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Sample records for bulk sample activation

  1. Determination of average activating thermal neutron flux in bulk samples

    International Nuclear Information System (INIS)

    Doczi, R.; Csikai, J.; Doczi, R.; Csikai, J.; Hassan, F. M.; Ali, M.A.

    2004-01-01

    A previous method used for the determination of the average neutron flux within bulky samples has been applied for the measurements of hydrogen contents of different samples. An analytical function is given for the description of the correlation between the activity of Dy foils and the hydrogen concentrations. Results obtained by the activation and the thermal neutron reflection methods are compared

  2. Neutron activation analysis of bulk samples from Chinese ancient porcelain to provenance research

    International Nuclear Information System (INIS)

    Jian Zhu; Wentao Hao; Jianming Zhen; Tongxiu Zhen; Glascock, M.D.

    2013-01-01

    Neutron activation analysis (NAA) is an important technique to determine the provenance of ancient ceramics. The most common technique used for preparing ancient samples for NAA is to grind them into a powder and then encapsulate them before neutron irradiation. Unfortunately, ceramic materials are typically very hard making it a challenge to grind them into a powder. In this study we utilize bulk porcelain samples cut from ancient shards. The bulk samples are irradiated by neutrons alongside samples that have been conventionally ground into a powder. The NAA for both the bulk samples and powders are compared and shown to provide equivalent information regarding their chemical composition. Also, the multivariate statistical have been employed to the analysis data for check the consistency. The findings suggest that NAA results are less dependent on the state of the porcelain sample, and thus bulk samples cut from shards may be used to effectively determine their provenance. (author)

  3. Bulk - Samples gamma-rays activation analysis (PGNAA) with Isotopic Neutron Sources

    International Nuclear Information System (INIS)

    HASSAN, A.M.

    2009-01-01

    An overview is given on research towards the Prompt Gamma-ray Neutron Activation Analysis (PGNAA) of bulk-samples. Some aspects in bulk-sample PGNAA are discussed, where irradiation by isotopic neutron sources is used mostly for in-situ or on-line analysis. The research was carried out in a comparative and/or qualitative way or by using a prior knowledge about the sample material. Sometimes we need to use the assumption that the mass fractions of all determined elements add up to 1. The sensitivity curves are also used for some elements in such complex samples, just to estimate the exact percentage concentration values. The uses of 252 Cf, 241 Arn/Be and 239 Pu/Be isotopic neutron sources for elemental investigation of: hematite, ilmenite, coal, petroleum, edible oils, phosphates and pollutant lake water samples have been mentioned.

  4. Prompt Gamma Activation Analysis (PGAA): Technique of choice for nondestructive bulk analysis of returned comet samples

    International Nuclear Information System (INIS)

    Lindstrom, D.J.; Lindstrom, R.M.

    1989-01-01

    Prompt gamma activation analysis (PGAA) is a well-developed analytical technique. The technique involves irradiation of samples in an external neutron beam from a nuclear reactor, with simultaneous counting of gamma rays produced in the sample by neutron capture. Capture of neutrons leads to excited nuclei which decay immediately with the emission of energetic gamma rays to the ground state. PGAA has several advantages over other techniques for the analysis of cometary materials: (1) It is nondestructive; (2) It can be used to determine abundances of a wide variety of elements, including most major and minor elements (Na, Mg, Al, Si, P, K, Ca, Ti, Cr, Mn, Fe, Co, Ni), volatiles (H, C, N, F, Cl, S), and some trace elements (those with high neutron capture cross sections, including B, Cd, Nd, Sm, and Gd); and (3) It is a true bulk analysis technique. Recent developments should improve the technique's sensitivity and accuracy considerably

  5. Studies on thermal neutron perturbation factor needed for bulk sample activation analysis

    CERN Document Server

    Csikai, J; Sanami, T; Michikawa, T

    2002-01-01

    The spatial distribution of thermal neutrons produced by an Am-Be source in a graphite pile was measured via the activation foil method. The results obtained agree well with calculated data using the MCNP-4B code. A previous method used for the determination of the average neutron flux within thin absorbing samples has been improved and extended for a graphite moderator. A procedure developed for the determination of the flux perturbation factor renders the thermal neutron activation analysis of bulky samples of unknown composition possible both in hydrogenous and graphite moderators.

  6. Calculation of thermal neutron self-shielding correction factors for aqueous bulk sample prompt gamma neutron activation analysis using the MCNP code

    International Nuclear Information System (INIS)

    Nasrabadi, M.N.; Jalali, M.; Mohammadi, A.

    2007-01-01

    In this work thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing materials is studied using bulk sample prompt gamma neutron activation analysis (BSPGNAA) with the MCNP code. The code was used to perform three dimensional simulations of a neutron source, neutron detector and sample of various material compositions. The MCNP model was validated against experimental measurements of the neutron flux performed using a BF 3 detector. Simulations were performed to predict thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing solutes. In practice, the MCNP calculations are combined with experimental measurements of the relative thermal neutron flux over the sample's surface, with respect to a reference water sample, to derive the thermal neutron self-shielding within the sample. The proposed methodology can be used for the determination of the elemental concentration of unknown aqueous samples by BSPGNAA where knowledge of the average thermal neutron flux within the sample volume is required

  7. Sample dependent response of a LaCl{sub 3}:Ce detector in prompt gamma neutron activation analysis of bulk hydrocarbon samples

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Khateeb-ur-Rehman,; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2013-08-11

    The response of a LaCl{sub 3}:Ce detector has been found to depend upon the hydrogen content of bulk samples in prompt gamma analysis using 14 MeV neutron inelastic scattering. The moderation of 14 MeV neutrons from hydrogen in the bulk sample produces thermal neutrons around the sample which ultimately excite chlorine capture gamma rays in the LaCl{sub 3}:Ce detector material. Interference of 6.11 MeV chlorine gamma rays from the detector itself with 6.13 MeV oxygen gamma rays from the bulk samples makes the intensity of the 6.13 MeV oxygen gamma ray peak relatively insensitive to variations in oxygen concentration. The strong dependence of the 1.95 MeV doublet chlorine gamma ray yield on hydrogen content of the bulk samples confirms fast neutron moderation from hydrogen in the bulk samples as a major source of production of thermal neutrons and chlorine gamma rays in the LaCl{sub 3}:Ce detector material. Despite their poor oxygen detection capabilities, these detectors have nonetheless excellent detection capabilities for hydrogen and carbon in benzene, butyl alcohol, propanol, propanic acid, and formic acid bulk samples using 14 MeV neutron inelastic scattering.

  8. Effect of sample moisture and bulk density on performance of the 241Am-Be source based prompt gamma rays neutron activation analysis setup. A Monte Carlo study

    International Nuclear Information System (INIS)

    Almisned, Ghada

    2010-01-01

    Monte Carlo simulations were carried out using the dependence of gamma ray yield on the bulk density and moisture content for five different lengths of Portland cement samples in a thermal neutron capture based Prompt Gamma ray Neutron Activation Analysis (PGNAA) setup for source inside moderator geometry using an 241 Am-Be neutron source. In this study, yields of 1.94 and 6.42 MeV prompt gamma rays from calcium in the five Portland cement samples were calculated as a function of sample bulk density and moisture content. The study showed a strong dependence of the 1.94 and 6.42 MeV gamma ray yield upon the sample bulk density but a weaker dependence upon sample moisture content. For an order of magnitude increase in the sample bulk density, an order of magnitude increase in the gamma rays yield was observed, i.e., a one-to-one correspondence. In case of gamma ray yield dependence upon sample moisture content, an order of magnitude increase in the moisture content of the sample resulted in about 16-17% increase in the yield of 1.94 and 6.42 MeV gamma rays from calcium. (author)

  9. Monte Carlo calculations and neutron spectrometry in quantitative prompt gamma neutron activation analysis (PGNAA) of bulk samples using an isotopic neutron source

    International Nuclear Information System (INIS)

    Spyrou, N.M.; Awotwi-Pratt, J.B.; Williams, A.M.

    2004-01-01

    An activation analysis facility based on an isotopic neutron source (185 GBq 241 Am/Be) which can perform both prompt and cyclic activation analysis on bulk samples, has been used for more than 20 years in many applications including 'in vivo' activation analysis and the determination of the composition of bio-environmental samples, such as, landfill waste and coal. Although the comparator method is often employed, because of the variety in shape, size and elemental composition of these bulk samples, it is often difficult and time consuming to construct appropriate comparator samples for reference. One of the obvious problems is the distribution and energy of the neutron flux in these bulk and comparator samples. In recent years, it was attempted to adopt the absolute method based on a monostandard and to make calculations using a Monte Carlo code (MCNP4C2) to explore this further. In particular, a model of the irradiation facility has been made using the MCNP4C2 code in order to investigate the factors contributing to the quantitative determination of the elemental concentrations through prompt gamma neutron activation analysis (PGNAA) and most importantly, to estimate how the neutron energy spectrum and neutron dose vary with penetration depth into the sample. This simulation is compared against the scattered and transmitted neutron energy spectra that are experimentally and empirically determined using a portable neutron spectrometry system. (author)

  10. Soft magnetic properties of bulk amorphous Co-based samples

    International Nuclear Information System (INIS)

    Fuezer, J.; Bednarcik, J.; Kollar, P.

    2006-01-01

    Ball milling of melt-spun ribbons and subsequent compaction of the resulting powders in the supercooled liquid region were used to prepare disc shaped bulk amorphous Co-based samples. The several bulk samples have been prepared by hot compaction with subsequent heat treatment (500 deg C - 575 deg C). The influence of the consolidation temperature and follow-up heat treatment on the magnetic properties of bulk samples was investigated. The final heat treatment leads to decrease of the coercivity to the value between the 7.5 to 9 A/m (Authors)

  11. Bulk sample self-attenuation correction by transmission measurement

    International Nuclear Information System (INIS)

    Parker, J.L.; Reilly, T.D.

    1976-01-01

    Various methods used in either finding or avoiding the attenuation correction in the passive γ-ray assay of bulk samples are reviewed. Detailed consideration is given to the transmission method, which involves experimental determination of the sample linear attenuation coefficient by measuring the transmission through the sample of a beam of gamma rays from an external source. The method was applied to box- and cylindrically-shaped samples

  12. Standard practice for bulk sampling of liquid uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice covers methods for withdrawing representative samples of liquid uranium hexafluoride (UF6) from bulk quantities of the material. Such samples are used for determining compliance with the applicable commercial specification, for example Specification C787 and Specification C996. 1.2 It is assumed that the bulk liquid UF6 being sampled comprises a single quality and quantity of material. This practice does not address any special additional arrangements that might be required for taking proportional or composite samples, or when the sampled bulk material is being added to UF6 residues already in a container (“heels recycle”). 1.3 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the parties. 1.4 The scope of this practice does not include provisions for preventing criticality incidents. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of th...

  13. Gamma self-shielding correction factors calculation for aqueous bulk sample analysis by PGNAA technique

    International Nuclear Information System (INIS)

    Nasrabadi, M.N.; Mohammadi, A.; Jalali, M.

    2009-01-01

    In this paper bulk sample prompt gamma neutron activation analysis (BSPGNAA) was applied to aqueous sample analysis using a relative method. For elemental analysis of an unknown bulk sample, gamma self-shielding coefficient was required. Gamma self-shielding coefficient of unknown samples was estimated by an experimental method and also by MCNP code calculation. The proposed methodology can be used for the determination of the elemental concentration of unknown aqueous samples by BSPGNAA where knowledge of the gamma self-shielding within the sample volume is required.

  14. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z.; Gondal, M.A.; Rehman, Khateeb-ur [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Raashid, M.; Dastageer, M.A. [Department of Physics and King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2013-11-21

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53–3.68, 4.51, 5.27–5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples.

  15. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Al-Matouq, Faris A.; Khiari, F.Z.; Gondal, M.A.; Rehman, Khateeb-ur; Isab, A.A.; Raashid, M.; Dastageer, M.A.

    2013-01-01

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53–3.68, 4.51, 5.27–5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples

  16. 350 keV accelerator based PGNAA setup to detect nitrogen in bulk samples

    Science.gov (United States)

    Naqvi, A. A.; Al-Matouq, Faris A.; Khiari, F. Z.; Gondal, M. A.; Rehman, Khateeb-ur; Isab, A. A.; Raashid, M.; Dastageer, M. A.

    2013-11-01

    Nitrogen concentration was measured in explosive and narcotics proxy material, e.g. anthranilic acid, caffeine, melamine, and urea samples, bulk samples through thermal neutron capture reaction using 350 keV accelerator based prompt gamma ray neutron activation (PGNAA) setup. Intensity of 2.52, 3.53-3.68, 4.51, 5.27-5.30 and 10.38 MeV prompt gamma rays of nitrogen from the bulk samples was measured using a cylindrical 100 mm×100 mm (diameter×height ) BGO detector. Inspite of interference of nitrogen gamma rays from bulk samples with capture prompt gamma rays from BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays has been obtained. This is an indication of the excellent performance of the PGNAA setup for detection of nitrogen in bulk samples.

  17. Should bulk cloudwater or fogwater samples obey Henry's law?

    Science.gov (United States)

    Pandis, Spyros N.; Seinfeld, John H.

    1991-06-01

    Mixing of droplets with different pH that are individually in Henry's law equilibrium with the surrounding atmosphere always results in a bulk mixture that is supersaturated with weak acids like S(IV) and HCOOH, and bases like NH3 with respect to the original atmosphere. High supersaturations result only when the pH of the bulk droplet mixture exceeds the pKa of the species, in which pH range large pH differences among droplets of different sizes lead to large deviations from Henry's law for the bulk mixture. The deviation is shown to depend on the ratio of the arithmetic mean to the harmonic mean of the hydrogen ion concentrations of the droplets with the liquid water content used as weighting factor in the calculation of the means. The theory developed can explain observed discrepancies from Henry's law in atmospheric samples and also other observed phenomena like the reported increase of pH values of bulk aqueous samples during storage.

  18. Positron annihilation lifetime spectroscopy of ZnO bulk samples

    International Nuclear Information System (INIS)

    Zubiaga, A.; Plazaola, F.; Garcia, J. A.; Tuomisto, F.; Munoz-Sanjose, V.; Tena-Zaera, R.

    2007-01-01

    In order to gain a further insight into the knowledge of point defects of ZnO, positron annihilation lifetime spectroscopy was performed on bulk samples annealed under different atmospheres. The samples were characterized at temperatures ranging from 10 to 500 K. Due to difficulties in the conventional fitting of the lifetime spectra caused by the low intensity of the defect signals, we have used an alternative method as a solution to overcome these difficulties and resolve all the lifetime components present in the spectra. Two different vacancy-type defects are identified in the samples: Zn vacancy complexes (V Zn -X) and vacancy clusters consisting of up to five missing Zn-O pairs. In addition to the vacancies, we observe negative-ion-type defects, which are tentatively attributed to intrinsic defects in the Zn sublattice. The effect of the annealing on the observed defects is discussed. The concentrations of the V Zn -X complexes and negative-ion-type defects are in the 0.2-2 ppm range, while the cluster concentrations are 1-2 orders of magnitude lower

  19. Neutron moderation in a bulk sample and its effects on PGNAA setup geometry

    International Nuclear Information System (INIS)

    Al-Jarallah, M.I.; Naqvi, A.A.; Fazal-ur-Rehman,; Maselehuddin, M.; Abu-Jarad, F.; Raashid, M.

    2003-01-01

    In a prompt gamma ray neutron activation analysis (PGNAA) setup, the neutron moderation in the bulk sample also plays a key role. This can even dominate the thermalization effects of the external moderator in some cases. In order to study the neutron moderation effect in the bulk sample, moderators with two different sizes of the sample were tested at the King Fahd University of Petroleum and Minerals (KFUPM) PGNAA facility. In these tests, the thermal neutron relative intensity and prompt gamma ray yield from the two moderators were measured using nuclear track detectors (NTDs) and NaI detector, respectively. As predicted by Monte Carlo simulations, the measured intensity of thermal neutron inside the large sample cavity due to the external moderator was smaller than that from the smaller sample cavity. Due to its larger size, additional thermalization of neutrons will take place in the larger sample. In spite of smaller thermal neutron yield from the external moderator at the large sample location, higher yield of the prompt gamma ray was observed as compared to that from the smaller sample. This confirms the significance of neutron moderation effects in the bulk sample and can thereby affect the PGNAA geometry size. This allows larger samples in conjunction with smaller moderators in the PGNAA setup

  20. Neutron moderation in a bulk sample and its effects on PGNAA setup geometry

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jarallah, M.I. E-mail: mibrahim@kfupm.edu.sa; Naqvi, A.A.; Fazal-ur-Rehman,; Maselehuddin, M.; Abu-Jarad, F.; Raashid, M

    2003-06-01

    In a prompt gamma ray neutron activation analysis (PGNAA) setup, the neutron moderation in the bulk sample also plays a key role. This can even dominate the thermalization effects of the external moderator in some cases. In order to study the neutron moderation effect in the bulk sample, moderators with two different sizes of the sample were tested at the King Fahd University of Petroleum and Minerals (KFUPM) PGNAA facility. In these tests, the thermal neutron relative intensity and prompt gamma ray yield from the two moderators were measured using nuclear track detectors (NTDs) and NaI detector, respectively. As predicted by Monte Carlo simulations, the measured intensity of thermal neutron inside the large sample cavity due to the external moderator was smaller than that from the smaller sample cavity. Due to its larger size, additional thermalization of neutrons will take place in the larger sample. In spite of smaller thermal neutron yield from the external moderator at the large sample location, higher yield of the prompt gamma ray was observed as compared to that from the smaller sample. This confirms the significance of neutron moderation effects in the bulk sample and can thereby affect the PGNAA geometry size. This allows larger samples in conjunction with smaller moderators in the PGNAA setup.

  1. High mechanical Q-factor measurements on silicon bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Nawrodt, R; Zimmer, A; Koettig, T; Schwarz, C; Heinert, D; Hudl, M; Neubert, R; Thuerk, M; Nietzsche, S; Vodel, W; Seidel, P [Friedrich-Schiller-Universitaet, Institut fuer Festkoerperphysik, Helmholtzweg 5, D-07743 Jena (Germany); Tuennermann, A [Friedrich-Schiller-Universitaet, Institut fuer Angewandte Physik, Max-Wien-Platz 1, D-07743 Jena (Germany)], E-mail: ronny.nawrodt@uni-jena.de

    2008-07-15

    Future gravitational wave detectors will be limited by different kinds of noise. Thermal noise from the coatings and the substrate material will be a serious noise contribution within the detection band of these detectors. Cooling and the use of a high mechanical Q-factor material as a substrate material will reduce the thermal noise contribution from the substrates. Silicon is one of the most interesting materials for a third generation cryogenic detector. Due to the fact that the coefficient of thermal expansion vanishes at 18 and 125 K the thermoelastic contribution to the thermal noise will disappear. We present a systematic analysis of the mechanical Q-factor at low temperatures between 5 and 300 K on bulk silicon (100) samples which are boron doped. The thickness of the cylindrical samples is varied between 6, 12, 24, and 75mm with a constant diameter of 3 inches. For the 75mm substrate a comparison between the (100) and the (111) orientation is presented. In order to obtain the mechanical Q-factor a ring-down measurement is performed. Thus, the substrate is excited to resonant vibrations by means of an electrostatic driving plate and the subsequent ring-down is recorded using a Michelson-like interferometer. The substrate itself is suspended as a pendulum by means of a tungsten wire loop. All measurements are carried out in a special cryostat which provides a temperature stability of better than 0.1K between 5 and 300K during the experiment. The influence of the suspension on the measurements is experimentally investigated and discussed. At 5.8K a highest Q-factor of 4.5 x 10{sup 8} was achieved for the 14.9 kHz mode of a silicon (100) substrate with a diameter of 3 inches and a thickness of 12 mm.

  2. Molecular detection of Coxiella burnetii in goat bulk milk samples in ...

    African Journals Online (AJOL)

    . The objective of this study was to determine the prevalence rate of C. burnetii in bulk milk samples from dairy goat herds in Fars, Ghom, Kerman, Khuzestan and Yazd provinces, Iran. In this study, 296 bulk milk samples from 89 dairy goat ...

  3. Sample sizes to control error estimates in determining soil bulk density in California forest soils

    Science.gov (United States)

    Youzhi Han; Jianwei Zhang; Kim G. Mattson; Weidong Zhang; Thomas A. Weber

    2016-01-01

    Characterizing forest soil properties with high variability is challenging, sometimes requiring large numbers of soil samples. Soil bulk density is a standard variable needed along with element concentrations to calculate nutrient pools. This study aimed to determine the optimal sample size, the number of observation (n), for predicting the soil bulk density with a...

  4. ENVIRONMENTAL SAMPLING USING LOCATION SPECIFIC AIR MONITORING IN BULK HANDLING FACILITIES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, L.; Hanks, D.; Degange, J.; Brant, H.; Hall, G.; Cable-Dunlap, P.; Anderson, B.

    2011-06-07

    Since the introduction of safeguards strengthening measures approved by the International Atomic Energy Agency (IAEA) Board of Governors (1992-1997), international nuclear safeguards inspectors have been able to utilize environmental sampling (ES) (e.g. deposited particulates, air, water, vegetation, sediments, soil and biota) in their safeguarding approaches at bulk uranium/plutonium handling facilities. Enhancements of environmental sampling techniques used by the IAEA in drawing conclusions concerning the absence of undeclared nuclear materials or activities will soon be able to take advantage of a recent step change improvement in the gathering and analysis of air samples at these facilities. Location specific air monitoring feasibility tests have been performed with excellent results in determining attribute and isotopic composition of chemical elements present in an actual test-bed sample. Isotopic analysis of collected particles from an Aerosol Contaminant Extractor (ACE) collection, was performed with the standard bulk sampling protocol used throughout the IAEA network of analytical laboratories (NWAL). The results yielded bulk isotopic values expected for the operations. Advanced designs of air monitoring instruments such as the ACE may be used in gas centrifuge enrichment plants (GCEP) to detect the production of highly enriched uranium (HEU) or enrichments not declared by a State. Researchers at Savannah River National Laboratory in collaboration with Oak Ridge National Laboratory are developing the next generation of ES equipment for air grab and constant samples that could become an important addition to the international nuclear safeguards inspector's toolkit. Location specific air monitoring to be used to establish a baseline environmental signature of a particular facility employed for comparison of consistencies in declared operations will be described in this paper. Implementation of air monitoring will be contrasted against the use of smear

  5. Determination of uranium in samples containing bulk aluminium

    International Nuclear Information System (INIS)

    Das, S.K.; Kannan, R.; Dhami, P.S.; Tripathi, S.C.; Gandhi, P.M.

    2015-01-01

    The determination of uranium is of great importance in PUREX process and need to be analyzed at different concentration ranges depending on the stage of reprocessing. Various techniques like volumetry, spectrophotometry, ICP-OES, fluorimetry, mass spectrometry etc. are used for the measurement of uranium in these samples. Fast and sensitive methods suitable for low level detection of uranium are desirable to cater the process needs. Microgram quantities of uranium are analyzed by spectrophotometric method using 2-(5- bromo-2-pyridylazo-5-diethylaminophenol) (Br-PADAP) as the complexing agent. But, the presence of some of the metal ions viz. Al, Pu, Zr etc. interferes in its analysis. Therefore, separation of uranium from such interfering metal ions is required prior to its analysis. This paper describes the analysis of uranium in samples containing aluminium as major matrix

  6. Effect of density increase on self-absorption property of bulk samples

    International Nuclear Information System (INIS)

    Dao Anh Minh; Tran Duc Thiep

    1990-01-01

    Asymptotic behaviour due to self-absorption of photon attenuation function in terms of material density for bulk samples has been considered. Some practical applications have also been presented. (author). 9 refs., 4 figs., 2 tabs

  7. Utilization of neutrons in nuclear data measurements and bulk sample analysis

    International Nuclear Information System (INIS)

    Jonah, S. A.

    1995-01-01

    Experimental investigations were carried out with neutrons in the fields of neutron data measurements and bulk sample analysis based on the interactions of neutron interactions required in the investigations together with some salient features of the sources employed are enumerated. Excitation cross section curves and isomeric cross section ratio of 58 Ni(n,p) 58 Co m , g reaction over the neutron energy range of between 5 and 15 MeV were determined using the activation analysis technique in combination with high-resolution gamma spectroscopy. Characteristics of the incident neutrons produced via the D-T reaction of a neutron generator and D-D reaction of a cyclotron were determined experimentally to account for the contributing effects of background neutrons especially in the 5-13 MeV neutron energy range where existing data are scanty and rather discrepant. The measured data agree well with calculated data using nuclear models but deviate significantly from the recommended data based on existing literature data. The measured δ act and δ m /δ g data made it possible to determine the cross section curve for 58 Ni(n,p) 58 Co m reaction. Furthermore the flux density distributions of thermal and primary fast neutrons in different configurations of bulk samples consisting of water, graphite and coal together with the attenuation characteristics were determined by the activation analysis and pulse height response spectrometry techniques. From the results obtained, an experimental geometry has been proposed for on-line elemental analysis of coal and other minerals. Similarly the total hydrogen content and 0+C/H atomic ratio in household and motor oils as well as crude oil samples of different origins were measured by an improved experimental arrangement based on the thermal neutron reflection technique. A detection limit of 0.12 w % was obtained for hydrogen indicating the possible adaptation of this technique for quality control of petroleum products

  8. High resolution gamma-ray spectroscopy applied to bulk sample analysis

    International Nuclear Information System (INIS)

    Kosanke, K.L.; Koch, C.D.; Wilson, R.D.

    1980-01-01

    A high resolution Ge(Li) gamma-ray spectrometer has been installed and made operational for use in routine bulk sample analysis by the Bendix Field Engineering Corporation (BFEC) geochemical analysis department. The Ge(Li) spectrometer provides bulk sample analyses for potassium, uranium, and thorium that are superior to those obtained by the BFEC sodium iodide spectrometer. The near term analysis scheme permits a direct assay for uranium that corrects for bulk sample self-absorption effects and is independent of the uranium/radium disequilibrium condition of the sample. A more complete analysis scheme has been developed that fully utilizes the gamma-ray data provided by the Ge(Li) spectrometer and that more properly accounts for the sample self-absorption effect. This new analysis scheme should be implemented on the BFEC Ge(Li) spectrometer at the earliest date

  9. Should bulk cloudwater or fogwater samples obey Henry's law

    Energy Technology Data Exchange (ETDEWEB)

    Pandis, S.N.; Seinfeld, J.H. (Department of Chemical Engineering and Environmental Quality Laboratory, California Institute of Technology, Pasadena, CA (USA))

    1991-06-20

    In this work we prove that mixing of droplets with different {ital p}H that are individually in Henry's law equilibrium with the surrounding atmosphere always results in a bulk mixture that is supersaturated with weak acids like S(IV) and HCOOH and bases like NH{sub 3} with respect to the original atmosphere. The degree of supersaturation of the bulk liquid water sample for a particular species depends on its dissociation constant, on the initial {ital p}H of the bulk droplet mixture, and on the distribution of the {ital p}H and of the liquid water over the droplet spectrum. High supersaturations result only when the {ital p}H of the bulk droplet mixture exceeds the {ital p}K{sub {ital a}} of the species, in which {ital p}H range large {ital p}H differences among droplets of different sizes lead to large deviations from Henry's law for the bulk mixture. The deviation is shown to depend on the ratio of the arithmetic mean to the harmonic mean of the hydrogen ion concentrations of the droplets with the liquid water content used was weighting factor in the calculation of the means. The theory developed can explain observed discrepancies from Henry's law in atmospheric samples and also other observed phenomena like the reported increase of {ital p}H values of bulk aqueous samples during storage. {copyright} American Geophysical Union 1991

  10. Use of thermal neutron reflection method for chemical analysis of bulk samples

    International Nuclear Information System (INIS)

    Papp, A.; Csikai, J.

    2014-01-01

    Microscopic, σ β , and macroscopic, Σ β , reflection cross-sections of thermal neutrons averaged over bulk samples as a function of thickness (z) are given. The σ β values are additive even for bulk samples in the z=0.5–8 cm interval and so the σ βmol (z) function could be given for hydrogenous substances, including some illicit drugs, explosives and hiding materials of ∼1000 cm 3 dimensions. The calculated excess counts agree with the measured R(z) values. For the identification of concealed objects and chemical analysis of bulky samples, different neutron methods need to be used simultaneously. - Highlights: • Check the proposed analytical expression for the description of the flux. • Determination of the reflection cross-sections averaged over bulk samples. • Data rendered to estimate the excess counts for various materials

  11. Use of thermal neutron reflection method for chemical analysis of bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Papp, A., E-mail: papppa@atomki.hu [Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), 4001 Debrecen, Pf. 51 (Hungary); Csikai, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), 4001 Debrecen, Pf. 51 (Hungary); Institute of Experimental Physics, University Debrecen (IEP), 4010 Debrecen-10, Pf. 105 (Hungary)

    2014-09-11

    Microscopic, σ{sub β}, and macroscopic, Σ{sub β}, reflection cross-sections of thermal neutrons averaged over bulk samples as a function of thickness (z) are given. The σ{sub β} values are additive even for bulk samples in the z=0.5–8 cm interval and so the σ{sub βmol}(z) function could be given for hydrogenous substances, including some illicit drugs, explosives and hiding materials of ∼1000 cm{sup 3} dimensions. The calculated excess counts agree with the measured R(z) values. For the identification of concealed objects and chemical analysis of bulky samples, different neutron methods need to be used simultaneously. - Highlights: • Check the proposed analytical expression for the description of the flux. • Determination of the reflection cross-sections averaged over bulk samples. • Data rendered to estimate the excess counts for various materials.

  12. Progress in quantitative X-ray microanalysis of frozen-hydrated bulk biological samples

    International Nuclear Information System (INIS)

    Marshall, A.T.

    1988-01-01

    The analysis of bulk frozen-hydrated biological samples has developed now to a level where practical application of the technique is possible. Provided the sample is carefully coated with a conductive metal, the development of a space charge capable of causing a significant distortion of the electron diffusion volume does not seem to occur, and analytical resolution can be conveniently held to approximately 2 micron (both depth and lateral resolution). Two valid quantitative methods are available, and two methods of determining dry weight fractions are also available. An area where further research could lead to improvement in analysis of frozen-hydrated bulk samples is in the investigation of fracturing methods. If fracture planes that were flat and reproducible could be easily obtained, some of the difficulties of analysing frozen-hydrated bulk samples would be considerably reduced

  13. The complex ac susceptibility of superconducting Y-Ba-CuO thin film and bulk samples

    International Nuclear Information System (INIS)

    Lobotka, P.; Goemoery, F.

    1988-01-01

    Complex ac susceptibility measurements as function of temperature on Y-Ba-CuO superconductors are reported. A strong dependence of the susceptibility curves on the ac field magnitude and little influence of the superimposed dc field are observed on both, thin film and bulk samples. The susceptibilities of these materials are frequency independent in the range 30 to 7200 Hz what demonstrates the negligible role of eddy currents. A second peak in the imaginary part of susceptibility is observed in the bulk sample at higher levels of ac field. This implies the existence of another component in the sample with higher T c and lower losses. (author)

  14. Efficiency and attenuation correction factors determination in gamma spectrometric assay of bulk samples using self radiation

    International Nuclear Information System (INIS)

    Haddad, Kh.

    2009-02-01

    Gamma spectrometry forms the most important and capable tool for measuring radioactive materials. Determination of the efficiency and attenuation correction factors is the most tedious problem in the gamma spectrometric assay of bulk samples. A new experimental and easy method for these correction factors determination using self radiation was proposed in this work. An experimental study of the correlation between self attenuation correction factor and sample thickness and its practical application was also introduced. The work was performed on NORM and uranyl nitrate bulk sample. The results of proposed methods agreed with those of traditional ones.(author)

  15. Highly oriented Bi-system bulk sample prepared by a decomposition-crystallization process

    International Nuclear Information System (INIS)

    Xi Zhengping; Zhou Lian; Ji Chunlin

    1992-01-01

    A decomposition-crystallization method, preparing highly oriented Bi-system bulk sample is reported. The effects of processing parameter, decomposition temperature, cooling rate and post-treatment condition on texture and superconductivity are investigated. The method has successfully prepared highly textured Bi-system bulk samples. High temperature annealing does not destroy the growing texture, but the cooling rate has some effect on texture and superconductivity. Annealing in N 2 /O 2 atmosphere can improve superconductivity of the textured sample. The study on the superconductivity of the Bi(Pb)-Sr-Ca-Cu-O bulk material has been reported in numerous papers. The research on J c concentrates on the tape containing the 2223 phase, with very few studies on the J c of bulk sample. The reason for the lack of studies is that the change of superconducting phases at high temperatures has not been known. The authors have reported that the 2212 phase incongruently melted at about 875 degrees C and proceeded to orient the c-axis perpendicular to the surface in the process of crystallization of the 2212 phase. Based on that result, a decomposition-crystallization method was proposed to prepare highly oriented Bi-system bulk sample. In this paper, the process is described in detail and the effects of processing parameters on texture and superconductivity are reported

  16. Nitrogen Detection in Bulk Samples Using a D-D Reaction-Based Portable Neutron Generator

    Directory of Open Access Journals (Sweden)

    A. A. Naqvi

    2013-01-01

    Full Text Available Nitrogen concentration was measured via 2.52 MeV nitrogen gamma ray from melamine, caffeine, urea, and disperse orange bulk samples using a newly designed D-D portable neutron generator-based prompt gamma ray setup. Inspite of low flux of thermal neutrons produced by D-D reaction-based portable neutron generator and interference of 2.52 MeV gamma rays from nitrogen in bulk samples with 2.50 MeV gamma ray from bismuth in BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays indicates satisfactory performance of the setup for detection of nitrogen in bulk samples.

  17. Pursuit of improvement in uranium bulk analysis at the clear facility for safeguards environmental samples

    International Nuclear Information System (INIS)

    Sakurai, S.; Takahashi, M.; Sakakibara, T.; Magara, M.; Kurosawa, S.; Esaka, F.; Takai, K.; Watanabe, K.; Usuda, S.; Adachi, T.

    2002-01-01

    Full text: In order to contribute to the IAEA strengthened safeguards system, a project started in Japan Atomic Energy Research Institute (JAERI) in 1998. Consequently, a clean room facility called as CLEAR, the Clean Laboratory for Environmental Analysis and Research, was constructed in June 2001 at JAERI Tokai and the analytical techniques of ultra-trace nuclear materials in environmental samples are being developed. As for the bulk analysis, performance of inductively-coupled plasma mass spectrometry (ICP-MS) was mainly examined because sample preparation for ICP-MS is simpler than that for thermal ionization mass spectrometry (TIMS). Interference of polyatomic ion (such as PtAr + ) and coexisting element (such as Na) on the uranium ions, as well as mass bias caused by ICP-MS operating conditions, has been investigated for precise measurement on uranium isotope ratio. The authors have also studied on the uranium blanks during sample treatment process. The blank value below 10 pg uranium per sample treatment was obtained: dominant origins were elution from Teflon vessel surface in acid heating process of the sample to dry up. The work is in progress to minimize the blank. Compared with the process blank and the minimum uranium amount for isotope ratio measurement by ICP-MS (ca. 10 pg for natural uranium), the swipe cotton (Texwipe-304) which is currently used for IAEA Environmental Sampling includes much more amount of natural uranium in several nano-grams. If the amount of uranium collected on Texwipe-304 is small, sensitive and reliable measurement on isotope ratio will be impossible by bulk analysis. The authors are seeking alternative swipe materials with less amount of uranium. Recently, one of the authors devised an effective technique for recovery of uranium-containing particles from Texwipe-304. The technique, named as Vacuum Suction Method, uses a combination of polycarbonate membrane filters and a macro-pipette tip, which is connected to a vacuum pump

  18. Combination closed-cycle refrigerator/liquid-He4 cryostat for e- damage of bulk samples

    International Nuclear Information System (INIS)

    Johnson, E.C.

    1987-01-01

    A closed-cycle refrigerator/cryostat system for use in ultrasonic studies of electron irradiation damaged bulk specimens is described. The closed-cycle refrigerator provides a convenient means for long-term (several days) sample irradiation at low temperatures. A neon filled ''thermal diode'' is employed to permit efficient cooling, via liquid helium, of the sample below the base temperature of the refrigerator

  19. Analyses and Comparison of Bulk and Coil Surface Samples from the DWPF Slurry Mix Evaporator

    International Nuclear Information System (INIS)

    Hay, M.; Nash, C.; Stone, M.

    2012-01-01

    Sludge samples from the DWPF Slurry Mix Evaporator (SME) heating coil frame and coil surface were characterized to identify differences that might help identify heat transfer fouling materials. The SME steam coils have seen increased fouling leading to lower boil-up rates. Samples of the sludge were taken from the coil frame somewhat distant from the coil (bulk tank material) and from the coil surface (coil surface sample). The results of the analysis indicate the composition of the two SME samples are very similar with the exception that the coil surface sample shows ∼5-10X higher mercury concentration than the bulk tank sample. Elemental analyses and x-ray diffraction results did not indicate notable differences between the two samples. The ICP-MS and Cs-137 data indicate no significant differences in the radionuclide composition of the two SME samples. Semi-volatile organic analysis revealed numerous organic molecules, these likely result from antifoaming additives. The compositions of the two SME samples also match well with the analyzed composition of the SME batch with the exception of significantly higher silicon, lithium, and boron content in the batch sample indicating the coil samples are deficient in frit relative to the SME batch composition.

  20. Titania doping effect on superconducting properties of MgB{sub 2} bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, G; Serquis, A [Institute Balseiro - Centra Atomico Bariloche and CONICET, (8400) S. C. de Bariloche, Rio Negro (Argentina); Bridoux, G, E-mail: serranog@ib.cnea.gov.a [Institute Balseiro - Centra Atomico Bariloche, (8400) S. C. de Bariloche, Rio Negro (Argentina)

    2009-05-01

    In this work we study the microstructural and superconducting properties of doped and undoped bulk MgB{sub 2} samples prepared by solid-state reaction, with 0 and 2.5 %at. nominal TiO{sub 2} nanotubes contents, annealed at different temperatures in the 750-900 deg. C range. We discuss the T{sub c}, J{sub c} and H{sub c2} performance and their correlation with the different synthesis parameters.

  1. Characteristics of slowly cooled Zr-Al-Cu-Ni bulk samples with different oxygen content

    International Nuclear Information System (INIS)

    Gebert, A.; Eckert, J.; Bauer, H.-D.; Schultz, L.

    1998-01-01

    Bulk samples of the glass-forming Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 alloys with 3 mm diameter were prepared by die casting into a copper mould. The oxygen content of the samples was varied between 0.26 at.% and 0.73 at.% by adjusting the oxygen partial pressure in the argon atmosphere upon casting. Characterization of the microstructure of as-cast samples and of specimens continuously heated to 873 K was carried out by X-ray diffraction (XRD), optical microscopy (OM) and transmission electron microscopy (TEM). Thermal stability was investigated by constant-rate differential scanning calorimetry (DSC). The phase formation and the thermal stability of the slowly cooled zirconium-based bulk samples are essentially influenced by the oxygen content of the material. Furthermore, the sensitivity to oxygen depends on the composition of the alloy. In bulk Zr 65 Al 7.5 Cu 17.5 Ni 10 samples only small oxygen traces induce nucleation and crystal growth during slow cooling whereas Zr 55 Al 10 Cu 30 Ni 5 samples are completely amorphous for all oxygen contents investigated. The processes of the oxygen-induced phase formation are discussed in detail also with respect to the results obtained for the heat treated samples. With increasing oxygen content the thermal stability deteriorates, as it is obvious from a diminution of the supercooled liquid region (ΔT x = T x - T g ) which is mainly due to a reduction of the crystallization temperature T x . Furthermore, the thermal behaviour of Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 reveals significant differences. (orig.)

  2. 3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

    Science.gov (United States)

    Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

    2015-01-01

    In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

  3. Trapped field measurements on MgB{sub 2} bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Koblischka, Michael; Karwoth, Thomas; Zeng, XianLin; Hartmann, Uwe [Institute of Experimental Physics, Saarland University, P. O. Box 151150, D-66041 Saarbruecken (Germany); Berger, Kevin; Douine, Bruno [University of Lorraine, GREEN, 54506 Vandoeuvre-les-Nancy (France)

    2016-07-01

    Trapped field measurements were performed on bulk, polycrystalline MgB{sub 2} samples stemming from different sources with the emphasis to develop applications like superconducting permanent magnets ('supermagnets') and electric motors. We describe the setup for the trapped field measurements and the experimental procedure (field cooling, zero-field cooling, field sweep rates). The trapped field measurements were conducted using a cryocooling system to cool the bulk samples to the desired temperatures, and a low-loss cryostat equipped with a room-temperature bore and a maximum field of ±5 T was employed to provide the external magnetic field. The superconducting coil of this cryostat is operated using a bidirectional power supply. Various sweep rates of the external magnetic field ranging between 1 mT/s and 40 mT/s were used to generate the applied field. The measurements were performed with one sample and two samples stacked together. A maximum trapped field of 7 T was recorded. We discuss the results obtained and the problems arising due to flux jumping, which is often seen for the MgB{sub 2} samples cooled to temperatures below 10 K.

  4. WHAT GOVERNS THE BULK VELOCITY OF THE JET COMPONENTS IN ACTIVE GALACTIC NUCLEI?

    International Nuclear Information System (INIS)

    Chai Bo; Cao Xinwu; Gu Minfeng

    2012-01-01

    We use a sample of radio-loud active galactic nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. Based on Königl's inhomogeneous jet model, the jet parameters, such as the bulk motion Lorentz factor, magnetic field strength, and electron density in the jet, can be estimated with the very long baseline interferometry and X-ray data.. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present between the bulk Lorentz factor and the Eddington ratio. The massive black holes will be spun up through accretion, as the black holes acquire mass and angular momentum simultaneously through accretion. Recent investigation indeed suggested that most supermassive black holes in elliptical galaxies have on average higher spins than the black holes in spiral galaxies, where random, small accretion episodes (e.g., tidally disrupted stars, accretion of molecular clouds) might have played a more important role. If this is true, then the correlation between black hole mass and the bulk Lorentz factor of the jet components found in this work implies that the motion velocity of the jet components is probably governed by the black hole spin. No correlation is found between the magnetic field strength at 10R S (R S = 2GM/c 2 is the Schwarzschild radius) in the jets and the bulk Lorentz factor of the jet components for this sample. This is consistent with the black hole spin scenario, i.e., the faster moving jets are magnetically accelerated by the magnetic fields threading the horizon of more rapidly rotating black holes. The results imply that the Blandford-Znajek mechanism may dominate over the Blandford-Payne mechanism for the jet acceleration, at least in these radio-loud AGNs.

  5. Large Sample Neutron Activation Analysis of Heterogeneous Samples

    International Nuclear Information System (INIS)

    Stamatelatos, I.E.; Vasilopoulou, T.; Tzika, F.

    2018-01-01

    A Large Sample Neutron Activation Analysis (LSNAA) technique was developed for non-destructive analysis of heterogeneous bulk samples. The technique incorporated collimated scanning and combining experimental measurements and Monte Carlo simulations for the identification of inhomogeneities in large volume samples and the correction of their effect on the interpretation of gamma-spectrometry data. Corrections were applied for the effect of neutron self-shielding, gamma-ray attenuation, geometrical factor and heterogeneous activity distribution within the sample. A benchmark experiment was performed to investigate the effect of heterogeneity on the accuracy of LSNAA. Moreover, a ceramic vase was analyzed as a whole demonstrating the feasibility of the technique. The LSNAA results were compared against results obtained by INAA and a satisfactory agreement between the two methods was observed. This study showed that LSNAA is a technique capable to perform accurate non-destructive, multi-elemental compositional analysis of heterogeneous objects. It also revealed the great potential of the technique for the analysis of precious objects and artefacts that need to be preserved intact and cannot be damaged for sampling purposes. (author)

  6. Neutron activation analysis for bulk and trace elements in urine

    International Nuclear Information System (INIS)

    Cornelis, R.; Speecke, A.; Hoste, J.

    1975-01-01

    Problems in sampling urine for trace element analysis by neutron activation are systematically examined. Collection, storage, sample preparation and contamination hazards during irradiation are studied in detail. Three different sizes of urine samples are prepared for analysis, depending on the concentration and nuclear properties of the elements, and suitable multielement doped urine standards are used. As, Br, Ca, Cl, Co, Cr, Cs, Cu, Hg, I, K, Mg, Mn, Na, Rb, Se and Zn are determined. The extreme care given to sample collection, use of ''ultra-clean'' vials, and work in a dust-free room allows consistent values to be obtained over long periods of time. A literature review of the amounts of forty elements present in urine per day is also given

  7. Electrical resistance behavior with gamma radiation dose in bulk carbon nanostrutured samples

    International Nuclear Information System (INIS)

    Lage, J.; Leyva, A.; Pinnera, I.; Desdin, L. F.; Abreu, Y.; Cruz, C. M.; Leyva, D.; Toledo, C.

    2013-01-01

    The aim of this paper is to study the effects of 60 Co gamma radiation on the electrical resistance and V-I characteristic of bulk carbon nano structured samples obtained by electric arc discharge in water method. Images of pristine samples obtained with scanning electron, and the results in graphical form of the electrical characterization of irradiated samples are presented in the text. It was observed that the electrical resistance vs. dose behavior shows an initial increment reaching the maximum at approximately 135 kGy, followed by a drop of the resistance values. These behaviors are associated with the progressive generation of radiation induced defects in the sample, whose number increases to reach saturation at 135 kGy. From this dose, defects could lead to cross-links between different nano structures present in the sample conducting to a gradually drop in electrical resistance. The measured V-I curves show that, increasing exposure to the 60 Co gamma radiation, the electrical properties of the studied samples transit from a semiconductor towards a predominantly metallic behavior. These results were compared with those obtained for a sample of graphite powder irradiated under the same conditions. (Author)

  8. Automated Clean Chemistry for Bulk Analysis of Environmental Swipe Samples - FY17 Year End Report

    Energy Technology Data Exchange (ETDEWEB)

    Ticknor, Brian W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Metzger, Shalina C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McBay, Eddy H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hexel, Cole R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tevepaugh, Kayron N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bostick, Debra A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-11-30

    Sample preparation methods for mass spectrometry are being automated using commercial-off-the-shelf (COTS) equipment to shorten lengthy and costly manual chemical purification procedures. This development addresses a serious need in the International Atomic Energy Agency’s Network of Analytical Laboratories (IAEA NWAL) to increase efficiency in the Bulk Analysis of Environmental Samples for Safeguards program with a method that allows unattended, overnight operation. In collaboration with Elemental Scientific Inc., the prepFAST-MC2 was designed based on COTS equipment. It was modified for uranium/plutonium separations using renewable columns packed with Eichrom TEVA and UTEVA resins, with a chemical separation method based on the Oak Ridge National Laboratory (ORNL) NWAL chemical procedure. The newly designed prepFAST-SR has had several upgrades compared with the original prepFAST-MC2. Both systems are currently installed in the Ultra-Trace Forensics Science Center at ORNL.

  9. Use of muonic x rays for nondestructive analysis of bulk samples for low Z constituents

    International Nuclear Information System (INIS)

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

    1978-01-01

    Muonic x rays have been used in quantitative analysis on bulk samples of ''tissue equivalent'' material whose primary constituents are low Z elements (Z less than or equal to 20). The muonic x-ray spectrum resulting from negative muons stopping in ''tissue equivalent'' materials has been obtained. Relative muonic x-ray intensities were determined and correlated with atomic abundances in these materials. A comparison of the results for the various samples is presented. This work establishes the usefulness of this technique for analyses of gross specimens (greater than or equal to few grams) for elements with 6 less than or equal to Z less than or equal to 20 and atomic abundances greater than 0.15 percent

  10. Understanding the effect of surface/bulk defects on the photocatalytic activity of TiO2: anatase versus rutile.

    Science.gov (United States)

    Yan, Junqing; Wu, Guangjun; Guan, Naijia; Li, Landong; Li, Zhuoxin; Cao, Xingzhong

    2013-07-14

    The sole effect of surface/bulk defects of TiO2 samples on their photocatalytic activity was investigated. Nano-sized anatase and rutile TiO2 were prepared by hydrothermal method and their surface/bulk defects were adjusted simply by calcination at different temperatures, i.e. 400-700 °C. High temperature calcinations induced the growth of crystalline sizes and a decrease in the surface areas, while the crystalline phase and the exposed facets were kept unchanged during calcination, as indicated by the characterization results from XRD, Raman, nitrogen adsorption-desorption, TEM and UV-Vis spectra. The existence of surface/bulk defects in calcined TiO2 samples was confirmed by photoluminescence and XPS spectra, and the surface/bulk defect ratio was quantitatively analyzed according to positron annihilation results. The photocatalytic activity of calcined TiO2 samples was evaluated in the photocatalytic reforming of methanol and the photocatalytic oxidation of α-phenethyl alcohol. Based on the characterization and catalytic results, a direct correlation between the surface specific photocatalytic activity and the surface/bulk defect density ratio could be drawn for both anatase TiO2 and rutile TiO2. The surface defects of TiO2, i.e. oxygen vacancy clusters, could promote the separation of electron-hole pairs under irradiation, and therefore, enhance the activity during photocatalytic reaction.

  11. Thermoelastic enhancement of the magnonic spin Seebeck effect in thin films and bulk samples

    Science.gov (United States)

    Chotorlishvili, L.; Wang, X.-G.; Toklikishvili, Z.; Berakdar, J.

    2018-04-01

    A nonuniform temperature profile may generate a pure spin current in magnetic films, as observed, for instance, in the spin Seebeck effect. In addition, thermally induced elastic deformations may set in that could affect the spin current. A self-consistent theory of the magnonic spin Seebeck effect including thermally activated magnetoelastic effects is presented, and analytical expressions for the thermally activated deformation tensor and dispersion relations for coupled magnetoelastic modes are obtained. We derive analytical results for bulk (three-dimensional) systems and thin magnetic (two-dimensional) films. We observe that the displacement vector and the deformation tensor in bulk systems decay asymptotically as u ˜1 /R2 and ɛ ˜1 /R3 , respectively, while the decays in thin magnetic films proceed slower, following u ˜1 /R and ɛ ˜1 /R2 . The dispersion relations evidence a strong anisotropy in the magnetic excitations. We observe that a thermoelastic steady-state deformation may lead to both an enchantment and a reduction of the gap in the magnonic spectrum. The reduction of the gap increases the number of magnons contributing to the spin Seebeck effect and offers new possibilities for the thermoelastic control of the spin Seebeck effect.

  12. δ(15) N from soil to wine in bulk samples and proline.

    Science.gov (United States)

    Paolini, Mauro; Ziller, Luca; Bertoldi, Daniela; Bontempo, Luana; Larcher, Roberto; Nicolini, Giorgio; Camin, Federica

    2016-09-01

    The feasibility of using δ(15) N as an additional isotopic marker able to link wine to its area of origin was investigated. The whole production chain (soil-leaves-grape-wine) was considered. Moreover, the research included evaluation of the effect of the fermentation process, the use of different types of yeast and white and red vinification, the addition of nitrogen adjuvants and ultrasound lysis simulating wine ageing. The δ(15) N of grapes and wine was measured in bulk samples and compounds, specifically in proline, for the first time. Despite isotopic fractionation from soil to wine, the δ(15) N values of leaves, grapes, wine and particularly must and wine proline conserved the variability of δ(15) N in the growing soil. Fermentation and ultrasound treatment did not affect the δ(15) N values of grape must, which was therefore conserved in wine. The addition of inorganic or organic adjuvants was able to influence the δ(15) N of bulk wine, depending on the amount and the difference between the δ(15) N of must and that of the adjuvant. The δ(15) N of wine proline was not influenced by adjuvant addition and is therefore the best marker for tracing the geographical origin of wine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Measurement of the loss on ignition of bulk calcined bauxite samples by neutron moderation

    International Nuclear Information System (INIS)

    Aylmer, J.A.; Borsaru, M.

    1985-01-01

    The production of high-grade calcined bauxite is very dependent on the moisture content of the final product. Existing procedures rely on the ignition of small samples to monitor the effectiveness of the calcination process. The results obtained by this gravimetric technique are several hours behind production and do not permit regular adjustment of the furnace to optimize the control of the chemically bound water content (LOI). To provide rapid and more relevant results, a neutron moderation technique has been developed for measuring the LOI of bulk samples of calcined bauxite while they are still hot. The method uses fast neutrons from an 241 Am-Be neutron source to irradiate the samples, and the backscattered thermal neutrons detected are a measure of bound moisture content. The rms deviation between neutron and conventional determinations of LOI, in 15 calcined bauxite samples, was 0.08 per cent LOI over the range 0.1 to 0.9 per cent LOI. When allowance is made for the rms error in the ignition method, the error in the neutron method is found to be 0.07 per cent LOI

  14. Dynamics and diffusive-conformational coupling in polymer bulk samples and surfaces: a molecular dynamics study

    International Nuclear Information System (INIS)

    Vree, C; Mayr, S G

    2010-01-01

    The impact of free surfaces on the mobility and conformational fluctuations of model polymer chains is investigated with the help of classical molecular dynamics simulations over a broad temperature range. Below a critical temperature, T*, similar to the critical temperature of the mode coupling theory, the center-of-mass displacements and temporal fluctuations of the radius of gyration of individual chains-as a fingerprint of structural reconfigurations-reveal a strong enhancement close to surfaces, while this effect diminishes with increasing temperature and observation time. Interpreting conformational fluctuations as a random walk in conformational space, identical activation enthalpies for structural reconfigurations and diffusion are obtained within the error bars in the bulk and at the surfaces, thus indicating a coupling of diffusive and conformational dynamics.

  15. Implementation of Mass Spectrometry for Bulk Analysis of Environmental and Nuclear Material Inspection Samples

    International Nuclear Information System (INIS)

    Bulyha, S.; Cunningham, A.; Koepf, A.; Macsik, Z.; Poths, J.

    2015-01-01

    In the frame of the ECAS project (Enhancing Capabilities of Safeguards Analytical Services) the IAEA Office of Safeguards Analytical Services has implemented the latest-generation inductively coupled plasma mass spectrometers, or ICP-MS, for (i) bulk analysis of uranium and plutonium isotopes in environmental inspection samples and (ii) impurity analyzes in uranium samples. The measurement accuracy for n(U-235)/ n(U-238) ratios has been improved by approximately five times with the new multi-collector ICP-MS equipment. Use of modern ICP-MS enabled also an improvement of instrumental detection limits for U-233 and U-236 and Pu isotopes by at least one order of magnitude in comparison to the values, which had been achieved with the previously used methods. The improved accuracy and precision for isotope ratio measurements is mainly due to the higher sensitivity and the possibility to simultaneously detect several U isotopes with a multi-collector detector block. Implementation of the ICP-MS has also demonstrated a possibility for an increased sample throughput. In parallel to the implementation of the ICP-MS, a new version of the ''modified total evaporation'' (MTE) method has been developed for isotopic analysis of uranium samples by multi-collector thermal ionization mass spectrometry (TIMS). The MTE method provides a measurement performance which is, in particular for minor uranium isotopes, by several orders of magnitude superior compared to the commonly used ''total evaporation'' method. The new mass spectrometric techniques significantly improve the capability of the IAEA safeguards laboratories to detect the presence of non-natural uranium and plutonium isotopes in environmental swipe samples and to identify previously imperceptible differences in nuclear ''signatures''. Thus, they enhance the IAEA's ability to obtain independent, timely and quality-assured safeguards-relevant data and ensure

  16. Somatic Cells in Bulk Samples and Purchase Prices of Cow Milk

    Directory of Open Access Journals (Sweden)

    Jindřich Kvapilík

    2017-01-01

    Full Text Available There were calculated the somatic cell count (SCC 209 (36 – 468 103ml–1, the total count of microorganisms (TCM 25 103ml–1 (from 5 to 377, fat 3.84 % (from 3.23 to 4.46 and protein content 3.39 % (from 3.04 to 3.75 and milk freezing point (MFP –0.525 °C (from –0.534 to –0.395 of the 522 monthly bulk milk samples from 11 experimental stables during the period from 2012 to 2015. Residues of inhibitory substances were not detected in any sample. Milk sale reached 7,999 liters (l with fluctuating between 6,150 and 10,532 l per cow. This can be deduced from the regression coefficients that due to increase in the SCC by 100 103ml–1 the TCM increased by 2.9 to 4.2 103ml–1, the fat content decreased by 0.09 to 0.13 % and protein about 0.01 to 0.05 %. Influence of SCC, TCM and the fat and protein content calculated from monthly samples for individual stables can be estimated at –0.12 CZC, fluctuations between the stables at +0.46 to –0.84 CZC per l of milk. The increase in milk price by 0.17 CZC in the range of –0.92 to +0.92 CZC per l of milk corresponds to averages of indicators calculated from 522 samples.

  17. Detection of Coxiella burnetii by PCR in bulk tank milk samples from dairy caprine herds in southeast of Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Khalili

    2015-02-01

    Full Text Available Objective: To use PCR for the detection of Coxiella burnetii (C. burnetii in bulk tank milk samples collected from dairy caprine herds in southeast Iran. Methods: In the present study, 31 goat bulk milk from 31 dairy goat herds were tested for C. burnetii using trans-PCR assay. The animals which their milk samples collected for this study were clinically healthy. Results: In total, 5 of 31 (16.12% goat milk samples were positive. Conclusions: The results of this study indicate clinically healthy dairy goats are important sources of C. burnetii infection in this area.

  18. Estimation of the deoxynivalenol and moisture contents of bulk wheat grain samples by FT-NIR spectroscopy

    Science.gov (United States)

    Deoxynivalenol (DON) levels in harvested grain samples are used to evaluate the Fusarium head blight (FHB) resistance of wheat cultivars and breeding lines. Fourier transform near-infrared (FT-NIR) calibrations were developed to estimate the DON and moisture content (MC) of bulk wheat grain samples ...

  19. 40 CFR Appendix E to Subpart E of... - Interim Method of the Determination of Asbestos in Bulk Insulation Samples

    Science.gov (United States)

    2010-07-01

    ... interpretation of point count data 3 is available. This method is applicable to all bulk samples of friable... matrices are not currently available. Data obtained for samples containing a single asbestos type in a... and characterization of fibrous and nonfibrous amphiboles for analytical methods development, pp. 295...

  20. Active moss biomonitoring of trace elements with Sphagnum girgensohnii moss bags in relation to atmospheric bulk deposition in Belgrade, Serbia

    International Nuclear Information System (INIS)

    Anicic, M.; Tasic, M.; Frontasyeva, M.V.; Tomasevic, M.; Rajsic, S.; Mijic, Z.; Popovic, A.

    2009-01-01

    Active biomonitoring with wet and dry moss bags was used to examine trace element atmospheric deposition in the urban area of Belgrade. The element accumulation capability of Sphagnum girgensohnii Russow was tested in relation to atmospheric bulk deposition. Moss bags were mounted for five 3-month periods (July 2005-October 2006) at three representative urban sites. For the same period monthly bulk atmospheric deposition samples were collected. The concentrations of Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, and Pb were determined by instrumental neutron activation analyses and atomic absorption spectrometry. Significant accumulation of most elements occurred in the exposed moss bags compared with the initial moss content. High correlations between the elements in moss and bulk deposits were found for V, Cu, As, and Ni. The enrichment factors of the elements for both types of monitor followed the same pattern at the corresponding sites. - Accumulated trace elements in the moss Sphagnum girgensohnii reflect atmospheric deposition

  1. Effect of sample thickness on the extracted near-infrared bulk optical properties of Bacillus subtilis in liquid culture.

    Science.gov (United States)

    Dzhongova, Elitsa; Harwood, Colin R; Thennadil, Suresh N

    2011-11-01

    In order to determine the bulk optical properties of a Bacillus subtilis culture during growth phase we investigated the effect of sample thickness on measurements taken with different measurement configurations, namely total diffuse reflectance and total diffuse transmittance. The bulk optical properties were extracted by inverting the measurements using the radiative transfer theory. While the relationship between reflectance and biomass changes with sample thickness and the intensity (absorbance) levels vary significantly for both reflectance and transmittance measurements, the extracted optical properties show consistent behavior in terms of both the relationship with biomass and magnitude. This observation indicates the potential of bulk optical properties for building models that could be more easily transferable compared to those built using raw measurements.

  2. Gamma-ray yield dependence on bulk density and moisture content of a sample of a PGNAA setup. A Monte Carlo study

    International Nuclear Information System (INIS)

    Nagadi, M.M.; Naqvi, A.A.

    2007-01-01

    Monte Carlo calculations were carried out to study the dependence of γ-ray yield on the bulk density and moisture content of a sample in a thermalneutron capture-based prompt gamma neutron activation analysis (PGNAA) setup. The results of the study showed a strong dependence of the γ-ray yield upon the sample bulk density. An order of magnitude increase in yield of 1.94 and 6.42 MeV prompt γ-rays from calcium in a Portland cement sample was observed for a corresponding order of magnitude increase in the sample bulk density. On the contrary the γ-ray yield has a weak dependence on sample moisture content and an increase of only 20% in yield of 1.94 and 6.42 MeV prompt γ-rays from calcium in the Portland cement sample was observed for an order of magnitude increase in the moisture content of the Portland cement sample. A similar effect of moisture content has been observed on the yield of 1.167 MeV prompt γ-rays from chlorine contaminants in Portland cement samples. For an order of magnitude increase in the moisture content of the sample, a 7 to 12% increase in the yield of the 1.167 MeV chlorine γ-ray was observed for the Portland cement samples containing 1 to 5 wt.% chlorine contaminants. This study has shown that effects of sample moisture content on prompt γ-ray yield from constituents of a Portland cement sample are insignificant in a thermal-neutrons capture-based PGNAA setup. (author)

  3. Effect of Ca substitution on some physical properties of nano-structured and bulk Ni-ferrite samples

    Science.gov (United States)

    Assar, S. T.; Abosheiasha, H. F.

    2015-01-01

    Nanoparticles of Ni1-xCaxFe2O4 (x=0.0, 0.02, 0.04, 0.06 and 0.10) were prepared by citrate precursor method. A part of these samples was sintered at 600 °C for 2 h in order to keep the particles within the nano-size while the other part was sintered at 1000 °C to let the particles to grow to the bulk size. The effect of Ca2+ ion substitution in nickel ferrite on some structural, magnetic, electrical and thermal properties was investigated. All samples were characterized by using X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). A two probe method was used to measure the dc electrical conductivity whereas the photoacoustic (PA) technique was used to determine the thermal diffusivity of the samples. To interpret different experimental results for nano and bulk samples some cation distributions were assumed based on the VSM and XRD data. These suggested cation distributions give logical explanations for other experimental results such as the observed values of the absorption bands in FTIR spectra and the dc conductivity results. Finally, in the thermal measurements it was found that increasing the Ca2+ ion content causes a decrease in the thermal diffusivity of both nano and bulk samples. The explanation of this behavior is ascribed to the phonon-phonon scattering.

