit taxes and subsidies for various types of cars. They also can have an impact on market structure, creating regulatory economies of scope. CAFE standards may also act to increase the profits of firms in the automobile industry, either by preventing competition among firms constrained by the standards or by creating profit opportunities for firms not constrained by the standards. CAFE standards are shown to have had a significant effect on the price of new cars in model years 1983 through 1986, raising the price of fuel inefficient cars and lowering the price of fuel efficient cars. The gasoline savings resulting from the imposition of higher standards are computed, as well as the welfare loss they generate. It is concluded that automobile fuel economy standards can save gasoline,but only at a large loss to the economy. An empirical model of the political support for CAFE standards is developed and tested. It is shown that support for the standards comes from the one major domestic automobile company that would benefit from higher standards, as well as from those who in general prefer regulatory solutions to the free market.

  5. Water Quality Standards Handbook

    EPA Pesticide Factsheets

    The Water Quality Standards Handbook is a compilation of the EPA's water quality standards (WQS) program guidance including recommendations for states, authorized tribes, and territories in reviewing, revising, and implementing WQS.

  6. Medical Assisting Program Standards.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the medical assisting program in Georgia. The standards are divided into 12 categories; Foundations (philosophy, purpose, goals, program objectives, availability, evaluation); Admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning); Program…

  7. Radiologic Technology Program Standards.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the radiologic technology program in Georgia. The standards are divided into 12 categories; Foundations (philosophy, purpose, goals, program objectives, availability, evaluation); Admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning); Program…

  8. Terahertz absorption of lysozyme in solution

    NASA Astrophysics Data System (ADS)

    Martin, Daniel R.; Matyushov, Dmitry V.

    2017-08-01

    Absorption of radiation by solution is described by its frequency-dependent dielectric function and can be viewed as a specific application of the dielectric theory of solutions. For ideal solutions, the dielectric boundary-value problem separates the polar response into the polarization of the void in the liquid, created by the solute, and the response of the solute dipole. In the case of a protein as a solute, protein nuclear dynamics do not project on significant fluctuations of the dipole moment in the terahertz domain of frequencies and the protein dipole can be viewed as dynamically frozen. Absorption of radiation then reflects the interfacial polarization. Here we apply an analytical theory and computer simulations to absorption of radiation by an ideal solution of lysozyme. Comparison with the experiment shows that Maxwell electrostatics fails to describe the polarization of the protein-water interface and the "Lorentz void," which does not anticipate polarization of the interface by the external field (no surface charges), better represents the data. An analytical theory for the slope of the solution absorption against the volume fraction of the solute is formulated in terms of the cavity field response function. It is calculated from molecular dynamics simulations in good agreement with the experiment. The protein hydration shell emerges as a separate sub-ensemble, which, collectively, is not described by the standard electrostatics of dielectrics.

  9. Terahertz absorption of lysozyme in solution.

    PubMed

    Martin, Daniel R; Matyushov, Dmitry V

    2017-08-28

    Absorption of radiation by solution is described by its frequency-dependent dielectric function and can be viewed as a specific application of the dielectric theory of solutions. For ideal solutions, the dielectric boundary-value problem separates the polar response into the polarization of the void in the liquid, created by the solute, and the response of the solute dipole. In the case of a protein as a solute, protein nuclear dynamics do not project on significant fluctuations of the dipole moment in the terahertz domain of frequencies and the protein dipole can be viewed as dynamically frozen. Absorption of radiation then reflects the interfacial polarization. Here we apply an analytical theory and computer simulations to absorption of radiation by an ideal solution of lysozyme. Comparison with the experiment shows that Maxwell electrostatics fails to describe the polarization of the protein-water interface and the "Lorentz void," which does not anticipate polarization of the interface by the external field (no surface charges), better represents the data. An analytical theory for the slope of the solution absorption against the volume fraction of the solute is formulated in terms of the cavity field response function. It is calculated from molecular dynamics simulations in good agreement with the experiment. The protein hydration shell emerges as a separate sub-ensemble, which, collectively, is not described by the standard electrostatics of dielectrics.

