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Sample records for 10be concentration measurements

  1. 10Be concentrations in recent firn and ice from Law Dome Antarctica

    Full text: ANSTO has been collaborating with the AAD Glaciology Program and CSIRO Atmospheric Research over the last six years on the measurement of cosmogenic isotopes from Law Dome ice sheet, East Antarctica. In this paper we present our first result s of 10Be concentrations measured in the ice and firn from samples spanning this century and taken from three cores with up to a seven-fold variation in accumulation rate. In combination with a well established ice chronology, this has enabled a study of the relationship between the snow accumulation rate and the measured 10Be concentration. Preliminary results suggest that, for Law Dome, the 10 Be concentration is independent of accumulation rate and that most 10Be is incorporated into the ice sheet as a result of 'wet' precipitation. Questions concerning the degree to which 10Be is adsorbed on dust particles or present as a soluble form have complicated the interpretation of the 10Be record in Northern Hemisphere ice cores. To better understand the implications for Law Dome ice we have undertaken two pilot experiments. One experiment involved measurement of the short lived radioisotope 7Be along with 10Be in surface snow samples in an attempt to elucidate transport effects. The second experiment was aimed at determination of the partitioning of 10Be among terrestrial dust particles of different

  2. 41Ca, 14C and 10Be concentrations in coral sand from the Bikini atoll

    Activation measurements of materials exposed to nuclear bomb explosions are widely used to reconstruct the neutron flux for retrospective dosimetry. In this study the applicability of coral CaCO3 as a biogenic neutron fluence dosimeter is tested. The long-lived radioisotopes 41Ca, 14C and 10Be, which had been produced in nuclear bomb explosions, are measured in several coral sand samples from the Bikini atoll at the 600 kV and 200 kV AMS facilities of ETH Zurich. Elevated concentrations of all studied isotopes are found in a sample from the crater that was initially formed by the high-yield nuclear explosion Castle Bravo in 1954 and that had been used as site for several tests afterward. The observed 14C concentration is considered too large to originate from neutron irradiation of CaCO3 alone. The relatively low concentration of 10Be found in the crater sample indicates that production of 10Be during nuclear bomb testing is generally minor. A simple neutron fluence reconstruction is performed on basis of the 41Ca/40Ca ratio. - Highlights: • Concentrations of 41Ca, 14C and 10Be were determined at the Bikini atoll. • The radionuclides were measured via low-energy Accelerator Mass Spectrometry. • Neutron fluences in the coral CaCO3 target were estimated at the test site. • A global signal of anthropogenic 10Be in natural archives cannot be expected

  3. 41Ca, 14C and 10Be concentrations in coral sand from the Bikini atoll.

    Lachner, Johannes; Christl, Marcus; Alfimov, Vasily; Hajdas, Irka; Kubik, Peter W; Schulze-König, Tim; Wacker, Lukas; Synal, Hans-Arno

    2014-03-01

    Activation measurements of materials exposed to nuclear bomb explosions are widely used to reconstruct the neutron flux for retrospective dosimetry. In this study the applicability of coral CaCO3 as a biogenic neutron fluence dosimeter is tested. The long-lived radioisotopes (41)Ca, (14)C and (10)Be, which had been produced in nuclear bomb explosions, are measured in several coral sand samples from the Bikini atoll at the 600 kV and 200 kV AMS facilities of ETH Zurich. Elevated concentrations of all studied isotopes are found in a sample from the crater that was initially formed by the high-yield nuclear explosion Castle Bravo in 1954 and that had been used as site for several tests afterward. The observed (14)C concentration is considered too large to originate from neutron irradiation of CaCO3 alone. The relatively low concentration of (10)Be found in the crater sample indicates that production of (10)Be during nuclear bomb testing is generally minor. A simple neutron fluence reconstruction is performed on basis of the (41)Ca/(40)Ca ratio. PMID:24378732

  4. Climate-induced fluctuations of 10Be concentration in Lake Baikal sediments

    Sedimentary 10Be records covering the last 150 kyr were obtained from three cores collected at the Academician Ridge (BDP-96/hole2 core and VER96/st.3 core) and at the Buguldeika Saddle (BDP-93/hole2 core) in Lake Baikal. The 10Be concentrations of the three cores varied between 0.5x109 and 1.5x109 atoms/g, and coincidently dropped at the stratigraphic intervals of marine oxygen isotope stages (MIS) 2, 4, 5d and 6. The depositional fluxes of 10Be, on the other hand, generally rose in those stages having an increase in the dry bulk densities and sediment accumulation rates. These results are consistent with previous work (Horiuchi et al., 1999), suggesting that the dilution effects of low-10Be-concentration particles principally controlled the fluctuations of the 10Be concentrations of Lake Baikal sediments. Low-10Be-concentration particles have been intensively produced by mechanical weathering and physical erosion under the cold and dry climatic conditions during the peak glaciation period, and have been directly brought from the source areas into the lake as a result of the thin vegetative cover of the watershed

  5. Chemical processing for 10Be and 26Al AMS measurements at IUAC

    10Be and 26AI measurements have been carried out at IUAC using its AMS facility based on 15UD Pelletron accelerator since couple of years. A new AMS facility (called XCAMS) based on 500 kV Pelletron accelerator was recently, installed for 14C measurements. Chemical processing is the first and integral part of AMS measurements. Prior to the AMS measurement natural samples undergo series of chemical processes for pre-concentrating element of interest. These chemical procedures are carried out in an ultraclean environment to reduce blank level. Extraction of meteoric 10Be from the sediment samples are being done regularly and have been reported earlier. However, extraction of in situ produced 10Be and 26AI from quartz bearing rocks was started recently

  6. Interlaboratory comparison of 10Be concentrations in two ice cores from Central West Antarctica

    To improve sample processing efficiency for cosmogenic radionuclide measurements in samples from the West Antarctic Ice Sheet Divide core, two chemical lines, one at Purdue University and one at University of California, Berkeley, are being used. Sections from two shallow ice cores from West Antarctica were processed at each lab, while all 10Be accelerator mass spectrometry measurements were performed at PRIME Lab, Purdue University. Duplicate samples gave 10Be results that are identical to within the AMS measurement uncertainties of 2–3%.

  7. 10Be and 7Be concentrations in New Zealand rain (september 1995 to august 1997)

    Monthly rain collections at Lower Hutt, New Zealand (41deg 15 min S; 174 deg 55 min E) between September 1995 and August 1997 have been analysed for 10Be and 7Be, principally to determine flux rates for on-going Be isotope studies of soil, loess, marine sediments and ground water. 10Be concentrations show considerable variation, ranging from 0.5 to 5.0 x 104 atoms cm-3 rain, or 1.2 to 4.2 x 105 atoms cm-2. However, average annual fluxes are relatively constant: 2.7 x 104 atoms cm-3 rain or 31.0 x 105 atoms cm-2 (1995-96); 2.5 x 104 atoms cm-3 rain or 28.1 x 105 atoms cm-2 (1996-97). These results are similar to those derived from 1987 rain sampled at the same location, 2.5 x 104 atoms cm-3 or 28.6 x 105 atoms cm-2, and are similar to published results from other mid-latitude, continental sites in India and USA. 7Be concentrations are also highly variable, ranging from 0.7 to 3.0 x 104 atoms cm-3 or 0.3 to 2.9 x 105 atoms cm-2 (Dec 95 to Aug 97). 7Be/10Be is more constant through the same period, ranging from 0.42 to 0.69, with a mean value of 0.59±0.06 (1σ). Analysis of New Zealand rain collected at Dunedin (45deg 52 min S; 170deg 65 min E) and Auckland (Leigh; 36deg 20 min S; 174deg 50 min E) also began in 1997. Early results for Dunedin indicate similar 7Be/10Be, but generally lower and more variable results for both 7Be and 10Be, compared with Lower Hutt

  8. Meteoric 10Be in Lake Cores as a Measure of Climatic and Erosional Change

    Jensen, R. E.; Dixon, J. L.

    2015-12-01

    Utilization of meteoric 10Be as a paleoenvironmental proxy has the potential to offer new insights into paleoprecipitation records and paleoclimate models, as well as to long-term variations in erosion with climate. The delivery of meteoric 10Be to the surface varies with precipitation and its strong adsorption to sediment has already proven useful in studies of erosion. Thus, it is likely meteoric 10Be concentrations in lake sediments vary under both changing climate and changing sediment influx. Assessment of the relative importance of these changes requires the comparison of 10Be concentrations in well-dated lake cores with independent paleoenvironmental proxies, including oxygen isotope, pollen, and charcoal records, as well as variation in geochemical composition of the sediments. Blacktail Pond details 15,000 years of climatic change in the Yellowstone region. We develop a new model framework for predicting meteoric 10Be concentrations with depth in the core, based on sedimentation rates of both lake-derived and terrigenous sediments and changes in the flux of meteoric 10Be with precipitation. Titanium concentrations and previously determined 10Be concentrations in wind-derived loess provide proxies for changing delivery of 10Be to the lake by terrigenous sources. We use existing paleoenvironmental data obtained from this core and the surrounding region to develop models for changing rainfall across the region and predict meteoric 10Be delivery to the lake by precipitation. Based on a suite of ~10 models, sedimentation rate is the primary control of meteoric 10Be in the Blacktail Pond core unless terrestrial input is very high, as it was post-glacial in the early Holocene when the lake experienced a high influx of loess and terrigenous sediments. We used these models to inform sample selection for 10Be analysis along the Blacktail pond core. Core sediments are processed for meteoric 10Be analysis using sequential digestions and standard extraction procedures

  9. Determination of long-lived radionuclide (10Be, 41Ca, 129I) concentrations in nuclear waste by accelerator mass spectrometry

    Radiological characterization of nuclear waste is essential for storage sites management. However, most of Long-Lived Radionuclides (LLRN), important for long-term management, are difficult to measure since concentration levels are very low and waste matrices generally complex. In an industrial approach, LLRN concentrations are not directly measured in waste samples but assessed from scaling factors with respect to easily measured gamma emitters. Ideally, the key nuclide chosen (60Co, 137Cs) should be produced by a similar mechanism (fission or activation) as the LLRN of interest and should have similar physicochemical properties. However, the uncertainty on the scaling factors, determined from experimental and/or calculation data, can be quite important. Consequently, studies are performed to develop analytical procedures which would lead to determine precisely the concentration of LLRN in nuclear waste. In this context, the aim of this study was to determine the concentrations of three LLRN: 129I (T1/2 = 15.7*106 a), 41Ca (T1/2 = 9.94*104 a) and 10Be (T1/2 = 1.387*106 a) in spent resins used for primary fluid purification in Pressurized Water Reactors using Accelerator Mass Spectrometry (AMS) for measurement. The AMS technique combined mass spectrometry and nuclear physics to achieve highly efficient molecular and elemental isobars separation. Energies of several Million Electron-Volt transferred to the ions in the first accelerating part of specifically developed tandem accelerators lead to molecular isobars destruction through interaction with the argon gas used to strip the injected negative ions to positive ones. At the exit of the tandem accelerator, the energy acquired in both accelerating parts allows an elemental isobars separation based on their significantly different energy loss (dE) while passing through a thickness of matter dx that is proportional to their atomic number (Z) and inversely proportional to ions velocity (v) according to the Bethe

  10. Measurement of 26Al for atmospheric and climate research and the potential of 26Al/10Be ratios

    The measurement of the paired cosmogenic radionuclides 26Al and 10Be in environmental samples has potential applications in atmospheric and climate research. For this study, we report the first measurements of the 26Al/10Be atomic ratio in tropospheric aerosol samples from sites in Europe and Antarctica performed at the Vienna Environmental Research Accelerator (VERA). These initial results show that the 26Al/10Be atomic ratio in tropospheric aerosols averages 1.78 x 10-3 and does not vary significantly between the different locations. We also report results of systematic investigations of the ionization and detection efficiency which we performed to improve the measurement precision for 26Al by AMS. Maximum detection efficiencies of up to 9 x 10-4 (in units of 26Al atoms detected/initial) were achieved for chemically pure Al2O3, while for atmospheric samples we reached efficiencies of up to 2.2 x 10-4

  11. On the measurement of 10Be on the 1 MV compact AMS system at the Centro Nacional de Aceleradores (Spain)

    In this work we present the most recent improvements performed by our group on 10Be measurements on the 1 MV AMS system recently set up at the CNA (Centro Nacional de Aceleradores), in Seville (Spain). Our efforts have been focused on the study of the viability of our system for BeO and BeF- measurements. To achieve this, different standard materials have been measured to demonstrate the reliability of the system for BeO measurements in a wide 10Be/9Be atomic ratio range and several environmental samples have been studied both at the 1 MV AMS CNA facility and at the 6 MV AMS ETH-PSI facility of Zurich to validate our measurements. The results show a good agreement between laboratories. New experiments also have been carried out selecting 1+ and 2+ charge states at the exit of the accelerator and inserting Si3N3.1 foils with different thicknesses to separate 10Be from its isobar, 10B. The influence of each foil on the overall transmission (detected 10Be compared to BeO- injected into the accelerator) and background level was also assessed. In addition some tests were also done to assess the viability of BeF2 and BaBeF4 measurements at our system. Several metal matrices and cathode preparation procedures for BeO samples were investigated to maximize current and cathode lifetime.

  12. Concentration of 10Be in an ice core from the Dome Fuji station, Eastern Antarctica: Preliminary results from 1500 to 1810 yr AD

    We present preliminary data of our 10Be analysis of an ice core retrieved from Dome Fuji station, Eastern Antarctica for 1500-1810 yr AD. The concentration of 10Be from 1500-1810 yr AD ranged between 7.0 x 104 and 13.0 x 104 atoms g-1 and a prominent peak was observed in the period 1645-1715 yr AD (i.e., the Maunder Minimum period). An increase in the concentration was also observed in the periods before 1540 yr AD and near to 1800 yr AD. A comparison of our 10Be record with the South Pole 10Be record shows a clear similarity in their temporal fluctuations. On the other hand, our record shows ∼2.5 times higher concentration of 10Be than in the South Pole record attributable to the difference in local snow accumulation rates. These observations suggest a direct (uncomplicated) fallout of atmospheric 10Be onto inland Antarctica, which in turn, leads to a detailed 10Be stratigraphy throughout this region. We believe that the 10Be profiles of the ice cores from the Dome Fuji station are therefore likely to be a good proxy indicator of changes in solar activity

  13. Relief evolution of the Continental Rift of Southeast Brazil revealed by in situ-produced 10Be concentrations in river-borne sediments

    Salgado, André Augusto Rodrigues; Rezende, Eric de Andrade; Bourlès, Didier; Braucher, Régis; da Silva, Juliana Rodrigues; Garcia, Ricardo Alexandrino

    2016-04-01

    This study aims to quantify the denudation dynamics of the Brazilian passive margin along a segment of the Continental Rift of Southeast Brazil. The denudation rates of 30 basins that drain both horsts of the continental rift, including the mountain ranges of the Serra do Mar (seaside horst); and the Serra da Mantiqueira (continental horst); were derived from 10Be concentrations measured in sand-sized river sediment. The mean denudation rate ranges from 9.2 m Ma-1 on the plateau of the Serra do Mar to 37.1 m Ma-1 along the oceanic escarpment of the Serra do Mar. The seaward-facing scarps of both mountain ranges exhibit mean denudation rates that are approximately 1.5 times those of the inland-facing scarps. The escarpments of the horst nearer to the ocean (Serra do Mar) exhibit higher denudation rates (mean 30.2 m Ma-1) than the escarpments of the continental horst (Serra da Mantiqueira) (mean 16.5 m Ma-1). The parameters that impact these denudation rates include the catchment relief, the slope gradient, the rock and the climate. The incongruent combination of a mountainous landscape and moderate to low 10Be-based denudation rates averaging at ∼20 m Ma-1 suggests a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier.

  14. Patterns of landscape evolution on the central and northern Tibetan Plateau investigated using in-situ produced 10Be concentrations from river sediments

    Li, Yingkui; Li, Dewen; Liu, Gengnian; Harbor, Jon; Caffee, Marc; Stroeven, Arjen P.

    2014-07-01

    Quantifying long-term erosion rates across the Tibetan Plateau and its bordering mountains is of critical importance to an understanding of the interaction between climate, tectonic movement, and landscape evolution. We present a new dataset of basin-wide erosion rates from the central and northern Tibetan Plateau derived using in-situ produced 10Be concentrations of river sediments. Basin-wide erosion rates from the central plateau range from 10.1±0.9 to 36.8±3.2 mm/kyr, slightly higher than published local erosion rates measured from bedrock surfaces. These values indicate that long-term downwearing of plateau surfaces proceeds at low rates and that the landscape is demonstrably stable in the central plateau. In contrast, basin-wide erosion rates from the Kunlun Shan on the northern Tibetan Plateau range from 19.9±1.7 to 163.2±15.9 mm/kyr. Although the erosion rates of many of these basins are much higher than the rates from the central plateau, they are lower than published basin-wide erosion rates from other mountains fringing the Tibetan Plateau, probably because the basins in the Kunlun Shan include both areas of low-relief plateau surface and high-relief mountain catchments and may also result from retarded fluvial sediment transport in an arid climate. Significantly higher basin-wide erosion rates derived from the Tibetan Plateau margin, compared to the central plateau, reflect a relatively stable plateau surface that is being dissected at its margins by active fluvial erosion.

  15. Dating soil layers by 10Be

    The main problem in dating soil layers by the cosmogenic nuclide 10Be is the isolation of beryllium from big quantities of sample materials. The authors apply the following chemical process: leaching the sample material with HCl, extraction of Be as acetylacetonate, and ion exchange on diallyl phosphate. It is thus possible to isolate Be(OH)2 in a chemically pure form containing no other radionuclides. This procedure was tested by the determination of 7Be accumulated in soil. The measured 7Be activity corresponds well with the mean activity of 7Be in rain water. Besides humic acids in soils metal hydroxides are able to concentrate Be to a large extent. Thus 10Be was found in iron ore deposits containing limonite. A calculation of the 10Be production rate is given and the possibility of radioactive dating with 10Be using the chemical process mentioned above is discussed. (author)

  16. FK concentrator outdoor measurements

    Hernández Sanz, Maikel; Vilaplana, J.; Benitez Gimenez, Pablo; Mohedano,, Rubén; Zamora Herranz, Pablo; Miñano Dominguez, Juan Carlos; Mendes Lopes, Joao

    2013-01-01

    The FK is a two-stage optical concentrator for CPV, composed by a Fresnel lens working as POE and a refractive element working as SOE. Both elements perform Köhler integration, for uniform irradiance purposes. The FK has demonstrated that compares very well with other Fresnel-based concentrator optics. Recent on-sun measurements carried out on an FK mono-module prototype have already shown outstanding results, achieving electrical efficiencies over 34%. Further optimization of optical design ...

  17. 10Be chronometry of bedrock-to-soil conversion rates

    Monaghan, Marc C.; McKean, James; Dietrich, William; Klein, Jeffrey

    1992-07-01

    We report concentrations of cosmogenic 10Be ( t1/2 = 1.5 × 10 6 yrs) in soil excavated from a soil-mantled hillslope in Black Diamond Mines Regional Park, Contra Costa County, California. The most striking features of the data are: (1) the similarity in the downward decreasing trends of 10Be concentrations in two soil profiles collected 75 m apart, (2) the coincidence in each soil profile of the soil/bedrock interface (as defined by visual inspection of soil pits) and the level at which 10Be concentrations attain very low values ( ˜4 × 10 6 atoms/g), and (3) the extremely low 10Be concentrations in the underlying regolith (0.5 × 10 6 atoms/gram). The inventory of 10Be in these soils is low, equivalent to about 6000 yrs of 10Be accumulation in a soil initially containing no 10Be. On the basis of these measurements, and with the aid of simple models of soil ( 10Be) motions on the hillslope, we conclude that 10Be loss from the surface is dominated by its removal in soil by creep. We calculate local rates of bedrock-to-soil conversion of between 0.15 and 0.27 km/10 6 yrs. Comparing these with uplift rates determined for coastal regions of California indicates that soil creep alone is capable of removing soil from the local geomorphic system at a rate equivalent to the rate of uplift of much of the coast.

  18. 10Be production calculations in the atmosphere

    Cosmic rays (CRs) interacting with the Earth's atmosphere produce a cascade of secondary particles and cosmogenic nuclides. Cosmogenic nuclides itself are stored in natural archives such as ice cores and can therefore be measured by e.g. accelerator mass spectrometry (AMS). Here we present our calculations of the cosmogenic radionuclide 10Be, which is produced by spallation reactions between secondary neutrons and protons and the atmospheric gases nitrogen and oxygen, using PLANETOCOSMICS, a GEANT4 based computer code (Desorgher[2006]).

  19. Radon Concentrations measurements in ENPD

    Various national and international surveys have demonstrated an increase in radon (222Rn) levels in environment and consequently there is a continuous growing concern about its health effects on the population. Inhalation of indoor radon has long been recognized as a risk to health. The major sources of the indoor radon and its daughters are building materials, natural gas and an underground-derived water supply. In the present work, a set of radon measurements was carried out, using CR-39 solid state nuclear track detector, in different sites in Experimental Nuclear Physics Department (ENPD), Nuclear Research Center (NRC), Atomic Energy Authority (AEA), Egypt. The results showed that the radon concentration and exhalation rate in these sites varied from 10.81 to 264.80 Bq.m-3 and 1.45 to 33.95 mBq.m-2. h-1, respectively. The mean values of radon concentration in meeting rooms, laboratories, stores and bathroom) were 31.211, 198.22, 221.64 and 168.34 Bq.m-3, respectively. The mean values of exhalation rate were (in the same locations) 4, 25, 28.42 and 21.58 mBq.m-2.h-1 respectively. This data showed that stores and laboratories had a significantly higher radon concentration and exhalation rate compared with other rooms.

  20. Terrigenous supply of 10Be and dating with 14C and 10Be in sediments of the Angola basin (SE Atlantic)

    10Be concentrations were measured in 20 (hemi)pelagic core top samples with an age control partly based on AMS 14C datings. The 10Be concentrations do not show any dependence on the bulk mass accumulation rates (MAR), but there is a significant linear correlation between 10Be accumulation rates and MAR. This correlation is best explained by terrigenous 10Be supply modified by biologic scavening and, of secondary importance, adsorption on particulate matter in the ocean surface water in the Zaire plume. The variable term of the linear regression function indicates a maximum 10Be concentration for the terrigenous component of 5x109 at.g-1, the constant suggests an oceanic 10Be precipitation of (100-530)x106 at.cm-2 ka-1. A 500 ka long record of 10Be concentrations is in agreement with the predicted values, but short-term variations in MAR obscure the expression of a long-term break in MAR about 350 ka ago. (orig.)

  1. The Novel Cluster States in 10Be

    We have investigated the cluster structures in 10Be by using 6He+α cluster wave functions and dineutron condensate wave functions. We suggested two kinds of exotic cluster states which have not been confirmed experimentally yet. One of them has a gas-like structure of two alphas and one dineutron, and another has 6He and an extremely developed α. (author)

  2. Two novel cluster states in 10Be

    We have investigated the cluster structure of 10Be by using 6He+α cluster wave functions and 2α+2n dineutron condensate wave functions. We found two novel cluster 0+ states, one of which has an α+α+dineutron gas-like structure and the other contains 6He and a well-separated α cluster. In this paper, we discuss their cluster structures.

  3. Novel cluster states in $^{10}$Be

    Kobayashi, Fumiharu; Kanada-En'yo, Yoshiko

    2012-01-01

    Cluster structures of excited $^{10}$Be states are investigated with a hybrid model of dineutron condensate wave functions and $^6$He+$\\alpha$ cluster wave functions. Two kinds of cluster states are theoretically suggested a few MeV above the $\\alpha+\\alpha+n+n$ threshold energy. They have quite distinct cluster structure; ones have gas-like structures of $\\alpha+\\alpha$+dineutron, and the others have $^6$He+$\\alpha$ with extremely extended an $\\alpha$ cluster. Although these cluster states h...