  4. Comparison of platelet activation through hinge vs bulk flow in mechanical heart valves

    Science.gov (United States)

    Hedayat, Mohammadali; Borazjani, Iman

    2017-11-01

    Bileaflet mechanical heart valves increase the risk of thrombus formation in patients which is believed to be initiated by platelet activation. Platelets can be activated by the elevated shear stresses in the bulk flow during the systole phase or the flow through the hinge during the diastole. However, the importance of platelet activation by the bulk flow vs the hinge in MHVs has yet to be studied. Here, we investigate the contribution of each of the above mechanisms to the activation of platelets in MHs by performing simulation of the flow through a 25mm St. Jude Medical valve placed in a straight aorta. Two different gap sizes (250 and 150 micrometer) are used in this study. The simulations are done using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm for FSI solver on overset grids. The platelet activation through the hinge for different gap sizes is compared to the activation in the bulk flow using two platelet activation models to ensure the consistency of the results. Our results for all gap sizes using different activation models show that the integration of platelet activation caused by the bulk flow is several times higher in comparison to the activation through the hinge. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  5. Simulation of Field Dependence of Critical Current Densities of Bulk High Tc Superconducting Materials regarding Thermally Activated Flux Motion

    Science.gov (United States)

    Santosh, M.; Naik, S. Pavan Kumar; Koblischka, M. R.

    2017-07-01

    In the upcoming generation, bulk high temperature superconductors (HTS) will play a crucial and a promising role in numerous industrial applications ranging from Maglev trains to magnetic resonance imaging, etc. Especially, the bulk HTS as permanent magnets are suitable due to the fact that they can trap magnetic fields being several orders of magnitude higher than those of the best hard ferromagnets. The bulk HTS LREBa2Cu3O7-δ (LREBCO or LRE-123, LRE: Y, Gd, etc.,) materials could obtain very powerful compact superconducting super-magnets, which can be operated at the cheaper liquid nitrogen temperature or below due to higher critical temperatures (i.e., ∼90 K). As a result, the new advanced technology can be utilized in a more attractive manner for a variety of technological and medical applications which have the capacity to revolutionize the field. An understanding of the magnetic field dependence of the critical current density (J c(H)) is important to develop better adapted materials. To achieve this goal, a variety of Jc (H) behaviours of bulk LREBCO samples were modelled regarding thermally activated flux motion. In essence, the Jc (H) curves follows a certain criterion where an exponential model is applied. However, to fit the complete Jc (H) curve of the LRE-123 samples an unique model is necessary to explain the behavior at low and high fields. The modelling of the various superconducting materials could be understood in terms of the pinning mechanisms.

  6. Bulk Vitrification Technology For The Treatment And Immobilization Of Low-Activity Waste

    International Nuclear Information System (INIS)

    Ard, K.E.

    2011-01-01

    This report is one of four reports written to provide background information regarding immobilization technologies under consideration for supplemental immobilization of Hanford's low-activity waste. This paper is intended to provide the reader with general understanding of Bulk Vitrification and how it might be applied to immobilization of Hanford's low-activity waste.

  7. BULK VITRIFICATION TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE

    Energy Technology Data Exchange (ETDEWEB)

    ARD KE

    2011-04-11

    This report is one of four reports written to provide background information regarding immobilization technologies under consideration for supplemental immobilization of Hanford's low-activity waste. This paper is intended to provide the reader with general understanding of Bulk Vitrification and how it might be applied to immobilization of Hanford's low-activity waste.

  8. The determination of the bulk density of irradiated samples using a mercury pyknometer

    International Nuclear Information System (INIS)

    Keep, R.H.; Perks, J.M.

    1980-05-01

    A method for determining the bulk density of fragmented UO 2 specimens in the mass range 1 to 10 g by mercury pyknometry has been developed. The factor limiting the accuracy of the technique in this application is the consistency with which the pyknometer can be filled with mercury; this is dependent on the vacuum obtained in the pyknometer prior to filling. It has been found that this method can be used to determine the density of fragments of UO 2 in the mass range specified to an accuracy of better than +- 0.2% (1σ). (author)

  9. Simultaneous assessment of the macrobiome and microbiome in a bulk sample of tropical arthropods through DNA metasystematics.

    Science.gov (United States)

    Gibson, Joel; Shokralla, Shadi; Porter, Teresita M; King, Ian; van Konynenburg, Steven; Janzen, Daniel H; Hallwachs, Winnie; Hajibabaei, Mehrdad

    2014-06-03

    Conventional assessments of ecosystem sample composition are based on morphology-based or DNA barcode identification of individuals. Both approaches are costly and time-consuming, especially when applied to the large number of specimens and taxa commonly included in ecological investigations. Next-generation sequencing approaches can overcome the bottleneck of individual specimen isolation and identification by simultaneously sequencing specimens of all taxa in a bulk mixture. Here we apply multiple parallel amplification primers, multiple DNA barcode markers, 454-pyrosequencing, and Illumina MiSeq sequencing to the same sample to maximize recovery of the arthropod macrobiome and the bacterial and other microbial microbiome of a bulk arthropod sample. We validate this method with a complex sample containing 1,066 morphologically distinguishable arthropods from a tropical terrestrial ecosystem with high taxonomic diversity. Multiamplicon next-generation DNA barcoding was able to recover sequences corresponding to 91% of the distinguishable individuals in a bulk environmental sample, as well as many species present as undistinguishable tissue. 454-pyrosequencing was able to recover 10 more families of arthropods and 30 more species than did conventional Sanger sequencing of each individual specimen. The use of other loci (16S and 18S ribosomal DNA gene regions) also added the detection of species of microbes associated with these terrestrial arthropods. This method greatly decreases the time and money necessary to perform DNA-based comparisons of biodiversity among ecosystem samples. This methodology opens the door to much cheaper and increased capacity for ecological and evolutionary studies applicable to a wide range of socio-economic issues, as well as a basic understanding of how the world works.

  10. Total and non-seasalt sulfate and chloride measured in bulk precipitation samples from the Kilauea Volcano area, Hawaii

    Science.gov (United States)

    Scholl, M.A.; Ingebritsen, S.E.

    1995-01-01

    Six-month cumulative precipitation samples provide estimates of bulk deposition of sulfate and chloride for the southeast part of the Island of Hawaii during four time periods: August 1991 to February 1992, February 1992 to September 1992, March 1993 to September 1993, and September 1993 to February 1994. Total estimated bulk deposition rates for sulfate ranged from 0.12 to 24 grams per square meter per 180 days, and non-seasalt sulfate deposition ranged from 0.06 to 24 grams per square meter per 180 days. Patterns of non-seasalt sulfate deposition were generally related to prevailing wind directions and the proximity of the collection site to large sources of sulfur gases, namely Kilauea Volcano's summit and East Rift Zone eruption. Total chloride deposition from bulk precipitation samples ranged from 0.01 to 17 grams per square meter per 180 days. Chloride appeared to be predominantly from oceanic sources, as non- seasalt chloride deposition was near zero for most sites.

  11. Fiber Bragg grating based spatially resolved characterization of flux-pinning induced strain of rectangular-shaped bulk YBCO samples

    International Nuclear Information System (INIS)

    Latka, Ines; Habisreuther, Tobias; Litzkendorf, Doris

    2011-01-01

    Highlights: → Fiber Bragg gratings (FBG) act as strain sensors, also at cryogenic temperatures. → FBGs are not sensitive to magnetic fields. → Local, shape dependent magnetostriction was detected on rectangular samples. → Magnetostrictive effects of the top surface and in a gap between two samples are different. - Abstract: We report on measurements of the spatially resolved characterization of flux-pinning induced strain of rectangular-shaped bulk YBCO samples. The spatially resolved strain measurements are accomplished by the use 2 fiber Bragg grating arrays, which are with an included angle of 45 o fixed to the surface. In this paper first attempts to confirm the shape distortions caused by the flux-pinning induced strain as predicted in will be presented. Two sample setups, a single bulk and a 'mirror' arrangement, will be compared. This mirror setup represents a model configuration for a measurement inside the superconductor, where demagnetization effects can be neglected and the magnetic field merely has a z-component.

  12. Management experience on microthrix parvicella bulking in an activated sludge wastewater treatment plant

    International Nuclear Information System (INIS)

    De Bortoli, N.; Mion, M.; Di Giorgio, G.; Goi, D.

    2005-01-01

    Activated sludge wastewater treatment processes may give inefficiencies due to biological imbalances involving biomass. In fact, external causes as temperature lowering can increase the proliferation of the filamentous bacterium Microthrix parvicella into activated sludge flocks. Microthrix parvicella increases may create dangerous bulking phenomena compromising secondary settling without varying bio-kinetic parameters. In this case of study, a method to defeat growth of Microthrix parvicella has been set up. Aluminium poly-chloride (PAC) has been added to activated sludge contained into oxidation tanks of a municipal wastewater treatment plant, where a large growth of Microthrix parvicella has been periodically observed. It has been demonstrated that a definite PAC concentration can reduce Microthrix parvicella proliferation into activated sludge flocks so bulking phenomena can be well reduced [it

  13. Composition and activity variations in bulk gas of drum waste packages of Paks NPP

    International Nuclear Information System (INIS)

    Molnar, M.; Palcsu, L.; Svingor, E.; Szanto, Zs.; Futo, I.; Ormai, P.

    2001-01-01

    To obtain reliable estimates of the quantities and rates of the gas production a series of measurements was carried out in drum waste packages generated and temporarily stored at the site of Paks Nuclear Power Plant (Paks NPP). Ten drum waste packages were equipped with sampling valves for repeated sampling. Nine times between 04/02/2000 and 19/07/2001 qualitative gas component analyses of bulk gases of drums were executed. Gas samples were delivered to the laboratory of the ATOMKI for tritium and radiocarbon content measurements.(author)

  14. Multicounter neutron detector for examination of content and spatial distribution of fissile materials in bulk samples

    International Nuclear Information System (INIS)

    Swiderska-Kowalczyk, M.; Starosta, W.; Zoltowski, T.

    1999-01-01

    A new neutron coincidence well-counter is presented. This experimental device can be applied for passive assay of fissile and, in particular, for plutonium bearing materials. It contains of a set of the 3 He tubes placed inside a polyethylene moderator. Outputs from the tubes, first processed by preamplifier/amplifier/discriminator circuits, are then analysed using a correlator connected with PC, and correlation techniques implemented in software. Such a neutron counter enables determination of the 240 Pu effective mass in samples of a small Pu content (i.e., where the multiplication effects can be neglected) having a fairly big volume (up to 0.17 m 3 ), if only the isotopic composition is known. For determination of neutron sources distribution inside a sample, a heuristic method based on hierarchical cluster analysis was applied. As input parameters, amplitudes and phases of two-dimensional Fourier transformation of the count profiles matrices for known point sources distributions and for the examined samples were taken. Such matrices of profiles counts are collected using the sample scanning with detection head. In the clustering processes, process, counts profiles of unknown samples are fitted into dendrograms employing the 'proximity' criterion of the examined sample profile to standard samples profiles. Distribution of neutron sources in the examined sample is then evaluated on the basis of a comparison with standard sources distributions. (author)

  15. Fish sampling with active methods

    Czech Academy of Sciences Publication Activity Database

    Kubečka, Jan; Godo, O. R.; Hickley, P.; Prchalová, Marie; Říha, Milan; Rudstam, L.; Welcomme, R.

    2012-01-01

    Roč. 123, July (2012), s. 1-3 ISSN 0165-7836 Institutional support: RVO:60077344 Keywords : fish stock assessment * active and passive gear * intercalibration Subject RIV: EH - Ecology, Behaviour Impact factor: 1.695, year: 2012

  16. Critical current density improvements in MgB2 superconducting bulk samples by K2CO3 additions  

    DEFF Research Database (Denmark)

    Grivel, J.-C.

    2018-01-01

    MgB2 bulk samples with potassium carbonate doping were made by means of reaction of elemental Mg and B powders mixed with various amounts of K2CO3. The Tc of the superconducting phase as well as its a-axis parameter were decreased as a result of carbon doping. Potassium escaped the samples during...... reaction. The critical current density of MgB2 was improved both in self field and under applied magnetic field for T ≤ 30 K, with optimum results for 1 mol% K2CO3 addition. The normalized flux pinning force (f(b)) shows that the flux pinning mechanism at low field is similar for all samples, following...

  17. Non-destructive identification of micrometer-scale minerals and their position within a bulk sample

    DEFF Research Database (Denmark)

    Sørensen, Henning O.; Hakim, Sepide S.; Pedersen, Stefan

    2012-01-01

    . Crushing or disintegrating a sample annihilates any possibility for gathering information from the texture of the porous media or the mineral assemblage close to the grains in question. A new method using three-dimensional X-ray diffraction (3DXRD) microscopy can be successfully applied to natural...... materials. We combined X-ray microtomography (XMT) and 3DXRD to investigate a sample of very fine-grained chalk containing fracture minerals. The XMT technique provides three-dimensional images of the particles and pore structure at very high resolution (350 nm voxel dimension) on samples less than 500 μm......Using the conventional techniques of mineralogy, it has been a challenge to determine mineral identity, crystal orientation and spatial position of micrometer-sized crystals that are embedded in a rock, sediment or soil. Traditionally, the individual grains must be extracted and analyzed separately...

  18. Molecular detection of Coxiella burnetii in goat bulk milk samples in ...

    African Journals Online (AJOL)

    use

    2011-12-14

    Dec 14, 2011 ... useful for the diagnosis of acute infection due to the delay in antibody development. Furthermore, it is ... reaction (PCR) assay has become a useful tool for the detection of C. burnetii in clinical samples .... the efficiency of control schemes aimed at controlling and/or preventing C. burnetii infection in dairy.

  19. Feasibility of surface sampling in automated inspection of concrete aggregates during bulk transport on a conveyor

    NARCIS (Netherlands)

    Bakker, M.C.M.; Di Maio, F.; Lotfi, S.; Bakker, M.; Hu, M.; Vahidi, A.

    2017-01-01

    Automated optic inspection of concrete aggregates for pollutants (e.g. wood, plastics, gypsum and brick) is required to establish the suitability for reuse in new concrete products. Inspection is more efficient when directly sampling the materials on the conveyor belt instead of feeding them in a

  20. Effect of sample geometry on bulk relative density of hot-mix asphalt mixes

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2011-09-01

    Full Text Available with different number of cut/cored surfaces. Significant variations in voids were observed in the HMA core and beam samples from the same compacted slabs. The objective of this paper is to present the findings of the effect of specimen geometry and cut surfaces...

  1. Oak ridge national laboratory automated clean chemistry for bulk analysis of environmental swipe samples

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, Debra A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hexel, Cole R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ticknor, Brian W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tevepaugh, Kayron N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Metzger, Shalina C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-11-01

    To shorten the lengthy and costly manual chemical purification procedures, sample preparation methods for mass spectrometry are being automated using commercial-off-the-shelf (COTS) equipment. This addresses a serious need in the nuclear safeguards community to debottleneck the separation of U and Pu in environmental samples—currently performed by overburdened chemists—with a method that allows unattended, overnight operation. In collaboration with Elemental Scientific Inc., the prepFAST-MC2 was designed based on current COTS equipment that was modified for U/Pu separations utilizing Eichrom™ TEVA and UTEVA resins. Initial verification of individual columns yielded small elution volumes with consistent elution profiles and good recovery. Combined column calibration demonstrated ample separation without crosscontamination of the eluent. Automated packing and unpacking of the built-in columns initially showed >15% deviation in resin loading by weight, which can lead to inconsistent separations. Optimization of the packing and unpacking methods led to a reduction in the variability of the packed resin to less than 5% daily. The reproducibility of the automated system was tested with samples containing 30 ng U and 15 pg Pu, which were separated in a series with alternating reagent blanks. These experiments showed very good washout of both the resin and the sample from the columns as evidenced by low blank values. Analysis of the major and minor isotope ratios for U and Pu provided values well within data quality limits for the International Atomic Energy Agency. Additionally, system process blanks spiked with 233U and 244Pu tracers were separated using the automated system after it was moved outside of a clean room and yielded levels equivalent to clean room blanks, confirming that the system can produce high quality results without the need for expensive clean room infrastructure. Comparison of the amount of personnel time necessary for successful manual vs

  2. Sample container for neutron activation analysis

    International Nuclear Information System (INIS)

    Lersmacher, B.; Verheijke, M.L.; Jaspers, H.J.

    1983-01-01

    The sample container avoids contaminating the sample substance by diffusion of foreign matter from the wall of the sample container into the sample. It cannot be activated, so that the results of measurements are not falsified by a radioactive container wall. It consists of solid carbon. (orig./HP) [de

  3. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology - Quantifying and modelling filamentous bulking.

    Science.gov (United States)

    Wágner, Dorottya S; Ramin, Elham; Szabo, Peter; Dechesne, Arnaud; Plósz, Benedek Gy

    2015-07-01

    The objective of this work is to identify relevant settling velocity and rheology model parameters and to assess the underlying filamentous microbial community characteristics that can influence the solids mixing and transport in secondary settling tanks. Parameter values for hindered, transient and compression settling velocity functions were estimated by carrying out biweekly batch settling tests using a novel column setup through a four-month long measurement campaign. To estimate viscosity model parameters, rheological experiments were carried out on the same sludge sample using a rotational viscometer. Quantitative fluorescence in-situ hybridisation (qFISH) analysis, targeting Microthrix parvicella and phylum Chloroflexi, was used. This study finds that M. parvicella - predominantly residing inside the microbial flocs in our samples - can significantly influence secondary settling through altering the hindered settling velocity and yield stress parameter. Strikingly, this is not the case for Chloroflexi, occurring in more than double the abundance of M. parvicella, and forming filaments primarily protruding from the flocs. The transient and compression settling parameters show a comparably high variability, and no significant association with filamentous abundance. A two-dimensional, axi-symmetrical computational fluid dynamics (CFD) model was used to assess calibration scenarios to model filamentous bulking. Our results suggest that model predictions can significantly benefit from explicitly accounting for filamentous bulking by calibrating the hindered settling velocity function. Furthermore, accounting for the transient and compression settling velocity in the computational domain is crucial to improve model accuracy when modelling filamentous bulking. However, the case-specific calibration of transient and compression settling parameters as well as yield stress is not necessary, and an average parameter set - obtained under bulking and good settling

  4. Thermally activated reaction–diffusion-controlled chemical bulk reactions of gases and solids

    Directory of Open Access Journals (Sweden)

    S. Möller

    2015-01-01

    Full Text Available The chemical kinetics of the reaction of thin films with reactive gases is investigated. The removal of thin films using thermally activated solid–gas to gas reactions is a method to in-situ control deposition inventory in vacuum and plasma vessels. Significant scatter of experimental deposit removal rates at apparently similar conditions was observed in the past, highlighting the need for understanding the underlying processes. A model based on the presence of reactive gas in the films bulk and chemical kinetics is presented. The model describes the diffusion of reactive gas into the film and its chemical interaction with film constituents in the bulk using a stationary reaction–diffusion equation. This yields the reactive gas concentration and reaction rates. Diffusion and reaction rate limitations are depicted in parameter studies. Comparison with literature data on tokamak co-deposit removal results in good agreement of removal rates as a function of pressure, film thickness and temperature.

  5. Structure and soft magnetic properties of the bulk samples prepared by compaction of the mixtures of Co-based and Fe-based powders

    International Nuclear Information System (INIS)

    Fuezer, J.; Bednarcik, J.; Kollar, P.; Roth, S.

    2007-01-01

    Ball milling of CoFeZrB ribbons and subsequent compaction of the resulting powders were used to prepare bulk amorphous samples. Further, two sets of powder samples were prepared by cryomilling of FeCuNbMoSiB alloy in amorphous and nanocrystalline state. Amorphous and nanocrystalline FeCuNbMoSiB powders were blended with CoFeZrB powder at different concentrations. Such powder mixtures were consolidated and several bulk nanocomposites have been synthesized. An addition of nanocrystalline or amorphous FeCuNbMoSiB powder to amorphous CoFeZrB powder caused a decrease of the magnetostriction of the resultant bulk samples, while the coercivity shows an opposite behavior. Our results show that the powder consolidation by hot pressing is an alternative method for the preparation of bulk metallic glasses, which are difficult to prepare by casting methods

  6. Large sample neutron activation analysis of a reference inhomogeneous sample

    International Nuclear Information System (INIS)

    Vasilopoulou, T.; Athens National Technical University, Athens; Tzika, F.; Stamatelatos, I.E.; Koster-Ammerlaan, M.J.J.

    2011-01-01

    A benchmark experiment was performed for Neutron Activation Analysis (NAA) of a large inhomogeneous sample. The reference sample was developed in-house and consisted of SiO 2 matrix and an Al-Zn alloy 'inhomogeneity' body. Monte Carlo simulations were employed to derive appropriate correction factors for neutron self-shielding during irradiation as well as self-attenuation of gamma rays and sample geometry during counting. The large sample neutron activation analysis (LSNAA) results were compared against reference values and the trueness of the technique was evaluated. An agreement within ±10% was observed between LSNAA and reference elemental mass values, for all matrix and inhomogeneity elements except Samarium, provided that the inhomogeneity body was fully simulated. However, in cases that the inhomogeneity was treated as not known, the results showed a reasonable agreement for most matrix elements, while large discrepancies were observed for the inhomogeneity elements. This study provided a quantification of the uncertainties associated with inhomogeneity in large sample analysis and contributed to the identification of the needs for future development of LSNAA facilities for analysis of inhomogeneous samples. (author)

  7. Single-cell vs. bulk activity properties of coastal bacterioplankton over an annual cycle in a temperate ecosystem.

    Science.gov (United States)

    Morán, Xosé Anxelu G; Calvo-Díaz, Alejandra

    2009-01-01

    The connections between single-cell activity properties of heterotrophic planktonic bacteria and whole community metabolism are still poorly understood. Here, we show flow cytometry single-cell analysis of membrane-intact (live), high nucleic acid (HNA) content and actively respiring (CTC+) bacteria with samples collected monthly during 2006 in northern Spain coastal waters. Bulk activity was assessed by measuring 3H-Leucine incorporation and specific growth rates. Consistently, different single-cell relative abundances were found, with 60-100% for live, 30-84% for HNA and 0.2-12% for CTC+ cells. Leucine incorporation rates (2-153 pmol L(-1) h(-1)), specific growth rates (0.01-0.29 day(-1)) and the total and relative abundances of the three single-cell groups showed marked seasonal patterns. Distinct depth distributions during summer stratification and different relations with temperature, chlorophyll and bacterial biovolume suggest the existence of different controlling factors on each single-cell property. Pooled leucine incorporation rates were similarly correlated with the abundance of all physiological groups, while specific growth rates were only substantially explained by the percentage of CTC+ cells. However, the ability to reduce CTC proved notably better than the other two single-cell properties at predicting bacterial bulk rates within seasons, suggesting a tight linkage between bacterial individual respiration and biomass production at the community level.

  8. Measurement of neutron activation in concrete samples

    International Nuclear Information System (INIS)

    Zagar, T.; Ravnik, M.

    2000-01-01

    The results of activation studies of ordinary and barytes concrete samples relevant for research reactor decommissioning are given. Five important long-lived radioactive isotopes ( 54 Mn, 60 Co, 65 Zn, 133 Ba, and 152 Eu) were identified from the gamma-ray spectra measured in the irradiated concrete samples. Activation of these samples was also calculated using ORIGEN2 code. Comparison of calculated and measured results is given. (author)

  9. Quantitative monitoring of activity-dependent bulk endocytosis of synaptic vesicle membrane by fluorescent dextran imaging

    Science.gov (United States)

    Clayton, Emma Louise; Cousin, Michael Alan

    2012-01-01

    Activity-dependent bulk endocytosis (ADBE) is the dominant synaptic vesicle (SV) retrieval mode in central nerve terminals during periods of intense neuronal activity. Despite this fact there are very few real time assays that report the activity of this critical SV retrieval mode. In this paper we report a simple and quantitative assay of ADBE using uptake of large flourescent dextrans as fluid phase markers. We show that almost all dextran uptake occurs in nerve terminals, using co-localisation with the fluorescent probe FM1-43. We also demonstrate that accumulated dextran cannot be unloaded by neuronal stimulation, indicating its specific loading into bulk endosomes and not SVs. Quantification of dextran uptake was achieved by using thresholding analysis to count the number of loaded nerve terminals, since monitoring the average fluorescence intensity of these nerve terminals did not accurately report the extent of ADBE. Using this analysis we showed that dextran uptake occurs very soon after stimulation and that it does not persist when stimulation terminates. Thus we have devised a simple and quantitative method to monitor ADBE in living neurones, which will be ideal for real time screening of small molecule inhibitors of this key SV retrieval mode. PMID:19766140

  10. Irreversibility line and magnetic field dependence of the critical current in superconducting MgB sub 2 bulk samples

    CERN Document Server

    Gioacchino, D D; Tripodi, P; Grimaldi, G

    2003-01-01

    The third harmonic components of the ac susceptibility of MgB sub 2 bulk samples have been measured as a function of applied magnetic fields, together with standard magnetization cycles. The irreversibility line (IL) of the magnetic field has been extracted from the onset of the third harmonic components. Using a (1 - t) supalpha glass/liquid best fit where alpha 1.27 IL shows a coherent length xi divergence with exponent nu = 0.63, which indicates a 3D behaviour. Moreover, using the numerical solution of the non-linear magnetic diffusion equation, considering the creep model in a 3D vortex glass, a good description of the vortex dynamics has been obtained. The behaviour of the magnetization amplitude (approx Hz) and the ac susceptibility signals (kHz), at different applied magnetic fields, 3.5 T < H sub d sub c < 4.5 T, and at the reduced temperature 0.86 < t < 0.93 (T = 22 K), shows that the superconducting dynamic response of vortices in the MgB sub 2 samples is not evidently dependent on the f...

  11. Plasma treatment of bulk niobium surface for superconducting rf cavities: Optimization of the experimental conditions on flat samples

    Directory of Open Access Journals (Sweden)

    M. Rašković

    2010-11-01

    Full Text Available Accelerator performance, in particular the average accelerating field and the cavity quality factor, depends on the physical and chemical characteristics of the superconducting radio-frequency (SRF cavity surface. Plasma based surface modification provides an excellent opportunity to eliminate nonsuperconductive pollutants in the penetration depth region and to remove the mechanically damaged surface layer, which improves the surface roughness. Here we show that the plasma treatment of bulk niobium (Nb presents an alternative surface preparation method to the commonly used buffered chemical polishing and electropolishing methods. We have optimized the experimental conditions in the microwave glow discharge system and their influence on the Nb removal rate on flat samples. We have achieved an etching rate of 1.7  μm/min⁡ using only 3% chlorine in the reactive mixture. Combining a fast etching step with a moderate one, we have improved the surface roughness without exposing the sample surface to the environment. We intend to apply the optimized experimental conditions to the preparation of single cell cavities, pursuing the improvement of their rf performance.

  12. Identification of rhenium donors and sulfur vacancy acceptors in layered MoS{sub 2} bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Brandão, F. D., E-mail: fdbrand@fisica.ufmg.br; Ribeiro, G. M.; Vaz, P. H.; González, J. C.; Krambrock, K. [Departamento de Física, Universidade Federal de Minas Gerais, CP 702, 30.123-970 Belo Horizonte, MG (Brazil)

    2016-06-21

    MoS{sub 2} monolayers, a two-dimensional (2D) direct semiconductor material with an energy gap of 1.9 eV, offer many opportunities to be explored in different electronic devices. Defects often play dominant roles in the electronic and optical properties of semiconductor devices. However, little experimental information about intrinsic and extrinsic defects or impurities is available for this 2D system, and even for macroscopic 3D samples for which MoS{sub 2} shows an indirect bandgap of 1.3 eV. In this work, we evaluate the nature of impurities with unpaired spins using electron paramagnetic resonance (EPR) in different geological macroscopic samples. Regarding the fact that monolayers are mostly obtained from natural crystals, we expect that the majority of impurities found in macroscopic samples are also randomly present in MoS{sub 2} monolayers. By EPR at low temperatures, rhenium donors and sulfur vacancy acceptors are identified as the main impurities in bulk MoS{sub 2} with a corresponding donor concentration of about 10{sup 8–12} defects/cm{sup 2} for MoS{sub 2} monolayer. Electrical transport experiments as a function of temperature are in good agreement with the EPR results, revealing a shallow donor state with an ionization energy of 89 meV and a concentration of 7 × 10{sup 15 }cm{sup −3}, which we attribute to rhenium, as well as a second deeper donor state with ionization energy of 241 meV with high concentration of 2 × 10{sup 19 }cm{sup −3} and net acceptor concentration of 5 × 10{sup 18 }cm{sup −3} related to sulfur vacancies.

  13. Neutron activation analysis of geochemical samples

    International Nuclear Information System (INIS)

    Rosenberg, R.; Zilliacus, R.; Kaistila, M.

    1983-06-01

    The present paper will describe the work done at the Technical Research Centre of Finland in developing methods for the large-scale activation analysis of samples for the geochemical prospecting of metals. The geochemical prospecting for uranium started in Finland in 1974 and consequently a manually operated device for the delayed neutron activation analysis of uranium was taken into use. During 1974 9000 samples were analyzed. The small capacity of the analyzer made it necessary to develop a completely automated analyzer which was taken into use in August 1975. Since then 20000-30000 samples have been analyzed annually the annual capacity being about 60000 samples when running seven hours per day. Multielemental instrumental neutron activation analysis is used for the analysis of more than 40 elements. Using instrumental epithermal neutron activation analysis 25-27 elements can be analyzed using one irradiation and 20 min measurement. During 1982 12000 samples were analyzed for mining companies and Geological Survey of Finland. The capacity is 600 samples per week. Besides these two analytical methods the analysis of lanthanoids is an important part of the work. 11 lanthanoids have been analyzed using instrumental neutron activation analysis. Radiochemical separation methods have been developed for several elements to improve the sensitivity of the analysis

  14. Instrumental neutron activation analysis of soil sample

    International Nuclear Information System (INIS)

    Abdul Khalik Haji Wood.

    1983-01-01

    This paper describes the analysis of soil samples collected from 5 different location around Sungai Lui, Kajang, Selangor, Malaysia. These sample were taken at 22-24 cm from the top of the ground and were analysed using the techniques of Instrumental Neutron Activation Analysis (INAA). The analysis on soil sample taken above 22-24 cm level were done in order to determine if there is any variation in elemental contents at different sampling levels. The results indicate a wide variation in the contents of the samples. About 30 elements have been analysed. The major ones are Na, I, Cl, Mg, Al, K, Ti, Ca and Fe. Trace elements analysed were Ba, Sc, V, Cr, Mn, Ga, As, Zn, Br, Rb, Co, Hf, Zr, Th, U, Sb, Cs, Ce, Sm, Eu, Tb, Dy, Yb, Lu and La. (author)

  15. Study on the influence of X-ray tube spectral distribution on the analysis of bulk samples and thin films: Fundamental parameters method and theoretical coefficient algorithms

    International Nuclear Information System (INIS)

    Sitko, Rafal

    2008-01-01

    Knowledge of X-ray tube spectral distribution is necessary in theoretical methods of matrix correction, i.e. in both fundamental parameter (FP) methods and theoretical influence coefficient algorithms. Thus, the influence of X-ray tube distribution on the accuracy of the analysis of thin films and bulk samples is presented. The calculations are performed using experimental X-ray tube spectra taken from the literature and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al. (X-Ray Spectrom. 14 (1985) 125-135), Ebel (X-Ray Spectrom. 28 (1999) 255-266), and Finkelshtein and Pavlova (X-Ray Spectrom. 28 (1999) 27-32). In this study, Fe-Cr-Ni system is selected as an example and the calculations are performed for X-ray tubes commonly applied in X-ray fluorescence analysis (XRF), i.e., Cr, Mo, Rh and W. The influence of X-ray tube spectra on FP analysis is evaluated when quantification is performed using various types of calibration samples. FP analysis of bulk samples is performed using pure-element bulk standards and multielement bulk standards similar to the analyzed material, whereas for FP analysis of thin films, the bulk and thin pure-element standards are used. For the evaluation of the influence of X-ray tube spectra on XRF analysis performed by theoretical influence coefficient methods, two algorithms for bulk samples are selected, i.e. Claisse-Quintin (Can. Spectrosc. 12 (1967) 129-134) and COLA algorithms (G.R. Lachance, Paper Presented at the International Conference on Industrial Inorganic Elemental Analysis, Metz, France, June 3, 1981) and two algorithms (constant and linear coefficients) for thin films recently proposed by Sitko (X-Ray Spectrom. 37 (2008) 265-272)

  16. Diagnostic performance of an indirect enzyme-linked immunosorbent assay (ELISA) to detect bovine leukemia virus antibodies in bulk-tank milk samples

    Science.gov (United States)

    Nekouei, Omid; Durocher, Jean; Keefe, Greg

    2016-01-01

    This study assessed the diagnostic performance of a commercial ELISA for detecting bovine leukemia virus antibodies in bulk-tank milk samples from eastern Canada. Sensitivity and specificity of the test were estimated at 97.2% and 100%, respectively. The test was recommended as a cost-efficient tool for large-scale screening programs. PMID:27429469

  17. Windowed active sampling for reliable neural learning

    NARCIS (Netherlands)

    Barakova, E.I; Spaanenburg, L

    The composition of the example set has a major impact on the quality of neural learning. The popular approach is focused on extensive pre-processing to bridge the representation gap between process measurement and neural presentation. In contrast, windowed active sampling attempts to solve these

  18. Analytical tools for determination of new oral antidiabetic drugs, glitazones, gliptins, gliflozins and glinides, in bulk materials, pharmaceuticals and biological samples

    Directory of Open Access Journals (Sweden)

    Gumieniczek Anna

    2016-01-01

    Full Text Available The review presents analytical methods for determination of new oral drugs for the treatment of type 2 diabetes mellitus (T2DM, focusing on peroxisome proliferator-activated receptor gamma agonists (glitazones, dipeptidyl peptidase 4 inhibitors (gliptins and sodium/glucose co-transporter 2 inhibitors (gliflozins. Drugs derived from prandial glucose regulators, such as glinides, are considered because they are present in some new therapeutic options. The review presents analytical procedures suitable for determination of the drugs in bulk substances, such as pharmaceuticals and biological samples, including HPLC-UV, HPLC/LC-MS, TLC/HPTLC, CE/CE-MS, spectrophotometric (UV/VIS, spectrofluorimetric and electrochemical methods, taken from the literature over the past ten years (2006-2016. Some new procedures for extraction, separation and detection of the drugs, including solid phase extraction with molecularly imprinted polymers (SPE-MIP, liquid phase microextraction using porous hollow fibers (HP-LPME, HILIC chromatography, micellar mobile phases, ion mobility spectrometry (IMS and isotopically labeled internal standards, are discussed.

  19. Different bulk and active bacterial communities in cryoconite from the margin and interior of the Greenland ice sheet

    DEFF Research Database (Denmark)

    Stibal, Marek; Schostag, Morten; Cameron, Karen A.

    2015-01-01

    composition of cryoconite over a melt season at two contrasting sites at the margin and in the interior of the Greenland ice sheet, using sequence analysis and quantitative polymerase chain reaction of coextracted 16S rDNA and rRNA. Significant differences were found between bulk (rDNA) and potentially active...

  20. Modelling and comparison of trapped fields in (RE)BCO bulk superconductors for activation using pulsed field magnetization

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Ujiie, T.; Zou, J.; Dennis, A. R.; Shi, Y.-H.; Cardwell, D. A.

    2014-06-01

    The ability to generate a permanent, stable magnetic field unsupported by an electromotive force is fundamental to a variety of engineering applications. Bulk high temperature superconducting (HTS) materials can trap magnetic fields of magnitude over ten times higher than the maximum field produced by conventional magnets, which is limited practically to rather less than 2 T. In this paper, two large c-axis oriented, single-grain YBCO and GdBCO bulk superconductors are magnetized by the pulsed field magnetization (PFM) technique at temperatures of 40 and 65 K and the characteristics of the resulting trapped field profile are investigated with a view of magnetizing such samples as trapped field magnets (TFMs) in situ inside a trapped flux-type superconducting electric machine. A comparison is made between the temperatures at which the pulsed magnetic field is applied and the results have strong implications for the optimum operating temperature for TFMs in trapped flux-type superconducting electric machines. The effects of inhomogeneities, which occur during the growth process of single-grain bulk superconductors, on the trapped field and maximum temperature rise in the sample are modelled numerically using a 3D finite-element model based on the H-formulation and implemented in Comsol Multiphysics 4.3a. The results agree qualitatively with the observed experimental results, in that inhomogeneities act to distort the trapped field profile and reduce the magnitude of the trapped field due to localized heating within the sample and preferential movement and pinning of flux lines around the growth section regions (GSRs) and growth sector boundaries (GSBs), respectively. The modelling framework will allow further investigation of various inhomogeneities that arise during the processing of (RE)BCO bulk superconductors, including inhomogeneous Jc distributions and the presence of current-limiting grain boundaries and cracks, and it can be used to assist optimization of

  1. Critical current density in MgB2 bulk samples after co-doping with nano-SiC and poly zinc acrylate complexes

    International Nuclear Information System (INIS)

    Zhang, Z.; Suo, H.; Ma, L.; Zhang, T.; Liu, M.; Zhou, M.

    2011-01-01

    SiC and poly zinc acrylate complexes co-doped MgB 2 bulk has been synthesized. Co-doping can cause higher carbon substitutions and the second phase particles. Co-doping can further increase the Jc value of MgB 2 bulk on the base of the SiC doping. The co-doped MgB 2 bulk samples have been synthesized using an in situ reaction processing. The additives is 8 wt.% SiC nano powders and 10 wt.% [(CH 2 CHCOO) 2 Zn] n poly zinc acrylate complexes (PZA). A systematic study was performed on samples doped with SiC or PZA and samples co-doped with both of them. The effects of doping and co-doping on phase formation, microstructure, and the variation of lattice parameters were studied. The amount of substituted carbon, the critical temperature (T c ) and the critical current density (J c ) were determined. The calculated lattice parameters show the decrease of the a-axis, while no obvious change was detected for c-axis parameter in co-doped samples. This indicates that the carbon was substituted by boron in MgB 2 . The amount of substituted carbon for the co-doped sample shows an enhancement compared to that of the both single doped samples. The co-doped samples perform the highest J c values, which reaches 3.3 x 10 4 A/cm 2 at 5 K and 7 T. It is shown that co-doping with SiC and organic compound is an effective way to further improve the superconducting properties of MgB 2 .

  2. Neutron activation analysis of wheat samples

    International Nuclear Information System (INIS)

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

    2011-01-01

    The deficiency of essential micronutrients and excess of toxic metals in cereals, an important food items for human nutrition, can cause public health risk. Therefore, before their consumption and adoption of soil supplementation, concentrations of essential micronutrients and metals in cereals should be monitored. This study collected soil and two varieties of wheat samples-Triticum aestivum L. (Jordao/bread wheat), and Triticum durum L. (Marialva/durum wheat) from Elvas area, Portugal and analyzed concentrations of As, Cr, Co, Fe, K, Na, Rb and Zn using Instrumental Neutron Activation Analysis (INAA) to focus on the risk of adverse public health issues. The low variability and moderate concentrations of metals in soils indicated a lower significant effect of environmental input on metal concentrations in agricultural soils. The Cr and Fe concentrations in soils that ranged from 93-117 and 26,400-31,300 mg/kg, respectively, were relatively high, but Zn concentration was very low (below detection limit Fe>Na>Zn>Cr>Rb>As>Co. Concentrations of As, Co and Cr in root, straw and spike of both varieties were higher than the permissible limits with exception of a few samples. The concentrations of Zn in root, straw and spike were relatively low (4-30 mg/kg) indicating the deficiency of an essential micronutrient Zn in wheat cultivated in Portugal. The elemental transfer from soil to plant decreases with increasing growth of the plant. The concentrations of various metals in different parts of wheat followed the order: Root>Straw>Spike. A few root, straw and spike samples showed enrichment of metals, but the majority of the samples showed no enrichment. Potassium is enriched in all samples of root, straw and spike for both varieties of wheat. Relatively to the seed used for cultivation, Jordao presented higher transfer coefficients than Marialva, in particular for Co, Fe, and Na. The Jordao and Marialva cultivars accumulated not statistically significant different

  3. Neutron activation analysis of wheat samples

    Energy Technology Data Exchange (ETDEWEB)

    Galinha, C. [CERENA-IST, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Anawar, H.M. [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Freitas, M.C., E-mail: cfreitas@itn.pt [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Pacheco, A.M.G. [CERENA-IST, Technical University of Lisbon, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Almeida-Silva, M. [Instituto Tecnoclogico e Nuclear, URSN, E.N. 10, 2686-953 Sacavem (Portugal); Coutinho, J.; Macas, B.; Almeida, A.S. [INRB/INIA-Elvas, National Institute of Biological Resources, Est. Gil Vaz, 7350-228 Elvas (Portugal)

    2011-11-15

    The deficiency of essential micronutrients and excess of toxic metals in cereals, an important food items for human nutrition, can cause public health risk. Therefore, before their consumption and adoption of soil supplementation, concentrations of essential micronutrients and metals in cereals should be monitored. This study collected soil and two varieties of wheat samples-Triticum aestivum L. (Jordao/bread wheat), and Triticum durum L. (Marialva/durum wheat) from Elvas area, Portugal and analyzed concentrations of As, Cr, Co, Fe, K, Na, Rb and Zn using Instrumental Neutron Activation Analysis (INAA) to focus on the risk of adverse public health issues. The low variability and moderate concentrations of metals in soils indicated a lower significant effect of environmental input on metal concentrations in agricultural soils. The Cr and Fe concentrations in soils that ranged from 93-117 and 26,400-31,300 mg/kg, respectively, were relatively high, but Zn concentration was very low (below detection limit <22 mg/kg) indicating that soils should be supplemented with Zn during cultivation. The concentrations of metals in roots and straw of both varieties of wheat decreased in the order of K>Fe>Na>Zn>Cr>Rb>As>Co. Concentrations of As, Co and Cr in root, straw and spike of both varieties were higher than the permissible limits with exception of a few samples. The concentrations of Zn in root, straw and spike were relatively low (4-30 mg/kg) indicating the deficiency of an essential micronutrient Zn in wheat cultivated in Portugal. The elemental transfer from soil to plant decreases with increasing growth of the plant. The concentrations of various metals in different parts of wheat followed the order: Root>Straw>Spike. A few root, straw and spike samples showed enrichment of metals, but the majority of the samples showed no enrichment. Potassium is enriched in all samples of root, straw and spike for both varieties of wheat. Relatively to the seed used for cultivation

  4. Estimation of track registration efficiency in solution medium and study of gamma irradiation effects on the bulk-etch rate and the activation energy for bulk etching of CR-39 (DOP) Solid State Nuclear Track Detector

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2010-01-01

    The fission track registration efficiency of diethylene glycol bis allyl carbonate (dioctyl phthalate doped) (CR-39 (DOP)) solid state nuclear track detector (SSNTD) in solution medium (K wet ) has been experimentally determined and is found to be (9.7 ± 0.5).10 -4 cm. This is in good agreement with the values of other SSNTDs. The gamma irradiation effects in the dose range of 50.0-220.0 kGy on the bulk etch rate, V b and the activation energy for bulk etching, E of this solid state nuclear track detector (SSNTD) have also been studied. It is observed that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation

  5. Effect of sintering pressure on structure and magnetic properties of Zn0.99Ni0.01O bulk samples synthesized under different pressures

    International Nuclear Information System (INIS)

    Wang, Yongqiang; Yuan, Chaosheng; Su, Lei; Wang, Zheng; Hao, Junhong; Ren, Yufen

    2015-01-01

    A series of Zn 0.99 Ni 0.01 O bulk samples were prepared by a coprecipitation method, and then sintered at 600 °C under various pressures from normal pressure(NP) to 3 GPa. The effects of sintering pressure (P S ) on the structure, morphology and magnetic properties of the doping samples were investigated in detail. The XRD and HRTEM results reveal that all samples are of single-phase hexagonal structure. Compared with the sample sintered at normal pressure, the lattice parameters a and c of the samples sintered at high pressures (HP) show a sharply decrease. With the increase of sintering pressure, the particle size gradually increases as well as the particles get closer to each other. At 300 K, the sample sintered at normal pressure shows a superparamagnetic-like behavior, while the samples sintered at high pressures display typical ferromagnetic behaviors. The saturation magnetization of the samples sintered at high pressures is three orders of magnitude larger than that of the one sintered at normal pressure. Our results reveal that an appropriate sintering pressure can tune the magnetic properties of Ni-doped ZnO system by changing the lattice parameters, particle size and inter-particle spacing, which may be helpful to the practical applications. - Highlights: • A series of Zn 0.99 Ni 0.01 O bulk samples were sintered in different pressures. • The lattice constants of the samples sintered at high pressure clearly decrease. • The particle size increases gradually with the increase of sintering pressure. • The samples sintered at different pressures show different magnetic behaviors. • Appropriate sintering pressure can tune the magnetic properties of Zn–Ni–O system

  6. Antioxidant activity of oregano, parsley, and olive mill wastewaters in bulk oils and oil-in-water emulsions enriched in fish oil.

    Science.gov (United States)

    Jimenez-Alvarez, D; Giuffrida, F; Golay, P A; Cotting, C; Lardeau, A; Keely, Brendan J

    2008-08-27

    The antioxidant activity of oregano, parsley, olive mill wastewaters (OMWW), Trolox, and ethylenediaminetetraacetic acid (EDTA) was evaluated in bulk oils and oil-in-water (o/w) emulsions enriched with 5% tuna oil by monitoring the formation of hydroperoxides, hexanal, and t-t-2,4-heptadienal in samples stored at 37 degrees C for 14 days. In bulk oil, the order of antioxidant activity was, in decreasing order (p oregano > parsley > EDTA > Trolox. The antioxidant activity in o/w emulsion followed the same order except that EDTA was as efficient an antioxidant as OMWW. In addition, the total phenolic content, the radical scavenging properties, the reducing capacity, and the iron chelating activity of OMWW, parsley, and oregano extracts were determined by the Folin-Ciocalteau, oxygen radical absorbance capacity, ferric reducing antioxidant power, and iron(II) chelating activity assays, respectively. The antioxidant activity of OMWW, parsley, and oregano in food systems was related to their total phenolic content and radical scavenging capacity but not to their ability to chelate iron in vitro. OMWW was identified as a promising source of antioxidants to retard lipid oxidation in fish oil-enriched food products.

  7. High performance liquid chromatography for simultaneous determination of xipamide, triamterene and hydrochlorothiazide in bulk drug samples and dosage forms.

    Science.gov (United States)

    Abd El-Hay, Soad S; Hashem, Hisham; Gouda, Ayman A

    2016-03-01

    A novel, simple and robust high-performance liquid chromatography (HPLC) method was developed and validated for simultaneous determination of xipamide (XIP), triamterene (TRI) and hydrochlorothiazide (HCT) in their bulk powders and dosage forms. Chromatographic separation was carried out in less than two minutes. The separation was performed on a RP C-18 stationary phase with an isocratic elution system consisting of 0.03 mol L(-1) orthophosphoric acid (pH 2.3) and acetonitrile (ACN) as the mobile phase in the ratio of 50:50, at 2.0 mL min(-1) flow rate at room temperature. Detection was performed at 220 nm. Validation was performed concerning system suitability, limits of detection and quantitation, accuracy, precision, linearity and robustness. Calibration curves were rectilinear over the range of 0.195-100 μg mL(-1) for all the drugs studied. Recovery values were 99.9, 99.6 and 99.0 % for XIP, TRI and HCT, respectively. The method was applied to simultaneous determination of the studied analytes in their pharmaceutical dosage forms.

  8. Sample collection and sample analysis plan in support of the 105-C/190-C concrete and soil sampling activities

    International Nuclear Information System (INIS)

    Marske, S.G.

    1996-07-01

    This sampling and analysis plan describes the sample collection and sample analysis in support of the 105-C water tunnels and 190-C main pumphouse concrete and soil sampling activities. These analytical data will be used to identify the radiological contamination and presence of hazardous materials to support the decontamination and disposal activities

  9. Gamma-ray analysis for U, Th and K on bulk cutting samples from deep wells in the Danish Subbasin and the North German Basin

    International Nuclear Information System (INIS)

    Lovborg, L.

    1987-07-01

    A total of 1329 bulk cutting samples from deep wells in Denmark were analysed for U, Th and K by laboratory gamma-ray analysis. Contamination of the samples by drilling mud additives, mud solids and fall down was studied by means of a wash down experiment and by comparison with the total gamma-ray response from wireline logging. It is concluded that the inorganic geochemistry on bulk cutting samples must be applied with great caution. The data are useful for geochemical characterization of well sections and for regional geochemical correlation. Radioelement abundance logs and radioelement ratio logs are presented from 3 wells in the Danish Subbasin and 2 wells in the North German Basin. The radioelement geochemistry is discussed for the successive lithostratigraphical units and a reference radioelement profile is established for the central part of the Danish Subbasin. Finally, a model describing the relationship between common lithofacies and their U content and Th/U ratio is suggested. The model deliniates the depositional environment and the relative distances to the provenance areas. It is concluded that: (1) Uranium is mobile during deposition, but since then it is fixed by stable mineral phases at depth; (2) Thorium reflects source area characteristics and that any available ions are readily adsorbed by clay minerals. Thorium anomalies may thus serve as lithostratigraphical markers; (3) Potassium occurs in unstable rock forming mineral phases. The present distribution is controlled not only by the clastic mineral assemblage, but also by the diagenetic processes through geologic time

  10. Unlocking the Electrocatalytic Activity of Antimony for CO2 Reduction by Two-Dimensional Engineering of the Bulk Material.

    Science.gov (United States)

    Li, Fengwang; Xue, Mianqi; Li, Jiezhen; Ma, Xinlei; Chen, Lu; Zhang, Xueji; MacFarlane, Douglas R; Zhang, Jie

    2017-11-13

    Two-dimensional (2D) materials are known to be useful in catalysis. Engineering 3D bulk materials into the 2D form can enhance the exposure of the active edge sites, which are believed to be the origin of the high catalytic activity. Reported herein is the production of 2D "few-layer" antimony (Sb) nanosheets by cathodic exfoliation. Application of this 2D engineering method turns Sb, an inactive material for CO 2 reduction in its bulk form, into an active 2D electrocatalyst for reduction of CO 2 to formate with high efficiency. The high activity is attributed to the exposure of a large number of catalytically active edge sites. Moreover, this cathodic exfoliation process can be coupled with the anodic exfoliation of graphite in a single-compartment cell for in situ production of a few-layer Sb nanosheets and graphene composite. The observed increased activity of this composite is attributed to the strong electronic interaction between graphene and Sb. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Analytical solutions to sampling effects in drop size distribution measurements during stationary rainfall: Estimation of bulk rainfall variables

    NARCIS (Netherlands)

    Uijlenhoet, R.; Porrà, J.M.; Sempere Torres, D.; Creutin, J.D.

    2006-01-01

    A stochastic model of the microstructure of rainfall is used to derive explicit expressions for the magnitude of the sampling fluctuations in rainfall properties estimated from raindrop size measurements in stationary rainfall. The model is a marked point process, in which the points represent the

  12. Pilot Control of Viscous Bulking in the Activated Sludge Treatment of Industrial Effluent from Soft Drink Plants

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Esfahani

    2007-06-01

    Full Text Available Viscous bulking is a typical problem arising in activated sludge facilities treating effluent from soft drink plants. The drawbacks associated with this phenomenon include increased effluent organic loading and undesirable sludge settlement. In order to investigate this phenomenon, a soft drink factory was selected as a pilot plant for a case study (where metal tanks were used as a biological selector, an aeration basin, and a clarifier. The study shows that the major causes of viscous bulking are high organic loading and undesirable ratio of monovalent to divalent cations. In the biological selector (with a retention time of 20 hours, while the organic load in the influent to the aeration basin decreased by about 50%, with an impact on reduced viscous bulking, pH value decreased from 12 to 6.5 due to fatty acids production. Adjustment of Na/Ca ratio improved bacterial surface hydrophobicity and prevented degradation of biological flocs. This resulted in improved sludge settleability. Application of this method improved sludge settling, made flocs stronger, and reduced effluent organic load (COD to less than 150 mg/l, indicating stability of the system.

  13. The effect of surface-bulk potential difference on the kinetics of intercalation in core-shell active cathode particles

    Science.gov (United States)

    Kazemiabnavi, Saeed; Malik, Rahul; Orvananos, Bernardo; Abdellahi, Aziz; Ceder, Gerbrand; Thornton, Katsuyo

    2018-04-01

    Surface modification of active cathode particles is commonly observed in battery research as either a surface phase evolving during the cycling process, or intentionally engineered to improve capacity retention, rate capability, and/or thermal stability of the cathode material. Here, a continuum-scale model is developed to simulate the galvanostatic charge/discharge of a cathode particle with core-shell heterostructure. The particle is assumed to be comprised of a core material encapsulated by a thin layer of a second phase that has a different open-circuit voltage. The effect of the potential difference between the surface and bulk phases (Ω) on the kinetics of lithium intercalation and the galvanostatic charge/discharge profiles is studied at different values of Ω, C-rates, and exchange current densities. The difference between the Li chemical potential in the surface and bulk phases of the cathode particle results in a concentration difference between these two phases. This leads to a charge/discharge asymmetry in the galvanostatic voltage profiles, causing a decrease in the accessible capacity of the particle. These effects are more significant at higher magnitudes of surface-bulk potential difference. The proposed model provides detailed insight into the kinetics and voltage behavior of the intercalation/de-intercalation processes in core-shell heterostructure cathode particles.

  14. Sample classroom activities based on climate science

    Science.gov (United States)

    Miler, T.

    2009-09-01

    We present several activities developed for the middle school education based on a climate science. The first activity was designed to teach about the ocean acidification. A simple experiment can prove that absorption of CO2 in water increases its acidity. A liquid pH indicator is suitable for the demonstration in a classroom. The second activity uses data containing coordinates of a hurricane position. Pupils draw a path of a hurricane eye in a tracking chart (map of the Atlantic ocean). They calculate an average speed of the hurricane, investigate its direction and intensity development. The third activity uses pictures of the Arctic ocean on September when ice extend is usually the lowest. Students measure the ice extend for several years using a square grid printed on a plastic foil. Then they plot a graph and discuss the results. All these activities can be used to improve the natural science education and increase the climate change literacy.

  15. The effect of solvent on the morphology of an inkjet printed active layer of bulk heterojunction solar cells

    International Nuclear Information System (INIS)

    Fauzia, Vivi; Umar, Akrajas Ali; Salleh, Muhamad Mat; Yahaya, Muhammad

    2011-01-01

    Bulk heterojunction organic solar cells were fabricated by sandwiching the active layer between indium tin oxide (ITO) and Al electrodes. The active layer used was a blend of poly(3-octylthiophene-2,5-diyl) (P3OT) as the electron donor and (6,6)-phenyl C 71 butyric acid methyl ester (PC 71 BM) as the electron acceptor. The active layer thin films were deposited by an inkjet printing technique. Prior to deposition of the thin films, the active materials were blended in three different solvents. The printed films were annealed at three different temperatures. It was found that the selection of the appropriate solvent and annealing treatment significantly influences the printing process, the morphology of the printed film and subsequently the performance of the solar cell devices

  16. STATUS and DIRECTION OF THE BULK VITRIFICATION PROGRAM FOR THE SUPPLEMENTAL TREATMENT OF LOW ACTIVITY TANK WASTE AT HANFORD

    International Nuclear Information System (INIS)

    RAYMOND, R.E.

    2005-01-01

    The DOE Office of River Protection (ORP) is managing a program at the Hanford site that will retrieve and treat more than 200 million liters (53 million gal.) of radioactive waste stored in underground storage tanks. The waste was generated over the past 50 years as part of the nation's defense programs. The project baseline calls for the waste to be retrieved from the tanks and partitioned to separate the highly radioactive constituents from the large volumes of chemical waste. These highly radioactive components will be vitrified into glass logs in the Waste Treatment Plant (WTP), temporarily stored on the Hanford Site, and ultimately disposed of as high-level waste in the offsite national repository. The less radioactive chemical waste, referred to as low-activity waste (LAW), is also planned to be vitrified by the WTP, and then disposed of in approved onsite trenches. However, additional treatment capacity is required in order to complete the pretreatment and immobilization of the tank waste by 2028, which represents a Tri-Party Agreement milestone. To help ensure that the treatment milestones will be met, the Supplemental Treatment Program was undertaken. The program, managed by CH2M HILL Hanford Group, Inc., involves several sub-projects each intended to supplement part of the treatment of waste being designed into the WTP. This includes the testing, evaluation, design, and deployment of supplemental LAW treatment and immobilization technologies, retrieval and treatment of mixed TRU waste stored in the Hanford Tanks, and supplemental pre-treatment. Applying one or more supplemental treatment technologies to the LAW has several advantages, including providing additional processing capacity, reducing the planned loading on the WTP, and reducing the need for double-shell tank space for interim storage of LAW. In fiscal year 2003, three potential supplemental treatment technologies were evaluated including grout, steam reforming and bulk vitrification using AMEC

  17. Gamma-ray analysis for U, TH and K on bulk cutting samples from deep wells in the Danish subbasin and the North German basin

    International Nuclear Information System (INIS)

    Leth Nielsen, B.; Loevborg, L.; Soerensen, P.; Mose, E.

    1987-04-01

    A total of 1329 bulk cutting samples from deep wells in Denmark were analysed for U, Th and K by laboratory gamma-ray analysis. Contamination of the samples by drilling mud additives, mud solids and fall down was studied by means of a wash down experiment and by comparison with the total gamma-ray response from wire-line logging. It is concluded that the inorganic geochemistry on bulk cutting samples must be applied with great caution. The data are useful for geochemical characterization of well sections and for regional geochemical correlation. Radioelement abundance logs and radioelement ratio logs are presented from 3 wells in the Danish Subbasin and 2 wells in the North German Basin. The radioelement geochemistry is discussed for the successive lithostratigraphical units and a reference radio element profile is established for the central part of the Danish Subbasin. Finally, a model describing the relationship between common lithofacies and their U content and Th/U ratio is suggested. The model deliniates the depositional environment and the relative distances to the provenance areas. It is concluded that 1) Uranium is mobile during deposition, but since then it is fixed by stable mineral phases at depth. 2) Thorium reflects source area characteristics and that any available ions are readily adsorped by clay minerals. Thorium anomalies may thus serve as lithostratigraphical markers. 3) Potassium occurs in unstable rock forming mineral phases. The present distribution is controlled not only by the clastic mineral assemblage, but also by the diagenetic processes through geologic time. 33 refs. (author)

  18. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    KAUST Repository

    Maeng, Sungkyu; Sharma, Saroj K.; Abel, Chol D T; Magic-Knezev, Aleksandra; Song, Kyungguen; Amy, Gary L.

    2012-01-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR

  19. DESIGN OF THE DEMOSNTRATION BULK VITRIFICATION SYSTEM FOR THE SUPPLEMENTAL TREATMENT OF LOW ACTIVITY TANK WASTE AT HANFORD

    International Nuclear Information System (INIS)

    VAN BEEK JE

    2008-01-01

    In June 2004, the Demonstration Bulk Vitrification System (DBVS) was initiated with the intent to design, construct, and operate a full-scale bulk vitrification pilot-plant to treat low-activity tank waste from Hanford Tank 241-S-109. The DBVS facility uses In-Container Vitrification(trademark) (ICV(trademark)) at the core of the treatment process. The basic process steps combine liquid low-activity waste (LAW) and glassformers; dry the mixture; and then vitrify the mixture in a batch feed-while-melt process in a refractory lined steel container. Off-gases are processed through a state-of-the-art air pollution control system including sintered-metal filtration, thermal oxidation, acid gas scrubbing, and high-efficiency particulate air (HEPA) and high-efficiency gas adsorber (HEGA) filtration. Testing has focused on development and validation of the waste dryer, ICV, and sintered-metal filters (SMFs) equipment, operations enhancements, and glass formulation. With a parallel testing and design process, testing has allowed improvements to the DBVS equipment configuration and operating methodology, since its original inception. Design improvements include optimization of refractory panels in the ICV, simplifying glassformer addition equipment, increasing the number of waste feed chutes to the ICV, and adding capability for remote clean-out of piping, In addition, the U.S. Department of Energy (DOE) has provided an independent review of the entire DBVS process. While the review did not find any fatal flaws, some technical issues were identified that required a re-evaluation of the DBVS design and subsequent changes to the design. A 100 percent design package for the pilot plant will be completed and submitted to DOE for review in early 2008 that incorporates process improvements substantiated through testing and reviews. This paper provides a description of the bulk vitrification process and a discussion of major equipment design changes that have occurred based on full

  20. Quality of bulk tank milk samples from Danish dairy herds based on real-time polymerase chain reaction identification of mastitis pathogens

    DEFF Research Database (Denmark)

    Katholm, Jørgen; Bennedsgaard, T.W.; Koskinen, M.T.

    2012-01-01

    Results of a commercial real-time PCR analysis for 11 mastitis pathogens from bulk tank milk (BTM) samples from all 4,258 Danish dairy herds in November 2009 to January 2010 were compared with somatic cell count (SCC) and total bacteria count (TBC) estimates in BTM. For Streptococcus agalactiae......, Streptococcus dysgalactiae, and Streptococcus uberis, a low real-time PCR cycle threshold (Ct) value (corresponding to high bacterial DNA quantity) was correlated with higher SCC and higher TBC. For Staphylococcus aureus, low Ct values were correlated only with higher SCC. For the environmental mastitis...... pathogens Klebsiella spp., Enterococcus spp., and Escherichia coli, low Ct values had a correlation with higher TBC. Staphylococcus spp. were found in the BTM from all herds, Strep. uberis in 95%, Staph. aureus in 91%, and Strep. dysgalactiae in 86%, whereas E. coli, Klebsiella, and Strep. agalactiae were...

  1. MATHEMATICAL OPTIMIZATION METHODS TO ESTABLISH ACTIVE PHASES ON HETEROGENEOUS CATALYSIS: CASE OF BULK TRANSITION METAL SULPHIDES

    Directory of Open Access Journals (Sweden)

    Iván Machín

    2015-03-01

    Full Text Available This paper presents a set of procedures based on mathematical optimization methods to establish optimal active sulphide phases with higher HDS activity. This paper proposes a list of active phases as a guide for orienting the experimental work in the search of new catalysts that permit optimize the HDS process. Studies in this paper establish Co-S, Cr-S, Nb-S and Ni-S systems have the greatest potential to improve HDS activity.

  2. Vibration-accelerated activation of flow units in a Pd-based bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ning, E-mail: hslining@mail.hust.edu.cn [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Liu, Ze [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Wang, Xinyun [School of Materials Science and Engineering, and State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Meng [Institute of Advanced Wear & Corrosion Resistant and Functional Materials, Jinan University, Guangzhou 510632 (China)

    2017-04-24

    Controlled activation of flow units and in-situ characterization of mechanical properties in metallic glasses are facing challenges thus far. Here, vibrational loading is introduced through nanoscale dynamic mechanical analysis technique to probe vibration-accelerated atomic level flow that plays a crucial role in the mechanical behavior of metallic glasses. The intriguing finding is that high vibrational frequency induces deep indentation depth, prominent pop-in events on load–depth curves and low storage modulus, exhibiting a vibration-facilitated activation of flow units in Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} metallic glass. Theoretical analysis revealed that vibration-moderated activation time-scale accelerate the activation of flow units and responsible for the above scenario.

  3. Microthrix parvicella abundance associates with activated sludge settling velocity and rheology - Quantifying and modelling filamentous bulking

    DEFF Research Database (Denmark)

    Wágner, Dorottya Sarolta; Ramin, Elham; Szabo, Peter

    2015-01-01

    The objective of this work is to identify relevant settling velocity and rheology model parameters and to assess the underlying filamentous microbial community characteristics that can influence the solids mixing and transport in secondary settling tanks. Parameter values for hindered, transient...... and compression settling velocity functions were estimated by carrying out biweekly batch settling tests using a novel column setup through a four-month long measurement campaign. To estimate viscosity model parameters, rheological experiments were carried out on the same sludge sample using a rotational...... viscometer. Quantitative fluorescence in-situ hybridisation (qFISH) analysis, targeting Microthrix parvicella and phylum Chloroflexi, was used. This study finds that M. parvicella - predominantly residing inside the microbial flocs in our samples - can significantly influence secondary settling through...