  10. International dental standards.

    PubMed

    Jones, Derek W

    2007-09-22

    International dental standards are vital in maintaining the safety and quality of both the products and materials used by dental professionals and the many oral health products used by members of the general public, yet many dentists will be unaware of the role standards play in their daily practice. In this article, Derek W. Jones outlines the vital work of the International Standards Organization and highlights how standards pervade nearly every dental procedure.

  11. A standardized nursing mathematics competency program.

    PubMed

    Middleton, Debra A

    2008-01-01

    Mathematics competency in nursing is an ongoing problem. The author discusses a standardized mathematics competency program based on current practices reported in nursing literature. Dimensional analysis is the method that students learn to find solutions to nursing problems that require mathematics and is important to the success of the program.

  12. Stricter clean air standards

    SciTech Connect

    Schell, D.

    1997-07-01

    New standards for ozone and particulate matter stir a debate between the EPA and industrial groups. The article discusses both the history of the ozone and particulates standards, the goal of the EPA to protect health and evaluation of what the standards mean to health, and the industrial response.

  13. Standards for Objective Tests

    ERIC Educational Resources Information Center

    Tristan, Agustin; Vidal, Rafael

    2007-01-01

    A new book of standards for quality of tests has been published in Spanish, filling a gap on this field. The book includes 64 standards, comments, a companion questionnaire for self-evaluation and a planning schedule; with those tools a non-expert may understand the standards, and easily follow some procedures to design or to improve a test. The…

  14. Standards and Certification. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers from a symposium on standards and certification in human resource development (HRD). "Implementing Management Standards in the UK" (Jonathan Winterton, Ruth Winterton) reports on a study that explored the implementation of management standards in 16 organizations and identified 36 key themes and…

  15. Emission Standards for Particulates

    ERIC Educational Resources Information Center

    Walsh, George W.

    1974-01-01

    Promulgation of standards of performance under Section 111 and national emission standards for hazardous pollutants under Section 112 of the Clean Air Act is the responsibility of the Emission Standards and Engineering Division of the Environmental Protection Agency. The problems encountered and the bases used are examined. (Author/BT)

  16. New Coal Standards.

    ERIC Educational Resources Information Center

    Heritage, John

    1979-01-01

    Tighter federal air pollution control standards for new coal-burning electric power plants have been issued. Through use of air pollution control devices all types of coal will be useable under the new standards. Even stricter standards may be imposed where visibility may be affected in areas now enjoying very clean air. (RE)

  17. Language Standardization and Education.

    ERIC Educational Resources Information Center

    Rubin, Joan

    This paper discusses the problem of language standardization in education. The areas to which standardization may refer - phonology, spelling, punctuation, grammar and lexicon - are discussed, and problems associated with efforts to standardize them in schools are pointed out. The position taken is that a decision to promote language standards…

  18. Library Technician Skill Standards.

    ERIC Educational Resources Information Center

    Highline Community Coll., Des Moines, WA.

    This document presents skill standards for library technicians. Introductory sections describe the industry and the job, what skill standards are, how the library technician skill standards were developed, employability skills and critical competencies, and the SCANS (Secretary's Commission on Achieving Necessary Skills) foundation skills profile.…

  19. ALA Standards Manual.

    ERIC Educational Resources Information Center

    American Library Association, Chicago, IL. Committee on Standards.