  4. Authigenic 10Be/9Be ratios and 10Be-fluxes (230Thxs-normalized) in central Baffin Bay sediments during the last glacial cycle: Paleoenvironmental implications

    Simon, Quentin; Thouveny, Nicolas; Bourlès, Didier L.; Nuttin, Laurence; Hillaire-Marcel, Claude; St-Onge, Guillaume

    2016-05-01

    Authigenic 10Be/9Be ratios and 10Be-fluxes reconstructed using the 230Thxs normalization, proxies of the cosmogenic radionuclide 10Be production rate in the atmosphere, have been measured in a sedimentary core from Baffin Bay (North Atlantic) spanning the last 136 ka BP. The normalization applied on the exchangeable (authigenic) 10Be concentrations using the authigenic 9Be isotope and 230Thxs methods yield equivalent results strongly correlated with sedimentological parameters (grain-size and mineralogy). Lower authigenic beryllium (Be) concentrations and 10Be/9Be ratios are associated with coarse-grained carbonate-rich layers, while higher authigenic Be values are related to fine-grained felspar-rich sediments. This variability is due to: i) sediment composition control over beryllium-scavenging efficiency and, ii) glacial history that contributed to modify the 10Be concentration in Baffin Bay by input and boundary scavenging condition changes. Most paleo-denudation rates inferred from the 10Be/9Be ratio vary weakly around 220 ± 76 tons.km-2.yr-1 (0.09 ± 0.03 mm.yr-1) corresponding to relatively steady weathering fluxes over the last glacial cycle except for six brief intervals characterized by sharp increases of the denudation rate. These intervals are related to ice-surging episodes coeval with Heinrich events and the last deglaciation period. An average freshwater flux of 180.6 km3.yr-1 (0.006 Sv), consistent with recent models, has been calculated in order to sustain glacially-derived 10Be inputs into Baffin Bay. It is concluded that in such environments, the authigenic 10Be measured mainly depends on climatic effects related to the glacial dynamics, which masks the 10Be production variation modulated by geomagnetic field changes. Altogether, these results challenge the simple interpretation of 10Be-concentration variation as a proxy of Interglacial/Glacial (interstadial/stadial) cycles in Arctic and sub-Arctic regions. They rather suggest the effect

  5. Surface exposure dating using in situ cosmogenic 10Be

    Surface exposure dating using in situ cosmogenic 10Be in quartz is an important new tool in Quaternary research. We give an introduction into the method and describe, how 10Be surface exposure ages are measured and calculated at the Institute of Soil Science and Soil Geography at the University of Bayreuth, Germany. (author)

  6. Excited state halos in 10Be

    The structure of certain bound excited states in 10Be have been shown to have exotic features because of their weak binding and cluster-like configurations. In this article, we investigate E1 and E2 transitions between these states and compare the findings with recent experimental results. We compare the predictions of two types of structure calculations: a microscopic multicluster model and an ab initio no-core shell model. Both predict very similar transition strengths. By considering the relative contributions from the various matrix elements contributing to the transitions arising from the coupling of different 9Bexn configurations in the wave functions making up the states, we conclude that the very weak B(E1;2-→21+) can only be understood if the 2- state (with a separation energy of its predominantly 1s1/2 neutron of just 0.548 MeV) is a clear halo state. Other nearby states, such as the 22+, do not exhibit a clear halo signature because of the less than clean decoupling into the well-defined 9Be core plus halo neutron

  7. {sup 10}Be application to soil development on Marion Island, southern Indian Ocean

    Haussmann, N. [Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602 (South Africa); Aldahan, A., E-mail: ala.aldahan@geo.uu.s [Department of Earth Sciences, Uppsala University (Sweden); Department of Geology, United Arab Emirates University, Al-Ain (United Arab Emirates); Boelhouwers, J. [Department of Earth Sciences, Uppsala University (Sweden); Possnert, G. [Tandem Laboratory, Department of Engineering Science, Uppsala University (Sweden)

    2010-04-15

    Marion Island, located in the southern Indian Ocean, constitutes the summit of an active shield volcano. It is a small terrestrial environment where glacially abraded bedrock became exposed c x 10 kyr ago. These conditions provide an interesting possibility for the assessment of {sup 10}Be accumulation rates and their application to soil erosion studies on the island. {sup 10}Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a {sup 10}Be precipitation flux several times higher than model prediction. Estimation of the {sup 10}Be accumulation based on the soil inventory suggests a span between 2000 and 7000 yr. This time span is not in accordance with the accepted notion that the island was covered with ice about 10,000 yr ago and suggests either removal of {sup 10}Be from the soil profile, an overestimated Holocene {sup 10}Be-flux or a delayed soil development history. Our results provide new data on {sup 10}Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere {sup 10}Be database.

  8. 10Be application to soil development on Marion Island, southern Indian Ocean

    Marion Island, located in the southern Indian Ocean, constitutes the summit of an active shield volcano. It is a small terrestrial environment where glacially abraded bedrock became exposed c x 10 kyr ago. These conditions provide an interesting possibility for the assessment of 10Be accumulation rates and their application to soil erosion studies on the island. 10Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a 10Be precipitation flux several times higher than model prediction. Estimation of the 10Be accumulation based on the soil inventory suggests a span between 2000 and 7000 yr. This time span is not in accordance with the accepted notion that the island was covered with ice about 10,000 yr ago and suggests either removal of 10Be from the soil profile, an overestimated Holocene 10Be-flux or a delayed soil development history. Our results provide new data on 10Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere 10Be database.

  9. 10Be application to soil development on Marion Island, southern Indian Ocean

    Haussmann, N.; Aldahan, A.; Boelhouwers, J.; Possnert, G.

    2010-04-01

    Marion Island, located in the southern Indian Ocean, constitutes the summit of an active shield volcano. It is a small terrestrial environment where glacially abraded bedrock became exposed c × 10 kyr ago. These conditions provide an interesting possibility for the assessment of 10Be accumulation rates and their application to soil erosion studies on the island. 10Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a 10Be precipitation flux several times higher than model prediction. Estimation of the 10Be accumulation based on the soil inventory suggests a span between 2000 and 7000 yr. This time span is not in accordance with the accepted notion that the island was covered with ice about 10,000 yr ago and suggests either removal of 10Be from the soil profile, an overestimated Holocene 10Be-flux or a delayed soil development history. Our results provide new data on 10Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere 10Be database.

  10. Do Fungi Transport 10Be During Wood Degradation?

    Conyers, G.; Granger, D. E.

    2010-12-01

    Meteoric cosmogenic 10Be is increasingly used to determine erosion and soil transport rates. To calculate these rates, it is assumed that 10Be is a conservative passive tracer of soil particles. However, there is experimental evidence that beryllium is mobilized in natural soils complexed with organic acids. For example, up to 50% of beryllium can be mobilized by humic acids in soils at pH 7 (Takahashi et al., 1999). Beryllium is also known to be taken up in plants such as tobacco and vegetables (World Health Organization, 1990) at ppm levels, primarily as organic acid chelates. It is not known to what extent biological beryllium transport in the environment affects the cosmogenic 10Be budget, or how it influences beryllium mobility. In this study, we address a problem recognized early in the development of meteoric 10Be methods. It has been observed that decayed organic matter in soils and sediments contains very high concentrations of 10Be of up to 109-1010 atoms/g (Lundberg, et al., 1983). On the other hand, living trees contain much lower concentrations of 106 atoms/g (Klein et al., 1982). The driving question for this study is how 10Be becomes bound to decayed organic matter. Direct fallout seems unlikely as the residence time of organic matter in soil is too short. One possibility is that 10Be is transported by fungi. Wood-degrading fungi are known to transport and bioaccumulate metals from large areas, facilitated by acids such as oxalic acid in the fungal hyphae. To test the hypothesis that fungi transport 10Be, we analyzed both intact and fungally degraded wood of oak, hickory, and hemlock. From these data, we reached two conclusions (observations?): 1) Oak has a 10Be concentration of about 2x106 at/g, similar to that observed by Klein et al. (1982). Hickory has a significantly higher concentration of about 3x107 atoms/g, confirming observations that hickory bioaccumulates beryllium. Using these data, the inventory of 10Be in a temperate forest is expected

  11. Nonlinear optical measurements of glucose concentration

    Yakovlev, V. V.

    2008-02-01

    Diabetes mellitus is a metabolic disease that currently affects about 7% of the US population, or roughly about 20 million people. Effectively controlling diabetes requires regular measurements of the blood sugar levels to ensure the one time insulin injection when the concentration of glucose reaches a critical level. In this report, nonlinear Raman microspectroscopy is demonstrated to be a promising new way of continuous and noninvasive way of measuring the glucose concentration.

  12. Measuring probe for radon concentration monitoring

    Variation of radon emanation in mining excavation is caused by changes of stress in geologic layer, coal or other minerals are extracted from. To investigate this phenomenon, a model of an instrument for continuous monitoring of radon concentration in mine environment was developed. The measuring head constructed in the form of a cylinder operates with modified mining radiometer RGR-40. The instrument can measure radon concentration employing the method of natural diffusion of radon to the measuring head, or forced air sampling by an membrane air pump. The measuring results are stored in internal memory of the instrument and are displayed on LCD screen. (author)

  13. Measurement of HD concentration by gas chromatography

    Gas chromatography has been used for the on-line measurement of deuterium hydride (HD) which is used in a Tritium Removal Pilot Facility for the demonstration of the removal of the tritium mainly generated in CANDU reactors. Two methods with different carrier gases, neon and hydrogen, are tested and compared each other. It was showed that both the methods could be possible to measure the concentration of H2 and HD. However, the method with a column packed with alumina showed difficulty in the application due to quite long measurement time and reproducibility. The other method using hydrogen as a carrier gas could measure the concentration accurately within comparably short period

  14. Radon concentration measurements in bituminous coal mines

    Radon measurements were carried out in Kozlu, Karadon and Uezuelmez underground coal mines of Zonguldak bituminous coal basin in Turkey. Passive-time integrating method, which is the most widely used technique for the measurement of radon concentration in air, was applied by using nuclear etched track detectors (CR-39) in the study area. The radon concentration measurements were performed on a total of 42 points in those three mines. The annual exposure, the annual effective dose and lifetime fatality risk, which are the important parameters for the health of workers, were estimated based on chronic occupational exposure to the radon gas, which is calculated using UNCEAR-2000 and ICRP-65 models. The radon concentrations at several coal production faces are higher than the action level of 1000 Bq m-3. It is suggested that the ventilation rates should be rearranged to reduce the radon concentration. (authors)

  15. Measurements of natural 41Ca concentrations

    Atomic mass spectroscopic examinations on 41Ca were carried out in the UNILAC accelerator. A sensitivity of about 10-15 was achieved. This would allow the measurement of present natural 41Ca concentrations as soon as the problem of the transmission determination is solved. In this respect suggestions were worked out and their feasibility discussed. The detection of 41Ca-ions is especially free of background when high UNILAC-energies are applied. An estimation showed a background level corresponding with a 41Ca concentration of less then 10-17 referred to 40Ca. Besides an independent concept for the electromagnetic concentration of 41Ca with variable concentration factors was developed. After being concentrated up to 50 respectively 25 times the initial concentration in the GSI mass separator, the 41Ca concentration of three recent deer bones found in the Odenwald was measured by atomic mass spectroscopy in the 14UD-Pelletron Tandem in Rehovot (Israel). The measured 41Ca concentrations ranged between 10-14 to 10-13 with consideration of the concentration factor. A theoretical study of the 41Ca production in the earth's surface based on cosmic radiation illustrates the influence of trace elements on the neutron flux and thus on the 41Ca production. This influence might be a possible explanation for the observed amplitude of variation of the 41Ca concentration in recent bones which are of decisive importance for the feasibility of 41Ca-related dating. In this work a method is suggested that does not depend on the amplitude of variation mentioned above and which would allow the determination of the erosion rate of rocks by its 41Ca concentrations. (orig./HP)

  16. Cosmogenic 10Be, 21Ne and 36Cl in sanidine and quartz from Chilean ignimbrites

    Our initial results indicate that three cosmogenic nuclides: 10Be, 21Ne and 36Cl can be analyzed in sanidine. To uncover complex exposure histories or marked changes in denudation rates over time several nuclides with different half-lives (or stable) must be measured. Because of its shorter half-life, the combination of 36Cl and a long-lived nuclide 10Be or stable nuclide 21Ne will provide more information than the pairs 10Be and 26Al or 10Be and 21Ne (in quartz). Sanidine (alkali feldspar) is a common high temperature mineral and often dominates the phenocryst assemblage in silicic to intermediate volcanic rocks. Bedrock surfaces studied come from the Oxaya (erupted 19-23 Ma) and Lauca (erupted 2.7 Ma) ignimbrites of northern Chile. Quartz and sanidine phenocrysts coexist; therefore, we can check the viability of sanidine through direct comparison with nuclide concentrations in quartz. In addition, as quartz has no target for 36Cl in significant abundance we show that the unique power of sanidine is that 36Cl can be measured. We have obtained very good agreement between 10Be and 21Ne concentrations measured in sanidine and coexisting quartz. No meteoric 10Be was apparent in these sanidines. Concentrations of all three nuclides in mineral separates from rock sample CN309 from the Lauca ignimbrite in the Western Cordillera agree well and correspond to minimum exposure ages of 30-50 ka. 10Be and 21Ne measured in both sanidine and quartz from three rock samples from the Oxaya ignimbrite (CN19, CN23, CN104a) in the Western Escarpment record low average landscape modification rates (36Cl data from sanidine in CN23 seem to indicate shorter minimum exposures and more rapid maximum erosion rates

  17. Applications of 10Be, 14C, and 32Si to geological questions

    Radiometric dating is regarded as fundamental to any modern timescale calibration. In terms of available isotopic dating and tracing tools in environmental sciences, the cosmogenic isotopes stand out because of their application in the range from the very recent up to the middle Miocene. At IGNS, three long-lived cosmogenic isotopes can be measured. 14C (half life=5730 years) and 10Be (half-life = 1.5 Ma) are measured by Accelerator Mass Spectrometry (AMS) of 10Be/9Be and 14C/13C ratios, while 32Si (half-life > 140 years) is measured by radioactive decay counting of its daughter-product 32P. The main advantage of AMS over decay counting is the relatively small amount of sample material needed. AMS has made it feasible to measure ultra-low concentrations of long-lived isotopes such as 10Be. (author)

  18. In-line acid concentration measuring method and measuring probe

    Kuno, Takehiko; Kurosawa, Akira; Sato, Soichi

    1998-09-11

    A measuring probe comprising an electrode for voltammetry, a supersonic sensor and a conductivity measuring electrode formed integrally is immersed in a solution for a reprocessing step. A relationship between an acid concentration of the solution having U and Pu concentrations as variable parameters and a propagation speed of supersonic waves in the solution is previously determined, and a propagation speed of the supersonic waves in the solution for the reprocessing step is measured. An acid concentration is determined by using U and Pu concentrations of the solution of the reprocessing step measured in-line by using voltammetry based on the relationship between the acid concentration at that U and Pu concentrations and the supersonic propagation speed. In addition, conductivity of the liquid for the step is measured by a solution conductivity meter, and an acid concentration is measured in-line based on the relationship between the acid concentration and the conductivity in the same manner. With such procedures, a reprocessing plant can be operated rapidly and smoothly, as well as the analysis operation can be simplified. (T.M.)

  19. In-line acid concentration measuring method and measuring probe

    A measuring probe comprising an electrode for voltammetry, a supersonic sensor and a conductivity measuring electrode formed integrally is immersed in a solution for a reprocessing step. A relationship between an acid concentration of the solution having U and Pu concentrations as variable parameters and a propagation speed of supersonic waves in the solution is previously determined, and a propagation speed of the supersonic waves in the solution for the reprocessing step is measured. An acid concentration is determined by using U and Pu concentrations of the solution of the reprocessing step measured in-line by using voltammetry based on the relationship between the acid concentration at that U and Pu concentrations and the supersonic propagation speed. In addition, conductivity of the liquid for the step is measured by a solution conductivity meter, and an acid concentration is measured in-line based on the relationship between the acid concentration and the conductivity in the same manner. With such procedures, a reprocessing plant can be operated rapidly and smoothly, as well as the analysis operation can be simplified. (T.M.)

  20. Measurement of Odour Concentration from Livestock Farm

    Lukman Ismail; Zaini Sakawi; Mohamad Khalil Saipi

    2014-01-01

    Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter ...

  1. Measuring protein concentration with entangled photons

    Crespi, Andrea; Matthews, Jonathan C F; Politi, Alberto; Neal, Chris R; Ramponi, Roberta; Osellame, Roberto; O'Brien, Jeremy L

    2011-01-01

    Optical interferometry is amongst the most sensitive techniques for precision measurement. By increasing the light intensity a more precise measurement can usually be made. However, in some applications the sample is light sensitive. By using entangled states of light the same precision can be achieved with less exposure of the sample. This concept has been demonstrated in measurements of fixed, known optical components. Here we use two-photon entangled states to measure the concentration of the blood protein bovine serum albumin (BSA) in an aqueous buffer solution. We use an opto-fluidic device that couples a waveguide interferometer with a microfluidic channel. These results point the way to practical applications of quantum metrology to light sensitive samples.

  2. Measurement of Odour Concentration from Livestock Farm

    Lukman Ismail

    2014-08-01

    Full Text Available Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter Xp-369 Series III. Measurement was taken during various weather and times, usually on normal days and after rains. Observationswere conducted at different times inthe mornings, evenings and nights. Ten stations were selected as locations for measuring the odour concentration within two kilometres from the livestock farms. The results indicated that after rain odour concentration gave higher readings compared to those of normal days.This phenomenon was caused by the meteorological factors such as temperature, comparative humidity; and variation in wind speed and directions on normal days and after rains.Enhancement of livestock management is suggested for mitigating the odour pollution.

  3. Attenuation of cosmogenic 10Be production in the first 20 cm below a rock surface

    Cosmogenic 10Be has been measured in short drill cores taken from a glacially polished cliff surface. The high-resolution concentration depth profile is compared to theoretical profiles of various attenuation lengths and different shapes near the surface. Preliminary modeling results shows that long apparent attenuation lengths and perhaps a non-decreasing or 'flat' section right below the surface are best suited to bring experiment and theory into agreement

  4. Measuring concentrations of elements using neutron radiation

    An apparatus for measuring the concentrations of elements in a material by the capture gamma method is claimed. The apparatus comprises either an isotope source or a neutron generator as the neutron source, a semi-conductor detector as the gamma-radiation detector, and a moderator which is, at least in part, heavy water. The detector is adapted to be placed adjacent to or inside a specimen in the flux of slow neutrons so that sufficient moderator is disposed between the source and the sample-detector combination that only relatively few fast neutrons will reach the detector

  5. Linking ice sheet and lake sediment archives of 10Be, 1468–1980 CE

    As part of understanding and reconstructing our climate history it is important to investigate the link between climate and solar activity. Ice cores and ocean sediments have provided information on a range of timescales on atmospheric 10Be production, which is a proxy for past solar activity due to its cosmogenic nature of production. We here present results from the first, to our knowledge, multi-centennial and annual resolution study of 10Be in varved lake sediments. Varves were sampled over an interval covering the period 1468–2006 CE in sediment cored from Lake Lehmilampi in eastern Finland. The measured concentrations were converted into annual 10Be deposition rates by using the weights of dried samples as an estimation of sedimentation rates and scaling the result from sampling to catchment area size. We compare the lake catchment 10Be deposition rates to those derived from the Greenlandic ice cores NGRIP and Dye-3 along with past solar activity. Sediment 10Be concentrations range 2.1–17.6 × 108 atoms g−1. The high end of this range is represented by a limited number of samples, and the average is near the lower end at 4.1 × 108 atoms g−1. The deposition rates range 0.5–3.9 × 106 atoms cm−2 year−1, with an average of 1.8 × 106 atoms cm−2 year−1 (0.057 atoms cm−2 s−1). We note higher 10Be deposition during the Spörer (∼1415–1535 CE) and Maunder (∼1645–1715 CE) solar minima, and also at the onset of the Dalton (∼1790–1830 CE) minimum. Equally high 10Be values in the 1840s and lower deposition during the Dalton minimum are not consistent with contemporaneous solar activity. Although this may in part be a result of incomplete measurements in the 19th century, it also shows the complexity of deposition and the intricacy of reconstructing past solar activity from sediment 10Be data. A comparison with ice core data reveals particularly good agreement between sediment and Dye-3 10Be flux around 1500–1750 CE.

  6. Linking ice sheet and lake sediment archives of {sup 10}Be, 1468-1980 CE

    Berggren, Ann-Marie, E-mail: berggrenannmarie@gmail.com [Dept. of Earth Sciences, Uppsala University, Villav 16, SE-752 36 Uppsala (Sweden); Aldahan, Ala [Dept. of Earth Sciences, Uppsala University, Villav 16, SE-752 36 Uppsala (Sweden); Dept. of Geology, United Arab Emirates University, P.O. Box 17551, Al Ain (United Arab Emirates); Possnert, Goeran [Tandem Laboratory, Uppsala University, P.O. Box 529, SE-751 20 Uppsala (Sweden); Haltia-Hovi, Eeva [Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, D-14473 Potsdam (Germany); Dept. of Geology, University of Turku, FI-20014-Turku (Finland); Saarinen, Timo [Dept. of Geology, University of Turku, FI-20014-Turku (Finland)

    2013-01-15

    As part of understanding and reconstructing our climate history it is important to investigate the link between climate and solar activity. Ice cores and ocean sediments have provided information on a range of timescales on atmospheric {sup 10}Be production, which is a proxy for past solar activity due to its cosmogenic nature of production. We here present results from the first, to our knowledge, multi-centennial and annual resolution study of {sup 10}Be in varved lake sediments. Varves were sampled over an interval covering the period 1468-2006 CE in sediment cored from Lake Lehmilampi in eastern Finland. The measured concentrations were converted into annual {sup 10}Be deposition rates by using the weights of dried samples as an estimation of sedimentation rates and scaling the result from sampling to catchment area size. We compare the lake catchment {sup 10}Be deposition rates to those derived from the Greenlandic ice cores NGRIP and Dye-3 along with past solar activity. Sediment {sup 10}Be concentrations range 2.1-17.6 Multiplication-Sign 10{sup 8} atoms g{sup -1}. The high end of this range is represented by a limited number of samples, and the average is near the lower end at 4.1 Multiplication-Sign 10{sup 8} atoms g{sup -1}. The deposition rates range 0.5-3.9 Multiplication-Sign 10{sup 6} atoms cm{sup -2} year{sup -1}, with an average of 1.8 Multiplication-Sign 10{sup 6} atoms cm{sup -2} year{sup -1} (0.057 atoms cm{sup -2} s{sup -1}). We note higher {sup 10}Be deposition during the Spoerer ({approx}1415-1535 CE) and Maunder ({approx}1645-1715 CE) solar minima, and also at the onset of the Dalton ({approx}1790-1830 CE) minimum. Equally high {sup 10}Be values in the 1840s and lower deposition during the Dalton minimum are not consistent with contemporaneous solar activity. Although this may in part be a result of incomplete measurements in the 19th century, it also shows the complexity of deposition and the intricacy of reconstructing past solar activity

  7. Intercomparison of soil radon concentration measurements

    In October last year the first intercomparison of measurements of the soil radon concentrations between various laboratories in Slovakia was realised. The organisation of this intercomparison was conducted by the Slovak Legal Metrology in Banska Bystrica together with the Slovak National Accreditation Service in Bratislava (SNAS). The scientific guarantee of the exercise was the State metrological Centre for radon quantities, which is working at the Research base of Slovak Medical University in Bratislava. The main objective of the intercomparison was to verify the correctness of the methods for the soil radon measurements of the authorised laboratories for radon volume activities in soil air. The intercomparison (signed as SLM ILC 3/03) was performed as a 'circular' metrology comparison, in accordance with a methodical directive MSA 0117-98, published by SNAS. Six laboratories were participating on the intercomparison and there have been two stages of the work one in the radon chamber of the State metrological Centre and the second in the real field conditions. The results of the exercise have confirmed the capability of the participating laboratories for licensing of their measurements as authorised laboratories. The achieved accuracy, as well as the level of technical skill of the participants are a significant step for quality assurance improvement and for optimisation of the soil radon measurements. (authors)

  8. Measurement of radon activity concentration in buildings

    Radon exposure, along with medical-related exposure, is the leading source of exposure to ionising radiation for the French population. Measurement campaigns are done in the action plan, drawn up by the French nuclear safety authority (ASN), in cooperation with the French directorate for housing, town planning and countryside (DHUP), the French radiation protection and nuclear safety institute (IRSN), the French health monitoring institute (InVS) and the French scientific and technical centre for construction (CSTB). The review of 2005-2008 measurement campaign shows that of the 7356 buildings screened, 84.8% had activity concentration levels below the 400 Bq/m3 action level. For the other buildings (15.2%), action will be required to reduce human exposure to radon, possibly including building renovation/redevelopment work. In the 1999-2002 measurement campaign,12% of the 13,000 buildings screened had a radon activity concentration level higher than 400 Bq/m3. In addition, the ASN and the French general directorate of labour (DGT) are continuing to work on drawing up regulations for occupational risk management. The second national health and environment plan (PNSE 2) was published on 26 June 2009. It follows on from the actions initiated in PNSE 1, a document provided for under the Public Health Act dated 9 August 2004 and under the French 'Grenelle' environmental agreements. On the basis of guidelines laid out in PNSE 2, a radon action plan for 2009-2012 will be drawn up, enabling some of the actions to be continued, particularly in the fields of new building projects and dwellings. (author)