  4. A Monte Carlo Library Least Square approach in the Neutron Inelastic-scattering and Thermal-capture Analysis (NISTA) process in bulk coal samples

    Science.gov (United States)

    Reyhancan, Iskender Atilla; Ebrahimi, Alborz; Çolak, Üner; Erduran, M. Nizamettin; Angin, Nergis

    2017-01-01

    A new Monte-Carlo Library Least Square (MCLLS) approach for treating non-linear radiation analysis problem in Neutron Inelastic-scattering and Thermal-capture Analysis (NISTA) was developed. 14 MeV neutrons were produced by a neutron generator via the 3H (2H , n) 4He reaction. The prompt gamma ray spectra from bulk samples of seven different materials were measured by a Bismuth Germanate (BGO) gamma detection system. Polyethylene was used as neutron moderator along with iron and lead as neutron and gamma ray shielding, respectively. The gamma detection system was equipped with a list mode data acquisition system which streams spectroscopy data directly to the computer, event-by-event. A GEANT4 simulation toolkit was used for generating the single-element libraries of all the elements of interest. These libraries were then used in a Linear Library Least Square (LLLS) approach with an unknown experimental sample spectrum to fit it with the calculated elemental libraries. GEANT4 simulation results were also used for the selection of the neutron shielding material.

  5. Applicability of neutron activation analysis to geological samples

    Energy Technology Data Exchange (ETDEWEB)

    Ebihara, Mitsuru [Tokyo Metropolitan Univ., Graduate School of Science, Tokyo (Japan)

    2003-03-01

    The applicability of neutron activation analysis (NAA) to geological samples in space is discussed by referring to future space mission programs, by which the extraterrestrial samples are to be delivered to the earth for scientific inspections. It is concluded that both destructive and non-destructive NAA are highly effective in analyzing these samples. (author)

  6. Applicability of neutron activation analysis to geological samples

    International Nuclear Information System (INIS)

    Ebihara, Mitsuru

    2003-01-01

    The applicability of neutron activation analysis (NAA) to geological samples in space is discussed by referring to future space mission programs, by which the extraterrestrial samples are to be delivered to the earth for scientific inspections. It is concluded that both destructive and non-destructive NAA are highly effective in analyzing these samples. (author)

  7. Active learning and adaptive sampling for non-parametric inference

    NARCIS (Netherlands)

    Castro, R.M.

    2007-01-01

    This thesis presents a general discussion of active learning and adaptive sampling. In many practical scenarios it is possible to use information gleaned from previous observations to focus the sampling process, in the spirit of the "twenty-questions" game. As more samples are collected one can

  8. Impact of CH3NH3PbI3-PCBM bulk heterojunction active layer on the photovoltaic performance of perovskite solar cells

    Science.gov (United States)

    Chaudhary, Dhirendra K.; Kumar, Pankaj; Kumar, Lokendra

    2017-10-01

    We report here the impact of CH3NH3PbI3-PCBM bulk heterojunction (BHJ) active layer on the photovoltaic performance of perovskite solar cells. The solar cells were prepared in normal architecture on FTO coated glass substrates with compact TiO2 (c-TiO2) layer on FTO as electron transport layer (ETL) and poly(3-hexylthiophene) (P3HT) as hole transport layer (HTL). For comparison, a few solar cells were also prepared in planar heterojunction structure using CH3NH3PbI3 only as the active layer. The bulk heterojunction CH3NH3PbI3-PCBM active layer exhibited very large crystalline grains of 2-3 μm compared to ∼150 nm only in CH3NH3PbI3 active layer. Larger grains in bulk-heterojunction solar cells resulted in enhanced power conversion efficiency (PCE) through enhancement in all the photovoltaic parameters compared to planar heterojunction solar cells. The bulk-heterojunction solar cells exhibited ∼9.25% PCE with short circuit current density (Jsc) of ∼18.649 mA/cm2, open circuit voltage (Voc) of 0.894 V and Fill Factor (FF) of 0.554. There was ∼36.9% enhancement in the PCE of bulk-heterojunction solar cells compared to that of planar heterojunction solar cells. The larger grains are formed as a result of incorporation on PCBM in the active layer.

  9. Neutron activation analysis for antimetabolites. [in food samples

    Science.gov (United States)

    1973-01-01

    Determination of metal ion contaminants in food samples is studied. A weighed quantity of each sample was digested in a concentrated mixture of nitric, hydrochloric and perchloric acids to affect complete solution of the food products. The samples were diluted with water and the pH adjusted according to the specific analysis performed. The samples were analyzed by neutron activation analysis, polarography, and atomic absorption spectrophotometry. The solid food samples were also analyzed by neutron activation analysis for increased sensitivity and lower levels of detectability. The results are presented in tabular form.

  10. Occurrence and fate of bulk organic matter and pharmaceutically active compounds in managed aquifer recharge: A review

    KAUST Repository

    Maeng, Sungkyu

    2011-05-01

    Managed aquifer recharge (MAR) is a natural water treatment process that induces surface water to flow in response to a hydraulic gradient through soil/sediment and into a vertical or horizontal well. It is a relatively cost-effective, robust and sustainable technology. Detailed characteristics of bulk organic matter and the occurrence and fate of pharmaceutically active compounds (PhACs) during MAR processes such as bank filtration (BF) and artificial recharge (AR) were reviewed. Understanding the fate of bulk organic matter during BF and AR is an essential step in determining pre- and/or post-treatment requirements. Analysis of organic matter characteristics using a suite of analytical tools suggests that there is a preferential removal of non-humic substances during MAR. Different classes of PhACs were found to behave differently during BF and AR. Antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), beta blockers, and steroid hormones generally exhibited good removal efficiencies, especially for compounds having hydrophobic-neutral characteristics. However, anticonvulsants showed a persistent behavior during soil passage. There were also some redox-dependent PhACs. For example, X-ray contrast agents measured, as adsorbable organic iodine (AOI), and sulfamethoxazole (an antibiotic) degraded more favorably under anoxic conditions compared to oxic conditions. Phenazone-type pharmaceuticals (NSAIDs) exhibited better removal under oxic conditions. The redox transition from oxic to anoxic conditions during soil passage can enhance the removal of PhACs that are sensitive to redox conditions. In general, BF and AR can be included in a multi-barrier treatment system for the removal of PhACs. © 2011.

  11. Occurrence and fate of bulk organic matter and pharmaceutically active compounds in managed aquifer recharge: a review.

    Science.gov (United States)

    Maeng, Sung Kyu; Sharma, Saroj K; Lekkerkerker-Teunissen, Karin; Amy, Gary L

    2011-05-01

    Managed aquifer recharge (MAR) is a natural water treatment process that induces surface water to flow in response to a hydraulic gradient through soil/sediment and into a vertical or horizontal well. It is a relatively cost-effective, robust and sustainable technology. Detailed characteristics of bulk organic matter and the occurrence and fate of pharmaceutically active compounds (PhACs) during MAR processes such as bank filtration (BF) and artificial recharge (AR) were reviewed. Understanding the fate of bulk organic matter during BF and AR is an essential step in determining pre- and/or post-treatment requirements. Analysis of organic matter characteristics using a suite of analytical tools suggests that there is a preferential removal of non-humic substances during MAR. Different classes of PhACs were found to behave differently during BF and AR. Antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), beta blockers, and steroid hormones generally exhibited good removal efficiencies, especially for compounds having hydrophobic-neutral characteristics. However, anticonvulsants showed a persistent behavior during soil passage. There were also some redox-dependent PhACs. For example, X-ray contrast agents measured, as adsorbable organic iodine (AOI), and sulfamethoxazole (an antibiotic) degraded more favorably under anoxic conditions compared to oxic conditions. Phenazone-type pharmaceuticals (NSAIDs) exhibited better removal under oxic conditions. The redox transition from oxic to anoxic conditions during soil passage can enhance the removal of PhACs that are sensitive to redox conditions. In general, BF and AR can be included in a multi-barrier treatment system for the removal of PhACs. Copyright © 2011. Published by Elsevier Ltd.

  12. SNS Sample Activation Calculator Flux Recommendations and Validation

    Energy Technology Data Exchange (ETDEWEB)

    McClanahan, Tucker C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Gallmeier, Franz X. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Iverson, Erik B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Lu, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)

    2015-02-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) uses the Sample Activation Calculator (SAC) to calculate the activation of a sample after the sample has been exposed to the neutron beam in one of the SNS beamlines. The SAC webpage takes user inputs (choice of beamline, the mass, composition and area of the sample, irradiation time, decay time, etc.) and calculates the activation for the sample. In recent years, the SAC has been incorporated into the user proposal and sample handling process, and instrument teams and users have noticed discrepancies in the predicted activation of their samples. The Neutronics Analysis Team validated SAC by performing measurements on select beamlines and confirmed the discrepancies seen by the instrument teams and users. The conclusions were that the discrepancies were a result of a combination of faulty neutron flux spectra for the instruments, improper inputs supplied by SAC (1.12), and a mishandling of cross section data in the Sample Activation Program for Easy Use (SAPEU) (1.1.2). This report focuses on the conclusion that the SAPEU (1.1.2) beamline neutron flux spectra have errors and are a significant contributor to the activation discrepancies. The results of the analysis of the SAPEU (1.1.2) flux spectra for all beamlines will be discussed in detail. The recommendations for the implementation of improved neutron flux spectra in SAPEU (1.1.3) are also discussed.

  13. Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

  14. Analysis of atmospheric particulate samples via instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Greenberg, R.R.

    1990-01-01

    Instrumental neutron activation analysis (INAA) is a powerful analytical technique for the elemental characterization of atmospheric particulate samples. It is a true multielement technique with adequate sensitivity to determine 30 to 40 elements in a sample of atmospheric particulate material. Its nondestructive nature allows sample reanalysis by the same or a different analytical technique. In this paper as an example of the applicability of INAA to the study of atmospheric particulate material, a study of the emissions from municipal incinerators is described

  15. An instrumentation for control and measurement of activated mineral samples

    International Nuclear Information System (INIS)

    Skaarup, P.

    1976-01-01

    A description is given of an instrumentation for control of a pneumatic tube system used to transport mineral samples for activation in a reactor and from there to a detector arrangement. A possible content of uranium in the samples can be seen from the radiation measured. The instrumentation includes a PDP-11 computer and a CAMAC crate

  16. Brazilian samples of bee samples pollen: palynological origin, phenolic content, antioxidant properties and antimicrobial activity

    OpenAIRE

    Arruda, Vanilda Aparecida Soares de; Santos, Alexandre V. dos; Figueiredo, Davi; Meira, Sampaio; Estevinho, Leticia M.; Barth, Ortrud M.; Freitas, Alex da Silva de; Almeida-Muradian, Ligia Bicudo

    2012-01-01

    Total phenolic and flavonoids phytochemical concentration was measured in bee pollen samples, Appis Mellifera , as well as their botanical origin, antioxidant activity and antimicrobial activity. Pollen loads were washed with 70% ethanol and identified using a 400x magnification. The content of total polyphenols and flavonoids was measured spectrophotometrically with gallic acid and quercetin as standard. The antioxidant activity was evaluated by the linking capacity of (i)the fre...

  17. A survey of the exposure to Ostertagia ostertagi in dairy cow herds in Europe through the measurement of antibodies in milk samples from the bulk tank.

    Science.gov (United States)

    Forbes, A B; J Vercruysse; Charlier, J

    2008-10-20

    Measurement of antibodies to Ostertagia ostertagi in bulk tank milk (BTM) has value as a diagnostic indicator for potential production losses and anthelmintic treatment responses in dairy herds. Most of the recent data on O. ostertagi antibodies in milk have been generated in Belgium and Canada; the purpose of this study was to determine the range of O. ostertagi antibody levels in several European countries. BTM samples were collected during the autumn of 2005 and 2006 from a total of 1185 dairy herds from dairy farming regions in Denmark, Germany, Ireland, Italy, the Netherlands, Portugal, Spain and the United Kingdom. Antibody titres to O. ostertagi were determined by indirect ELISA and expressed as optical density ratios (ODR). In addition, relationships between ODR and management practices were investigated. For each country the mean ODR and the 25th-75th percentile values were determined. Mean BTM ODR values in herds with access to yards, paddocks and pastures ranged from 0.3 in Italy to 0.6 in Portugal and the UK/Ireland. The BTM ODR values obtained in this study were generally lower than those described in the literature for Belgium, but comparable with those in Canada. Variations between different European countries appeared to reflect different husbandry practices, particularly those related to access to pasture. The association analyses showed correlations between the BTM O. ostertagi ODR, outside access and grazing management, consistent with the publications from Belgium and Canada. When diagnostic values appropriate for different production situations and environments have been further validated, the test will provide an objective, quantitative assessment of the O. ostertagi status of a dairy herd and the possible impact this may have on performance and potential responses to anthelmintic treatment. This represents a significant step forward in evidence-based medicine for dairy veterinarians, advisors and farmers.

  18. Bulk density calculations from prompt gamma ray yield

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Maslehuddin, M.

    2006-01-01

    Full text: The gamma ray yield from a Prompt Gamma ray Neutron Activation Analysis (PGNAA) setup is a linear function of element concentration and neutron flux in a the sample with constant bulk density. If the sample bulk density varies as well, then the element concentration and the neutron flux has a nonlinear correlation with the gamma ray yield [1]. The measurement of gamma ray yield non-linearity from samples and a standard can be used to estimate the bulk density of the samples. In this study the prompt gamma ray yield from Blast Furnace Slag, Fly Ash, Silica Fumes and Superpozz cements samples have been measured as a function of their calcium and silicon concentration using KFUPM accelerator-based PGNAA setup [2]. Due to different bulk densities of the blended cement samples, the measured gamma ray yields have nonlinear correlation with calcium and silicon concentration of the samples. The non-linearity in the yield was observed to increase with gamma rays energy and element concentration. The bulk densities of the cement samples were calculated from ratio of gamma ray yield from blended cement and that from a Portland cement standard. The calculated bulk densities have good agreement with the published data. The result of this study will be presented

  19. Graphene as an active virtually massless top electrode for RF solidly mounted bulk acoustic wave (SMR-BAW) resonators

    Science.gov (United States)

    Knapp, Marius; Hoffmann, René; Lebedev, Vadim; Cimalla, Volker; Ambacher, Oliver

    2018-03-01

    Mechanical and electrical losses induced by an electrode material greatly influence the performance of bulk acoustic wave (BAW) resonators. Graphene as a conducting and virtually massless 2D material is a suitable candidate as an alternative electrode material for BAW resonators which reduces electrode induced mechanical losses. In this publication we show that graphene acts as an active top electrode for solidly mounted BAW resonators (BAW-SMR) at 2.1 GHz resonance frequency. Due to a strong decrease of mass loading and its remarkable electronic properties, graphene demonstrates its ability as an ultrathin conductive layer. In our experiments we used an optimized graphene wet transfer on aluminum nitride-based solidly mounted resonator devices. We achieved more than a triplication of the resonator’s quality factor Q and a resonance frequency close to an ‘unloaded’ resonator without metallization. Our results reveal the direct influence of both, the graphene quality and the graphene contacting via metal structures, on the performance characteristic of a BAW resonator. These findings clearly show the potential of graphene in minimizing mechanical losses due to its virtually massless character. Moreover, they highlight the advantages of graphene and other 2D conductive materials for alternative electrodes in electroacoustic resonators for radio frequency applications.

  20. An organic water-gated ambipolar transistor with a bulk heterojunction active layer for stable and tunable photodetection

    Science.gov (United States)

    Xu, Haihua; Zhu, Qingqing; Wu, Tongyuan; Chen, Wenwen; Zhou, Guodong; Li, Jun; Zhang, Huisheng; Zhao, Ni

    2016-11-01

    Organic water-gated transistors (OWGTs) have emerged as promising sensing architectures for biomedical applications and environmental monitoring due to their ability of in-situ detection of biological substances with high sensitivity and low operation voltage, as well as compatibility with various read-out circuits. Tremendous progress has been made in the development of p-type OWGTs. However, achieving stable n-type operation in OWGTs due to the presence of solvated oxygen in water is still challenging. Here, we report an ambipolar OWGT based on a bulk heterojunction active layer, which exhibits a stable hole and electron transport when exposed to aqueous environment. The device can be used as a photodetector both in the hole and electron accumulation regions to yield a maximum responsivity of 0.87 A W-1. More importantly, the device exhibited stable static and dynamic photodetection even when operated in the n-type mode. These findings bring possibilities for the device to be adopted for future biosensing platforms, which are fully compatible with low-cost and low-power organic complementary circuits.

  1. A retrospective evaluation of a Bovine Herpesvirus-1 (BHV-1) antibody ELISA on bulk-tank milk samples for classification of the BHV-1 status of Danish dairy herds

    DEFF Research Database (Denmark)

    Nylin, Britta; Strøger, Ulla; Rønsholt, Leif

    2000-01-01

    Bulk-tank milk samples analysed in a Bovine Herpesvirus-1 (BHV-1) blocking ELISA are still in use in the Danish BHV-1 programme as a tool to classify dairy herds as BHV-1 infected or BHV-1 free herds. in this retrospective study, we used data from the Danish BHV-1 eradication campaign to evaluate...

  2. Neutron activation analysis of certified samples by the absolute method

    Science.gov (United States)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  3. Radiochemical neutron activation analysis of gold in geochemical samples

    International Nuclear Information System (INIS)

    Zilliacus, R.

    1983-01-01

    A fast method for the radiochemical neutron activation analysis of gold in geochemical samples is described. The method is intended for samples having background concentrations of gold. The method is based on the dissolution of samples with hydrofluoric acid and aqua regia followed by the dissolution of the fluorides with boric acid and hydrochloric acid. Gold is then adsorbed on activated carbon by filtrating the solution through a thin carbon layer. The activity measurements are carried out using a Ge(Li)-detector and a multichannel analyzer. The chemical yields of the separation determined by reirradiation vary between 60 and 90%. The detection limit of the method is 0.2 ng/g gold in rock samples. USGS standard rocks and exploration reference materials are analyzed and the results are presented and compared with literature data. (author)

  4. Approximate determination of efficiency for activity measurements of cylindrical samples

    Energy Technology Data Exchange (ETDEWEB)

    Helbig, W [Nuclear Engineering and Analytics Rossendorf, Inc. (VKTA), Dresden (Germany); Bothe, M [Nuclear Engineering and Analytics Rossendorf, Inc. (VKTA), Dresden (Germany)

    1997-03-01

    Some calibration samples are necessary with the same geometrical parameters but of different materials, containing known activities A homogeniously distributed. Their densities are measured, their mass absorption coefficients may be unknown. These calibration samples are positioned in the counting geometry, for instance directly on the detector. The efficiency function {epsilon}(E) for each sample is gained by measuring the gamma spectra and evaluating all usable gamma energy peaks. From these {epsilon}(E) the common valid {epsilon}{sub geom}(E) will be deduced. For this purpose the functions {epsilon}{sub mu}(E) for these samples have to be established. (orig.)

  5. Distinguishing Between Activated and Non-Activated Eosinophils Using a Microelectrode: Theoretical Investigations of Bulk and Surface Polaritons in Magnetic Multilayers

    Science.gov (United States)

    Lacy, Fred

    In Part I of this dissertation, a whole cell biosensor which can detect the activation state of eosinophils (one of several types of white blood cells) will be developed and tested. This biosensor, which consists of a small gold electrode (50 μm x 50 μm) and a large gold electrode (1.5 cm x 0.5 cm) on a glass substrate, has been fabricated by photolithographic techniques. The eosinophils are known to exhibit different physical properties when they change from the activated state to the non-activated state. Based on some of these property changes, there should be a corresponding change in the measured electrical impedance. In this research, this biosensor will measure the electrical impedance of the eosinophils. This will show that the biosensor can detect the different states of the eosinophils (through the electrical impedance technique). And from these measurements, the different parameters associated with the electrical impedance can be determined. In Part II of this dissertation, a theoretical calculation will be performed in which bulk and surface magnetic polaritons in magnetic materials will be found. A polariton is the coupling of electromagnetic radiation and the elementary excitation of the given material (in our case, a magnetic material). The structure that we will be considering is a periodic semi-infinite material consisting of alternating antiferromagnetic and nonmagnetic layers. An antiferromagnetic material is a material in which individual atoms exhibit magnetic moments, but the overall magnetization of the material is zero because the moments of every other atom are antiparallel. We will use a method known as the transfer matrix technique to find an expression for the dispersion relation of the bulk and surface waves in these materials. Then we will create plots of omega(k) as we vary the geometric configurations of the layers which make-up the magnetic multilayer. We also will calculate the effect of an external magnetic field on these

  6. Determination Of Activity Of Radionuclides In Moss-Soil Sample With Self-Absorption Correction

    International Nuclear Information System (INIS)

    Tran Thien Thanh; Chau Van Tao; Truong Thi Hong Loan; Hoang Duc Tam

    2011-01-01

    Hyper Pure Germanium (HPGe) spectrometer system is a very powerful tool for radioactivity measurements. The systematic uncertainty in the full energy peak efficiency is due to the differences between the matrix (density and chemical composition) of the reference and the other bulk samples. For getting precision from the gamma spectrum analysis, the absorbed correction in the sample should be considered. For gamma spectral analysis, a correction for absorption effects in sample should be considered, especially for bulk samples. The results were presented and discussed in this paper. (author)

  7. Bulk Heterojunction Solar Cell with Nitrogen-Doped Carbon Nanotubes in the Active Layer: Effect of Nanocomposite Synthesis Technique on Photovoltaic Properties

    Directory of Open Access Journals (Sweden)

    Godfrey Keru

    2015-05-01

    Full Text Available Nanocomposites of poly(3-hexylthiophene (P3HT and nitrogen-doped carbon nanotubes (N-CNTs have been synthesized by two methods; specifically, direct solution mixing and in situ polymerization. The nanocomposites were characterized by means of transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray dispersive spectroscopy, UV-Vis spectrophotometry, photoluminescence spectrophotometry (PL, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, thermogravimetric analysis, and dispersive surface energy analysis. The nanocomposites were used in the active layer of a bulk heterojunction organic solar cell with the composition ITO/PEDOT:PSS/P3HT:N-CNTS:PCBM/LiF/Al. TEM and SEM analysis showed that the polymer successfully wrapped the N-CNTs. FTIR results indicated good π-π interaction within the nanocomposite synthesized by in situ polymerization as opposed to samples made by direct solution mixing. Dispersive surface energies of the N-CNTs and nanocomposites supported the fact that polymer covered the N-CNTs well. J-V analysis show that good devices were formed from the two nanocomposites, however, the in situ polymerization nanocomposite showed better photovoltaic characteristics.

  8. Lake and bulk sampling chemistry, NADP, and IMPROVE air quality data analysis on the Bridger-Teton National Forest (USFS Region 4)

    Science.gov (United States)

    Jill Grenon; Terry Svalberg; Ted Porwoll; Mark Story

    2010-01-01

    Air quality monitoring data from several programs in and around the Bridger-Teton (B-T) National Forest - National Atmospheric Deposition Program (NADP), longterm lake monitoring, long-term bulk precipitation monitoring (both snow and rain), and Interagency Monitoring of Protected Visual Environments (IMPROVE) - were analyzed in this report. Trends were analyzed using...

  9. Bulk analysis using nuclear techniques

    International Nuclear Information System (INIS)

    Borsaru, M.; Holmes, R.J.; Mathew, P.J.

    1983-01-01

    Bulk analysis techniques developed for the mining industry are reviewed. Using penetrating neutron and #betta#-radiations, measurements are obtained directly from a large volume of sample (3-30 kg) #betta#-techniques were used to determine the grade of iron ore and to detect shale on conveyor belts. Thermal neutron irradiation was developed for the simultaneous determination of iron and aluminium in iron ore on a conveyor belt. Thermal-neutron activation analysis includes the determination of alumina in bauxite, and manganese and alumina in manganese ore. Fast neutron activation analysis is used to determine silicon in iron ores, and alumina and silica in bauxite. Fast and thermal neutron activation has been used to determine the soil in shredded sugar cane. (U.K.)

  10. Neutron activation analysis for environmental sample in Thailand

    International Nuclear Information System (INIS)

    Busamongkol, Arporn; Nouchpramool, Sunun; Bunprapob, Supamatthree; Sumitra, Tatchai

    2003-01-01

    Neutron Activation Analysis has been applied for the trace elements analysis in environmental samples. Thirty three samples of airborne particulate were collected every week at Ongkharak Nuclear Research Center (ONRC) during the period of June 1998 to March 1999. The Ti, I, Mg, Na, V, K, Cl, Al, Mn, Ca, As, Sm, Sb, Br, La, Ce, Th, Cr, Cs, Sc, Rb, Fe, Zn and Co were analyzed by Neutron Activation Analysis utilizing 2 MW TRIGA MARK III research reactor. The certified reference materials 1632a and 1633a from National Bureau of Standard were select as standard. (author)

  11. Automatic sample changer for neutron activation analysis at CDTN, Brazil

    International Nuclear Information System (INIS)

    Aimore Dutra Neto; Oliveira Pelaes, Ana Clara; Jacimovic, Radojko

    2018-01-01

    An automatic sample changer was recently developed and installed in the Neutron Activation Analysis (NAA) Laboratory. The certified reference material BCR-320R, Channel Sediment, was analysed in order to verify the reliability of the results obtained by NAA, k 0 -standardisation method, using this automatic system during the gamma-ray measurement step. The results were compared to those manually obtained. The values pointed out that the automatic sample changer is working properly. This changer will increase the productiveness of the neutron activation technique applied at Nuclear Technology Development Centre, CDTN/CNEN expanding its competitiveness as an analytical technique in relation to other techniques. (author)

  12. Development of Large Sample Neutron Activation Technique for New Applications in Thailand

    International Nuclear Information System (INIS)

    Laoharojanaphand, S.; Tippayakul, C.; Wonglee, S.; Channuie, J.

    2018-01-01

    The development of the Large Sample Neutron Activation Analysis (LSNAA) in Thailand is presented in this paper. The technique had been firstly developed with rice sample as the test subject. The Thai Research Reactor-1/Modification 1 (TRR-1/M1) was used as the neutron source. The first step was to select and characterize an appropriate irradiation facility for the research. An out-core irradiation facility (A4 position) was first attempted. The results performed with the A4 facility were then used as guides for the subsequent experiments with the thermal column facility. The characterization of the thermal column was performed with Cu-wire to determine spatial distribution without and with rice sample. The flux depression without rice sample was observed to be less than 30% while the flux depression with rice sample increased to within 60%. The flux monitors internal to the rice sample were used to determine average flux over the rice sample. The gamma selfshielding effect during gamma measurement was corrected using the Monte Carlo simulation. The ratio between the efficiencies of the volume source and the point source for each energy point was calculated by the MCNPX code. The research team adopted the k0-NAA methodology to calculate the element concentration in the research. The k0-NAA program which developed by IAEA was set up to simulate the conditions of the irradiation and measurement facilities used in this research. The element concentrations in the bulk rice sample were then calculated taking into account the flux depression and gamma efficiency corrections. At the moment, the results still show large discrepancies with the reference values. However, more research on the validation will be performed to identify sources of errors. Moreover, this LS-NAA technique was introduced for the activation analysis of the IAEA archaeological mock-up. The results are provided in this report. (author)

  13. Sampling frequency affects ActiGraph activity counts

    DEFF Research Database (Denmark)

    Brønd, Jan Christian; Arvidsson, Daniel

    that is normally performed at frequencies higher than 2.5 Hz. With the ActiGraph model GT3X one has the option to select sample frequency from 30 to 100 Hz. This study investigated the effect of the sampling frequency on the ouput of the bandpass filter.Methods: A synthetic frequency sweep of 0-15 Hz was generated...... in Matlab and sampled at frequencies of 30-100 Hz. Also, acceleration signals during indoor walking and running were sampled at 30 Hz using the ActiGraph GT3X and resampled in Matlab to frequencies of 40-100 Hz. All data was processed with the ActiLife software.Results: Acceleration frequencies between 5......-15 Hz escaped the bandpass filter when sampled at 40, 50, 70, 80 and 100 Hz, while this was not the case when sampled at 30, 60 and 90 Hz. During the ambulatory activities this artifact resultet in different activity count output from the ActiLife software with different sampling frequency...

  14. Improved mesh based photon sampling techniques for neutron activation analysis

    International Nuclear Information System (INIS)

    Relson, E.; Wilson, P. P. H.; Biondo, E. D.

    2013-01-01

    The design of fusion power systems requires analysis of neutron activation of large, complex volumes, and the resulting particles emitted from these volumes. Structured mesh-based discretization of these problems allows for improved modeling in these activation analysis problems. Finer discretization of these problems results in large computational costs, which drives the investigation of more efficient methods. Within an ad hoc subroutine of the Monte Carlo transport code MCNP, we implement sampling of voxels and photon energies for volumetric sources using the alias method. The alias method enables efficient sampling of a discrete probability distribution, and operates in 0(1) time, whereas the simpler direct discrete method requires 0(log(n)) time. By using the alias method, voxel sampling becomes a viable alternative to sampling space with the 0(1) approach of uniformly sampling the problem volume. Additionally, with voxel sampling it is straightforward to introduce biasing of volumetric sources, and we implement this biasing of voxels as an additional variance reduction technique that can be applied. We verify our implementation and compare the alias method, with and without biasing, to direct discrete sampling of voxels, and to uniform sampling. We study the behavior of source biasing in a second set of tests and find trends between improvements and source shape, material, and material density. Overall, however, the magnitude of improvements from source biasing appears to be limited. Future work will benefit from the implementation of efficient voxel sampling - particularly with conformal unstructured meshes where the uniform sampling approach cannot be applied. (authors)

  15. Comparisons of Soil Properties, Enzyme Activities and Microbial Communities in Heavy Metal Contaminated Bulk and Rhizosphere Soils of Robinia pseudoacacia L. in the Northern Foot of Qinling Mountain

    Directory of Open Access Journals (Sweden)

    Yurong Yang

    2017-11-01

    Full Text Available The toxic effects of heavy metal (HM contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem. The present study was conducted to evaluate the rhizosphere effect on soil properties, enzyme activities and bacterial communities associated with Robinia pseudoacacia L. along a HM contamination gradient. Soil organic matter (SOM, available nitrogen (AN and phosphorus (AP contents were significantly higher in rhizosphere soil than those in bulk soil at HM contaminated sites (p < 0.05. Compared to bulk soil, activities of four soil enzymes indicative of C cycle (β-glucosidase, N cycle (protease, urease and P cycle (alkaline phosphatase in rhizosphere soil across all study sites increased by 47.5%, 64.1%, 52.9% and 103.8%, respectively. Quantitative PCR (qPCR and restriction fragment length polymorphism (RFLP were used to determine the relative abundance, composition and diversity of bacteria in both bulk and rhizosphere soils, respectively. The copy number of bacterial 16S rRNA gene in bulk soil was significantly lower than that in rhizosphere soil (p < 0.05, and it had significantly negative correlations with total/DTPA-extractable Pb concentrations (p < 0.01. Alphaproteobacteria, Gammaproteobacteria and Firmicutes were the most dominant groups of bacteria at different study sites. The bacterial diversity index of Species richness (S and Margalef (dMa were significantly higher in rhizosphere soil compared with those in bulk soil, although no difference could be found in Simpson index (D between bulk and rhizosphere soils (p > 0.05. Redundancy analysis (RDA results showed that soil pH, EC, SOM and total/DTPA-extractable Pb concentrations were the most important variables affecting relative abundance, composition and diversity of bacteria (p < 0

  16. Phosphorus analysis in milk samples by neutron activation analysis method

    International Nuclear Information System (INIS)

    Oliveira, R.M. de; Cunha, I.I.L.

    1991-01-01

    The determination of phosphorus in milk samples by instrumental thermal neutron activation analysis is described. The procedure involves a short irradiation in a nuclear reactor and measurement of the beta radiation emitted by phosphorus - 32 after a suitable decay period. The sources of error were studied and the established method was applied to standard reference materials of known phosphorus content. (author)

  17. Quantification and antibacterial activity of flavonoids in coffee samples

    African Journals Online (AJOL)

    Background: Flavonoids are the phenolic substances widely found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and coffee. Methodology: In the current study quantity of flavonoids and antibacterial activities were determined in different coffee samples namely Nescafe classic, Nescafe gold, Nescafe martina, ...

  18. Performance of an active well coincidence counter for HEU samples

    International Nuclear Information System (INIS)

    Ferrari, Francesca; Peerani, Paolo

    2010-01-01

    Neutron coincidence counting is the reference NDA technique used in nuclear safeguards to measure the mass of nuclear material in samples. For high-enriched uranium (HEU) samples active neutron interrogation is generally performed and the most common device used by nuclear inspectors is the Active Well Coincidence Counter (AWCC). Within her master thesis at the Polytechnic of Milan, the first author performed an intensive study on the characteristics and performances of the AWCC in order to assess the 235 U mass in HEU oxide samples at the PERLA laboratory of JRC. The work has been summarised in this paper that starts with the optimisation of the use of AWCC for nuclear safeguards, describing the calibration procedure, reporting results of a series of verification measurements, summarising the performances that can be obtained with this instruments during inspections at fuel production plants and concluding with the discussion of uncertainties related to these measurements.

  19. Analysis of industrial coke samples by activation with cyclotron protons

    International Nuclear Information System (INIS)

    Chaudhri, M.A.; Lee, M.M.; Spicer, B.M.

    1982-01-01

    A Melbourne Petrochemical Company was experiencing excessive coke formation in its ''cracking furnaces'', which was causing unnecessary stoppage of production and wastage of energy due to additional insulation. In order to investigate the possible causes of this excessive coke formation, we analyzed various coke samples and other coke-like materials obtained from these furnaces by activation with cyclotron-protons. Our results showed that, out of the two suspected coke promoters As and Sb whose small concentration in feed would produce greatly accelerated coke formation, As could not be detected in any of the eight samples investigated, while Sb was present in only one sample. However, we did observe Ca, Cr and Fe in all the samples, with surprisingly high concentrations in some of them. It has, therefore, been suggested that Ca, and perhaps Cr and Fe, but not As or Sb, could have been responsible for the excessive coke formation in the ''cracking furnaces''

  20. National comparison on volume sample activity measurement methods

    International Nuclear Information System (INIS)

    Sahagia, M.; Grigorescu, E.L.; Popescu, C.; Razdolescu, C.

    1992-01-01

    A national comparison on volume sample activity measurements methods may be regarded as a step toward accomplishing the traceability of the environmental and food chain activity measurements to national standards. For this purpose, the Radionuclide Metrology Laboratory has distributed 137 Cs and 134 Cs water-equivalent solid standard sources to 24 laboratories having responsibilities in this matter. Every laboratory has to measure the activity of the received source(s) by using its own standards, equipment and methods and report the obtained results to the organizer. The 'measured activities' will be compared with the 'true activities'. A final report will be issued, which plans to evaluate the national level of precision of such measurements and give some suggestions for improvement. (Author)

  1. Multielemental neutron activation analysis of some egyptian cement samples

    International Nuclear Information System (INIS)

    Eissa, E.A.; Rofail, N.B.; Abdel-Basset, N.; Soroor, A.; Hassan, A.M.

    1996-01-01

    Multielemental analysis of normal, Karnak and sea-water cement samples were performed by neutron activation analysis technique using the (ET-R R-1) reactor for sample irradiation. The Data were collected and analysed by means of the (HPGe) detection system and a Pca computer. A total of 23 elements namely, Na, A1, C 1, K, Ca, Sc, Cr, Mn, Fe, Co, Zn, Sr, Ba, La, Sm, Eu, Yb, Lu, Ta, Au, Th and U were identified and analysed with concentrations ranging from 1 ppm upto 62% a comparison between the elemental concentrations of the three cement types is given. 2 tabs

  2. Gross beta activity of the Danube river samples in 2006

    International Nuclear Information System (INIS)

    Tanaskovic, I.; Pantelic, G.; Eremic-Savkovic, M.; Vuletic, V.; Javorina, Lj.; Tanaskovic, I.)

    2007-01-01

    Our paper presents the results of radioactivity control of the Danube samples on Serbian (Bezdan left coast) in 2006. The measurements were carried out by low-phone proportional gas alpha beta counter PIC-WPC-9550. Efficiency for activity was 47%. The results of measurements of gross beta activity (water, sediment, algae and fish) reveal that the values are at the same level as they were before the Paks Nuclear power plant started running. Our results of measurements correlate well with the results of Hungarian part. (author) [sr

  3. Enhanced activities of organically bound tritium in biota samples.

    Science.gov (United States)

    Svetlik, I; Fejgl, M; Malátová, I; Tomaskova, L

    2014-11-01

    A pilot study aimed on possible occurrence of elevated activity of non-exchangable organically bound tritium (NE-OBT) in biota was performed. The first results showed a significant surplus of NE-OBT activity in biota of the valley of Mohelno reservoir and Jihlava river. The liquid releases of HTO from the nuclear power plant Dukovany is the source of tritium in this area. This area can be a source of various types of natural samples for future studies of tritium pathways. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Semiautomatic exchanger of samples for carry out neutron activation analysis

    International Nuclear Information System (INIS)

    Aguilar H, F.; Quintana C, G.; Torres R, C. E.; Mejia J, J. O.

    2015-09-01

    In this paper the design methodology and implementation of a semiautomatic exchanger of samples for the Analysis Laboratory by Neutron Activation of the Reactor department is presented. Taking into account the antecedents, the necessities of improvement are described, as well as the equipment that previously contained the Laboratory. The project of the semiautomatic exchanger of samples was developed at Instituto Nacional de Investigaciones Nucleares, with its own technology to increase independence from commercial equipment. Each element of the semiautomatic exchanger of samples is described both in the design phase as construction. The achieved results are positive and encouraging for the fulfillment of the proposed objective that is to increase the capacity of the Laboratory. (Author)

  5. Active Fault Diagnosis in Sampled-data Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2015-01-01

    The focus in this paper is on active fault diagnosis (AFD) in closed-loop sampleddata systems. Applying the same AFD architecture as for continuous-time systems does not directly result in the same set of closed-loop matrix transfer functions. For continuous-time systems, the LFT (linear fractional...... transformation) structure in the connection between the parametric faults and the matrix transfer function (also known as the fault signature matrix) applied for AFD is not directly preserved for sampled-data system. As a consequence of this, the AFD methods cannot directly be applied for sampled-data systems....... Two methods are considered in this paper to handle the fault signature matrix for sampled-data systems such that standard AFD methods can be applied. The first method is based on a discretization of the system such that the LFT structure is preserved resulting in the same LFT structure in the fault...

  6. Less is more: Sampling chemical space with active learning

    Science.gov (United States)

    Smith, Justin S.; Nebgen, Ben; Lubbers, Nicholas; Isayev, Olexandr; Roitberg, Adrian E.

    2018-06-01

    The development of accurate and transferable machine learning (ML) potentials for predicting molecular energetics is a challenging task. The process of data generation to train such ML potentials is a task neither well understood nor researched in detail. In this work, we present a fully automated approach for the generation of datasets with the intent of training universal ML potentials. It is based on the concept of active learning (AL) via Query by Committee (QBC), which uses the disagreement between an ensemble of ML potentials to infer the reliability of the ensemble's prediction. QBC allows the presented AL algorithm to automatically sample regions of chemical space where the ML potential fails to accurately predict the potential energy. AL improves the overall fitness of ANAKIN-ME (ANI) deep learning potentials in rigorous test cases by mitigating human biases in deciding what new training data to use. AL also reduces the training set size to a fraction of the data required when using naive random sampling techniques. To provide validation of our AL approach, we develop the COmprehensive Machine-learning Potential (COMP6) benchmark (publicly available on GitHub) which contains a diverse set of organic molecules. Active learning-based ANI potentials outperform the original random sampled ANI-1 potential with only 10% of the data, while the final active learning-based model vastly outperforms ANI-1 on the COMP6 benchmark after training to only 25% of the data. Finally, we show that our proposed AL technique develops a universal ANI potential (ANI-1x) that provides accurate energy and force predictions on the entire COMP6 benchmark. This universal ML potential achieves a level of accuracy on par with the best ML potentials for single molecules or materials, while remaining applicable to the general class of organic molecules composed of the elements CHNO.

  7. passive and active measurements for some ceramic samples

    International Nuclear Information System (INIS)

    Hassan, M.F.; Said, S.A.; Ali, M.A.; Szegedi, S.

    2004-01-01

    passive measurements for an imported natural ore (zirconium silicate) used in ceramic industries were carried out to identify its radioactivity . this work was done for ceramic quality control purposes. accurate gamma spectrometers with 30% and 70% detector efficiencies were used in the measurements. the 235 U, 238 U and 232 Th radioactivity were determined . for the sake of comparison already manufactured different ceramic samples were investigated applying fast neutrons activation analysis (FNAA) and X-Ray florescence (XRF) techniques. the obtained results were discussed with the tabulated international radioactivity levels for building materials

  8. Specific activity of 129I in environmental samples

    International Nuclear Information System (INIS)

    Ravi, P.M.; Iyer, M.R.; Bhat, I.S.; Somasundaram, S.; Subramanian, M.S.

    1988-01-01

    129 I finds its way into the environment as a result of man-made nuclear operations. It is also formed by the interaction of cosmic rays with xenon isotopes and spontaneous fission of naturally occurring uranium. 129 I and stable 127 I contents of thyroid, milk, seaweed and aplysia cell samples collected from around a fuel reprocessing plant were estimated by neutron activation analysis method. The annual 129 I intake of an individual works out to be about 0.3 Bq as compared to the natural radioactivity content in human body of about 5000 Bq. (author). 3 tabs

  9. Neutron-activation analysis of routine mineral-processing samples

    International Nuclear Information System (INIS)

    Watterson, J.; Eddy, B.; Pearton, D.

    1974-01-01

    Instrumental neutron-activation analysis was applied to a suite of typical mineral-processing samples to establish which elements can be rapidly determined in them by this technique. A total of 35 elements can be determined with precisions (from the counting statistics) ranging from better than 1 per cent to approximately 20 per cent. The elements that can be determined have been tabulated together with the experimental conditions, the precision from the counting statistics, and the estimated number of analyses possible per day. With an automated system, this number can be as high as 150 in the most favourable cases [af

  10. β-Galactosidase activity of commercial lactase samples in raw and pasteurized milk at refrigerated temperatures.

    Science.gov (United States)

    Horner, T W; Dunn, M L; Eggett, D L; Ogden, L V

    2011-07-01

    Many consumers are unable to enjoy the benefits of milk due to lactose intolerance. Lactose-free milk is available but at about 2 times the cost of regular milk or greater, it may be difficult for consumers to afford. The high cost of lactose-free milk is due in part to the added cost of the lactose hydrolysis process. Hydrolysis at refrigerated temperatures, possibly in the bulk tank or package, could increase the flexibility of the process and potentially reduce the cost. A rapid β-galactosidase assay was used to determine the relative activity of commercially available lactase samples at different temperatures. Four enzymes exhibited low-temperature activity and were added to refrigerated raw and pasteurized milk at various concentrations and allowed to react for various lengths of time. The degree of lactose hydrolysis by each of the enzymes as a function of time and enzyme concentration was determined by HPLC. The 2 most active enzymes, as determined by the β-galactosidase assay, hydrolyzed over 98% of the lactose in 24h at 2°C using the supplier's recommended dosage. The other 2 enzymes hydrolyzed over 95% of the lactose in 24h at twice the supplier's recommended dosage at 2°C. Results were consistent in all milk types tested. The results show that it is feasible to hydrolyze lactose during refrigerated storage of milk using currently available enzymes. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Nondestructive neutron activation analysis of volcanic samples: Hawaii

    International Nuclear Information System (INIS)

    Zoller, W.H.; Finnegan, D.L.; Crowe, B.

    1986-01-01

    Samples of volcanic emissions have been collected between and during eruptions of both Kilauea and Mauna Loa volcanoes during the last three years. Airborne particles have been collected on Teflon filters and acidic gases on base-impregnated cellulose filters. Chemically neutral gas-phase species are collected on charcoal-coated cellulose filters. The primary analytical technique used is nondestructive neutron activation analysis, which has been used to determine the quantities of up to 35 elements on the different filters. The use of neutron activation analysis makes it possible to analyze for a wide range of elements in the different matrices used for the collection and to learn about the distribution between particles and gas phases for each of the elements

  12. Elemental analysis of brazing alloy samples by neutron activation technique

    International Nuclear Information System (INIS)

    Eissa, E.A.; Rofail, N.B.; Hassan, A.M.; El-Shershaby, A.; Walley El-Dine, N.

    1996-01-01

    Two brazing alloy samples (C P 2 and C P 3 ) have been investigated by Neutron activation analysis (NAA) technique in order to identify and estimate their constituent elements. The pneumatic irradiation rabbit system (PIRS), installed at the first egyptian research reactor (ETRR-1) was used for short-time irradiation (30 s) with a thermal neutron flux of 1.6 x 10 1 1 n/cm 2 /s in the reactor reflector, where the thermal to epithermal neutron flux ratio is 106. Long-time irradiation (48 hours) was performed at reactor core periphery with thermal neutron flux of 3.34 x 10 1 2 n/cm 2 /s, and thermal to epithermal neutron flux ratio of 79. Activation by epithermal neutrons was taken into account for the (1/v) and resonance neutron absorption in both methods. A hyper pure germanium detection system was used for gamma-ray acquisitions. The concentration values of Al, Cr, Fe, Co, Cu, Zn, Se, Ag and Sb were estimated as percentages of the sample weight and compared with reported values. 1 tab

  13. Elemental analysis of brazing alloy samples by neutron activation technique

    Energy Technology Data Exchange (ETDEWEB)

    Eissa, E A; Rofail, N B; Hassan, A M [Reactor and Neutron physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); El-Shershaby, A; Walley El-Dine, N [Physics Department, Faculty of Girls, Ain Shams Universty, Cairo (Egypt)

    1997-12-31

    Two brazing alloy samples (C P{sup 2} and C P{sup 3}) have been investigated by Neutron activation analysis (NAA) technique in order to identify and estimate their constituent elements. The pneumatic irradiation rabbit system (PIRS), installed at the first egyptian research reactor (ETRR-1) was used for short-time irradiation (30 s) with a thermal neutron flux of 1.6 x 10{sup 1}1 n/cm{sup 2}/s in the reactor reflector, where the thermal to epithermal neutron flux ratio is 106. Long-time irradiation (48 hours) was performed at reactor core periphery with thermal neutron flux of 3.34 x 10{sup 1}2 n/cm{sup 2}/s, and thermal to epithermal neutron flux ratio of 79. Activation by epithermal neutrons was taken into account for the (1/v) and resonance neutron absorption in both methods. A hyper pure germanium detection system was used for gamma-ray acquisitions. The concentration values of Al, Cr, Fe, Co, Cu, Zn, Se, Ag and Sb were estimated as percentages of the sample weight and compared with reported values. 1 tab.

  14. Measurements of {sup 55}Fe activity in activated steel samples with GEMPix

    Energy Technology Data Exchange (ETDEWEB)

    Curioni, A. [CERN, 1211 Geneva 23 (Switzerland); Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Dinar, N. [CERN, 1211 Geneva 23 (Switzerland); Université de Paris VII, 5 rue Thomas-Mann, 75013 Paris (France); La Torre, F.P. [CERN, 1211 Geneva 23 (Switzerland); Leidner, J., E-mail: johannes.leidner@cern.ch [CERN, 1211 Geneva 23 (Switzerland); RWTH Aachen, Templergraben 55, 52056 Aachen (Germany); Murtas, F. [CERN, 1211 Geneva 23 (Switzerland); INFN-LNF, Via E. Fermi 40, 00044 Frascati (Italy); Puddu, S.; Silari, M. [CERN, 1211 Geneva 23 (Switzerland)

    2017-03-21

    In this paper we present a novel method, based on the recently developed GEMPix detector, to measure the {sup 55}Fe content in samples of metallic material activated during operation of CERN accelerators and experimental facilities. The GEMPix, a gas detector with highly pixelated read-out, has been obtained by coupling a triple Gas Electron Multiplier (GEM) to a quad Timepix ASIC. Sample preparation, measurements performed on 45 samples and data analysis are described. The calibration factor (counts per second per unit specific activity) has been obtained via measurements of the {sup 55}Fe activity determined by radiochemical analysis of the same samples. Detection limit and sensitivity to the current Swiss exemption limit are calculated. Comparison with radiochemical analysis shows inconsistency for the sensitivity for only two samples, most likely due to underestimated uncertainties of the GEMPix analysis. An operative test phase of this technique is already planned at CERN.

  15. Active sampling technique to enhance chemical signature of buried explosives

    Science.gov (United States)

    Lovell, John S.; French, Patrick D.

    2004-09-01

    Deminers and dismounted countermine engineers commonly use metal detectors, ground penetrating radar and probes to locate mines. Many modern landmines have a very low metal content, which severely limits the effectiveness of metal detectors. Canines have also been used for landmine detection for decades. Experiments have shown that canines smell the explosives which are known to leak from most types of landmines. The fact that dogs can detect landmines indicates that vapor sensing is a viable approach to landmine detection. Several groups are currently developing systems to detect landmines by "sniffing" for the ultra-trace explosive vapors above the soil. The amount of material that is available to passive vapor sensing systems is limited to no more than the vapor in equilibrium with the explosive related chemicals (ERCs) distributed in the surface soils over and near the landmine. The low equilibrium vapor pressure of TNT in the soil/atmosphere boundary layer and the limited volume of the boundary layer air imply that passive chemical vapor sensing systems require sensitivities in the picogram range, or lower. ADA is working to overcome many of the limitations of passive sampling methods, by the use of an active sampling method that employs a high-powered (1,200+ joules) strobe lamp to create a highly amplified plume of vapor and/or ERC-bearing fine particulates. Initial investigations have demonstrated that this approach can amplify the detectability of TNT by two or three orders of magnitude. This new active sampling technique could be used with any suitable explosive sensor.

  16. Field data analysis of active chlorine-containing stormwater samples.

    Science.gov (United States)

    Zhang, Qianyi; Gaafar, Mohamed; Yang, Rong-Cai; Ding, Chen; Davies, Evan G R; Bolton, James R; Liu, Yang

    2018-01-15

    Many municipalities in Canada and all over the world use chloramination for drinking water secondary disinfection to avoid DBPs formation from conventional chlorination. However, the long-lasting monochloramine (NH 2 Cl) disinfectant can pose a significant risk to aquatic life through its introduction into municipal storm sewer systems and thus fresh water sources by residential, commercial, and industrial water uses. To establish general total active chlorine (TAC) concentrations in discharges from storm sewers, the TAC concentration was measured in stormwater samples in Edmonton, Alberta, Canada, during the summers of 2015 and 2016 under both dry and wet weather conditions. The field-sampling results showed TAC concentration variations from 0.02 to 0.77 mg/L in summer 2015, which exceeds the discharge effluent limit of 0.02 mg/L. As compared to 2015, the TAC concentrations were significantly lower during the summer 2016 (0-0.24 mg/L), for which it is believed that the higher precipitation during summer 2016 reduced outdoor tap water uses. Since many other cities also use chloramines as disinfectants for drinking water disinfection, the TAC analysis from Edmonton may prove useful for other regions as well. Other physicochemical and biological characteristics of stormwater and storm sewer biofilm samples were also analyzed, and no significant difference was found during these two years. Higher density of AOB and NOB detected in the storm sewer biofilm of residential areas - as compared with other areas - generally correlated to high concentrations of ammonium and nitrite in this region in both of the two years, and they may have contributed to the TAC decay in the storm sewers. The NH 2 Cl decay laboratory experiments illustrate that dissolved organic carbon (DOC) concentration is the dominant factor in determining the NH 2 Cl decay rate in stormwater samples. The high DOC concentrations detected from a downstream industrial sampling location may contribute to a

  17. Multielement neutron activation analysis of underground water samples

    International Nuclear Information System (INIS)

    Kusaka, Yuzuru; Tsuji, Haruo; Fujimoto, Yuzo; Ishida, Keiko; Mamuro, Tetsuo.

    1980-01-01

    An instrumental neutron activation analysis by gamma-ray spectrometry with high resolution and large volume Ge (Li) detectors followed by data processing with an electronic computer was applied to the multielemental analysis to elucidate the chemical qualities of the underground water which has been widely used in the sake brewing industries in Mikage, Uozaki and Nishinomiya districts, called as miyamizu. The evaporated residues of the water samples were subjected to the neutron irradiations in reactor for 1 min at a thermal flux of 1.5 x 10 12 n.cm -2 .sec -1 and for 30 hrs at a thermal flux of 9.3 x 10 11 n.cm -2 .sec -1 or for 5 hrs at a thermal flux of 3.9 x 10 12 n.cm -2 .sec -1 . Thus, 11 elements in the former short irradiation and 38 elements in the latter two kinds of long irradiation can be analyzed. Conventional chemical analysis including atomic absorption method and others are also applied on the same samples, and putting the all results together, some considerations concerning the geochemical meaning of the analytical values are made. (author)

  18. Multi-element neutron activation analysis of Brazilian coal samples

    International Nuclear Information System (INIS)

    Atalla, L.T.; Requejo, C.S.

    1982-09-01

    The elements U, Th, La, Ce, Nd, Sm, Eu, Dy, Tb, Yb, Lu, Sc, Ta, Hf, Co, Ni, Cr, Mo, Ti, V, W, In, Ga, Mn, Ba, Sr, Mg, Rb, Cs, K, Cl, Br, As, Sb, Au, Ca, Al and Fe were determined in coal samples by instrumental neutron activation analysis, by using both thermal and epithermal neutron irradiations. The irradiation times were 10 minutes and 8 or 16 hours in a position where the thermal neutron flux was about 10 12 n.cm - 2 .s - 1 and 72 non-consecutive hours for epithermal irradiation at a flux of about 10 11 n.Cm - 2 .s - 1 . After the instrumental analysis of the above mentioned elements, Zn and Se were determined with chemical separation. The relative standard deviation of, at least, 4 determinations was about + - 10% for the majority of the results. The coal samples analysed were supplied by: Cia. Estadual da Tecnologia e Saneamento Basico (CETESB-SP), Cia. de Pesquisas e Lavras Minerais (COPELMI-RS), Cia. Carbonifera Urussunga (SC), Cia. Carbonifera Prospera (SC), Cia. Carbonifera Treviso (SC), Cia. Nacional de Mineracao de Carvao do Barro Branco (SC) and Comissao Nacional de Energia Nuclear (CNEN-RJ). (Author) [pt

  19. Densidade global de solos medida com anel volumétrico e por cachimbagem de terra fina seca ao ar Bulk density of soil samples measured in the field and through volume measurement of sieved soil

    Directory of Open Access Journals (Sweden)

    Bernardo Van Raij

    1989-01-01

    Full Text Available Em laboratórios de rotina de fertilidade do solo, a medida de quantidade de terra para análise é feita em volume, mediante utensílios chamados "cachimbos", que permitem medir volumes de terra. Admite-se que essas medidas reflitam a quantidade de terra existente em volume de solo similar em condições de campo. Essa hipótese foi avaliada neste trabalho, por doze amostras dos horizontes A e B de seis perfis de solos. A densidade em condições de campo foi avaliada por anel volumétrico e, no laboratório, por meio de cachimbos de diversos tamanhos. A cachimbagem revelou-se bastante precisa. Os valores de densidade global calculada variaram de 0,63 a 1,46g/cm³ para medidas de campo e de 0,91 a 1,33g/cm³ para medidas com cachimbos. Portanto, a medida de laboratório subestimou valores altos de densidade e deu resultados mais elevados para valores de campo mais baixos.In soil testing laboratories, soil samples for chemical analysis are usually measured by volume, using appropriate measuring spoons. It is tacitly assumed that such measurements would reflect amounts of soil existing in the same volume under field conditions. This hypothesis was tested, using 12 soil samples of the A and B horizons of six soil profiles. Bulk density in the field was evaluated through a cylindrical metal sampler of 50cm³ and in the laboratory using spoons of different sizes. Measurements of soil volumes by spoons were quite precise. Values of bulk density varied between 0.63 and 1.46g/cm³ for field measurements and between 0.91 and 1.33g/cm³ for laboratory measurements with spoons. Thus, laboratory measurements overestimated lower values of bulk densities and underestimated the higher ones.

  20. Effect of CuF2 on the Synthesis and Superconducting Properties of (Bi,Pb)2Sr2Ca2Cu3O10 Bulk Ceramic Samples

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Andersen, Niels Hessel

    2013-01-01

    precursors. In both cases, CuF2 resulted in a clear lowering of the reaction temperature. The superconducting and secondary phase grains are larger in the CuF2 doped samples but the critical transition temperature and the lattice parameters of the high T c phase are not affected. EDS analysis shows...

  1. Activating antioxidant enzymes, hyoscyamine and scopolamine biosynthesis of Hyoscyamus niger L. plants with nano-sized titanium dioxide and bulk application

    Directory of Open Access Journals (Sweden)

    Mansour GHORBANPOUR

    2015-11-01

    Full Text Available  Application of nanotechnology is now widely distributed overall the life, especially in agricultural systems. This study intended to indicate the impacts of nano-sized titanium dioxide particles (NT and bulk (BT on antioxidant enzymes activities including superoxide dismutase (SOD, peroxidase (POX and catalase (CAT, and variations of two major tropane alkaloids such as hyoscyamine (HYO and scopolamine (SCO in Hyoscyamus niger L. Plants were treated with different concentrations of NT and BT (0, 20, 40 and 80 mg l-1. Alkaloids extracted were identified by gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS analysis. Results showed that SOD activity increased with increasing titanium dioxide concentration in both nano-particles and bulk treated plants. However, the highest and the lowest POX activity were observed in plants exposed to NT at 40 mg l-1 and control, respectively. Generally, all tested enzymes activities were higher in NT treated plants that those of BT except CAT activity at 80 mg l-1. The highest alkaloids content values, HYO: 0.286 g kg-1 and SCO: 0.126 g kg-1, were achieved in plants treated with NT at 80 and 20 mg l-1, respectively. The maximum and minimum plant biomass and subsequently total alkaloids yield were obtained in plants exposed to NT at 40 mg l-1 and controls, respectively. Our results suggest that NT in appropriate level (40 mg l-1 may act as an elicitor for biochemical responses and tropane alkaloids biosynthesis in H. niger plants. 

  2. Bulk oil clauses

    International Nuclear Information System (INIS)

    Gough, N.

    1993-01-01

    The Institute Bulk Oil Clauses produced by the London market and the American SP-13c Clauses are examined in detail in this article. The duration and perils covered are discussed, and exclusions, adjustment clause 15 of the Institute Bulk Oil Clauses, Institute War Clauses (Cargo), and Institute Strikes Clauses (Bulk Oil) are outlined. (UK)

  3. Sampling

    CERN Document Server

    Thompson, Steven K

    2012-01-01

    Praise for the Second Edition "This book has never had a competitor. It is the only book that takes a broad approach to sampling . . . any good personal statistics library should include a copy of this book." —Technometrics "Well-written . . . an excellent book on an important subject. Highly recommended." —Choice "An ideal reference for scientific researchers and other professionals who use sampling." —Zentralblatt Math Features new developments in the field combined with all aspects of obtaining, interpreting, and using sample data Sampling provides an up-to-date treat

  4. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    Science.gov (United States)

    Maeng, Sung Kyu; Sharma, Saroj K.; Abel, Chol D. T.; Magic-Knezev, Aleksandra; Song, Kyung-Guen; Amy, Gary L.

    2012-10-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR) treatment processes. The fate of bulk OM and PhACs during an MAR is important to assess post-treatment requirements. Biodegradable OM from EfOM, originating from biological wastewater treatment, was effectively removed during soil passage. Based on a fluorescence excitation-emission matrix (F-EEM) analysis of wastewater effluent-dominated (WWE-dom) surface water (SW), protein-like substances, i.e., biopolymers, were removed more favorably than fluorescent humic-like substances under oxic compared to anoxic conditions. However, there was no preferential removal of biopolymers or humic substances, determined as dissolved organic carbon (DOC) observed via liquid chromatography with online organic carbon detection (LC-OCD) analysis. Most of the selected PhACs exhibited removal efficiencies of greater than 90% in both SW and WWE-dom SW. However, the removal efficiencies of bezafibrate, diclofenac and gemfibrozil were relatively low in WWE-dom SW, which contained more biodegradable OM than did SW (copiotrophic metabolism). Based on this study, low biodegradable fractions such as humic substances in MR may have enhanced the degradation of diclofenac, gemfibrozil and bezafibrate by inducing an oligotrophic microbial community via long term starvation. Both carbamazepine and clofibric acid showed persistent behaviors and were not influenced by EfOM.

  5. Fate of bulk organic matter, nitrogen, and pharmaceutically active compounds in batch experiments simulating soil aquifer treatment (SAT) using primary effluent

    KAUST Repository

    Abel, Chol D T

    2013-06-30

    Reduction of bulk organic matter, nitrogen, and pharmaceutically active compounds from primary effluent during managed aquifer recharge was investigated using laboratory-scale batch reactors. Biologically stable batch reactors were spiked with different concentrations of sodium azide to inhibit biological activity and probe the effect of microbial activity on attenuation of various pollutants of concern. The experimental results obtained revealed that removal of dissolved organic carbon correlated with active microbial biomass. Furthermore, addition of 2 mM of sodium azide affected nitrite-oxidizing bacteria leading to accumulation of nitrite-nitrogen in the reactors while an ammonium-nitrogen reduction of 95.5 % was achieved. Removal efficiencies of the hydrophilic neutral compounds phenacetin, paracetamol, and caffeine were independent of the extent of the active microbial biomass and were >90 % in all reactors, whereas removal of pentoxifylline was dependent on the biological stability of the reactor. However, hydrophobic ionic compounds exhibited removal efficiency >80 % in batch reactors with the highest biological activity as evidenced by high concentration of adenosine triphosphate. © 2013 Springer Science+Business Media Dordrecht.

  6. Fate of bulk organic matter, nitrogen, and pharmaceutically active compounds in batch experiments simulating soil aquifer treatment (SAT) using primary effluent

    KAUST Repository

    Abel, Chol D T; Sharma, Saroj K.; Maeng, Sungkyu; Magic-Knezev, Aleksandra; Kennedy, Maria Dolores; Amy, Gary L.

    2013-01-01

    Reduction of bulk organic matter, nitrogen, and pharmaceutically active compounds from primary effluent during managed aquifer recharge was investigated using laboratory-scale batch reactors. Biologically stable batch reactors were spiked with different concentrations of sodium azide to inhibit biological activity and probe the effect of microbial activity on attenuation of various pollutants of concern. The experimental results obtained revealed that removal of dissolved organic carbon correlated with active microbial biomass. Furthermore, addition of 2 mM of sodium azide affected nitrite-oxidizing bacteria leading to accumulation of nitrite-nitrogen in the reactors while an ammonium-nitrogen reduction of 95.5 % was achieved. Removal efficiencies of the hydrophilic neutral compounds phenacetin, paracetamol, and caffeine were independent of the extent of the active microbial biomass and were >90 % in all reactors, whereas removal of pentoxifylline was dependent on the biological stability of the reactor. However, hydrophobic ionic compounds exhibited removal efficiency >80 % in batch reactors with the highest biological activity as evidenced by high concentration of adenosine triphosphate. © 2013 Springer Science+Business Media Dordrecht.