    This American Library Association (ALA) policy statement and procedure manual is intended for use in the preparation of all standards issued by ALA and its component units to insure coordination of format and correlation of content of ALA standards. A brief discussion of the purpose of standards is offered, followed by definitions of four types of…

  20. Automotive Technology Skill Standards

    ERIC Educational Resources Information Center

    Garrett, Tom; Asay, Don; Evans, Richard; Barbie, Bill; Herdener, John; Teague, Todd; Allen, Scott; Benshoof, James

    2009-01-01

    The standards in this document are for Automotive Technology programs and are designed to clearly state what the student should know and be able to do upon completion of an advanced high-school automotive program. Minimally, the student will complete a three-year program to achieve all standards. Although these exit-level standards are designed…

  1. Standards for excellence

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A history of the development of standard units and regulations of measurement are discussed in this educational video. John Aston narrates the historical background, from colonial times to the present, of the need for measurement standardization and discusses the conception of the National Bureau of Standards (1901), of the United States Department of Commerce. Historical photography and film footage is included.

  2. Standards for excellence

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A history of the development of standard units and regulations of measurement are discussed in this educational video. John Aston narrates the historical background, from colonial times to the present, of the need for measurement standardization and discusses the conception of the National Bureau of Standards (1901), of the United States Department of Commerce. Historical photography and film footage is included.

  3. ALA Standards Manual.

    ERIC Educational Resources Information Center

    American Library Association, Chicago, IL. Committee on Standards.

    This American Library Association (ALA) policy statement and procedure manual is intended for use in the preparation of all standards issued by ALA and its component units to insure coordination of format and correlation of content of ALA standards. A brief discussion of the purpose of standards is offered, followed by definitions of four types of…

  4. New Coal Standards.

    ERIC Educational Resources Information Center

    Heritage, John

    1979-01-01

    Tighter federal air pollution control standards for new coal-burning electric power plants have been issued. Through use of air pollution control devices all types of coal will be useable under the new standards. Even stricter standards may be imposed where visibility may be affected in areas now enjoying very clean air. (RE)

  5. Emission Standards for Particulates

    ERIC Educational Resources Information Center

    Walsh, George W.

    1974-01-01

    Promulgation of standards of performance under Section 111 and national emission standards for hazardous pollutants under Section 112 of the Clean Air Act is the responsibility of the Emission Standards and Engineering Division of the Environmental Protection Agency. The problems encountered and the bases used are examined. (Author/BT)

  6. Standards for Administrators.

    ERIC Educational Resources Information Center

    Lashway, Larry

    1998-01-01

    This newsletter reviews five reports that address the implications of standards for administrators. These texts include "Designing and Implementing Standards-Based Accountability System" (Education Commission of the States), which describes some of the policy implications of standards-driven accountability; "Why Principals Fail: Are National…

  7. Radiological Control Technician: Standardized technician Qualification Standard

    SciTech Connect

    Not Available

    1992-10-01

    The Qualification Standard states and defines the knowledge and skill requirements necessary for successful completion of the Radiological Control Technician Training Program. The standard is divided into three phases: Phase I concerns RCT Academic training. There are 13 lessons associated with the core academics program and 19 lessons associated with the site academics program. The staff member should sign the appropriate blocks upon successful completion of the examination for that lesson or group of lessons. In addition, facility specific lesson plans may be added to meet the knowledge requirements in the Job Performance Measures (JPM) of the practical program. Phase II concerns RCT core/site practical (JPMs) training. There are thirteen generic tasks associated with the core practical program. Both the trainer/evaluator and student should sign the appropriate block upon successful completion of the JPM. In addition, facility specific tasks may be added or generic tasks deleted based on the results of the facility job evaluation. Phase III concerns the oral examination board successful completion of the oral examination board is documented by the signature of the chairperson of the board. Upon completion of all of the standardized technician qualification requirements, final qualification is verified by the student and the manager of the Radiological Control Department and acknowledged by signatures on the qualification standard. The completed Qualification Standard shall be maintained as an official training record.