  9. Accuracy of 9Be-data and its influence on 10Be cosmogenic nuclide data

    A 9Be-solution has been chemically prepared from phenakite (Be2SiO4) mineral grains as commercial 9Be-solutions are too high in long-lived 10Be. The solution is intended to be used as a carrier for radiochemical separation of 10Be to be measured by accelerator mass spectrometry (AMS). Thus, accurate data of the 9Be-concentration of this solution is essential to guarantee for high-accuracy 10Be data in the future. After devastating preliminary results (∼8 % standard deviation), eight laboratories finally produced twelve individual results by four different analytical methods. A certain lab and method bias might be identified by sophisticated statistical evaluation. Some laboratories also (grossly) underestimate their uncertainties. Thus, the simple weighted mean of this round-robin exercise needed to be corrected by introducing additional allowances (Paule-Mandel-approach). The final result has been calculated to (2,246 ± 11) μg 9Be/(g solution) with a reasonably low weighted standard deviation of 0.49 %. The maximum deviation of a single lab value from the weighted mean is 2.4 % when removing one Grubbs outlier (11 % off from the mean) from the data set. As 10Be-data, which is usually calculated from measured 10Be/9Be by AMS and stable 9Be, cannot be more accurate than the determined 9Be-concentration, it seems highly advisable to establish or improve quality assurance by having self-made carrier-solutions analysed at more than a single lab and regularly taking part in round-robin exercises. (author)

  10. Analytical Methods for Uranium Concentration Measurements

    A survey of analytical procedures for the determination of uranium, as performed for NMM in the United States of America, is presented. Methods are outlined for the measurement of the element in a variety of materials, i.e. ores, concentrates, uranium metal, alloys, ceramics, compounds of uranium, scrap processing solutions, residues, and waste stream products. It is not intended as a complete résumé dealing with the subject, but it does offer measurement methods believed to give precise and accurate results of a high order. Because of the monetary value of the materials, and the transfer activities from one installation to another, involving payments or credits, burn-up charges, use charges, etc., it is essential that such methods are used. Methods of analysis to a large extent are dictated by the types of material to be analysed. The use of gravimetric methods are reviewed pertaining to product materials, which are generally defined as uranium metal, or compounds of the metal, such as oxides, halides, or nitrates. A pyro-hydrolysis technique is included under this heading. Non-volatile metallic impurities are determined spectroscopically, and the gravimetric results are corrected accordingly. Volumetric procedures, the ''workhorse'' methods for determining uranium, are thoroughly explored. The technique is applicable to all types of material, providing the uranium available for measurement is present in milligram quantities. Due to the valence states of uranium, reduction-oxidation schemes are particularly attractive. Dissolution problems, separation of interfering elements, reduction steps, and oxidation titrations of reduced uranium are discussed. The application of certain spectrophotometric and fluorometric procedures for analysing low-grade materials are included. Various separation steps incorporated in the procedures before the determination of uranium are reviewed. Along these lines the utilization of differential colorimetry is examined for determining

  11. 10Be as paleoclimatic tracer. Initial results from south western Indian Ocean sediments

    The variations in the concentration of 10Be in the core (SK 200/23) from south western Indian Ocean apparently illuminate past levels of 10Be. The level in the core where lower concentration of 10Be (1.01 x 109 atoms/g) is encountered during the Late Holocene is not at tandem with the Late Holocene southern hemisphere temperature variation. The results further suggest that during last glacial maxima (LGM) the 10Be concentration is higher (2.67 x 109 atoms/g) than the Late Holocene values. The present results, though preliminary, show that local bottom topography seems to have influenced the 10Be concentration at core site. Many studies from different geographic regions need to be undertaken before we finally consider 10Be as yet another strong proxy for palaeoclimatic reconstructions. (author)

  12. Dating Antarctic soils with atmospherically-produced 10Be

    Traditionally, dating on-land soils (tills) in Antarctica has proved difficult due to a lack of suitable and reliable methods, and an absence of fixed points by which ages can be accurately determined. Cosmogenic isotopes, in particular 10Be, offer a solution to this problem through the application of surface exposure dating. Surface exposure dating of substrate, bouldery flows or tills can provide useful minimum ages, but is limited by uncertainties regarding production rates, degree of erosion and/or pre-existing snow/soil cover, and tectonism. Dating soils using 10Be has its own set of limitations, but a range of new interpretative approaches has recently yielded some promising results. However, it is difficult to accurately estimate 10Be flux, which can differ by orders of magnitude both spatially and over geological time. Alternatively 10Be/9Be ratios of easily leachable soil components, produced near the soil surface by equilibrium of atmospheric 10Be and common Be (9Be), may be presumed to be independent of 10Be flux. In soil of pH less than 5, this Be becomes relatively mobile and moves downwards slowly over several My, yielding 10Be/9Be decay curves from which age information can be inferred. An even more promising approach relies on an observed close correlation between 10Be ages, independent age estimations and nitrate inventories. The nitrate, like 10Be, is derived from chemical reactions in the stratosphere and is known to gradually accumulate with time in Antarctic soils as part of the total salt inventory. Evidence suggests that nitrate flux into the soils may be temporally and spatially constant. This suggests that, if they can be independently age calibrated (using 10Be/9Be), nitrate inventories could provide a reliable and widely applicable estimate of soil ages in Antarctica

  13. Using meteoric 10Be to constrain the age and structure of the frontal wedge at the Japan Trench

    Regalla, C.; Bierman, P. R.; Rood, D.; Motoyama, I.; Fisher, D. M.

    2013-12-01

    We present new meteoric 10Be concentration data from marine sediments recovered during International Ocean Drilling Program (IODP) Exp. 343 that help constrain the age and internal structure of the frontal prism at the Japan trench in the vicinity of the 2011 Tohoku-oki M9 earthquake rupture. Exp. 343 recovered sediments from an ~200 m interval of the frontal wedge at site C0019. Core and log observations identify the plate boundary décollement at ~820 mbsf, which separates a deformed sedimentary wedge from relatively undeformed underthrust sediments. However, reconstructions of the structural evolution of the wedge are difficult because of similarity in lithology between sediments from the incoming and overriding plate, and the chaotic character of seismic reflectors in the frontal wedge. We utilize the radiogenic decay of 10Be (t1/2 =1.36 Ma) in marine sediments to constrain variations in sediment age with depth in core C0019. Meteoric 10Be was isolated from marine sediments at the University of Vermont using total fusion and 10Be/9Be ratios were measured at the Scottish Universities Environmental Research Centre. Concentrations of meteoric 10Be in core C0019 range from 1.7x107 to 2.1x109 atm/g and are consistent with 10Be concentrations at nearby DSDP sites 436 and 434. We calculate 10Be sediment ages for analyzed samples assuming a range of initial 10Be concentrations from 1.6 to 2.1x109 atm/g. These concentrations are constrained by a 10Be sample co-located with a radiolarian micropaleontology sample at 780 mbsf that yields a Quaternary age, and from previously reported 10Be concentrations for Quaternary sediments in nearby DSDP cores. 10Be and radiolarian micropaleontology samples from similar depths yield consistent ages for late Miocene to Quaternary sediments (R2 = 0.89). Calculated 10Be ages range from 0-10 Ma, with ~50% of analyzed samples yielding ages <2 Ma. Repetition and inversion of high (109 atm/g) and low (107 atm/g) concentration sediments with

  14. Studies of Be migration in the JET tokamak using AMS with 10Be marker

    Bykov, I.; Bergsåker, H.; Possnert, G.; Zhou, Y.; Heinola, K.; Pettersson, J.; Conroy, S.; Likonen, J.; Petersson, P.; Widdowson, A.

    2016-03-01

    The JET tokamak is operated with beryllium limiter tiles in the main chamber and tungsten coated carbon fiber composite tiles and solid W tiles in the divertor. One important issue is how wall materials are migrating during plasma operation. To study beryllium redistribution in the main chamber and in the divertor, a 10Be enriched limiter tile was installed prior to plasma operations in 2011-2012. Methods to take surface samples have been developed, an abrasive method for bulk Be tiles in the main chamber, which permits reuse of the tiles, and leaching with hot HCl to remove all Be deposited at W coated surfaces in the divertor. Quantitative analysis of the total amount of Be in cm2 sized samples was made with inductively coupled plasma atomic emission spectroscopy (ICP-AES). The 10Be/9Be ratio in the samples was measured with accelerator mass spectrometry (AMS). The experimental setup and methods are described in detail, including sample preparation, measures to eliminate contributions in AMS from the 10B isobar, possible activation due to plasma generated neutrons and effects of diffusive isotope mixing. For the first time marker concentrations are measured in the divertor deposits. They are in the range 0.4-1.2% of the source concentration, with moderate poloidal variation.

  15. Reprocessing of {sup 10}B-contaminated {sup 10}Be AMS targets

    Simon, K.J., E-mail: ksz@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee NSW 2232 (Australia); Pedro, J.B. [Institute of Marine and Antarctic Studies, Private Bag 129, Hobart TAS 7001 (Australia); Antarctic Climate and Ecosystems Cooperative Research Centre, Private Bag 80, Hobart TAS 7001 (Australia); Smith, A.M.; Child, D.P.; Fink, D. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee NSW 2232 (Australia)

    2013-01-15

    {sup 10}Be accelerator mass spectrometry (AMS) is an increasingly important tool in studies ranging from exposure age dating and palaeo-geomagnetism to the impact of solar variability on the Earth's climate. High levels of boron in BeO AMS targets can adversely impact the quality of {sup 10}Be measurements through interference from the isobar {sup 10}B. Numerous methods in chemical sample preparation and AMS measurement have been employed in order to reduce the impact of excessive boron rates. We present details of a method developed to chemically reprocess a set of forty boron-contaminated BeO targets derived from modern Antarctic ice. Previously, the excessive boron levels in these samples, as measured in an argon-filled absorber cell preceding the ionisation detector, had precluded routine AMS measurement. The procedure involved removing the BeO + Nb mixture from the target holders and dissolving the BeO in hot concentrated H{sub 2}SO{sub 4}. The solution was then heated with HF to remove the boron as volatile BF{sub 3} before re-precipitating as Be(OH){sub 2} and calcining to BeO. This was again mixed with niobium and pressed into fresh target holders. Following reprocessing, the samples gave boron rates reduced by 10-100 Multiplication-Sign , which were sufficiently low and similar to previous successful batches of ice core, snow and associated blank samples, thus allowing a successful {sup 10}Be measurement in the absence of any boron correction. Overall recovery of the BeO for this process averaged 40%. Extensive testing of relevant processing equipment and reagents failed to determine the source of the boron. As a precautionary measure, a similar H{sub 2}SO{sub 4} + HF step has been subsequently added to the standard ice processing method.

  16. Radon concentration measurements in therapeutic spring water

    It is believed that people undergoing a curative cycle in a given spa, may receive a dose in the range of 400 mSv/year which is many times the average annual dose so that their risk of lung cancer may increase by 3% or more. To determine the risk due to the natural radioactivity, of the most frequented spas in Budapest (H), we selected four and some others located on the country side being of particular interest. Results of the radon concentration in spring water are presented, with the evidence that some spas have a high radon concentration. We conclude that patients receiving treatment may be exposed to an additional dose in the range of 29-76 mSv/year that at the bronchia could be between 445-1182 mSv/year. (authors). 6 refs., 2 figs., 2 tabs

  17. New seeding methodology for gas concentration measurements.

    Chan, Qing N; Medwell, Paul R; Dally, Bassam B; Alwahabi, Zeyad T; Nathan, Graham J

    2012-07-01

    This paper presents the first demonstration of the pulsed laser ablation technique to seed a laminar non-reacting gaseous jet at atmospheric pressure. The focused, second harmonic from a pulsed Nd : YAG laser is used to ablate a neutral indium rod at atmospheric pressure and temperature. The ablation products generated with the new seeding method are used to seed the jet, as a marker of the scalar field. The neutral indium atoms so generated are found to be stable and survive a convection time of the order of tens of seconds before entering the interrogation region. The measurements of planar laser-induced fluorescence (PLIF) with indium and laser nephelometry measurements with the ablation products are both reported. The resulting average and root mean square (RMS) of the measurements are found to agree reasonably well although some differences are found. The results show that the pulsed laser ablation method has potential to provide scalar measurement for mixing studies. PMID:22710315

  18. Erosion of the Eastern United States observed with 10Be

    The problem of identifying areas of accelerated erosion in a dynamic landscape is complicated. The rarity of the stable isotope 9Be, allows 10Be to be detected with accelerator mass spectrometry in natural materials at extremely low levels. The affinity of Be for the components of soil and sediment is sufficiently high that it is effectively immobilized on contact, thereby allowing 10Be to function as a tracer of sediment transport. To a good approximation all the 10Be transport out of a drainage basin is on the sediment leaving it. The ratio of the 10Be carried from the basin by the sediment to that incident upon it, called the erosion index, has been determined for 48 drainage basins within the same physiographic province. The data allow an estimate of the erosion index for the pre-colonial Piedmont, which then allows the precolonial sediment yield to be calculated. A number of basins have also been examined world wide with similar conclusions derived. An important deviation from the rule is noted for rivers that erode large regions of loess, such as the Mississippi, Hwang Ho, and Yangtze. Large aeolian deposits were laid down during the ice age in these basins, deposits that brought inherited 10Be with them and that are easily eroded. (author)

  19. Microwave Measurements of Low Pulp Concentration in Papermaking Process

    Nakayama, Shigeru

    1994-06-01

    A method of microwave measurements of low pulp concentrations in the papermaking process is developed using a coaxial cavity resonator with an inner slot antenna. We measure the attenuation of the resonant peak of the cavity resonator which is related to the pulp concentration. The pulp concentration up to 10.1% is measured, and then the linear relationship between the attenuation and low pulp concentrations down to 0.6% is determined. By this method, a low pulp concentration can be measured within the standard deviation of 0.03% by linear approximation.

  20. SOLAR WIND IMPLANTATION MODEL FOR 10Be IN CALCIUM-ALUMINUM INCLUSIONS

    We propose a model for the incorporation of 10Be within calcium-aluminum inclusions (CAIs) in primitive carbonaceous meteorites. In this model, 10Be is produced by energetic particle reactions in the proto-solar atmosphere of a more active proto-Sun characterized by energetic particle fluxes higher than contemporary particle fluxes. This 10Be is incorporated into the solar wind that is then implanted into CAI precursor material. This production mechanism is operational in the contemporary solar system implanting 10Be in lunar materials. The contemporary production rate of 10Be at the surface of the Sun is ∼0.1 10Be cm-2 s-1. Scaling up the contemporary 10Be production in the proto-Sun by a factor of 105 would increase the production rate to 10410Be cm-2 s-1. Using this enhanced production value in conjunction with refractory mass inflow rates at 0.06 AU from the proto-Sun we model 10Be concentrations in CAI precursors. We calculate the content of solar-wind-implanted 10Be would have been of the order of 101210Be g-1 in CAIs, consistent with initial10Be content found from boron-beryllium isotopic systematics in CAIs.

  1. Loess 10Be evidence for an asynchronous Brunhes-Matuyama magnetic polarity reversal

    Zhou, W.; Beck, W.; Kong, X.; An, Z.; Qiang, X.; Wu, Z.; Xian, F.; Ao, H.

    2015-12-01

    In Chinese loess the Brunhes-Matuyama (B-M) geomagnetic reversal appears to occur about 25 ka prior to the established axial dipole reversal age found in many marine sediments, i.e., in Chinese loess this magnetic reversal boundary is found in glacial loess unit L8 which is thought to be correlated with Marine Isotope Stage 20 (MIS 20), in marine sediment records, however, this boundary is commonly found in interglacial period of MIS 19[1-2], leading to the debate on uncertainties of paleoclimatic correlation between the Chinese loess-paleosol sequences and marine sediments[3-5]. Based on this issue, here we propose to use the cosmogenic 10Be to address this conundrum. 10Be is a long-lived radionuclide produced in the atmosphere by cosmic ray spallation reactions and carried to the ground attached to aerosols. Its atmospheric production rate is inversely proportional to the geomagnetic field intensity [6]. This allows us to reconstruct past geomagnetic field intensity variations using 10Be concentrations recorded in different sedimentary archives. We carried out both the 10Be studies and paleogeomagnetic measurements in Luochuan and Xifeng sections in Chinese Loess Plateau. Both loess profiles show that 10Be production rate was at a maximum-an indication of the dipole field reversal-at ca. 780 ± 3 ka BP., in paleosol unit S7 corresponding to MIS 19, proving that the timing of B-M reversal recorded in Chinese loess is synchronous with that seen in marine records [1]. These results reaffirmed the conventional paleoclimatic correlation of loess-paleosol sequences with marine isotope stages and the standard loess timescale as correct. However, it is ~25 ka younger than the age (depth) of the paleogeomagnetic measurements, which show that the B-M boundary is in L8 in these two Chinese loess-paleosol sequences, demonstrating that loess magnetic overprinting has occurred. 1.Tauxe, L., et al., 1996, EARTH PLANET SC LETT, 140, 133-1462.Zhou, L.P., and Shackleton, 1999

  2. Cosmogenic nuclides 7Be and 10Be in rains collected in Tokyo

    Concentrations of cosmogenic nuclides 7Be and 10Be in rains collected in Tokyo during the last 20 years were determined by γ-ray spectrometry and accelerator mass spectrometry. For the seasonal variation, the highest values for 10Be flux and 10Be/7Be ratio were observed in spring, February to April, and they decreased till the lowest values in autumn. On the other hand, there were not so clear feature for 7Be flux. These feature were caused by the transport of stratospheric air with high 10Be concentration into the troposphere. The annual fluxes for 7Be and 10Be change cyclic, and the average for 7Be and 10Be were ∼3 and ∼10 (x10-2 atom cm-2 s-1) with ±50% and ±30% deviation, respectively. Comparing to the sunspot number as the index of cosmic ray intensity, the annual 7Be flux was anti-correlated, and also the annual 10Be flux was anti-correlated with two years delay. This imply that the most part of 7Be atoms deposited in Tokyo were produced in the troposphere, and the fairly large part of 10Be atoms deposited in Tokyo were produced in the stratosphere. (author)

  3. Study on utilizing ultrasonic for measurement of sediment concentration distribution

    JiaChunjuan; TangMaoguan

    1998-01-01

    In the course of sedimentation research, the measurement of sediment concentration and its distribution is very important. At present, most traditional methods are arduous and cannot measure the sediment timely and successively. In order to seek the new measurement method,the paper reports utilizing ultrasonic measurement. When ultrasonic wave spreads along the depth in aqueous suspensions, the scatter intensity of sediment particles changes the depth and sediment concentration. Based on this principle,

  4. Analysis of longitudinal momentum distribution of 10Be in 9Be(11Be, 10Be)X reaction

    We have analyzed the longitudinal momentum distribution of 10Be fragment coming from one neutron stripping from 11Be on 9Be target at 60AMeV beam energy within the framework of zero and first order eikonal approximation. It has been found that the inclusion of first order correction term in the eikonal approximation results in a substantial improvement in the matching between the predicted and experimental results especially in tail region of the spectrum. (author)

  5. Novel Fiber Optic Fluorometer for the Measurement of Alga Concentration

    2001-01-01

    A novel fluorometer based on fiber optics is briefly introduced for the measurement of alga concentration. Both the exciting light and the fluorescence from alga chlorophyll are transmitted along a fiber cable. By this way, we can get alga concentration by measuring its chlorophyll-a fluorescence intensity. The experiment results show that this instrument is characterized by good sensitivity, linearity and accuracy.

  6. Model-based constraints on interpreting 20th century trends in ice core 10Be

    Field, Christy V.; Schmidt, Gavin A.

    2009-06-01

    Beryllium-10 ice-core records are useful for understanding solar magnetic field changes over time, and in particular over the 20th century, during which there are a variety of relevant observations. However, differences between 10Be snow concentration records from different locations complicate the process of developing a coherent understanding of changes in cosmogenic isotope production. We use the Goddard Institute for Space Studies ModelE general circulation model to simulate the production and transport of beryllium isotopes for this time period. We compare our results with surface air observations, and with ice-core records from Dye 3, Taylor Dome, and South Pole. We find that unforced weather-related (internal) variability causes modeled trends in 10Be snow concentration to vary from the ensemble mean by 50% and greater at all three ice-core locations. Lower levels of internal variability at Taylor Dome and South Pole relative to Dye 3 make the simulated 10Be values at these locations better estimates of the ensemble-mean trend in 10Be snow concentration. In addition, the ensemble mean concentration trend at Dye 3 was significantly different from the expected modeled trend based on applied production changes alone. Overall, the results imply that during the 20th century, 10Be data from multiple cores are likely to be required to make meaningful inferences about 10Be production changes. The model simulations imply that data from Antarctica are likely to be more robust.

  7. Measuring the Degree of Market Concentration in Thailand Insurance Industry

    Sivalap Sukpaiboonwat; Chucheep Piputsitee; Arunee Punyasavatsut

    2014-01-01

    This paper investigates market structure of life insurance and non-life insurance industry in Thailand. This paper uses the Concentration Ratio and the Herfindahl-Hirschman Index to measure the degree of market concentration. The paper also analyzes various data from all type of insurance premium, balance sheet and income statement to measure the concentration and competition trend. An analysis of life insurance premium, group market is unconcentrated where as ordinary and industry markets ar...

  8. Cosmic ray event of A.D. 774-775 shown in quasi-annual 10Be data from the Antarctic Dome Fuji ice core

    Miyake, Fusa; Suzuki, Asami; Masuda, Kimiaki; Horiuchi, Kazuho; Motoyama, Hideaki; Matsuzaki, Hiroyuki; Motizuki, Yuko; Takahashi, Kazuya; Nakai, Yoichi

    2015-01-01

    content in tree rings and 10Be concentration records in polar ice core provide information about past cosmic ray intensities. The A.D. 774-775 cosmic ray event has been identified by 14C measurement in several tree rings from all over the world. Although the quasi-decadal 10Be Dome Fuji data in the Antarctic ice core also shows a sharp peak around A.D. 775, annual 10Be variations in the Dome Fuji core or in other cores have not been revealed. We have measured quasi-annual 10Be concentrations from approximately A.D. 763-794 in the Dome Fuji ice core, and detected a clear increase (~80% above the baseline) in 10Be concentration around A.D. 775. However, an accurate height of this increase is not straightforwardly estimated due to the background variation in 10Be concentration. The 10Be increase can be due to the same cosmic ray event as shown in the 14C content in A.D. 774-775.

  9. High-resolution authigenic 10Be/9Be records : A proxy indicator of the past geomagnetic field variability

    Carcaillet, J.; Thouveny, N.; Bourlès, D. L.

    2003-04-01

    At global scale, the synchronicity of abnormal directions of the paleomagnetic field and minimum intensities supports the hypothesis of a relationship between the occurrence of excursions and/or polarity changes and the collapse of the dipolar component. We present quantitative evaluations of relationships between 10Be production rate variations and geomagnetic events using high resolution authigenic 10Be/9Be ratios and continuous paleointensity records measured in three marine sediment sequences located on the Portuguese margin, (MD95-2042 and MD95-2040), and in the Western Pacific, (MD97-2140). Since 10Be concentrations measured in marine sediments not only depend on 10Be production rates but also on oceanic and sedimentary effects, authigenic (i.e. adsorbed onto particles from the water column) 10Be concentrations were normalized to their related authigenic 9Be concentrations in order to account for these disturbing effects on the sedimentation rate as well as on the chemical and granulometric composition of the sediments. Due to their different sources, only the soluble form of both beryllium isotopes may indeed have been homogenized in the water column before deposition in the sediment. The measured 10Be/9Be ratios increase significantly at all identified excursions and reversals, associated with decreased paleointensities, consistently with the expected relationship between magnetic moment and cosmic ray flux (Q/Qo=(M/Mo)-1/2). Our results confirm the global occurrence of well-recognized and well-dated phases of low geomagnetic moments associated to well known geomagnetic excursions, short events or polarity reversals that occurred between 0 and 300 ka BP and between 0.6 and 1.3 Ma BP: the Laschamp excursion, the Blake event, the Jamaica/Pringle falls excursion, the Brunhes-Matuyama Reversal, the upper and lower Jaramillo transitions and the Cobb Mountain event. They strengthen the validity of recently reported excursions: Icelandic basin, Calabrian Ridge 0

  10. Testing the potential of 10Be in varved sediments from two lakes for solar activity reconstruction

    Czymzik, Markus; Muscheler, Raimund; Brauer, Achim; Adolphi, Florian; Ott, Florian; Kienel, Ulrike; Dräger, Nadine; Slowinski, Michal; Aldahan, Ala; Possnert, Göran

    2015-04-01

    The potential of 10Be in annually laminated (varved) lake sediments for solar activity reconstruction is, to date, largely unexplored. It is hypothesized that 10Be contents in sediments from well-chosen lakes reflect the solar induced atmospheric production signal. The varved nature of these archives provides the chance to establish solar activity time-series with very high temporal precision. However, so far solar activity reconstruction from 10Be in varved lake sediments is hampered due to a lack of detailed knowledge of the process chain from production in the atmosphere to deposition on the lake floor. Calibrating 10Be time-series from varved lake sediments against complementary proxy records from the same sediment archive as well as instrumental meteorological and solar activity data will allow a process-based understanding of 10Be deposition in these lakes and a quantitative evaluation of their potential for solar activity reconstruction. 10Be concentration and flux time-series at annual resolution were constructed for the period 1983 to 2007 (approx. solar cycles 22 and 23) conducting accelerator mass spectrometry and varve chronology on varved sediments of Lakes Tiefer See and Czechowski, located on an east-west transect at a distance of about 450 km in the lowlands of northern-central Europe. 10Be concentrations vary between 0.9 and 1.8*108atoms/g, with a mean of 1.3*108atoms/g in Lake Tiefer See and between 0.6 and 1.6*108atoms/g, with a mean of 1*108atoms/g in Lake Czechowski. Calculated mean 10Be flux is 2.3*108atoms/cm2/year for Lake Tiefer See and 0.7*108atoms/cm2/year for Lake Czechowski. Calibrating the 10Be time-series against corresponding geochemical μ-XRF profiles, varve thickness and total organic carbon records as well as precipitation data from the nearby stations Schwerin for Lake Tiefer See and Koscierzyna for Lake Czechowski and a neutron monitor record of solar activity suggests (1) a complex interaction of varying processes influencing

  11. The cosmogenic radionuclides 26Al and 10Be as a dating tool for climate archives

    Full text: Polar ice is a unique archive of the earth's climate history. Crucial for the interpretation of the information contained in the ice is an accurate dating. Currently, all methods for dating rely on a more or less undisturbed stratigraphy of the ice, which cannot necessarily be assumed for the ice layers close to the bottom. Using the two cosmogenic radionuclides 26Al and 10Be (half-life 0.7 and 1.5 Ma, respectively) absolute dating of ice may become possible: Due to the different half-lives, the change of the 26Al/10Be isotopic ratio can be used as a clock. The extremely low abundance of both isotopes requires measurement by accelerator mass spectrometry (AMS). In order to apply the 26Al/10Be dating method, analytical challenges have to be overcome but also the sources of 10Be and 26Al and their atmospheric transport have to be well understood. In particular, there may be differences in the sources of 26Al and 10Be which could seriously limit the applicability of 26Al/10Be as a dating tool. In addition, the long half-lives of 26Al and 10Be require a high precision measurement for dating, which is a technical challenge, primarily due to the very low abundance of 26Al. First measurements of atmospheric 26Al and 10Be have been carried out at the Vienna Environmental Research Accelerator (VERA) of the University of Vienna. We report here on the measurements as well as on the implications for sources and transport of 26Al and 10Be and on the feasibility of 26Al/10Be as a dating tool. (author)

  12. Combined measurements of velocity and concentration in experimental turbidity currents

    Felix, M.; Sturton, S.; Peakall, J.