  7. Use of Lecane rotifers for limiting Thiothrix filamentous bacteria in bulking activated sludge in a dairy wastewater treatment plant

    Directory of Open Access Journals (Sweden)

    Kowalska Ewa

    2014-01-01

    Full Text Available Excessive growth of filamentous bacteria is a serious problem in many dairy wastewater treatment plants (WWTPs. The objective of the study was to determine whether Lecane inermis rotifers were able to reduce the density of Thiothrix bacteria in activated sludge originating from a dairy WWTP, as well as to identify the impact of rotifers on other organisms in sludge. On a laboratory scale, three experiments were conducted in which activated sludge with a predominance of Thiothrix was inoculated with rotifers at an initial concentration of app. 600 individuals/mL. The results showed that the rotifers, by feeding on the bacterium filaments, are able to reduce significantly the quantity of Thiothrix. A decline in Thiothrix abundance coincided with an improvement of the sedimentation properties of activated sludge. In addition, it was proven that Lecane inermis did not negatively affect the number of Protozoa and Metazoa in activated sludge.

  8. Sampling quality assurance guidance in support of EM environmental sampling and analysis activities

    International Nuclear Information System (INIS)

    1994-05-01

    This document introduces quality assurance guidance pertaining to the design and implementation of sampling procedures and processes for collecting environmental data for DOE's Office of EM (Environmental Restoration and Waste Management)

  9. Guidance for establishment and implementation of field sample management programs in support of EM environmental sampling and analysis activities

    International Nuclear Information System (INIS)

    1994-01-01

    The role of the National Sample Management Program (NSMP) proposed by the Department of Energy's Office of Environmental Management (EM) is to be a resource for EM programs and for local Field Sample Management Programs (FSMPs). It will be a source of information on sample analysis and data collection within the DOE complex. The purpose of this document is to establish the suggested scope of the FSMP activities to be performed under each Operations Office, list the drivers under which the program will operate, define terms and list references. This guidance will apply only to EM sampling and analysis activities associated with project planning, contracting, laboratory selection, sample collection, sample transportation, laboratory analysis and data management

  10. [Effects of controlled release blend bulk urea on soil nitrogen and soil enzyme activity in wheat and rice fields].

    Science.gov (United States)

    Zhang, Jing Sheng; Wang, Chang Quan; Li, Bing; Liang, Jing Yue; He, Jie; Xiang, Hao; Yin, Bin; Luo, Jing

    2017-06-18

    A field experiment was conducted to investigate the effect of controlled-release fertilizer (CRF) combined with urea (UR) on the soil fertility and environment in wheat-rice rotation system. Changes in four forms of nitrogen (total nitrogen, ammonium nitrogen, nitrate nitrogen, and microbial biomass nitrogen) and in activities of three soil enzymes participating in nitrogen transformation (urease, protease, and nitrate reductase) were measured in seven fertilization treatments (no fertilization, routine fertilization, 10%CRF+90%UR, 20%CRF+80%UR, 40%CRF+60%UR, 80%CRF+20%UR, and 100%CRF). The results showed that soil total nitrogen was stable in the whole growth period of wheat and rice. There was no significant difference among the treatments of over 20% CRF in soil total nitrogen content of wheat and rice. The soil inorganic nitrogen content was increased dramatically in treatments of 40% or above CRF during the mid-late growing stages of wheat and rice. With the advance of the growth period, conventional fertilization significantly decreased soil microbial biomass nitrogen, but the treatments of 40% and above CRF increased the soil microbial biomass nitrogen significantly. The soil enzyme activities were increased with over 40% of CRF in the mid-late growing stage of wheat and rice. By increasing the CRF ratio, the soil protease activity and nitrate reductase activity were improved gradually, and peaked in 100% CRF. The treatments of above 20% CRF could decrease the urease activity in tillering stage of rice and delay the peak of ammonium nitrogen, which would benefit nitrogen loss reduction. The treatments of 40% and above CRF were beneficial to improving soil nitrogen supply and enhancing soil urease and protease activities, which could promote the effectiveness of nitrogen during the later growth stages of wheat and rice. The 100% CRF treatment improved the nitrate reductase activity significantly during the later stage of wheat and rice. Compared with the

  11. Development of disposable bulk-modified screen-printed electrode based on bismuth oxide for stripping chronopotentiometric analysis of lead (II) and cadmium (II) in soil and water samples

    International Nuclear Information System (INIS)

    Kadara, Rashid O.; Tothill, Ibtisam E.

    2008-01-01

    A bulk-modified screen-printed carbon electrode characterised for metal ion detection is presented. Bismuth oxide (Bi 2 O 3 ) was mixed with graphite-carbon ink to obtain the modified electrode. The best composition was 2% Bi 2 O 3 (wt%) in the graphite-carbon ink. The modified electrode with onboard screen-printed carbon counter and silver-silver chloride pseudo-reference electrodes exhibited good performance in the electrochemical measurement of lead (II) and cadmium (II). The electrode displayed excellent linear behaviour in the concentration range examined (20-300 μg L -1 ) with limits of detection of 8 and 16 μg L -1 for both lead (II) and cadmium (II), respectively. The analytical utility of the modified electrode was illustrated by the stripping chronopotentiometric determinations of lead (II) in soil extracts and wastewater samples

  12. Development of disposable bulk-modified screen-printed electrode based on bismuth oxide for stripping chronopotentiometric analysis of lead (II) and cadmium (II) in soil and water samples

    Energy Technology Data Exchange (ETDEWEB)

    Kadara, Rashid O. [Cranfield Health, Cranfield University, Silsoe, Bedfordshire MK45 4DT (United Kingdom); School of Science and Technology, Nottingham Trent University, Clifton Campus, Nottinghamshire NG11 8NS (United Kingdom)], E-mail: kayusee2001@yahoo.co.uk; Tothill, Ibtisam E. [Cranfield Health, Cranfield University, Silsoe, Bedfordshire MK45 4DT (United Kingdom)

    2008-08-08

    A bulk-modified screen-printed carbon electrode characterised for metal ion detection is presented. Bismuth oxide (Bi{sub 2}O{sub 3}) was mixed with graphite-carbon ink to obtain the modified electrode. The best composition was 2% Bi{sub 2}O{sub 3} (wt%) in the graphite-carbon ink. The modified electrode with onboard screen-printed carbon counter and silver-silver chloride pseudo-reference electrodes exhibited good performance in the electrochemical measurement of lead (II) and cadmium (II). The electrode displayed excellent linear behaviour in the concentration range examined (20-300 {mu}g L{sup -1}) with limits of detection of 8 and 16 {mu}g L{sup -1} for both lead (II) and cadmium (II), respectively. The analytical utility of the modified electrode was illustrated by the stripping chronopotentiometric determinations of lead (II) in soil extracts and wastewater samples.

  13. Shear transformation zone activation during deformation in bulk metallic glasses characterized using a new indentation creep technique

    Science.gov (United States)

    J.B. Puthoff; H.B. Cao; Joseph E. Jakes; P.M. Voyles; D.S. Stone

    2009-01-01

    We have developed a novel type of nanoindentation creep experiment, called broadband nanoindentation creep (BNC), and used it to characterize the thermal activation of shear transformation zones (STZs) in three BMGs in the Zr-Cu-Al system. Using BNC, material hardness can be determined across a wide range of strain rates (10–4 to 10 s–...

  14. Inexpensive, rapid procedure for bulk purification of cellulase-free. beta. -1,4-D-xylanase of high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Tan, L.U.L.; Yu, E.K.C.; Louis-Seize, G.W.; Saddler, J.N.

    1987-01-01

    A process has been developed for the bulk purification of cellulase-free ..beta..-14-D-xylanase from the fungus Tirchoderma harzianum E58. The process involved the primary step of ultrafiltering the culture filtrate via a 10,000-molecular-weight cut-off membrane to separate the cellulase (retentate) and xylanase (permeate) fractions. The cellulase component was concentrated by 40- to 60-fold, resulting in an enzyme complex that could effectively hydrolyze high concentrations of cellulose and xylan to glucose and xylose. The xylanase was concentrated and solvent exchanged by adsorption to a cationic exchanger, SP-ZetaPrep 250, followed by elution with a pH change in the buffer to give a purified and concentrated xylanase complex dissolved in a low-salt buffer. The resultant xylanase system was pure by the criteria of sodium dodecyl sulfate polyacrylamide electrophoresis, had a very high specific activity of 2400 IU/mg protein, was virtually free of filter paper activity, and had a ratio of contaminating filter paper activity of 2 x 10/sup -6/. Approximately 3.3 g protein, which contained in excess of 7 x 10/sup 6/ IU xylanase activity was obtained from 17 L original culture filtrate. The process scheme was designed to facilitate scale-up to an industrial level of production.

  15. Activation product analysis in a mixed sample containing both fission and neutron activation products

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Samuel S.; Clark, Sue B.; Eggemeyer, Tere A.; Finn, Erin C.; Hines, C. Corey; King, Mathew D.; Metz, Lori A.; Morley, Shannon M.; Snow, Mathew S.; Wall, Donald E.; Seiner, Brienne N.

    2017-11-02

    Activation analysis of gold (Au) is used to estimate neutron fluence resulting from a criticality event; however, such analyses are complicated by simultaneous production of other gamma-emitting fission products. Confidence in neutron fluence estimates can be increased by quantifying additional activation products such as platinum (Pt), tantalum (Ta), and tungsten (W). This work describes a radiochemical separation procedure for the determination of these activation products. Anion exchange chromatography is used to separate anionic forms of these metals in a nitric acid matrix; thiourea is used to isolate the Au and Pt fraction, followed by removal of the Ta fraction using hydrogen peroxide. W, which is not retained on the first anion exchange column, is transposed to an HCl/HF matrix to enhance retention on a second anion exchange column and finally eluted using HNO3/HF. Chemical separations result in a reduction in the minimum detectable activity by a factor of 287, 207, 141, and 471 for 182Ta, 187W, 197Pt, and 198Au respectively, with greater than 90% recovery for all elements. These results represent the highest recoveries and lowest minimum detectable activities for 182Ta, 187W, 197Pt, and 198Au from mixed fission-activation product samples to date, enabling considerable refinement in the measurement uncertainties for neutron fluences in highly complex sample matrices.

  16. The method of Sample Management in Neutron Activation Analysis Laboratory-Serpong

    International Nuclear Information System (INIS)

    Elisabeth-Ratnawati

    2005-01-01

    In the testing laboratory used by neutron activation analysis method, sample preparation is the main factor and it can't be neglect. The error in the sample preparation can give result with lower accuracy. In this article is explained the scheme of sample preparation i.e sample receive administration, the separate of sample, fluid and solid sample preparation, sample grouping, irradiation, sample counting and holding the sample post irradiation. If the management of samples were good application based on Standard Operation Procedure, therefore each samples has good traceability. To optimize the management of samples is needed the trained and skilled personal and good facility. (author)

  17. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods.

    Science.gov (United States)

    Coes, Alissa L; Paretti, Nicholas V; Foreman, William T; Iverson, Jana L; Alvarez, David A

    2014-03-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19-23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method. Published by Elsevier B.V.

  18. Sampling trace organic compounds in water: a comparison of a continuous active sampler to continuous passive and discrete sampling methods

    Science.gov (United States)

    Coes, Alissa L.; Paretti, Nicholas V.; Foreman, William T.; Iverson, Jana L.; Alvarez, David A.

    2014-01-01

    A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring (CLAM) sampler (C.I.Agent® Storm-Water Solutions) is a submersible, low flow-rate sampler, that continuously draws water through solid-phase extraction media. CLAM samplers were deployed at two wastewater-dominated stream field sites in conjunction with the deployment of polar organic chemical integrative samplers (POCIS) and the collection of discrete (grab) water samples. All samples were analyzed for a suite of 69 TOCs. The CLAM and POCIS samples represent time-integrated samples that accumulate the TOCs present in the water over the deployment period (19–23 h for CLAM and 29 days for POCIS); the discrete samples represent only the TOCs present in the water at the time and place of sampling. Non-metric multi-dimensional scaling and cluster analysis were used to examine patterns in both TOC detections and relative concentrations between the three sampling methods. A greater number of TOCs were detected in the CLAM samples than in corresponding discrete and POCIS samples, but TOC concentrations in the CLAM samples were significantly lower than in the discrete and (or) POCIS samples. Thirteen TOCs of varying polarity were detected by all of the three methods. TOC detections and concentrations obtained by the three sampling methods, however, are dependent on multiple factors. This study found that stream discharge, constituent loading, and compound type all affected TOC concentrations detected by each method. In addition, TOC detections and concentrations were affected by the reporting limits, bias, recovery, and performance of each method.

  19. Comparing near-infrared conventional diffuse reflectance spectroscopy and hyperspectral imaging for determination of the bulk properties of solid samples by multivariate regression: determination of Mooney viscosity and plasticity indices of natural rubber.

    Science.gov (United States)

    Juliano da Silva, Carlos; Pasquini, Celio

    2015-01-21

    Conventional reflectance spectroscopy (NIRS) and hyperspectral imaging (HI) in the near-infrared region (1000-2500 nm) are evaluated and compared, using, as the case study, the determination of relevant properties related to the quality of natural rubber. Mooney viscosity (MV) and plasticity indices (PI) (PI0 - original plasticity, PI30 - plasticity after accelerated aging, and PRI - the plasticity retention index after accelerated aging) of rubber were determined using multivariate regression models. Two hundred and eighty six samples of rubber were measured using conventional and hyperspectral near-infrared imaging reflectance instruments in the range of 1000-2500 nm. The sample set was split into regression (n = 191) and external validation (n = 95) sub-sets. Three instruments were employed for data acquisition: a line scanning hyperspectral camera and two conventional FT-NIR spectrometers. Sample heterogeneity was evaluated using hyperspectral images obtained with a resolution of 150 × 150 μm and principal component analysis. The probed sample area (5 cm(2); 24,000 pixels) to achieve representativeness was found to be equivalent to the average of 6 spectra for a 1 cm diameter probing circular window of one FT-NIR instrument. The other spectrophotometer can probe the whole sample in only one measurement. The results show that the rubber properties can be determined with very similar accuracy and precision by Partial Least Square (PLS) regression models regardless of whether HI-NIR or conventional FT-NIR produce the spectral datasets. The best Root Mean Square Errors of Prediction (RMSEPs) of external validation for MV, PI0, PI30, and PRI were 4.3, 1.8, 3.4, and 5.3%, respectively. Though the quantitative results provided by the three instruments can be considered equivalent, the hyperspectral imaging instrument presents a number of advantages, being about 6 times faster than conventional bulk spectrometers, producing robust spectral data by ensuring sample

  20. Kinetics of growth of semi-spheric pittings in the vicinity repassivation potential depending on bulk concentration of activator anions

    International Nuclear Information System (INIS)

    Frejman, L.I.

    1985-01-01

    A general case of semi-spheric pittings development in aqueous solutions of electrolyte of NaCl or LiCl type at different values of C 0 , usually studied in the range approximately equal to 10 -5 -10 -3 g-ionxcm -3 (approximately equal to 10 -2 -10 0 g-ionxl -1 ), has been analyzed. On the basis of experimental data on participation of anion-activators and water molecules in the process of metal dissolution in pitting, and using the previously obtained equations, kinetics of open and closed semi-spheric pittings during galvanostatic anode polarization in neutral chloride solutions with different volumetric concentration of Cl - -ions (C 0 ) has been considered. In a general case the process kinetics is described by a complex equation, the boundary, more simple forms of which, correspond to the initial (A) and subsequent (B) stages of open pitting development, or to certain stable conditions of closed pitting development

  1. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    KAUST Repository

    Maeng, Sungkyu

    2012-10-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR) treatment processes. The fate of bulk OM and PhACs during an MAR is important to assess post-treatment requirements. Biodegradable OM from EfOM, originating from biological wastewater treatment, was effectively removed during soil passage. Based on a fluorescence excitation-emission matrix (F-EEM) analysis of wastewater effluent-dominated (WWE-dom) surface water (SW), protein-like substances, i.e., biopolymers, were removed more favorably than fluorescent humic-like substances under oxic compared to anoxic conditions. However, there was no preferential removal of biopolymers or humic substances, determined as dissolved organic carbon (DOC) observed via liquid chromatography with online organic carbon detection (LC-OCD) analysis. Most of the selected PhACs exhibited removal efficiencies of greater than 90% in both SW and WWE-dom SW. However, the removal efficiencies of bezafibrate, diclofenac and gemfibrozil were relatively low in WWE-dom SW, which contained more biodegradable OM than did SW (copiotrophic metabolism). Based on this study, low biodegradable fractions such as humic substances in MR may have enhanced the degradation of diclofenac, gemfibrozil and bezafibrate by inducing an oligotrophic microbial community via long term starvation. Both carbamazepine and clofibric acid showed persistent behaviors and were not influenced by EfOM. © 2012 Elsevier B.V.

  2. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study.

    Science.gov (United States)

    Maeng, Sung Kyu; Sharma, Saroj K; Abel, Chol D T; Magic-Knezev, Aleksandra; Song, Kyung-Guen; Amy, Gary L

    2012-10-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR) treatment processes. The fate of bulk OM and PhACs during an MAR is important to assess post-treatment requirements. Biodegradable OM from EfOM, originating from biological wastewater treatment, was effectively removed during soil passage. Based on a fluorescence excitation-emission matrix (F-EEM) analysis of wastewater effluent-dominated (WWE-dom) surface water (SW), protein-like substances, i.e., biopolymers, were removed more favorably than fluorescent humic-like substances under oxic compared to anoxic conditions. However, there was no preferential removal of biopolymers or humic substances, determined as dissolved organic carbon (DOC) observed via liquid chromatography with online organic carbon detection (LC-OCD) analysis. Most of the selected PhACs exhibited removal efficiencies of greater than 90% in both SW and WWE-dom SW. However, the removal efficiencies of bezafibrate, diclofenac and gemfibrozil were relatively low in WWE-dom SW, which contained more biodegradable OM than did SW (copiotrophic metabolism). Based on this study, low biodegradable fractions such as humic substances in MR may have enhanced the degradation of diclofenac, gemfibrozil and bezafibrate by inducing an oligotrophic microbial community via long term starvation. Both carbamazepine and clofibric acid showed persistent behaviors and were not influenced by EfOM. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    International Nuclear Information System (INIS)

    Buckova, M; Kasparova, M; Dostalova, T; Jelinkova, H; Sulc, J; Nemec, M; Fibrich, M; Bradna, P; Miyagi, M

    2013-01-01

    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel. (paper)

  4. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    Science.gov (United States)

    Buckova, M.; Kasparova, M.; Dostalova, T.; Jelinkova, H.; Sulc, J.; Nemec, M.; Fibrich, M.; Bradna, P.; Miyagi, M.

    2013-05-01

    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel.

  5. Estimation of tritium activity in bioassay samples having chemiluminescence

    International Nuclear Information System (INIS)

    Dwivedi, R.K.; Manu, Kumar; Kumar, Vinay; Soni, Ashish; Kaushik, A.K.; Tiwari, S.K.; Gupta, Ashok

    2008-01-01

    Tritium is recognized as major internal dose contributor in PHWR type of reactors. Estimation of internal dose due to tritium is carried out by analyzing urine samples in liquid scintillation analyzer (LSA). Presence of residual biochemical species in urine samples of some individuals under medical administration shows significant amount of chemiluminescence. If appropriate care is not taken the results obtained by liquid scintillation counter may be mistaken as genuine uptake of tritium. The distillation method described in this paper is used at RAPS-3 and 4 to assess correct tritium uptake. (author)

  6. Jazz Listening Activities: Children's Literature and Authentic Music Samples.

    Science.gov (United States)

    McDonald, Nan L.; Fisher, Douglas; Helzer, Rick

    2002-01-01

    Describes a unit that is appropriate for upper elementary and middle school students that focuses on jazz music using biographies about jazz musicians. Discusses the five sections of the unit. Includes a list of "Suggested Jazz Listening Samples," jazz videos, and a bibliography of resources related to jazz music. (CMK)

  7. 29 CFR 794.137 - Effect of activities other than “wholesale or bulk distribution of petroleum products.”

    Science.gov (United States)

    2010-07-01

    ... distribution of petroleum products.â 794.137 Section 794.137 Labor Regulations Relating to Labor (Continued... RELATED TO REGULATIONS PARTIAL OVERTIME EXEMPTION FOR EMPLOYEES OF WHOLESALE OR BULK PETROLEUM... other than “wholesale or bulk distribution of petroleum products.” As previously noted, in some cases...

  8. Heterosexual sexual behaviour in a sample of homosexually active men.

    OpenAIRE

    Fitzpatrick, R; Hart, G; Boulton, M; McLean, J; Dawson, J

    1989-01-01

    Three hundred and fifty six homosexually active men were recruited in 1988 for a study by interview of sexual behaviour. Thirty two per cent had homosexual passive anal sex in the previous month and 60% in the year before interview. Anal sex and unprotected anal sex were more common with regular than non-regular partners. Heterosexual sex was reported by 4% of men in the last month and 10% for the last year. Sixteen per cent of heterosexually active men reported anal sex with a female partner...

  9. An active radon sampling device for high humidity places

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda Urquijo s/n 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda Urquijo s/n 48013 Bilbao (Spain); Alegria, N.; Herranz, M. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda Urquijo s/n 48013 Bilbao (Spain)

    2010-01-15

    An active radon measurement device has been developed to be used in workplaces with a relative humidity of 100% for spot measurements of radon concentration. A mathematical model based on the convective-diffusive transport equation is used in the design of this system, which has been used to measure the radon concentration in the Pozalagua cave (Biscay, at Northern of Spain). From the obtained radon values the public and workers doses have been obtained.

  10. Large area bulk superconductors

    Science.gov (United States)

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  11. The determination of chromium in water samples by neutron activation analysis after preconcentration on activated carbon

    International Nuclear Information System (INIS)

    Sloot, H.A. van der

    1977-01-01

    A method is presented for the determination of chromium in sea- and fresh water. Chromium is concentrated on activated carbon from a neutral solution after a previous reduction of chromate with sodium sulfite at pH 1.5. The adsorption conditions, acidity, concentrations, amount of carbon, stirring-time, sample-volume, salinity, the influence of storage on the ratio of tervalent to hexavalent chromium, were investigated. The final determination of the total chromium content is performed by instrumental neutron-activation analysis. By preconcentration on activated carbon, a differentiation between tervalent and hexavalent chromium is possible. A separate determination of both species is not yet feasible due to the high carbon blank and to the necessity of measuring the adsorption percentage on carbon. The lower limit of determination, which depends on the value of the carbon blank, is 0.05 μg Cr/l with a precision of 20%. The determination is hampered by the considerable blank from the carbon. The use of activated carbon prepared from recrystallized sugar will probably improve the lower limit of determination and possibly allow the determination of chromate. (T.G.)

  12. Determination of chromium in water samples by neutron activation analysis after preconcentration on activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    van der Sloot, H A [Stichting Reactor Centrum Nederland, Petten

    1977-01-01

    A method is presented for the determination of chromium in sea- and fresh water. Chromium is concentrated on activated carbon from a neutral solution after a previous reduction of chromate with sodium sulfite at pH 1.5. The adsorption conditions, acidity, concentrations, amount of carbon, stirring-time, sample-volume, salinity, the influence of storage on the ratio of tervalent to hexavalent chromium, were investigated. The final determination of the total chromium content is performed by instrumental neutron-activation analysis. By preconcentration on activated carbon, a differentiation between tervalent and hexavalent chromium is possible. A separate determination of both species is not yet feasible due to the high carbon blank and to the necessity of measuring the adsorption percentage on carbon. The lower limit of determination, which depends on the value of the carbon blank, is 0.05 ..mu..g Cr/l with a precision of 20%. The determination is hampered by the considerable blank from the carbon. The use of activated carbon prepared from recrystallized sugar will probably improve the lower limit of determination and possibly allow the determination of chromate.

  13. A new strategy to engineer polymer bulk heterojunction solar cells with thick active layers via self-assembly of the tertiary columnar phase.

    Science.gov (United States)

    Li, Hongfei; Yang, Zhenhua; Pan, Cheng; Jiang, Naisheng; Satija, Sushil K; Xu, Di; Gersappe, Dilip; Nam, Chang-Yong; Rafailovich, Miriam H

    2017-08-17

    We report that the addition of a non-photoactive tertiary polymer phase in the binary bulk heterojunction (BHJ) polymer solar cell leads to a self-assembled columnar nanostructure, enhancing the charge mobilities and photovoltaic efficiency with surprisingly increased optimal active blend thicknesses over 300 nm, 3-4 times larger than that of the binary counterpart. Using the prototypical poly(3-hexylthiophene) (P3HT):fullerene blend as a model BHJ system, we discover that the inert poly(methyl methacrylate) (PMMA) added in the binary BHJ blend self-assembles into vertical columns, which not only template the phase segregation of electron acceptor fullerenes but also induce the out-of-plane rotation of the edge-on-orientated crystalline P3HT phase. Using complementary interrogation methods including neutron reflectivity, X-ray scattering, atomic force microscopy, transmission electron microscopy, and molecular dynamics simulations, we show that the enhanced charge transport originates from the more randomized molecular stacking of the P3HT phase and the spontaneous segregation of fullerenes at the P3HT/PMMA interface, driven by the high surface tension between the two polymeric components. The results demonstrate a potential method for increasing the thicknesses of high-performance polymer BHJ solar cells with improved photovoltaic efficiency, alleviating the burden of stringently controlling the ultrathin blend thickness during the roll-to-roll-type large-area manufacturing environment.

  14. The autoradiographic observation of neutron activated plant samples

    International Nuclear Information System (INIS)

    Koyama, Motoko; Tanizaki, Yoshiyuki

    2003-01-01

    Imaging Plate (IP) is a radiography apparatus of applying photostimulable luminescence. IP has some advantages in comparison with X-ray film, for example, high sensitivity, wide latitude and high fidelity for radiations. The high sensitivity of IP makes it possible to observe the distribution of short-lived nuclides. We obtained autoradiographs of Azuki bean cuttings. In the basal region of Azuki bean cuttings, the intensity of autoradiographs of indole acetic acid (IAA)-treated samples were higher than that of water- and Gibbereline(GA)-treated ones. The high intensity parts of IAA-treated cuttings were extended upwards. The high intensive imaging of basal region treated in IAA indicated that high elemental concentrations were in existence for adventitious root formations. The measurement results by γ-ray spectrometry showed that the Ca content in the Azuki bean cuttings basal region increased in IAA treatment. It seems that the cell division for adventitious root formation needs Ca. In Azuki bean epicotyls, Ca content showed an increase to basal region, though Mg content increased to upper region. (author)

  15. Inventory calculations in sediment samples with heterogeneous plutonium activity distribution

    International Nuclear Information System (INIS)

    Eriksson, M.; Dahlgaard, H.

    2002-01-01

    A method to determine the total inventory of a heterogeneously distributed contamination of marine sediments is described. The study site is the Bylot Sound off the Thule Airbase, NW Greenland, where marine sediments became contaminated with plutonium in 1968 after a nuclear weapons accident. The calculation is based on a gamma spectrometric screening of the 241 Am concentration in 450 one-gram aliquots from 6 sediment cores. A Monte Carlo programme then simulates a probable distribution of the activity, and based on that, a total inventory is estimated by integrating a double exponential function. The present data indicate a total inventory around 3.5 kg, which is 7 times higher than earlier estimates (0.5 kg). The difference is partly explained by the inclusion of hot particles in the present calculation. A large uncertainty is connected to this estimate, and it should be regarded as preliminary. (au)

  16. Bulk Building Material Characterization and Decontamination Using a Concrete Floor and Wall Contamination Profiling Technology

    International Nuclear Information System (INIS)

    Aggarwal, S.; Charters, G.; Blauvelt, D.

    2002-01-01

    The concrete profiling technology, RadPro(trademark) has four major components: a drill with a specialized cutting and sampling head, drill bits, a sample collection unit and a vacuum pump. The equipment in conjunction with portable radiometric instrumentation produces a profile of radiological or chemical contamination through the material being studied. The drill head is used under hammer action to penetrate hard surfaces. This causes the bulk material to be pulverized as the drill travels through the radioactive media efficiently transmitting to the sampling unit a representative sample of powdered bulk material. The profiling equipment is designed to sequentially collect all material from the hole. The bulk material samples are continuously retrieved by use of a specially designed vacuumed sample retrieval unit that prevents cross contamination of the clean retrieved samples. No circulation medium is required with this profiling process; therefore, the only by-product from drilling is the sample. The data quality, quantity, and representativeness may be used to produce an activity profile from the hot spot surface into the bulk building material. The activity data obtained during the profiling process is reduced and transferred to building drawings as part of a detailed report of the radiological problem. This activity profile may then be expanded to ultimately characterize the facility and expedite waste segregation and facility closure at a reduced cost and risk

  17. Microscopic observation of bulking sludge formation and measures to fight it in activated sludge systems; Mikroskopische Betrachtung der Blaehschlammbildung und Massnahmen zur Bekaempfung in Belebungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Heine, W.; Sekoulov, I.; Burkhardt, H.; Behrendt, J. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Arbeitsbereich Abwasserwirtschaft

    1999-07-01

    The available results clearly show the suitability of digital microscopic image analysis for early detection of threatening bulking sludge events. Recognizing imminent bulking sludge events early on permits countering them effectively with simple and unspecific means. (orig.) [German] Die bisher erzielten Ergebnisse zeigen deutlich die Eignung der digitalen mikroskopischen Bildanalyse zur Frueherkennung drohender Blaehschlammereignisse. Wird ein drohendes Blaehschlammereignis fruehzeitig erkannt, so ist eine effektive Blaehschlammbekaempfung mit einfachen und unspezifischen Massnahmen moeglich. (orig.)

  18. Proton irradiation parameters and chemical separation procedure for the bulk production of high-specific-activity {sup 186g}Re using WO{sub 3} targets

    Energy Technology Data Exchange (ETDEWEB)

    Fassbender, M.E.; Ballard, B.; Birnbaum, E.R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.] [and others

    2013-08-01

    Rhenium-186g (T{sub 1/2} = 89.2 h) is a {beta}{sup -} emitter suitable for therapeutic applications. Current production methods rely on reactor production via {sup 185}Re(n,{gamma}) which results in low specific activities, thereby limiting its use. Production by p,d activation of enriched {sup 186}W results in a {sup 186g}Re product with a higher specific activity, allowing it to be used for targeted therapy with limited receptors. A test target consisting of pressed, sintered {sup nat}WO{sub 3} was proton irradiated at Los Alamos (LANL-IPF) to evaluate product yield and impurities, irradiation parameters and wet chemical Re recovery for proof-of-concept for bulk production of {sup 186g}Re. We demonstrated isolation of {sup 186g}Re in 97% yield from irradiated {sup nat}WO{sub 3} targets within 12 h of end of bombardment (EOB) via an alkaline dissolution followed by anion exchange. The recovery process has potential for automation, and WO{sub 3} can be easily recycled for recurrent irradiations. A {sup 186g}Re batch yield of 42.7 {+-} 2.2 {mu}Ci/{mu}Ah or 439 {+-} 23 MBq/C was obtained after 24 h in an 18.5 {mu}A proton beam. The target entrance energy was determined to be 15.6 MeV. The specific activity of {sup 186g}Re at EOB was measured to be 1.9 kCi (70.3 TBq) mmol{sup -1}, which agrees well with the result of a previous {sup 185,186m}Re co-production EMPIRE and TALYS modeling study assuming similar conditions. Utilizing enriched {sup 186}WO{sub 3}, we anticipate that a proton beam of 250 {mu}A for 24 h will provide batch yields of 256 mCi (9.5 GBq) of {sup 186g}Re at EOB with specific activities even higher than 1.9 kCi (70.3 TBq) mmol{sup -1}, suitable for therapy applications. (orig.)

  19. 19 CFR 151.24 - Unlading facilities for bulk sugar.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Unlading facilities for bulk sugar. 151.24 Section... OF THE TREASURY (CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Sugars, Sirups, and Molasses § 151.24 Unlading facilities for bulk sugar. When dutiable sugar is to be imported in bulk, a full...

  20. The development of neutron activation, sample transportation and γ-ray counting routine system for numbers of geological samples

    International Nuclear Information System (INIS)

    Shibata Shin-nosuke; Tanaka, Tsuyoshi; Minami, Masayo

    2001-01-01

    A new gamma-ray counting and data processing system for non-destructive neutron activation analysis has been set up in Radioisotope Center in Nagoya University. The system carry out gamma-ray counting, sample change and data processing automatically, and is able to keep us away from parts of complicated operations in INAA. In this study, we have arranged simple analytical procedure that makes practical works easier than previous. The concrete flow is described from the reparation of powder rock samples to gamma-ray counting and data processing by the new INAA system. Then it is run over that the analyses used two Geological Survey of Japan rock reference samples JB-1a and JG-1a in order to evaluate how the new analytical procedure give any speediness and accuracy for analyses of geological materials. Two United States Geological Survey reference samples BCR-1 and G-2 used as the standard respectively. Twenty two elements for JB-1a and 25 elements for JG-1a were analyzed, the uncertainty are <5% for Na, Sc, Fe, Co, La, Ce, Sm, Eu, Yb, Lu, Hf, Ta and Th, and of <10% for Cr, Zn, Cs, Ba, Nd, Tb and U. This system will enable us to analyze more than 1500 geologic samples per year. (author)

  1. Superductile bulk metallic glass

    International Nuclear Information System (INIS)

    Yao, K.F.; Ruan, F.; Yang, Y.Q.; Chen, N.

    2006-01-01

    Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<2%) at room temperature. We report a newly developed Pd-Si binary bulk metallic glass, which exhibits a uniform plastic deformation and a large plastic engineering strain of 82% and a plastic true strain of 170%, together with initial strain hardening, slight strain softening and final strain hardening characteristics. The uniform shear deformation and the ultrahigh plasticity are mainly attributed to strain hardening, which results from the nanoscale inhomogeneity due to liquid phase separation. The formed nanoscale inhomogeneity will hinder, deflect, and bifurcate the propagation of shear bands

  2. REECo activities and sample logistics in support of the Nevada Applied Ecology Group

    International Nuclear Information System (INIS)

    Wireman, D.L.; Rosenberry, C.E. Jr.

    1975-01-01

    Activities and sample logistics of Reynolds Electrical and Engineering Co., Inc. (REECo), in support of the Nevada Applied Ecology Group (NAEG), are discussed in this summary report. Activities include the collection, preparation, and shipment of samples of soils, vegetation, and small animals collected at Pu-contaminated areas of the Nevada Test Site and Tonopah Test Range. (CH)

  3. Correction for sample self-absorption in activity determination by gamma spectrometry

    International Nuclear Information System (INIS)

    Galloway, R.B.

    1991-01-01

    Gamma ray spectrometry is a convenient method of determining the activity of the radioactive components in environmental samples. Commonly samples vary in gamma absorption or differ in absorption from the calibration standards available, so that accurate correction for self-absorption in the sample is essential. A versatile correction procedure is described. (orig.)

  4. Activation analysis of gold in geological samples (Paper No. RA-24)

    International Nuclear Information System (INIS)

    Das, N.R.; Bhattacharyya, S.N.

    1990-02-01

    The technique of neutron activation analysis (NAA) has been applied to study the distribution of gold in some geological samples. Traces of gold in the samples were preconcentrated in a solid matrix through a chemical procedure involving solvent extraction using MIBK and coprecipitation with PbS. Gold contents in the samples as determined by NAA vary from ppb to ppm levels. (author)

  5. Determination of the neutron activation profile of core drill samples by gamma-ray spectrometry.

    Science.gov (United States)

    Gurau, D; Boden, S; Sima, O; Stanga, D

    2018-04-01

    This paper provides guidance for determining the neutron activation profile of core drill samples taken from the biological shield of nuclear reactors using gamma spectrometry measurements. Thus, it provides guidance for selecting a model of the right form to fit data and using least squares methods for model fitting. The activity profiles of two core samples taken from the biological shield of a nuclear reactor were determined. The effective activation depth and the total activity of core samples along with their uncertainties were computed by Monte Carlo simulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Auctioning Bulk Mobile Messages

    NARCIS (Netherlands)

    S. Meij (Simon); L-F. Pau (Louis-François); H.W.G.M. van Heck (Eric)

    2003-01-01

    textabstractThe search for enablers of continued growth of SMS traffic, as well as the take-off of the more diversified MMS message contents, open up for enterprises the potential of bulk use of mobile messaging , instead of essentially one-by-one use. In parallel, such enterprises or value added

  7. Diffusion or bulk flow

    DEFF Research Database (Denmark)

    Schulz, Alexander

    2015-01-01

    is currently matter of discussion, called passive symplasmic loading. Based on the limited material available, this review compares the different loading modes and suggests that diffusion is the driving force in apoplasmic loaders, while bulk flow plays an increasing role in plants having a continuous...

  8. Ferromagnetic bulk glassy alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Makino, Akihiro; Mizushima, Takao

    2000-01-01

    This paper deals with the review on the formation, thermal stability and magnetic properties of the Fe-based bulk glassy alloys in as-cast bulk and melt-spun ribbon forms. A large supercooled liquid region over 50 K before crystallization was obtained in Fe-(Al, Ga)-(P, C, B, Si), Fe-(Cr, Mo, Nb)-(Al, Ga)-(P, C, B) and (Fe, Co, Ni)-Zr-M-B (M=Ti, Hf, V, Nb, Ta, Cr, Mo and W) systems and bulk glassy alloys were produced in a thickness range below 2 mm for the Fe-(Al, Ga)-(P, C, B, Si) system and 6 mm for the Fe-Co-(Zr, Nb, Ta)-(Mo, W)-B system by copper-mold casting. The ring-shaped glassy Fe-(Al, Ga)-(P, C, B, Si) alloys exhibit much better soft magnetic properties as compared with the ring-shaped alloy made from the melt-spun ribbon because of the formation of the unique domain structure. The good combination of high glass-forming ability and good soft magnetic properties indicates the possibility of future development as a new bulk glassy magnetic material

  9. Determination of mercury in biologycal samples by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Suc, N.V.

    1989-01-01

    The radiochemical neutron activation analysis was applied to determine contents of mercury in biological samples. Samples were digested in mixing of H 2 SO 4 and HNO 3 acid. After extraction of mercury by Ni-Ditiodietylphosphoric acid in carbontetrachloride, mercury was back extracted by 5% KI solution. Contents of mercury from five samples of fish was determined by this method. The accuracy of the method was checked by comparing it with NBS standard samples and results are good agreement

  10. Determination of Magnesium in Needle Biopsy Samples of Muscle Tissue by Means of Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D; Sjoeberg, H E

    1964-07-15

    Magnesium has been determined by means of neutron-activation analysis in needle biopsy samples of the order of magnitude 1 mg dry weight. The procedure applied was to extract the Mg-27 activity from irradiated muscle tissue with concentrated hydrochloric acid followed by a fast hydroxide precipitation and gamma-spectrometric measurements. The Mg activity was recovered in the muscle tissue samples to (97 {+-} 2) per cent. The sensitivity for the magnesium determination is estimated as 0.3 {mu}g.

  11. The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

    Science.gov (United States)

    Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

    2016-04-01

    Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

  12. The Chemical Characterization of Nigerian Propolis samples and Their Activity Against Trypanosoma brucei.

    Science.gov (United States)

    Omar, Ruwida; Igoli, John O; Zhang, Tong; Gray, Alexander I; Ebiloma, Godwin U; Clements, Carol J; Fearnley, James; Edrada Ebel, RuAngeli; Paget, Tim; de Koning, Harry P; Watson, David G

    2017-04-19

    Profiling of extracts from twelve propolis samples collected from eight regions in Nigeria was carried out using high performance liquid chromatography (LC) coupled with evaporative light scattering (ELSD), ultraviolet detection (UV) and mass spectrometry (MS), gas chromatography mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). Principal component analysis (PCA) of the processed LC-MS data demonstrated the varying chemical composition of the samples. Most of the samples were active against Trypanosoma b. brucei with the highest activity being in the samples from Southern Nigeria. The more active samples were fractionated in order to isolate the component(s) responsible for their activity using medium pressure liquid chromatography (MPLC). Three xanthones, 1,3,7-trihydroxy-2,8-di-(3-methylbut-2-enyl)xanthone, 1,3,7-trihydroxy-4,8-di-(3-methylbut-2-enyl)xanthone a previously undescribed xanthone and three triterpenes: ambonic acid, mangiferonic acid and a mixture of α-amyrin with mangiferonic acid (1:3) were isolated and characterised by NMR and LC-MS. These compounds all displayed strong inhibitory activity against T.b. brucei but none of them had higher activity than the crude extracts. Partial least squares (PLS) modelling of the anti-trypanosomal activity of the sample extracts using the LC-MS data indicated that high activity in the extracts, as judged from LCMS 2 data, could be correlated to denticulatain isomers in the extracts.

  13. Large Sample Neutron Activation Analysis: A Challenge in Cultural Heritage Studies

    International Nuclear Information System (INIS)

    Stamatelatos, I.E.; Tzika, F.

    2007-01-01

    Large sample neutron activation analysis compliments and significantly extends the analytical tools available for cultural heritage and authentication studies providing unique applications of non-destructive, multi-element analysis of materials that are too precious to damage for sampling purposes, representative sampling of heterogeneous materials or even analysis of whole objects. In this work, correction factors for neutron self-shielding, gamma-ray attenuation and volume distribution of the activity in large volume samples composed of iron and ceramic material were derived. Moreover, the effect of inhomogeneity on the accuracy of the technique was examined

  14. Shielding design of highly activated sample storage at reactor TRIGA PUSPATI

    International Nuclear Information System (INIS)

    Naim Syauqi Hamzah; Julia Abdul Karim; Mohamad Hairie Rabir; Muhd Husamuddin Abdul Khalil; Mohd Amin Sharifuldin Salleh

    2010-01-01

    Radiation protection has always been one of the most important things considered in Reaktor Triga PUSPATI (RTP) management. Currently, demands on sample activation were increased from variety of applicant in different research field area. Radiological hazard may occur if the samples evaluation done were misjudge or miscalculated. At present, there is no appropriate storage for highly activated samples. For that purpose, special irradiated samples storage box should be provided in order to segregate highly activated samples that produce high dose level and typical activated samples that produce lower dose level (1 - 2 mR/ hr). In this study, thickness required by common shielding material such as lead and concrete to reduce highly activated radiotracer sample (potassium bromide) with initial exposure dose of 5 R/ hr to background level (0.05 mR/ hr) were determined. Analyses were done using several methods including conventional shielding equation, half value layer calculation and Micro shield computer code. Design of new irradiated samples storage box for RTP that capable to contain high level gamma radioactivity were then proposed. (author)

  15. Characterisation of bulk solids

    Energy Technology Data Exchange (ETDEWEB)

    D. McGlinchey [Glasgow Caledonian University, Glasgow (United Kingdom). Centre for Industrial Bulk Solids Handling

    2005-07-01

    Handling of powders and bulk solids is a critical industrial technology across a broad spectrum of industries, including minerals processing. With contributions from leading authors in their respective fields, this book provides the reader with a sound understanding of the techniques, importance and application of particulate materials characterisation. It covers the fundamental characteristics of individual particles and bulk particulate materials, and includes discussion of a wide range of measurement techniques, and the use of material characteristics in design and industrial practice. Contents: Characterising particle properties; Powder mechanics and rheology; Characterisation for hopper and stockpile design; Fluidization behaviour; Characterisation for pneumatic conveyor design; Explosiblility; 'Designer' particle characteristics; Current industrial practice; and Future trends. 130 ills.

  16. Investigation of donor-acceptor copolymer films and their blends with fullerene in the active layers of bulk heterojunction solar cells by Raman microspectroscopy

    Czech Academy of Sciences Publication Activity Database

    Cimrová, Věra; Morávková, Zuzana; Pokorná, Veronika; Výprachtický, Drahomír

    2017-01-01

    Roč. 47, August (2017), s. 194-199 ISSN 1566-1199 R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : conjugated polymers * low-band gap * bulk heterojunction Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.399, year: 2016

  17. Micromegas in a bulk

    International Nuclear Information System (INIS)

    Giomataris, I.; De Oliveira, R.; Andriamonje, S.; Aune, S.; Charpak, G.; Colas, P.; Fanourakis, G.; Ferrer, E.; Giganon, A.; Rebourgeard, Ph.; Salin, P.

    2006-01-01

    In this paper, we present a novel way to manufacture the bulk Micromegas detector. A simple process based on the Printed Circuit Board (PCB) technology is employed to produce the entire sensitive detector. Such a fabrication process could be extended to very large area detectors made by the industry. The low cost fabrication together with the robustness of the electrode materials will make it attractive for several applications ranging from particle physics and astrophysics to medicine

  18. Seasonal Variation, Chemical Composition and Antioxidant Activity of Brazilian Propolis Samples

    Directory of Open Access Journals (Sweden)

    Érica Weinstein Teixeira

    2010-01-01

    Full Text Available Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil were determined. Total phenolic contents were determined by the Folin–Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being α- and β-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis.

  19. Application of neutron activation analysis to trace elements determinations in lung samples

    International Nuclear Information System (INIS)

    Rogero, S.O.

    1991-01-01

    The purpose of this work was to apply the instrumental neutron activation analysis method to determine trace elements in lung samples from smokers and non smokers. Samples of lung tissues and lymph nodes from pulmonary hilum analyzed were collected from autopsies by researchers from Faculdade de Medicina da USP. (author)

  20. Absolute activity determinations on large volume geological samples independent of self-absorption effects

    International Nuclear Information System (INIS)

    Wilson, W.E.

    1980-01-01

    This paper describes a method for measuring the absolute activity of large volume samples by γ-spectroscopy independent of self-absorption effects using Ge detectors. The method yields accurate matrix independent results at the expense of replicative counting of the unknown sample. (orig./HP)

  1. Automatic sample changer control software for automation of neutron activation analysis process in Malaysian Nuclear Agency

    Science.gov (United States)

    Yussup, N.; Ibrahim, M. M.; Rahman, N. A. A.; Mokhtar, M.; Salim, N. A. A.; Soh@Shaari, S. C.; Azman, A.; Lombigit, L.; Azman, A.; Omar, S. A.

    2018-01-01

    Most of the procedures in neutron activation analysis (NAA) process that has been established in Malaysian Nuclear Agency (Nuclear Malaysia) since 1980s were performed manually. These manual procedures carried out by the NAA laboratory personnel are time consuming and inefficient especially for sample counting and measurement process. The sample needs to be changed and the measurement software needs to be setup for every one hour counting time. Both of these procedures are performed manually for every sample. Hence, an automatic sample changer system (ASC) that consists of hardware and software is developed to automate sample counting process for up to 30 samples consecutively. This paper describes the ASC control software for NAA process which is designed and developed to control the ASC hardware and call GammaVision software for sample measurement. The software is developed by using National Instrument LabVIEW development package.

  2. Determination of gold and silver in geological standard samples MGI by instrument neutron activation analysis

    International Nuclear Information System (INIS)

    Lu Huijiuan; Zhou; Yunlu

    1987-01-01

    Gold and silver in geological standard samples MGI were determined by instrument neutron activation analysis. The various interferences of nuclides were considered. Corrected factors of the geometry in different positions have been determined. Using the geological standard sample MGM and radiochemical separation neutron activation method as reference, the reliability of this method is proved. Gold content in samples is 0.4-0.009 g/t, silver content is 9-0.3 g/t. Standard deviation is less than 3.5%, the precision of the measurement is 4.8-11.6%

  3. Surface barrier and bulk pinning in MgB$_2$ superconductor

    OpenAIRE

    Pissas, M.; Moraitakis, E.; Stamopoulos, D.; Papavassiliou, G.; Psycharis, V.; Koutandos, S.

    2001-01-01

    We present a modified method of preparation of the new superconductor MgB$_2$. The polycrystalline samples were characterized using x-ray and magnetic measurements. The surface barriers control the isothermal magnetization loops in powder samples. In bulk as prepared samples we always observed symmetric magnetization loops indicative of the presence of a bulk pinning mechanism. Magnetic relaxation measurements in the bulk sample reveal a crossover of surface barrier to bulk pinning.

  4. Reinforcing Sampling Distributions through a Randomization-Based Activity for Introducing ANOVA

    Science.gov (United States)

    Taylor, Laura; Doehler, Kirsten

    2015-01-01

    This paper examines the use of a randomization-based activity to introduce the ANOVA F-test to students. The two main goals of this activity are to successfully teach students to comprehend ANOVA F-tests and to increase student comprehension of sampling distributions. Four sections of students in an advanced introductory statistics course…

  5. Local activation time sampling density for atrial tachycardia contact mapping: how much is enough?

    Science.gov (United States)

    Williams, Steven E; Harrison, James L; Chubb, Henry; Whitaker, John; Kiedrowicz, Radek; Rinaldi, Christopher A; Cooklin, Michael; Wright, Matthew; Niederer, Steven; O'Neill, Mark D

    2018-02-01

    Local activation time (LAT) mapping forms the cornerstone of atrial tachycardia diagnosis. Although anatomic and positional accuracy of electroanatomic mapping (EAM) systems have been validated, the effect of electrode sampling density on LAT map reconstruction is not known. Here, we study the effect of chamber geometry and activation complexity on optimal LAT sampling density using a combined in silico and in vivo approach. In vivo 21 atrial tachycardia maps were studied in three groups: (1) focal activation, (2) macro-re-entry, and (3) localized re-entry. In silico activation was simulated on a 4×4cm atrial monolayer, sampled randomly at 0.25-10 points/cm2 and used to re-interpolate LAT maps. Activation patterns were studied in the geometrically simple porcine right atrium (RA) and complex human left atrium (LA). Activation complexity was introduced into the porcine RA by incomplete inter-caval linear ablation. In all cases, optimal sampling density was defined as the highest density resulting in minimal further error reduction in the re-interpolated maps. Optimal sampling densities for LA tachycardias were 0.67 ± 0.17 points/cm2 (focal activation), 1.05 ± 0.32 points/cm2 (macro-re-entry) and 1.23 ± 0.26 points/cm2 (localized re-entry), P = 0.0031. Increasing activation complexity was associated with increased optimal sampling density both in silico (focal activation 1.09 ± 0.14 points/cm2; re-entry 1.44 ± 0.49 points/cm2; spiral-wave 1.50 ± 0.34 points/cm2, P density (0.61 ± 0.22 points/cm2 vs. 1.0 ± 0.34 points/cm2, P = 0.0015). Optimal sampling densities can be identified to maximize diagnostic yield of LAT maps. Greater sampling density is required to correctly reveal complex activation and represent activation across complex geometries. Overall, the optimal sampling density for LAT map interpolation defined in this study was ∼1.0-1.5 points/cm2. Published on behalf of the European Society of

  6. Determination of uranium and thorium in rock samples from Harargaj Anticline by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Rahman, M.; Molla, N.I.; Sharif, A.K.M.; Basunia, S.; Islam, S.; Miah, R.U.; Hossain, S.M.; Chowdhury, M.I.; Bhuiyan, A.D.; Stegnar, P.

    1993-01-01

    Uranium and thorium were determined in geological materials such as radioactive rock samples collected from the Harargaj Anticline in Moulavi Bazar. The pure instrumental neutron activation analysis (INAA) technique was used in qualitative and quantitative analysis of the rock samples for U and Th. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of the order of 10 12 n*cm -2 *s -1 using the TRIGA MARK II research reactor facility at the AERE, Savar, Dhaka. After activation the samples were subjected to γ-ray spectrometry using a high purity germanium detection system. As a result of the analysis, U and Th could be determined. The data are consistent with the values reported by the ground radiometric survey group for some of the samples. (author) 7 refs.; 1 fig.; 2 tabs

  7. Comparison of uranium and radium isotopes activities in some wells and thermal springs samples in Morroco

    International Nuclear Information System (INIS)

    Hakam, O.K.; Choukri, A.; Reyss, J.L.; Lferde, M.

    2000-01-01

    Activities and activity ratios of uranium and radium isotopes ( 234 U, 238 U, 226 Ra, 228 Ra, 234 U/ 238 U, 226 Ra/ 238 U, 228 Ra/ 226 Ra) have been determined, for the first time in Morocco, for 15 well water samples and 12 spring water samples. The obtained results show that, unlike well waters, the thermal spring waters present relatively low 238 U activities and elevated 226 Ra activities and 234 U/ 238 U activity ratios. Uranium and radium activities are similar to those published for other non polluting regions of the world, they are inferior to the Maximum Contaminant Levels and don't present any risk for public health in Morocco. (author) [fr

  8. Spatiotemporally Representative and Cost-Efficient Sampling Design for Validation Activities in Wanglang Experimental Site

    Directory of Open Access Journals (Sweden)

    Gaofei Yin

    2017-11-01

    Full Text Available Spatiotemporally representative Elementary Sampling Units (ESUs are required for capturing the temporal variations in surface spatial heterogeneity through field measurements. Since inaccessibility often coexists with heterogeneity, a cost-efficient sampling design is mandatory. We proposed a sampling strategy to generate spatiotemporally representative and cost-efficient ESUs based on the conditioned Latin hypercube sampling scheme. The proposed strategy was constrained by multi-temporal Normalized Difference Vegetation Index (NDVI imagery, and the ESUs were limited within a sampling feasible region established based on accessibility criteria. A novel criterion based on the Overlapping Area (OA between the NDVI frequency distribution histogram from the sampled ESUs and that from the entire study area was used to assess the sampling efficiency. A case study in Wanglang National Nature Reserve in China showed that the proposed strategy improves the spatiotemporally representativeness of sampling (mean annual OA = 74.7% compared to the single-temporally constrained (OA = 68.7% and the random sampling (OA = 63.1% strategies. The introduction of the feasible region constraint significantly reduces in-situ labour-intensive characterization necessities at expenses of about 9% loss in the spatiotemporal representativeness of the sampling. Our study will support the validation activities in Wanglang experimental site providing a benchmark for locating the nodes of automatic observation systems (e.g., LAINet which need a spatially distributed and temporally fixed sampling design.

  9. Accounting for the thermal neutron flux depression in voluminous samples for instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Overwater, R.M.W.; Hoogenboom, J.E.

    1994-01-01

    At the Delft University of Technology Interfaculty Reactor Institute, a facility has been installed to irradiate cylindrical samples with diameters up to 15 cm and weights up to 50 kg for instrumental neutron activation analysis (INAA) purposes. To be able to do quantitative INAA on voluminous samples, it is necessary to correct for gamma-ray absorption, gamma-ray scattering, neutron absorption, and neutron scattering in the sample. The neutron absorption and the neutron scattering are discussed. An analytical solution is obtained for the diffusion equation in the geometry of the irradiation facility. For samples with known composition, the neutron flux--as a function of position in the sample--can be calculated directly. Those of unknown composition require additional flux measurements on which least-squares fitting must be done to obtain both the thermal neutron diffusion coefficient D s and the diffusion length L s of the sample. Experiments are performed to test the theory

  10. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    OpenAIRE

    Koop, G.; Dik, N.; Nielen, M.; Lipman, L.J.A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms, 3 bulk milk samples were collected at intervals of 2 wk. The samples were cultured for SPC, coliform count, and staphylococcal count and for the presence of Staphylococcus aureus. Furthermore, SCC ...

  11. Active Search on Carcasses versus Pitfall Traps: a Comparison of Sampling Methods.

    Science.gov (United States)

    Zanetti, N I; Camina, R; Visciarelli, E C; Centeno, N D

    2016-04-01

    The study of insect succession in cadavers and the classification of arthropods have mostly been done by placing a carcass in a cage, protected from vertebrate scavengers, which is then visited periodically. An alternative is to use specific traps. Few studies on carrion ecology and forensic entomology involving the carcasses of large vertebrates have employed pitfall traps. The aims of this study were to compare both sampling methods (active search on a carcass and pitfall trapping) for each coleopteran family, and to establish whether there is a discrepancy (underestimation and/or overestimation) in the presence of each family by either method. A great discrepancy was found for almost all families with some of them being more abundant in samples obtained through active search on carcasses and others in samples from traps, whereas two families did not show any bias towards a given sampling method. The fact that families may be underestimated or overestimated by the type of sampling technique highlights the importance of combining both methods, active search on carcasses and pitfall traps, in order to obtain more complete information on decomposition, carrion habitat and cadaveric families or species. Furthermore, a hypothesis advanced on the reasons for the underestimation by either sampling method showing biases towards certain families. Information about the sampling techniques indicating which would be more appropriate to detect or find a particular family is provided.

  12. Phosphatase Activity of Microbial Populations in Different Milk Samples in Relation to Protein and Carbohydrate Content

    Directory of Open Access Journals (Sweden)

    Sosanka Protim SANDILYA

    2014-12-01

    Full Text Available Cattle milk is a rich source of protein, carbohydrate, vitamins, minerals and all other major and micro nutrients. At a moderate pH, milk is an excellent media for the growth of microbes and thus, intake of raw milk is precarious. In this study, attempt was made for a qualitative study of eight raw milk samples of different varieties of cow and goat milk, collected from Jorhat district of Assam, India, on the basis of nutritional value and microbial population. The highest microbial population was found in the milk collected from cross hybrid variety of cow, whereas microbial contamination was the least in Jersey cow milk. Samples of C1 (Jersey cow variety showed presence of the highest amount of protein and carbohydrate content as compared to the others. Almost all the milk samples showed positive acid and alkaline phosphatase activity. Maximum acid phosphatase activity was observed in cross hybrid cow milk, whereas local cow milk exhibited the highest alkaline phosphatase activity. Phosphatase activity did not show any co-relationship with microbial population of the milk samples. Similarly, the protein and carbohydrate content of the samples did not have any significant impact on both acid and alkaline phosphatase activity.

  13. Development and installation of an automatic sample changer for neutron activation analysis

    International Nuclear Information System (INIS)

    Domienikan, Claudio; Lapolli, Andre L.; Schoueri, Roberto M.; Moreira, Edson G.; Vasconcellos, Marina B.A.

    2013-01-01

    A Programmable and Automatic Sample Changer was built and installed at the Neutron Activation Analysis Laboratory of the Nuclear and Energy Research Institute - IPEN-CNEN/SP, Brazil. This Automatic Sample Changer allows the fully automated measurement of up to 25 samples in one run. Basically it consists of an electronic circuit and C++ program that controls the positioning of a sample holder in two axes of motion (X and Y). Each sample is transported and positioned, one by one, inside the shielding coupled to a high-purity germanium (HPGe) radiation detector. A Canberra DSA-1000 Multichannel Analyzer coupled to the Genie 2000 software performs the data acquisition for analysis of the samples. When the counting is finished the results are saved in a hard disk of a PC computer. The sample is brought back by the sample holder to its initial position, and the next sample is carried to the shielding. The Sample Changer was designed and constructed at IPEN-CNEN/SP by employing national components and expertise. (author)

  14. Behavioural sampling techniques and activity pattern of Indian Pangolin Manis crassicaudata (Mammalia: Manidae in captivity

    Directory of Open Access Journals (Sweden)

    R.K. Mohapatra

    2013-12-01

    Full Text Available The study presents data on six Indian Pangolins Manis crassicaudata observed in captivity at the Pangolin Conservation Breeding Centre, Nandankanan, Odisha, India over 1377 hours of video recordings for each pangolin between 1500hr and 0800hr on 81 consecutive observational days. Video recordings were made through digital systems assisted by infrared enabled CCTV cameras. The data highlights patterns relate to 12 different behaviour and enclosure utilization. Different interval periods for sampling of instantaneous behaviour from video recordings have been evaluated to develop optimal study methods for the future. The activity budgets of pangolins displayed natural patterns of nocturnal activity with a peak between 20:00-21:00 hr. When out of their burrow, they spent about 59% of the time walking in the enclosure, and 14% of the time feeding. The repeatability of the behaviours has a significant negative correlation with the mean time spent in that behaviour. Focal behavioural samples significantly correlated with instantaneous samples up to 15 minutes interval. The correlation values gradually decreased with the increase in sampling interval. The results indicate that results obtained from focal sampling and instantaneous sampling with relatively shorter intervals (=5 minutes are about equally reliable. The study suggests use of focal sampling, instead of instantaneous sampling to record behaviour relating to social interactions.

  15. Synthesis of Bulk Superconducting Magnesium Diboride

    Directory of Open Access Journals (Sweden)

    Margie Olbinado

    2002-06-01

    Full Text Available Bulk polycrystalline superconducting magnesium diboride, MgB2, samples were successfully prepared via a one-step sintering program at 750°C, in pre Argon with a pressure of 1atm. Both electrical resistivity and magnetic susceptibility measurements confirmed the superconductivity of the material at 39K, with a transition width of 5K. The polycrystalline nature, granular morphology, and composition of the sintered bulk material were confirmed using X-ray diffractometry (XRD, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX.

  16. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel

    2015-01-01

    the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low......-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk...

  17. A simple method of correcting for variation of sample thickness in the determination of the activity of environmental samples by gamma spectrometry

    International Nuclear Information System (INIS)

    Galloway, R.B.

    1991-01-01

    Gamma ray spectrometry is a well established method of determining the activity of radioactive components in environmental samples. It is usual to maintain precisely the same counting geometry in measurements on samples under investigation as in the calibration measurements on standard materials of known activity, thus avoiding perceived uncertainties and complications in correcting for changes in counting geometry. However this may not always be convenient if, as on some occasions, only a small quantity of sample material is available for analysis. A procedure which avoids re-calibration for each sample size is described and is shown to be simple to use without significantly reducing the accuracy of measurement of the activity of typical environmental samples. The correction procedure relates to the use of cylindrical samples at a constant distance from the detector, the samples all having the same diameter but various thicknesses being permissible. (author)

  18. Immobilization of the Enzyme Glucose Oxidase on Both Bulk and Porous SiO2 Surfaces

    Directory of Open Access Journals (Sweden)

    Fulvia Sinatra

    2008-09-01

    Full Text Available Silicon dioxide surfaces, both bulk and porous, were used to anchor the enzyme glucose oxidase. The immobilization protocol was optimized and the samples characterized using X-ray Photoelectron Spectroscopy, Energy Dispersive X-rays coupled to scanning electron microscopy and enzymatic activity measurements. We show that a uniform layer was obtained by activating the oxide before immobilization. X-ray Photoelectron Spectroscopy measurements carried out on bulk oxide showed that the silicon substrate signal was fully screened after the enzyme deposition showing the absence of uncovered surface regions. The enzyme presence was detected monitoring both the C 1s and N 1s signals. Finally, enzymatic activity measurements confirmed that the glucose oxidase activity was preserved after immobilization and maintained after three months of shelf life if the sample was properly stored. The importance of using porous silicon oxide to maximize the surface area was also evidenced.

  19. Modern Trends in Neutron Activation Analysis. Applications to some African Environmental Samples

    International Nuclear Information System (INIS)

    Hassan, A.M.

    2009-01-01

    This review covers the results of several published articles which deal with the modern trends in neutron activation analysis techniques using some of African research reactors for some environmental samples. The samples used have been collected from different areas in Egypt, South Africa, Ghana, Morocco, Nigeria, and Algeria. The neutron irradiation facilities and the advanced detection systems in each country are outlined. The prompt and delayed gamma-rays emitted due to neutron capture have been applied for investigation of the elemental constituents of such samples. Covered applications include exploration, mining, industrial environment, pollution of air, foodstuffs, soils and irrigation water samples. Some of the developed software programmes as well as the modern methods of data analysis are presented. The thermal and epithermal neutron activation analysis techniques have been applied for estimation of major, minor and trace elements in each material. Some of these data are presented with several comments.

  20. Determination of 137Cs activities in soil samples from east and south Marmara region, Turkey

    International Nuclear Information System (INIS)

    Kilic, Oe.; Belivermis, M.; Cotuk, Y.; Coskun, M.; Cayir, A.; Kuecer, R.