  8. Effects of Electronic-State-Dependent Solute Polarizability: Application to Solute-Pump/Solvent-Probe Spectra.

    PubMed

    Sun, Xiang; Ladanyi, Branka M; Stratt, Richard M

    2015-07-23

    Experimental studies of solvation dynamics in liquids invariably ask how changing a solute from its electronic ground state to an electronically excited state affects a solution's dynamics. With traditional time-dependent-fluorescence experiments, that means looking for the dynamical consequences of the concomitant change in solute-solvent potential energy. But if one follows the shift in the dynamics through its effects on the macroscopic polarizability, as recent solute-pump/solvent-probe spectra do, there is another effect of the electronic excitation that should be considered: the jump in the solute's own polarizability. We examine the spectroscopic consequences of this solute polarizability change in the classic example of the solvation dye coumarin 153 dissolved in acetonitrile. After demonstrating that standard quantum chemical methods can be used to construct accurate multisite models for the polarizabilities of ground- and excited-state solvation dyes, we show via simulation that this polarizability change acts as a contrast agent, significantly enhancing the observable differences in optical-Kerr spectra between ground- and excited-state solutions. A comparison of our results with experimental solute-pump/solvent-probe spectra supports our interpretation and modeling of this spectroscopy. We predict, in particular, that solute-pump/solvent-probe spectra should be sensitive to changes in both the solvent dynamics near the solute and the electronic-state-dependence of the solute's own rotational dynamics.

  9. Prototype of a primary calibration system for measurement of radon activity concentration.

    PubMed

    Mostafa, M Y A; Vasyanovich, M; Zhukovsky, M

    2016-01-01

    To calibrate measurement devices for monitoring the activity concentration of (222)Rn in air, a prototype of a calibration facility is tested using a solid (226)Ra source and a high-purity germanium (HPGe) detector. An emanation box was mounted on the detector for online gamma measurements. Inside this box, a 32.8 kBq ±3% (226)Ra standard source was placed. An AlphaGUARD control radon monitor was connected to the emanation box with a pumping air system in an open flow mode as a reference monitor. The emanation coefficient of the source was controlled online by comparing the gamma activity of (214)Bi (Eγ=609.3 keV), progeny of (226)Ra, to that of the calibration source. A standard (137)Cs source, installed within the emanation box, was used as a reference for gamma spectroscopy using the HPGe detector, with a total systematic error of 4% and a random error less than 2%. The ratio between gamma measurements and AlphaGUARD was 0.94±0.4; which is within the 9% uncertainties of AlphaGUARD calibration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Permanent Turbidity-Standards

    PubMed Central

    Roessler, William G.; Brewer, Carl R.

    1967-01-01

    Permanent turbidity reference standards suitable for measurement of microbial suspensions were prepared by suspending finely divided titanium dioxide in aryl sulfonamide-formaldehyde or methylstyrene resins. Turbidities of these standards, adjusted to a useful range for microbiological and immunological studies, were compared with other reference standards in use today. Tube holders for a Coleman Photonephelometer and a Nepho-Colorimeter were modified to eliminate the water well and to allow use of optically standardized 10-, 16-, or 18-mm test tubes. The standards and the tube holders have been used satisfactorily for more than 12 years. Images Fig. 5 Fig. 6 PMID:6077410

  11. Standard Agent Framework 1

    SciTech Connect

    Goldsmith, Steven Y.

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4) Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.

  12. Isotopic delta values of molybdenum reference solutions

    NASA Astrophysics Data System (ADS)

    Wen, Hanjie; Carignan, Jean; Cloquet, Christophe; Zhu, Xiangkun; Zhang, Yuxu

    2010-05-01

    We report the isotopic composition of five molybdenum (Mo) standard reference solutions and four fractions from one of these solutions eluted through anion resin column relative to a sixth reference solution. Measurements were conducted using Isoprobe multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) at the Centre de Recherches Pétrographiques et Géochimiques (France) and Nu Plasma MC-ICP-MS at either the Ecole Normale Supérieure de Lyon (France) or the Laboratory of Isotope Geology in the Ministry of Land and Resources (China). The sample-standard bracketing method was employed to correct the mass bias for Mo isotopes during instrumental measurement. Except for the Merck Mo solution, all the Mo solutions were identical in isotopic composition within error. Although the JMC Mo solution has been used as the internal reference material by various groups, uncertainty may still occur with different lot numbers and availability might be limited. Here, we propose the NIST 3134 Mo solution as a new candidate for delta zero reference material, used for reporting Mo isotopic composition of natural samples. Isotopic compositions for four eluted fractions of the Sigma-Aldrich Mo solution range from 2.2 ‰ to -2.0 ‰ for δ97/95Mo relative to the NIST Mo standard. These values span the range of reported isotopic composition for natural terrestrial and experimental samples (approximately -0.5‰ to 1.6‰ for δ97/95Mo). We propose these eluted fractions to be used as secondary reference for Mo isotope measurements.