    2005-08-01

    Three different sets of experimental turbidity currents were run in which velocity and concentration were measured simultaneously, for several different heights above the bed. One set with cohesive sediment had an initial volumetric concentration of 16% kaolinite, and the other two sets with non-cohesive sediment had concentrations of 28% and 4% silica flour. Velocity was measured at 104-122 Hz using an Ultrasonic Doppler Velocimetry Profiler and concentration was measured at 10 Hz using an Ultrasonic High Concentration Meter. The similarity of changes in velocity and concentration at the same measurement heights are described and it is shown that the similarity depends on flow concentration and position in the flow. The measurements are analysed using cross-correlations and wavelet analysis. Velocity measurements are compared with analytical solutions for flow around a semisphere and flow around a half body. Measurements and analyses indicate that turbulence is diminished by stratification, decoupling of regions where turbulence is generated and by reduction of vertical flow in the turbidity currents.

  13. Measured and calculated NO2 concentrations in Amsterdam in 2008

    Calculations using the Dutch standard calculation method for air quality in urban streets performed for 38 streets in Amsterdam in 2008 yield, on average, lower Nitrogen dioxide concentrations than measurements at those locations. This follows from research by the RIVM and the Public Health Service of Amsterdam (GGD Amsterdam). The average difference between measured and calculated concentrations is 11 %. At measuring locations of the National Air Quality Measuring Network in the Netherlands no significant underestimation of concentrations by the model is observed. The research was performed by the Dutch ministry of Housing, Spatial Planning en the Environment (VROM). The air quality in the streets that were investigated is mainly determined by emissions from local traffic. The measurements have been performed during thirteen periods of four weeks each, using so called 'Palmes' diffusion tubes. These measurements have been calibrated using the European reference method that is operational in the permanent measuring stations of the GGD Amsterdam. The calculations were performed using the geometry of the roads and information of the traffic at the measuring locations. Part of the differences can be explained, as some locations are not within the scope of the model. In these situations the model is known to perform slightly less. Apart from local traffic, other sources, like shipping, also contribute to the NO2 background concentrations in streets in Amsterdam. Sources that have only globally been included in the calculation of this background concentration may influence concentrations at specific locations. Further studies on this subject will be conducted in 2010.

  14. Potentials and pitfalls of depth profile (10Be), burial isochron (26Al/10Be) and palaeomagnetic techniques for dating Early Pleistocene terrace deposits of the Moselle valley (Germany)

    Rixhon, Gilles; Cordier, Stéphane; May, Simon Matthias; Kelterbaum, Daniel; Szemkus, Nina; Keulertz, Rebecca; Dunai, Tibor; Binnie, Steven; Hambach, Ulrich; Scheidt, Stephanie; Brueckner, Helmut

    2016-04-01

    Throughout the river network of the Rhenish Massif the so-called main terraces complex (MTC) forms the morphological transition between a wide upper palaeovalley and a deeply incised lower valley. The youngest level of this complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature; it is often used as a reference level to identify the beginning of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). Although the main terraces are particularly well preserved in the lower Moselle valley, a questionable age of ca. 800 ka is assumed for the YMT, mainly based on the uncertain extrapolation of controversially interpreted palaeomagnetic data obtained in the Rhine valley. In this study, we applied terrestrial cosmogenic nuclide (TCN) dating (10Be/26Al) and palaeomagnetic dating to Moselle fluvial sediments of the MTC. To unravel the spatio-temporal characteristics of the Pleistocene evolution of the valley, several sites along the lower Moselle were sampled following two distinct TCN dating strategies: depth profiles where the original terrace (palaeo-) surface is well preserved and did not experience a major post-depositional burial (e.g., loess cover); and the isochron technique, where the sediment thickness exceeds 4.5-5 m. One terrace deposit was sampled for both approaches (reference site). In addition, palaeomagnetic sampling was systematically performed in each terrace sampled for TCN measurements. The TCN dating techniques show contrasting results for our reference site. Three main issues are observed for the depth profile method: (i) an inability of the modeled profile to constrain the 10Be concentration of the uppermost sample; (ii) an overestimated density value as model output; and (iii) a probable concentration steady state of the terrace deposits. By contrast, the isochron method yields a burial age estimate of 1.26 +0.29/-0.25 Ma, although one sample showed a depleted 26Al/10Be ratio

  15. Measuring the Degree of Market Concentration in Thailand Insurance Industry

    Sivalap Sukpaiboonwat

    2014-01-01

    Full Text Available This paper investigates market structure of life insurance and non-life insurance industry in Thailand. This paper uses the Concentration Ratio and the Herfindahl-Hirschman Index to measure the degree of market concentration. The paper also analyzes various data from all type of insurance premium, balance sheet and income statement to measure the concentration and competition trend. An analysis of life insurance premium, group market is unconcentrated where as ordinary and industry markets are concentrated. As for the life insurance balance sheet and income statement are concentrated market. An analysis of non-life insurance premium, fire, marine and transportation and automobile markets are unconcentrated. As for the non-life insurance balance sheet and income statement are unconcentrated market. In terms of the same sub-categorized product, personal accident and health insurance have difference concentrate degree. Personal accident in life insurance is near monopoly and highly concentrated market while personal accident in non-life insurance is loose oligopoly and moderate concentrated market. Health insurance in life and non-life insurance are tight oligopoly and concentrated market. The results conclude that the life insurance industry is more concentrated than the non-life insurance industry. In both segments of the insurance market, as well as in the overall insurance sector, there is a downward trend in market concentration, which indicates the success of the competition promoting process which allows a greater and better choice for customers.

  16. Module for measurement of CO2 concentration in exhaled air

    Puton, Jaroslaw; Palko, Tadeusz; Knap, Andrzej; Jasek, Krzysztof; Siodlowski, Boguslaw

    2003-09-01

    The objective of this work consists in working out of a detection module for capnography (carbon dioxide concentration measurement in anaesthesiology and intensive care). The principle of operation of the module consists of the NDIR method. The basic assumption for construction of this model was using of directly modulated thermal IR source in it. A few models of IR sources were worked out. Their heaters were made from thick platinum layers and foil. Limits of modulation frequency for IR sources were greater than 30 Hz. The detection module consists of an optical part, analogue electronics and microprocessor system with a suitable program. The time dependent concentration of CO2, end tidal concentration of CO2, mean concentration of N2O and breath frequency are output values of the detection module. Measurements are executed 30 times per second. The accuracy of CO2 concentration measurement equals to 5%.

  17. Uncertainty evaluation in radon concentration measurement using charcoal canister

    Active charcoal detectors are used for testing the concentration of radon in dwellings. The method of measurement is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. The contributions to the final measurement uncertainty are identified, based on the equation for radon activity concentration calculation. Different methods for setting the region of interest for gamma spectrometry of canisters were discussed and evaluated. The obtained radon activity concentration and uncertainties do not depend on peak area determination method. - Highlights: • Measurement uncertainty budget for radon activity concentration established. • Three different methods for ROI selection are used and compared. • Recommend to use one continuous ROI, less sensitive to gamma spectrometry system instabilities

  18. Measurement of radon activity concentrations in air of Tuzla city

    The survey was conducted over one year in the area of Tuzla city and its surrounding. At the measuring locations there were registered Daily and seasonal variations in outdoor radon concentration were observed, with average values lying within the region of 9 - 30 Bq/m3. The results of the measurements will be included in the concentration map of radon activity in Bosnia and Herzegovina, which is under preparation. (P.A.)

  19. Measurements of radon concentrations in Spa waters in Amasya, Turkey

    Yigitoglu, I.; Oner, F.; Yalim, H. A.; Ucar, B.

    2016-04-01

    The aim of this study is to determine the radon concentrations in thermal waters in the Amasya basin in Turkey and to explore the relationship between radon anomalies and active geological faults. The radon concentration measurements were performed in four thermal Spas around Amasya basin. The water samples were collected from tap waters in thermal water sources. The obtained radon concentrations ranged from 0.15 ± 0.12 to 0.71 ± 0.32 BqL-1 for Spa waters. The relationship between the radon concentration anomalies and earthquakes that occurred in the sampling period are discussed.

  20. Traceable measurements of the activity concentration in air

    Paul, A; Forkel-Wirth, Doris; Müller, A; Marcos, A

    2002-01-01

    The nuclear reactions induced by high energetic protons in heavy targets such as UC/sub 2/ and ThC cause a particular, complex radiation protection task at facilities like ISOLDE: the measurement of a mixture of different isotopes of the radioactive noble gas radon and the radon progenies in air. The knowledge of their respective activity concentration is fundamental for exposure assessments. Due to the complex mixture of activity concentrations in air, its precise determination is quite difficult. Therefore, a new procedure for taking reference samples was developed and implemented for the traceable measurement of the activity concentration of radioactive ions (e.g., radon progenies) in air. This technique is combined by measuring alpha -particles with a multi-wire ionization chamber for the parallel on-line determination of the activity concentration of different radon isotopes. (10 refs).

  1. Cosmogenic 10Be Depth Profile in top 560 m of West Antarctic Ice Sheet Divide Ice Core

    Welten, K. C.; Woodruff, T. E.; Caffee, M. W.; Edwards, R.; McConnell, J. R.; Bisiaux, M. M.; Nishiizumi, K.

    2009-12-01

    Concentrations of cosmogenic 10Be in polar ice samples are a function of variations in solar activity, geomagnetic field strength, atmospheric mixing and annual snow accumulation rates. The 10Be depth profile in ice cores also provides independent chronological markers to tie Antarctic to Greenland ice cores and to tie Holocene ice cores to the 14C dendrochronology record. We measured 10Be concentrations in 187 samples from depths of 0-560 m of the main WAIS Divide core, WDC06A. The ice samples are typically 1-2 kg and represent 2-4 m of ice, equivalent to an average temporal resolution of ~12 years, based on the preliminary age-depth scale proposed for the WDC core, (McConnell et al., in prep). Be, Al and Cl were separated using ion exchange chromatography techniques and the 10Be concentrations were measured by accelerator mass spectrometry (AMS) at PRIME lab. The 10Be concentrations range from 8.1 to 19.1 x 10^3 at/g, yielding an average of (13.1±2.1) x 10^3 at/g. Adopting an average snow accumulation rate of 20.9 cm weq/yr, as derived from the age-depth scale, this value corresponds to an average 10Be flux of (2.7±0.5) x 10^5 atoms/yr/cm2. This flux is similar to that of the Holocene part of the Siple Dome (Nishiizumi and Finkel, 2007) and Dome Fuji (Horiuchi et al. 2008) ice cores, but ~30% lower than the value of 4.0 x 10^5 atoms/yr/cm2 for GISP2 (Finkel and Nishiizumi, 1997). The periods of low solar activity, known as Oort, Wolf, Spörer, Maunder and Dalton minima, show ~20% higher 10Be concentrations/fluxes than the periods of average solar activity in the last millennium. The maximum 10Be fluxes during some of these periods of low solar activity are up to ~50% higher than average 10Be fluxes, as seen in other polar ice cores, which makes these peaks suitable as chronologic markers. We will compare the 10Be record in the WAIS Divide ice core with that in other Antarctic as well as Greenland ice cores and with the 14C treering record. Acknowledgment. This

  2. Concentration of Radon Progeny in Air by Alpha Spectrometry Measurement

    The concentration of radon progeny in air has been determined by alpha spectrometry measurement of 214 Po and 318 Po. A known volume of air was passed through a filter, then the alpha activity was directly measured on this filter. (Author) 15 refs

  3. Liver Metabolite Concentrations Measured with 1H MR Spectroscopy

    Ouwerkerk, Ronald; PETTIGREW, RODERIC I.; Gharib, Ahmed M.

    2012-01-01

    In vivo measurement of liver choline concentrations in healthy humans is feasible, and even measurement of glycogen can be achieved in some patients at 3.0 T with point-resolved 1H MR spectroscopy by using navigator-guided synchronization to respiratory motion and state-of-the-art B0 field shimming techniques.

  4. Species concentration measurements using CARS with nonresonant susceptibility normalization

    An investigation of in situ background normalization for obtaining sensitive and accurate concentration measurements with coherent anti-Stokes Raman spectroscopy (CARS) is reported. Flame species concentrations measured with CARS were in good agreement with IR laser absorption measurements of CO in extracted flame gases and with equilibrium calculations. Time-averaged detectivity for CO at the 1000-ppm level was obtained at 1900 K. Background normalization was also shown to be capable of improving CARS pulse-to-pulse signal reproducibility nearly to the shot-noise limit. We consider factors important for concentration measurements with CARS, including laser-induced Stark effects, accuracy of susceptibility calculations, and effects of different laser linewidth models

  5. Control Rights, Pyramids, and the Measurement of Ownership Concentration

    Edwards, Jeremy S.S.; Alfons J. Weichenrieder

    2009-01-01

    Abstract The recent corporate governance literature has emphasised the distinction between control and cash-flow rights but has disregarded measurement issues. Control rights may be measured by immediate shareholder votes, the voting rights as traced through ownership chains, or voting power indices that may or may not trace ownership through chains. We compare the ability of various measures to identify the effects of ownership concentration on share valuation using a German panel...

  6. Quality assurance in accelerator mass spectrometry: Results from an international round-robin exercise for 10Be

    Highlights: ► First round-robin exercise for 10Be with 10 AMS facilities to improve accuracy. ► All data traceable to NIST SRM 4325. ► Multivariate statistical investigations reveal bias, i.e. two distinguished groups. ► Maximum discrepancies of 6–31% between two single facilities depending on ratio. ► Findings should be considered when using AMS data from different facilities. - Abstract: The first international round-robin exercise for the measurement of the long-lived radionuclide 10Be has been conducted. Ten participating accelerator mass spectrometry (AMS) facilities have each measured three samples at the 10−12 to 10−1410Be/9Be level. All results have been made traceable to the NIST SRM 4325 standard to avoid additional discrepancies that arise when different facilities use different calibration materials. Hence, the data concentrates on pure measurement distinctions. Multivariate statistical investigations have been performed to reveal a bias between facilities, i.e. two distinguished groups could be identified. Maximum discrepancies between two single facilities are in the range of 6–31% depending on the absolute 10Be/9Be value. These findings should be considered when comparing 10Be data produced at one AMS facility with that produced at another facility, which is e.g. often the case for in situ 10Be dating studies. Round-robin exercises are a very helpful tool as part of an overall quality assurance scheme to improve the accuracy, and not only the precision, of AMS data.

  7. A preliminary study on the use of (10)Be in forensic radioecology of nuclear explosion sites.

    Whitehead, N E; Endo, S; Tanaka, K; Takatsuji, T; Hoshi, M; Fukutani, S; Ditchburn, R G; Zondervan, A

    2008-02-01

    Cosmogenic (10)Be, known for use in dating studies, unexpectedly is also produced in nuclear explosions with an atom yield almost comparable to (e.g.) (137)Cs. There are major production routes via (13)C(n, alpha)(10)Be, from carbon dioxide in the air and the organic explosives, possibly from other bomb components and to a minor extent from the direct fission reaction. Although the detailed bomb components are speculative, carbon was certainly present in the explosives and an order of magnitude calculation is possible. The (n, alpha) cross-section was determined by irradiating graphite in a nuclear reactor, and the resulting (10)Be estimated by Accelerator Mass Spectrometry (AMS) giving a cross-section of 34.5+/-0.7mb (6-9.3MeV), within error of previous work. (10)Be should have applications in forensic radioecology. Historical environmental samples from Hiroshima, and Semipalatinsk (Kazakhstan) showed two to threefold (10)Be excesses compared with the background cosmogenic levels. A sample from Lake Chagan (a Soviet nuclear cratering experiment) contained more (10)Be than previously reported soils. (10)Be may be useful for measuring the fast neutron dose near the Hiroshima bomb hypocenter at neutron energies double those previously available. PMID:17904707

  8. The active titration method for measuring local hydroxyl radical concentration

    Sprengnether, Michele; Prinn, Ronald G.

    1994-01-01

    We are developing a method for measuring ambient OH by monitoring its rate of reaction with a chemical species. Our technique involves the local, instantaneous release of a mixture of saturated cyclic hydrocarbons (titrants) and perfluorocarbons (dispersants). These species must not normally be present in ambient air above the part per trillion concentration. We then track the mixture downwind using a real-time portable ECD tracer instrument. We collect air samples in canisters every few minutes for roughly one hour. We then return to the laboratory and analyze our air samples to determine the ratios of the titrant to dispersant concentrations. The trends in these ratios give us the ambient OH concentration from the relation: dlnR/dt = -k(OH). A successful measurement of OH requires that the trends in these ratios be measureable. We must not perturb ambient OH concentrations. The titrant to dispersant ratio must be spatially invariant. Finally, heterogeneous reactions of our titrant and dispersant species must be negligible relative to the titrant reaction with OH. We have conducted laboratory studies of our ability to measure the titrant to dispersant ratios as a function of concentration down to the few part per trillion concentration. We have subsequently used these results in a gaussian puff model to estimate our expected uncertainty in a field measurement of OH. Our results indicate that under a range of atmospheric conditions we expect to be able to measure OH with a sensitivity of 3x10(exp 5) cm(exp -3). In our most optimistic scenarios, we obtain a sensitivity of 1x10(exp 5) cm(exp -3). These sensitivity values reflect our anticipated ability to measure the ratio trends. However, because we are also using a rate constant to obtain our (OH) from this ratio trend, our accuracy cannot be better than that of the rate constant, which we expect to be about 20 percent.

  9. 10Be variation in surficial sediments of the Central Indian Basin

    Distribution of 10Be in systematically collected (degree x degree interval at 10 to 16 deg. S; 73.5 to 76.5 deg. E) surficial siliceous ooze, siliceous clay and pelagic clay sediments (top 2 cm) from the abyssal Central Indian Basin and the Andaman Sea is used to evaluate sources and to decipher the transport pathways of sediment particles, demarcate sediment depocenters and erosional areas. While 10Be concentrations display a wide variation (0.12-5.56 x 109 atoms g-1) with an average of 3.58 x 109 atoms g-1 in the Central Indian Basin, the values in the Andaman Sea are uniform with an average of 1.49 x 109 atoms g-1. The 10Be/9Be values in the Central Indian Basin sediments range between 0.06 and 2.99 x 10-8 atoms atoms-1 and average to ∼1.56 x 10-8 atoms atoms-1. Correlation of 10Be data with some selected major (Al, Mn, Ti) and trace (Rb and Ba) elements suggest that large part of the isotope has been supplied through direct atmospheric fallout from the water column and minor part from lithogenic detrital flux. Significantly lower 10Be accumulation rates in the Central Indian Basin and an order of magnitude higher in the Andaman Sea sediments compared to the estimated global average production rates indicate removal of the isotopes at the continental margins. Bottom topography seems to exert control on local 10Be variation, where sediments deposited in valleys or topographic depressions contain higher 10Be concentrations in contrast to the probably erosion-dominated areas at the slopes and troughs

  10. Remote atomic information concentration without Bell-state measurement

    Wu Zhen-Zhen; Fang Mao-Fa

    2006-01-01

    This paper proposes a scheme for information concentration of two remote two-level atoms in cavity QED. This scheme does not involve the Bell-state measurement. During the interaction between atom and cavity, the cavity frequency is large-detuned from the atomic transition frequency, thus the scheme is insensitive to both the cavity decay and the thermal field. This idea can directly be generalized in the case of multi-atom information concentration.

  11. A measure of the concentration of rare events.

    Prieto Curiel, Rafael; Bishop, Steven

    2016-01-01

    We introduce here an index, which we call the Rare Event Concentration Coefficient (RECC), that is a measure of the dispersion/concentration of events which have a low frequency but tend to have a high level of concentration, such as the number of crimes suffered by a person. The Rare Event Concentration Coefficient is a metric based on a statistical mixture model, with a value closer to zero meaning that events are homogeneously distributed, and a value closer to one meaning that the events have a higher degree of concentration. This measure may be used to compare the concentration of events over different time periods and over different regions. Other traditional approaches for the dispersion/concentration of a variable tend to be blind to structural changes in the pattern of occurrence of rare events. The RECC overcomes this issue and we show here two simple applications, first by using the number of burglaries suffered in Netherlands and then by using the number of volcanic eruptions in the world. PMID:27577532

  12. Measurements in Concentrated Sun using a Remote Controlled Robot

    Dan Floroian

    2013-04-01

    Full Text Available Nowdays, using the concentrated sunlight is a big issue because the amount of energy is very high and the light is concentrated in a very small area. The main problem in this situation is the heating, and in order to make safe measurements a remote controlled robot is needed. After that, a remote controlled robot will assume the duty of protect the measured sample and to expose it for a precise time to the concentrated sun in order to reduce heating of the sample. For easy operating, and for automatize the process, all the duties, starting with initial conditions, continuing with triggering the measurements, and conditioning the signals and finalizing with data saving must be assured by the robot.

  13. Rapid Ammonia Deposition Measured Near Concentrated Animal Feeding Operations

    Stanton, L. G.; Pan, D.; Sun, K.; Golston, L.; Tao, L.; Zondlo, M. A.

    2014-12-01

    Concentrated animal feeding operations (CAFOs) emit massive amounts of ammonia (NH3) to the atmosphere. Current measurements of NH3 are generally conducted far away from the sources (satellites, airplanes, etc.). There is insufficient knowledge about the dry deposition rate of NH3 near the sources, which might contribute to the large discrepancies between measured concentrations at CAFOs and those from models. During the 2014 NASA DISCOVER-AQ campaign, we designed a series of tests to measure the deposition rate of NH3 by utilizing a suite of sensors, including a LICOR LI-7700 methane sensor and Princeton University's custom open path NH3 sensor, which was mounted on top of a small SUV. Our mobile sampling technique enables us to follow feedlot emission plumes to see how ambient NH3 concentration decays as gases moves away from the CAFO. The mobile platform is used to perform upwind and downwind sampling to characterize the NH3 emission source. We tracked the change of the enhancement of NH3 concentration relative to the enhancement of CH4 concentration (ΔNH3:ΔCH4), while transecting the plume of individual cattle feedlots. Measured data shows that the high concentration of NH3 seen at the source decreases quickly as one moves further downwind from it. A time constant of approximately ten minutes has been calculated from the decay of the ΔNH3:ΔCH4 ratios while moving away from the sources. We also will compare our measurements with those of NASA's P-3B aerosol measurements to show that the majority must be lost to dry deposition. This rapid deposition suggests that large amounts of NH3 are being deposited in very close proximity to these CAFOs, which is consistent with previous findings of locally high soil pH near NH3 sources. Our results will be used to better characterize nitrogen deposition from cattle feedlots and estimate NH3 lifetime.