    2006-01-01

    Activity concentrations of 1 37Cs, 4 0K and physico-chemical parameters of soil samples collected from 99 sampling stations in the east and south of Marmara Region of Turkey were determined. The study region was divided into 20 x 20 km grids and soil samples collected randomly in each square from 0-5 cm surface layer. Activities were measured by means of multichannel gamma analyser provided with high purity germanium detector. Relations among 1 37Cs concentrations and physico-chemical parameters of soils and climatic factors of the region were evaluated. Arc View GIS version 3.1 was used mapping of study area. Distribution of radionuclide concentrations in the region illustrated with contour maps using Surfer 8.0 for Windows. The range of activity concentrations of 1 37Cs and 4 0K were measured to be 0.92-153.72 and 69.24-1085.57 Bq/kg respectively

  1. Raman characterization of bulk ferromagnetic nanostructured graphite

    International Nuclear Information System (INIS)

    Pardo, Helena; Divine Khan, Ngwashi; Faccio, Ricardo; Araújo-Moreira, F.M.; Fernández-Werner, Luciana

    2012-01-01

    Raman spectroscopy was used to characterize bulk ferromagnetic graphite samples prepared by controlled oxidation of commercial pristine graphite powder. The G:D band intensity ratio, the shape and position of the 2D band and the presence of a band around 2950 cm -1 showed a high degree of disorder in the modified graphite sample, with a significant presence of exposed edges of graphitic planes as well as a high degree of attached hydrogen atoms.

  2. Analysis of medicinal plants and soil sample from Haridwar region by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Maharia, R.S.; Dutta, R.K.; Acharya, R.; Reddy, A.V.R.

    2009-01-01

    Samples of leaves and stems of four medicinal plants namely Kalmegh, Amaltas, Moalshri, and Arusa were analysed by Instrumental Neutron Activation Analysis. Soil from same location was analyzed. Though concentrations of many elements were determined in the plant samples, results of selected elements namely Na, K, Mn, Fe, Co, Cr, Zn and As are discussed in this paper. The results show that all medicinal plants analyzed have lower elemental contents except Zn compared to the soil. (author)

  3. Thermal activation of catalytic microjets in blood samples using microfluidic chips.

    Science.gov (United States)

    Soler, Lluís; Martínez-Cisneros, Cynthia; Swiersy, Anka; Sánchez, Samuel; Schmidt, Oliver G

    2013-11-21

    We demonstrate that catalytic microjet engines can out-swim high complex media composed of red blood cells and serum. Despite the challenge presented by the high viscosity of the solution at room temperature, the catalytic microjets can be activated at physiological temperature and, consequently, self-propel in diluted solutions of blood samples. We prove that these microjets self-propel in 10× diluted blood samples using microfluidic chips.

  4. Thermal activation of catalytic microjets in blood samples using microfluidic chips†

    Science.gov (United States)

    Soler, Lluís; Martínez-Cisneros, Cynthia; Swiersy, Anka; Sánchez, Samuel; Schmidt, Oliver G.

    2014-01-01

    We demonstrate that catalytic microjet engines can out-swim high complex media composed of red blood cells and serum. Despite the challenge presented by the high viscosity of the solution at room temperature, the catalytic microjets can be activated at physiological temperature and, consequently, self-propel in diluted solutions of blood samples. We prove that these microjets self-propel in 10× diluted blood samples using microfluidic chips. PMID:24089195

  5. Qualitative Elemental Analyses of a Meteorite Sample Found in Turkey by Photo-activation Analysis Method

    International Nuclear Information System (INIS)

    Ertugay, C; Boztosun, I; Ozmen, S F; Dapo, H

    2015-01-01

    In this paper, a meteorite sample provided from TÜBITAK National Observatory found in Turkey has been investigated by using a clinical linear accelerator that has endpoint energy of 18 MeV, and a high purity Germanium detector for qualitative elemental analysis within photo-activation analysis method. 21 nuclei ranging from 24Na to 149Nd have been identified in the meteorite sample. (paper)

  6. Neutron activation analysis for sulphur in coal samples and moisture content by gamma-ray transmission

    International Nuclear Information System (INIS)

    Selvi, S.

    1993-01-01

    A neutron activation analysis method is described for the determination of sulphur in coal samples by analysing the beta spectrum emitted from 32 P and 33 P following the reactions 32 S(n, p) 32 P and 33 S(n, p) 33 P using 252 Cf as a source of neutrons. The transmission of the combined gamma-rays emitted from three 137 Cs and three 241 Am sources is used to measure the water content of the coal samples. (author)

  7. Different methodologies in neutron activation to approach the full analysis of environmental and nutritional samples

    International Nuclear Information System (INIS)

    Freitas, M.C.; Dionisio, I.; Dung, H.M.

    2008-01-01

    Different methodologies of neutron activation analysis (NAA) are now available at the Technological and Nuclear Institute (Sacavem, Portugal), namely Compton suppression, epithermal activation, replicate and cyclic activation, and low energy photon measurement. Prompt gamma activation analysis (PGAA) will be implemented soon. Results by instrumental NAA and PGAA on environmental and nutritional samples are discussed herein, showing that PGAA - carried out at the Institute of Isotope Research (Budapest, Hungary) - brings about an effective input to assessing relevant elements. Sensitivity enhancement in NAA by Compton suppression is also illustrated. Through a judicious combination of methodologies, practically all elements of interest in pollution and nutrition terms can be determined. (author)

  8. Bulk muscles, loose cables.

    Science.gov (United States)

    Liyanage, Chamari R D G; Kodali, Venkata

    2014-10-17

    The accessibility and usage of body building supplements is on the rise with stronger internet marketing strategies by the industry. The dangers posed by the ingredients in them are underestimated. A healthy young man came to the emergency room with palpitations and feeling unwell. Initial history and clinical examination were non-contributory to find the cause. ECG showed atrial fibrillation. A detailed history for any over the counter or herbal medicine use confirmed that he was taking supplements to bulk muscle. One of the components in these supplements is yohimbine; the onset of symptoms coincided with the ingestion of this product and the patient is symptom free after stopping it. This report highlights the dangers to the public of consuming over the counter products with unknown ingredients and the consequential detrimental impact on health. 2014 BMJ Publishing Group Ltd.

  9. Feasibility studies on large sample neutron activation analysis using a low power research reactor

    International Nuclear Information System (INIS)

    Gyampo, O.

    2008-06-01

    Instrumental neutron activation analysis (INAA) using Ghana Research Reactor-1 (GHARR-1) can be directly applied to samples with masses in grams. Samples weights were in the range of 0.5g to 5g. Therefore, the representativity of the sample is improved as well as sensitivity. Irradiation of samples was done using a low power research reactor. The correction for the neutron self-shielding within the sample is determined from measurement of the neutron flux depression just outside the sample. Correction for gamma ray self-attenuation in the sample was performed via linear attenuation coefficients derived from transmission measurements. Quantitative and qualitative analysis of data were done using gamma ray spectrometry (HPGe detector). The results of this study on the possibilities of large sample NAA using a miniature neutron source reactor (MNSR) show clearly that the Ghana Research Reactor-1 (GHARR-1) at the National Nuclear Research Institute (NNRI) can be used for sample analyses up to 5 grams (5g) using the pneumatic transfer systems.

  10. The problem of large samples. An activation analysis study of electronic waste material

    International Nuclear Information System (INIS)

    Segebade, C.; Goerner, W.; Bode, P.

    2007-01-01

    Large-volume instrumental photon activation analysis (IPAA) was used for the investigation of shredded electronic waste material. Sample masses from 1 to 150 grams were analyzed to obtain an estimate of the minimum sample size to be taken to achieve a representativeness of the results which is satisfactory for a defined investigation task. Furthermore, the influence of irradiation and measurement parameters upon the quality of the analytical results were studied. Finally, the analytical data obtained from IPAA and instrumental neutron activation analysis (INAA), both carried out in a large-volume mode, were compared. Only parts of the values were found in satisfactory agreement. (author)

  11. Automation of Sample Transfer and Counting on Fast Neutron ActivationSystem

    International Nuclear Information System (INIS)

    Dewita; Budi-Santoso; Darsono

    2000-01-01

    The automation of sample transfer and counting were the transfer processof the sample to the activation and counting place which have been done byswitch (manually) previously, than being developed by automaticallyprogrammed logic instructions. The development was done by constructed theelectronics hardware and software for that communication. Transfer timemeasurement is on seconds and was done automatically with an error 1.6 ms.The counting and activation time were decided by the user on seconds andminutes, the execution error on minutes was 8.2 ms. This development systemwill be possible for measuring short half live elements and cyclic activationprocesses. (author)

  12. Determination of selenium in food matrices by replicate sample neutron activation analysis

    International Nuclear Information System (INIS)

    Ventura, M.G.; Freitas, M.C.; Ventura, M.G.; Pacheco, A.M.G.

    2009-01-01

    The replicate sample instrumental neutron activation method was optimized and used for the determination of selenium in foodstuffs. The method was reliable, yielding accurate results. Lower detections limits were obtained after each successive irradiation. Different irradiation conditions were used depending on the type of sample. For samples with higher selenium contents (meat, fish, eggs), the measured selenium in the first replicate is in all cases larger than the detection limit, but a better accuracy was obtained with a larger number of replicates (2-3 replicates). For samples with extremely low selenium contents (vegetable samples), at least seven replicates were necessary to obtain a concentration value two times larger than the detection limit. (author)

  13. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kasviki, K. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece); Stamatelatos, I.E. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece)], E-mail: ion@ipta.demokritos.gr; Yannakopoulou, E. [Institute of Physical Chemistry, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Papadopoulou, P. [Institute of Technology of Agricultural Products, NAGREF, Lycovrissi, Attikis 14123 (Greece); Kalef-Ezra, J. [Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece)

    2007-10-15

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv.

  14. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Kasviki, K.; Stamatelatos, I.E.; Yannakopoulou, E.; Papadopoulou, P.; Kalef-Ezra, J.

    2007-01-01

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv

  15. Neutron activation analysis of geological samples for gold and accessory elements power reactor

    International Nuclear Information System (INIS)

    Burmistrenko, Yu.N.; Medvedev, A.A.; Kovalenko, V.V.; Markov, A.V.

    1986-01-01

    Possibility of using a power reactor for neutron activation analysis to detect gold and accompanying elements in geological samples of a region was investigated. Specimens (gold-containing samples and standards) were irradiated in a spare channel for ionization chambers located outside the core in graphite reflector. Spectrometry was conducted with the help of a semiconducting detector with LP 4900 multichannel analizer. Sensitivity threshold for gold was (1-3)10 -6 % - (1-2)10 -5 %. It is shown that this method can be used not only for gold detection but for high-sensitive multielement analysis of geological samples

  16. Activation analysis of Al2O3 samples at the RB reactor

    International Nuclear Information System (INIS)

    Sokcic-Kostic, M.; Antic, D.; Pesic, M.

    1994-01-01

    Low flux activation analysis was successfully performed at the zero power RB reactor on a specific sample giving good results. For analysis of low concentration, isotopes must have cross sections of a few barns and periods of a few days with profitable disintegration schemes. This means irradiation of n x ∼ 10 min and flux n x 10 7 n/cm 2 s. The specific results of this and similar experiments provide information for industrial treatment of trace elements and sample analyses in different fields of research as well as food sample analysis

  17. Elemental analysis of soil and hair sample by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Quraishi, Shamshad Begum; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Yeoil; Kang, Sang Hoon; Lim, Jong Myoung; Cho, Hyun Je; Kim, Young Jin

    2004-03-01

    Myanmar soil sample was analyzed by using the instrumental neutron activation analysis. The elemental concentrations in the sample, altogether 34 elements, Al As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Ga, Gd, Hf, Ir, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Yb, Zn and Zr were determined. The concentration of 17 elements (Al, Au, Br, Ca, Cl, Cr, Cu, Co, Fe, Hg, K, Na, Mn, Mg, Sb, Se, Zn) in human hair samples were determined by INAA For quality control of analytical method, certified reference material was used

  18. Elemental analysis of soil and hair sample by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Quraishi, Shamshad Begum; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Yeoil; Kang, Sang Hoon; Lim, Jong Myoung; Cho, Hyun Je; Kim, Young Jin

    2004-03-01

    Myanmar soil sample was analyzed by using the instrumental neutron activation analysis. The elemental concentrations in the sample, altogether 34 elements, Al As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Ga, Gd, Hf, Ir, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Yb, Zn and Zr were determined. The concentration of 17 elements (Al, Au, Br, Ca, Cl, Cr, Cu, Co, Fe, Hg, K, Na, Mn, Mg, Sb, Se, Zn) in human hair samples were determined by INAA For quality control of analytical method, certified reference material was used.

  19. Nuclear techniques for bulk ore analysis and their application to quality control

    International Nuclear Information System (INIS)

    Holmes, R.J.

    1981-01-01

    Bulk analysis techniques developed for the mining industry in which analyses are obtained directly from 3-30kg ore samples or from ore on conveyor belts are outlined. They include the determination of iron in iron ores from backscattered gamma radiation, shale in sedimentary iron ores from natural gamma activity, iron from a thermal-neutron capture reaction, and aluminium from the thermal neutron activation reaction

  20. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  1. Determination of uranium and thorium by neutron activation analysis applied to fossil samples dating

    International Nuclear Information System (INIS)

    Ticianelli, Regina B.; Figueiredo, Ana Maria Graciano; Zahn, Guilherme S.; Kinoshita, Angela; Baffa, Oswaldo

    2011-01-01

    Electron Spin Resonance (ESR) dating is based on the fact that ionizing radiation can create stable free radicals in insulating materials, like tooth enamel and bones. The concentration of these radicals - determined by ESR - is a function of the dose deposed in the sample along the years. The accumulated dose of radiation, called Archaeological Dose, is produced by the exposition to environmental radiation provided by U, Th, K and cosmic rays. If the environmental dose rate in the site where the fossil sample is found is known, it is possible to convert this dose into the age of the sample. The annual dose rate coming from the radioactive elements present in the soil and in the sample itself can be calculated by determining the U, Th and K concentration. Therefore, the determination of the dose rate depends on the concentration of these main radioactive elements. Neutron Activation Analysis has the sensitivity and the accuracy necessary to determine U, Th and K with this objective. Depending on the composition of the sample, the determination of U and Th can be improved irradiating the sample inside a Cd capsule, reducing the thermal neutron incidence on the sample and, therefore, diminishing the activation of possible interfering nuclides. In this study the optimal irradiation and counting conditions were established for U and Th determination in fossil teeth and soil. (author)

  2. Development of digital gamma-activation autoradiography for analysis of samples of large area

    International Nuclear Information System (INIS)

    Kolotov, V.P.; Grozdov, D.S.; Dogadkin, N.N.; Korobkov, V.I.

    2011-01-01

    Gamma-activation autoradiography is a prospective method for screening detection of inclusions of precious metals in geochemical samples. Its characteristics allow analysis of thin sections of large size (tens of cm2), that favourably distinguishes it among the other methods for local analysis. At the same time, the activating field of the accelerator bremsstrahlung, displays a sharp intensity decrease relative to the distance along the axis. A method for activation dose ''equalization'' during irradiation of the large size thin sections has been developed. The method is based on the usage of a hardware-software system. This includes a device for moving the sample during the irradiation, a program for computer modelling of the acquired activating dose for the chosen kinematics of the sample movement and a program for pixel-by pixel correction of the autoradiographic images. For detection of inclusions of precious metals, a method for analysis of the acquired dose dynamics during sample decay has been developed. The method is based on the software processing pixel by pixel a time-series of coaxial autoradiographic images and generation of the secondary meta-images allowing interpretation regarding the presence of interesting inclusions based on half-lives. The method is tested for analysis of copper-nickel polymetallic ores. The developed solutions considerably expand the possible applications of digital gamma-activation autoradiography. (orig.)

  3. Development of digital gamma-activation autoradiography for analysis of samples of large area

    Energy Technology Data Exchange (ETDEWEB)

    Kolotov, V.P.; Grozdov, D.S.; Dogadkin, N.N.; Korobkov, V.I. [Russian Academy of Sciences, Moscow (Russian Federation). Vernadsky Inst. of Geochemistry and Analytical Chemistry

    2011-07-01

    Gamma-activation autoradiography is a prospective method for screening detection of inclusions of precious metals in geochemical samples. Its characteristics allow analysis of thin sections of large size (tens of cm2), that favourably distinguishes it among the other methods for local analysis. At the same time, the activating field of the accelerator bremsstrahlung, displays a sharp intensity decrease relative to the distance along the axis. A method for activation dose ''equalization'' during irradiation of the large size thin sections has been developed. The method is based on the usage of a hardware-software system. This includes a device for moving the sample during the irradiation, a program for computer modelling of the acquired activating dose for the chosen kinematics of the sample movement and a program for pixel-by pixel correction of the autoradiographic images. For detection of inclusions of precious metals, a method for analysis of the acquired dose dynamics during sample decay has been developed. The method is based on the software processing pixel by pixel a time-series of coaxial autoradiographic images and generation of the secondary meta-images allowing interpretation regarding the presence of interesting inclusions based on half-lives. The method is tested for analysis of copper-nickel polymetallic ores. The developed solutions considerably expand the possible applications of digital gamma-activation autoradiography. (orig.)

  4. Bulk handling benefits from ICT

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-15

    The efficiency and accuracy of bulk handling is being improved by the range of management information systems and services available today. As part of the program to extend Richards Bay Coal Terminal, Siemens is installing a manufacturing execution system which coordinates and monitors all movements of raw materials. The article also reports recent developments by AXSMarine, SunGuard Energy, Fuelworx and Railworx in providing integrated tools for tracking, managing and optimising solid/liquid fuels and rail car maintenance activities. QMASTOR Ltd. has secured a contract with Anglo Coal Australia to provide its Pit to Port.net{reg_sign} and iFuse{reg_sign} software systems across all their Australians sites, to include pit-to-product stockpile management. 2 figs.

  5. Recoil Reactions in Neutron-Activation Analysis. The Szilard-Chalmers Effect Applied in the Analysis of Biological Samples; II. Transfer of Activities from Container Material to Sample

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D

    1965-01-15

    The present investigation consists of two parts. The one part concerns the application of the Szilard-Chalmers effect in the separation of activities from neutron-irradiated biological material. The nuclides As-76, Au-198, Br-82, Ca-47, Cd-115, Cl-38, Co-60, Cr-51, Cs-134, Cu-64, Fe-59, Mg-27, Mo-99, Na-24, P-32, Rb-86, Se-75 and Zn-65 were extracted from either liver tissue, whole blood or muscle tissue. The extractions were made in water, 0.1 N HCl, 1 N HCl or conc. HCl respectively. The nuclides belonging to the alkali metals together with Br and Cl, were found present in the water and hydrochloric extracts to 96 per cent or more. In the conc. HCl extracts, the greater part of the nuclides were recovered to 90 per cent or more. The enrichment of the different nuclides obtained in the Szilard-Chalmers process was investigated as follows. After extraction of the nuclides from the irradiated material the solution obtained was divided into two parts, one of which was reactivated. The specific activities of the nuclides in the two solutions were then compared, thus giving the enrichment factor In one case, the residue of organic material after extraction was reactivated and the activity compared to the initial one. The effect of dilution together with the application of short irradiation periods favouring higher yield was investigated in the separation of Fe-59 from whole blood samples irradiated in frozen conditions. The other part of the investigation concerns an estimation of the amounts of the activities originating from polyethylene and quartz containers transferred to container surface due to the recoil effect in the thermal neutron-capture process, thus causing contamination of the sample. The universal range-energy relationship given by Lindhard and Scharff has been applied in these calculations. As regards containers with impurities in the ppm region, the amounts of activities transferred owing to this effect were found to be quite negligible. However, when

  6. Identification of uranium signatures in swipe samples on verification of nuclear activities for nuclear safeguards purposes

    International Nuclear Information System (INIS)

    Pestana, Rafael Cardoso Baptistini

    2013-01-01

    The use of environmental sampling for safeguards purposes, has been applied by the International Atomic Energy Agency–IAEA since 1996 and are routinely used as a complementary measure to strengthen the traditional nuclear safeguards procedures. The aim is verify if the states signatory to the safeguards agreements are not diverging their peaceful nuclear activities for undeclared nuclear activities. This work describes a new protocol of collect and analysis of the swipe samples for identification of nuclear signatures that may be related to the nuclear activities developed in the inspected facility. This work was used as a case of study a real uranium conversion plant of the nuclear fuel cycle of IPEN. The strategy proposed uses different analytical techniques, such as alpha radiation meter, SEM-EDX and ICP-MS to identify signatures of uranium adhered to the swipe samples. In the swipe samples analysis, it was possible to identify particles of UO 2 F 2 and UF4 through the morphological comparison and semi-quantitative analyses performed by SEM-EDX technique. In this work, methods were used that as a result has the average isotopic composition of the sample, in which the enrichment ranged from 1.453 ± 0.023 to 18.24 % ± 0.15 % in the 235 U isotope. Through these externally collections, a non-intrusive sampling, it was possible to identify enriched material handling activities with enrichment of 1.453 % ± 0.023 % to 6.331 ± 0.055 % in the isotope 235 U, as well as the use of reprocessed material, through the identification of the 236 U isotope. The uncertainties obtained for the n( 235 U)/n( 238 U) ratio varied from 0.40% to 0.86 % for the internal swipe samples. (author)

  7. Quality of life and physical activity in a sample of Brazilian older adults.

    Science.gov (United States)

    Guedes, Dartagnan P; Hatmann, Angélica C; Martini, Fábio Antônio N; Borges, Marcelo B; Bernardelli, Rinaldo

    2012-03-01

    To investigate the association between physical activity and quality of life in a sample of Brazilian older adults. The Portuguese version of the World Health Organization Quality of Life Instrument-Older Adults Module and International Physical Activity Questionnaire was administered to 1,204 subjects (645 women and 559 men) aged ≥ 60 years. Older adults of both genders who reported to be more physically active attributed higher scores to the sensory ability, autonomy, and intimacy domains, in addition to presenting significantly higher overall quality of life, irrespectively of age, marital status, educational level, and socioeconomic status. Specifically in women, the scores obtained for the social participation domain were significantly higher in the strata of active and very active subjects when compared to sedentary subjects. The results indicate that increases in the levels of physical activity can contribute to improvements in quality of life of older adults.

  8. Guidance for establishment and implementation of a national sample management program in support of EM environmental sampling and analysis activities

    International Nuclear Information System (INIS)

    1994-01-01

    The role of the National Sample Management Program (NSMP) proposed by the Department of Energy's Office of Environmental Management (EM) is to be a resource for EM programs and for local Field Sample Management Programs (FSMPs). It will be a source of information on sample analysis and data collection within the DOE complex. Therefore the NSMP's primary role is to coordinate and function as a central repository for information collected from the FSMPs. An additional role of the NSMP is to monitor trends in data collected from the FSMPs over time and across sites and laboratories. Tracking these trends will allow identification of potential problems in the sampling and analysis process

  9. Estimated neutron-activation data for TFTR. Part II. Biological dose rate from sample-materials activation

    International Nuclear Information System (INIS)

    Ku, L.; Kolibal, J.G.

    1982-06-01

    The neutron induced material activation dose rate data are summarized for the TFTR operation. This report marks the completion of the second phase of the systematic study of the activation problem on the TFTR. The estimations of the neutron induced activation dose rates were made for spherical and slab objects, based on a point kernel method, for a wide range of materials. The dose rates as a function of cooling time for standard samples are presented for a number of typical neutron spectrum expected during TFTR DD and DT operations. The factors which account for the variations of the pulsing history, the characteristic size of the object and the distance of observation relative to the standard samples are also presented

  10. Big bang nucleosynthesis constraints on bulk neutrinos

    International Nuclear Information System (INIS)

    Goh, H.S.; Mohapatra, R.N.

    2002-01-01

    We examine the constraints imposed by the requirement of successful nucleosynthesis on models with one large extra hidden space dimension and a single bulk neutrino residing in this dimension. We solve the Boltzmann kinetic equation for the thermal distribution of the Kaluza-Klein modes and evaluate their contribution to the energy density at the big bang nucleosynthesis epoch to constrain the size of the extra dimension R -1 ≡μ and the parameter sin 2 2θ which characterizes the mixing between the active and bulk neutrinos

  11. Occurrence of Giardia cysts and Cryptosporidium oocysts in activated sludge samples in Campinas, SP, Brazil.

    Science.gov (United States)

    Santos, Luciana Urbano; Bonatti, Taís Rondello; Cantusio Neto, Romeu; Franco, Regina Maura Bueno

    2004-01-01

    Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i) concentration by the ether clarification procedure (ECP) and to ii) purification by sucrose flotation method (SFM) and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8) when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7). As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively). Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2) were detected positive by using ECP, while for SFM, only one sample (examined by kit 1) was positive (12.5%). The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.

  12. Determination of minor-and trace elements in magnesite samples, by activation analysis

    International Nuclear Information System (INIS)

    Sepulveda Munita, C.J.A.

    1979-01-01

    A method employing activation analysis with thermal neutron was developed for the determination of minor and trace elements in magnesite samples from the states of Ceara and Bahia (Brazil). Ten samples were analyzed. A qualitative analysis of the samples indicated the presence of Mn, Fe, Sc, Ca, Cu, Co and some of the lanthanides. The experimental part includes a non-destructive analysis of manganese and analysis with chemical separation of the other elements, individually or in groups, after sample dissolution, The dissolutions were made with concentrated HCl and the further separations were carried out in 8 N HCl medium. Iron was separated by means of an extraction of HFeCl 4 with isopropyl ether. Scandium and calcium were determined by retention of scandium with di-(2-ehylhexyl) phosphoric acid (HDEHP). The activities of 46 Sc and 47 Sc (a 47 Ca descendant) were employed for the analysis of scandium and calcium in the sample. In the effluent of the kieselguhr column copper and cobalt were determined, after retention in an anionic resin of the CuCl - 3 and CoCl - 3 complexes. Finally, in the effluent of the resin, the lanthanide group was separated by oxalate precipitation. In the gamma-ray spectrum of this precipitate the elements europium, cerium, samarium and lanthanum were determined. A detailed study of the possible interferences in the neutron activation analysis of the elements analysed was also made. The precision and accuracy of the results obtained and the sensitivity of the method are discussed. (Author) [pt

  13. Comparison of chlorzoxazone one-sample methods to estimate CYP2E1 activity in humans

    DEFF Research Database (Denmark)

    Kramer, Iza; Dalhoff, Kim; Clemmesen, Jens O

    2003-01-01

    OBJECTIVE: Comparison of a one-sample with a multi-sample method (the metabolic fractional clearance) to estimate CYP2E1 activity in humans. METHODS: Healthy, male Caucasians ( n=19) were included. The multi-sample fractional clearance (Cl(fe)) of chlorzoxazone was compared with one...... estimates, Cl(est) at 3 h or 6 h, and MR at 3 h, can serve as reliable markers of CYP2E1 activity. The one-sample clearance method is an accurate, renal function-independent measure of the intrinsic activity; it is simple to use and easily applicable to humans.......-time-point clearance estimation (Cl(est)) at 3, 4, 5 and 6 h. Furthermore, the metabolite/drug ratios (MRs) estimated from one-time-point samples at 1, 2, 3, 4, 5 and 6 h were compared with Cl(fe). RESULTS: The concordance between Cl(est) and Cl(fe) was highest at 6 h. The minimal mean prediction error (MPE) of Cl...

  14. Microfabricated Bulk Piezoelectric Transformers

    Science.gov (United States)

    Barham, Oliver M.

    Piezoelectric voltage transformers (PTs) can be used to transform an input voltage into a different, required output voltage needed in electronic and electro- mechanical systems, among other varied uses. On the macro scale, they have been commercialized in electronics powering consumer laptop liquid crystal displays, and compete with an older, more prevalent technology, inductive electromagnetic volt- age transformers (EMTs). The present work investigates PTs on smaller size scales that are currently in the academic research sphere, with an eye towards applications including micro-robotics and other small-scale electronic and electromechanical sys- tems. PTs and EMTs are compared on the basis of power and energy density, with PTs trending towards higher values of power and energy density, comparatively, indicating their suitability for small-scale systems. Among PT topologies, bulk disc-type PTs, operating in their fundamental radial extension mode, and free-free beam PTs, operating in their fundamental length extensional mode, are good can- didates for microfabrication and are considered here. Analytical modeling based on the Extended Hamilton Method is used to predict device performance and integrate mechanical tethering as a boundary condition. This model differs from previous PT models in that the electric enthalpy is used to derive constituent equations of motion with Hamilton's Method, and therefore this approach is also more generally applica- ble to other piezoelectric systems outside of the present work. Prototype devices are microfabricated using a two mask process consisting of traditional photolithography combined with micropowder blasting, and are tested with various output electri- cal loads. 4mm diameter tethered disc PTs on the order of .002cm. 3 , two orders smaller than the bulk PT literature, had the followingperformance: a prototype with electrode area ratio (input area / output area) = 1 had peak gain of 2.3 (+/- 0.1), efficiency of 33 (+/- 0

  15. Determination of chromium, cobalt and nickel in tissue samples by radiochemical activation analysis

    International Nuclear Information System (INIS)

    Reisell, A.; Lakomaa, E.L.

    1983-03-01

    A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel in tissue samples. A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel has been developed. The destruction device used consisted of a combined wet-ashing-distillation and ion-exchange system. Six samples could be treated at the same time. The samples were wet-ashed with H*L2SO*L4-H*L2O*L2 mixture. Volatile elements were distilled as bromide compounds with HBr*H-. The distillation residue in 8M HCl was passed through hydrated antimony pentoxide (HAP) in order to remove disturbing *H2*H4Na-activity and through a Dowex 2 x 8 column so as to retain *H6*H0Co (formed from *H5*H8Ni). Chromium was elutriated from the column and precipitated as Cr(OH)*L3 for the removal of disturbing *H3*H2P-activity. The standards and samples were treated in a similar manner each so that the yield determination is not necessarily needed. The yields by tracer experiments were (43 +- 5) % for Cr, (93 +- 4) % for Co and (88 +- 14) % for Ni. The precision and accuracy of the method were studied by using reference materials of the National Bureau of Standards (NBS) and the International Atomic Energy Agency (IAEA)

  16. Re-estimating sample size in cluster randomized trials with active recruitment within clusters

    NARCIS (Netherlands)

    van Schie, Sander; Moerbeek, Mirjam

    2014-01-01

    Often only a limited number of clusters can be obtained in cluster randomised trials, although many potential participants can be recruited within each cluster. Thus, active recruitment is feasible within the clusters. To obtain an efficient sample size in a cluster randomised trial, the cluster

  17. Neutron activation analysis in geological samples containing rare earths, uranium and thorium

    International Nuclear Information System (INIS)

    Vasconcellos, M.B.A.; Figueiredo, A.M.G.; Berretta, J.R.; Soares, J.C.A.C.R.; Fratin, L.; Goncales, O.L.; Botelho, S.

    1990-01-01

    The neutron activation analysis method was used for determination of rare earths, uranium, thorium and other tracks in geological samples, under the geological standard JB-1 (Geological Survey of Japan) and S-8 and S-13 (IAEA). (L.C.J.A.)

  18. Distribution of {sup 90}Sr activities in the environmental radiation samples of Jeju Island, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Han, Chung Hun; Park, Youn Hyun; Lee, Young Gyu; Park, Jae Woo [Jeju National University, Jeju (Korea, Republic of)

    2016-12-15

    This work was to get information about {sup 90}Sr contamination of the environment by using soil and moss from selected areas in Jeju Island, Korea. The activities of {sup 90}Sr in soil and moss samples were investigated at nine locations of Jeju island, Korea. The soil samples have been collected at 4 sites of Jeju island during June to August of 2013, analyzed for vertical distribution of {sup 90}Sr activities. The moss samples have been collected at 5 sites of Jeju island during November of 2011 to June of 2012, and analyzed for radioactive {sup 90}Sr. The {sup 90}Sr vertical concentrations in the investigated soil samples were 2.77 to 18.24 Bq·kg{sup -1} in eastern part, 1.69 to 18.27 Bq·kg{sup -1} in northern part, 3.76 to 13.46 Bq·kg{sup -1} in the western part and 1.09 to 8.70 Bq·kg{sup -1} in the southern part of the Mt. Halla in Jeju island, respectively. Activities of {sup 90}Sr show the highest value at the surface soil and decrease with depth. The activity concentration measured was in the range of 79.6 to 363 Bq·kg{sup -1} -dry moss. This material is expected to be basis reference for survey of environmental radioactivity in Jeju Island.

  19. Determination of traces of lithium in biological, environmental and metal samples by neutron activation analysis

    International Nuclear Information System (INIS)

    Yang, J.Y.; Tseng, C.L.; Lo, J.M.; Yang, M.H.

    1985-01-01

    Lithium in environmental, biological and metal samples was determined by neutron activation analysis via the 6 Li(n,α)T and 16 O(T,n) 18 F reactions. The samples were converted to aqueous solutions either by dissolution or by digestion and their aliquots were irradiated in a nuclear reactor for 2 h. The irradiated sample solution, was placed in a ZrO 2 column on which the 18 F nuclide was adsorbed. Most of the coexisting nuclides 24 Na, 82 Br, 38 Cl, 64 Cu, etc. were separated by elution with pH 1proportional3 solution. The column was subjected to a Ge(Li) detector for γ-ray spectrometry. The lithium content in the sample was estimated from the 18 F activity obtained. The matrix effect can be eliminated by either strong dilution of the samples in aqueous medium or by the method of standard addition. Lithium can be determined with high precision and accuracy in sub-ppm samples. (orig.) [de

  20. Trace elements detection in whole food samples by Neutron Activation Analysis, k0-method

    International Nuclear Information System (INIS)

    Sathler, Márcia Maia; Menezes, Maria Ângela de Barros Correia; Salles, Paula Maria Borges de

    2017-01-01

    Inorganic elements, from natural and anthropogenic sources are present in foods in different concentrations. With the increase in anthropogenic activities, there was also a considerable increase in the emission of these elements in the environment, leading to the need of monitoring the elemental composition of foods available for consumption. Numerous techniques have been used to detect inorganic elements in biological and environmental matrices, always aiming at reaching lower detection limits in order to evaluate the trace element content in the sample. Neutron activation analysis (INAA), applying the k 0 -method, produces accurate and precise results without the need of chemical preparation of the samples – that could cause their contamination. This study evaluated the presence of inorganic elements in whole foods samples, mainly elements on trace levels. For this purpose, seven samples of different types of whole foods were irradiated in the TRIGA MARK I IPR-R1 research reactor - located at CDTN/CNEN, in Belo Horizonte, MG. It was possible to detect twenty two elements above the limit of detection in, at least, one of the samples analyzed. This study reaffirms the INAA, k 0 - method, as a safe and efficient technique for detecting trace elements in food samples. (author)

  1. Evaluation of active sampling strategies for the determination of 1,3-butadiene in air

    Science.gov (United States)

    Vallecillos, Laura; Maceira, Alba; Marcé, Rosa Maria; Borrull, Francesc

    2018-03-01

    Two analytical methods for determining levels of 1,3-butadiene in urban and industrial atmospheres were evaluated in this study. Both methods are extensively used for determining the concentration of volatile organic compounds in the atmosphere and involve collecting samples by active adsorptive enrichment on solid sorbents. The first method uses activated charcoal as the sorbent and involves liquid desorption with carbon disulfide. The second involves the use of a multi-sorbent bed with two graphitised carbons and a carbon molecular sieve as the sorbent, with thermal desorption. Special attention was paid to the optimization of the sampling procedure through the study of sample volume, the stability of 1,3-butadiene once inside the sampling tube and the humidity effect. In the end, the thermal desorption method showed better repeatability and limits of detection and quantification for 1,3-butadiene than the liquid desorption method, which makes the thermal desorption method more suitable for analysing air samples from both industrial and urban atmospheres. However, sampling must be performed with a pre-tube filled with a drying agent to prevent the loss of the adsorption capacity of the solid adsorbent caused by water vapour. The thermal desorption method has successfully been applied to determine of 1,3-butadiene inside a 1,3-butadiene production plant and at three locations in the vicinity of the same plant.

  2. Trace elements detection in whole food samples by Neutron Activation Analysis, k{sub 0}-method

    Energy Technology Data Exchange (ETDEWEB)

    Sathler, Márcia Maia; Menezes, Maria Ângela de Barros Correia, E-mail: maia.sathler@gmail.com, E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Salles, Paula Maria Borges de, E-mail: pauladesalles@yahoo.com.br [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    Inorganic elements, from natural and anthropogenic sources are present in foods in different concentrations. With the increase in anthropogenic activities, there was also a considerable increase in the emission of these elements in the environment, leading to the need of monitoring the elemental composition of foods available for consumption. Numerous techniques have been used to detect inorganic elements in biological and environmental matrices, always aiming at reaching lower detection limits in order to evaluate the trace element content in the sample. Neutron activation analysis (INAA), applying the k{sub 0}-method, produces accurate and precise results without the need of chemical preparation of the samples – that could cause their contamination. This study evaluated the presence of inorganic elements in whole foods samples, mainly elements on trace levels. For this purpose, seven samples of different types of whole foods were irradiated in the TRIGA MARK I IPR-R1 research reactor - located at CDTN/CNEN, in Belo Horizonte, MG. It was possible to detect twenty two elements above the limit of detection in, at least, one of the samples analyzed. This study reaffirms the INAA, k{sub 0} - method, as a safe and efficient technique for detecting trace elements in food samples. (author)

  3. Development of activated charcoal impregnated air sampling filter media : their characteristics and use

    International Nuclear Information System (INIS)

    Khan, A.A.; Ramarathinam, K.; Gupta, S.K.; Deshingkar, D.S.; Kishore, A.G.

    1975-01-01

    Because of its low maximum permissible concentration in air, air-borne radioiodine must be accurately monitored in contaminated air streams, in the working environment and handling facilities, before release to the environment from the nuclear facilities. Activated charcoal impregnated air sampling filter media are found to be most suitable for monitoring airborne iodine-131. Because of its simplicity and reproducible nature in assessment of air-borne radioactive iodine, the work on the development of such media was undertaken in order to find a suitable substitute for imported activated charcoal impregnated air sampling filter media. Eight different media of such type were developed, evaluated and compared with two imported media. Best suitable medium is recommended for its use in air-borne iodine sampling which was found to be even better suited than imported media of such type. (author)

  4. Developing bulk exchange spring magnets

    Science.gov (United States)

    Mccall, Scott K.; Kuntz, Joshua D.

    2017-06-27

    A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

  5. Comparison of active and passive sampling strategies for the monitoring of pesticide contamination in streams

    Science.gov (United States)

    Assoumani, Azziz; Margoum, Christelle; Guillemain, Céline; Coquery, Marina

    2014-05-01

    constants (Rs). Each constant links the mass of the a target contaminant accumulated in the sampler to its concentration in water. At the end of the field application, the Rs are used to calculate the TWA concentration of each target contaminant with the final mass of the contaminants accumulated in the sampler. Stir Bar Sorptive Extraction (SBSE) is a solvent free sample preparation technique dedicated to the analysis of moderately hydrophobic to hydrophobic compounds in liquid and gas samples. It is composed of a magnet enclosed in a glass tube coated with a thick film of polydimethysiloxane (PDMS). We recently developed the in situ application of SBSE as a passive sampling technique (herein named "Passive SBSE") for the monitoring of agricultural pesticides. The aim of this study is to perform the calibration of the passive SBSE in the laboratory, and to apply and compare this technique to active sampling strategies for the monitoring of 16 relatively hydrophobic to hydrophobic pesticides in streams, during 2 1-month sampling campaigns. Time-weighted averaged concentrations of the target pesticides obtained from passive SBSE were compared to the target pesticide concentrations of grab samples, and time-related and flow-dependent samples of the streams. Results showed passive SBSE as an efficient alternative to conventional active sampling strategies.

  6. Impact of Cesium decontamination on performances of high activity sample analysis

    Energy Technology Data Exchange (ETDEWEB)

    Maillard, Christophe; Boyer-Deslys, Valerie; Dautheribes, Jean L.; Esbelin, Eric; Beres, Andre; Jan, Steve; Baghdadi, Sarah; Rivier, Cedric [CEA, Nuclear Energy Division, Bagnols sur Ceze (France). RadioChemistry and Processes Dept.

    2017-09-01

    Experiments in the ATALANTE facility can lead to high activity samples (for example the dissolution of hulls and spent fuels), essentially coming from the presence of {sup 137}Cs. Usually, these samples are handled in a shielded cell. The removal of this radionuclide from the sample would make it possible to handle it in glove boxes without having to perform an important dilution in the shielded cells beforehand. It would allow to analyze samples using techniques usually implemented in glove boxes (such as ICP, α spectrometry..) and to reach lower detection and quantification limits. To do so, a separation by extraction chromatography using a Triskem AMP-PAN column was developed. A cesium decontamination factor higher than 5 x 10{sup 4} and detection limits improvement up to a factor 100 were obtained.

  7. On multielement analysis of biological samples with the aid of neutron activation

    International Nuclear Information System (INIS)

    Iyengar, G.V.

    1980-01-01

    A main objective of this study was elucidation of problems of sampling and sample preparation methods for multielement analysis of environmental and biological specimens. Another was assessment of the potentials of multielement neutron activation analysis (NAA) in environmental and biological research. In an attempt to explain the great differences in the elemental concentration ranges between biopsy and autopsy samples as reported in the literature, it was shown that post mortem changes induce great variations in the apparent elemental composition of autopsy specimens resulting in serious systematic errors. Applications of NAA to analysis of tissues of experimental animals, human tissues in health and disease, and environmental samples are illustrated with several examples. The suitability of NAA for routine analysis of elements such as Cr, Mo and Se, which are difficult to determine by other methods has been specially discussed. (author)

  8. Determination of short-lived trace elements in environmental samples by neutron activation analysis

    International Nuclear Information System (INIS)

    Wardani, S.; Sihombing, E.; Hamzah, A.; Rochidi; Hery, P.S.; Hartaman, S.; Iman, J.

    1998-01-01

    Concentration of a short-lived trace elements in environmental samples were determined by neutron activation analysis, a counting loss often occur due to the high counting rate. A Pile-Up Rejecter (PUR) electric circuit was installed in counting a short-lived trace elements by a γ-ray spectrometer in order to correct a counting loss. The samples were irradiated for 30∼60 seconds at neutron flux of 3.5 x 10 12 n.cm -2 .s -1 , then the samples cooled for 120 second and counted for 180 second using this system. The nuclides concentration in the varieties environmental samples have a difference analysis result, was more accurate and precise, which the measured result would be 30 % more higher by PUR system than the result would be counted using a conventional γ-ray spectrometry method

  9. A semi-empirical approach to calculate gamma activities in environmental samples

    International Nuclear Information System (INIS)

    Palacios, D.; Barros, H.; Alfonso, J.; Perez, K.; Trujillo, M.; Losada, M.

    2006-01-01

    We propose a semi-empirical method to calculate radionuclide concentrations in environmental samples without the use of reference material and avoiding the typical complexity of Monte-Carlo codes. The calculation of total efficiencies was carried out from a relative efficiency curve (obtained from the gamma spectra data), and the geometric (simulated by Monte-Carlo), absorption, sample and intrinsic efficiencies at energies between 130 and 3000 keV. The absorption and sample efficiencies were determined from the mass absorption coefficients, obtained by the web program XCOM. Deviations between computed results and measured efficiencies for the RGTh-1 reference material are mostly within 10%. Radionuclide activities in marine sediment samples calculated by the proposed method and by the experimental relative method were in satisfactory agreement. The developed method can be used for routine environmental monitoring when efficiency uncertainties of 10% can be sufficient.(Author)

  10. System for sampling active solutions in transport container; Systeme de prelevements de solutions actives sur les recipients de transport

    Energy Technology Data Exchange (ETDEWEB)

    Fradin, J.

    1958-12-03

    This report presents a system aimed at sampling active solution from a specific transport container (SCRGR model) while transferring this solution with a maximum safety. The sampling principle is described (a flexible tube connected to the receiving container, with a needle at the other end which goes through a rubber membrane and enters a plunger tube). Its benefits are outlined (operator protection, reduction of contamination risk; only the rubber membrane is removed and replaced). Some manufacturing details are described concerning the membrane and the cover.

  11. Large sample neutron activation analysis: establishment at CDTN/CNEN, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, Maria Angela de B.C., E-mail: menezes@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Jacimovic, Radojko, E-mail: radojko.jacimovic@ijs.s [Jozef Stefan Institute, Ljubljana (Slovenia). Dept. of Environmental Sciences. Group for Radiochemistry and Radioecology

    2011-07-01

    In order to improve the application of the neutron activation technique at CDTN/CNEN, the large sample instrumental neutron activation analysis is being established, IAEA BRA 14798 and FAPEMIG APQ-01259-09 projects. This procedure, LS-INAA, usually requires special facilities for the activation as well as for the detection. However, the TRIGA Mark I IPR R1, CDTN/CNEN has not been adapted for the irradiation and the usual gamma spectrometry has being carried out. To start the establishment of the LS-INAA, a 5g sample - IAEA/Soil 7 reference material was analyzed by k{sub 0}-standardized method. This paper is about the detector efficiency over the volume source using KayWin v2.23 and ANGLE V3.0 software. (author)

  12. Carnivore activity in the Sima de los Huesos (Atapuerca, Spain) hominin sample

    Science.gov (United States)

    Sala, Nohemi; Arsuaga, Juan Luis; Martínez, Ignacio; Gracia-Téllez, Ana

    2014-08-01

    The Sima de los Huesos (SH) site is the largest accumulation of human remains from the Middle Pleistocene known to date. Studies in the last two decades have proposed different hypotheses to explain carnivore activity in the SH human sample. This study provides new data in order to test these different interpretations, and therefore to understand the role of the carnivores in site formation at SH. Carnivores are usually not the origin of large accumulations of hominin fossils in the Eurasian record. The results show that marks of carnivore activity in the SH sample appear very infrequently, which we interpret as indicating that carnivore activity was very sporadic at the site. This is in stark contrast with previous studies. The comparison of bone modification patterns at SH to actualistic carnivore data allows us to suggest that bears were likely to have been the carnivore responsible for the modification observed on both human and bear fossils.

  13. Determination of gross gamma and gross beta activities in liquid effluent samples. Phase I

    International Nuclear Information System (INIS)

    Curtis, K.E.; Sood, S.P.

    1985-08-01

    Several inadequacies in the presently used procedures for gross gamma and gross beta measurements in aqueous wastes have been identified. Both the presence of suspended particulate activity and the use of cesium-137 as a calibration standard can cause gross gamma measurements to overestimate the actual activity in the sample. At the same time, sample preparation for the determination of gross beta activities causes large losses of radioiodine before the measurement step and the presence of solid material can cause a serious decrease in the beta counting efficiency. A combination of these errors could result in large discrepancies between the results obtained by the two measurement methods. Improved procedures are required to overcome these problems

  14. Epiboron instrumental neutron activation analysis for the determination of iodine in various salt samples

    International Nuclear Information System (INIS)

    Nyarko, B.J.B.; Serfor-Armah, Y.; Osae, S.; Akaho, E.H.K.; Anim-Sampong, S.; Maakuu, B.T.

    2001-01-01

    Epiboron instrumental neutron activation analysis (EINAA) using flexible boron as thermal neutron filter, has been used to analyze several salt samples obtained from various markets in Ghana for iodine. The method involves the irradiation of samples in boron carbide-lined polyethylene vials at the outer irradiation site of the Ghana Research Reactor-1 (GHARR-1). The samples were then counted directly without any pre-treatment on a Canberra N-type HPGe detector. The qualitative and quantitative analyses were done using the 443 keV photopeak of 128 I. The precision and accuracy of the method have been evaluated and the detection limits of the various samples were calculated. The values of iodine determined in the iodized salt range between 10.0 and 210 ppm. For non-iodinated salts, iodine levels were below 500 ppb. The values obtained show great variations among the salt samples, sample collection time and from market to market. This results show that the method can be successfully applied in the determination of trace amount of iodine in salt samples without any chemical separation. (author)

  15. Analysis of toxical element in the whitening cream cosmetic samples using neutron activation analysis (NAA)

    International Nuclear Information System (INIS)

    Th Rina M; Sunarko

    2007-01-01

    Neutron activation analysis has been done to analyze of toxical elements that is not allowed in the whitening cream cosmetic. These samples have been randomly selected from the cosmetic market. The samples were irradiated at thermal neutron flux of 10"1"33n.cm"-"2s"-"1 in the irradiation facility of rabbit system in the RSG-GAS reactor Serpong. Counting of irradiated samples have been done by a high resolution HPGe detector couple to multichannel analyzer. Data have been analyzed by GENIE 2000. The sample have been qualitatively determined up to 19 elements. These elements are: As, Br, Ce, Co, Cr, Cs, Eu, Fe, Hg, K, La, Na, Rb, Sb, Se, Sc, Rb, Th, IV, and Zn. The result of qualitative analysis showed that the toxical elements present in the samples are Hg, As, Cr and Sb with the following concentration ranges in μg/g 25.2-65.1, 1.0-6.3, 30.5-89.1 and 2.9-5.3, respectively and these element not allowed in the whitening cream cosmetic. Besides that, the others elements have been detected in the samples are Br, Fe, Zn, Sc and Co, with concentration ranges, 13.1-36.4, 65.6-159.3, 0.79-77.1, 0.5-19.5, and 6.8-31.7 μg/g, respectively, in the sample whitening cream cosmetic. (author)

  16. Optimalization activity of ZnO NR/TiO2 NR-P3HT as an active layer based on hybrid bulk heterojunction on dye sensitized solar cell (DSSC)

    International Nuclear Information System (INIS)

    Saputri, Liya Nikmatul Maula Zulfa; Ramelan, Ari Handono; Hanif, Qonita Awliya; Hasanah, Yesi Ihdina Fityatal; Prajanira, Lau Bekti; Wahyuningsih, Sayekti

    2016-01-01

    Dye sensitized solar cell (DSSC) with metal inorganic and conjugated organic polymer mixture, ZnO NR/TiO 2 NR-P3HT as an active layer based on hybrid bulk heterojunction has been studied. The hybrid material was used to optimize DSSC performs for better efficiency than only TiO 2 as an electrode. Synthesis of TiO 2 nanorods (NR) was conducted by ball milling 1000 rpm for 4 hours and strong base reaction by hydrothermal process at 120 °C overnight. And the ZnO NR was synthesized from Zn(NO 3 ) 2 .4H 2 O precusor by hydrotermal process at 90 °C for 5 hours and calcined on various temperature s of 400, 600, and 800 °C. ZnO NR was coated into an Tndium Tin Oxide (TTO) glass to collecting electron s effectively, where TiO 2 NR were incorporated with poly(3 -hexylthiophene) (P3HT) on various concentration s of 5, 10, 15 mg/mL to obtain a larger surface area. Material characterization were performed by X -Ray Diffraction (XRD) and Uv-Vis spectrophotometer. For an application of DSSC were measured by T-V Keithley Multimeter and the efficiency of DSSC at various P3HT’s concentrations of 5, 10, 15 mg/mL were 7.44 × 10 −3 , 0.0114, 0.0104, respectively. The maximum efficiency of DSSC was showed when TiO 2 NR-P3HT’s concentration was 10 mg/mL.

  17. Optimalization activity of ZnO NR/TiO2 NR-P3HT as an active layer based on hybrid bulk heterojunction on dye sensitized solar cell (DSSC)

    Energy Technology Data Exchange (ETDEWEB)

    Saputri, Liya Nikmatul Maula Zulfa; Ramelan, Ari Handono; Hanif, Qonita Awliya; Hasanah, Yesi Ihdina Fityatal; Prajanira, Lau Bekti; Wahyuningsih, Sayekti, E-mail: sayektiw@mipa.uns.ac.id [Chemistry Department, Faculty of Mathematics and Natural Sciences, Sebelas Maret University, Ir.Sutami 36A Kentingan Surakarta 57/26, Central Java (Indonesia)

    2016-04-19

    Dye sensitized solar cell (DSSC) with metal inorganic and conjugated organic polymer mixture, ZnO NR/TiO{sub 2} NR-P3HT as an active layer based on hybrid bulk heterojunction has been studied. The hybrid material was used to optimize DSSC performs for better efficiency than only TiO{sub 2} as an electrode. Synthesis of TiO{sub 2} nanorods (NR) was conducted by ball milling 1000 rpm for 4 hours and strong base reaction by hydrothermal process at 120 °C overnight. And the ZnO NR was synthesized from Zn(NO{sub 3}){sub 2}.4H{sub 2}O precusor by hydrotermal process at 90 °C for 5 hours and calcined on various temperature s of 400, 600, and 800 °C. ZnO NR was coated into an Tndium Tin Oxide (TTO) glass to collecting electron s effectively, where TiO{sup 2} NR were incorporated with poly(3 -hexylthiophene) (P3HT) on various concentration s of 5, 10, 15 mg/mL to obtain a larger surface area. Material characterization were performed by X -Ray Diffraction (XRD) and Uv-Vis spectrophotometer. For an application of DSSC were measured by T-V Keithley Multimeter and the efficiency of DSSC at various P3HT’s concentrations of 5, 10, 15 mg/mL were 7.44 × 10{sup −3}, 0.0114, 0.0104, respectively. The maximum efficiency of DSSC was showed when TiO{sup 2} NR-P3HT’s concentration was 10 mg/mL.

  18. Determination of trace elements in fisheries samples by instrumental neutron and photon activation analysis

    International Nuclear Information System (INIS)

    Chattopadhyay, A.; Ellis, K.M.; Nimalasiri Desilva, K.

    1979-01-01

    An instrumental neutron activation analysis (INAA) method has been developed for the simultaneous determination of trace concentrations of up to 23 elements in fisheries samples. The INAA method consists of irradiations of wet and lyophilized cod muscle and liver samples for three different periods at a flux density of 5x10 11 n.cm -2 .s -1 and subsequent measurements after four different decay periods using high-resolution Ge(Li) gamma-ray spectrometry. Concentrations of several essential and toxic elements have been determined. Loss of certain elements during lyophilization has been studied. Elemental distribution in muscles and livers as a function of the age of fish has been investigated. Precision and accuracy of the INAA method have been evaluated by analysing replicate samples, National Bureau of Standards' bovine liver standard reference material, and an intercalibration fish flour sample provided by the International Council for the Exploration of the Sea. A few fish samples have also been analysed by an alternative method, namely instrumental photon activation analysis (IPAA). Elemental concentrations determined by both INAA and IPAA methods are reported here. (author)

  19. ROTATION AND MAGNETIC ACTIVITY IN A SAMPLE OF M-DWARFS

    International Nuclear Information System (INIS)

    Browning, Matthew K.; Basri, Gibor; Marcy, Geoffrey W.; Zhang Jiahao; West, Andrew A.

    2010-01-01

    We have analyzed the rotational broadening and chromospheric activity in a sample of 123 M-dwarfs, using spectra taken at the W.M. Keck Observatory as part of the California Planet Search program. We find that only seven of these stars are rotating more rapidly than our detection threshold of v sin i ∼ 2.5 km s -1 . Rotation appears to be more common in stars later than M3 than in the M0-M2.5 mass range: we estimate that less than 10% of early-M stars are detectably rotating, whereas roughly a third of those later than M4 show signs of rotation. These findings lend support to the view that rotational braking becomes less effective in fully convective stars. By measuring the equivalent widths of the Ca II H and K lines for the stars in our sample, and converting these to approximate L Ca /L bol measurements, we also provide constraints on the connection between rotation and magnetic activity. Measurable rotation is a sufficient, but not necessary condition for activity in our sample: all the detectable rotators show strong Ca II emission, but so too do a small number of non-rotating stars, which we presume may lie at high inclination angles relative to our line of sight. Our data are consistent with a 'saturation-type' rotation-activity relationship, with activity roughly independent of rotation above a threshold velocity of less than 6 km s -1 . We also find weak evidence for a 'gap' in L Ca /L bol between a highly active population of stars, which typically are detected as rotators, and another much less active group.

  20. Comparison of FTIR Spectra of Bulk and Acid Residual Organic Matter in Chondrites

    Science.gov (United States)

    Kebukawa, Y.; Alexander, C. M. O'D.; Cody, G. D.

    2013-09-01

    We compared infrared spectra of bulk meteorites and IOM. The CH_2/CH_3 ratios show some difference between bulk samples and IOM, but there is no systematic correlation with chondrite groups or petrologic type.

  1. Phase 1 sampling and analysis plan for the 304 Concretion Facility closure activities

    International Nuclear Information System (INIS)

    Adler, J.G.

    1994-01-01

    This document provides guidance for the initial (Phase 1) sampling and analysis activities associated with the proposed Resource Conservation and Recovery Act of 1976 (RCRA) clean closure of the 304 Concretion Facility. Over its service life, the 304 Concretion Facility housed the pilot plants associated with cladding uranium cores, was used to store engineering equipment and product chemicals, was used to treat low-level radioactive mixed waste, recyclable scrap uranium generated during nuclear fuel fabrication, and uranium-titanium alloy chips, and was used for the repackaging of spent halogenated solvents from the nuclear fuels manufacturing process. The strategy for clean closure of the 304 Concretion Facility is to decontaminate, sample (Phase 1 sampling), and evaluate results. If the evaluation indicates that a limited area requires additional decontamination for clean closure, the limited area will be decontaminated, resampled (Phase 2 sampling), and the result evaluated. If the evaluation indicates that the constituents of concern are below action levels, the facility will be clean closed. Or, if the evaluation indicates that the constituents of concern are present above action levels, the condition of the facility will be evaluated and appropriate action taken. There are a total of 37 sampling locations comprising 12 concrete core, 1 concrete chip, 9 soil, 11 wipe, and 4 asphalt core sampling locations. Analysis for inorganics and volatile organics will be performed on the concrete core and soil samples. Separate concrete core samples will be required for the inorganic and volatile organic analysis (VOA). Analysis for inorganics only will be performed on the concrete chip, wipe, and asphalt samples

  2. Sources of variability in the determination by evaporation method of gross alpha activity in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Corbacho, J.A. [LARUEX, Caceres (Spain). Environmental Radioactivity Lab.

    2013-07-01

    Determining the gross alpha activity concentration of water samples is one way to screen for waters whose radionuclide content is so high that its consumption could imply surpassing the Total Indicative Dose as defined in European Directive 98/83/EC. One of the most commonly used methods to prepare the sources to measure gross alpha activity in water samples is desiccation. Its main advantages are the simplicity of the procedure, the low cost of source preparation, and the possibility of simultaneously determining the gross beta activity. The preparation of the source, the construction of the calibration curves, and the measurement procedure itself involve, however, various factors that may introduce sufficient variability into the results to significantly affect the screening process. We here identify the main sources of this variability, and propose specific procedures to follow in the desiccation process that will reduce the uncertainties, and ensure that the result is indeed representative of the sum of the activities of the alpha emitters present in the sample. (orig.)

  3. Determination of specific activity of americium and plutonium in selected environmental samples

    International Nuclear Information System (INIS)

    Trebunova, T.

    1999-01-01

    The aim of this work was development of method for determination of americium and plutonium in environmental samples. Developed method was evaluated on soil samples and after they was applied on selected samples of fishes (smoked mackerel, herring and fillet from Alaska hake). The method for separation of americium is based on liquid separation with Aliquate-336, precipitation with oxalic acid and using of chromatographic material TRU-Spec TM .The intervals of radiochemical yields were from 13.0% to 80.9% for plutonium-236 and from 10.5% to 100% for americium-241. Determined specific activities of plutonium-239,240 were from (2.3 ± 1.4) mBq/kg to (82 ± 29) mBq/kg, the specific activities of plutonium-238 were from (14.2 ± 3.7) mBq/kg to (708 ± 86) mBq/kg. The specific activities of americium-241 were from (1.4 ± 0.9) mBq/kg to (3360 ± 210) mBq/kg. The fishes from Baltic Sea as well as from North Sea show highest specific activities then fresh-water fishes from Slovakia. Therefore the monitoring of alpha radionuclides in foods imported from territories with nuclear testing is recommended

  4. Determination of phosphorus in biological samples by thermal neutron activation followed by β--counting

    International Nuclear Information System (INIS)

    Weginwar, R.G.; Samudralwar, D.L.; Garg, A.N.

    1989-01-01

    Phosphorus was determined using the β - emitter 32 P by instrumental neutron activation analysis (INAA) in several NBS and IAEA standards, and in samples of biological origin such as human and animal blood, cancerous tissue, edible plant leaves, diets, milk samples, etc. The method involves thermal neutron irradiation (for 2-10 h in a reactor) followed by β - counting on an end-window gas flow proportional counter using aluminium filter. The results are within ±10% of the certified values in most cases. (author) 29 refs.; 3 tabs

  5. Determination of total alpha and beta activities on vegetable samples by LSC

    International Nuclear Information System (INIS)

    Nogueira, Regina Apolinaria; Santos, Eliane Eugenia dos; Bakker, Alexandre Pereira; Vavassori, Giullia

    2011-01-01

    Gross alpha and beta analyses are screening techniques used for environmental radioactivity monitoring. The present study proposes to determine the gross alpha and beta activities in vegetable samples by using LSC - liquid scintillation spectrometry. The procedure was applied to vegetable foods. After ashing vegetable samples in a muffle furnace, 100 mg of ash were added to gel mixture of scintillation cocktails, Water - Instagel - Ultima Gold AB (6:10:4) ml, in polyethylene vial. Am-241 standard solution and a KCl (K-40) solution were used to determine the counting configuration, alpha/beta efficiencies and spillover

  6. Airborne radon-222 measurement by active sampling with charcoal adsorption and gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Shizuma, Kiyoshi; Wen, Xiao-qiong; Fukami, Kenji; Iwatani, Kazuo; Hamanaka, Shun-ichi

    1998-01-01

    A simple method for measuring radon concentration in air is presented. Airborne radon is adsorbed in a charcoal bed by an active air sampling. In time, the adsorbed radon comes to attain radioactive equilibrium with its short-lived progeny 214 Pb. Utilizing this fact, radon concentration is derived from γ-ray measurement of 214 Pb. This method is estimated to be capable of detecting radon concentration in air down to 0.79 Bq·m -3 . The adsorption coefficient obtained with the method is compared with what is obtainable with passive sampling. Applications of this method to indoor and outdoor radon measurements are described. (author)

  7. Determination of Na, Cl, Ca, Mg, Mn and K in milk samples by activation analysis

    International Nuclear Information System (INIS)

    Kira, Carmen S.; Maihara, Vera A.

    2000-01-01

    In the present work cow milk samples distributed for Sao Paulo government institutions, by means of the 'Viva leite' programme, have been monitored. The concentrations of Ca, Cl, K, Mg, Mn and Na were determined in five milk samples and in three different kinds of commercial powder milk, by instrumental neutron activation. For quality control, the reference materials NIST whole milk powder and non fat milk powder were analysed. The results obtained are in the range of the concentrations mentioned in the literature for these elements. (author)

  8. Trace aluminium determination and sampling problems of archeological bone employing destructive neutron activation analysis

    International Nuclear Information System (INIS)

    Blotcky, A.J.; Rack, E.P.; Recker, R.R.; Leffler, J.A.; Teitelbaum, S.

    1978-01-01

    A destructive neutron activation analysis procedure was developed for determining trace aluminium content in bone. The method is based on a carefully planned sample preparation, irradiation at a neutron flux for 3.1x10 11 nxcm -2 xs -1 for 5 minutes, and chemical separation based on ion exchange. It was found that bone samples soaked in aluminium containing soil gave highly elevated aluminium values as a result of the aluminium adsorption into the bone matrix. The maximum aluminium content values for prehistoric bones are larger than those of modern bones and comparable to aluminium levels present in bone from renal patients. (T.G.)