  13. IEEE standards worldwide

    SciTech Connect

    Hammons, T.J. )

    1995-01-01

    This article presents North American views on the development and use of internationally acceptable standards through strengthened ties with global standards organizations. The key ingredient to enhance the international reputation of IEEE standards is, without doubt, greater participation of members around the world. Standards that will really have force are those that are recognized as preeminent and that are sought after by organizations worldwide. it will be necessary to develop enhanced liaisons with standards organizations around the world, such as the IEC. These are some of the issues that will be addressed by panelists representing standards organizations and users from North America, United States, Canada, and Mexico. Also discussed is the importance of standards in the NAFTA and GATT agreements on trade.

  14. Static solutions of Einstein's equations with cylindrical symmetry

    NASA Astrophysics Data System (ADS)

    Trendafilova, C. S.; Fulling, S. A.

    2011-11-01

    In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well-known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the spacetime is curved. These solutions appear in the literature, but in different forms, corresponding to different definitions of the radial coordinate. Because all the vacuum solutions are singular on the axis, we attempt to match them to 'interior' solutions with nonvanishing energy density and pressure. In addition to the well-known 'cosmic string' solution joining on to the cone, we find some numerical solutions that join on to the other exterior solutions.

  15. NASA Technical Standards Program

    NASA Technical Reports Server (NTRS)

    Gill, Paul S.; Vaughan, William W.; Parker, Nelson C. (Technical Monitor)

    2002-01-01

    The NASA Technical Standards Program was officially established in 1997 as result of a directive issued by the Administrator. It is responsible for Agency wide technical standards development, adoption (endorsement), and conversion of Center-unique standards for Agency wide use. One major element of the Program is the review of NSA technical standards products and replacement with non-Government Voluntary Consensus Standards in accordance with directions issued by the Office of Management and Budget. As part of the Program's function, it developed a NASA Integrated Technical Standards Initiative that consists of and Agency wide full-text system, standards update notification system, and lessons learned-standards integration system. The Program maintains a 'one stop-shop' Website for technical standards ad related information on aerospace materials, etc. This paper provides information on the development, current status, and plans for the NAS Technical Standards Program along with metrics on the utility of the products provided to both users within the nasa.gov Domain and the Public Domain.

  16. NASA Technical Standards Program

    NASA Technical Reports Server (NTRS)

    Gill, Paul S.; Vaughan, WIlliam W.

    2003-01-01

    The NASA Technical Standards Program was officially established in 1997 as result of a directive issued by the Administrator. It is responsible for Agency wide technical standards development, adoption (endorsement), and conversion of Center-unique standards for Agency wide use. One major element of the Program is the review of NSA technical standards products and replacement with non-Government Voluntary Consensus Standards in accordance with directions issued by the Office of Management and Budget. As part of the Program s function, it developed a NASA Integrated Technical Standards Initiative that consists of and Agency wide full-text system, standards update notification system, and lessons learned - standards integration system. The Program maintains a "one stop-shop" Website for technical standards ad related information on aerospace materials, etc. This paper provides information on the development, current status, and plans for the NAS Technical Standards Program along with metrics on the utility of the products provided to both users within the nasa.gov Domain and the Public Domain.