  14. Measuring concentrations of volatile organic compounds in vinyl flooring.

    Cox, S S; Little, J C; Hodgson, A T

    2001-08-01

    The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and, consequently, affect mass transfer characteristics. To measure solid-phase concentrations under conditions resembling those in which the material would be installed in an indoor environment, a new technique was developed for measuring VOC concentrations in vinyl flooring (VF) and similar materials. A 0.09-m2 section of new VF was punched randomly to produce -200 0.78-cm2 disks. The disks were milled to a powder at -140 degrees C to simultaneously homogenize the material and reduce the diffusion path length without loss of VOCs. VOCs were extracted from the VF particles at room temperature by fluidized-bed desorption (FBD) and by direct thermal desorption (DTD) at elevated temperatures. The VOCs in the extraction gas from FBD and DTD were collected on sorbent tubes and analyzed by gas chromatography/mass spectrometry (GC/MS). Seven VOCs emitted by VF were quantified. Concentration measurements by FBD ranged from 5.1 microg/g VF for n-hexadecane to 130 microg/g VF for phenol. Concentrations measured by DTD were higher than concentrations measured by FBD. Differences between FBD and DTD results may be explained using free-volume and dual-mobility sorption theory, but further research is necessary to more completely characterize the complex nature of a diffusant in a polymer matrix. PMID:11518293

  15. Measurement of radon concentrations at Super-Kamiokande

    Collaboration, Super-Kamiokade; :; al, Y. Takeuchi et

    1999-01-01

    Radioactivity from radon is a major background for observing solar neutrinos at Super-Kamiokande. In this paper, we describe the measurement of radon concentrations at Super-Kamiokande, the method of radon reduction, and the radon monitoring system. The measurement shows that the current low-energy event rate between 5.0 MeV and 6.5 MeV implies a radon concentration in the Super-Kamiokande water of less than 1.4 mBq/m$^3$.

  16. Measurements of radon concentrations in SPA waters in Amasya, Turkey

    Radon concentration measurements were performed in four spas used for therapy, drinking and irrigation purposes in the Amasya basin in Turkey, during a period of time between January 2009 and May 2010. The measurements were done using commercially available WG-1001 Vacuum Water Degassing System and the AB-5R Radiation Monitor manufactured by Pylon Electronics. The observed radon concentration values ranged from 0.11 to 0.71 Bq L-1. Effective doses from inhalation of radon released from spa waters have been estimated between 0.28 and 1.78 μSv y-1. (authors)

  17. The influence of thoron on instruments measuring radon activity concentration

    Thoron, the isotope 220 of radon, is a radionuclide whose concentration may influence the measurement of the activity concentration of 222Rn in the air. If in the case of continuous and active sampling measuring instruments, using a pump for example, the influence of thoron on radon measurement is obvious and is taken into account in the apparatus, it is often assumed that in the case of a passive sampling, by diffusion through a filter for example, this thoron influence is negligible. This is due to the very short radioactive half-life of thoron, 55.6 s (3.82 d for 222Rn), and the assumption that the diffusion time of thoron in the detection chamber is long enough beside that of the thoron half-life. The objective of this study is to check whether this assumption is true or not for different kinds of commercial electronic apparatus used to measure radon activity concentration from soil to dwellings. First of all, the devices were calibrated in activity concentration of radon, and then they were exposed to a controlled thoron atmosphere. The experiments concerning the thoron aimed to investigate the sensitivity to thoron in the radon measuring mode of the apparatus. Results of these experiments show that all devices have a very quick answer to thoron atmosphere, even though the sensitivities vary from one instrument to another. Results clearly show that this influence on radon measurement due to the thoron is observed also after the exposition because of the decay of 212Pb and its progenies. In conclusion, the sensitivity to thoron in the radon measuring mode depends strongly on the type of instruments. The results of the present investigation show that for some apparatus, the influence of thoron cannot be disregarded especially when measuring radon in soil. (authors)

  18. Outdoor radon concentration measurements: Some correlation with major urban pollutants

    Air pollutants concentration in the urban air strongly depends on the properties of the planetary boundary layer (the lower region of the atmosphere), roughly up to 1 km from Earth's surface. Radioactive radon gas has been recognised by various authors as a valuable natural tracer of transport and dispersion within this layer. To achieve a better comprehension of the urban pollution dynamic in the town of Alessandria, situated in the Po Valley in the north-west of Italy, a system for continuous measurement of radon concentration in outdoor air was experimented. This paper presents the first results obtained: the hourly trend of radon concentration in the diurnal course during different seasons and its correlation with the concentration of the major urban pollutants. (authors)

  19. Outdoor radon concentration measurements: some correlation with major urban pollutants.

    Garbero, V; Dellacasa, G; Bianchi, D; Magnoni, M; Erbetta, L

    2009-12-01

    Air pollutants concentration in the urban air strongly depends on the properties of the planetary boundary layer (the lower region of the atmosphere), roughly up to 1 km from Earth's surface. Radioactive radon gas has been recognised by various authors as a valuable natural tracer of transport and dispersion within this layer. To achieve a better comprehension of the urban pollution dynamic in the town of Alessandria, situated in the Po Valley in the north-west of Italy, a system for continuous measurement of radon concentration in outdoor air was experimented. This paper presents the first results obtained: the hourly trend of radon concentration in the diurnal course during different seasons and its correlation with the concentration of the major urban pollutants. PMID:19906661

  20. Particle trajectories on hillslopes: Implications for particle age and 10Be structure

    Anderson, Robert S.

    2015-09-01

    Many geomorphic systems act as conveyor belts onto which material is loaded at a particular rate and is transported in one direction toward another system that serves as a sink. As the material travels, it ages, it changes in grain size, it accumulates cosmogenic radionuclides, it adsorbs or releases nutrients, and it weathers. Here I address the hillslope conveyor. As many geochemical processes are depth-dependent, the depth history of a particle becomes important to know. I calculate soil particle trajectories in the horizontal-depth plane and address three cases, one in which horizontal speeds decline exponentially with depth, a second in which they are uniform with depth, and a third in which horizontal speeds are also uniform but all profile values are vertically well-mixed. Vertical speeds are governed by continuity in an incompressible medium and by the boundary condition of zero vertical particle speed at the soil surface. Particle trajectories must therefore become surface parallel at the surface. Knowledge of soil particle trajectories allows calculation of residence times and concentration profiles of 10Be in the soil. The results inform strategies for interpretation of nuclide concentrations in soils and stream sediments and for inference of transport rate profiles. In all steady cases, the particle age and 10Be structure are uniform with distance from the divide. When significant vertical gradients in horizontal speed occur, the patterns of particle age and of 10Be concentration are dominated by the depth scale of the transport process. In unmixed cases, the particle age and 10Be concentration in near-surface samples can greatly exceed the vertically averaged values, reflecting the fact that the vertical speeds of particles slow dramatically as they near the surface. In cases in which horizontal speed varies significantly with depth, the vertically averaged concentration of 10Be within the soil can significantly underpredict the mean 10Be concentration

  1. Photopyroelectric measurement of dry matter content in tomato puree concentrates

    Neamtu, C.; Dadarlat, D.; Bicanic, D.D.

    2006-01-01

    The photopyroelectric (PPE) method, in both front and back configuration, was used to measure the thermal effusivity and diffusivity of several tomato puree concentrates. These results were used to construct a calibration curve which was used at a later stage to determine dry matter content of tomat

  2. Measurements of radon activity concentrations in air at Niska spa

    Radon activity concentrations in air were measured in the recreational-tourist center of Niska Banja. Alpha Guard PQ 2000/ MC50 instrumentation (Genitron instruments, Frankfurt) was used. The observed indoor radon concentrations in the air of the Radon Hotel pool lay within the range of 0.980-1.908 kBq/m3 and were directly dependent on the exhalation of radon from thermomineral waters. Radon concentrations were also measured outdoors, at locations for capping thermomineral water, as well as at locations for draining used water from the Radon Hotel pool. Outdoor radon concentrations as high as over 500 Bq/m3 were observed. Gamma dose rates were measured in parallel and found to lie within the range of 72-420 nSv/h. The gamma doses correlated well with the observed radon levels. The largest gamma dose rates in air were measured in the pool of Radon Hotel and at the site where this thermomineral water is being capped

  3. Measurements of indoor radon concentration with CSR detectors

    The measurements of indoor radon concentration in representative dwellings in Shenyang City were made by CSR detectors, and the results were compared with those obtained by the grab sampling technique. It was shown that the results of the latter were 15%-50% less, and CSR detectors were more suitable for the environment radon investigation

  4. Be2D: A model to understand the distribution of meteoric 10Be in soilscapes

    Campforts, Benjamin; Vanacker, Veerle; Vanderborght, Jan; Govers, Gerard

    2016-04-01

    force optimisation allows reliably parameter constraining, resulting in a good agreement between simulated and observed meteoric 10Be concentrations and inventories. Our simulations suggest that meteoric 10Be can be used as a tracer to unravel human impact on soil fluxes when soils have a high affinity to sorb meteoric 10Be.

  5. 10Be in marine sediments: applications in geophysics and palaeo-oceanography

    Two problems are investigated in this study: 1. Cosmogenic isotopes (such as 10Be) are produced by nuclear reactions of cosmic rays with atoms of the earth's atmosphere and uppermost lithosphere. Due to the shielding effect of the earth's magnetic field against cosmic rays the production of cosmogenic nuclides is inversely related to the geomagnetic field intensity. During geomagnetic reversals, when the field intensity is strongly reduced, the production of cosmogenic isotopes should increase. There is no unambiguous evidence yet, whether this increase is reflected in higher concentrations of 10Be at reversal horizons in deep sea sediments. This relationship is analysed in detail across four magnetic reversals. 2. The influence of climatic and paleographic factors on the distribution of 10Be in the ocean is as yet only poorly known. 10Be profiles in deep sea sediments spanning several climatic cycles are used to evaluate the influence of the Quaternary climatic cycles on the distribution of 10Be in oceanic sediments. (author) figs., tabs., refs

  6. AMS of 10Be/9Be and 26Al/27Al at low energies

    The compact ABMs system Tandy (600kV) at ETH Zurich is a versatile facility for the measurement of long-lived radionuclides like 10Be, 26Al, 41Ca, 129I and actinides. Using Helium as stripper gas improves the yield of actinides in charge state 3+ but also has impact on the determination of 10Be and 26Al at low terminal voltages. Carrier-free 10Be/9Be analysis requires a special treatment of the sample material during the chemical preparation and a sensitive measurement of the 9Be current. Exemplary applications of this method performed at the Tandy facility include the dating of a Neogene fossil site and the study of the Brunhes-Matuyama geomagnetic field reversal. (author)

  7. Reusable glucose fiber sensor for measuring glucose concentration in serum

    Cheng-Chih Hsu; Yi-Cheng Chen; Ju-Yi Lee; Chyan-Chyi Wu

    2011-01-01

    We demonstrate a glucose fiber sensor for measuring glucose concentration in serum. High resolution and rapid measurement are achieved through the integration of highly selective enzymes and heterodyne interferometry. The best resolution and response time obtained are 0.14mg/dL and 1.3 s, respectively. The stability of the sensor is also verified by investigating the initial phase variation. Experimental results show that the fiber sensor can be reused more than 10 times.%We demonstrate a glucose fiber sensor for measuring glucose concentration in serum.High resolution and rapid measurement are achieved through the integration of highly selective enzymes and heterodyne interferometry.The best resolution and response time obtained are 0.14 mg/dL and 1.3 s,respectively.The stability of the sensor is also verified by investigating the initial phase variation.Experimental results show that the fiber sensor can be reused more than 10 times.Fiber sensors have attracted considerable attention over the past two decades.Various kinds of fiber sensors have been proposed for measnring specific chemical concentrations[1-8].Most previously reported methods[1-5] involved measuring the variations in fluorescence intensity[2-4] or transmitted light[3,4].Hence,avoiding the inflnence of snrrounding light and the use of expensive photon detection equipment are important requirements.Furthermore,procedures for manufacturing optical biosensors are complicated[3] and qualitv is difficult to control[4]..

  8. Market power in electricity markets: Beyond concentration measures

    The wave of electricity market restructuring both within the US and abroad has brought the issue of horizontal market power to the forefront of energy policy. Traditionally, estimation and prediction of market power has relied heavily on concentration measures. In this paper, the authors discuss the weaknesses of concentration measures as a viable measure of market power in the electricity industry, and they propose an alternative method based on market simulations that take advantage of existing plant level data. The authors discuss results from previous studies they have performed, and present new results that allow for the detection of threshold demand levels where market power is likely to be a problem. In addition, the authors analyze the impact of that recent divestitures in the California electricity market will have on estimated market power. They close with a discussion of the policy implications of the results

  9. Long path DOAS measurements of atmospheric pollutants concentration

    Geiko, Pavel P.; Smirnov, Sergey S.; Samokhvalov, Ignatii V.

    2015-11-01

    A differential optical absorption spectroscopy gas-analyzer consisted of a coaxial telescope, a spectrometer, an analyzer and retroreflector was successfully tested. A high pressure 150-W Xe arc lamp was employed as a light source. In order to record the spectra, a monochrometer with a grating and photodiode array was used. Gas analyzer spectral data bank includes more than 35 moleculas absorbed in UV spectral region. The measured absorption spectra were evaluated by using a least-squares fit to determine the average mixing ratio of each species in the atmosphere. As a result of experiments time series of concentrations of gases polluting the atmosphere were trace measured. Minimally detected concentration on pathlength 480 m is the unit of ppb at the time of accumulation of 2 min. The results of the field test measurements of pollutants in Tomsk city are presented.

  10. Radon concentration measurements in the desert caves of Saudi Arabia

    Beneath the harsh deserts of Saudi Arabia lie dark chambers and complex mazes filled with strange shapes and wondrous beauty. Radon concentration measurements have been carried out in the desert caves of Al-Somman Plateau in the Eastern Province of Saudi Arabia. Passive radon dosimeters, based on alpha particle etch track detectors with an inlet filter, were used in this study. A total of 59 dosimeters were placed in five caves for a period of six months. Out of 59 dosimeters, 37 could be collected for analysis. Measurements showed significant variations in radon concentrations in caves depending upon their natural ventilation. The results of the study show that the average radon concentration in the different caves ranges from 74 up to 451Bqm-3. The average radon concentration in four of the caves was low in the range 74-114Bqm-3. However, one cave showed an average radon concentration of 451Bqm-3. Radon is not a problem for tourists in the majority of caves. However, sometimes it may imply some limitation to the working time of guides

  11. Estimates of CO2 traffic emissions from mobile concentration measurements

    Maness, H. L.; Thurlow, M. E.; McDonald, B. C.; Harley, R. A.

    2015-03-01

    We present data from a new mobile system intended to aid in the design of upcoming urban CO2-monitoring networks. Our collected data include GPS probe data, video-derived traffic density, and accurate CO2 concentration measurements. The method described here is economical, scalable, and self-contained, allowing for potential future deployment in locations without existing traffic infrastructure or vehicle fleet information. Using a test data set collected on California Highway 24 over a 2 week period, we observe that on-road CO2 concentrations are elevated by a factor of 2 in congestion compared to free-flow conditions. This result is found to be consistent with a model including vehicle-induced turbulence and standard engine physics. In contrast to surface concentrations, surface emissions are found to be relatively insensitive to congestion. We next use our model for CO2 concentration together with our data to independently derive vehicle emission rate parameters. Parameters scaling the leading four emission rate terms are found to be within 25% of those expected for a typical passenger car fleet, enabling us to derive instantaneous emission rates directly from our data that compare generally favorably to predictive models presented in the literature. The present results highlight the importance of high spatial and temporal resolution traffic data for interpreting on- and near-road concentration measurements. Future work will focus on transport and the integration of mobile platforms into existing stationary network designs.

  12. Measurement of mean radon concentrations in the Tokai districts

    This paper describes an electrostatic integrating radon monitor designed for the environmental radon monitoring and longterm measurements of mean radon concentrations in outdoor and indoor air. The position of the collecting electrode within the monitor was determined based on the calculation of the internal electric field. The radon exchange rate between the monitor and the outside air through the filter was 0.75 h-1. The exchange rate can make the radon concentration inside the monitor to follow thoroughly the outside concentration. Since the electrostatic collection of RaA+ (218Po+) atoms depends on the humidity of the air, the inside of the monitor was dehumidified with a diphosphorus pentaoxide (P2O5) drying agent which is powerful and dose not absorb radon gas. From the relationship between track density and radon exposure, the calibration factor was derived to be 0.52 ± 0.002 tracks cm-2 (Bq m-3 h)-1. The detection limit of mean radon level is 1.2 Bq m-3 for an exposure time fo 2 months. The mean radon concentrations in various environments were measured through the year using the monitors this developed. The annual mean outdoor radon level in the Tokai districts was 7.0 Bq m-3. The mean radon concentrations was found to vary from 3.5 to 11.7 Bq m-3 depending upon the geographical conditions even in this relatively small region. The annual indoor radon concentrations at Nagoya and Sapporo ranged from 6.4 to 11.9 Bq m-3 and from 15.5 to 121.1 Bq m-3, respectively, with the type of building material and the ventilation rate. The mean radon concentrations in tightly built houses selected at Sapporo are about 10 times as high as those in drafty houses at Nagoya. (author)

  13. Measurement of Alpha Emitters Concentration in Imported Cigarettes

    The aime of this study was to measured the alpha emitters concentration of (15) different kinds of imported cigarettes. the nuclear reaction used U-235(n, f) obtained by the bombardment of U-235 with thermal neutrons from (AmBe)neutron source with thermal flux of(5*103 n.cm-2.s-1). The Results obtained showed the values of the Uranium concentration, and varies from (0.041 ppm) in five stares kind to (2.374ppm) in Machbeth (chocolate) 100's kind. All the result obtained are within the limit levels as given by UNSCAR data

  14. Method and device for measuring the smoke concentration in air

    The patent deals with a method and a device for measuring the smoke concentration in air. In a smoke chamber are located two electrodes, connected to a voltage source for forming a circuit in which a DC current flows. A radioactive radiation source to ionize the air molecules is located in the vicinity of the smoke chamber, so that the number of ionized air molecules which are formed is dependent upon the radiation intensity of the ion source and the concentration of smoke particles in the smoke chamber. The charging voltage will further imply that a cloud of high ion concentration is built up close to the surface of the electrodes. The ion cloud will be discharged capacitively upon a plurality of short voltages pulses applied to the electrodes to thereby result in current pulses substantially greater than the DC current flowing through the chamber. 8 figs

  15. Radon concentration measurements in the AMASRA coal mine, Turkey

    In this study, the results of atmospheric radon measurements that were performed for the Amasra underground coal mine in Zonguldak bituminous coal basin (Turkey) are presented. The radon measurements were performed for 40 days between November 2004 and December 2004 using passive nuclear etched track detectors. The radon concentrations vary from a minimum value 49 Bq m-3 in a site located at +40 m to a maximum value 223 Bq m-3 in a site located at -100 m. Mean concentration is 117 (Bq m-3). This value is well below the action level of 500-1500 Bq m-3 recommended by the International Commission on Radiological Protection (ICRP) (1993). The mean effective dose value for workers of this mine of 3.4 μSv per day was obtained. This result shows that protection against radiological hazards would not be necessary for workers of this mine(2). (authors)

  16. Measurement of Steroid Concentrations in Brain Tissue: Methodological Considerations

    Taves, Matthew D.; Ma, Chunqi; Heimovics, Sarah A.; Saldanha, Colin J.; Soma, Kiran K.

    2011-01-01

    It is well recognized that steroids are synthesized de novo in the brain (neurosteroids). In addition, steroids circulating in the blood enter the brain. Steroids play numerous roles in the brain, such as influencing neural development, adult neuroplasticity, behavior, neuroinflammation, and neurodegenerative diseases such as Alzheimer’s disease. In order to understand the regulation and functions of steroids in the brain, it is important to directly measure steroid concentrations in brain ti...

  17. Measurement of steroid concentrations in brain tissue: methodological considerations

    MatthewDTaves; ColinJSaldanha; KiranKSoma

    2011-01-01

    It is well recognized that steroids are synthesized de novo in the brain (neurosteroids). In addition, steroids circulating in the blood enter the brain. Steroids play numerous roles in the brain, such as influencing neural development, behavior, neuroplasticity, and inflammation. In order to understand the regulation and functions of steroids in the brain, it is important to directly measure steroid concentrations in brain tissue. In this brief review, we discuss methods for the detection an...

  18. Laser metrology in fluid mechanics granulometry, temperature and concentration measurements

    Boutier, Alain

    2013-01-01

    In fluid mechanics, non-intrusive measurements are fundamental in order to improve knowledge of the behavior and main physical phenomena of flows in order to further validate codes.The principles and characteristics of the different techniques available in laser metrology are described in detail in this book.Velocity, temperature and concentration measurements by spectroscopic techniques based on light scattered by molecules are achieved by different techniques: laser-induced fluorescence, coherent anti-Stokes Raman scattering using lasers and parametric sources, and absorption sp

  19. EVIDENCE FOR MULTIPLE SOURCES OF {sup 10}Be IN THE EARLY SOLAR SYSTEM

    Wielandt, Daniel; Krot, Alexander N.; Bizzarro, Martin [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Copenhagen DK-1350 (Denmark); Nagashima, Kazuhide; Huss, Gary R. [Hawai' i Institute of Geophysics and Planetology, University of Hawai' i at Manoa, HI 96822 (United States); Ivanova, Marina A. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow 119991 (Russian Federation)

    2012-04-01

    Beryllium-10 is a short-lived radionuclide (t{sub 1/2} = 1.4 Myr) uniquely synthesized by spallation reactions and inferred to have been present when the solar system's oldest solids (calcium-aluminum-rich inclusions, CAIs) formed. Yet, the astrophysical site of {sup 10}Be nucleosynthesis is uncertain. We report Li-Be-B isotope measurements of CAIs from CV chondrites, including CAIs that formed with the canonical {sup 26}Al/{sup 27}Al ratio of {approx}5 Multiplication-Sign 10{sup -5} (canonical CAIs) and CAIs with Fractionation and Unidentified Nuclear isotope effects (FUN-CAIs) characterized by {sup 26}Al/{sup 27}Al ratios much lower than the canonical value. Our measurements demonstrate the presence of four distinct fossil {sup 10}Be/{sup 9}Be isochrons, lower in the FUN-CAIs than in the canonical CAIs, and variable within these classes. Given that FUN-CAI precursors escaped evaporation-recondensation prior to evaporative melting, we suggest that the {sup 10}Be/{sup 9}Be ratio recorded by FUN-CAIs represents a baseline level present in presolar material inherited from the protosolar molecular cloud, generated via enhanced trapping of galactic cosmic rays. The higher and possibly variable apparent {sup 10}Be/{sup 9}Be ratios of canonical CAIs reflect additional spallogenesis, either in the gaseous CAI-forming reservoir, or in the inclusions themselves: this indicates at least two nucleosynthetic sources of {sup 10}Be in the early solar system. The most promising locale for {sup 10}Be synthesis is close to the proto-Sun during its early mass-accreting stages, as these are thought to coincide with periods of intense particle irradiation occurring on timescales significantly shorter than the formation interval of canonical CAIs.

  20. EVIDENCE FOR MULTIPLE SOURCES OF 10Be IN THE EARLY SOLAR SYSTEM

    Beryllium-10 is a short-lived radionuclide (t1/2 = 1.4 Myr) uniquely synthesized by spallation reactions and inferred to have been present when the solar system's oldest solids (calcium-aluminum-rich inclusions, CAIs) formed. Yet, the astrophysical site of 10Be nucleosynthesis is uncertain. We report Li-Be-B isotope measurements of CAIs from CV chondrites, including CAIs that formed with the canonical 26Al/27Al ratio of ∼5 × 10–5 (canonical CAIs) and CAIs with Fractionation and Unidentified Nuclear isotope effects (FUN-CAIs) characterized by 26Al/27Al ratios much lower than the canonical value. Our measurements demonstrate the presence of four distinct fossil 10Be/9Be isochrons, lower in the FUN-CAIs than in the canonical CAIs, and variable within these classes. Given that FUN-CAI precursors escaped evaporation-recondensation prior to evaporative melting, we suggest that the 10Be/9Be ratio recorded by FUN-CAIs represents a baseline level present in presolar material inherited from the protosolar molecular cloud, generated via enhanced trapping of galactic cosmic rays. The higher and possibly variable apparent 10Be/9Be ratios of canonical CAIs reflect additional spallogenesis, either in the gaseous CAI-forming reservoir, or in the inclusions themselves: this indicates at least two nucleosynthetic sources of 10Be in the early solar system. The most promising locale for 10Be synthesis is close to the proto-Sun during its early mass-accreting stages, as these are thought to coincide with periods of intense particle irradiation occurring on timescales significantly shorter than the formation interval of canonical CAIs.