  9. Self-shielding coefficient and thermal flux depression factor of voluminous sample in neutron activation analysis

    International Nuclear Information System (INIS)

    Noorddin Ibrahim; Rosnie Akang

    2009-01-01

    Full text: One of the major problems encountered during the irradiation of large inhomogeneous samples in performing activation analysis using neutron is the perturbation of the neutron field due to absorption and scattering of neutron within the sample as well as along the neutron guide in the case of prompt gamma activation analysis. The magnitude of this perturbation shown by self-shielding coefficient and flux depression depend on several factors including the average neutron energy, the size and shape of the sample, as well as the macroscopic absorption cross section of the sample. In this study, we use Monte Carlo N-Particle codes to simulate the variation of neutron self-shielding coefficient and thermal flux depression factor as a function of the macroscopic thermal absorption cross section. The simulation works was carried out using the high performance computing facility available at UTM while the experimental work was performed at the tangential beam port of Reactor TRIGA PUSPATI, Malaysia Nuclear Agency. The neutron flux measured along the beam port is found to be in good agreement with the simulated data. Our simulation results also reveal that total flux perturbation factor decreases as the value of absorption increases. This factor is close to unity for low absorbing sample and tends towards zero for strong absorber. In addition, sample with long mean chord length produces smaller flux perturbation than the shorter mean chord length. When comparing both the graphs of self-shielding factor and total disturbance, we can conclude that the total disturbance of the thermal neutron flux on the large samples is dominated by the self-shielding effect. (Author)

  10. Phosphatase activity in Antarctica soil samples as a biosignature of extant life

    Science.gov (United States)

    Sato, Shuji; Itoh, Yuki; Takano, Yoshinori; Fukui, Manabu; Kaneko, Takeo; Kobayashi, Kensei

    Microbial activities have been detected in such extreme terrestrial environments as deep lithosphere, a submarine hydrothermal systems, stratosphere, and Antarctica. Microorganisms have adapted to such harsh environments by evolving their biomolecules. Some of these biomolecules such as enzymes might have different characteristics from those of organisms in ordinary environments. Many biosignatures (or biomarkers) have been proposed to detect microbial activities in such extreme environments. A number of techniques are proposed to evaluate biological activities in extreme environments including cultivation methods, assay of metabolism, and analysis of bioorganic compounds like amino acids and DNA. Enzyme activities are useful signature of extant life in extreme environments. Among many enzymes, phosphatase could be a good indicator of biological activities, since phosphate esters are essential for all the living terrestrial organisms. In addition, alkaline phosphatase is known as a typical zinc-containing metalloenzyme and quite stable in environments. We analyzed phosphatase activities in Antarctica soil samples to see whether they can be used as biosignatures for extant life. In addition, we characterized phosphatases extracted from the Antarctica soil samples, and compared with those obtained from other types of environments. Antarctica surface environments are quite severe environments for life since it is extremely cold and dry and exposed to strong UV and cosmic rays. We tried to evaluate biological activities in Antarctica by measuring phosphatase activities. Surface soil samples are obtained at the Sites 1-8 near Showa Base in Antarctica during the 47th Japan Antarctic exploration mission in 2005-6. Activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) are measured spectrophotometrically after mixing the powdered sample and p-nitrophenyl phosphate solution (pH 6.5 for ACP, pH 8.0 for ALP). ALP was characterized after extraction from soils with

  11. Predicting Antitumor Activity of Peptides by Consensus of Regression Models Trained on a Small Data Sample

    Directory of Open Access Journals (Sweden)

    Ivanka Jerić

    2011-11-01

    Full Text Available Predicting antitumor activity of compounds using regression models trained on a small number of compounds with measured biological activity is an ill-posed inverse problem. Yet, it occurs very often within the academic community. To counteract, up to some extent, overfitting problems caused by a small training data, we propose to use consensus of six regression models for prediction of biological activity of virtual library of compounds. The QSAR descriptors of 22 compounds related to the opioid growth factor (OGF, Tyr-Gly-Gly-Phe-Met with known antitumor activity were used to train regression models: the feed-forward artificial neural network, the k-nearest neighbor, sparseness constrained linear regression, the linear and nonlinear (with polynomial and Gaussian kernel support vector machine. Regression models were applied on a virtual library of 429 compounds that resulted in six lists with candidate compounds ranked by predicted antitumor activity. The highly ranked candidate compounds were synthesized, characterized and tested for an antiproliferative activity. Some of prepared peptides showed more pronounced activity compared with the native OGF; however, they were less active than highly ranked compounds selected previously by the radial basis function support vector machine (RBF SVM regression model. The ill-posedness of the related inverse problem causes unstable behavior of trained regression models on test data. These results point to high complexity of prediction based on the regression models trained on a small data sample.

  12. A Bayesian approach to assess data from radionuclide activity analyses in environmental samples

    International Nuclear Information System (INIS)

    Barrera, Manuel; Lourdes Romero, M.; Nunez-Lagos, Rafael; Bernardo, Jose M.

    2007-01-01

    A Bayesian statistical approach is introduced to assess experimental data from the analyses of radionuclide activity concentration in environmental samples (low activities). A theoretical model has been developed that allows the use of known prior information about the value of the measurand (activity), together with the experimental value determined through the measurement. The model has been applied to data of the Inter-laboratory Proficiency Test organised periodically among Spanish environmental radioactivity laboratories that are producing the radiochemical results for the Spanish radioactive monitoring network. A global improvement of laboratories performance is produced when this prior information is taken into account. The prior information used in this methodology is an interval within which the activity is known to be contained, but it could be extended to any other experimental quantity with a different type of prior information available

  13. Tritium Activity Measurement of Water Samples Using Liquid Scintillation Counter and Electrolytical Enrichment

    International Nuclear Information System (INIS)

    Baresic, J.; Krajcar Bronic, I.; Horvatincic, N.; Obelic, B.; Sironic, A.; Kozar-Logar J.

    2011-01-01

    Tritium (3H) activity of natural waters (precipitation, groundwater, surface waters) has recently become too low to be directly measured by low-level liquid scintillation (LSC) techniques. It is therefore necessary to perform electrolytical enrichment of tritium in such waters prior to LSC measurements. Electrolytical enrichment procedure has been implemented at the Rudjer Boskovic Institute (RBI) Tritium Laboratory in 2008, and since then 19 electrolyses have been completed. The mean enrichment factor E (a ratio between the final and initial 3H activities) after stabilisation of the system is E R BI = 22.5 @ 0.5, and the mean enrichment parameter (which describes the process of water mass reduction during electrolysis) is P R BI 0.949 @ 0.003. These values are comparable with those obtained at the Jo@ef Stefan Institute (JSI) Laboratory for liquid scintillation counting, at the electrolysis equipment of the same producer (AGH University of Science and Technology, Krakow, Poland) after 66 electrolyses carried out under identical conditions since 2007: E J SI = 18.9 @ 1.5, and P J SI = 0.896 @ 0.021. Both RBI and JSI laboratories have Ultra-low-level LSC Quantulus 1220 (Wallac, PerkinElmer) for measurement of 3H activity. A set of water samples having 3H activities in the range from 0 TU (''dead-water'' samples) to 18 000 TU (1 TU 0.118 Bq/L) were measured at both laboratories. Samples having 3H activity <200 TU were electrolytically enriched, while the others were measured directly in LSC. A very good agreement was obtained (correlation coefficient 0.991). Both laboratories participated in the IAEA TRIC2008 international intercomparison exercise. The analyses of reported 3H activity results in terms of z and u parameters showed that all results in both laboratories were acceptable. (author)

  14. Activity measurement of tritium in biological samples by azeotropic distillation liquid scintillation counter

    International Nuclear Information System (INIS)

    Wu Zongmei; Zheng Xiaomin

    1994-01-01

    The authors introduced a method of extracting tissue free water tritium (TFWT) in biological samples by azeotropic distillation with toluene and of measuring its activity by liquid scintillation counter. Measured TFWT recovery ratios of pine needles (fresh), green vegetables, radish, milk, meat, rice are 0.90, 0.95, 0.95, 0.85, 0.53 and 0.90; and the activities of TFWT are 1.8, 3.2, 1.8, 4.0, 3.3 and 2.7 Bq/L, respectively

  15. Determination of alpha activity produced by Indian tea samples using solid state nuclear track detection technique

    International Nuclear Information System (INIS)

    Azam, Ameer; Naqvi, A.H.; Srivastava, D.S.

    2001-01-01

    India has first place in the world in the production, consumption and export of tea. The average production of tea in India is about 780 million kg annually. Indian population uses tea as a favourite beverage specially with the breakfast. Tea leaves are perennial plants and they have extension root system spread over deeper layers in the soil. Soil contains uranium as trace element. Hence, uranium is transferred to the leaves as a result of uptake from the soil over the years. Since many of the decay products of uranium are alpha emitters hence tea is a source of alpha radioactivity and can cause damaging effects. Therefore, data on alpha activity of tea samples will be useful in estimating these harmful effects at least qualitatively. In the present study the alpha activity produced by thirteen samples of tea available in the local market was measured

  16. Determination of Iron and Nickel in Geological Samples by Activation Analysis with Reactor Fast Neutrons

    International Nuclear Information System (INIS)

    El Abd, A.

    2009-01-01

    Threshold reactions induced by reactor fast neutrons are well recognized. The concentration of Fe and Ni were determined in nine geological samples by activation analysis with reactor fast neutrons using the threshold reactions 5 4F e( n,p) 54 Mn and 58 Ni ( n, p )'5 8 Co respectively. The fast neutron flux was determined using the reactions 92 Mo(n, 2n) 92 mNb and 95 Mo(n,p) 95 Nb. The determined concentration of Fe and Ni in the samples were checked by determining them in the GSJ JB-1 reference material using the same , ( p, n) reactions. There are a good agreement between the measured and recommended values. The concentrations of Fe were also determined by the ) , ( n, γ) capture reactions in the geological samples and the JB-1 reference material using the K θ - NAA method. There are good agreements between the determined concentrations from the ) , ( p, n) and the ( γ, n) reactions.

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  18. Pretreatment procedures applied to samples to be analysed by neutron activation analysis at CDTN/CNEN

    International Nuclear Information System (INIS)

    Francisco, Dovenir; Menezes, Maria Angela de Barros Correia

    2009-01-01

    The neutron activation technique - using several methods - has been applied in 80% of the analytical demand of Division for Reactor and Analytical Techniques at CDTN/CNEN, Belo Horizonte, Minas Gerais. This scenario emphasizes the responsibility of the Laboratory to provide and assure the quality of the measurements. The first step to assure the results quality is the preparation of the samples. Therefore, this paper describes the experimental procedures adopted at CDTN/CNEN in order to uniform conditions of analysis and to avoid contaminations by elements present everywhere. Some of the procedures are based on methods described in the literature; others are based on many years of experience preparing samples from many kinds of matrices. The procedures described are related to geological material - soil, sediment, rock, gems, clay, archaeological ceramics and ore - biological materials - hair, fish, plants, food - water, etc. Analytical results in sediment samples are shown as n example pointing out the efficiency of the experimental procedure. (author)

  19. [Hygienic evaluation of the total mutagenic activity of snow samples from Magnitogorsk].

    Science.gov (United States)

    Legostaeva, T B; Ingel', F I; Antipanova, N A; Iurchenko, V V; Iuretseva, N A; Kotliar, N N

    2010-01-01

    The paper gives the results of 4-year monitoring of the total mutagenic activity of snow samples from different Magnitogork areas in a test for induction of dominant lethal mutations (DLM) in the gametes of Drosophila melanogaster. An association was first found between the rate of DLM and the content of some chemical compounds in the ambient air and snow samples; moreover all the substances present in the samples, which had found genotoxic effects, showed a positive correlation with the rate of DLM. Furthermore, direct correlations were first established between the rate of DLM and the air pollution index and morbidity rates in 5-7-year-old children residing in the areas under study. The findings allow the test for induction of dominant lethal mutations (DLM) in the gametes of Drosophila melanogaster to be recommended due to its unique informative and prognostic value for monitoring ambient air pollution and for extensive use in the risk assessment system.

  20. Determination of sodium in biological samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Parwate, D.V.; Garg, A.N.

    1981-01-01

    Sodium is one of the most essential elements needed for metabolic processes amongst human beings. It is consumed in the form of sodium chloride but it is also present in edible plant leaves. Sodium is mostly analyzed by flame photometric method, a destructive and time consuming technique. Sodium has been determined in some green leave vegetables samples-palak, radish, khatta palak (ambat chuka), chaulai leaves, chauli bean covers and its seeds by instrumental neutron activation analysis. The method involves irradiation of samples with thermal neutrons from 241 Am-Be source and counting 24 Na activity (half life 15 hr) from the reaction 23 Na(n,γ) 24 Na. Activity due to 1.37 MeV photopeak was counted with a NaI(Tl) crystal coupled to gamma ray spectrometer. Green leaves of the vegetables were thoroughly washed, dried at constant temperature and powdered. Bowen's Kale powder was used as standard for measuring sodium abundances. About 2g each of samples and the standard were packed in polythene vials. They were irradiated for 24 hrs, delayed by 1 hr and then counted for 20 mts. It is found that radish leaves are most enriched in sodium (14.0 +-0.45%) amongst four leave samples analyzed. For three different parts of chaulai leaves, bean covers and seeds, sodium contents are 1.38%, 1820 and 1010 ppm. Palak contains 2.84 +-0.29% while khatta palak contains only 4210 +- 830 ppm sodium. All values reported here are for dry weight samples and are means of three replicate measurements with standard deviation. (author)

  1. Derivative activation analysis of phosphorus at ppb levels in water samples

    International Nuclear Information System (INIS)

    Arunachalam, J.; John, A.; Gangadharan, S.

    1991-01-01

    A neutron activation analysis procedure has been developed for the indirect determination of phosphorus as orthophosphate at ppb levels, via the formation of antimonyl phosphomolybdic acid. The complex is adsorbed on Sephadex G-25 resin and the antimony is estimated through NAA, allowing the determination of phosphorus. The procedure provides an easy method to adopt for the routine determination of phosphorus at ≥ 10 ng ml -1 levels with good precision, in water samples. (author) 6 refs.; 5 tabs

  2. Sampling and instrumentation requirements for long-range D and D activities at INEL

    International Nuclear Information System (INIS)

    Ahlquist, A.J.

    1985-01-01

    Assistance was requested to help determine sampling and instrumentation requirements for the long-range decontamination and decommissioning activities at the Idaho National Engineering Laboratory. Through a combination of literature review, visits to other DOE contractors, and a determination of the needs for the INEL program, a draft report has been prepared that is now under review. The final report should be completed in FY 84

  3. Quality control on the accuracy of the total Beta activity index in different sample matrices water

    International Nuclear Information System (INIS)

    Pujol, L.; Pablo, M. A. de; Payeras, J.

    2013-01-01

    The standard ISO/IEC 17025:2005 of general requirements for the technical competence of testing and calibration laboratories, provides that a laboratory shall have quality control procedures for monitoring the validity of tests and calibrations ago. In this paper, the experience of Isotopic Applications Laboratory (CEDEX) in controlling the accuracy rate of total beta activity in samples of drinking water, inland waters and marine waters is presented. (Author)

  4. Geochemical signature of land-based activities in Caribbean coral surface samples

    Science.gov (United States)

    Prouty, N.G.; Hughen, K.A.; Carilli, J.

    2008-01-01

    Anthropogenic threats, such as increased sedimentation, agrochemical run-off, coastal development, tourism, and overfishing, are of great concern to the Mesoamerican Caribbean Reef System (MACR). Trace metals in corals can be used to quantify and monitor the impact of these land-based activities. Surface coral samples from the MACR were investigated for trace metal signatures resulting from relative differences in water quality. Samples were analyzed at three spatial scales (colony, reef, and regional) as part of a hierarchical multi-scale survey. A primary goal of the paper is to elucidate the extrapolation of information between fine-scale variation at the colony or reef scale and broad-scale patterns at the regional scale. Of the 18 metals measured, five yielded statistical differences at the colony and/or reef scale, suggesting fine-scale spatial heterogeneity not conducive to regional interpretation. Five metals yielded a statistical difference at the regional scale with an absence of a statistical difference at either the colony or reef scale. These metals are barium (Ba), manganese (Mn), chromium (Cr), copper (Cu), and antimony (Sb). The most robust geochemical indicators of land-based activities are coral Ba and Mn concentrations, which are elevated in samples from the southern region of the Gulf of Honduras relative to those from the Turneffe Islands. These findings are consistent with the occurrence of the most significant watersheds in the MACR from southern Belize to Honduras, which contribute sediment-laden freshwater to the coastal zone primarily as a result of human alteration to the landscape (e.g., deforestation and agricultural practices). Elevated levels of Cu and Sb were found in samples from Honduras and may be linked to industrial shipping activities where copper-antimony additives are commonly used in antifouling paints. Results from this study strongly demonstrate the impact of terrestrial runoff and anthropogenic activities on coastal water

  5. Phenolic profiles and antioxidant activity of Turkish Tombul hazelnut samples (natural, roasted, and roasted hazelnut skin).

    Science.gov (United States)

    Pelvan, Ebru; Olgun, Elmas Öktem; Karadağ, Ayşe; Alasalvar, Cesarettin

    2018-04-01

    The phenolic profiles and antioxidant status of hazelnut samples [natural (raw) hazelnut, roasted hazelnut, and roasted hazelnut skin] were compared. Free and bound (ester-linked and glycoside-linked) phenolic acids were examined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comprehensive identification of phenolics was carried out using Q-exactive hybrid quadrupole-orbitrap mass spectrometer (Q-OT-MS). Samples were also assessed for their total phenolics and antioxidant activities using three different assays. Ten free and bound phenolic acids were quantified in hazelnut samples. Roasted hazelnut skin contained the highest content of total phenolic acids, followed by natural and roasted hazelnuts. The majority of phenolic acids were present in the bound form. Using a Q-OT-MS, 22 compounds were tentatively identified, 16 of which were identified for the first time in hazelnut samples. The newly identified compounds consisted of flavonoids, phenolic acids and related compounds, hydrolysable tannins and related compounds, and other phenolics. Three antioxidant assays demonstrated similar trends that roasted hazelnut skin rendered the highest activity. The present work suggests that roasted hazelnut skin is a rich source of phenolics and can be considered as a value-added co-product for use as functional food ingredient and antioxidant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Maintenance of stability in γ spectrometric system of low active and environmental samples - a practical experience

    International Nuclear Information System (INIS)

    Ravishankar, R.; Bandyopadhyay, T.; Sarkar, P.K.

    2011-01-01

    Particle Accelerators are becoming part of the society with more and more medical and Industrial types are added every year in addition to research type of accelerators. The outflow of materials to the public domain from such accelerator facilities need to checked carefully and must be released after ensuring the activities of such materials should not exceed the regulatory limits. Health Physics Unit, VECC is involved in analyzing food product samples, seized samples which are suspected to contain Uranium etc and other environmental samples in addition to analyzing radioactive materials evolved from Operational Health Physics work. Most of these analyses involve γ Spectrometric Systems of high efficiency and high resolution types. The efficacy of the analysis and results depends on various parameters of the spectrometric system. The electrical noise from the power supply system and other noises picked up, even in the range of a few milli volts range, have been found to affect the stability of the system. These effects may not be present initially during installation but may creep in due course due to various reasons including weather conditions, wear and tear etc. Unless these problems are attended in regular intervals, the stability of the spectrometric systems and hence the results of analysis of the low active and environmental samples, will not be satisfactory. The work describes the practical problems faced by Health Physics Unit, the methods employed in identifying the problems, the necessary remedial measures taken, the final outcome in the stability and the procedures framed in order to avoid in future. (author)

  7. Neutron activation analysis of core and drill cutting samples from geothermal well drilling

    International Nuclear Information System (INIS)

    Miller, G.E.

    1986-01-01

    Samples of sandstones and shales were analysed by instrumental neutron activation analysis for a total of 30 elements. Three irradiation and five counting periods were employed. Solutions and National Bureau of Standards Reference Materials were used for comparison. The samples were obtained from drill cuttings (with a few core samples) from drillings in the Salton Sea geothermal field of California. These determinations form part of a major study to establish elemental variation as a function of mineral variation as depth and temperature in the well vary. The overall goal is to examine mineral alteration and/or element migration under typical geothermal conditions. The techniques involve typical compromises between maximizing precision for individual element determinations and the amount of time and effort that can be expended, as it is desired to examine large numbers of samples. With the limitations imposed by the reactor flux available at the U.C.Irvine TRIGA reactor, the detectors available, and time factors, most precisions are acceptable for geological comparison purposes. Some additional measurements were made by delayed-neutron counting methods to compare with uranium determinations made by conventional instrumental neutron activation analysis methods. (author)

  8. Ti-dopant-enhanced photocatalytic activity of a CaFe{sub 2}O{sub 4}/MgFe{sub 2}O{sub 4} bulk heterojunction under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Borse, Pramod H. [International Advanced Research Center for Powder Metallurgy and New Materials, Hyderabad (India); Kim, Jae Y.; Lee, Jae S. [Pohang University of Science and Technology, Pohang (Korea, Republic of); Lim, Kwon T. [Pukyong National University, Busan (Korea, Republic of); Jeong, Euh D.; Bae, Jong S.; Yoon, Jang H.; Yu, Seong M.; Kim, Hyun G. [Korea Basic Science Institute, Busan (Korea, Republic of)

    2012-07-15

    The effect substitution of Ti{sup 4+} at the Fe{sup 3+} site in a CaFe{sub 2}O{sub 4{sup -}}MgFe{sub 2}O{sub 4} bulk hetero-junction (BH) lattice photocatalyst was explored and the Ti ion concentration was optimized to fabricate an efficient photocatalyst. A BH consisting of an optimum dopant concentration (Ti{sup +4}) level of x = 0.03 exhibited an increased band gap and generated a 1.5 times higher photocurrent. The newly fabricated Ti ion doped photocatalyst showed an enhanced quantum yield (up to ∼13.3%) for photodecomposition of a H{sub 2}O-CH{sub 3}OH mixture, as compared to its undoped BH counterpart under visible light (λ ≥ 420 nm). In contrast, the material doped with a very high Ti-dopant concentration displayed deteriorated photochemical properties. An efficient charge-separation induced by Ti-ion doping seems to be responsible for the higher photocatalytic activity in a doped bulk BH.

  9. Test of methods for retrospective activity size distribution determination from filter samples

    International Nuclear Information System (INIS)

    Meisenberg, Oliver; Tschiersch, Jochen

    2015-01-01

    Determining the activity size distribution of radioactive aerosol particles requires sophisticated and heavy equipment, which makes measurements at large number of sites difficult and expensive. Therefore three methods for a retrospective determination of size distributions from aerosol filter samples in the laboratory were tested for their applicability. Extraction into a carrier liquid with subsequent nebulisation showed size distributions with a slight but correctable bias towards larger diameters compared with the original size distribution. Yields in the order of magnitude of 1% could be achieved. Sonication-assisted extraction into a carrier liquid caused a coagulation mode to appear in the size distribution. Sonication-assisted extraction into the air did not show acceptable results due to small yields. The method of extraction into a carrier liquid without sonication was applied to aerosol samples from Chernobyl in order to calculate inhalation dose coefficients for 137 Cs based on the individual size distribution. The effective dose coefficient is about half of that calculated with a default reference size distribution. - Highlights: • Activity size distributions can be recovered after aerosol sampling on filters. • Extraction into a carrier liquid and subsequent nebulisation is appropriate. • This facilitates the determination of activity size distributions for individuals. • Size distributions from this method can be used for individual dose coefficients. • Dose coefficients were calculated for the workers at the new Chernobyl shelter

  10. Understanding active sampling strategies: Empirical approaches and implications for attention and decision research.

    Science.gov (United States)

    Gottlieb, Jacqueline

    2018-05-01

    In natural behavior we actively gather information using attention and active sensing behaviors (such as shifts of gaze) to sample relevant cues. However, while attention and decision making are naturally coordinated, in the laboratory they have been dissociated. Attention is studied independently of the actions it serves. Conversely, decision theories make the simplifying assumption that the relevant information is given, and do not attempt to describe how the decision maker may learn and implement active sampling policies. In this paper I review recent studies that address questions of attentional learning, cue validity and information seeking in humans and non-human primates. These studies suggest that learning a sampling policy involves large scale interactions between networks of attention and valuation, which implement these policies based on reward maximization, uncertainty reduction and the intrinsic utility of cognitive states. I discuss the importance of using such paradigms for formalizing the role of attention, as well as devising more realistic theories of decision making that capture a broader range of empirical observations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Determination of iodine 129 in environmental samples from Austria by neutron activation analysis

    International Nuclear Information System (INIS)

    Karg, V.; Schoenfeld, T.

    1986-11-01

    For various types of samples (thyroids from humans, from game and cows; ground water, snow and air filters) the 129 I-contents, expressed as 129 I/ 127 I-ratio (R), were determined by neutron activation analysis. The method utilises the neutron induced reactions 129 I(n, γ) 130 I and 127 I(n, 2n) 126 I. Four main steps are involved: 1. Separation of iodine from the sample and conversion to a form suitable for neutron irradiation. 2. Irradiation in a reactor. 3. Chemical processing of the irradiated material, i.e. separation of radio-iodine with addition of carrier. 4. Measurement of activities of 130 I and 126 I with a gammaspectrometer. The 129 I/ 127 I-ratio (R) is then obtained by comparing with the activities produced in a reference sample (usually with R = 1.0 x 10 -8 ) which is irradiated simultaneously. Details of the method are presented in the report. R-values between 0.6 x 10 -8 and 39 x 10 -8 were found. The highest values were those of snow and game thyroids. Ground water contained very little 129 I. The results confirm the expectation that 129 I enters the biosphere mainly via air and precipitation. (Author)

  12. Activity level of gross α and gross β in airborne aerosol samples around the Qinshan NPP

    International Nuclear Information System (INIS)

    Chen Bin; Ye Jida; Chen Qianyuan; Wu Xiaofei; Song Weili; Wang Hongfeng

    2007-01-01

    The monitoring results of gross α and gross 13 activity from 2001 to 2005 for environmental airborne aerosol samples around the Qinshan NPP base are presented in this paper. A total of 170 aerosol samples were collected from monitoring sites of Caichenmen village, Qinlian village, Xiajiawan village and Yangliucun village around the Qinshan NPP base. The measured specific activity of gross α and gross β are in the range of 0.02-0.38 mBq/m 3 and 0.10-1.81 mBq/m 3 , respectively, with an average of 0.11 mBq/m 3 and 0.45mBq/m 3 , respectively. They are lower than the average of 0.15 mBq/m 3 and 0.52 mBq/m 3 , of reference site at Hangzhou City. It is indicated that the specific activity of gross α and gross β for environmental aerosol samples around the Qinshan NPP base had not been increased in normal operating conditions of the NPP. (authors)

  13. A study on aluminum determination in environmental samples by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Noyori, Amanda

    2017-01-01

    Aluminum determinations are of great interest since this element is toxic to humans and it is widely distributed in the environment. Besides, the determinations of this element by conventional analytical methods present difficulties due to sample contamination during the analyses. Neutron activation analysis (NAA) for Al determination presents advantages of fast analyses and of high sensitivity. However, NAA of Al does present problems of P and Si nuclear reaction interferences. Aluminum is determined by measuring 28 Al, formed in the reaction 27 Al (n, γ) 28 Al, the same radioisotope formed in reactions 31 P (n, α) 28 Al and 28 Si (n, p) 28 Al. The purpose of this study was to determine Al in environmental samples by NAA correcting these interferences using correction factors, and determining P and Si concentrations in the samples. In this study, certified reference materials and biomonitor samples (tree barks and lichen) were analyzed. Experimental procedure consisted of irradiating an aliquot of the sample at the IEA-R1 nuclear research reactor together with Al standard, followed by gamma ray spectrometry. Phosphorus was determined by measuring beta radiation of 32 P using a Geiger-Müller counter. Silicon was determined by epithermal neutron activation analysis and measuring 29 Al formed in the reaction 29 Si (n, p) 29 Al. Results obtained in the determination of Al, P and Si in the certified reference materials showed good precision and accuracy with |Z-score| ≤ 2. Aluminum results in the biomonitor samples varied from to 253 to 15783 μg g -1 . In the case of P its concentrations varied from 283 to 1946 μg g -1 . Silicon determinations in biomonitors varied from 0.11 to 7.8 %. The interference contribution rates in the analyses of the biomonitor samples were of the order of 2.0 % and this contribution depends on the relation between concentrations of interfering elements and of Al in the sample. Detection limit values of Al in the biomonitor analyses

  14. Activity Concentration for Surface Soil Samples Collected from Arrant, Qena, Egypt

    International Nuclear Information System (INIS)

    Harb, S.; Salahel Din, K.; Abbady, A.; Moustafa, M.

    2010-01-01

    Soil samples were collected from four regions from Armant area. Qena, Upper Egypt for measure their natural radioactivity concentrations due to Ra-226, Th-232 and K-40 radionuclides. Thirty-Four surface soil samples were analyzed by using low-level gamma-spectrometric analysis. The average activity concentration for Ra-226 in (Bq/kg) in the collected soil samples were found to be 27.3 ±3.2, 11.4±1.09, 10.6±1.2, and 11.4±1.02 while the average value for Th-232 were 15.1±1.4, 11.1±0.77, 10.8 ± 0.72 and 11.1 ± 0.8 (Bq/kg) for soil samples from North, South, West and East. The corresponding average values for K-40 were 521.4±16.8, 463±14.8, 488.9±15.6 and 344.5±10.7 (Bq/kg), respectively. Based on radionuclides concentration in surface soil samples the radiological effects can be assessed

  15. Determination of uranium in tree bark samples by epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Lima, Nicole Pereira de; Saiki, Mitiko

    2017-01-01

    In this study uranium (U) concentrations were determined in certified reference materials (CRMs) and in tree bark samples collected in 'Cidade Universitaria Armando de Salles Oliveira' (CUASO) USP, Sao Paulo, SP, Brazil). The barks were collected from different species namely Poincianella pluviosa and Tipuana tipu. These bark samples were cleaned, dried, grated and milled for the analyses by epithermal neutron activation analysis method (ENAA). This method consists on irradiating samples and U standard in IEAR1 nuclear reactor with thermal neutron flux of 1:9 x 10 12 n cm -2 s -1 during 40 to 60 seconds depending on the samples matrices. The samples and standard were measured by gamma ray spectroscopy. U was identified by the peak of 74.66 keV of 239 U with half life of 23.47 minutes. Concentration of U was calculated by comparative method. For analytical quality control of U results, certified reference materials were analysed. Results obtained for CRMs presented good precision and accuracy, with |Z score| <= 0.39. Uranium concentrations in tree barks varied from 83.1 to 627.6 ng g - 1 and the relative standard deviations of these results ranged from 1.8 to 10%. (author)

  16. Determination of uranium in tree bark samples by epithermal neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Nicole Pereira de; Saiki, Mitiko, E-mail: mitiko@ipen.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    In this study uranium (U) concentrations were determined in certified reference materials (CRMs) and in tree bark samples collected in 'Cidade Universitaria Armando de Salles Oliveira' (CUASO) USP, Sao Paulo, SP, Brazil). The barks were collected from different species namely Poincianella pluviosa and Tipuana tipu. These bark samples were cleaned, dried, grated and milled for the analyses by epithermal neutron activation analysis method (ENAA). This method consists on irradiating samples and U standard in IEAR1 nuclear reactor with thermal neutron flux of 1:9 x 10{sup 12} n cm{sup -2} s{sup -1} during 40 to 60 seconds depending on the samples matrices. The samples and standard were measured by gamma ray spectroscopy. U was identified by the peak of 74.66 keV of {sup 239}U with half life of 23.47 minutes. Concentration of U was calculated by comparative method. For analytical quality control of U results, certified reference materials were analysed. Results obtained for CRMs presented good precision and accuracy, with |Z score| <= 0.39. Uranium concentrations in tree barks varied from 83.1 to 627.6 ng g{sup -} {sup 1} and the relative standard deviations of these results ranged from 1.8 to 10%. (author)

  17. Major and trace elements assessment in sediment samples from Rio Grande Reservoir, by neutron activation analysis

    International Nuclear Information System (INIS)

    Franklin, Robson L.; Ferreira, Francisco J.; Favaro, Deborah I.T.; Bevilacqua, Jose Eduardo

    2009-01-01

    The Rio Grande Reservoir, Southeast of the Sao Paulo Metropolitan Area (SPMA) supplies water for four counties (Sao Bernardo do Campo, Sao Caetano do Sul, Santo Andre and Diadema). It has been seriously affected by urban expansion, due to chaotic urban occupation and improper use of the surrounding areas. In this study bottom sediment samples were collected, by using a Van Veen sampler, during the dry and rainy seasons. Four sampling points were defined by using GPS and are located at the mouth of the Rio Grande and Ribeirao Pires Rivers, in the middle of the reservoir and near the catchment point of the water supply. The sediment samples were submitted to instrumental neutron activation analysis (INAA) and the following elements were determined: As, Ba, Br, Co, Cr, Cs, Rb, Sb, Sc, Se, Ta, Th, U e Zn and the rare earth elements Ce, Eu, La, Lu, Nd, Sm, Tb, Yb. Short irradiation was also performed for total Hg determination by NAA using 197 Hg radioisotope. This was possible due to the high Hg concentration levels in these sediments. The methodology validation was carried out by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and adopted by CETESB. (author)

  18. Sampling study in milk storage tanks by INAA

    International Nuclear Information System (INIS)

    Santos, L.G.C.; Nadai Fernandes de, E.A.; Bacchi, M.A.; Tagliaferro, F.S.

    2008-01-01

    This study investigated the representativeness of samples for assessing chemical elements in milk bulk tanks. Milk samples were collected from a closed tank in a dairy plant and from an open top tank in a dairy farm. Samples were analyzed for chemical elements by instrumental neutron activation analysis (INAA). For both experiments, Br, Ca, Cs, K, Na, Rb and Zn did not present significant differences between samples thereby indicating the appropriateness of the sampling procedure adopted to evaluate the analytes of interest. (author)

  19. Code Betal to calculation Alpha/Beta activities in environmental samples

    International Nuclear Information System (INIS)

    Romero, L.; Travesi, A.

    1983-01-01

    A codes, BETAL, was developed, written in FORTRAN IV, to automatize calculations and presentations of the result of the total alpha-beta activities measurements in environmental samples. This code performs the necessary calculations for transformation the activities measured in total counts, to pCi/1., bearing in mind the efficiency of the detector used and the other necessary parameters. Further more, it appraise the standard deviation of the result, and calculus the Lower limit of detection for each measurement. This code is written in iterative way by screen-operator dialogue, and asking the necessary data to perform the calculation of the activity in each case by a screen label. The code could be executed through any screen and keyboard terminal, (whose computer accepts Fortran IV) with a printer connected to the said computer. (Author) 5 refs

  20. Application of the neutron activation analysis method for determing trace elements in Brazilian food sample

    International Nuclear Information System (INIS)

    Maihara, V.A.; Vasconcellos, M.B.A.

    1988-01-01

    Recently there has been an increase of consciousness about the importance of trace elements in human health and disease as well as rising concern about food contamination. The development of sensitive, accurate and price methods is one of the most important of the knowledge of trace elements contents in foods and in biological samples. Neutron activation analysis is one of the most suitable tecniques because a great number of elements can be determined in concentrations in the range of μg/g to ng/g. The present work is a part of an AIEA Co-ordinated Research Programme on the applications of nuclear techniques for toxic elements in foodstuffs. Neutron activation analysis is applied to analysis of bread, milk powder and rice that are considered essential foods in the Brazilian diet. Some aspects of the activation analysis of biological matrices are discussed. (author) [pt

  1. Integration of bulk piezoelectric materials into microsystems

    Science.gov (United States)

    Aktakka, Ethem Erkan

    Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with integration of a 50-80% efficient power management IC, which incorporates a supply-independent bias circuitry, an active diode for low-dropout rectification, a bias-flip system for higher efficiency, and a trickle battery charger. The overall system does not require a pre-charged battery, and has power consumption of <1microW in active-mode (measured) and <5pA in sleep-mode (simulated). Under lg vibration at 155Hz, a 70mF ultra-capacitor is charged from OV to 1.85V in 50 minutes.

  2. Depression and physical activity in a sample of nigerian adolescents: levels, relationships and predictors

    Science.gov (United States)

    2011-01-01

    Background Physical inactivity is related to many morbidities but the evidence of its link with depression in adolescents needs further investigation in view of the existing conflicting reports. Methods The data for this cross-sectional study were collected from 1,100 Nigerian adolescents aged 12-17 years. Depressive symptomatology and physical activity were assessed using the Children's Depression Inventory (CDI) and the Physical Activity Questionnaire-Adolescent version (PAQ-A) respectively. Independent t tests, Pearson's Moment Correlation and Multi-level logistic regression analyses for individual and school area influences were carried out on the data at p < 0.05. Results The mean age of the participants was 15.20 ± 1.435 years. The prevalence of mild to moderate depression was 23.8%, definite depression was 5.7% and low physical activity was 53.8%. More severe depressive symptoms were linked with lower levels of physical activity (r = -0.82, p < 0.001) and moderate physical activity was linked with reduced risk of depressive symptoms (OR = 0.42, 95% CI = 0.29-0.71). The odds of having depressive symptoms were higher in older adolescents (OR = 2.16, 95% CI = 1.81-3.44) and in females (OR = 2.92, 95% CI = 1.82-3.54). Females had a higher risk of low physical activity than male adolescents (OR = 2.91, 95% CI = 1.51-4.26). Being in Senior Secondary class three was a significant predictor of depressive symptoms (OR = 3.4, 95% CI = 2.55-4.37) and low physical activity. Conclusions A sizable burden of depression and low physical activity existed among the studied adolescents and these were linked to both individual and school factors. Future studies should examine the effects of physical activity among clinical samples of adolescents with depression. PMID:21569581

  3. Smoking, activity level and exercise test outcomes in a young population sample without cardiopulmonary disease.

    Science.gov (United States)

    Vozoris, N T; O'donnell, D E

    2015-01-01

    Whether reduced activity level and exercise intolerance precede the clinical diagnosis of cardiopulmonary disorders in smokers is not known. We examined activity level and exercise test outcomes in a young population-based sample without overt cardiopulmonary disease, differentiating by smoking history. This was a multiyear cross-sectional study using United States National Health and Nutrition Examination Survey data from 1999-2004. Self-reported activity level and incremental exercise treadmill testing were obtained on survey participants ages 20-49 years, excluding individuals with cardio-pulmonary disease. Three thousand seven hundred and one individuals completed exercise testing. Compared to never smokers, current smokers with >10 pack years reported significantly higher odds of little or no recreation, sport, or physical activity (adjusted OR 1.62; 95% CI 1.12-2.35). Mean perceived exertion ratings (Borg 6-20) at an estimated standardized workload were significantly greater among current smokers (18.3-18.6) compared to never (17.3) and former smokers (17.9) (psmoking abstinence was associated with significantly lower likelihood of low estimated peak oxygen uptake categorization (psmoking cessation, these results set the stage for future studies that examine mechanisms of activity restriction in young smokers and the utility of measures of activity restriction in the earlier diagnosis of smoking-related diseases.

  4. Depression and physical activity in a sample of nigerian adolescents: levels, relationships and predictors

    Directory of Open Access Journals (Sweden)

    Okafor Nkechi C

    2011-05-01

    Full Text Available Abstract Background Physical inactivity is related to many morbidities but the evidence of its link with depression in adolescents needs further investigation in view of the existing conflicting reports. Methods The data for this cross-sectional study were collected from 1,100 Nigerian adolescents aged 12-17 years. Depressive symptomatology and physical activity were assessed using the Children's Depression Inventory (CDI and the Physical Activity Questionnaire-Adolescent version (PAQ-A respectively. Independent t tests, Pearson's Moment Correlation and Multi-level logistic regression analyses for individual and school area influences were carried out on the data at p Results The mean age of the participants was 15.20 ± 1.435 years. The prevalence of mild to moderate depression was 23.8%, definite depression was 5.7% and low physical activity was 53.8%. More severe depressive symptoms were linked with lower levels of physical activity (r = -0.82, p Conclusions A sizable burden of depression and low physical activity existed among the studied adolescents and these were linked to both individual and school factors. Future studies should examine the effects of physical activity among clinical samples of adolescents with depression.

  5. Mining the bulk positron lifetime

    International Nuclear Information System (INIS)

    Aourag, H.; Guittom, A.

    2009-01-01

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Active Listening Attitude Scale (ALAS: Reliability and Validity in a Nationwide Sample of Greek Educators

    Directory of Open Access Journals (Sweden)

    Ntina Kourmousi

    2017-03-01

    Full Text Available The present study examined the Active Listening Attitude Scale (ALAS validity and reliability in a sample of 3955 Greek educators. The sample was randomly split and an exploratory factor analysis (EFA was conducted in the even subsample to evaluate the scale’s construct validity. A confirmatory factor analysis (CFA was performed in the odd subsample to confirm the three-factor model identified by the EFA. The chi square test (χ2 of the model was significant (p < 0.05, due to the large sample size. The root mean square error of approximation (RMSEA, the comparative fit index (CFI and the goodness of fit index (GFI values were 0.079, 0.969 and 0.960, respectively, further supporting the fit of the three-factor model. Cronbach’s alpha coefficient was used to test internal consistency reliability and was satisfactory exceeding 0.72 for ALAS subscales. The intercorrelations of the three subscales were all positive and significant (p < 0.001, ranging from 0.20 to 0.42. Student’s t-tests and the computation of effect sizes revealed that women scored higher on Listening Skill and Conversation Opportunity, while principals and participants trained on mental health promotion scored higher on all three subscales. The analyses confirmed the three-factor model of ALAS and demonstrated its validity and reliability in measuring Greek teachers’ active listening attitudes.

  7. Fabrication of SERS Active Surface on Polyimide Sample by Excimer Laser Irradiation

    Directory of Open Access Journals (Sweden)

    T. Csizmadia

    2014-01-01

    Full Text Available A possible application of excimer laser irradiation for the preparation of surface enhanced Raman spectroscopy (SERS substrate is demonstrated. A polyimide foil of 125 μm thickness was irradiated by 240 pulses of focused ArF excimer laser beam (λ = 193 nm, FWHM = 20 ns. The applied fluence was varied between 40 and 80 mJ/cm2. After laser processing, the sample was coated with 40 nm silver by PLD in order to create a conducting layer required for the SERS application. The SERS activity of the samples was tested by Raman microscopy. The Raman spectra of Rhodamine 6G aqueous solution (c=10−3 mol/dm3 were collected from the patterned and metalized areas. For areas prepared at 40–60 mJ/cm2 laser fluences, the measured Raman intensities have shown a linear dependence on the applied laser fluence, while above 60 mJ/cm2 saturation was observed. The morphology of the SERS active surface areas was investigated by scanning electron microscopy. Finite element modeling was performed in order to simulate the laser-absorption induced heating of the polyimide foil. The simulation resulted in the temporal and spatial distribution of the estimated temperature in the irradiated polyimide sample, which are important for understanding the structure formation process.

  8. Antioxidant Activity of Three Honey Samples in relation with Their Biochemical Components

    Directory of Open Access Journals (Sweden)

    Lee Suan Chua

    2013-01-01

    Full Text Available The antioxidant activities based on the free radical scavenging, reducing power, and bleaching inhibition were investigated for the three commonly used honeys in Malaysia, namely, tualang, gelam, and acacia honey. The antioxidant capacity of the honey samples was correlated with their biochemical constituents such as total phenol, total flavonoid content, and total water-soluble vitamins (vitamin B1, B2, B3, B9, B12, and vitamin C. The total flavonoid content of honey samples was strongly correlated with the three antioxidative processes (–0.9910. In contrast, the total water-soluble vitamins was found to be well correlated with the free radical scavenging activity (. Vitamin B3 was likely to be in the highest concentration, which covered for 69–80% of the total vitamin content. A number of five phenolic acids, three flavonoids, and two organic acids had also been detected from the honey samples using UPLC-MS/MS, without sugar-removal procedure.

  9. Determination of trace elements in lichen samples by neutron activation analysis

    International Nuclear Information System (INIS)

    Saiki, Mitiko; Coccaro, D.M.B.; Vasconcellos, M.B.A.; Marcelli, M.P.

    1999-01-01

    Epiphytic lichens have been used as bioindicators of environmental pollution studies because of their ability to accumulate metals present in the atmosphere at very low concentrations. In this work, experimental conditions for collection and preparation of the lichen samples as well as the experimental procedure for neutron activation analysis were established in order to obtain reliable and useful data for environmental monitoring purposes. Lichen samples were collected from the barks of trees. They were first examined in a stereo microscope, cleaned and then they were washed with water, freeze-dried and ground for analysis. Out of the five species Usnea sp, Parmotrena tinctorum, Canoparmelia caroliniana, Parmotrema sanctiangeli and Canoparmelia texana analysed, the latter was chosen for this work since this species is very abundant on the Brazilian territory except for the coast. The samples and synthetic standards of elements were irradiated at the IEA-R1 nuclear reactor and the concentrations of the elements Al, As, Br, Ca, Cd, Cl, Co, Cr, Cs, Fe, K, lanthanides, Mg, Mn, Na, Rb, Sb, Sc, Se, Th, U, V and Zn were determined by using short and long irradiations. Results obtained in the washed and unwashed lichen samples showed that the cleaning with water can be used in order to eliminate adhering materials. Indeed, most of elements of interest for the environmental contamination accumulated by the lichens were not removed. The study of the influence of the age of the lichen indicated that its elemental concentrations increase with its age or with the length of exposure. Results obtained for lichens collected from four different trees in the same sampling area varied from about 3.4 to 50%. The homogeneity of the sample was checked by analyzing replicates. The precision and the accuracy of the method were evaluated by analyzing IAEA 336 Lichen and NIST 1752 Citrus Leaves. (author)

  10. Variability in In Vitro Macrophage Activation by Commercially Diverse Bulk Echinacea Plant Material is Predominantly Due to Bacterial Lipoproteins and Lipopolysaccharides

    Science.gov (United States)

    We previously reported that the majority of in vitro monocyte/macrophage activation exhibited by extracts of Echinacea and other botanicals depends upon bacterial lipopolysaccharides and Braun-type bacterial lipoproteins. We determined the contribution made by these bacterial components to the overa...

  11. Participation in Leisure Activities among Canadian Children with Arthritis: Results from a National Representative Sample.

    Science.gov (United States)

    Cavallo, Sabrina; Majnemer, Annette; Mazer, Barbara; Chilingaryan, Gevorg; Ehrmann Feldman, Debbie

    2015-06-01

    To describe the level of participation in leisure activities among children and youth with arthritis, as well as to identify the sociodemographic (age, sex, family income), disease-related (functional limitations, disease duration, pain, medication use, child's need for assistance), and contextual factors (use of rehabilitation services, proximity of local recreation facilities, cost of activities) that may be associated. Data from the Participation and Activity Limitation Survey (PALS) 2006, a Canadian postcensus survey, was analyzed. Bivariate and multivariable linear regression analyses were applied to examine the associations between the sample's level of participation in leisure activities, and sociodemographic, disease-related, and contextual characteristics. In Canada in 2006, an estimated 4350 children ranging in age from 5 to 14 years were living with arthritis. Fifty-six percent of parents reported that arthritis restricted their child's participation in leisure activities. Bivariate analysis showed that the availability of local recreational facilities, the affordability of activities, and the child not requiring any assistance were all associated (modified Bonferroni correction α leisure activities. Multiple linear regressions showed that higher family income (β 0.47, 95% CI 0.09, 0.85) and greater perceived pain (β 0.59, 95% CI 0.07, 1.10) were positively associated with involvement in informal leisure. Our findings underline the importance of considering contextual factors in developing treatment plans aimed at improving participation in leisure activities among children with arthritis. Future longitudinal studies targeting children living with arthritis could provide pertinent information on participation over fluctuations in disease status.

  12. Characterization and bulk properties of oxides

    International Nuclear Information System (INIS)

    Sonder, E.; Connolly, T.F.

    1979-06-01

    The bulk properties of oxides are divided into two classes, intrinsic properties which depend solely on the identity of the material, and extrinsic ones, which differ for different samples of the same compound. Sources of tabulated numerical values of intrinsic properties are given and modern developments in information storage and retrieval are discussed. Extrinsic properties are shown to depend on defects and trace impurities in the samples. Techniques of trace impurity analysis are discussed and realistic limits of detection and accuracies are given for routine analyses

  13. Application of the neutron activation analysis method to the multielemental determination of food samples

    International Nuclear Information System (INIS)

    Maihara, V.A.

    1985-01-01

    The thermal neutron activation analysis method was applied to the determination of elements present at low concentrations and trace levels in samples of bread and milk powder using non-destructive analyses were based on gamma ray spectrometric measurements of samples and standards irradiated for periods which varied from some minutes to eight hours in a thermal neutron flux of about 10 12 n cm -2 s -1 . The concentrations obtained for milk powder were compared with the data obtained by other autors from different contries. For the bread, that comparison was not possible, because data about trace analysis in bread samples were not found. Besides, the results obtained for the various brands of bread and milk by means of non destructive and destructive analyses were compared using Student's t criterion. Some basic considerations about 'Detection Limit' were done, mainly in relation to its application in the technique used in the present work. The detection and determination limits of the trace elements analysed by destructive and non destructive techniques in bread and milk powder samples were determined using the Currie and Girardi methods. The precision of the analyses and the results obtained for the detection limits of the analysed trace elements are discussed. (Author) [pt

  14. Measurement of the carbon 14 activity at natural level in air samples

    International Nuclear Information System (INIS)

    Olivier, A.; Tenailleau, L.; Baron, Y.; Maro, D.

    2004-01-01

    The aim of the study was to measure the carbon 14 activity at natural level in air samples using classical methods of radiochemistry and beta counting. Three different methods have been tested in order to minimise the detection limit. In the three methods, the first step consists in trapping the atmospheric carbon 14 into NaOH (1N) using a bubbling chamber. The atmospheric carbon dioxide reacts with NaOH to form Na 2 CO 3 . In the first method the Na 2 CO 3 solution is mixed with a liquid scintillate and is directly analysed by liquid scintillation counting (LSC). The detection limit is approximately 1 Bq/m 3 of air samples. The second method consists in evaporating the carbonate solution and then counting the solid residue with a proportional gas circulation counter. The detection limit obtained is lower than the first method (0.4 Bq/m 3 of air samples). In the third method, Na 2 CO 3 is precipitated into CaCO 3 in presence of CaCl 2 . CaCO 3 is then analysed by LSC. This method appear to be the most appropriate, the detection limit is 0.05 Bq/m 3 of air samples. (author)

  15. Application of the neutron activation analysis method to the multielemental determination of food samples

    International Nuclear Information System (INIS)

    Maihara, V.A.

    1985-01-01

    The application of thermal neutron activation analysis method for determining elements presented at low concentration and level of traces in bread and dried milk samples, using non-destructive and chemical analyses, was studied. The non-destructive analyses were based on measurements of gamma spectrometry of samples and standards irradiated by thermal neutron flux on the order of 10 12 n cm -2 s -1 . The irradiation time varied from some minutes to 8 hours. The Na, Cl, Mn, Br, Fe, Zn, Rb, Sb, Cr and Sc elements in bread samples were determined. The Na, K, Cl, Ca, Mg, Br, Al, Zn, Rb, Sb and Cr elements in dried milk samples were determined. In destructive analysis, the 24 Na radioisotope was separeted by retention on hydrated antimony pentoxide column from 8N HCL after digestion of organic matter. The bread was dissolved in HNO 3 concentrated and 70% of HCLO 4 and the dried milk was dissolved in HNO 3 concentrated and H 2 O 2 . The 64 Cu, 69m Zn and 140 La radioisotopes determined. The concentrations obtained for dried milk were compared with data obtained by other authors from different contries. Basic considerations on detection limit related to its application on the technique used in this work, were done. The detection limits and trace elements using the Currie and Girardi methods were determined. The accuracy of results obtained for trace element detection limits is discussed. (Author) [pt

  16. Magnetizing of permanent magnet using HTS bulk magnet

    International Nuclear Information System (INIS)

    Oka, Tetsuo; Muraya, Tomoki; Kawasaki, Nobutaka; Fukui, Satoshi; Ogawa, Jun; Sato, Takao; Terasawa, Toshihisa

    2011-01-01

    A demagnetized Nd-Fe-B permanent magnet was scanned just above the magnetic pole containing the HTS bulk magnet, generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnetic plates inversely with various overlap distances between the tracks of the HTS bulk magnet. The magnetic field of the 'rewritten' magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated. (author)

  17. Uncertainty Estimation of Neutron Activation Analysis in Zinc Elemental Determination in Food Samples

    International Nuclear Information System (INIS)

    Endah Damastuti; Muhayatun; Diah Dwiana L

    2009-01-01

    Beside to complished the requirements of international standard of ISO/IEC 17025:2005, uncertainty estimation should be done to increase quality and confidence of analysis results and also to establish traceability of the analysis results to SI unit. Neutron activation analysis is a major technique used by Radiometry technique analysis laboratory and is included as scope of accreditation under ISO/IEC 17025:2005, therefore uncertainty estimation of neutron activation analysis is needed to be carried out. Sample and standard preparation as well as, irradiation and measurement using gamma spectrometry were the main activities which could give contribution to uncertainty. The components of uncertainty sources were specifically explained. The result of expanded uncertainty was 4,0 mg/kg with level of confidence 95% (coverage factor=2) and Zn concentration was 25,1 mg/kg. Counting statistic of cuplikan and standard were the major contribution of combined uncertainty. The uncertainty estimation was expected to increase the quality of the analysis results and could be applied further to other kind of samples. (author)

  18. Neutron activation analysis of 127I and 129I environmental samples

    International Nuclear Information System (INIS)

    Takeishi, Minoru; Namiki, Atsushi; Ishida, Junichiro; Iwai, Makoto

    1987-01-01

    The analytical method of 127 I and 129 I in environmental samples has been studied and the background levels of these nuclides in soils, seaweeds and milk were measured. The analytical method consists of the combustion technique and neutron activation analysis (N.A.A.). The iodine was separated from samples by ignition at about 1,000 deg C in a quartz combustion apparatus with an oxygen and a nitrogen stream, and was absorbed by small amounts of active charcoal. The iodine was then purified through the carbontetrachloride extraction method and the PdI 2 decomposition method. Irradiation was conducted by JRR-4 (n th : 8 x 10 13 n/cm 2 · sec) for 40 min. After irradiation, the iodine was purified by the solvent extraction method same as pre-irradiation extraction. Each activity of 126 I and 130 I, which was produced by 127 I(n,2n) 126 I and 129 I(n,γ) 130 I reaction respectively, was measured by γ-spectrometry using a Ge-detector. The lower detection limits of 129 I by this method were 4 x 10 -7 Bq/g for dry soil, 7 x 10 -8 Bq/g for fresh seaweeds and 7 x 10 -6 Bq/l for fresh milk, respectively. The relative standard deviation of 129 I measurements in soil and milk were less than 10 %. (author)

  19. COLOUR, PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF THE SLOVAK ALIBERNET RED WINE SAMPLES

    Directory of Open Access Journals (Sweden)

    Daniel Bajčan

    2015-02-01

    Full Text Available Sixteen Alibernet wine samples, originated from three most important Slovak vineyard regions, were evaluated spectrophotometrically for the content of total polyphenols, content of total anthocyanins, antioxidant activity and wine colour density. The determined total polyphenol contents in observed wines ranged from 2141 to 4274 mg gallic acid per liter (average content was 3057 mg gallic acid/L and total anthocyanin contents ranged from 73.4 to 791.2 mg/L (average content was 403.4 mg/L. Determined values of antioxidant activity were within the interval 54.8 – 86.8% (average value was 74.5% and the values of wine colour density varied between 0.944 and 4.592 (average value was 2.317. The statistical evaluation of the obtained results confirmed only weak linear correlation between total polyphenol content and total anthocyanin content, however strong linear correlations between total anthocyanin content and antioxidant activity, resp. wine colour density were observed. Our results also confirmed very highly significant linear relationship between wine colour density and total polyphenol content, resp. antioxidant activity and between antioxidant activity and total phenolic content.

  20. Application of activated carbon fiber to a filter used for airborne radioiodine sampling

    International Nuclear Information System (INIS)

    Kato, Shohei; Murata, Mikio; Yoshikazu, Yoshida

    1988-01-01

    An airborne radioiodine sampling filter is required to have low pressure drop, mechanical strength enough to a practical use and high collection efficiency under high relative humidity(RH). To develop a filter to meet the requirements, the influences of impregnation amount of triethylenediamin(TEDA) on the collection efficiencies for methyl iodide and the reaction rates were investigated for several kinds of activated carbon fiber varied in specific surface area, pore diameter, etc. Silver silica gel(Sut Chemi, AC6120), silver zeolite(CTI Nuc., AgX Type III), silver alumina(Hitachi Co.) and granular activated charcoal were also examined for comparison. A new type filter made of activated carbon fiber (ACF filter) was developed based on the above experimental results. The ACF filter was examined for the pressure drop by the filter and collection efficiency for methyl iodide being compared with other types of filters such as an activated charcoal cartridge (ACC) and an activated charcoal filter paper (ACP)

  1. Elemental analysis and plant samples at el-Manzala lake by neutron activation analysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Eissa, E A; Rofail, N B; Abdel-Haleem, A S; El-Abbady, W H; Hassan, A M [Arab Republic of Egypt, Atomic energy Authority, Reactor and Neutron Physiscs Department, Cairo (Egypt)

    1996-12-31

    A soil and a plant samples were taken from two locations, Bahr el-Bakar and Bahr Kados at the Manzala lake, where a high pollution is expected. The samples were especially treated and prepared for investigation by thermal neutron activation analysis (NAA). The irradiation facilities of the first egyptian research reactor (ET-R R-1) and the hyper pure germanium (HPGe) detection system were used for such a type of analysis. Among the 34 identified elements Fe, Co, As, Ru, Cd, Te, La, Sm, Eu, Tb, Hg, Th, and U are of a special significance because of their toxic deleterious impact to organisms. This work is a part of a research project concerning pollution studies on the river nile and some lakes of egypt. The data obtained in the present work stand as a reference basic record for any future follow up of the contamination level. 1 tab.

  2. Trace determination of uranium and thorium in biological samples by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Benedik, Ljudmila; Repinc, Urska; Byrne, Anthony R.; Stegnar, Peter

    2002-01-01

    Radiochemical neutron activation analysis (RNAA) is an excellent method for determining uranium and thorium; it offers unique possibilities for their ultratrace analysis using selective radiochemical separations. Regarding the favourably sensitive nuclear characteristics of uranium and of thorium with respect to RNAA, but the different half-lives of their induced nuclides, two different approaches were used. In the first approach uranium and thorium were determined separately via 239 U, 239 Np and 233 Pa. In the second approach these elements were 239 239 233 determined simultaneously in a single sample using U and/or Np and Pa. Isolation of induced nuclides was based on separation by extraction and/or anion exchange chromatography. Chemical yields were measured in each sample aliquot using added 235 U, 238 Np and 231 Pa radioisotopic tracers. (author)

  3. Investigation of Hg volatile losses from samples and standards during neutron activation analysis

    International Nuclear Information System (INIS)

    Dubinskaya, N.; Dundua, V.; Chikhladze, N.

    1979-01-01

    The losses of Hg from phenol formaldehyde resin - bound standards and hair samples in neutron activation analysis in case of their irradiation in the water filled nuclear reactor channel is studied. The mean losses of Hg during 20-30 hrs irradiation at (2-3)x10 18 n/cm 2 are 15-20% with their stopping at double Al-covers. The mean losses of Hg from standards at 200, 250 and 300 deg C are 30, 61 and 86% respectively and do not occur at 150 deg C after their 5 hour heating. The losses of Hg from hair samples packed in polyethylene tubes through the package walls in experimental conditions are not observed

  4. Elemental analysis and plant samples at el-Manzala lake by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Eissa, E.A.; Rofail, N.B.; Abdel-Haleem, A.S.; El-Abbady, W.H.; Hassan, A.M.

    1995-01-01

    A soil and a plant samples were taken from two locations, Bahr el-Bakar and Bahr Kados at the Manzala lake, where a high pollution is expected. The samples were especially treated and prepared for investigation by thermal neutron activation analysis (NAA). The irradiation facilities of the first egyptian research reactor (ET-R R-1) and the hyper pure germanium (HPGe) detection system were used for such a type of analysis. Among the 34 identified elements Fe, Co, As, Ru, Cd, Te, La, Sm, Eu, Tb, Hg, Th, and U are of a special significance because of their toxic deleterious impact to organisms. This work is a part of a research project concerning pollution studies on the river nile and some lakes of egypt. The data obtained in the present work stand as a reference basic record for any future follow up of the contamination level. 1 tab

  5. Physical Activity and Personality Development over Twenty Years: Evidence from Three Longitudinal Samples.

    Science.gov (United States)

    Stephan, Yannick; Sutin, Angelina R; Luchetti, Martina; Bosselut, Grégoire; Terracciano, Antonio

    2018-04-01

    A physically inactive lifestyle is associated with maladaptive patterns of personality development over relatively short follow-up periods. The present study extends existing research by examining whether this association persists over 20 years. Participants (total N = 8,723) were drawn from the Wisconsin Longitudinal Study Graduates and Siblings samples and the Midlife in the United States Study. Controlling for demographic factors and disease burden, baseline physical inactivity was related to steeper declines in conscientiousness in all three samples and a meta-analysis (β=-.06). The meta-analysis further showed that lower physical activity was associated with declines in openness (β=-.05), extraversion (β=-.03), and agreeableness (β=-.03). These findings provide evidence that a physically inactive lifestyle is associated with long-term detrimental personality trajectories.

  6. Microbial activity in subsurface samples before and during nitrate-enhanced bioremediation

    International Nuclear Information System (INIS)

    Thomas, J.M.; Gordy, V.R.; Bruce, C.L.; Ward, C.H.; Hutchins, S.R.; Sinclair, J.L.

    1995-01-01

    A study was conducted to determine the microbial activity at a site contaminated with JP-4 jet fuel before and during nitrate-enhanced bioremediation. Samples at three depths from six different locations were collected aseptically under anaerobic conditions before and during treatment. Cores were located in or close to the source of contamination, downgradient of the source, or outside the zone of contamination. Parameters for microbial characterization included (1) viable counts of aerobic heterotrophic, JP-4 degrading, and oligotrophic bacteria; (2) the most probable number (MPN) of aerobic and anaerobic protozoa; (3) the MPN of total denitrifiers; and (4) the MPN of denitrifiers in hydrocarbon-amended microcosms. The results indicate that the total number of denitrifiers increased by an order of magnitude during nitrate-enhanced bioremediation in most samples. The number of total heterotrophs and JP-4-degrading microorganisms growing aerobically also increased. In addition, the first anaerobic protozoa associated with hydrocarbon-contaminated subsurface materials were detected

  7. Determination of Mineral Contents in Unpolished Rice and Bean Samples by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Moon, J. H.; Kim, S. H.; Baek, S. Y.; Chung, Y. S.