  17. Solution deposition assembly

    SciTech Connect

    Roussillon, Yann; Scholz, Jeremy H; Shelton, Addison; Green, Geoff T; Utthachoo, Piyaphant

    2014-01-21

    Methods and devices are provided for improved deposition systems. In one embodiment of the present invention, a deposition system is provided for use with a solution and a substrate. The system comprises of a solution deposition apparatus; at least one heating chamber, at least one assembly for holding a solution over the substrate; and a substrate curling apparatus for curling at least one edge of the substrate to define a zone capable of containing a volume of the solution over the substrate. In another embodiment of the present invention, a deposition system for use with a substrate, the system comprising a solution deposition apparatus; at heating chamber; and at least assembly for holding solution over the substrate to allow for a depth of at least about 0.5 microns to 10 mm.

  18. An easy method for Ra-226 determination in river waters by liquid-scintillation counting

    NASA Astrophysics Data System (ADS)

    Moreno, H. P.; Vioque, I.; Manjón, G.; García-Tenorio, R.

    1999-01-01

    226Ra activity concentration in river water was determined using a low background liquid scintillation counter. Radium was extracted from the samples as Ra-BaSO4 precipitate which, afterwards, was dissolved with EDTA in ammonia medium. Solution was transferred into a low potassium glass vial and then mixed with a scintillation cocktail. Two different scintillation cocktails were selected for comparison. Efficiency, recovery yield and α/β separation were studied with both liquid scintillation cocktails. One single measurement, made one month after radium separation, allows to calculate the226Ra concentration as well as to assess the presence of alpha contamination of the sample. In the case of negligible interferences,224Ra concentrations can be subsequently evaluated in the same sample by the measurement made just after chemical separation of radium. This method has been applied for the determination of226Ra and224Ra activity concentrations in river water collected from different locations along the Odiel river estuary area (South-west of Spain). The presence of chemical industry, the wastes of which are released into the river, could be connected with radium activity concentration enhancements in the water.

  19. Time scale of hydrothermal water-rock reactions in Yellowstone National Park based on radium isotopes and radon

    NASA Astrophysics Data System (ADS)

    Clark, Jordan F.; Turekian, Karl K.

    1990-02-01

    We have measured 224Ra (3.4 d), 228Ra (5.7 yr), and 226Ra (1620 yr) and chloride in hot spring waters from the Norris-Mammoth Corridor, Yellowstone National Park. Two characteristic cold-water components mix with the primary hydrothermal water: one for the travertine-depositing waters related to the Mammoth Hot Springs and the other for the sinter-depositing Norris Geyser Basin springs. The Mammoth Hot Springs water is a mixture of the primary hydrothermal fluid with meteoric waters flowing through the Madison Limestone, as shown by the systematic decrease of the ( {228Ra}/{226Ra}) activity ratio proceeding northward. The Norris Geyser Basin springs are mixtures of primary hydrothermal water with different amounts of cold meteoric water with no modification of the primary hydrothermal ( {228Ra}/{226Ra}) activity ratio. Using a solution and recoil model for radium isotope supply to the primary hydrothermal water, a mean water-rock reaction time prior to expansion at 350°C and supply to the surface is 540 years assuming that 250 g of water are involved in the release of the radium from one gram of rock. The maximum reaction time allowed by our model is 1150 years.

  20. Mixed oxide solid solutions

    DOEpatents

    Magno, Scott; Wang, Ruiping; Derouane, Eric

    2003-01-01

    The present invention is a mixed oxide solid solution containing a tetravalent and a pentavalent cation that can be used as a support for a metal combustion catalyst. The invention is furthermore a combustion catalyst containing the mixed oxide solid solution and a method of making the mixed oxide solid solution. The tetravalent cation is zirconium(+4), hafnium(+4) or thorium(+4). In one embodiment, the pentavalent cation is tantalum(+5), niobium(+5) or bismuth(+5). Mixed oxide solid solutions of the present invention exhibit enhanced thermal stability, maintaining relatively high surface areas at high temperatures in the presence of water vapor.