  1. Concentration measurement of yeast suspensions using high frequency ultrasound backscattering.

    Elvira, Luis; Vera, Pedro; Cañadas, Francisco Jesús; Shukla, Shiva Kant; Montero, Francisco

    2016-01-01

    This work proposes the use of an ultrasound based technique to measure the concentration of yeasts in liquid suspension. This measurement was achieved by the detection and quantification of ultrasonic echoes backscattered by the cells. More specifically, the technique was applied to the detection and quantification of Saccharomyces cerevisiae. A theoretical approach was proposed to get the average density and sound speed of the yeasts, which were found to be 1116 kg/m(3) and 1679 m/s, respectively. These parameters were needed to model the waves backscattered by each single cell. A pulse-echo arrangement working around 50 MHz, being able to detect echoes from single yeasts was used to characterize experimentally yeast solutions from 10(2) to 10(7)cells/ml. The Non-negative Matrix Factorization denoising technique was applied for data analysis. This technique required a previous learning of the spectral patterns of the echoes reflected from yeasts in solution and the base noise from the liquid medium. Comparison between pulse correlation (without denoising) and theoretical and experimental pattern learning was made to select the best signal processing. A linear relation between ultrasound output and concentration was obtained with correlation coefficient R(2)=0.996 for the experimental learning. Concentrations from 10(4) to 10(7)cells/ml were detected above the base noise. These results show the viability of using the ultrasound backscattering technique to detect yeasts and measure their concentration in liquid cultures, improving the sensitivity obtained using spectrophotometric methods by one order of magnitude. PMID:26361271

  2. Ambient sesquiterpene concentration and its link to air ion measurements

    B. Bonn

    2006-12-01

    Full Text Available Ambient air ion size distributions have been measured continuously at the Finnish boreal forest site in Hyytiälä since spring 2003. In general, these measurements show a maximum of air ions below 1.0 nm in diameter. But this physical characterization does not provide any information about the ion's chemical composition, which is one key question regarding the explanation of nucleation events observed. In this study we propose a link of the observed maximum of negative air ions between 0.56 and 0.75 nm to the so-called stabilised Criegee biradical, formed in the reaction of biogenic sesquiterpenes with ozone and predominantly destroyed by its reaction with ambient water vapour. Calculations of the electron and proton affinities of 120 kJ mol−1 (1.24 eV and of 960 kJ mol−1 support this link. Other possible candidates such as sulphuric acid derived clusters are unable to explain the observations made. By using this approach, we are able to calculate the ambient concentration of sesquiterpenes at the air ion instrument inlet with a high time resolution on the daily and seasonal scale. The estimated concentration is found to reveal the same seasonal pattern as emission measurements conducted at shoot level. As expected for biogenic VOCs, the concentration is obtained highest during summer (maximum values of about 100 pptv and smallest during winter (minimum less than 1 pptv. Because of the sesquiterpenes high reactivity and its low ambient concentrations, this approach can be a first step in understanding their emission and their impact on atmospheric chemistry in more detail. The findings presented are highly relevant for emission budgets too, since boreal forests are extended over large areas of the globe.

  3. Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)

    Valette-Silver, J. N.; Brown, L.; Pavich, M.; Klein, J.; Middleton, R.

    1986-01-01

    10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses. In the cores, we observed two increases in 10Be concentration concomitant with two major changes in the pollen composition of the sediments. These two pollen changes each correspond to well-dated agricultural horizons reflecting different stages in the introduction of European farming techniques [2]. In the Chesapeake Bay area, the agricultural development, associated with forest clearing, appears to have triggered the erosion, transport, and sedimentation into the river mouths of large quantities of 10Be-rich soils. This phenomenon explains the observed rise in the sedimentation rate associated with increases in agricultural land-use. ?? 1986.

  4. Measuring uncertainty in modeling toxic concentrations in the Niagara River

    Franceschini, S.; Tsai, C.

    2004-12-01

    degree of accuracy in the estimation of the first few statistical moments of a model output distribution. Furthermore, the probabilistic analysis can be used as a more rigorous method to compare the modeled results with established water quality criteria. In this study, the toxic concentrations computed at the end of the Niagara River and their estimated variability will be compared with field data measurements. The purpose of this comparison is two-fold: (a) to evaluate the accuracy of the Modified Rosenblueth method in measuring the uncertainty of toxic concentration in the Niagara River and (b) to quantify the risk of exceeding established water quality standards when such uncertainty is accounted for.

  5. Headwall erosion rates from cosmogenic (10) Be in supraglacial debris, Chhota Shigri Glacier, Indian Himalaya

    Scherler, Dirk; Egholm, David

    2016-04-01

    Debris-covered glaciers are widespread within the Himalaya and other steep mountain ranges. They testify to active erosion of ice-free bedrock hillslopes that tower above valley glaciers, sometimes more than 1 km high. It is long known that debris cover significantly reduces surface ablation rates and thereby influences glacial mass balances; but its dynamic evolution along with climatic and topographic changes is poorly studied. Better understanding the coupling of ice-free bedrock hillslopes and glaciers in steep mountains requires means to assess headwall erosion rates. Here, we present headwall erosion rates derived from 10Be concentrations in the ablation-dominated medial moraine of the Chhota Shigri Glacier, Indian Himalaya. We combine our empirical, field-based approach with a numerical model of headwall erosion and glacial debris transport to assess permissible patterns of headwall erosion on the ice-free bedrock hillslopes surrounding the Chhota Shigri Glacier. Our five samples, each separated by approximately 500 m along the glacier, consist of an amalgamation of >1000 surface clasts with grain sizes between ˜1 and ˜30 mm that were taken from the medial moraine. Our results show that 10Be concentrations increase downglacier from ˜3×104 to ˜6×104 atoms g‑1, yielding headwall erosion rates of ˜1.3-0.6 mm yr‑1. The accumulation of 10Be during debris residence on the ice surface can only account for a small fraction (cracking, e.g., spatially uniform versus temperature dependent.

  6. How reliable are crystalline silica dust concentration measurements?

    Cox, L A; Van Orden, D R; Lee, R J; Arlauckas, S M; Kautz, R A; Warzel, A L; Bailey, K F; Ranpuria, A K

    2015-10-01

    To determine how reliably commercial laboratories measure crystalline silica concentrations corresponding to OSHA's proposed limits, 105 filters were prepared with known masses of 20, 40, and 80 μg of respirable quartz corresponding to airborne silica concentrations of 25, 50, and 100 μg/m(3) and were submitted, in a blind test, to qualified commercial laboratories over a nine month period. Under these test conditions, the reported results indicated a lack of accuracy and precision needed to reliably inform regulatory compliance decisions. This was true even for filters containing only silica, without an interfering matrix. For 36 filters loaded with 20 or more micrograms of silica, the laboratories reported non-detected levels of silica. Inter-laboratory variability in this performance test program was so high that the reported results could not be used to reliably discriminate among filters prepared to reflect 8-h exposures to respirable quartz concentrations of 25, 50 and 100 μg/m(3). Moreover, even in intra-laboratory performance, there was so much variability in the reported results that 2-fold variations in exposure concentrations could not be reliably distinguished. Part of the variability and underreporting may result from the sample preparation process. The results of this study suggest that current laboratory methods and practices cannot necessarily be depended on, with high confidence, to support proposed regulatory standards with reliable data. PMID:26160597

  7. Measurements of divertor impurity concentrations on DIII-D

    Carbon emissions in the DIII-D divertor during partial detachment have been measured, and the deduced radiated power and the temporal behavior of the impurity emissions from spectroscopy are in good agreement with bolometer measurements. Effective electron temperatures from line ratios for CIV (9-11 eV) and CIII (6-8 eV) are correlated with DTS measured electron temperatures to determine the spatial location of the carbon radiation zone. During PDD operation, the bulk of the divertor radiation is emitted from CIV near the X- point while deuterium radiation is strongest near the outer strikepoint. The carbon ion concentrations are in the range of 1% - 4% of the electron density

  8. Detecting low concentrations of plutonium hydride with magnetization measurements

    Kim, Jae Wook; Mun, E. D.; Baiardo, J. P.; Zapf, V. S.; Mielke, C. H. [National High Magnetic Field Laboratory, MPA-CMMS, Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545 (United States); Smith, A. I.; Richmond, S.; Mitchell, J.; Schwartz, D. [Nuclear Material Science Group, MST-16, LANL, Los Alamos, New Mexico 87545 (United States)

    2015-02-07

    We report the formation of plutonium hydride in 2 at. % Ga-stabilized δ-Pu, with 1 at. % H charging. We show that magnetization measurements are a sensitive, quantitative measure of ferromagnetic plutonium hydride against the nonmagnetic background of plutonium. It was previously shown that at low hydrogen concentrations, hydrogen forms super-abundant vacancy complexes with plutonium, resulting in a bulk lattice contraction. Here, we use magnetization, X-ray, and neutron diffraction measurements to show that in addition to forming vacancy complexes, at least 30% of the H atoms bond with Pu to precipitate PuH{sub x} on the surface of the sample with x ∼ 1.9. We observe magnetic hysteresis loops below 40 K with magnetic remanence, consistent with ferromagnetic PuH{sub 1.9}.

  9. Detecting low concentrations of plutonium hydride with magnetization measurements

    We report the formation of plutonium hydride in 2 at. % Ga-stabilized δ-Pu, with 1 at. % H charging. We show that magnetization measurements are a sensitive, quantitative measure of ferromagnetic plutonium hydride against the nonmagnetic background of plutonium. It was previously shown that at low hydrogen concentrations, hydrogen forms super-abundant vacancy complexes with plutonium, resulting in a bulk lattice contraction. Here, we use magnetization, X-ray, and neutron diffraction measurements to show that in addition to forming vacancy complexes, at least 30% of the H atoms bond with Pu to precipitate PuHx on the surface of the sample with x ∼ 1.9. We observe magnetic hysteresis loops below 40 K with magnetic remanence, consistent with ferromagnetic PuH1.9

  10. Experimental investigation of saturated polarization spectroscopy for quantatative concentration measurements

    Polarization-spectroscopy (PS) line shapes and signal intensities are measured in well-characterized hydrogen-air flames operated over a wide range of equivalence ratios. We use both low (perturbative) and high (saturating) pump beam intensities in the counterpropagating pump-probe geometry. The effects of saturation on the line-center signal intensity and the resonance linewidth are investigated. The PS signal intensities are used to measure relative OH number densities in a series of near-adiabatic flames at equivalence ratios (φ) ranging from 0.5 to 1.5. The use of saturating pump intensities minimizes the effect of pump beam absorption, providing more accurate number density measurements. When calibrated to the calculated OH concentration in the φ=0.6 flame, the saturated PS number density measurements probing the P1(2) transition are in excellent agreement with OH absorption measurements, equilibrium calculations of OH number density, and previous saturated degenerate four-wave mixing OH number density measurements. (c) 2000 Optical Society of America

  11. Plasma drug concentrations and physiological measures in 'dance party' participants.

    Irvine, Rodney J; Keane, Michael; Felgate, Peter; McCann, Una D; Callaghan, Paul D; White, Jason M

    2006-02-01

    The increasing use of (+/-) 3,4-methylenedioxymethamphetamine (MDMA) in the setting of large dance parties ('raves') and clubs has been the source of some concern, because of potential acute adverse events, and because animal studies suggest that MDMA has the potential to damage brain serotonin (5-HT) neurons. However, it is not yet known whether MDMA, as used in the setting of dance parties, leads to plasma levels of MDMA that are associated with toxicity to 5-HT neurons in animals. The present study sought to address this question. Plasma MDMA concentrations, vital signs, and a variety of blood and urine measures were obtained prior to, and hours after, individuals attended a dance party. After the dance party, subjects were without clinical complaints, had measurable amounts of residual MDMA in plasma, and nearly half of the subjects also tested positive for methamphetamine, another amphetamine analog that has been shown to have 5-HT neurotoxic potential in animals. Plasma concentrations of MDMA did not correlate with self-reported use of 'ecstasy' and, in some subjects, overlapped with those that have been associated with 5-HT neurotoxicity in non-human primates. Additional subjects were likely to have had similar concentrations while at the dance party, when one considers the reported time of drug ingestion and the plasma half-life of MDMA in humans. Hematological and biochemical analyses were generally unremarkable. Moderate increases in blood pressure, heart rate and body temperature were observed in the subjects with the highest MDMA plasma concentrations. These findings are consistent with epidemiological findings that most people who use MDMA at dance parties do not develop serious clinical complications, and suggest that some of these individuals may be at risk for developing MDMA-induced toxicity to brain serotonin neurons. PMID:16192986

  12. Dense gas boundary layer experiments: Visualization, pressure measurements, concentration evaluation

    Reichenbach, H.; Neuwald, P. [Ernst-Mach-Institut, Freiburg (DE); Kuhl, A.L. [R and D Associates, Los Angeles, CA (United States)

    1992-11-01

    This technical report describes methods that were applied to investigate turbulent boundary layers generated by inviscid, baroclinic effects. The Cranz-Schardin 24-sparks camera was used to visualize the interactions of a planar shock wave with a Freon R12-layer. The shock propagates more slowly in the Freon layer than in air because of its smaller sound speed. This causes the shock front to be curved and to be reflected between the wall and the layer interface. As a consequence of the reflection process, a series of compression and expansion waves radiate from the layer. Large fluctuations in the streamwise velocity and in pressure develop for about 1 ms. These waves strongly perturb the interface shear layer, which rapidly transitions to a turbulent boundary flow. Pressure measurements showed that the fluctuations in the Freon layer reach a peak pressure 4 times higher than in the turbulent boundary flow. To characterize the preshock Freon boundary layer, concentration measurements were performed with a differential interferometry technique. The refraction index of Freon R12 is so high that Mach-Zehnder interferometry was not successful in these experiments. The evaluation of the concentration profile is described here in detail. Method and results of corresponding LDV measurements under the same conditions are presented in a different report, EMI Report T 9/92. The authors plan to continue the dense gas layer investigations with the gas combination helium/Freon.

  13. Spectrally-resolved measurement of concentrated light distributions for Fresnel lens concentrators.

    Besson, P; White, P McVey; Dominguez, C; Voarino, P; Garcia-Linares, P; Lemiti, M; Schriemer, H; Hinzer, K; Baudrit, M

    2016-01-25

    A test method that measures spectrally resolved irradiance distribution for a concentrator photovoltaic (CPV) optical system is presented. In conjunction with electrical I-V curves, it is a means to visualize and characterize the effects of chromatic aberration and nonuniform flux profiles under controllable testing conditions. The indoor characterization test bench, METHOD (Measurement of Electrical, Thermal and Optical Devices), decouples the temperatures of the primary optical element (POE) and the cell allowing their respective effects on optical and electrical performance to be analysed. In varying the temperature of the POE, the effects on electrical efficiency, focal distance, spectral sensitivity, acceptance angle and multi-junction current matching profiles can be quantified. This work presents the calibration procedures to accurately image the spectral irradiance distribution of a CPV system and a study of system behavior over lens temperature. PMID:26832591

  14. Energy yield determination of concentrator solar cells using laboratory measurements

    Geisz, John F.; García, Iván; McMahon, William E.; Steiner, Myles A.; Ochoa, Mario; France, Ryan M.; Habte, Aron; Friedman, Daniel J.

    2015-09-01

    The annual energy conversion efficiency is calculated for a four junction inverted metamorphic solar cell that has been completely characterized in the laboratory at room temperature using measurements fit to a comprehensive optoelectronic model of the multijunction solar cells. A simple model of the temperature dependence is used predict the performance of the solar cell under varying temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are highlighted.

  15. Measurement of surface concentration of fluorophores using fluorescence fluctuation spectroscopy

    Delon, Antoine; Delapierre, Guillaume; Jaffiol, Rodolphe

    2006-01-01

    Fluorescence fluctuation spectroscopy is applied to study molecules, passing through a small observation volume, usually subjected to diffusive or convective motion in liquid phase. We suggest that such a technique could be used to measure the areal absolute concentration of fluorophores deposited on a substrate or imbedded in a thin film, with a resolution of a few micrometers. The principle is to translate the solid substrate in front of a confocal fluorescence microscope objective and to record the subsequent fluctuations of the fluorescence intensity. The validity of this concept is investigated on model substrates (fluorescent microspheres) and DNA biochips.

  16. Clustering in non-self-conjugate nuclei 10Be and 18O

    Clustering phenomena in 10Be and 18O were studied by means of resonance elastic scattering of α-particles on 6He and 14C. Excitation functions for α+6He and α+14C were measured and detailed R-matrix analyses of the excitation functions was performed. We compare the experimental results with the predictions of modern theoretical approaches and discuss properties of cluster rotational bands

  17. Measurements of indoor 222Rn concentration in two art galleries

    It is point out that radon and their decay products in environment give high dose to human lung. Studies indicate that the indoor radon inhalation by humans has been considered probably the second most important cause of lung cancer after of smoking. A passive-type radon detector was used for measuring indoor radon concentration in two art galleries at Rio de Janeiro city during 90 days January to March, 2009. The aim of this study is to evaluate the occupational and public radon exposure in art galleries and museums. This paper shows the preliminary results of samples collected at two art galleries located in Gavea, Rio de Janeiro city. 30 LEXAN (GE) track detectors were exposed in the air (indoor as well as outdoor). The samples were collected in the same building which is a construction of XIX century. The analysis of the results suggests that the 222Rn concentration levels are different in both sampling site, in closed environmental, demonstrating that, although the construction materials are the same the absence of circulating air is a factor very important to increase the concentration of indoor Rn. (author)

  18. Measurements of thoron and radon progeny concentrations in Beijing, China

    It has been reported that thoron levels in China are above the world average and may therefore make a significant contribution to the natural background radiation dose. We therefore conducted a pilot study of concentrations of both thoron and radon progeny during the spring of 2006 in the Beijing area, China. A new type of portable 24 h integrating monitor with a CR-39 detector was used during the survey. Seventy dwellings and eight outdoor sites were measured during the survey. For country houses built of red bricks and slurry, the average equilibrium equivalent concentrations (EEC) of thoron and radon were 1.02 ± 0.48 and 16.41 ± 9.02 Bq m-3, respectively, whereas for city dwellings built of cement blocks and floor slabs, the results were 0.48 ± 0.47 and 11.50 ± 6.99 Bq m-3 for thoron and radon, respectively. For outdoor air, concentrations of thoron and radon progeny were 0.29 ± 0.28 and 7.05 ± 2.68 Bq m-3, respectively. Radiation exposures from thoron and radon progeny were also evaluated; the ratio of dose contribution from thoron progeny to that of radon progeny was evaluated to be 28% and 17% in country houses and city dwellings, respectively. (note)

  19. [Inhaled nitric monoxide. Application and continuous measurement of concentration].

    Benzing, A; Beyer, U; Kiefer, P; Geiger, K

    1993-03-01

    Inhaled nitric oxide (NO) is a selective pulmonary vasodilator that may be useful in the treatment of patients with severe pulmonary hypertension. We describe a delivery system of inhaled NO that allows safe application and continuous measurement of the inspired NO concentration during mechanical ventilation. From a gas cylinder containing NO in N2 (600 ppm NO), an adjustable amount of gas is introduced into the inspiratory side of the tubing system via a pressure reduction valve, a magnetic valve, and a special injection nozzle. The NO concentration is diluted to the desired value by the tidal volume. The magnetic valve is connected to the ventilator and opens at the beginning of each inspiration and closes after a predetermined time. The gas volume is proportional to the pressure at the magnetic valve and the opening time. To monitor the inspiratory NO concentration, a specimen of gas is taken from an angle-connector and passed over an electrochemical sensor. The second nozzle of the sensor is connected to a water seal, which is adjusted to the positive end-expiratory pressure level of the ventilator to insure that the gas flow over the sensor is limited to inspiration. PMID:8480905

  20. Measurement of steroid concentrations in brain tissue: methodological considerations.

    Taves, Matthew D; Ma, Chunqi; Heimovics, Sarah A; Saldanha, Colin J; Soma, Kiran K

    2011-01-01

    It is well recognized that steroids are synthesized de novo in the brain (neurosteroids). In addition, steroids circulating in the blood enter the brain. Steroids play numerous roles in the brain, such as influencing neural development, adult neuroplasticity, behavior, neuroinflammation, and neurodegenerative diseases such as Alzheimer's disease. In order to understand the regulation and functions of steroids in the brain, it is important to directly measure steroid concentrations in brain tissue. In this brief review, we discuss methods for the detection and quantification of steroids in the brain. We concisely present the major advantages and disadvantages of different technical approaches at various experimental stages: euthanasia, tissue collection, steroid extraction, steroid separation, and steroid measurement. We discuss, among other topics, the potential effects of anesthesia and saline perfusion prior to tissue collection; microdissection via Palkovits punch; solid phase extraction; chromatographic separation of steroids; and immunoassays and mass spectrometry for steroid quantification, particularly the use of mass spectrometry for "steroid profiling." Finally, we discuss the interpretation of local steroid concentrations, such as comparing steroid levels in brain tissue with those in the circulation (plasma vs. whole blood samples; total vs. free steroid levels). We also present reference values for a variety of steroids in different brain regions of adult rats. This brief review highlights some of the major methodological considerations at multiple experimental stages and provides a broad framework for designing studies that examine local steroid levels in the brain as well as other steroidogenic tissues, such as thymus, breast, and prostate. PMID:22654806

  1. Measurement of steroid concentrations in brain tissue: methodological considerations

    MatthewDTaves

    2011-09-01

    Full Text Available It is well recognized that steroids are synthesized de novo in the brain (neurosteroids. In addition, steroids circulating in the blood enter the brain. Steroids play numerous roles in the brain, such as influencing neural development, behavior, neuroplasticity, and inflammation. In order to understand the regulation and functions of steroids in the brain, it is important to directly measure steroid concentrations in brain tissue. In this brief review, we discuss methods for the detection and quantification of steroids in the brain. We concisely present the major advantages and disadvantages of different technical approaches at various experimental stages: euthanasia, tissue collection, steroid extraction, steroid separation, and steroid measurement. We discuss, among other topics, the potential effects of anesthesia and saline perfusion prior to tissue collection; microdissection via Palkovits punch; solid phase extraction; chromatographic separation of steroids; and immunoassays and mass spectrometry for steroid quantification, particularly the use of mass spectrometry for “steroid profiling.” Finally, we discuss the interpretation of local steroid concentrations, such as comparing steroid levels in brain tissue with those in the circulation (plasma vs. whole blood samples; total vs. free steroid levels. This brief review highlights some of the major methodological considerations at multiple experimental stages and provides a broad framework for designing studies that examine local steroid levels in the brain as well as other tissues.

  2. Fluorescence lifetime measurements of boronate derivatives to determine glucose concentration

    Gable, J H

    2000-06-01

    A novel investigation into the fluorescence lifetimes of molecules, both established and newly designed, was performed. These molecules are the basis of a continuous, minimally invasive, glucose sensor based on fluorescence lifetime measurements. This sensor, if coupled with an automated insulin delivery device, would effectively create an artificial pancreas allowing for the constant monitoring and control of glucose levels in a person with diabetes. The proposed sensor includes a fluorescent molecule that changes its' fluorescence properties upon binding selectively and reversibly to glucose. One possible sensor molecule is N-methyl-N-(9-methylene anthryl)-2-methylenephenylboronic acid (AB). The fluorescence intensity of AB was shown to change in response to changing glucose concentrations. (James, 1994) James proposed that when glucose binds to AB the fluorescence intensity increases due to an enhancement of the N{yields}B dative bond which prevents photoinduced electron transfer (PET). PET from the amine (N) to the fluorophore (anthracene) quenches the fluorescence. The dative bond between the boron and the amine can prevent PET by involving the lone pair of electrons on the amine in interactions with the boron rather than allowing them to be transferred to the fluorophore. Results of this research show the average fluorescence lifetime of AB also changes with glucose concentration. It is proposed that fluorescence is due to two components: (1) AB with an enhanced N{yields}B interaction, and no PET, and (2) AB with a weak N{yields}B interaction, resulting in fluorescence quenching by PET. Lifetime measurements of AB as a function of both the pH of the solvent and glucose concentration in the solution were made to characterize this two component system and investigate the nature of the N{yields}B bond. Measurements of molecules similar to AB were also performed in order to isolate behavior of specific AB constituents. These molecules are 9

  3. Guarded capacitance probes for measuring particle concentration and flow

    Louge, Michel Y.

    1995-01-01

    Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall.

  4. Non-invasive measurement of chemotherapy drug concentrations in tissue: preliminary demonstrations of in vivo measurements

    Measurements of the tissue concentrations of two chemotherapy agents have been made in vivo on an animal tumour model. The method used is based on elastic-scattering spectroscopy (ESS) and utilizes a fibre-optic probe spectroscopic system. A broadband light source is used to acquire data over a broad range of wavelengths and, therefore, to facilitate the separation of absorptions from various chromophores. The results of the work include measurements of the time course of the drug concentrations as well as a comparison of the optical measurements with high-performance liquid chromatography (HPLC) analysis of the drug concentrations at the time of sacrifice. It is found that the optical measurements correlate linearly with HPLC measurements, but give lower absolute values. (author)

  5. Cosmogenic 10Be: A critical view on its widespread dominion in geosciences

    D Lal

    2000-03-01

    The radionuclide 10Be (half-life 9 1:5 my), produced naturally in the Earth's atmosphere by nuclear interactions of cosmic rays, was sought in ocean sediments in the late fifties, considering its potential usefulness as a radiotracer for dating sediments. 10Be was discovered independently by two groups, one in India and the other in the USA, and used only for dating marine sediments and manganese nodules until the seventies. Subsequently, as a result of a technical advance resulting in the improvement in the sensitivity of measurement of 10Be by about a factor of 106, there was a global rush to measure this nuclide in most materials participating in the physical, chemical and biological processes in the dynamic geosphere. This paper outlines the reasons for this ``isotope rush'', and the lessons learned from these studies. I also present my personal views of the special attractive features of this nuclide on the one hand, and on the other, the pitfalls or the wrong message this nuclide could convey!