    2012-01-01

    As scientists have focused their researches on the health impacts caused by mineral nutrient deficiencies and hazardous elements, public concern regarding mineral intake from dietary food is rising. In this reason, the dietary habits of Koreans have been shifted from white rice to more nutrient rice like unpolished rice and rice mixed with beans. It is known that unpolished rice and beans contain more protein, vitamin and mineral contents than white rice and are more beneficial to human health, even though they sometimes cause indigestion or allergy. The objectives of this study were to determine the mineral contents in unpolished rice and bean samples by a neutron activation analysis (NAA) and to compare the level of mineral contents between the samples

  8. SHARDA - a program for sample heat, activity, reactivity and dose analysis

    International Nuclear Information System (INIS)

    Shukla, V.K.; Bajpai, Anil

    1985-01-01

    A computer program SHARDA (Sample Heat, Activity, Reactivity and Dose Analysis) has been developed for safety evaluation of Pile Irradiation Request (PIR) for various nonfissile materials in the research reactor CIRUS. The code can also be used, with minor modifications, for PIR safety evaluations for the research reactor DHRUVA, now being commissioned. Most of the data needed for such analysis like isotopic abundances, their various nuclear cross-sections, gamma radiation and shielding data have been built in the code for all nonfissile naturally occuring elements. The PIR safety evaluations can be readily carried out using this code for any sample in elemental, compound or mixture form irradiated in any location of the reactor. This report describes the calculational model and the input/output details of the code. Some earlier irradiations carried out in CIRUS have been analysed using this code and the results have been compared with available operational measurements. (author)

  9. Physical Activity and Personality Development over Twenty Years: Evidence from Three Longitudinal Samples

    Science.gov (United States)

    Stephan, Yannick; Sutin, Angelina R.; Luchetti, Martina; Bosselut, Grégoire; Terracciano, Antonio

    2018-01-01

    A physically inactive lifestyle is associated with maladaptive patterns of personality development over relatively short follow-up periods. The present study extends existing research by examining whether this association persists over 20 years. Participants (total N = 8,723) were drawn from the Wisconsin Longitudinal Study Graduates and Siblings samples and the Midlife in the United States Study. Controlling for demographic factors and disease burden, baseline physical inactivity was related to steeper declines in conscientiousness in all three samples and a meta-analysis (β=−.06). The meta-analysis further showed that lower physical activity was associated with declines in openness (β=−.05), extraversion (β=−.03), and agreeableness (β=−.03). These findings provide evidence that a physically inactive lifestyle is associated with long-term detrimental personality trajectories. PMID:29651189

  10. Collection of size fractionated particulate matter sample for neutron activation analysis in Japan

    International Nuclear Information System (INIS)

    Otoshi, Tsunehiko; Nakamatsu, Hiroaki; Oura, Yasuji; Ebihara, Mitsuru

    2004-01-01

    According to the decision of the 2001 Workshop on Utilization of Research Reactor (Neutron Activation Analysis (NAA) Section), size fractionated particulate matter collection for NAA was started from 2002 at two sites in Japan. The two monitoring sites, ''Tokyo'' and ''Sakata'', were classified into ''urban'' and ''rural''. In each site, two size fractions, namely PM 2-10 '' and PM 2 '' particles (aerodynamic particle size between 2 to 10 micrometer and less than 2 micrometer, respectively) were collected every month on polycarbonate membrane filters. Average concentrations of PM 10 (sum of PM 2-10 and PM 2 samples) during the common sampling period of August to November 2002 in each site were 0.031mg/m 3 in Tokyo, and 0.022mg/m 3 in Sakata. (author)

  11. Neutron activation analysis of neonate and maternal hair sampled in areas with different levels of pollution

    International Nuclear Information System (INIS)

    Obrusnik, I.; Skrivanek, O.; Umlaufova, M.; Hovorka, V.

    1985-01-01

    Instrumental neutron activation analysis was performed on human head hair of newborns and mothers sampled in two areas with different levels of environmental exposure. The group of neonates from the exposed area (polluted by thermal power plants burning brown coal and by chemical industry) exhibited higher levels of several trace elements in hair, e.g. Se, Zn, Hg and Sb in comparison with the control group. Moreover, the mean concentrations of Se, Hg, Zn and Br in neonate hair were found to be higher than in mothers' hair. Although the study revealed statistically significant differences in the composition of neonate hair samples in areas with different levels of environmental exposure, the differences are relatively small. Only a thorough long-term study both with environmental and medical observations can prove a direct connection of the elevated levels of some trace elements in neonate hair with the higher incidence of mental diseaes of children living in the exposed area. (author)

  12. Isotope identification of Saudi Arabian rock samples from Umm Al-Birak using neutron activation analysis

    International Nuclear Information System (INIS)

    Kahtani, S.A.

    1984-12-01

    Forty eight geological samples from Umm Al-Birak area in the northwest part of Saudi Arabia are analyzed qualitatively and quantitatively using the instrumental neutron activation analysis technique. Samples are properly prepared and irridiated in the reactor facilities of the National Tsing-Hue University in Taiwan. Gamma spectra from high resolution detector are analyzed using BRUTAL code. Final calculations are made by two independent programs, namely, ELCAL and SMPCL. Twenty trace elements are identified and their concentrations are used in the investigation of the geochemistry of the Umm Al-Birak microgranite site. These elements are: Co, Cr, Eu, Fe, Hf, K, La, Lu, Na, Rb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr. It is shown that high grade area is a differentiated rock that crystallized in a late stage of Umm Al-Birak microgranite area. 43 Ref

  13. Determination of Mineral Contents in Unpolished Rice and Bean Samples by Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moon, J. H.; Kim, S. H.; Baek, S. Y.; Chung, Y. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    As scientists have focused their researches on the health impacts caused by mineral nutrient deficiencies and hazardous elements, public concern regarding mineral intake from dietary food is rising. In this reason, the dietary habits of Koreans have been shifted from white rice to more nutrient rice like unpolished rice and rice mixed with beans. It is known that unpolished rice and beans contain more protein, vitamin and mineral contents than white rice and are more beneficial to human health, even though they sometimes cause indigestion or allergy. The objectives of this study were to determine the mineral contents in unpolished rice and bean samples by a neutron activation analysis (NAA) and to compare the level of mineral contents between the samples

  14. G-protein activity in Percoll-purified plasma membranes, bulk plasma membranes, and low-density plasma membranes isolated from rat cerebral cortex

    Czech Academy of Sciences Publication Activity Database

    Bouřová, Lenka; Stöhr, Jiří; Lisý, Václav; Rudajev, Vladimír; Novotný, Jiří; Svoboda, Petr

    2009-01-01

    Roč. 15, č. 4 (2009), BR111-BR122 ISSN 1234-1010 R&D Projects: GA MŠk(CZ) LC554; GA MŠk(CZ) LC06063; GA ČR(CZ) GA309/06/0121; GA AV ČR(CZ) IAA500110606 Institutional research plan: CEZ:AV0Z50110509 Keywords : rat cerebral cortex * plasma membrane * G-protein activity Subject RIV: CE - Biochemistry Impact factor: 1.543, year: 2009

  15. Application of neutron activation analysis to trace element determinations in lung samples

    International Nuclear Information System (INIS)

    Rocero, Sizue Ota

    1992-01-01

    The purpose of this work was to apply the instrumental neutron activation analysis method to determine trace elements in lung samples from smokers and non smokers. Samples of lung tissues and lymph nodes from pulmonary hilum analyzed were collected from autopsies by researchers from the Medicine College of the University of Sao Paulo, SP, Brazil. Adequate conditions for preparation and analysis of samples were previously established. The preparation of samples consisted of homogenization, lyophilization and sterilization in 60 Co source. The samples and standards were irradiated in the IEA-R1 reactor under thermal neutron flux of 3.7 x 10 11 n.cm -2 .s -1 for 30 min to determine Cl, K, Mn and Na and for 16 h under flux of 10 19 n.cm -2 .s -1 for the determination of Au, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Rb, Sb, Sc, Se, Th and Zn. The counting were carried out with a hiperpure (ge) detector connected to a 4096 channels analyzer and a microcomputer. the results obtained for lung sample analyses indicated a good reproducibility of the method for most of the elements determined with relative standard deviations lower than 10.5%. The accuracy of the method was evaluated by analyzing reference materials such as IAEA Animal Muscle H-4, NIST Bovine Liver 1577a, IUPAC Bowen's Kale and NIES Vehicle Exhaust Particulates. The results obtained from these analyzes agreed with the values of the literature for several elements with relative errors less than 20%. Less precise and accurate results were obtained for elements with concentrations at the Mup/Kg levels. Elemental concentrations obtained in the lung tissue analyses were within the range of reference values for normal subjects presented in the literature, except for the Cl concentrations for non smokers, Hf in both groups and Sb for the smokers. By comparing results obtained for lung samples from smokers and non smokers, the concentrations of Ce, Cr and Sb were higher in lungs from smokers and the others elements were

  16. Effect of annealing ambience on the formation of surface/bulk oxygen vacancies in TiO2 for photocatalytic hydrogen evolution

    Science.gov (United States)

    Hou, Lili; Zhang, Min; Guan, Zhongjie; Li, Qiuye; Yang, Jianjun

    2018-01-01

    The surface and bulk oxygen vacancy have a prominent effect on the photocatalytic performance of TiO2. In this study, TiO2 possessing different types and concentration of oxygen vacancies were prepared by annealing nanotube titanic acid (NTA) at various temperatures in air or vacuum atmosphere. TiO2 with the unitary bulk single-electron-trapped oxygen vacancies (SETOVs) formed when NTA were calcined in air. Whereas, TiO2 with both bulk and surface oxygen vacancies were obtained when NTA were annealed in vacuum. The series of TiO2 with different oxygen vacancies were systematically characterized by TEM, XRD, PL, XPS, ESR, and TGA. The PL and ESR analysis verified that surface oxygen vacancies and more bulk oxygen vacancies could form in vacuum atmosphere. Surface oxygen vacancies can trap electron and hinder the recombination of photo-generated charges, while bulk SETOVs act as the recombination center. The surface or bulk oxygen vacancies attributed different roles on the photo-absorbance and activity, leading that the sample of NTA-A400 displayed higher hydrogen evolution rate under UV light, whereas NTA-V400 displayed higher hydrogen evolution rate under visible light because bulk SETOVs can improve visible light absorption because sub-band formed by bulk SETOVs prompted the secondary transition of electron excited.

  17. Nonlinear AC susceptibility, surface and bulk shielding

    Science.gov (United States)

    van der Beek, C. J.; Indenbom, M. V.; D'Anna, G.; Benoit, W.

    1996-02-01

    We calculate the nonlinear AC response of a thin superconducting strip in perpendicular field, shielded by an edge current due to the geometrical barrier. A comparison with the results for infinite samples in parallel field, screened by a surface barrier, and with those for screening by a bulk current in the critical state, shows that the AC response due to a barrier has general features that are independent of geometry, and that are significantly different from those for screening by a bulk current in the critical state. By consequence, the nonlinear (global) AC susceptibility can be used to determine the origin of magnetic irreversibility. A comparison with experiments on a Bi 2Sr 2CaCu 2O 8+δ crystal shows that in this material, the low-frequency AC screening at high temperature is mainly due to the screening by an edge current, and that this is the unique source of the nonlinear magnetic response at temperatures above 40 K.

  18. Rare earths analysis of rock samples by instrumental neutron activation analysis, internal standard method

    International Nuclear Information System (INIS)

    Silachyov, I.

    2016-01-01

    The application of instrumental neutron activation analysis for the determination of long-lived rare earth elements (REE) in rock samples is considered in this work. Two different methods are statistically compared: the well established external standard method carried out using standard reference materials, and the internal standard method (ISM), using Fe, determined through X-ray fluorescence analysis, as an element-comparator. The ISM proved to be the more precise method for a wide range of REE contents and can be recommended for routine practice. (author)

  19. Determination of phosphorus in wheat grass samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Kulkarni, S.D.; Rajurkar, N.S.; Acharya, R.; Nair, A.G.C.; Reddy, A.V.R.

    2005-01-01

    An instrumental neutron activation analysis (INAA) method using β-counting was used to determine phosphorus in wheat grass; grown in three different conditions. The phosphorus concentration was found to be in the range of 950-23000 mg/g in the samples grown in different conditions. The accuracy of the method was evaluated by determining phosphorus in three reference materials and the % deviations were within 10%. Reliability of the method was checked by following the half-life of the 32 P. (author)

  20. Neutron activation analysis of chemical impurities in manipulated samples of omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Sepe, Fernanda Peixoto; Leal, Alexandre Soares; Gomes, Tatiana Cristina Bomfim; Menezes, Maria Angela de Barros Correia; Silva, Maria Aparecida, E-mail: asleal@cdtn.br [Nuclear Technology Development Centre/Brazilian Commission for Nuclear Energy (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    In this work, samples of Omeprazole (C{sub 17}H{sub 19}N{sub 3}O{sub 3}S), a largely used drug in the treatment of dyspepsia and peptic ulcer, were acquired from five different pharmacies of manipulation - or retail pharmacies which prepare personalized drugs under medical recommendation - in Belo Horizonte/Brazil and investigated using the k{sub 0} - Neutron Activation Analysis (NAA). The preliminary results showed the presence of elements not foreseen in the original formula. It confirms the potential risk offered by medicines without suitable inspection. (author)

  1. Investigation of an egyptian phosphate ore sample by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Eissa, E.A.; Aly, R.A.; Rofail, N.B.; Hassan, A.M.

    1995-01-01

    A domestic phosphate ore sample has been analysed by means of prompt and delayed gamma-ray spectrometry following the activation by thermal neutron capture technique. The rabbit pneumatic transfer system (RPTS), long irradiation facility and two Pu/Be (2,5 Ci each) neutron sources set-Pu for prompt (n,gamma) were applied. The high purity germanium (HPGe) gamma-ray spectrometer with a personal computer analyzer (PCA) system were used for spectrum measurements. Programmes on the VAX computer were utilized for estimating the elemental concentrations of 22 out of 36 elements identified in this work. 2 tabs

  2. Neutron activation analysis of chemical impurities in manipulated samples of omeprazole

    International Nuclear Information System (INIS)

    Sepe, Fernanda Peixoto; Leal, Alexandre Soares; Gomes, Tatiana Cristina Bomfim; Menezes, Maria Angela de Barros Correia; Silva, Maria Aparecida

    2011-01-01

    In this work, samples of Omeprazole (C 17 H 19 N 3 O 3 S), a largely used drug in the treatment of dyspepsia and peptic ulcer, were acquired from five different pharmacies of manipulation - or retail pharmacies which prepare personalized drugs under medical recommendation - in Belo Horizonte/Brazil and investigated using the k 0 - Neutron Activation Analysis (NAA). The preliminary results showed the presence of elements not foreseen in the original formula. It confirms the potential risk offered by medicines without suitable inspection. (author)

  3. Analytical laboratory quality assurance guidance in support of EM environmental sampling and analysis activities

    International Nuclear Information System (INIS)

    1994-05-01

    This document introduces QA guidance pertaining to design and implementation of laboratory procedures and processes for collecting DOE Environmental Restoration and Waste Management (EM) ESAA (environmental sampling and analysis activities) data. It addresses several goals: identifying key laboratory issues and program elements to EM HQ and field office managers; providing non-prescriptive guidance; and introducing environmental data collection program elements for EM-263 assessment documents and programs. The guidance describes the implementation of laboratory QA elements within a functional QA program (development of the QA program and data quality objectives are not covered here)

  4. Determination of total alpha activity index in samples of radioactive wastes

    International Nuclear Information System (INIS)

    Galicia C, F. J.

    2015-01-01

    This study aimed to develop a methodology of preparation and quantification of samples containing radionuclides beta and/or alpha emitters, to determine the rates of alpha and beta total activity of radioactive waste samples. For this, a device of planchettes preparer was designed, to assist the planchettes preparation in a controlled environment and free of corrosive vapors. Planchettes were prepared in three means: nitrate, carbonate and sulfate, to different mass thickness, natural uranium (alpha and beta emitter) and in case of Sr-90 (beta emitter pure) only in half nitrate; and these planchettes were quantified in an alpha/beta counter, in order to construct the self-absorption curves for alpha and beta particles. These curves are necessary to determine the rate of alpha-beta activity of any sample because they provide the self-absorption correction factor to be applied in calculating the index. Samples with U were prepared with the help of the device of planchettes preparer and subsequently were analyzed in the proportional counter Mpc-100 Pic brand. Samples with Sr-90 were prepared without the device to see if there was a different behavior with respect to obtaining mass thickness. Similarly they were calcined and carried out count in the Mpc-100. To perform the count, first the parameters of counter operating were determined: operating voltages for alpha and beta particles 630 and 1500 V respectively, a count routine was generated where the time and count type were adjusted, and counting efficiencies for alpha and beta particles, with the aid of calibration sources of 210 Po for alphas and 90 Sr for betas. According to the results, the counts per minute will decrease as increasing the mass thickness of the sample (self-absorption curve), adjusting this behavior to an exponential function in all cases studied. The minor self-absorption of alpha and beta particles in the case of U was obtained in sulfate medium. The self-absorption curves of Sr-90 follow the

  5. Active Collection of Land Cover Sample Data from Geo-Tagged Web Texts

    Directory of Open Access Journals (Sweden)

    Dongyang Hou

    2015-05-01

    Full Text Available Sample data plays an important role in land cover (LC map validation. Traditionally, they are collected through field survey or image interpretation, either of which is costly, labor-intensive and time-consuming. In recent years, massive geo-tagged texts are emerging on the web and they contain valuable information for LC map validation. However, this kind of special textual data has seldom been analyzed and used for supporting LC map validation. This paper examines the potential of geo-tagged web texts as a new cost-free sample data source to assist LC map validation and proposes an active data collection approach. The proposed approach uses a customized deep web crawler to search for geo-tagged web texts based on land cover-related keywords and string-based rules matching. A data transformation based on buffer analysis is then performed to convert the collected web texts into LC sample data. Using three provinces and three municipalities directly under the Central Government in China as study areas, geo-tagged web texts were collected to validate artificial surface class of China’s 30-meter global land cover datasets (GlobeLand30-2010. A total of 6283 geo-tagged web texts were collected at a speed of 0.58 texts per second. The collected texts about built-up areas were transformed into sample data. User’s accuracy of 82.2% was achieved, which is close to that derived from formal expert validation. The preliminary results show that geo-tagged web texts are valuable ancillary data for LC map validation and the proposed approach can improve the efficiency of sample data collection.

  6. Application of neutron activation analysis technique in elemental determination of lichen samples

    International Nuclear Information System (INIS)

    Djoko Prakoso Dwi Atmodjo; Syukria Kurniawati; Woro Yatu Niken Syahfitri; Nana Suherman; Dadang Supriatna

    2010-01-01

    Lichen is one of the biological materials as pollution monitor that can give information about level, direction, and history of various pollutants in environment. Small sample weights and elemental content of lichens is on the order of ppm, so that its characterization requires advanced analytical techniques that has high sensitivity and capable of analyzing samples with weight of - 25 mg, such as neutron activation analysis. In this research, determination of elements was done in lichen samples obtained from Kiaracondong and Holis areas in Bandung city, to understanding the difference of industrial exposure level on surrounding environment. Samples were irradiated in RSG GA Siwabessy, Serpong, at 15 MW for 1-2 and 60 minutes for short irradiation and long irradiation, respectively. The samples were then counted using HPGe detector with GENIE 2000 software. The level of element in lichen for Kiaracondong area were Co, Cr, Cs, Fe, Mg, Mn, Sb, Sc, and V in the range of 0.55-0.86, 1.47-2.57, 0.87-1.19, 540-1005, 949-1674, 34.91-45.94, 0.08-0.14, 0.16-0.31, and ≤ 2.33 mg/kg, respectively, while for Holis area were 1.04-2.37, 4.41-10.36, 0.41-0.89, 3166-709, 1131-1422, 40.97-72.51, 0.33-0.50, 0.98-2.18, and 5.30-13.05 mg/kg respectively. From these results, it is known that pollution exposure from the semi industrial area Holis provide greater influence than in the semi industrial area Kiaracondong. (author)

  7. Determination of trace elements in lichen samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Saiki, Mitiko; Horimoto, Lidia K.; Vasconcellos, Marina B.A.; Marcelli, Marcelo P.; Sumita, Nairo M.; Saldiva, Paulo H.N.

    2001-01-01

    Samples of Canoparmelia texana lichen collected in different sites of Sao Paulo and Parana States, Brazil, were analysed by neutron activation analysis in order to obtain preliminary information on the air quality in these regions and also to select a region of interest for biomonitoring studies. Also Tadescantia pallida plant has been analysed in order to study the viability of using this specimen in environmental pollution monitoring. Lichens samples were collected from tree barks which were also collected to investigate the contribution of substrate derived elements to elements present in lichens. Young and old leaves of T. pallida were collected separately in order to study the leaf age effects on their elemental levels. The samples were cleaned, washed with distilled water, dried and ground for the analyses. Samples and standards were irradiated at the IEA-Rlm nuclear reactor for short and long periods and concentrations of the elements Al, As, Ca, Cd, Cl, Co, Cr, Cs, Fe, Hf, Mg, Mn, Rb, Sb, Sc, D, Th, U, V Zn and lanthanides were determined. Preliminary results obtained for T. texana lichen indicated that three sites (Ibiuna, Botanical Garden and Parque de Vila Velha) present low concentrations of the most elements analysed. Therefore lichens from these regions could be analysed to establish baseline levels of elements for monitoring purposes. Samples collected in open areas presented high concentrations of some elements probably due to the accumulation of elements originating from soil and from heavy vehicular traffic. Elemental concentrations obtained in outer barks were similar or smaller than those results obtained for lichens. Results obtained for T. pallida indicated that concentrations of elements in old leaves of this plant are of the same magnitude or slightly higher than those presented in young ones. (author)

  8. Study on the determination of palladium in biological samples by the method of neutron activation analysis

    International Nuclear Information System (INIS)

    Cavalcante, Cassio Queiroz

    2007-01-01

    Palladium is one of platinum group elements present in the nature at very low concentrations. However with the use of this element in the automobile catalyzers Pd became a new pollutant. Besides, Pd has been studied in the preparation of new antitumour drugs. Consequently, there is a need to determine Pd concentrations in biological and environmental samples. This study presents palladium results obtained in the analysis of biological samples and reference materials using instrumental thermal and epithermal neutron activation analysis (INAA and ENAA). The solvent extraction and solid phase extraction separation methods were also applied before ENAA. The samples analyzed in this study were, reference material BCR 723 - Palladium, Platinum and Rhodium in road dust, CCQM-P63 automotive catalyst material of the Proficiency Test and bovine tissue samples containing palladium prepared in the laboratory. Samples and palladium synthetic standard were irradiated at the IEA-R1 nuclear research reactor under thermal neutron flux of about 4 x 10 12 n cm-2 s-1, during a period of 4 and 16 h for INAA and ENAA, respectively. The induced gamma activity of 109 Pd to the sample and standard was measured using a hyper pure Ge detector coupled to a gamma ray spectrometer. The palladium concentration was calculated by comparative method. The gamma ray energy of 109 Pd radioisotope measured was of 88.0 keV, located in a spectrum region of low energy where occurs the interference of X rays, 'Bremsstrahlung' radiations, as well as Compton effect of 24 Na. The pre-separation of palladium from interfering elements by solvent extraction was performed using dimethylglyoxime complexant and chloroform as diluent. In the case of the pre separation procedure using solid reversed phase column, the palladium was retained using N,N-diethyl-N'-benzoyl thiourea complexant and eluted using ethanol. Aliquots of the resulting solutions from the pre-separations, free of interfering elements, were

  9. The concentration of active and inactive strontium in some Danube river samples

    International Nuclear Information System (INIS)

    Koshutich, K.; Lulich, S.

    1985-01-01

    The following fish species were investigated: Barbus barbus, Acipencer ruthenus, Abramis brama, Stizostedion lucioperca, Silurus glanis, Cyprinus caprio. The samples were collected during 1981. The inactive strontium in the water residue (after evaporation), sediment and fishes ewrw determined by nondestructive neutron activation analysis by using gamma couting system consisted of a 40 cm 3 Ge(Li) semiconductor rystal attached to a 4096-channel pulsehight analyser. The standard solution contained 5x10 -5 g of strontium per 100 lambda. Radioactive strontium was measured after several separation procedures. 90 SrCO 3 in equilibrium with its daughter 90 Y was detected in the β-low-level counting anticoincident system with gas-flow detector. The results confirmed the literature data that the sediment concentrations of the total strontium and the active 90 Sr are several times greater than those in water

  10. Investigating the origins of double photopeaks in CsI:Tl samples through activator mapping

    Science.gov (United States)

    Onken, Drew R.; Gridin, Sergii; Williams, Richard T.; Williams, Charles B.; Donati, George L.; Gayshan, Vadim; Vasyukov, Sergey; Gektin, Alex

    2018-06-01

    Careful examination of the origins of double photopeaks in CsI:Tl provides a foundation for exploring the relationship between activator homogeneity and photopeak resolution in scintillators. In rare cases, certain CsI:Tl crystals exhibit a second photopeak in the pulse-height spectrum. A combination of optical mapping and ICP-MS measurements reveals the presence of two distinct regions with differing Tl concentrations in these crystals. The oscillator strength of the 299 nm absorption A-band of Tl in CsI was measured to be 0.0526 ± 0.0008; this parameter can be used to quantify activator concentration from the optical absorption. Using published measurements of luminescence intensity versus Tl concentration, the distributions of Tl measured from optical absorption maps of the samples were reconstructed into photopeaks in good agreement with experiment. The distribution of Tl concentrations in these particular crystals allowed examining luminescence pulse shape as a function of Tl concentration.

  11. Determination of phosphorus and calcium in biological samples by activation with 14 MeV neutrons

    International Nuclear Information System (INIS)

    Berretta, Jose Roberto

    1995-01-01

    Analytical methods for phosphorus and calcium in biological samples by means of activation with 14 MeV neutrons, using the Van de Graaff accelerator from the Instituto de Pesquisas Energeticas e Nucleares, SP, Brazil are developed. For phosphorus analysis, powder samples were pressed into pellets, weighed and transferred to polyethylene plastic envelopes. The pellets with cadmium shielding were irradiated under a fast neutron flux for 5 to 10 minutes, and further counted in a HPGe detector for 5 minutes. Calcium analysis was performed by cyclic irradiation. Samples were irradiated for 10 minutes. After a decay time of 2 minutes, gamma counting was performed for 10 minutes. After a decay time of 2 minutes, a new irradiation ws made. The irradiation cycle was repeated 5 times and the counting spectrum obtained in each cycle was accumulated in the multi channel analyser. The variation of the neutron flux was followed by using a BF 3 detector calibrated with and aluminium monitor. By means of the gamma spectrum and the neutron counting of the BF 3 detector it was possible to estimate phosphorus and calcium concentrations in the sample analyzed. The methods were checked in the reference samples from the International Atomic Energy Agency and in commercial samples of powder milk, fertilizer and animal bone. Phosphorus contents in bone (A3/74) and milk (A-11) reference materials were (15.6 +- 1.8%) and (0.9 +- 0.1)%, respectively. These values are in good agreement to the certified values (15.5 +- 0.5)% and (0.910 +- 0.102)%, respectively. Calcium analysis carried out in bone (A3/74) presented a value of (31.8+-4.1)% and the certified value was of (31.3 +- 0.3)%. Detection limits for phosphorus and calcium were determined in different analyzed samples. The agreement of the results obtained with the certified values confirmed the suitability of the methods for phosphorus and calcium analysis. The methods are fast and laborious chemical procedures are not required. (author)

  12. The Relationship between Active Coping and Trait Resilience across U.S. and Taiwanese College Student Samples

    Science.gov (United States)

    Li, Ming-Hui; Nishikawa, Takeshi

    2012-01-01

    This study compared predictors of active coping (people's tendency to actively cope with stress) among college students in the United States and Taiwan. In both samples, trait resilience predicted active coping and mediated the effect of self-efficacy on active coping. The findings indicate that trait resilience influences college students' active…

  13. Suitability of the cellular viability technique as a control tool of the chlorine dosage on the activated sludge of a biological process affected by bulking

    International Nuclear Information System (INIS)

    Montaya Martinez, T.; Zornoza Zornoza, A.; Granell Munoz, P.; Fayos, G.; Fajarddo, V.; Zorrilla, F.; Alonso Molina, J. L.; Morenilla Martinez, J. J.; Bernacer Bonora, I.; Martinez Francisco, F. J.

    2009-01-01

    This work demonstrates the suitability of the cellular viability technique as a control tool of the chlorine dosage on the activated sludge of a biological process affected by the overabundance of the filamentous bacteria (Thiothrix-021N). This technique was used to establish the chlorine dosage according to the observed damages on cellular membranes of both, floc-forming bacteria as well as filamentous bacteria. To identify the filamentous bacteria responsible for the macro-structural alteration of the flocs, several criteria were, met, including morphologic characteristics as well as conventional microbiological stains: Gram, Neisser and polyhydroxy alkanoates. FISH was used to confirm the obtained results, providing a definitive identification of the filamentous bacteria responsible for the alteration. (Author) 11 refs

  14. Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: Batch and column studies

    KAUST Repository

    Maeng, Sungkyu; Sharma, Saroj K.; Abel, Chol D T; Magic-Knezev, Aleksandra; Amy, Gary L.

    2011-01-01

    Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log K ow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation

  15. Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: Batch and column studies

    KAUST Repository

    Maeng, Sungkyu

    2011-10-01

    Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log K ow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation

  16. Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: batch and column studies.

    Science.gov (United States)

    Maeng, Sung Kyu; Sharma, Saroj K; Abel, Chol D T; Magic-Knezev, Aleksandra; Amy, Gary L

    2011-10-15

    Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log Kow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation

  17. Neutron activation determination of iridium, gold, platinum, and silver in geologic samples

    International Nuclear Information System (INIS)

    Millard, H.T.

    1986-01-01

    Low-level methods for the determination of iridium and other noble metals have been important in recent years due to interest in locating abundance anomalies associated with the Cretaceous/Tertiary (K/T) boundary. Typical iridium anomalies are in the range of 1 to 100 ppb. Thus methods with detection limits near 0.1 ppb should be adequate to detect K/T boundary anomalies. Radiochemical neutron activation analysis methods continue to be required although instrumental neutron activation analysis techniques employing elaborate gamma-counters are under development. In the procedure employed in this study samples irradiated in the epithermal neutron facility of the U.S. Geological Survey TRIGA Reactor are treated with a mini-fire assay technique. The iridium, gold, and silver are collected in a 1-gram metallic lead button. Primary contaminants at this stage are arsenic and antimony. These can be removed by heating the button with a mixture of sodium peroxide and sodium hydroxide. The resulting 0.2-gram lead bead is counted in a Compton suppression spectrometer. Carrier yields are determined by reirradiation of the lead beads. This procedure has been applied to the U.S.G.S. Standard Rock PCC-1. and samples from K/T boundary sites in the Western Interior of North America. (author)

  18. Determination of iodine in biological samples by neutron activation analysis (NAA)

    International Nuclear Information System (INIS)

    Geetha, P.V.; Karunakara, N.; Prabhu, Ujwal; Yashodhara, I.; Ravi, P.M.; Sudhakar, J.; Ajith, Nicy; Swain, K.K.; Verma, R.; Reddy, A.V.R.; Acharya, R.

    2010-01-01

    During normal operating conditions of a nuclear reactor, the release of radionuclides to the environment will be extremely low and well within the limits. Radioiodine ( 131 I) is one of the radionuclides likely to get released into the atmosphere in case of a reactor accident. During the short initial phase of release of radioactivity, 131 I is rapidly transferred to milk, leading to significant thyroid dose to those consuming milk, especially infant and children. Hence, studies on Iodine transfer through grass-cow-milk is very important. Extensive studies on transfer for 131 I through grass-cow-milk pathway after Chernobyl accident has been reported. But, under normal operational conditions of the power reactor, 131 I is not present in measurable concentration in environmental matrices of a nuclear power generating station. Stable iodine is present in all environmental samples and from the concentration of stable iodine in grass and milk, one can estimate the transfer factor. The measurement of stable iodine in environmental sample is very challenging because of its extremely low concentration. Neutron activation analysis can be used for estimation of stable iodine in the environment after suitably optimizing the condition to minimize interferences. A method has been developed based on thermal neutron activation analysis (NAA) to estimate the iodine concentration present in grass and cow milk

  19. Application of activation analysis for determination of some elements in cassiterite samples

    International Nuclear Information System (INIS)

    Armelin, Maria Jose Aguirre

    1978-01-01

    This work consists in the development of an analytical method using activation by thermal neutrons for the determination of some minor elements and traces present in cassiterite (tin ore). This method was then applied to determine these elements in samples of cassiterite from different regions of Brazil. An analysis was made of the mineralogy characteristic of cassiterite as well as of the minerals most commonly associated with it. Four main types of interference were found to occur in the analysis by activation of trace elements in samples of cassiterite. The method involves the analysis without chemical separation for the determination of some elements and the analysis with chemical separation for the determination of other elements. The steps involved in both types of analysis are described. In the analysis with chemical separation the matrix element (tin) is separated by distillation in an H 2 SO 4 -HBr medium, after fusion of the ore with Na 2 O 2 . Arsine and antimony are determined in the distilled, whereas some lanthanide elements and uranium are determined in the distillation residue by separating them as a group by precipitation with lanthanum fluoride. A discussion on the precision, accuracy and sensibility of the method is also included. (author)

  20. Determination of elemental concentrations in environmental plant samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Datta, J.; Chowdhury, D.P.; Verma, R.; Reddy, A.V.R.

    2012-01-01

    The intake of leafy vegetables in daily diet is very important to meet our nutritional needs. Vegetables provide the essential elements which are necessary and recommended for human growth. However, due to rapid industrialization and urbanization our environment becomes polluted and this affects the normal growth of agricultural products and composition of environmental species. The elemental concentrations present in the environmental samples are good indicators to assess the toxicological levels due to pollution affects. In the present work we have analysed several vegetable plant samples by instrumental neutron activation analysis to determine the elemental concentrations at major, minor and trace levels. The leafy vegetables like spinach, red leafy vegetable, pui, gourd leaf, lettuce and katoua were chosen as these are extensively consumed by local people in eastern part of India. We have determined 15 elements in the above mentioned vegetable samples and some of these are essential elements and some are toxic elements. It was found that Na and K were present as major elements, Fe and Zn as minor elements and As, Ce, Cr, Co, La, Mo, Rb, Sc, Sm, Sr as trace elements. The concentration level of Cr was found to be higher than that of recommended value certified by WHO and National environment quality control for human consumption. The validation of our analytical results have been performed by the Z-score tests through the determination of concentrations of the elements of interest in certified reference materials. (author)

  1. Studies on cellular distribution of elements in human hepatocellular carcinoma samples by molecular activation analysis

    International Nuclear Information System (INIS)

    Deng Guilong; Chen Chunying; Zhang Peiqun; Zhao Jiujiang; Chai Zhifang

    2005-01-01

    The distribution patterns of 17 elements in the subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol of human hepatocellular carcinoma (HCC) and normal liver samples were investigated by using molecular activation analysis (MAA) and differential centrifugation. Their significant difference was checked by the Studient's t-test. These elements exhibit inhomogeneous distributions in each subcellular fraction. Some elements have no significant difference between hepatocellular carcinoma and normal liver samples. However, the concentrations of Br, Ca, Cd and Cs are significantly higher in each component of hepatocarcinoma than in normal liver. The content of Fe in microsome of HCC is significantly lower, almost half of normal liver samples, but higher in other subcellular fractions than in those of normal tissues. The rare earth elements of La and Ce have the patterns similar to Fe. The concentrations of Sb and Zn in nuclei of HCC are obviously lower (P<0.05, P<0.05). The contents of K and Na are higher in cytosol of HCC (P<0.05). The distributions of Ba and Rb show no significant difference between two groups. The relationships of Fe, Cd and K with HCC were also discussed. The levels of some elements in subcellular fractions of tumor were quite different from those of normal liver, which suggested that trace elements might play important roles in the occurrence and development of hepatocellular carcinoma. (authors)

  2. Multielemental determination in Citrus spp bee honey samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Favaro, D.I.T.; Vasconcellos, M.B.A.; Pamplona, B.

    1990-07-01

    Recently interest has grown in the determination of the concentration of inorganic chemical elements in honey bee samples, due its utilization as indicator of environmental pollution in several countries of Europe. In the present work, a method was developed to determine some essential and potentially inorganic elements in honey bee samples by intrumental neutrons activation analysis followed by high resolution gamma ray spectrometry. The honey samples were neutron irradiated during differents times at the nuclear research reactor IEA-Rl of the IPEN-CNEN/SP. The elements Na, Cl, K, Mg and Mn were determined using irradiations of 30 minutes under a thermal neutron flux of 10 12 n.cm -2 .s -1 . With 16 hours of irradiation under a flux of 10 13 n.cm -2 .s -1 and different cooling times, the elements Br, Ca, Au, Sb, Cs, Rb, Zn, Sc, Fe, Co and La were determined. The concentration of the analyzed elements ranged from ng/g to mg/g. In the future, different kinds of bee honey will be analyzed and the characteristic chemical composition of each one will be established. Based on these elemental concentration data, the relationship between the mineral composition of bee honey and its geographical origin can be studied. (author) [pt

  3. Investigation of two slag samples using k0 neutron activation analysis through different standardization methods

    Directory of Open Access Journals (Sweden)

    M. Abd El-Samad

    2010-12-01

    Full Text Available Instrumental neutron activation analysis was used to determine concentrations of several major and trace elements in two slag samples. One slag supplied by one of Steel factory and the other one by an Aluminum factory of Egypt. The aim of the present work is to study the accuracy and precision of Internal Comparator k0 and external comparator k0 methods in industrial application. The two slag samples together with an international reference material Soil-7 and two thin gold foils samples (one bare and the other covered with cadmium were irradiated at the core of the Second Research Egyptian Reactor ET-RR-2 of about 13x10 13n/(cm s. The elemental concentration of 46Sc, 51Cr, 60Co, 65Zn, 74As, 82Br, 85Sr, 86Zr, 110mAg, 122Sb, 134Cs, 131Ba, 140La, 141Ce, 147Nd, 153Sm, 152Eu, 153Gd, 166Ho, 169Yb, 175Hf, 182Ta, 198Au and 233Pa (232Th-series were calculated.

  4. Techniques for sampling nuclear waste tank contents and in situ measurement of activity

    International Nuclear Information System (INIS)

    Lawrence, R.C.

    1978-04-01

    A study was conducted to develop suitable sampling equipment and techniques for characterizing the mechanical properties of nuclear wastes; identifying effective means of measuring radiation levels, temperatures, and neutron fluxes in situ in wastes; and developing a waste core sampler. A portable, stainless steel probe was developed which is placed in the tank through a riser. This probe is built for the insertion of instrumentation that can measure the contents of the tank at any level and take temperature, radiation, and neutron activation readings with reliable accuracy. A simple and reliable instrument for the in situ extraction of waste materials ranging from liquid to concrete-like substances was also developed. This portable, stainless steel waste core sampler can remove up to one liter of radioactive waste from tanks for transportation to hot cell laboratories for analysis of hardness, chemical form, and isotopic content. A cask for transporting the waste samples from the tanks to the laboratory under radiation-protected conditions was also fabricated. This cask was designed with a ''boot'' or inner-seal liner to contain any radioactive wastes that might remain on the outside of the waste core sampling device

  5. Analysis by neutronic activation of samples of a geologic formation of Cuba

    International Nuclear Information System (INIS)

    Capote Rodriguez, G.; Pena Fortes, B.; Padilla Alvarez, R.; Llanes Castro, A.I.; Perez Zayas, G.; Hernandez Rivero, A.T.; Lopez Reyes, M. C.; Ribeiro Guevara, S.; Molina Insfran, J.

    1997-01-01

    The analysis by neutronic activation (AAN) is an analytical non destructive technique of high accuracy and sensibility. These advantages are very utilized in the determination of geological multielemental samples. In the job 22 elements are determined in 9 geological samples pertaining to the complex of dams of acid composition that includes the graphitic micaceous schist and the quartzites of the Canada Formation, developed fundamentally in the fasteners of the anticlinal Victoria (Yac. of Wolframio Lela, Island of the Youth, Cuba) The results obtained are of great importance for the evaluation of the potentiality of these rocks as fountains or of uranium adjusting and for the geologic prognostic of the region in study. The irradiation of the samples was carried out during three campaigns, in two occasions (October 1992 and November 1994) in the reactor of investigations of the ININ of Mexico, with a flow of thermic neutrons of 10a the 13 n.s -1 cm -2 and in an occasion in the nuclear reactor of the CAB (september 1994), with a flow of thermic neutrons of 6x 10 to the 12 n.s-1. The results were processed with the program ACTAM in the CEADEN. (S. Grainger) [es

  6. Microbial Safety of Low Water Activity Foods: Study of Simulated and Durban Household Samples

    Directory of Open Access Journals (Sweden)

    O. A. Ijabadeniyi

    2017-01-01

    Full Text Available Sixty household low water activity foods were examined and a simulative study was conducted in a high sugar, low aw almond and macadamia butter to determine the survival of Bacillus cereus and Staphylococcus aureus ATCC 25923. Results obtained from 60 low aw samples collected at household level had some significant differences (P≤0,05 within food categories amongst the various tests. Spices had the highest number of aerobic bacteria, aerobic spore-formers, anaerobic spore-formers, and S. aureus. Mean aerobic colony counts for nuts and spices were 2.30 log CFU/g and 4.40 log CFU/g, respectively. Pathogens such as Escherichia coli and Cronobacter sakazakii were present in nuts, whilst Salmonella spp. was present in chocolates. This implies that certain low aw foods may present a public health risk. In the simulative study, temperature and high sucrose concentrations played a significant role in the survival of B. cereus and S. aureus ATCC 25923. B. cereus was found to be more osmotolerant at both reduced and elevated temperatures (18°C and 25°C in the 12% sucrose sample in both butters, whilst S. aureus ATCC 25923 seemed to grow better in sucrose-free samples at both temperatures in both butters. This implies that certain low aw foods may present a public health risk. Also, B. cereus, being a spore-forming bacterium, can be osmotolerant at both reduced and elevated temperatures.

  7. Studies on cellular distribution of elements in human hepatocellular carcinoma samples by molecular activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Guilong, Deng [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics, Key Laboratory of Nuclear Analytical Techniques; Department of General Surgery, the Second Affiliated Hospital, School of Medicine, Zhejiang Univ., Hangzhou (China); Chunying, Chen; Peiqun, Zhang; Jiujiang, Zhao; Zhifang, Chai [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics, Key Laboratory of Nuclear Analytical Techniques; Yingbin, Liu; Jianwei, Wang; Bin, Xu; Shuyou, Peng [Department of General Surgery, the Second Affiliated Hospital, School of Medicine, Zhejiang Univ., Hangzhou (China)

    2005-07-15

    The distribution patterns of 17 elements in the subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol of human hepatocellular carcinoma (HCC) and normal liver samples were investigated by using molecular activation analysis (MAA) and differential centrifugation. Their significant difference was checked by the Studient's t-test. These elements exhibit inhomogeneous distributions in each subcellular fraction. Some elements have no significant difference between hepatocellular carcinoma and normal liver samples. However, the concentrations of Br, Ca, Cd and Cs are significantly higher in each component of hepatocarcinoma than in normal liver. The content of Fe in microsome of HCC is significantly lower, almost half of normal liver samples, but higher in other subcellular fractions than in those of normal tissues. The rare earth elements of La and Ce have the patterns similar to Fe. The concentrations of Sb and Zn in nuclei of HCC are obviously lower (P<0.05, P<0.05). The contents of K and Na are higher in cytosol of HCC (P<0.05). The distributions of Ba and Rb show no significant difference between two groups. The relationships of Fe, Cd and K with HCC were also discussed. The levels of some elements in subcellular fractions of tumor were quite different from those of normal liver, which suggested that trace elements might play important roles in the occurrence and development of hepatocellular carcinoma. (authors)

  8. Modelling of bulk superconductor magnetization

    International Nuclear Information System (INIS)

    Ainslie, M D; Fujishiro, H

    2015-01-01

    This paper presents a topical review of the current state of the art in modelling the magnetization of bulk superconductors, including both (RE)BCO (where RE = rare earth or Y) and MgB 2 materials. Such modelling is a powerful tool to understand the physical mechanisms of their magnetization, to assist in interpretation of experimental results, and to predict the performance of practical bulk superconductor-based devices, which is particularly important as many superconducting applications head towards the commercialization stage of their development in the coming years. In addition to the analytical and numerical techniques currently used by researchers for modelling such materials, the commonly used practical techniques to magnetize bulk superconductors are summarized with a particular focus on pulsed field magnetization (PFM), which is promising as a compact, mobile and relatively inexpensive magnetizing technique. A number of numerical models developed to analyse the issues related to PFM and optimise the technique are described in detail, including understanding the dynamics of the magnetic flux penetration and the influence of material inhomogeneities, thermal properties, pulse duration, magnitude and shape, and the shape of the magnetization coil(s). The effect of externally applied magnetic fields in different configurations on the attenuation of the trapped field is also discussed. A number of novel and hybrid bulk superconductor structures are described, including improved thermal conductivity structures and ferromagnet–superconductor structures, which have been designed to overcome some of the issues related to bulk superconductors and their magnetization and enhance the intrinsic properties of bulk superconductors acting as trapped field magnets. Finally, the use of hollow bulk cylinders/tubes for shielding is analysed. (topical review)

  9. Carbon nanotubes grown on bulk materials and methods for fabrication

    Science.gov (United States)

    Menchhofer, Paul A [Clinton, TN; Montgomery, Frederick C [Oak Ridge, TN; Baker, Frederick S [Oak Ridge, TN

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  10. Onset of bulk pinning in BSCCO single crystals

    Science.gov (United States)

    van der Beek, C. J.; Indenbom, M. V.; Berseth, V.; Li, T. W.; Benoit, W.

    1996-11-01

    The long growth defects often found in Bi2Sr2CaCu2O8, “single” crystals effectively weaken the geometrical barrier and lower the field of first flux penetration. This means that the intrinsic (bulk) magnetic properties can be more easily accessed using magnetic measurements. Thus, the onset of strong bulk flux pinning in the sample bulk is determined to lie at T ≈ 40 K, indepedent of whether the field strength is above or below the field of the second peak in the magnetisation.

  11. Determination of ring correction factors for leaded gloves used in grab sampling activities at Hanford tank farms

    Energy Technology Data Exchange (ETDEWEB)

    RATHBONE, B.A.

    1999-06-24

    This study evaluates the effectiveness of lead lined gloves in reducing extremity dose from two sources specific to tank waste sampling activities: (1) sludge inside glass sample jars and (2) sludge as thin layer contamination on the exterior surface of sample jars. The response of past and present Hanford Extremity Dosimeters (ring) designs under these conditions is also evaluated.

  12. Determination of ring correction factors for leaded gloves used in grab sampling activities at Hanford tank farms

    International Nuclear Information System (INIS)

    RATHBONE, B.A.

    1999-01-01

    This study evaluates the effectiveness of lead lined gloves in reducing extremity dose from two sources specific to tank waste sampling activities: (1) sludge inside glass sample jars and (2) sludge as thin layer contamination on the exterior surface of sample jars. The response of past and present Hanford Extremity Dosimeters (ring) designs under these conditions is also evaluated

  13. Thermal neutron self-shielding correction factors for large sample instrumental neutron activation analysis using the MCNP code

    International Nuclear Information System (INIS)

    Tzika, F.; Stamatelatos, I.E.

    2004-01-01

    Thermal neutron self-shielding within large samples was studied using the Monte Carlo neutron transport code MCNP. The code enabled a three-dimensional modeling of the actual source and geometry configuration including reactor core, graphite pile and sample. Neutron flux self-shielding correction factors derived for a set of materials of interest for large sample neutron activation analysis are presented and evaluated. Simulations were experimentally verified by measurements performed using activation foils. The results of this study can be applied in order to determine neutron self-shielding factors of unknown samples from the thermal neutron fluxes measured at the surface of the sample

  14. Comparison of two treatments for the removal of selected organic micropollutants and bulk organic matter: conventional activated sludge followed by ultrafiltration versus membrane bioreactor.

    Science.gov (United States)

    Sahar, E; Ernst, M; Godehardt, M; Hein, A; Herr, J; Kazner, C; Melin, T; Cikurel, H; Aharoni, A; Messalem, R; Brenner, A; Jekel, M

    2011-01-01

    The potential of membrane bioreactor (MBR) systems to remove organic micropollutants was investigated at different scales, operational conditions, and locations. The effluent quality of the MBR system was compared with that of a plant combining conventional activated sludge (CAS) followed by ultrafiltration (UF). The MBR and CAS-UF systems were operated and tested in parallel. An MBR pilot plant in Israel was operated for over a year at a mixed liquor suspended solids (MLSS) range of 2.8-10.6 g/L. The MBR achieved removal rates comparable to those of a CAS-UF plant at the Tel-Aviv wastewater treatment plant (WWTP) for macrolide antibiotics such as roxythromycin, clarithromycin, and erythromycin and slightly higher removal rates than the CAS-UF for sulfonamides. A laboratory scale MBR unit in Berlin - at an MLSS of 6-9 g/L - showed better removal rates for macrolide antibiotics, trimethoprim, and 5-tolyltriazole compared to the CAS process of the Ruhleben sewage treatment plant (STP) in Berlin when both were fed with identical quality raw wastewater. The Berlin CAS exhibited significantly better benzotriazole removal and slightly better sulfamethoxazole and 4-tolyltriazole removal than its MBR counterpart. Pilot MBR tests (MLSS of 12 g/L) in Aachen, Germany, showed that operating flux significantly affected the resulting membrane fouling rate, but the removal rates of dissolved organic matter and of bisphenol A were not affected.

  15. Activation analysis of rare-earth elements in opium and cannabis samples. [Neutron reactions

    Energy Technology Data Exchange (ETDEWEB)

    Henke, G [Muenster Univ. (Germany, F.R.). Inst. fuer Pharmazeutische Chemie

    1977-01-01

    Rare-earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of the world were determined by destructive NAA. Because of the greater concentrations of Ca, P, K, Fe, Na and Si in plant materials, rare-earth elements were isolated after neutron irradiation and determined by gamma-spectrometry. The main steps of the method are: Preashing of 1 g Cannabis resin, 2.5 g Cannabis, or 7.5 g Opium, respectively, in quartz ampoules (5 h, 500 deg C). Neutron irradiation, 24 h at 5x10/sup 13/n cm/sup -2/sec/sup -1/. Cooling period 2-3 days. After addition of 0.1 ..mu..Ci /sup 139/Ce and rare-earth carriers wet ashing of irradiated samples with H/sub 2/SO/sub 4//HNO/sub 3/, followed by alternate addition of HNO/sub 3/ and H/sub 2/O/sub 2/ (30%). Precipitation and removal of silicates, precipitation of fluorides, precipitation of hydroxides. Dissolution of hydroxides in HCl. Extraction with di-(2-ethylhexyl)phosphate (DEHP)/toluene and twice back-extraction of rare earths, gamma-spectrometry of HCl phase. Due to sample activity and half-life of nuclides, three measurements were made on each sample: 2 days (for La, Sm, Gd, Ho, Er, Yb); 14 days (for Nd, Lu) and 30 days after irradiation (for Ce, Eu, Tb). Great variations in absolute element concentrations, but only small significant differences of rare earth concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond to the relative abundances of the rare earths in the upper continental earth's crust.

  16. Activation analysis of rare-earth elements in opium and cannabis samples

    International Nuclear Information System (INIS)

    Henke, G.

    1977-01-01

    Rare-earth concentrations in 65 Opium, Cannabis and Cannabis resin samples seized from various parts of the world were determined by destructive NAA. Because of the greater concentrations of Ca, P, K, Fe, Na and Si in plant materials, rare-earth elements were isolated after neutron irradiation and determined by gamma-spectrometry. The main steps of the method are: Preashing of 1 g Cannabis resin, 2.5 g Cannabis or 7.5 g Opium, respectively, in quartz ampoules (5 h, 500 deg C). Neutron irradiation, 24 h at 5x10 13 n cm -2 sec -1 . Cooling period 2-3 days. After addition of 0.1 μCi 139 Ce and rare-earth carriers wet ashing of irradiated samples with H 2 SO 4 /HNO 3 , followed by alternate addition of HNO 3 and H 2 O 2 (30%). Precipitation and removal of silicates, precipitation of fluorides, precipitation of hydroxides. Dissolution of hydroxides in HCl. Extraction with di-(2-ethylhexyl)phosphate (DEHP)/toluene and twice back-extraction of rare earths, gamma-spectrometry of HCl phase. Due to sample activity and half-life of nuclides, three measurements were made on each sample: 2 days (for La, Sm, Gd, Ho, Er, Yb); 14 days (for Nd, Lu) and 30 days after irradiation (for Ce, Eu, Tb). Great variations in absolute element concentrations, but only small significant differences of rare earth concentration ratios were found, indicating inconsiderable biogeochemical fractionation. The mean values of these ratios correspond to the relative abundances of the rare earths in the upper continental earth's crust. (T.G.)

  17. Neutron activation analysis technique and X-ray fluorescence in bovine liver sample

    International Nuclear Information System (INIS)

    Maihara, V.A.; Favaro, D.I.T.; Vasconcellos, M.B.A.; Sato, I.M.; Salvador, V.L.

    2002-01-01

    Many analytical techniques have been used in food and diet analysis in order to determine a great number of nutritional elements, ranging from percentage to ng g -1 , with high sensitivity and accuracy. Instrumental Neutron activation Analysis (INAA) has been employed to certificate many trace elements in biological reference materials. More recently, the X-Ray Fluorescence (FRX-WD) has been also used to determine some essential elements in food samples. The INAA has been applied in nutrition studies in our laboratory at IPEN since the 80 s. For the development of analytical methodologies the use of the reference materials with the same characteristics of the sample analyzed is essential. Several Brazilian laboratories do not have conditions to use these materials due their high cost.In this paper preliminary results of commercial bovine liver sample analyses obtained by INAA and WD-XRF methods are presented. This sample was prepared to be a Brazilian candidate of reference material for a group of laboratories participating in a research project sponsored by FAPESP. The concentrations of some elements like Cl, K, Na, P, S and trace elements Br, Ca, Co, Cu, Fe, Mg, Mn, Mo, Rb, Se and Zn were determined by INAA and WD-XFR. For validation methodology of both techniques, NIST SRM 1577b Bovine Liver reference material was analyzed and the detection limits were calculated. The concentrations of elements determined by both analytical techniques were compared by using the Student's t-test and for Cl, Cu, Fe, K, Mg, Na, Rn and Zn the results do show no statistical difference for 95% significance level. (author)

  18. MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Allevato, V. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Paolillo, M. [Department of Physical Sciences, University Federico II, via Cinthia 6, I-80126 Naples (Italy); Papadakis, I. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion (Greece); Pinto, C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

    2013-07-01

    We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

  19. A comparative study of 232Th and 238U activity estimation in soil samples by gamma spectrometry and neutron activation analysis technique

    International Nuclear Information System (INIS)

    Anilkumar, Rekha; Anilkumar, S.; Narayani, K.; Babu, D.A.R.; Sharma, D.N.

    2012-01-01

    Neutron activation analysis (NAA) is a well-established analytical technique. It has many advantages as compared to the other commonly used techniques. NAA can be performed in a variety of ways depending on the element, its activity level in the sample, interference from the sample matrix and other elements, etc. This technique is used to get high analytical sensitivity and low detection limits (ppm to ppb). The high sensitivity is due to the irradiation at high neutron flux available from the research reactors and the activity measurement is done using high resolution HPGe detectors. In this paper, the activity estimation of soil samples using neutron activation and direct gamma spectrometry methods are compared. Even though the weights of samples considered and samples preparation methods are different for these two methods, the estimated activity values are comparable. (author)

  20. BDNF Methylation and Maternal Brain Activity in a Violence-Related Sample.

    Directory of Open Access Journals (Sweden)

    Dominik A Moser

    Full Text Available It is known that increased circulating glucocorticoids in the wake of excessive, chronic, repetitive stress increases anxiety and impairs Brain-Derived Neurotrophic Factor (BDNF signaling. Recent studies of BDNF gene methylation in relation to maternal care have linked high BDNF methylation levels in the blood of adults to lower quality of received maternal care measured via self-report. Yet the specific mechanisms by which these phenomena occur remain to be established. The present study examines the link between methylation of the BDNF gene promoter region and patterns of neural activity that are associated with maternal response to stressful versus non-stressful child stimuli within a sample that includes mothers with interpersonal violence-related PTSD (IPV-PTSD. 46 mothers underwent fMRI. The contrast of neural activity when watching children-including their own-was then correlated to BDNF methylation. Consistent with the existing literature, the present study found that maternal BDNF methylation was associated with higher levels of maternal anxiety and greater childhood exposure to domestic violence. fMRI results showed a positive correlation of BDNF methylation with maternal brain activity in the anterior cingulate (ACC, and ventromedial prefrontal cortex (vmPFC, regions generally credited with a regulatory function toward brain areas that are generating emotions. Furthermore we found a negative correlation of BDNF methylation with the activity of the right hippocampus. Since our stimuli focus on stressful parenting conditions, these data suggest that the correlation between vmPFC/ACC activity and BDNF methylation may be linked to mothers who are at a disadvantage with respect to emotion regulation when facing stressful parenting situations. Overall, this study provides evidence that epigenetic signatures of stress-related genes can be linked to functional brain regions regulating parenting stress, thus advancing our understanding of

  1. Methods for preparing comparative standards and field samples for neutron activation analysis of soil

    International Nuclear Information System (INIS)

    Glasgow, D.C.; Dyer, F.F.; Robinson, L.

    1994-01-01

    One of the more difficult problems associated with comparative neutron activation analysis (CNAA) is the preparation of standards which are tailor-made to the desired irradiation and counting conditions. Frequently, there simply is not a suitable standard available commercially, or the resulting gamma spectrum is convoluted with interferences. In a recent soil analysis project, the need arose for standards which contained about 35 elements. In response, a computer spreadsheet was developed to calculate the appropriate amount of each element so that the resulting gamma spectrum is relatively free of interferences. Incorporated in the program are options for calculating all of the irradiation and counting parameters including activity produced, necessary flux/bombardment time, counting time, and appropriate source-to-detector distance. The result is multi-element standards for CNAA which have optimal concentrations. The program retains ease of use without sacrificing capability. In addition to optimized standard production, a novel soil homogenization technique was developed which is a low cost, highly efficient alternative to commercially available homogenization systems. Comparative neutron activation analysis for large scale projects has been made easier through these advancements. This paper contains details of the design and function of the NAA spreadsheet and innovative sample handling techniques

  2. Methods for preparing comparative standards and field samples for neutron activation analysis of soil

    International Nuclear Information System (INIS)

    Glasgow, D.C.; Dyer, F.F.; Robinson, L.

    1995-01-01

    One of the more difficult problems associated with comparative neutron activation analysis (CNAA) is the preparation of standards which are tailor-made to the desired irradiation and counting conditions. Frequently, there simply is not a suitable standard available commercially, or the resulting gamma spectrum is convoluted with interferences. In a recent soil analysis project, the need arose for standards which contained about 35 elements. In response, a computer spreadsheet was developed to calculate the appropriate amount of each element so that the resulting gamma spectrum is relatively free of interferences. Incorporated in the program are options for calculating all of the irradiation and counting parameters including activity produced, necessary flux/bombardment time, counting time, and appropriate source-to-detector distance. The result is multi-element standards for CNAA which have optimal concentrations. The program retains ease of use without sacrificing capability. In addition to optimized standard production, a novel soil homogenization technique was developed which is a low cost, highly efficient alternative to commercially available homogenization systems. Comparative neutron activation analysis for large scale projects has been made easier through these advancements. This paper contains details of the design and function of the NAA spreadsheet and innovative sample handling techniques. (author) 7 refs.; 5 tabs

  3. Validation of the TTM processes of change measure for physical activity in an adult French sample.

    Science.gov (United States)

    Bernard, Paquito; Romain, Ahmed-Jérôme; Trouillet, Raphael; Gernigon, Christophe; Nigg, Claudio; Ninot, Gregory

    2014-04-01

    Processes of change (POC) are constructs from the transtheoretical model that propose to examine how people engage in a behavior. However, there is no consensus about a leading model explaining POC and there is no validated French POC scale in physical activity This study aimed to compare the different existing models to validate a French POC scale. Three studies, with 748 subjects included, were carried out to translate the items and evaluate their clarity (study 1, n = 77), to assess the factorial validity (n = 200) and invariance/equivalence (study 2, n = 471), and to analyze the concurrent validity by stage × process analyses (study 3, n = 671). Two models displayed adequate fit to the data; however, based on the Akaike information criterion, the fully correlated five-factor model appeared as the most appropriate to measure POC in physical activity. The invariance/equivalence was also confirmed across genders and student status. Four of the five existing factors discriminated pre-action and post-action stages. These data support the validation of the POC questionnaire in physical activity among a French sample. More research is needed to explore the longitudinal properties of this scale.

  4. Associations Between Parental BMI and the Family Nutrition and Physical Activity Environment in a Community Sample.

    Science.gov (United States)

    Williams, Joel E; Helsel, Brian; Griffin, Sarah F; Liang, Jessica

    2017-12-01

    The purpose of this study was to examine the relationship between parental BMI and the family environment and determine if differences exist in child diet and physical activity related parenting behaviors by parental BMI in a community sample of families recruited through elementary schools in a local school district. We found an association between parental BMI category and family nutrition and physical activity (FNPA) score. Families with an underweight or normal weight parent had a larger proportion (64.3%) of high (indicating a healthier family environment) FNPA scores and families with an overweight or obese parent had a smaller proportion (45.2%) of high FNPA scores (χ 2  = 5.247, P = 0.022). Families with a parent who was overweight or obese had 2.18 times the odds (95% CI 1.11-4.27) of being in the low FNPA ("less healthy" environment) group. Further, underweight/normal weight parents reported higher levels of monitoring of child diet (Z = -3.652, P authoritative parenting behaviors were associated with a less obesogenic home environment and a positive parenting style related to child eating and physical activity behaviors.

  5. Composition of the volatile fraction of a sample of Brazilian green propolic and its phytotoxic activity.

    Science.gov (United States)

    Fernandes-Silva, Caroline C; Lima, Carolina A; Negri, Giuseppina; Salatino, Maria L F; Salatino, Antonio; Mayworm, Marco A S

    2015-12-01

    Propolis is a resinous material produced by honeybees, containing mainly beeswax and plant material. Despite the wide spectrum of biological activity of propolis, to our knowledge no studies have been carried out about phytotoxic properties of Brazilian propolis and its constituents. The aims of this study were to analyze the chemical composition and to evaluate the phytotoxic activity of the volatile fraction of a sample of Brazilian green propolis. Main constituents are the phenylpropanoid 3-prenylcinnamic acid allyl ester (26.3%) and the sesquiterpene spathulenol (23.4%). Several other sesquiterpenes and phenylpropanoids, in addition to linalool and α-terpineol (monoterpenes), were also detected. The activity of solutions of the volatile fraction at 1.0, 0.5 and 0.1% was tested on lettuce seeds and seedlings. The solution at 1% inhibited completely the seed germination and solutions at 0.1 and 0.5% reduced the germination rate index. The solution at 0.5% reduced the growth of the hypocotyl-radicle axis and the development of the cotyledon leaf. The chemical composition of the volatile fraction of this Brazilian green propolis is different from those previously described, and these results may contribute to a better understanding about the chemical variations in propolis. The volatile fraction of Brazilian green propolis influences both germination of seed lettuce and the growth of its seedlings, showing an phytotoxic potential. © 2014 Society of Chemical Industry.

  6. Diversity and killer activity of yeasts in Malaysian fermented food samples.

    Science.gov (United States)

    Lim, S L; Tay, S T

    2011-08-01

    The biodiversity and the killer activity of yeasts isolated from various types of fermented food in Malaysia were investigated in this study. Of 252 yeasts isolated from 48 fermented food samples in this study, 19 yeast species were identified based on sequence analysis of the ITS1-5.8S-ITS2 partial fragments of the yeasts. A total of 29 (11.5%) of the yeast isolates demonstrated killer activity to at least one Candida species tested in this study; including 22 isolates of Trichosporon asahii, 4 isolates of Pichia anomala, and one isolate each of Pichia norvegensis, Pichia fermentans and Issatchenkia orientalis, respectively. The presence of killer yeasts reflects antagonism that occurs during microbial interaction in the fermented food, whereby certain yeasts produce killer toxins and possibly other toxic substances in competition for limited nutrients and space. The anti-Candida activity demonstrated by killer yeasts in this study should be further explored for development of alternative therapy against candidiasis.

  7. Novel sampling methods for atmospheric semi-volatile organic compounds (SOCs) in a high altitude alpine environment.

    Science.gov (United States)

    Offenthaler, I; Jakobi, G; Kaiser, A; Kirchner, M; Kräuchi, N; Niedermoser, B; Schramm, K-W; Sedivy, I; Staudinger, M; Thanner, G; Weiss, P; Moche, W

    2009-12-01

    High- and low-volume active air samplers as well as bulk deposition samplers were developed to sample atmospheric SOCs under the adverse conditions of a mountain environment. Active sampling employed separate filters for different European source regions. Filters were switched depending on daily trajectory forecasts, whose accuracy was evaluated post hoc. The sampling continued on three alpine summits over five periods of four months. The prevailing trajectories varied stronger between sampling periods than between stations. The sampling equipment (active and bulk deposition) proved dependable for operation in a mountain environment, with idle times being mainly due to non-routine manipulations and connectivity.

  8. Bulk metallic glass matrix composites

    International Nuclear Information System (INIS)

    Choi-Yim, H.; Johnson, W.L.

    1997-01-01

    Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

  9. APPLICATION OF NEUTRON ACTIVATION ANALYSIS IN CHARACTERIZATION OF ENVIRONMENTAL SRM SAMPLES

    Directory of Open Access Journals (Sweden)

    Diah Dwiana Lestiani

    2010-06-01

    Full Text Available Neutron activation analysis (NAA is a nuclear technique that is excellent, multi-elemental, sensitive and has limit detection up to nanogram level. The application of NAA in analysis of Standard Reference Material (SRM National Institute of Standard Technology (NIST 1633b Coal Fly Ash and SRM NIST 1646a Estuarine Sediment was carried out for NAA laboratory inter-comparison program. The samples were distributed by Technology Centre for Nuclear Industry Material, National Nuclear Energy Agency as a coordinator of the inter-comparison program. The samples were irradiated in rabbit facility of G.A. Siwabessy reactor with neutron flux ~ 1013 n.cm-2.s-1, and counted with HPGe spectrometry gamma detector. Several trace elements in these samples were detected. The concentration of Al, Mg, K, Na and Ti in SRM NIST 1633b were 15.11, 7.35, 2.09, 0.192 and 0.756% respectively and the concentration of As, Cr, Mn, Se, V, Sb, Co, Cs, La, Sc and Sm were 137.0, 195.6, 129.4, 9.61, 305.8, 5.45, 56.2, 11.18, 83.73, 41.1 and 19.13 mg/kg respectively. The analysis result in SRM NIST 1646a of the concentration of Al and Na were 2.15 and 0.70% and the concentration of As, Cr, Co, La and Sc were 5.75, 36.3, 4.58, 15.67 and 4.00 mg/kg respectively. These results analysis had relative bias and u-test ranged from 0.4-11.3% and 0.15-2.25. The accuracy and precision evaluation based on International Atomic Energy Agency (IAEA criteria was also applied. The result showed that NAA technique is applicable for the environmental samples analysis, and it also showed that the NAA laboratory in BATAN Bandung has a good performance.   Keywords: NAA, inter-comparison, estuarine sediment, coal fly ash, environmental samples

  10. A time-sorting pitfall trap and temperature datalogger for the sampling of surface-active arthropods

    OpenAIRE

    McMunn, Marshall S.

    2017-01-01

    Nearly all arthropods display consistent patterns of activity according to time of day. These patterns of activity often limit the extent of animal co-occurrence in space and time. Quantifying when particular species are active and how activity varies with environmental conditions is difficult without the use of automated devices due to the need for continuous monitoring. Time-sorting pitfall traps passively collect active arthropods into containers with known beginning and end sample times. ...

  11. Active learning for clinical text classification: is it better than random sampling?

    Science.gov (United States)

    Figueroa, Rosa L; Ngo, Long H; Goryachev, Sergey; Wiechmann, Eduardo P

    2012-01-01

    Objective This study explores active learning algorithms as a way to reduce the requirements for large training sets in medical text classification tasks. Design Three existing active learning algorithms (distance-based (DIST), diversity-based (DIV), and a combination of both (CMB)) were used to classify text from five datasets. The performance of these algorithms was compared to that of passive learning on the five datasets. We then conducted a novel investigation of the interaction between dataset characteristics and the performance results. Measurements Classification accuracy and area under receiver operating characteristics (ROC) curves for each algorithm at different sample sizes were generated. The performance of active learning algorithms was compared with that of passive learning using a weighted mean of paired differences. To determine why the performance varies on different datasets, we measured the diversity and uncertainty of each dataset using relative entropy and correlated the results with the performance differences. Results The DIST and CMB algorithms performed better than passive learning. With a statistical significance level set at 0.05, DIST outperformed passive learning in all five datasets, while CMB was found to be better than passive learning in four datasets. We found strong correlations between the dataset diversity and the DIV performance, as well as the dataset uncertainty and the performance of the DIST algorithm. Conclusion For medical text classification, appropriate active learning algorithms can yield performance comparable to that of passive learning with considerably smaller training sets. In particular, our results suggest that DIV performs better on data with higher diversity and DIST on data with lower uncertainty. PMID:22707743

  12. Bulk viscosity and cosmological evolution

    International Nuclear Information System (INIS)

    Beesham, A.

    1996-01-01

    In a recent interesting paper, Pimentel and Diaz-Rivera (Nuovo Cimento B, 109(1994) 1317) have derived several solutions with bulk viscosity in homogeneous and isotropic cosmological models. They also discussed the properties of these solutions. In this paper the authors relate the solutions of Pimentel and Diaz-Rivera by simple transformations to previous solutions published in the literature, showing that all the solutions can be derived from the known existing ones. Drawbacks to these approaches of studying bulk viscosity are pointed out, and better approaches indicated

  13. Measurement of low-level beta activity of samples in liquid state using plastic scintillator vials

    International Nuclear Information System (INIS)

    Wezranowski, E.; Panczyk, E.; Radwan, M.

    1977-01-01

    Plastic scintillation vials having walls from a plastic scintillator and the bottom from perspex were used. Wall thickness was 0.8 to 3 mm. The solution radioactivity was measured by a scintillation beta spectrometer. The total measurement errors were found for the following radionuclides: 14 C +-3.7%; 204 Tl +-3%; 32 P +-2.8%; 137 Cs +-2%, and 72 Ga +-5%. Detection efficiency was found to decrease rapidly with the solution layer thickness. For a solution thickness of 0.2 mm the highest detection efficiency was observed with the 4% measurement error. Linear dependence was found of detection efficiency on beta energy. For a solution layer thickness of 0.2 mm the minimum measurable activities were determined to be 30.3 pCi for 14 C and 2.12 pCi for 32 P. The use of the above vials permits quick and simple measurement without sample chemical preparation. (J.P.)

  14. Elemental analysis of two Egyptian iron ores and produced industrial iron samples by neutron activation analysis

    International Nuclear Information System (INIS)

    Sroor, A.; Abdel-Basset, N.; Abdel-Haleem, A.S.; Hassan, A.M.

    2001-01-01

    Elemental analysis of two iron ores and initial industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were performed by the instrumental neutron activation analysis technique. Five samples of each type were irradiated for 48 h in a thermal neutron flux of 4x10 12 n/cm 2 s in the first Egyptian research reactor ET-RR-1. Also, the Pneumatic Irradiation Rabbit System (PIRS), attached to the reactor ET-RR-1 in Inshass, was used to measure short-life elements. The γ-ray spectra were obtained with a hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. Implications of the elemental concentration values obtained are presented

  15. Determination of rhenium in biological and environmental samples by radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Kucera, J.; Mizera, J.; Randa, Z.; Byrne, A.R.; Lucanikova, M.

    2006-01-01

    Radiochemical neutron activation procedures using liquid-liquid extraction with tetraphenylarsonium chloride in chloroform from 1 M HCl and solid extraction with ALIQUAT 336 incorporated in a polyacrylonitrile binding matrix from 0.1 M HCl were developed for accurate determination of rhenium in biological and environmental samples at the sub-ng.g -1 level. Concentrations of Re in the range of 0.1 to 2.4 ng.g -1 were determined in several botanical reference materials (RM), while in a RM of road dust a value of approx. 10 ng.g -1 was found. Significantly elevated values of Re, up to 90 ng.g -1 , were found in seaweed (brown algae). Results for Re in the brown algae Fucus vesiculosus in which elevated 99 Tc values had previously been determined suggest possible competition between Re and Tc in the accumulation process. (author)

  16. Multielemental analysis of Brazilian milk powder and bread samples by neutron activation

    International Nuclear Information System (INIS)

    Maihara, V.A.; Vasconcellos, M.B.A.

    1988-01-01

    The concentrations of Na, Cl, Mn, Br, Fe, Zn, Rb, Sb, Sc, Cr, Al and Mg were determined in some types of bread and in some brands of milk powder consumed in the city of Sao Paulo (SP - Brasil), by instrumental neutron activation analysis. Radiochemical separations were carried out by means of retention of 24 Na on hydrated antimony pentoxide (HAP) from a 8N HCl solution, after digestion of the organic matter. Thus the radioisotopes 64 Cu, 69m Zn and 140 La could be determined in the effluent solution. The detection limits of the trace elements analyzed in bread and milk powder samples were determined using the Currie and Girardi criterions. (author) 22 refs.; 2 figs.; 7 tabs

  17. Measurement of arsenic in sectioned hair samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Guinn, V.P.; Gavrilas-Guinn, M.; Demiralp, R.

    1994-01-01

    In a recent Texas murder case, bundles of head hair from the female victim (aligned with all root ends together) were washed, cut into 7 mm sections, air-dried and weighed, activated in a nuclear reactor neutron flux, and then counted with a Ge(Li) detector/4096-channel gamma-ray spectrometer. In each of the 15 samples, the 559 keV gamma-ray peak of 26.3 hour 76 As was measured. In the section closest to the scalp, an arsenic concentration of 107 ppm was found (cf. a 'normal' level of about 1 ppm As). Barium ingestion was also possible so Ba was looked for, but not found. The victim's husband was found guilty of murder by chronic arsenic poisoning. (author) 2 refs.; 1 fig.; 1 tab

  18. Study of gamma ray analysis software's. Application to activation analysis of geological samples

    International Nuclear Information System (INIS)

    Silva, Luiz Roberto Nogueira da

    1998-01-01

    A comparative evaluation of the gamma-ray analysis software VISPECT, in relation to two commercial gamma-ray analysis software packages, OMNIGAM (EG and G Ortec) and SAMPO 90 (Canberra) was performed. For this evaluation, artificial gamma ray spectra were created, presenting peaks of different intensities and located at four different regions of the spectrum. Multiplet peaks with equal and different intensities, but with different channel separations, were also created. The results obtained showed a good performance of VISPECT in detecting and analysing single and multiplet peaks of different intensities in the gamma-ray spectrum. Neutron activation analysis of the geological reference material GS-N (IWG-GIT) and of the granite G-94, used in a Proficiency Testing Trial of Analytical Geochemistry Laboratories, was also performed , in order to evaluate the VISEPCT software in the analysis of real samples. The results obtained by using VISPECT were as good or better than the ones obtained using the other programs. (author)

  19. Influence of Soap Characteristics and Food Service Facility Type on the Degree of Bacterial Contamination of Open, Refillable Bulk Soaps.

    Science.gov (United States)

    Schaffner, Donald W; Jensen, Dane; Gerba, Charles P; Shumaker, David; Arbogast, James W

    2018-02-01

    Concern has been raised regarding the public health risks from refillable bulk-soap dispensers because they provide an environment for potentially pathogenic bacteria to grow. This study surveyed the microbial quality of open refillable bulk soap in four different food establishment types in three states. Two hundred ninety-six samples of bulk soap were collected from food service establishments in Arizona, New Jersey, and Ohio. Samples were tested for total heterotrophic viable bacteria, Pseudomonas, coliforms and Escherichia coli, and Salmonella. Bacteria were screened for antibiotic resistance. The pH, solids content, and water activity of all soap samples were measured. Samples were assayed for the presence of the common antibacterial agents triclosan and parachlorometaxylenol. More than 85% of the soap samples tested contained no detectable microorganisms, but when a sample contained any detectable microorganisms, it was most likely contaminated at a very high level (∼7 log CFU/mL). Microorganisms detected in contaminated soap included Klebsiella oxytoca, Serratia liquefaciens, Shigella sonnei, Enterobacter gergoviae, Serratia odorifera, and Enterobacter cloacae. Twenty-three samples contained antibiotic-resistant organisms, some of which were resistant to two or more antibiotics. Every sample containing less than 4% solids had some detectable level of bacteria, whereas no samples with greater than 14% solids had detectable bacteria. This finding suggests the use of dilution and/or low-cost formulations as a cause of bacterial growth. There was a statistically significant difference ( P = 0.0035) between the fraction of bacteria-positive samples with no detected antimicrobial agent (17%) and those containing an antimicrobial agent (7%). Fast food operations and grocery stores were more likely to have detectable bacteria in bulk-soap samples compared with convenience stores ( P food service establishments.

  20. Sampling and analytical methodologies for instrumental neutron activation analysis of airborne particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-01

    The IAEA supports a number of projects having to do with the analysis of airborne particulate matter by nuclear techniques. Most of this work involves the use of activation analysis in its various forms, particularly instrumental neutron activation analysis (INAA). This technique has been widely used in many different countries for the analysis of airborne particulate matter, and there are already many publications in scientific journals, books and reports describing such work. The present document represents an attempt to summarize the most important features of INAA as applied to the analysis of airborne particulate matter. It is intended to serve as a set of guidelines for use by participants in the IAEA's own programmes, and other scientists, who are not yet fully experienced in the application of INAA to airborne particulate samples, and who wish either to make a start on using this technique or to improve their existing procedures. The methodologies for sampling described in this document are of rather general applicability, although they are presented here in a way that takes account of the particular requirements arising from the use of INAA as the analytical technique. The analytical part of the document, however, is presented in a form that is applicable only to INAA. (Subsequent publications in this series are expected to deal specifically with other nuclear related techniques such as energy dispersive X ray fluorescence (ED-XRF) and particle induced X ray emission (PIXE) analysis). Although the methods and procedures described here have been found through experience to yield acceptable results, they should not be considered mandatory. Any other procedure used should, however, be chosen to be capable of yielding results at least of equal quality to those described.

  1. Sampling and analytical methodologies for instrumental neutron activation analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    1992-01-01

    The IAEA supports a number of projects having to do with the analysis of airborne particulate matter by nuclear techniques. Most of this work involves the use of activation analysis in its various forms, particularly instrumental neutron activation analysis (INAA). This technique has been widely used in many different countries for the analysis of airborne particulate matter, and there are already many publications in scientific journals, books and reports describing such work. The present document represents an attempt to summarize the most important features of INAA as applied to the analysis of airborne particulate matter. It is intended to serve as a set of guidelines for use by participants in the IAEA's own programmes, and other scientists, who are not yet fully experienced in the application of INAA to airborne particulate samples, and who wish either to make a start on using this technique or to improve their existing procedures. The methodologies for sampling described in this document are of rather general applicability, although they are presented here in a way that takes account of the particular requirements arising from the use of INAA as the analytical technique. The analytical part of the document, however, is presented in a form that is applicable only to INAA. (Subsequent publications in this series are expected to deal specifically with other nuclear related techniques such as energy dispersive X ray fluorescence (ED-XRF) and particle induced X ray emission (PIXE) analysis). Although the methods and procedures described here have been found through experience to yield acceptable results, they should not be considered mandatory. Any other procedure used should, however, be chosen to be capable of yielding results at least of equal quality to those described

  2. A comparison of passive and active acoustic sampling for a bat community impacted by White-nose syndrome

    Science.gov (United States)

    Coleman, Laci S.; Ford, W. Mark; Dobony, Christopher A.; Britzke, Eric R.

    2014-01-01

    In the summers of 2011 and 2012, we compared passive and active acoustic sampling for bats at 31 sites at Fort Drum Military Installation, New York. We defined active sampling as acoustic sampling that occurred in 30-min intervals between the hours of sunset and 0200 with a user present to manipulate the directionality of the microphone. We defined passive sampling as acoustic sampling that occurred over a 12-h period (1900–0700 hours) without a user present and with the microphone set in a predetermined direction. We detected seven of the nine possible species at Fort Drum, including the federally endangered Indiana bat Myotis sodalis, the proposed-for-listing northern bat M. septentrionalis, the little brown bat M. lucifugus, and the big brown bat Eptesicus fuscus, which are impacted by white-nose syndrome (WNS); and the eastern red bat Lasiurus borealis, the hoary bat L. cinereus, and the silver-haired bat Lasionycteris noctivagans, which are not known to be impacted by WNS. We did not detect two additional WNS-impacted species known to historically occur in the area: the eastern small-footed bat Myotis leibii and the tri-colored bat Perimyotis subflavus. Single-season occupancy models revealed lower detection probabilities of all detected species using active sampling versus passive sampling. Additionally, overall detection probabilities declined in detected WNS-impacted species between years. A paired t-test of simultaneous sampling on 21 occasions revealed that overall recorded foraging activity per hour was greater using active than passive sampling for big brown bats and greater using passive than active sampling for little brown bats. There was no significant difference in recorded activity between methods for other WNS-impacted species, presumably because these species have been so reduced in number that their “apparency” on the landscape is lower. Finally, a cost analysis of standard passive and active sampling protocols revealed that passive

  3. MAGNETIC ACTIVITY ANALYSIS FOR A SAMPLE OF G-TYPE MAIN SEQUENCE KEPLER TARGETS

    Energy Technology Data Exchange (ETDEWEB)

    Mehrabi, Ahmad [Department of Physics, Bu Ali Sina University, 65178, 016016, Hamedan (Iran, Islamic Republic of); He, Han [National Astronomical Observatories, Chinese Academy of Sciences, Beijing (China); Khosroshahi, Habib, E-mail: mehrabi@basu.ac.ir [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), 19395-5531, Tehran (Iran, Islamic Republic of)

    2017-01-10

    The variation of a stellar light curve owing to rotational modulation by magnetic features (starspots and faculae) on the star’s surface can be used to investigate the magnetic properties of the host star. In this paper, we use the periodicity and magnitude of the light-curve variation as two proxies to study the stellar magnetic properties for a large sample of G-type main sequence Kepler targets, for which the rotation periods were recently determined. By analyzing the correlation between the two magnetic proxies, it is found that: (1) the two proxies are positively correlated for most of the stars in our sample, and the percentages of negative, zero, and positive correlations are 4.27%, 6.81%, and 88.91%, respectively; (2) negative correlation stars cannot have a large magnitude of light-curve variation; and (3) with the increase of rotation period, the relative number of positive correlation stars decreases and the negative correlation one increases. These results indicate that stars with shorter rotation period tend to have positive correlation between the two proxies, and a good portion of the positive correlation stars have a larger magnitude of light-curve variation (and hence more intense magnetic activities) than negative correlation stars.

  4. Neutron activation analysis of Permian-Triassic boundary layer samples at the Selong Site in China

    International Nuclear Information System (INIS)

    Miyamoto, Y.; Sakamoto, K.; Mingqing, W.

    1997-01-01

    Thirty samples from a limestone stratum across the Permian-Triassic (P-Tr) boundary layer in China were analyzed for 30 elements by instrumental neutron activation analysis, wavelength dispersive X-ray fluorescence and ICP-MS, and also for mineral compositions with a powder X-ray diffractometer. The depth profile was found to indicate a sudden change of elemental and mineral compositions across the P-Tr boundary. Also the profile showed several peaks in elemental concentrations in the lower Permian layered samples as well as in the overlying Triassic strata, which are associated with the change of mineral compositions. Elemental profiles were found to be classified into 4 groups and to give some insights in the geochemical records. Ir is far less abundant (0.1 ppt) compared with that of the K-T boundaries (10 ppb), and the Ir/Co ratio is outside the K-T and Cl chondrite trends. This change of elementary profile is suggestive of the internal causes rather than the external ones such as an asteroid impact for the mass extinction at the P-Tr boundary. (author)

  5. Determination of essential elements in dietetic sample by neutron activation analysis

    International Nuclear Information System (INIS)

    Siquelli, Murilo V.; Maihara, Vera A. Maihara

    2005-01-01

    In the last years there has been an increase of the dietetic product consumption by people who suffer from diabetes, heart disease and by people concerned about having a healthy life as well. Despite the increase of dietetic product presents in the diet of the Brazilian population, the use of these products is still controversial. The analysis of the nutritional composition of these products is becoming important because a great number of people is changing their traditional food by dietetic products. In the literature, there is no information about the inorganic composition, mainly related to the essential elements, in the dietetic products: diet and light . In this study are presented preliminary results of the concentrations of Br, Ca, Cr, Fe, Na and Zn determined by Instrumental Neutron Activation Analysis in aspartame, saccharin and cyclamate sodium , and stevia based sweetener samples. Gelatin samples, diet and light, were also analyzed. Methodology validation was done analyzing NIST reference materials Tea Leaves (INCT-TL-1) and Mixed Polish Herbs (INCT-MPH-2). (author)

  6. BMR in a Brazilian adult probability sample: the Nutrition, Physical Activity and Health Survey.

    Science.gov (United States)

    Anjos, Luiz A; Wahrlich, Vivian; Vasconcellos, Mauricio Tl

    2014-04-01

    To measure BMR in a probability sample of adults from an urban city of Brazil and to compare indirectly measured BMR (BMRi) with BMR predicted from different equations. BMR data were obtained by indirect calorimetry and estimated by different predictive equations (Schofield; Harris and Benedict; Henry and Rees). Anthropometric and body composition measures were also obtained. The Nutrition, Physical Activity and Health Survey (PNAFS), a household survey conducted in Niterói, Rio de Janeiro state, Brazil. Representative sample of 529 adults (aged ≥20 years; 339 females) living in Niterói, Rio de Janeiro state, Brazil. Mean BMRi values were 5839.7 (se 73.9) kJ/d and 4758.1 (se 39.5) kJ/d for men and women, respectively. Predicted BMR by all equations was significantly higher (difference between means and 95% CI did not include zero) than BMRi in both men and women of all ages. Overall bias in BMR (predicted BMR minus BMRi) using the Schofield equations (overestimation of about 20%) was higher than when using the Henry and Rees equations (13% and 16% overestimation for males and females, respectively). The percentage of individuals whose BMR predicted by the Schofield equations fell within 10% of BMRi was very low (7.8% and 14.1% of males nd females, respectively). Current available predictive equations of BMR are not adequate to estimate BMR in Brazilians living in Niterói, Rio de Janeiro, Brazil.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  8. Neutron activation analysis for the optimal sampling and extraction of extractable organohalogens in human hari

    International Nuclear Information System (INIS)

    Zhang, H.; Chai, Z.F.; Sun, H.B.; Xu, H.F.

    2005-01-01

    Many persistent organohalogen compounds such as DDTs and polychlorinated biphenyls have caused seriously environmental pollution problem that now involves all life. It is know that neutron activation analysis (NAA) is a very convenient method for halogen analysis and is also the only method currently available for simultaneously determining organic chlorine, bromine and iodine in one extract. Human hair is a convenient material to evaluate the burden of such compounds in human body and dan be easily collected from people over wide ranges of age, sex, residential areas, eating habits and working environments. To effectively extract organohalogen compounds from human hair, in present work the optimal Soxhelt-extraction time of extractable organohalogen (EOX) and extractable persistent organohalogen (EPOX) from hair of different lengths were studied by NAA. The results indicated that the optimal Soxhelt-extraction time of EOX and EPOX from human hair was 8-11 h, and the highest EOX and EPOX contents were observed in hair powder extract. The concentrations of both EOX and EPOX in different hair sections were in the order of hair powder ≥ 2 mm > 5 mm, which stated that hair samples milled into hair powder or cut into very short sections were not only for homogeneous. hair sample but for the best hair extraction efficiency.

  9. Fatigue studies in compensated bulk lead zirconate titanate

    International Nuclear Information System (INIS)

    Verdier, Cyril; Morrison, Finlay D.; Lupascu, Doru C.; Scott, James F.

    2005-01-01

    Impedance analysis studies were carried out on compensated bulk lead zirconate titanate samples. Fatigue is concomitant with the onset of dielectric loss. This is shown to be dominantly due to an irreversibly modified near-surface layer that can be polished off. The highly compensated nature of these samples minimizes the role of oxygen vacancies

  10. Predictors of body appearance cognitive distraction during sexual activity in a sample of men with ED.

    Science.gov (United States)

    Pascoal, P M; Raposo, C F; Oliveira, L B

    2015-01-01

    Our aim is to scrutinize the extent to which aspects of body dissatisfaction and relationship variables predict body appearance cognitive distraction during sexual activity (BACDSA) in a sample of men diagnosed with ED. A total of 65 heterosexual Portuguese participants with ED completed a survey that included questions on socio-demographic data as well as body-related and relationship measures. We used the Global Body Dissatisfaction (GBD) Subscale of the Body Attitudes Test; a version of the Contour Drawing Rating Scale; a single item on partner's opinion perceived about one's body appearance; the Global Measure of Relationship Satisfaction; and the Inclusion of Other in Self Scale. Open questions assessed focus on specific body parts during sexual activity and relationship length. Hierarchical multiple regression indicated that only GBD was a significant predictor of BACDSA, contrary to the relationship measures that showed no significant predictive effect (R(2) =0.47). Our results support the important role of individual factors on explanatory models of sexual dysfunctions, suggesting that interventions addressing individual factors that affect BACDSA may be of preference.

  11. MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Ichikawa, Kohei; Ueda, Yoshihiro; Terashima, Yuichi; Oyabu, Shinki; Gandhi, Poshak; Nakagawa, Takao; Matsuta, Keiko

    2012-01-01

    We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 μm band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 λ (9, 18 μm) < 45), which is tighter than that with the FIR luminosities at 90 μm. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 μm in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

  12. Method to determine trace elements in water samples by neutron activation analysis

    International Nuclear Information System (INIS)

    Kueppers, G.; Erdtmann, G.

    1981-05-01

    For the determination of trace elements in water by neutron activation analysis irradiation porcedures and chemical separation procedures have been developed. Irradiation in melted quarz glass ampoules in the presence of a platinum wire (for recombination of the oxyhydrogen gas produced by radiolysis) proved successfull with different variants of the irradiation methods, as long irradiation periods without pressure build-up could be achieved. Possible falsifications of the analysis results were investigated in detail (losses by absorption on vessel walls etc.). The irradiated samples can be measured directly with a gamma ray spectrometer and from the radionuclides found the trace element contents may be calculated. More sensitive determinations are possible if the radionuclides are chemically separated. Procedures for removing the matrix activities, for the separation of the radionuclides in groups of elements and for the isolation of single elements have been developed. For especially sensitive determination of some elements selective separation procedures for antimony, cadmium, selenium, mercury and uranium have been developed. The analytical procedures described have been applied to trace element determinations in river water, glacier ice and water solutions from technical processes. (orig./RB) [de

  13. Cadmium determination in biological samples using neutron activation analysis with radiochemical separations

    International Nuclear Information System (INIS)

    Munoz A, Luis; Gras R, Nuri

    2005-01-01

    Chile has 7500 km of coastline on the Southern Pacific ocean,with about 4500 km of continental coastline that contains a variety of different geographical zones.This variety means that there is a great diversity of marine resources such as fish, shellfish and seaweeds. The utilization of these resources has been increasing in recent years making this sector an economically important one. The catch as of May 2002 came to 1.9 million tons and exports of the different species amounted to US$611.5 million as of April.But this important economic resource is being threatened by the technical demands imposed by importing countries, mainly the specific requirements for sanitary certification for fishery export products, depending on the markets of destination. The chemical element cadmium is one of the most strictly controlled elements due some shellfish accumulate a large amount of this element and to its high toxicity. The Chilean standard's analytical procedures for cadmium determination in hydro biological products, which must be met by laboratories that certify and control these products for export, are now being evaluated. Through its Chemical Metrology Unit, the Chilean Nuclear Energy Commission is strongly supporting this sector by preparing the secondary reference or control materials, and it has developed and implemented nuclear analytical methods for the certification of these materials, which will be used mostly in collaborative studies. This work describes the methodology developed for the determination of cadmium in biological samples, particularly in shellfish and fish. The method is based on neutron activation analysis with radiochemical separations, using the radioisotopes 115 Cd and 115m In, generated in the samples by bombarding with neutrons in a nuclear reactor. The samples were digested at 110 o C with H 2 SO 4 and H 2 O 2 and then the radioactive cadmium element was separated from the other elements present in the samples using a Bio Rad AG 2-X8

  14. Identification of cadmium in biological samples using neutron activation analysis with radiochemistry separations

    International Nuclear Information System (INIS)

    Munoz A, Luis; Gras R, Nuri

    2002-01-01

    Chile's 7500 km coastline of the Southern Pacific ocean, with about 4500 km of continental coastline that contains a variety of different geographical zones. This variety means that there is a great diversity of marine resources such as fish, shellfish and seaweeds. The utilization of these resources has been increasing in recent years making this sector an economically important one. The catch as of May 2002 came to 1.9 million tons and exports of the different species amounted to US$611.5 million as of April. But this important economic resource is being threatened by the technical demands imposed by importing countries, mainly the specific requirements for sanitary certification for fishery export products, depending on the markets of destination. The chemical element cadmium is one of the most strictly controlled elements due some shellfish accumulate a large amount of this element and to its high toxicity. The Chilean standard's analytical procedures for cadmium determination in hydro biological products, which must be met by laboratories that certify and control these products for export, are now being evaluated. Through its Chemical Metrology Unit, the Chilean Nuclear Energy Commission is strongly supporting this sector by preparing the secondary reference or control materials, and it has developed and implemented nuclear analytical methods for the certification of these materials, which will be used mostly in collaborative studies. This work describes the methodology developed for the determination of cadmium in biological samples, particularly in shellfish and fish. The method is based on neutron activation analysis with radiochemical separations, using the radioisotopes 115 Cd and 115m In, generated in the samples by bombarding with neutrons in a nuclear reactor. The samples were digested at 110 o C with H 2 SO 4 and H 2 O 2 and then the radioactive cadmium element was separated from the other elements present in the samples using a Bio Rad AG 2-X8 resin

  15. Psychometrics of the preschooler physical activity parenting practices instrument among a Latino sample.

    Science.gov (United States)

    O'Connor, Teresia M; Cerin, Ester; Hughes, Sheryl O; Robles, Jessica; Thompson, Deborah I; Mendoza, Jason A; Baranowski, Tom; Lee, Rebecca E

    2014-01-15

    Latino preschoolers (3-5 year old children) have among the highest rates of obesity. Low levels of physical activity (PA) are a risk factor for obesity. Characterizing what Latino parents do to encourage or discourage their preschooler to be physically active can help inform interventions to increase their PA. The objective was therefore to develop and assess the psychometrics of a new instrument: the Preschooler Physical Activity Parenting Practices (PPAPP) among a Latino sample, to assess parenting practices used to encourage or discourage PA among preschool-aged children. Cross-sectional study of 240 Latino parents who reported the frequency of using PA parenting practices. 95% of respondents were mothers; 42% had more than a high school education. Child mean age was 4.5 (±0.9) years (52% male). Test-retest reliability was assessed in 20%, 2 weeks later. We assessed the fit of a priori models using Confirmatory factor analyses (CFA). In a separate sub-sample (35%), preschool-aged children wore accelerometers to assess associations with their PA and PPAPP subscales. The a-priori models showed poor fit to the data. A modified factor structure for encouraging PPAPP had one multiple-item scale: engagement (15 items), and two single-items (have outdoor toys; not enroll in sport-reverse coded). The final factor structure for discouraging PPAPP had 4 subscales: promote inactive transport (3 items), promote screen time (3 items), psychological control (4 items) and restricting for safety (4 items). Test-retest reliability (ICC) for the two scales ranged from 0.56-0.85. Cronbach's alphas ranged from 0.5-0.9. Several sub-factors correlated in the expected direction with children's objectively measured PA. The final models for encouraging and discouraging PPAPP had moderate to good fit, with moderate to excellent test-retest reliabilities. The PPAPP should be further evaluated to better assess its associations with children's PA and offers a new tool for measuring PPAPP

  16. Zirconium based bulk metallic glasses

    International Nuclear Information System (INIS)

    Dey, G.K.; Neogy, S.; Savalia, R.T.; Tewari, R.; Srivastava, D.; Banerjee, S.

    2006-01-01

    Metallic glasses have come into prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. In this study, bulk glasses have been obtained in Zr based multicomponent alloy by induction melting these alloys in silica crucibles and casting these in form of rods 3 and 6 mm in diameter in a copper mould

  17. Longitudinal bulk acoustic mass sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Teva, Jordi; Boisen, Anja

    2009-01-01

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10(-15) g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise...

  18. Bulk viscosity of molecular fluids

    Science.gov (United States)

    Jaeger, Frederike; Matar, Omar K.; Müller, Erich A.

    2018-05-01

    The bulk viscosity of molecular models of gases and liquids is determined by molecular simulations as a combination of a dilute gas contribution, arising due to the relaxation of internal degrees of freedom, and a configurational contribution, due to the presence of intermolecular interactions. The dilute gas contribution is evaluated using experimental data for the relaxation times of vibrational and rotational degrees of freedom. The configurational part is calculated using Green-Kubo relations for the fluctuations of the pressure tensor obtained from equilibrium microcanonical molecular dynamics simulations. As a benchmark, the Lennard-Jones fluid is studied. Both atomistic and coarse-grained force fields for water, CO2, and n-decane are considered and tested for their accuracy, and where possible, compared to experimental data. The dilute gas contribution to the bulk viscosity is seen to be significant only in the cases when intramolecular relaxation times are in the μs range, and for low vibrational wave numbers (<1000 cm-1); This explains the abnormally high values of bulk viscosity reported for CO2. In all other cases studied, the dilute gas contribution is negligible and the configurational contribution dominates the overall behavior. In particular, the configurational term is responsible for the enhancement of the bulk viscosity near the critical point.

  19. Spatio-temporal foreshock activity during stick-slip experiments of large rock samples

    Science.gov (United States)

    Tsujimura, Y.; Kawakata, H.; Fukuyama, E.; Yamashita, F.; Xu, S.; Mizoguchi, K.; Takizawa, S.; Hirano, S.

    2016-12-01

    Foreshock activity has sometimes been reported for large earthquakes, and has been roughly classified into the following two classes. For shallow intraplate earthquakes, foreshocks occurred in the vicinity of the mainshock hypocenter (e.g., Doi and Kawakata, 2012; 2013). And for intraplate subduction earthquakes, foreshock hypocenters migrated toward the mainshock hypocenter (Kato, et al., 2012; Yagi et al., 2014). To understand how foreshocks occur, it is useful to investigate the spatio-temporal activities of foreshocks in the laboratory experiments under controlled conditions. We have conducted stick-slip experiments by using a large-scale biaxial friction apparatus at NIED in Japan (e.g., Fukuyama et al., 2014). Our previous results showed that stick-slip events repeatedly occurred in a run, but only those later events were preceded by foreshocks. Kawakata et al. (2014) inferred that the gouge generated during the run was an important key for foreshock occurrence. In this study, we proceeded to carry out stick-slip experiments of large rock samples whose interface (fault plane) is 1.5 meter long and 0.5 meter wide. After some runs to generate fault gouge between the interface. In the current experiments, we investigated spatio-temporal activities of foreshocks. We detected foreshocks from waveform records of 3D array of piezo-electric sensors. Our new results showed that more than three foreshocks (typically about twenty) had occurred during each stick-slip event, in contrast to the few foreshocks observed during previous experiments without pre-existing gouge. Next, we estimated the hypocenter locations of the stick-slip events, and found that they were located near the opposite end to the loading point. In addition, we observed a migration of foreshock hypocenters toward the hypocenter of each stick-slip event. This suggests that the foreshock activity observed in our current experiments was similar to that for the interplate earthquakes in terms of the

  20. Accounting for medical variation: the case of prescribing activity in a New Zealand general practice sample.

    Science.gov (United States)

    Davis, P B; Yee, R L; Millar, J

    1994-08-01

    Medical practice variation is extensive and well documented, particularly for surgical interventions, and raises important questions for health policy. To date, however, little work has been carried out on interpractitioner variation in prescribing activity in the primary care setting. An analytical model of medical variation is derived from the literature and relevant indicators are identified from a study of New Zealand general practice. The data are based on nearly 9,500 completed patient encounter records drawn from over a hundred practitioners in the Waikato region of the North Island, New Zealand. The data set represents a 1% sample of all weekday general practice office encounters in the Hamilton Health District recorded over a 12-month period. Overall levels of prescribing, and the distribution of drug mentions across diagnostic groupings, are broadly comparable to results drawn from international benchmark data. A multivariate analysis is carried out on seven measures of activity in the areas of prescribing volume, script detail, and therapeutic choice. The analysis indicates that patient, practitioner and practice attributes exert little systematic influence on the prescribing task. The principal influences are diagnosis, followed by practitioner identity. The pattern of findings suggests also that the prescribing task cannot be viewed as an undifferentiated activity. It is more usefully considered as a process of decision-making in which 'core' judgements--such as the decision to prescribe and the choice of drug--are highly predictable and strongly influenced by diagnosis, while 'peripheral' features of the task--such as choosing a combination drug or prescribing generically--are less determinate and more subject to the exercise of clinical discretion.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Risk of acute gout among active smokers: data from nationwide inpatient sample.

    Science.gov (United States)

    Poudel, Dilli Ram; Karmacharya, Paras; Donato, Anthony

    2016-12-01

    Smoking has been found to be negatively correlated with serum uric acid levels by virtue of reduced production and increased consumption of endogenous antioxidant uric acid among smokers and has been reported to decrease incidence of gout. To shed further light on the question of association between active smoking and acute gout by examining this association using a large inpatient US database, using the Nationwide Inpatient Sample data from 2009 to 2011, we identified current smokers based on the International Classification of Diseases, Ninth Revision (ICD-9) code 305.1 and were assumed to have ceased smoking during hospital stay. Patients who developed acute gout inhospital were identified based on ICD-9 code 274.01 at secondary diagnosis position. Univariate and multivariate logistic regressions were used to derive odds ratio for measures of association. Statistical analysis was done using STATA version 13.0 (College Station, TX). A total of 17,847,045 discharge records were used which included 13,932 (0.08 %) inhospital acute gouty arthritis and 2,615,944 (14.66 %) active smokers. Both univariate (OR 0.59, CI 0.54-0.63, p gout among hospitalized patients who were current smokers but were assumed to have ceased smoking during hospital stay. Active tobacco use was associated with a lower risk of acute inpatient gouty arthritis, even when controlling for conventional risk factors. More study is needed to correlate this finding with uric acid levels, and a better understanding of the mechanisms that explain this finding are necessary.

  2. Methodological interference of biochar in the determination of extracellular enzyme activities in composting samples

    Science.gov (United States)

    Jindo, K.; Matsumoto, K.; García Izquierdo, C.; Sonoki, T.; Sanchez-Monedero, M. A.

    2014-07-01

    Biochar application has received increasing attention as a means to trap recalcitrant carbon and enhance soil fertility. Hydrolytic enzymatic assays, such as β-glucosidase and phosphatase activities, are used for the assessment of soil quality and composting process, which are based on use of p-nitrophenol (PNP) derivatives as substrate. However, sorption capacity of biochar can interfere with colorimetric determination of the hydrolysed PNP, either by the sorption of the substrate or the reaction product of hydrolysis into biochar surface. The aim of the present work is to study the biochar sorption capacity for PNP in biochar-blended composting mixtures in order to assess its impact on the estimation of the colorimetric-based enzymatic assays. A retention test was conducted by adding a solution of known amounts of PNP in universal buffer solution (pH = 5, 6.5 and 11, corresponding to the β-glucosidase, acid and alkaline phosphatase activity assays, respectively), in samples taken at the initial stage and after maturation stage from four different composting piles (two manure composting piles; PM: poultry manure, CM: cow manure and two other similar piles containing 10% of additional biochar (PM + B, CM + B)). The results show that biochar-blended composts (PM + B, CM + B) generally exhibited low enzymatic activities, compared to manure compost without biochar (PM, CM). In terms of the difference between the initial and maturation stage of composting process, the PNP retention in biochar was shown higher at maturation stage, caused most probably by an enlarged proportion of biochar inside compost mixture after the selective degradation of easily decomposable organic matter. TThe retention of PNP on biochar was influenced by pH dependency of sorption capacity of biochar and/or PNP solubility, since PNP was more efficiently retained by biochar at low pH values (5 and 6.5) than at high pH values (11).

  3. Perovskite oxides: Oxygen electrocatalysis and bulk structure

    Science.gov (United States)

    Carbonio, R. E.; Fierro, C.; Tryk, D.; Scherson, D.; Yeager, Ernest

    1987-01-01

    Perovskite type oxides were considered for use as oxygen reduction and generation electrocatalysts in alkaline electrolytes. Perovskite stability and electrocatalytic activity are studied along with possible relationships of the latter with the bulk solid state properties. A series of compounds of the type LaFe(x)Ni1(-x)O3 was used as a model system to gain information on the possible relationships between surface catalytic activity and bulk structure. Hydrogen peroxide decomposition rate constants were measured for these compounds. Ex situ Mossbauer effect spectroscopy (MES), and magnetic susceptibility measurements were used to study the solid state properties. X ray photoelectron spectroscopy (XPS) was used to examine the surface. MES has indicated the presence of a paramagnetic to magnetically ordered phase transition for values of x between 0.4 and 0.5. A correlation was found between the values of the MES isomer shift and the catalytic activity for peroxide decomposition. Thus, the catalytic activity can be correlated to the d-electron density for the transition metal cations.

  4. Photocarrier dynamics in monolayer phosphorene and bulk black phosphorus.

    Science.gov (United States)

    Zereshki, Peymon; Wei, Yaqing; Ceballos, Frank; Bellus, Matthew Z; Lane, Samuel D; Pan, Shudi; Long, Run; Zhao, Hui

    2018-06-13

    We report a combined theoretical and experimental study on photocarrier dynamics in monolayer phosphorene and bulk black phosphorus. Samples of monolayer phosphorene and bulk black phosphorus were fabricated by mechanical exfoliation, identified according to their reflective contrasts, and protected by covering them with hexagonal boron nitride layers. Photocarrier dynamics in these samples was studied by an ultrafast pump-probe technique. The photocarrier lifetime of monolayer phosphorene was found to be about 700 ps, which is about 9 times longer than that of bulk black phosphorus. This trend was reproduced in our calculations based on ab initio nonadiabatic molecular dynamics combined with time-domain density functional theory in the Kohn-Sham representation, and can be attributed to the smaller bandgap and stronger nonadiabatic coupling in bulk. The transient absorption response was also found to be dependent on the sample orientation with respect to the pump polarization, which is consistent with the previously reported anisotropic absorption of phosphorene. In addition, an oscillating component of the differential reflection signal at early probe delays was observed in the bulk sample and was attributed to the layer-breathing phonon mode with an energy of about 1 meV and a decay time of about 1.35 ps. These results provide valuable information for application of monolayer phosphorene in optoelectronics.

  5. New methodological approaches to the simultaneous measurement of the 90Sr and 137Cs activity in environmental samples

    Directory of Open Access Journals (Sweden)

    M. V. Zheltonozhska

    2012-12-01

    Full Text Available Nonradiochemical method of measurement of 90Sr and137Cs activity in environmental samples is proposed. This method is based on spectrometrical investigation of electrons accompanied the decay of the 90Sr and137Cs. Accounting for the contribution to the total activity of the samples from the zones with the density of the contamination 1 - 5 Кu/km2 the 40K electrons allowed to improve the accuracy of the measurements for the samples of small rodents up to 15 - 20 % (the ratio of A (137Cs/A (90Sr was from 2 to 100, for samples of soil up to 10 - 15 % (the change of activity in these samples was ten thousand times. The results of the spectrometric measurements were confirmed by the traditional radiochemical research.

  6. ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J. [Astronomy Department, University of California, Berkeley, CA 94720-7450 (United States); Brink, Henrik [Dark Cosmology Centre, Juliane Maries Vej 30, 2100 Copenhagen O (Denmark); Long, James P.; Rice, John, E-mail: jwrichar@stat.berkeley.edu [Statistics Department, University of California, Berkeley, CA 94720-7450 (United States)

    2012-01-10

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL-where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up-is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  7. Evaluation of precision and accuracy of neutron activation analysis method of environmental samples analysis

    International Nuclear Information System (INIS)

    Wardani, Sri; Rina M, Th.; L, Dyah

    2000-01-01

    Evaluation of precision and accuracy of Neutron Activation Analysis (NAA) method used by P2TRR performed by analyzed the standard reference samples from the National Institute of Environmental Study of Japan (NIES-CRM No.10 (rice flour) and the National Bureau of USA (NBS-SRM 1573a (tomato leave) by NAA method. In analyze the environmental SRM No.10 by NAA method in qualitatively could identified multi elements of contents, namely: Br, Ca, Co, CI, Cs, Gd, I, K< La, Mg, Mn, Na, Pa, Sb, Sm, Sr, Ta, Th, and Zn (19 elements) for SRM 1573a; As, Br, Cr, CI, Ce, Co, Cs, Fe, Ga, Hg, K, Mn, Mg, Mo, Na, Ni, Pb, Rb, Sr, Se, Sc, Sb, Ti, and Zn, (25 elements) for CRM No.10a; Ag, As, Br, Cr, CI, Ce, Cd, Co, Cs, Eu, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Pb, Rb, Sb, Sc, Th, TI, and Zn, (26 elements) for CRM No. 10b; As, Br, Co, CI, Ce, Cd, Ga, Hg, K, Mn, Mg, Mo, Na, Nb, Pb, Rb, Sb, Se, TI, and Zn (20 elementary) for CRM No.10c. In the quantitatively analysis could determined only some element of sample contents, namely: As, Co, Cd, Mo, Mn, and Zn. From the result compared with NIES or NBS values attained with deviation of 3% ∼ 15%. Overall, the result shown that the method and facilities have a good capability, but the irradiation facility and the software of spectrometry gamma ray necessary to developing or seriously research perform

  8. ACTIVE LEARNING TO OVERCOME SAMPLE SELECTION BIAS: APPLICATION TO PHOTOMETRIC VARIABLE STAR CLASSIFICATION

    International Nuclear Information System (INIS)

    Richards, Joseph W.; Starr, Dan L.; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; Berian James, J.; Brink, Henrik; Long, James P.; Rice, John

    2012-01-01

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  9. Measurement of activity concentration of primordial radionuclides in the soil samples of Tiruchirappalli, Tamil Nadu, India

    International Nuclear Information System (INIS)

    Sadiq Bukhari, A.; Saiyad Musthafa, M.; Syed Mohamed, H.E.; Krishnamoorthy, R.; Shahul Hameed, M.M.; Shahul Hameed, P.

    2008-01-01

    Full text: Radioactive minerals such as uranium ( 238 U), thorium ( 232 Th) and potassium ( 40 K) are considered to be Primordial radionuclides which are widely distributed in the earth's crust. Gamma-radiation from these radionuclides represents the main external source of irradiation for the human body. Human beings are exposed outdoors to the natural terrestrial radiation that originates predominantly from the upper 30 cm of the soil. A pilot project was therefore initiated aiming at systematically measuring the terrestrial gamma radiation in Tiruchirappalli city, Tamil Nadu, South India and to establish baseline data on the terrestrial background radiation level determining its contribution to the annual effective dose equivalent to the human population. The natural radioactivity concentrations were studied in soil samples collected from 50 locations in Tiruchirappalli city. The concentration varies significantly over different soil types and the highest radioactivity was measured over soil types of granite origin followed by red soil and alluvial loam. The mean activity concentrations of 232 Th, 238 U and 40 K in soil samples are found to be 81.78 Bq.kg -1 , 32.62 Bq.kg -1 , and 551.35 Bq.kg -1 respectively. The calculated gamma dose from the soil is in the range between 38.86nGy.h -1 and 240.59 nGy.h -1 with a mean value of 89.76 nGy.h -1 . The mean annual effective dose to the population from outdoor terrestrial gamma radiation was estimated to be 0.11mSv.y -1 which is low as compared with the maximum permissible effective dose equivalent of 1mSv.y -1 (ICRP,1991). In the present study it is observed that the major sources of gamma radiation in soils are mainly derived from rocky area with granite basement. (author)

  10. DISSECTING PHOTOMETRIC REDSHIFT FOR ACTIVE GALACTIC NUCLEUS USING XMM- AND CHANDRA-COSMOS SAMPLES

    International Nuclear Information System (INIS)

    Salvato, M.; Hasinger, G.; Ilbert, O.; Rau, A.; Brusa, M.; Bongiorno, A.; Civano, F.; Elvis, M.; Zamorani, G.; Vignali, C.; Comastri, A.; Bardelli, S.; Bolzonella, M.; Cappelluti, N.; Aussel, H.; Le Floc'h, E.; Fiore, F.; Mainieri, V.; Capak, P.; Caputi, K.

    2011-01-01

    In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results presently available for normal galaxies. We demonstrate that morphologically extended, faint X-ray sources without optical variability are more accurately described by a library of normal galaxies (corrected for emission lines) than by active galactic nucleus (AGN) dominated templates, even if these sources have AGN-like X-ray luminosities. Preselecting the library on the bases of the source properties allowed us to reach an accuracy σ Δz/(1+z spec ) ∼0.015 with a fraction of outliers of 5.8% for the entire Chandra-COSMOS sample. In addition, we release revised photometric redshifts for the 1735 optical counterparts of the XMM-detected sources over the entire 2 deg 2 of COSMOS. For 248 sources, our updated photometric redshift differs from the previous release by Δz > 0.2. These changes are predominantly due to the inclusion of newly available deep H-band photometry (H AB = 24 mag). We illustrate once again the importance of a spectroscopic training sample and how an assumption about the nature of a source together, with the number and the depth of the available bands, influences the accuracy of the photometric redshifts determined for AGN. These considerations should be kept in mind when defining the observational strategies of upcoming large surveys targeting AGNs, such as eROSITA at X-ray energies and the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe in the radio band.

  11. Active Learning to Overcome Sample Selection Bias: Application to Photometric Variable Star Classification

    Science.gov (United States)

    Richards, Joseph W.; Starr, Dan L.; Brink, Henrik; Miller, Adam A.; Bloom, Joshua S.; Butler, Nathaniel R.; James, J. Berian; Long, James P.; Rice, John

    2012-01-01

    Despite the great promise of machine-learning algorithms to classify and predict astrophysical parameters for the vast numbers of astrophysical sources and transients observed in large-scale surveys, the peculiarities of the training data often manifest as strongly biased predictions on the data of interest. Typically, training sets are derived from historical surveys of brighter, more nearby objects than those from more extensive, deeper surveys (testing data). This sample selection bias can cause catastrophic errors in predictions on the testing data because (1) standard assumptions for machine-learned model selection procedures break down and (2) dense regions of testing space might be completely devoid of training data. We explore possible remedies to sample selection bias, including importance weighting, co-training, and active learning (AL). We argue that AL—where the data whose inclusion in the training set would most improve predictions on the testing set are queried for manual follow-up—is an effective approach and is appropriate for many astronomical applications. For a variable star classification problem on a well-studied set of stars from Hipparcos and Optical Gravitational Lensing Experiment, AL is the optimal method in terms of error rate on the testing data, beating the off-the-shelf classifier by 3.4% and the other proposed methods by at least 3.0%. To aid with manual labeling of variable stars, we developed a Web interface which allows for easy light curve visualization and querying of external databases. Finally, we apply AL to classify variable stars in the All Sky Automated Survey, finding dramatic improvement in our agreement with the ASAS Catalog of Variable Stars, from 65.5% to 79.5%, and a significant increase in the classifier's average confidence for the testing set, from 14.6% to 42.9%, after a few AL iterations.

  12. Detecting estrogenic activity in water samples withestrogen-sensitive yeast cells using spectrophotometry and fluorescencemicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wozei, E.; Holman, H-Y.N.; Hermanowicz, S.W.; Borglin S.

    2006-03-15

    Environmental estrogens are environmental contaminants that can mimic the biological activities of the female hormone estrogen in the endocrine system, i.e. they act as endocrine disrupters. Several substances are reported to have estrogen-like activity or estrogenic activity. These include steroid hormones, synthetic estrogens (xenoestrogens), environmental pollutants and phytoestrogens (plant estrogens). Using the chromogenic substrate ortho-nitrophenyl-{beta}-D-galactopyranoside (ONPG) we show that an estrogen-sensitive yeast strain RMY/ER-ERE, with human estrogen receptor (hER{alpha}) gene and the lacZ gene which encodes the enzyme {beta}-galactosidase, is able to detect estrogenic activity in water samples over a wide range of spiked concentrations of the hormonal estrogen 17{beta}-estradiol (E2). Ortho-nitrophenol (ONP), the yellow product of this assay can be detected using spectrophotometry but requires cell lysis to release the enzyme and allow product formation. We improved this aspect in a fluorogenic assay by using fluorescein di-{beta}-D-galactopyranoside (FDG) as a substrate. The product was visualized using fluorescence microscopy without the need to kill, fix or lyse the cells. We show that in live yeast cells, the uptake of E2 and the subsequent production of {beta}-galactosidase enzyme occur quite rapidly, with maximum enzyme-catalyzed fluorescent product formation evident after about 30 minutes of exposure to E2. The fluorogenic assay was applied to a selection of estrogenic compounds and the Synchrotron-based Fourier transform infrared (SR-FTIR) spectra of the cells obtained to better understand the yeast whole cell response to the compounds. The fluorogenic assay is most sensitive to E2, but the SR-FTIR spectra suggest that the cells respond to all the estrogenic compounds tested even when no fluorescent response was detected. These findings are promising and may shorten the duration of environmental water screening and monitoring regimes using

  13. Novel sampling methods for atmospheric semi-volatile organic compounds (SOCs) in a high altitude alpine environment

    Energy Technology Data Exchange (ETDEWEB)

    Offenthaler, I. [Umweltbundesamt GmbH (Austria); Jakobi, G. [Helmholtz Zentrum Muenchen (German Research Centre for Environmental Health) (Germany); Kaiser, A. [ZAMG-Zentralanstalt fuer Meteorologie und Geo-dynamik (Austria); Kirchner, M. [Helmholtz Zentrum Muenchen (German Research Centre for Environmental Health) (Germany); Kraeuchi, N. [WSL-Swiss Federal Institute for Forest, Snow and Landscape Research (Switzerland); Niedermoser, B. [ZAMG-Zentralanstalt fuer Meteorologie und Geo-dynamik (Austria); Schramm, K.-W. [Helmholtz Zentrum Muenchen (German Research Centre for Environmental Health) (Germany); Sedivy, I. [WSL-Swiss Federal Institute for Forest, Snow and Landscape Research (Switzerland); Staudinger, M. [ZAMG-Zentralanstalt fuer Meteorologie und Geo-dynamik (Austria); Thanner, G.; Weiss, P. [Umweltbundesamt GmbH (Austria); Moche, W., E-mail: wolfgang.moche@umweltbundesamt.a [Umweltbundesamt GmbH (Austria)

    2009-12-15

    High- and low-volume active air samplers as well as bulk deposition samplers were developed to sample atmospheric SOCs under the adverse conditions of a mountain environment. Active sampling employed separate filters for different European source regions. Filters were switched depending on daily trajectory forecasts, whose accuracy was evaluated post hoc. The sampling continued on three alpine summits over five periods of four months. The prevailing trajectories varied stronger between sampling periods than between stations. The sampling equipment (active and bulk deposition) proved dependable for operation in a mountain environment, with idle times being mainly due to non-routine manipulations and connectivity. - Equipment for direction-specific air sampling and bulk deposition sampling in mountains was developed and tested.

  14. Measurement of radionuclide activities of uranium-238 series in soil samples by gamma spectrometry: case of Vinaninkarena

    International Nuclear Information System (INIS)

    Randrianantenaina, F.R.

    2017-01-01

    The aim of this work is to determine the activity level of radionuclides of uranium-238 series. Eight soil samples are collected at Rural Commune of Vinaninkarena. After obtaining secular equilibrium, these samples have been measured using gamma spectrometry system in the Nuclear Analyses and Techniques Department of INSTN-Madagascar, with HPGe detector (30 % relative efficiency) and a Genie 2000 software. Activities obtained vary from (78±2)Bq.kg -1 to (49 231 ± 415)Bq.kg -1 . Among these eight samples, three activity levels are shown. Low activity is an activity which has value lower or equal to (89±3)Bq.kg -1 . Average activity is an activity which has value between (186± 1)Bq.kg -1 and (1049 ±7)Bq.kg -1 . And high activity is an activity which has value higher or equal to (14501±209)Bq.kg -1 . According to UNSCEAR 2000, these value are all higher than the world average value which is 35 Bq.kg -1 .It is due to the localities of sampling points. The variation of the activity level depends on radionuclide concentration of uranium-238 series in the soil. [fr

  15. Sampling and analysis plan for the preoperational environmental survey for the immobilized low activity waste (ILAW) project W-465

    International Nuclear Information System (INIS)

    Mitchell, R.M.

    1998-01-01

    This document provides a detailed description of the Sampling and Analysis Plan for the Preoperational Survey to be conducted at the Immobilized Low Activity Waste (ILAW) Project Site in the 200 East Area

  16. Determination of organic fluorine in aqueous samples with neutron activation analysis in comparison with the DIN method

    Energy Technology Data Exchange (ETDEWEB)

    Rollinger, D. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55099 Mainz (Germany); Kratz, K.L. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55099 Mainz (Germany)

    1996-04-01

    Neutron activation analysis (NAA) has been used as detection technique for adsorbable organic fluorine in aqueous samples. The results have been compared with the standardized DIN method which uses a fluoride-ion-selective electrode (ISE). (orig.). With 3 tabs.

  17. PRE-CONCENTRATION AND DETERMINATION OF HEAVY METALS ON MODIFIED ACTIVATED CARBON IN REAL SAMPLES

    Directory of Open Access Journals (Sweden)

    F. Ahmadi

    2010-06-01

    Full Text Available A sensitive and simple method for the simultaneous pre-concentration of nutritionally important minerals in real samples has been reported. The method is based on the formation of metal complexes by N, N'-diacetyl-4-bromo-2, 6-di (aminomethyl phenol (DBDP loaded on activated carbon. The metals content on the complexes are then eluted using 6mL 4M HNO3, which are detected by AAS at resonance line. In this procedure, minerals such as Ni, Cu, Co, Pb Zn and Cd can be analyzed in one run by caring out the simultaneous separation and quantification of them. At optimum condition the response are linear over concentration range of for 0.03-1.1 µg mL-1 for Ni2+ , 0.03-1.0 µg mL-1 for Cu2+, 0.02-1.0 µg mL-1 for  Pb2+ , 0.02-1.0 µg mL-1 for  Co2+,0.02-1.1 µg mL-1 Zn2+ and 0.05-1.3 µg mL-1for Cd2+. The detection limits of each element are expressed as the amount of analytes in µg mL-1 giving a signal to noise ratio of 3 are equal to 2.5, 2.4, 1.6, 2.4, 1.9 and 2.1 for Ni2+ , Cu2+, Pb2+ , Co2+,Zn2+ and Cd2+. The ability of method for repeatable recovery of trace ion are 99.9, 98.7, 99.2 , 98.7, 98.5and 95.6 with R.S.D of 1.3, 1.4, 1.2, 1.4, 1.7 and 1.4 for Ni2+ , Cu2+, Pb2+ , Co2+,Zn2+ and Cd2+. The method has been successfully applied for these metals content evaluation in some real samples including natural water and vegetable.     Keywords: Heavy Metals, N, N'-diacetyl-4-bromo-2,6-di(aminomethyl phenol (DBDP, Activated Carbon

  18. The influence of the self-absorption on the measure of the total alpha activity in water samples

    International Nuclear Information System (INIS)

    Acena, M.L.; Gonzalez, J.A.; De Pablo, A.

    1981-01-01

    The self-absorption is an important difficulty in measuring α-activities in river water samples. A semiempirical equation for calculating the self-absorption versus sample thickness has been obtained. This equation is valid for the regular saline residues in spanish rivers and for thicknesses lower than 2 mg x cm -2 . This figure sets a limit for the amount of water to be evaporated from the sample. (author)

  19. The development of an automatic sample-changer and control instrumentation for isotope-source neutron-activation analysis

    International Nuclear Information System (INIS)

    Andeweg, A.H.; Watterson, J.I.W.

    1983-01-01

    An automatic sample-changer was developed at the Council for Mineral Technology for use in isotope-source neutron-activation analysis. Tests show that the sample-changer can transfer a sample of up to 3 kg in mass over a distance of 3 m within 5 s. In addition, instrumentation in the form of a three-stage sequential timer was developed to control the sequence of irradiation transfer and analysis

  20. Bulk Vitrification Castable Refractory Block Protection Study

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.; Bagaasen, Larry M.; Beck, Andrew E.; Brouns, Thomas M.; Caldwell, Dustin D.; Elliott, Michael L.; Matyas, Josef; Minister, Kevin BC; Schweiger, Michael J.; Strachan, Denis M.; Tinsley, Bronnie P.; Hollenberg, Glenn W.

    2005-05-01

    Bulk vitrification (BV) was selected for a pilot-scale test and demonstration facility for supplemental treatment to accelerate the cleanup of low-activity waste (LAW) at the Hanford U.S. DOE Site. During engineering-scale (ES) tests, a small fraction of radioactive Tc (and Re, its nonradioactive surrogate) were transferred out of the LAW glass feed and molten LAW glass, and deposited on the surface and within the pores of the castable refractory block (CRB). Laboratory experiments were undertaken to understand the mechanisms of the transport Tc/Re into the CRB during vitrification and to evaluate various means of CRB protection against the deposition of leachable Tc/Re. The tests used Re as a chemical surrogate for Tc. The tests with the baseline CRB showed that the molten LAW penetrates into CRB pores before it converts to glass, leaving deposits of sulfates and chlorides when the nitrate components decompose. Na2O from the LAW reacts with the CRB to create a durable glass phase that may contain Tc/Re. Limited data from a single CRB sample taken from an ES experiment indicate that, while a fraction of Tc/Re is present in the CRB in a readily leachable form, most of the Tc/Re deposited in the refractory is retained in the form of a durable glass phase. In addition, the molten salts from the LAW, mainly sulfates, chlorides, and nitrates, begin to evaporate from BV feeds at temperatures below 800 C and condense on solid surfaces at temperatures below 530 C. Three approaches aimed at reducing or preventing the deposition of soluble Tc/Re within the CRB were proposed: metal lining, sealing the CRB surface with a glaze, and lining the CRB with ceramic tiles. Metal liners were deemed unsuitable because evaluations showed that they can cause unacceptable distortions of the electric field in the BV system. Sodium silicate and a low-alkali borosilicate glaze were selected for testing. The glazes slowed down molten salt condensate penetration, but did little to reduce the