  6. Nuclear traces on solids and concentration measurements of intramural radon

    The Department of Energy, the Environmental Protection Agency of United States and the European Community, have dedicated very important resources to study and analysis of intramural radon, its effects in public health and on remediation and control actions, trying to obtain lower levels. In Mexico have been organized intramural radon research programs by several institutions. With the proposal to contribute to intramural radon knowledge and its concentration levels in our country, the Dosimetry Applications Project of Physics Institute of the National Autonomous University of Mexico, in collaboration with the Physics Department of Research and Advanced Studies Center, have developed the methodology for intramural radon measurement by nuclear traces on solids. In this work a passive detector is presented for radiation measurement, using polycarbonate (C R-39) as sensitive material to particles alpha, as well as the protocols for the chemical engraving, the automatic reading system and calibration procedures. The results obtained are presented with this method in houses, buildings and work places. These results were compared with other, obtained with dynamic systems and other methodologies used by another research groups. These comparisons have achieve to take a high reliability in our measurements. (Author)

  7. Principles of measuring free thyroid hormone concentrations in serum

    In the first part of this article, an overview of the present status of the 'free hormone concept' has been presented, and the conclusion drawn that - at the present time - the notion that free hormone concentrations in blood govern a hormone's physiological effects may represent an oversimplification. In the second, a brief review of the fundamental principles of some traditional methods of free hormone measurement has been offered, along with those of the newer radioimmunoassays. It is shown that, in particular, the labelled analogue assays do not operate in accordance with the principles claimed by the manufacturers, and cannot in their present form be regarded or described as genuine free hormone assay methods. The assertion underlies the many diagnostic problems and anomalies that have attented their use. (orig.)

  8. An Alpha spectrometer for measuring radon daughter individual activity concentration

    In the frame of the program of the Institute for Radiation Protection of ENEA, related to the evaluation of dose from radon and thoron progeny, an alpha spectrometer for the continuous air monitoring (CAM type) of radon and thoron has been realized. The constructive characteristics of the device are here presented together with energy and efficiency calibration. The device allows, by means of a screen type diffusion battery and a filter, to determinate the single radioactivity of each radionuclide of the progeny selecting them in relation to their diffusive behaviour (dichotomous particle size selection). The three-count filter method has been employed to measure the concentrations of 218Po, 214Pb and 214Bi in air. Radon and thoron effective doses using a dosimetric, instead of an epidemiologic approach, will be then evaluated

  9. Measurement of PCB concentrations in waters using a biomonitoring programme

    The book describes a PCB biomonitoring programme which was developed for measuring instantaneous PCB concentrations and permits the compilation of PCB action cadastres for different types of waters and subsequent derivation of current trends. Six representative congeners were selected as a basis for the quantitative routine analysis. The fish species bream (abramis brama) and roach (rutilus rutilus) were used as indicators in the PCB biomonitoring programme on account of their distribution and ecological demands. The age and growth rate of each fish destined for analysis was determined so as to ensure that only healthy fish would be used. In both fish species the dorsal musulature with its low scatter of test results and consistent PCB pattern (internal quantification) proved a representative body region. (orig.)

  10. Measurement of interstitial cetirizine concentrations in human skin

    Petersen, Lars Jelstrup; Church, M K; Rihoux, J P;

    1999-01-01

    BACKGROUND: The purpose of the present study was to measure the concentrations of cetirizine in the extracellular water compartment in intact human skin and assess simultaneously inhibition of histamine-induced wheal and flare reactions. METHODS: Skin cetirizine levels were collected by the...... microdialysis technique and analyzed by high-pressure liquid chromatography with mass spectrometry detection. Skin levels in 20 subjects were compared to plasma levels for 4 h after a single oral dose of 10 or 20 mg of cetirizine. Skin prick tests were performed with histamine 100 mg/ml. RESULTS: Plasma...... cetirizine levels increased within 30 min to reach peak values of 315+/-10 and 786+/-45 ng/ml 90-120 min after administration of 10 and 20 mg of cetirizine. This was followed by a slow decline. In the skin, dialysate cetirizine levels (non-protein-bound fraction only) peaked at 1.6+/-0.1 and 2.4+/-0.3 ng...

  11. Measurement of radon concentration in groundwater of Kumaon Himalaya

    In this study, radon concentration in springs and hand pumps of Kumaon Himalaya, India was measured using radon emanometry technique. The radon measurements were made in springs and groundwater from the hand pumps being used as drinking water sources by general population. The hand pumps and springs were selected near the dwellings and workplaces, where the general public utilizes these water sources for their daily needs. The water samples from springs were collected in an air-tight bottle from the original discharge point (outlet) of the spring having distinct geological unit and geohydrological regime. The water was transferred from discharge point of the spring to the bottom of the bottle using PVC tubing. For hand pumps, the water was pumped out for some time and the samples were collected in 1 L bottle directly from the pump outlet. After allowing the sample bottle to over flow for a while and when no bubbles were visually observed, the sample volume was reduced to a pre-marked position leaving 250 ml of air in the bottle above the water surface. The sample bottle was then connected in a close circuit with Lucas cell, hand operated rubber pump and a glass tube containing CaCl2 to absorb the moisture. The air was then circulated in close circuit for a period of 15 mm till the radon formed a uniform mixture with the air and the resulting alpha activity was recorded. The resulting numbers of the alpha counts were then converted into Bq/l by using the calibration factor 1 cpm = 0.0663 Bq/l. The results of radon measurements in springs and hand pumps from the study area are given. Field measurements were taken in different geological units of Kumaun region in Himalaya. The radon concentration in spring water varies from 1 Bq/l to 76 Bq/l with geometric mean 10 Bq/l, whereas in hand pumps it varies from 3 Bq/l to 392 Bq/l with geometric mean of 40 Bq/l. The higher values of radon in the water samples of hand pumps are possibly because of its greater depth, which

  12. Incision of the Danube River (Hungary), inferred by cosmogenic in situ 10Be and luminescence dating of terrace sediments

    Ruszkiczay-Rüdiger, Zsófia; Novothny, Ágnes; Braucher, Régis; Csillag, Gábor; Fodor, László; Molnár, Gábor; Thamó-Bozsó, Edit

    2014-05-01

    by field observation of the original bedding of the alluvial material. This is confirmed by the exponential decrease of 10Be concentration with depth along all depth profiles. The incision rate of the Danube river inferred by the preliminary cosmogenic nuclide terrace ages resulted to be 0.3 mm/a, while luminescence ages provided a rate of 0.1 mm/a. Our research was supported by the OTKA PD100315, PD83610, K62478, K68219 and 106197, by the EGT/Norwegian Financing Mechanism and MZFK, Hungary; the Research Scholarship of the French Embassy of Hungary; the French-Hungarian Balaton-Tét Program (FR-32/2007 and TÉT_11-2-2012-0005). The 10Be measurements were performed at the ASTER AMS national facility (CEREGE, Aix en Provence, France).

  13. Simulating the mobility of meteoric 10Be in the landscape through a coupled soil-hillslope model (Be2D)

    Campforts, Benjamin; Vanacker, Veerle; Vanderborght, Jan; Baken, Stijn; Smolders, Erik; Govers, Gerard

    2016-04-01

    Meteoric 10Be allows for the quantification of vertical and lateral soil fluxes over long time scales (103-105 yr). However, the mobility of meteoric 10Be in the soil system makes a translation of meteoric 10Be inventories into erosion and deposition rates complex. Here, we present a spatially explicit 2D model simulating the behaviour of meteoric 10Be on a hillslope. The model consists of two parts. The first component deals with advective and diffusive mobility of meteoric 10Be within the soil profile, and the second component describes lateral soil and meteoric 10Be fluxes over the hillslope. Soil depth is calculated dynamically, accounting for soil production through weathering as well as downslope fluxes of soil due to creep, water and tillage erosion. Synthetic model simulations show that meteoric 10Be inventories can be related to erosion and deposition across a wide range of geomorphological and pedological settings. Our results also show that meteoric 10Be can be used as a tracer to detect human impact on soil fluxes for soils with a high affinity for meteoric 10Be. However, the quantification of vertical mobility is essential for a correct interpretation of the observed variations in meteoric 10Be profiles and inventories. Application of the Be2D model to natural conditions using data sets from the Southern Piedmont (Bacon et al., 2012) and Appalachian Mountains (Jungers et al., 2009; West et al., 2013) allows to reliably constrain parameter values. Good agreement between simulated and observed meteoric 10Be concentrations and inventories is obtained with realistic parameter values. Furthermore, our results provide detailed insights into the processes redistributing meteoric 10Be at the soil-hillslope scale.

  14. Marine biogeochemistries of Be and Al: A study based on cosmogenic 10Be, Be and Al in marine calcite, aragonite, and opal

    Weiquan Dong; Devendra Lal; Barbara Ransom; Wolfgang Berger; Marc W Caffee

    2001-06-01

    The geochemical behaviors of Be and Al in ocean waters have been successfully studied in recent years using natural, cosmogenic, radioactive 10Be and 26Al as tracers. The present day dissolved concentrations and distribution of the stable and radioactive isotopes of Be and Al in ocean waters have revealed their short residence times and appreciable effects of exchange uxes at the coastal and ocean-sediment interfaces. It follows that concentrations of these particle-active elements must have varied in the past with temporal changes in climate, biological productivity and aeolian ux of continental detritus to the oceans. We therefore investigated the feasibility of extending the measurements of Be and Al isotope concentrations in marine systems to the 103-106 BP time scale. We report here the discovery of significant amounts of intrinsic Be and Al in marine foraminiferal calcite and coral aragonite, and of Al in opal (radiolarians) and aragonite (coral), which makes it possible to determine 10Be/Be and 26Al/Al in oceans in the past. We also report measured 10Be/9Be in foraminiferal calcite in Pacific Ocean cores, which reveal that the concentrations and ratios of the stable and cosmogenic isotopes of Be and Al have varied significantly in the past 30 ky. The implications of these results are discussed.

  15. Measurement Limits to $^{134}$Cs Concentration in Soil

    Ahn, J K; Lee, H M; Kim, T H; Park, J N; Kang, Y S; Lee, H S; Kim, S J; Park, J Y; Ryu, S Y; Kim, H Ch; Kang, W G; Kim, S K

    2009-01-01

    We investigate the caesium concentrations in soils in mountain areas near Gori nuclear power plant in Korea, focusing on the measurement limits to the $^{134}\\mathrm{Cs}$. In order to lower the minimum detectable amount (MDA) of activity for the $134}\\mathrm{Cs}$, we have used the ammonium molybdophosphase (AMP) precipitation method to get rid of the $^{40}$K existing in natural radioactivity, which reduces the MDA of activity about ten times smaller than those without the AMP precipitation method. The MDA results for the $^{134}\\mathrm{Cs}$ were found to be in the range between 0.015 and 0.044 Bq/kg-dry weight. In order to diminish the background, we also have measured a part of the soil samples in Yangyang, a small town in the east coast of Korea. However, it turns out that in order to detect the $^{134}\\mathrm{Cs}$ in the samples the MDA should be reduced to the level of mBq/kg-dry weight.

  16. Understanding complex exposure history of Mount Hampton, West Antarctica using cosmogenic 3He, 21Ne and 10Be in olivine

    Carracedo, Ana; Rodes, Angel; Stuart, Finlay; Smellie, John

    2016-04-01

    Combining stable and radioactive cosmogenic nuclides is an established tool for revealing the complexities of long-term landscape development. To date most studies have concentrated on 21Ne and 10Be in quartz. We have combined different chemical protocols for extraction of cosmogenic 10Be from olivine, and measured concentrations in olivine from lherzolite xenoliths from the peak of Mount Hampton (~3,200 m), an 11 Ma shield volcano on the West Antarctic rift flank. We combine this data with cosmogenic 3He (and 21Ne) in the olivines in order to unravel the long-term environmental history of the region. The mean 3He/21Ne ratio (1.98 ± 0.22) is consistent with the theoretical value and previous determinations. 10Be/3He ratios (0.012 to 0.018) are significantly lower than the instantaneous production ratio (~0.045). The data are consistent with 1-3 Ma of burial. The altitude of the volcano rules out over-topping of the peak by the West Antarctic Ice Sheet only possible burial could be generated by the growth of an ice cap although this contradicts the absence of evidence for ice cover. The 3He-10Be data can also be generated during episodic erosion of the volcanic ash over the last few million years. The data requires a minimum depth of 1 to 2.5 m for the samples during a minimum age of 5 Ma and maximum long-term erosion rate of ~0.5 m/Ma with at least one erosive episode reflecting short-term erosion rate of ~7 m/Ma that would have brought the samples into the surface during the last ~350 ka. Erosion in this type of landscape could be related to interglacial periods where cryostatic erosion can occur generating an increase in the erosion rate. This study shows that episodic erosion can produce stable-radioactive cosmogenic isotope systematics that are similar to those generated by exposure-burial cycles.

  17. Different techniques for measuring radon concentration in a spa environment

    In the context of radiation protection for both workers and the population in general, natural sources of radiation, and in particular radon gas and its short-life decay products assume great importance. In particular, workers in thermal spas can easily be exposed to a level of radon radiation and its decay products comparable to those in uranium mines, though often these workers are unaware of the danger. The main source of radon in thermal baths is the thermal water itself, coming as it often does from deep springs, and this can produce high radon concentrations which are left in those areas in which therapy is carried out. Another factor which cannot be overlooked is the radioactive content of thermal mud, often matured for long periods by contact with thermal water. Thermal cures, though varying slightly from site to site, consist principally of mud cures, hydro-therapy and inhalation in various forms. Both health workers and patients are exposed to radiation, most importantly certainly through inhalation, though in certain procedures ingestion and irradiation are also important factors. International organizations have been addressing the problem of radiation exposure to health workers in spas for a number of years and recently protective legislation has been introduced regarding the use of natural springs. In 1996, Directive 96/29/EURATOM, was issued which reflects the norms advocated in ICRP publications, notably publication no.65. This directive was subsequently embodied in Italian legislation (DL 241/00), providing for precise quantification of exposure levels for health spa workers. The object of the project undertaken by our group was thus the evaluation of the radiation doses for health workers and their patients in an Italian thermal health centre. A necessary step towards this was the exact measurement of radon concentrations in places where workers and patients are to be found

  18. Sup(10)Be variation in surficial sediments of the Central Indian Basin

    Nath, B.N.; Aldahan, A.; Possnert, G.; Selvaraj, K.; Mascarenhas-Pereira, M.B.L.; Chen, C.T.A.

    stream_size 23258 stream_content_type text/plain stream_name Nuclear_Instrum_Methods_Phys_Res_B_259_610.pdf.txt stream_source_info Nuclear_Instrum_Methods_Phys_Res_B_259_610.pdf.txt Content-Encoding UTF-8 Content-Type text....: +46 18 4713095; fax: +46 18 4712737. E-mail addresses: nagender@nio.org (B. Nagender Nath), ala. aldahan@geo.uu.se (A. Aldahan). Nuclear Instruments and Methods in Physics 1. Introduction The first measurements of 10 Be were made on deep-sea marine...

  19. Depth profiles of 10Be and 26Al in drill cores from northern Bavaria

    'In situ' produced, cosmogenic 10Be and 26Al have been measured in samples from a drill core from the surface to below 100 m. The data yield a local, average erosion rate of about 5 m/My. Below about 1 m of rock, the production of cosmogenic isotopes is dominated by processes induced by the secondary cosmic ray muon component. The results of simulation experiments -samples irradiated with negative muons at PSI - are in good agreement with the data from the depth profiles. (author) 2 figs., 2 refs

  20. A non-intrusive measurement technique applying CARS for concentration measurement in a gas mixing flow

    Yamamoto, Ken; Moriya, Madoka; Kuriyama, Reiko; Sato, Yohei

    2015-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscope system was built and applied to a non-intrusive gas concentration measurement of a mixing flow in a millimeter-scale channel. Carbon dioxide and nitrogen were chosen as test fluids and CARS signals from the fluids were generated by adjusting the wavelengths of the Pump and the Stokes beams. The generated CARS signals, whose wavelengths are different from those of the Pump and the Stokes beams, were captured by an EM-CCD camera after filtering out the excitation beams. A calibration experiment was performed in order to confirm the applicability of the built-up CARS system by measuring the intensity of the CARS signal from known concentrations of the samples. After confirming that the measured CARS intensity was proportional to the second power of the concentrations as was theoretically predicted, the CARS intensities in the gas mixing flow channel were measured. Ten different measurement points were set and concentrations of both carbon dioxide and nitrog...

  1. 10Be Content in Suevite Breccia from the Bosumtwi Impact Crater

    Losiak, Anna; Wild, Eva Maria; Michlmayr, Leonard; Koeberl, Christian

    2013-04-01

    separated from the sample solution. 10Be/9Be ratios were measured at the Vienna Environmental Research Accelerator Facility (VERA) at the University of Vienna. Results: Most samples have 10Be/9Be ratios indistinguishable from the blank value within 2? uncertainty. Samples located just below the boundary between impactites and lake deposits have slightly elevated (1 ? significant) 10Be/9Be ratios. Discussion: The data suggest that none of the analyzed samples present in the suevitic breccia of the Bosumtwi crater come from the surficial layer (0-20 m) of the target. A very small amount of the 10Be present in the layer directly underneath the lake sediments suggests that those two deposits were very efficiently separated from each other. Possibly, this separation was caused by the uppermost impact fallback layer described by Koeberl et al. (2007). Acknowledgment: Supported by University of Vienna doctoral school IK-1045 (Planetology). References: [1] Melosh H.J. 1988. Impact Cratering, Oxford University Press, 256 pp.. [2] Serefiddin F. et al. 2007. Geochimica et Cosmochimica Acta 71: 1574-1582. [3] Son T.H. and Koeberl C. 2007. GFF 29: 161-176. [4] Artemieva N.A. 2000. In: Impacts in Precambrian Shields, Springer, pp. 257-276. [5] Puura V. et al. 2004. Meteoritics & Planetary Science 39: 425-451. [6] Reimold W.U., et al. 1992. Geology 20:1079-1082. [7] Koeberl C. et al. 2007. Meteoritics & Planetary Science 42: 483-511. [8] Koeberl C. et al. 2007. Meteoritics & Planetary Science 42: 709-729.

  2. Variability of 10Be and δ18O in snow pits from Greenland and a surface traverse from Antarctica

    To examine temporal variability of 10Be in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of 10Be in glacial ice was explored through collection of the upper ∼5 cm of surface snow in Antarctica during part of the Swedish–Japanese traverse from Svea to Syowa station during the austral summer in 2007–2008. The results of the Greenlandic 10Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the δ18O data. The 10Be concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes. The Antarctic traverse data expose a negative correlation between 10Be and δ18O, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect 10Be concentrations in snow in Queen Maud Land, Antarctica.

  3. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    Andersen, Simon Ivar; Christensen, S. D.

    2000-01-01

    solvent mixture) is titrated with a solution of asphaltene in the same solvent. The asphaltene concentration of the injected solution is at a level above the critical micelle concentration (CMC). In the present paper the procedure is applied in investigation of asphaltenes as well as subfractions...

  4. Reactions with a 10Be beam to study the one-neutron halo nucleus 11Be

    Jones, K. L.

    2016-07-01

    Halo nuclei are excellent examples of few-body systems consisting of a core and weakly-bound halo nucleons. Where there is only one nucleon in the halo, as in 11Be, the many-body problem can be reduced to a two-body problem. The contribution of the 1s1/2 orbital to the ground state configuration in 11Be, characterized by the spectroscopic factor, S, has been extracted from direct reaction data by many groups over the past five decades with discrepant results. An experiment was performed at the Holifield Radioactive Ion Beam Facility using a 10Be primary beam at four different energies with the goal of resolving the discrepancy through a consistent analysis of elastic, inelastic, and transfer channels. Faddeev-type calculations, released after the publication of the experimental results, show that dynamic core excitation in the transfer process can lead to reduced differential cross sections at higher beam energies. This reduction would lead to the extraction of decreasing values of S with increasing beam energy. A 10Be(d,p) measurement at Ed greater than 25 MeV is necessary to investigate the effects of core excitation in the reaction.

  5. 10Be in late deglacial climate simulated by ECHAM5-HAM – Part 2: Isolating the solar signal from 10Be deposition

    A. M. Smith

    2013-10-01

    Full Text Available This study investigates the effect of deglacial climate on the deposition of the solar proxy 10Be globally, and at two specific locations, the GRIP site at Summit, Central Greenland, and the Law Dome site in coastal Antarctica. The deglacial climate is represented by three 30 yr time slice simulations of 10 000 BP (years before present = 1950 CE, 11 000 BP and 12 000 BP, compared with a preindustrial control simulation. The model used is the ECHAM5-HAM atmospheric aerosol–climate model, driven with sea surface temperatures and sea ice cover simulated using the CSIRO Mk3L coupled climate system model. The focus is on isolating the 10Be production signal, driven by solar variability, from the weather or climate driven noise in the 10Be deposition flux during different stages of climate. The production signal varies on lower frequencies, dominated by the 11yr solar cycle within the 30 yr time scale of these experiments. The climatic noise is of higher frequencies. We first apply empirical orthogonal functions (EOF analysis to global 10Be deposition on the annual scale and find that the first principal component, consisting of the spatial pattern of mean 10Be deposition and the temporally varying solar signal, explains 64% of the variability. The following principal components are closely related to those of precipitation. Then, we apply ensemble empirical decomposition (EEMD analysis on the time series of 10Be deposition at GRIP and at Law Dome, which is an effective method for adaptively decomposing the time series into different frequency components. The low frequency components and the long term trend represent production and have reduced noise compared to the entire frequency spectrum of the deposition. The high frequency components represent climate driven noise related to the seasonal cycle of e.g. precipitation and are closely connected to high frequencies of precipitation. These results firstly show that the 10Be atmospheric production

  6. Preliminary study of 10Be/7Be in rainwater from Xi'an by Accelerator Mass Spectrometry

    Zhang, Li

    2016-01-01

    The 10Be/7Be ratio is a sensitive tracer for the study of atmospheric transport, particularly with regard to stratosphere-troposphere exchange. Measurements with high accuracy and efficiency are crucial to 7Be and 10Be tracer studies. This article describes sample preparation procedures and analytical benchmarks for 7Be and 10Be measurements at the Xian Accelerator Mass Spectrometry (Xian-AMS) laboratory for the study of rainwater samples. We describe a sample preparation procedure to fabricate beryllium oxide (BeO) AMS targets that includes co-precipitation, anion exchange column separation and purification. We then provide details for the AMS measurement of 7Be and 10Be following the sequence BeO- -> Be2+ -> Be4+ in the Xian- AMS. The 10Be/7Be ratio of rainwater collected in Xian is shown to be about 1.3 at the time of rainfall. The virtue of the method described here is that both 7Be and 10Be are measured in the same sample, and is suitable for routine analysis of large numbers of rainwater samples by AMS.

  7. Weathering histories of Chinese loess deposits based on uranium and thorium series nuclides and cosmogenic 10Be

    The long, continuous deposition of dust in the Chinese loess plateau offers an unique opportunity to study the nature of soil weathering in a wide range of climatic conditions. In this paper we report on measurements of concentrations of U- and Th-series nuclides and of major cations in 150 loess and paleosol samples from five sites, going back 2.5 Ma. Using the results for 10Be concentrations in these soils, we determined the absolute amounts of water added to several soil units and obtained: (1) first-order leaching constants for U and several cations and (2) the compositions of the soils contributing to the dust-source regions and of the dust at deposition. Further, based on analyses of 230Th in soils deposited in the past ca. 140 ka, we determined when the soils weathered in the source regions. We conclude that most of the weathering in the dust-source regions may have occurred during the interglacials. 34 refs., 8 figs., 2 tabs

  8. A chronopotentiometric approach for measuring chloride ion concentration

    Abbas, Yawar; Olthuis, Wouter; Berg, van den Albert

    2013-01-01

    In this paper, a novel approach is reported for the electrochemical measurement of chloride ions in aqueous solution. This sensor is based on the stimulus/response principle of chronopotentiometry. A current pulse is applied at the Ag/AgCl working electrode and the potential change is measured with

  9. Direct measurement of uranium 235 concentration in uranium hexafluoride containers

    A simple, portable and autonomous apparatus is described. Isotopic ratio of uranium 235 can be determined in UF6 containers (type 30B or 48Y) without contact with the fissile material. A thermal neutron source induces, through the container wall, nuclear fissions. Fast neutrons produced by the nuclear reaction are detected and counted giving the concentration in uranium 235. Results obtained are presented and discussed

  10. A test of the cosmogenic 10Be(meteoric)/9Be proxy for simultaneously determining basin-wide erosion rates, denudation rates, and the degree of weathering in the Amazon basin

    Wittmann, H.; Blanckenburg, F.; Dannhaus, N.; Bouchez, J.; Gaillardet, J.; Guyot, J. L.; Maurice, L.; Roig, H.; Filizola, N.; Christl, M.

    2015-12-01

    We present an extensive investigation of a new erosion and weathering proxy derived from the 10Be(meteoric)/9Be(stable) ratio in the Amazon River basin. This new proxy combines a radioactive atmospheric flux tracer, meteoric cosmogenic 10Be, with 9Be, a trace metal released by weathering. Results show that meteoric 10Be concentrations ([10Be]) and 10Be/9Be ratios increase by >30% from the Andes to the lowlands. We can calculate floodplain transfer times of 2-30 kyr from this increase. Intriguingly however, the riverine exported flux of meteoric 10Be shows a deficit with respect to the atmospheric depositional 10Be flux. Most likely, the actual area from which the 10Be flux is being delivered into the mainstream is smaller than the basin-wide one. Despite this imbalance, denudation rates calculated from 10Be/9Be ratios from bed load, suspended sediment, and water samples from Amazon Rivers agree within a factor of 2 with published in situ 10Be denudation rates. Erosion rates calculated from meteoric [10Be], measured from depth-integrated suspended sediment samples, agree with denudation rates, suggesting that grain size-induced variations in [10Be] are minimized when using such sampling material instead of bed load. In addition, the agreement between erosion and denudation rates implies minor chemical weathering intensity in most Amazon tributaries. Indeed, the Be-specific weathering intensity, calculated from mobilized 9Be comprising reactive and dissolved fractions that are released during weathering, is constant at approximately 40% of the total denudation from the Andes across the lowlands to the Amazon mouth. Therefore, weathering in the Amazon floodplain is not detected.

  11. Confidence intervals for concentration and brightness from fluorescence fluctuation measurements.

    Pryse, Kenneth M; Rong, Xi; Whisler, Jordan A; McConnaughey, William B; Jiang, Yan-Fei; Melnykov, Artem V; Elson, Elliot L; Genin, Guy M

    2012-09-01

    The theory of photon count histogram (PCH) analysis describes the distribution of fluorescence fluctuation amplitudes due to populations of fluorophores diffusing through a focused laser beam and provides a rigorous framework through which the brightnesses and concentrations of the fluorophores can be determined. In practice, however, the brightnesses and concentrations of only a few components can be identified. Brightnesses and concentrations are determined by a nonlinear least-squares fit of a theoretical model to the experimental PCH derived from a record of fluorescence intensity fluctuations. The χ(2) hypersurface in the neighborhood of the optimum parameter set can have varying degrees of curvature, due to the intrinsic curvature of the model, the specific parameter values of the system under study, and the relative noise in the data. Because of this varying curvature, parameters estimated from the least-squares analysis have varying degrees of uncertainty associated with them. There are several methods for assigning confidence intervals to the parameters, but these methods have different efficacies for PCH data. Here, we evaluate several approaches to confidence interval estimation for PCH data, including asymptotic standard error, likelihood joint-confidence region, likelihood confidence intervals, skew-corrected and accelerated bootstrap (BCa), and Monte Carlo residual resampling methods. We study these with a model two-dimensional membrane system for simplicity, but the principles are applicable as well to fluorophores diffusing in three-dimensional solution. Using simulated fluorescence fluctuation data, we find the BCa method to be particularly well-suited for estimating confidence intervals in PCH analysis, and several other methods to be less so. Using the BCa method and additional simulated fluctuation data, we find that confidence intervals can be reduced dramatically for a specific non-Gaussian beam profile. PMID:23009839

  12. Measurement of Liver Iron Concentration by MRI Is Reproducible

    José María Alústiza

    2015-01-01

    Full Text Available Purpose. The objectives were (i construction of a phantom to reproduce the behavior of iron overload in the liver by MRI and (ii assessment of the variability of a previously validated method to quantify liver iron concentration between different MRI devices using the phantom and patients. Materials and Methods. A phantom reproducing the liver/muscle ratios of two patients with intermediate and high iron overload. Nine patients with different levels of iron overload were studied in 4 multivendor devices and 8 of them were studied twice in the machine where the model was developed. The phantom was analysed in the same equipment and 14 times in the reference machine. Results. FeCl3 solutions containing 0.3, 0.5, 0.6, and 1.2 mg Fe/mL were chosen to generate the phantom. The average of the intramachine variability for patients was 10% and for the intermachines 8%. For the phantom the intramachine coefficient of variation was always below 0.1 and the average of intermachine variability was 10% for moderate and 5% for high iron overload. Conclusion. The phantom reproduces the behavior of patients with moderate or high iron overload. The proposed method of calculating liver iron concentration is reproducible in several different 1.5 T systems.

  13. Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers

    Basinas, Ioannis; Sigsgaard, Torben; Bønløkke, Jakob Hjort;

    2016-01-01

    objective measurements has been limited. OBJECTIVE: To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm. METHODS: The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two...... quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers...

  14. Ultrasonic method for measurement of D2O concentration

    A correlation of the velocity of sound with mole percent of heavy water in D2O-H2O mixtures has been measured using a modified commercially available instrument. This is being developed as a practical method for the analysis of heavy water stored in 210 l drums. The drums need not be opened, and measurements can be made under field conditions. The application of this method would permit quick, in-field verification of drum contents in production or user facilities without having to violate drum seals

  15. Determination of {sup 10}Be, {sup 26}Al, and {sup 36}Cl in meteorites

    Merchel, S.; Herpers [Koeln Univ. (Germany); Neumann, S.; Michel, R. [Hannover Univ. (Germany); Kubik, P.W.; Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Long-lived cosmogenic radionuclides were determined in stony ({sup 10}Be, {sup 26}Al) and iron ({sup 10}Be, {sup 26}Al, {sup 36}Cl) meteorites using AMS after radiochemical separation. A selection of these data is briefly discussed with respect to exposure histories of the meteorites and is compared to model calculations. (author) 2 figs., 5 refs.

  16. Calculating Capstone Depleted Uranium Aerosol Concentrations from Beta Activity Measurements

    Beta activity measurements were used as surrogate measurements of uranium mass in aerosol samples collected during the field testing phase of the Capstone Depleted Uranium (DU) Aerosol Study. These aerosol samples generated by the perforation of armored combat vehicles were used to characterize the depleted uranium (DU) source term for the subsequent human health risk assessment (HHRA) of Capstone aerosols. Establishing a calibration curve between beta activity measurements and uranium mass measurements is straightforward if the uranium isotopes are in equilibrium with their immediate short-lived, beta-emitting progeny. For DU samples collected during the Capstone study, it was determined that the equilibrium between the uranium isotopes and their immediate short lived, beta-emitting progeny had been disrupted when penetrators had perforated target vehicles. Adjustments were made to account for the disrupted equilibrium and for wall losses in the aerosol samplers. Correction factors for the disrupted equilibrium ranged from 0.16 to 1, and the wall loss correction factors ranged from 1 to 1.92

  17. Quality control of the concentration measurement of specific radioactive isotopes

    The counting efficiency of a gamma spectroscopy chain with a Ge (H.p) detector was measured. The Monte Carlo simulation and standard reference materials, in order to calculate the specific activity from 4 reference materials, and from intercomparison samples were used. The purpose was to evaluate the analytical results obtained in the Laboratorio de Espectroscopia Gamma. (author)

  18. Multiple Silicon Nanowires with Enzymatic Modification for Measuring Glucose Concentration

    Cheng-Chih Hsu

    2015-08-01

    Full Text Available This study fabricated a multiple poly-Si nanowires sensor through a top-down method and immobilized glucose oxidase on the multiple nanowires for determining glucose concentration. The proposed sensor is 340 nm in width and uses five physically identical and parallel nanowires. The sensor contained nanowires of various lengths (3, 5, and 10 μm. Experimental results showed that sensor sensitivity is inversely proportional to nanowire length. The sensor with 3 μm in nanowire length exhibited a theoretical resolution of 0.003 mg/dL and the highest sensitivity of 0.03 μA/(mg/dL. Furthermore, the proposed sensor retains this performance when reused for up to 10 applications.

  19. Surface exposure dating with 10Be, 26Al and 36Cl in the dry valleys, Antarctica and in the Swiss Alps

    By measuring the concentration of a cosmogenic isotope (e.g. 10Be, 26Al, 36Cl), the length of time since formation or uncovering of a rock surface can be determined rather precisely. The useful time range of these isotopes is dependent upon the production rates, the half-lives as well as on sample analysis limitations. The interplay of the various factors is shown by two examples; the dating of very old surfaces in Antarctica and the dating of a Younger Dryas moraine in the Swiss Alps. (author) 1 fig., 3 refs

  20. Energy yield determination of concentrator solar cells using laboratory measurements

    Geisz, John F.; García Vara, Iván; Mcmahon, William E.; Steiner, Myles A.; Ochoa Gómez, Mario; France, Ryan M.; Habte, Aron; Friedman, Daniel J.

    2015-01-01

    The annual energy conversion efficiency is calculated for a four junction inverted metamorphic solar cell that has been completely characterized in the laboratory at room temperature using measurements fit to a comprehensive optoelectronic model of the multijunction solar cells. A simple model of the temperature dependence is used redict the performance of the solar cell under varying temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficie...

  1. He isotope concentrations in groundwater - measurement and interpretation

    While up to now metrological problems obstructed the use of 3He as hydrological tracer, the 4He content of groundwater samples presented difficulties for interpretation. In the framework of this study, first of all, metrological problems in connection with the determination of helium isotope contents in groundwater samples were solved. Then the possibilities and limits of dating measured 3He values could be determined. For the interpretation of the age of 4He contents extended model concepts were used. (orig./RB)

  2. Concentration measurements of biodiesel in engine oil and in diesel fuel

    This work comprised a method for concentration measurements of biodiesel in engine oil as well as biodiesel in diesel fuel by a measurement of the permittivity of the mixture at a frequency range from 100 Hz to 20 kHz. For this purpose a special designed measurement cell with high sensitivity was designed. The results for the concentration measurements of biodiesel in the engine oil and diesel fuel shows linearity to the measurement cell signal for the concentration of biodiesel in the engine oil between 0.5% Vol. to 10% Vol. and for biodiesel in the diesel fuel between 0% Vol. to 100% Vol. The method to measure the concentration of biodiesel in the engine oil or the concentration of biodiesel in the diesel fuel is very accurate and low concentration of about 0.5% Vol. biodiesel in engine oil or in diesel fuel can be measured with high accuracy.

  3. Global Ammonia Concentrations Seen by the 13-years AIRS Measurements

    Warner, Juying; Wei, Zigang; Larrabee Strow, L.; Dickerson, Russell; Nowak, John; Wang, Yuxuan

    2016-04-01

    Ammonia is an integral part of the nitrogen cycle and is projected to be the largest single contributor to each of acidification, eutrophication and secondary particulate matter in Europe by 2020 (Sutton et al., 2008). The impacts of NH3 also include: aerosol production affecting global radiative forcing, increases in emissions of the greenhouse gases nitrous oxide (N2O) and methane (CH4), and modification of the transport and deposition patterns of SO2 and NOx. Therefore, monitoring NH3 global distribution of sources is vitally important to human health with respect to both air and water quality and climate change. We have developed new daily and global ammonia (NH3) products from AIRS hyperspectral measurements. These products add value to AIRS's existing products that have made significant contributions to weather forecasts, climate studies, and air quality monitoring. With longer than 13 years of data records, these measurements have been used not only for daily monitoring purposes but also for inter-annual variability and short-term trend studies. We will discuss the global NH3 emission sources from biogenic and anthropogenic activities over many emission regions captured by AIRS. We will focus their variability in the last 13 years.

  4. Clinical decision support of therapeutic drug monitoring of phenytoin: measured versus adjusted phenytoin plasma concentrations

    Krasowski Matthew D

    2012-02-01

    Full Text Available Abstract Background Therapeutic drug monitoring of phenytoin by measurement of plasma concentrations is often employed to optimize clinical efficacy while avoiding adverse effects. This is most commonly accomplished by measurement of total phenytoin plasma concentrations. However, total phenytoin levels can be misleading in patients with factors such as low plasma albumin that alter the free (unbound concentrations of phenytoin. Direct measurement of free phenytoin concentrations in plasma is more costly and time-consuming than determination of total phenytoin concentrations. An alternative to direct measurement of free phenytoin concentrations is use of the Sheiner-Tozer equation to calculate an adjusted phenytoin that corrects for the plasma albumin concentration. Innovative medical informatics tools to identify patients who would benefit from adjusted phenytoin calculations or from laboratory measurement of free phenytoin are needed to improve safety and efficacy of phenytoin pharmacotherapy. The electronic medical record for an academic medical center was searched for the time period from August 1, 1996 to November 30, 2010 for patients who had total phenytoin and free phenytoin determined on the same blood draw, and also a plasma albumin measurement within 7 days of the phenytoin measurements. The measured free phenytoin plasma concentration was used as the gold standard. Results In this study, the standard Sheiner-Tozer formula for calculating an estimated (adjusted phenytoin level more frequently underestimates than overestimates the measured free phenytoin relative to the respective therapeutic ranges. Adjusted phenytoin concentrations provided superior classification of patients than total phenytoin measurements, particularly at low albumin concentrations. Albumin plasma concentrations up to 7 days prior to total phenytoin measurements can be used for adjusted phenytoin concentrations. Conclusions The results suggest that a measured

  5. Optimization of parameters of single-beam gamma absorption concentration meter within definite measuring range

    Problems of two-parametric optimization of single-beam gamma absorption concentration meters in the assigned measurement range are considered. It is shown that maximum absolute and relative statistical measurement errors are observed at the measurement range boundaries under any values of variable parameters. Optimization of single-beam gamma absorption concentration meter parameters for a number of binary solutions is performed

  6. Investigation of 10Be and its cluster dynamics with the nonlocalized clustering approach

    Lyu, Mengjiao; Ren, Zhongzhou; Zhou, Bo; Funaki, Yasuro; Horiuchi, Hisashi; Röpke, Gerd; Schuck, Peter; Tohsaki, Akihiro; Xu, Chang; Yamada, Taiichi

    2016-05-01

    We extend the concept of nonlocalized clustering to the nucleus 10Be with proton number Z =4 and neutron number N =6 (N =Z +2 ). The Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function is formulated for the description of different structures of 10Be. Physical properties such as energy spectrum and root-mean-square radii are calculated for the first two 0+ states and corresponding rotational bands. With only one single THSR wave function, the calculated results show good agreement with other models and experimental values. We apply, for the first time, the THSR wave function on the chain orbit (σ -orbit) structure in the 02+ state of 10Be. The ring-orbit (π -orbit) and σ -orbit structures are further illustrated by calculating the density distribution of the valence neutrons. We also investigate the nonlocalized dynamics of α clusters and the correlations of two valence neutrons in 10Be.

  7. Investigation of 10Be and its cluster dynamics from nonlocalized clustering concept

    Lyu, Mengjiao; Zhou, Bo; Funaki, Yasuro; Horiuchi, Hisashi; Röpke, Gerd; Schuck, Peter; Tohsaki, Akihiro; Xu, Chang; Yamada, Taiichi

    2015-01-01

    We extend the new concept of nonlocalized clustering to the nucleus 10Be with proton number Z=4 and neutron number N=6 (N=Z+2). The Tohsaki-Horiuchi-Schuck-R\\"opke (THSR) wave function is formulated for the description of different structures of 10Be. Physical properties such as energy spectrum and root-mean-square radii are calculated for the first two 0+ states and corresponding rotational bands. With only one single THSR wave function, the calculated results show good agreement with other models and experimental values. We apply, for the first time, the THSR wave function on the chain orbit ({\\sigma}-orbit) structure in the 0^+_2 state of 10Be. The ring orbit ({\\pi}-orbit) and {\\sigma}-orbit structures are further illustrated by calculating the density distribution of the valence neutrons. We also investigate the dynamics of ff-clusters and the correlations of two valence neutrons in 10Be.

  8. Off-line production of intense 7,10Be+ beams

    7Be and 10Be were produced by 590 MeV proton bombardment of a graphite target at PSI. Parts of this graphite target were transferred into an ISOLDE target and ion source unit and ionized with the ISOLDE resonance ionization laser ion source. Thus intense radioactive ion beams of 300 nA of 7,10Be+ were produced off-line

  9. Accelerator mass spectrometry for analysis of 10Be. Applications in marine geology

    Using the Accelerator Mass Spectrometry the behaviour of long-lived (half time 1.5 Million years) cosmogenic isotopes 10Be in a marine environment was examined. The geochemical behaviour of 10Be in oceans was examined in a water profile of the eastern Atlantic and on sediment cores from the eastern Atlantic and the Antarctica. The retention period in oceans was calculated from the water profile to be 700-1000 years. The examination of sedimentary cores showed, that the 10Be flow into the sediment in areas of high bioproductivity surpasses the production rate. Comparison of 10Be flow with 230Th flow into the examined sedimentary cores showed a period of retention of 10Be in the ocean of only about 400 years. Changes in the sedimentation rate and changes in the mineralogical composition correlate with paleooceanographic events, the start of the Antarctica icing 14 million years ago, changes in the deep water circulation 6.5 million years ago and the icing over of the northern hemisphere 3 million years ago. The same paleooceanographic events find correlation with the inside structure of a total of 16 manganese nodes and crusts from diverse parts of the ocean which were also dated with 10Be. (orig./DG)

  10. Dinucleon correlation of $^9$Li, $^{10}$Be, and $^{9,10}$C

    Kobayashi, Fumiharu

    2013-01-01

    We study the dinucleon (dineutron and diproton) correlation of the ground states of $^9$Li, $^{10}$Be, and $^{9,10}$C. We assume an $\\alpha+t$ core for $^9$Li, an $\\alpha+\\alpha$ core for $^{10}$Be and $^{10}$C, and an $\\alpha+^3$He core for $^9$C, and investigate the effect of core structure changes on the degree of dineutron formation and spatial expansion from the core. For $^9$Li, $t$ cluster breaking in the core significantly enhances the dineutron component inside the nuclei. Moreover, its component markedly depends on the strength of the spin-orbit interaction since a dineutron is fragile and dissociates readily due to the spin-orbit interaction. Compared with $^9$Li, the dineutron of $^{10}$Be dissociates largely due to the stronger spin-orbit attraction from the $\\alpha+\\alpha$ core than the $\\alpha+t$ core. We also investigate diproton features in $^{9,10}$C, the mirror nuclei of $^9$Li and $^{10}$Be, respectively, and compare them with the dineutron features of $^9$Li and $^{10}$Be. No qualitative ...

  11. Measurement of uranium, radium and radon concentration in ground water sampled over Hiroshima prefecture, Japan

    A new method to measure the concentration of uranium and radium in ground water has been developed. One-liter of ground water was evaporated on a Teflon sheet and measured with a low background Ge detector. According to the decay of 238U, radio equilibrium has been achieved between 238U and progeny 234Th after about 150 days. 238U concentration can be determined from the gamma-ray measurement of the dry up sample. Ground water samples were collected from 58 locations in Hiroshima prefecture. Radon concentration was measured directly from the 250 mL water sample. It has been shown that dependence of uranium, radium and radon concentration on the geological map in Hiroshima prefecture. A clear correlation was observed between uranium and radium concentration, but not between uranium and radon concentration. (author)

  12. Evaluation of the atmospheric transport model NIRE-CTM-96 by using measured radon-222 concentrations

    An atmospheric transport model, NIRE-CTM-96, was evaluated by using measured radon-222 concentrations. The model has 2,5x2,5 degree horizontal resolution and 15 vertical levels. Assimilated global meteorological data for 1990-1996 from the European Centre for Medium Range Weather Forecasts were used to drive the model. We used an emanation rate of radon-222 of 1 atom/cm2/s over mostly ice-free land. Simulated concentrations were compared with measured concentrations for 22 sites worldwide including 10 stations in China. Simulated annual mean concentrations for Freiburg, Germany, and Socorro, New Mexico, and for four stations in northern China were consistent with the measured concentrations. Simulated daily concentrations for Ogasawara-Hahajima, Japan, correlated well with the measured concentrations. Simulated upper tropospheric concentrations for Moffet Field, California, demonstrated the cross-Pacific transport from central Eurasia and India-Indochina area. Simulated concentrations for two stations in southern China were almost half of the measured concentrations. Mixing layer depth in the model was consistent with other estimates which indicates higher emanation rate there. Simulated concentrations for the South Indian Ocean and the Antarctic during summer were significantly lower than the measured concentrations; this difference was accounted for when emanation from the ocean at a rate of 0.01 atom/cm2/s was included in the model. The model failed to simulate amplitudes of high-concentration events at Mauna Loa. These high-concentration events were possibly a result of filament-like horizontal structure or laminated vertical structure. The vertical as well as horizontal resolution of the model were supposed to be insufficient to reproduce these fine structures

  13. Measuring free metal ion concentrations in multicomponent solutions using Donnan Membrane Technique

    Kalis, E.J.J.; Temminghoff, E.J.M.; Weng, L.P.; Riemsdijk, van W.H.

    2007-01-01

    Among speciation techniques that are able to measure free metal ion concentrations, the Donnan membrane technique (DMT) has the advantage that it can measure many different free metal ion concentrations simultaneously in a multicomponent sample. Even though the DMT has been applied to several system

  14. Analysis of T=1 10B states analogue to 10 Be cluster states

    Current status of the search for T=1 cluster states in 10Be, 10B [1] and 10C is presented. The best known of the three, 10Be [2-4] has an established rotational band (6.18, 7.54 and 10.15 MeV) with unusually large moment of inertia. Status of their isobaric analogue in 10B is presented, with emphasis on 3He+11Be, 7Li+6Li and 7Be+6,7Li reactions.(author)

  15. Screening measurements of radon concentration levels at a school using passive type radon monitors

    We measured the indoor radon concentration in our school of about 100 rooms using passive type radon monitors. The type of distribution of the radon concentration followed the logarithmic normal type distribution. The average concentration was about 30 Bq/m3, and the geometric average of it was 21 Bq/m3, respectively. The place of highest concentration was the terminal room of the computer center. The radon concentration of that area was about 200 Bq/m3. The second highest place was a closed off shelving room of the school library. The radon concentration values depended on the type of window frames. In the room with aluminum sash window frames, the value was relatively high. We also measured the radon concentration in the bedrooms of students' homes. We asked about 200 students to measure radon concentration in their bedrooms using the same type of radon monitors for six months. The obtained radon concentration also followed logarithmic normal type distribution. The average concentration was 8.6 Bq/m3. The students' home towns are located throughout Ibaraki-prefecture. Using the data, we got an average radon concentration for each of the cities and towns. The average radon concentrations for inland cities and towns were relatively higher than seaside towns. This experiment was a good opportunity to show students the existence of natural radioisotopes in their surroundings. (author)

  16. Screening measurements of radon concentration levels at a school using passive type radon monitors

    Matsuzawa, Takao; Soeta, Takayuki; Mori, Shinji [Ibaraki National Coll. of Technology, Hitachinaka (Japan)] [and others

    1995-01-01

    We measured the indoor radon concentration in our school of about 100 rooms using passive type radon monitors. The type of distribution of the radon concentration followed the logarithmic normal type distribution. The average concentration was about 30 Bq/m3, and the geometric average of it was 21 Bq/m3, respectively. The place of highest concentration was the terminal room of the computer center. The radon concentration of that area was about 200 Bq/m3. The second highest place was a closed off shelving room of the school library. The radon concentration values depended on the type of window frames. In the room with aluminum sash window frames, the value was relatively high. We also measured the radon concentration in the bedrooms of students` homes. We asked about 200 students to measure radon concentration in their bedrooms using the same type of radon monitors for six months. The obtained radon concentration also followed logarithmic normal type distribution. The average concentration was 8.6 Bq/m3. The students` home towns are located throughout Ibaraki-prefecture. Using the data, we got an average radon concentration for each of the cities and towns. The average radon concentrations for inland cities and towns were relatively higher than seaside towns. This experiment was a good opportunity to show students the existence of natural radioisotopes in their surroundings. (author).

  17. Climatic influence in NRM and 10 Be-derived geomagnetic paleointensity data

    2001-01-01

    One can determine geomagnetic paleointensities from natural remanent magnetizations (NRM) and by inverting production rates of cosmogenic isotopes such as 10 Be and 14 C. Recently, two independently derived 200-kyr stacks [Y. Guyodo, J.-P. Valet, Relative variations in geomagnetic intensity from sed

  18. A 30000 yr record of erosion rates from cosmogenic 10Be in middle European river terraces

    Schaller, M.; Blanckenburg, von F.; Veldkamp, A.; Tebbens, L.A.; Hovius, N.; Kubik, P.W.

    2002-01-01

    Cosmogenic 10Be in river-borne quartz sand records a time-integrated erosion rate representative of an entire drainage basin. When sequestered in a terrace of known age, paleo-erosion rates may be recovered from the nuclide content of the terrace material. Paleo-erosion rates between 30 and 80 mm/ky

  19. Analog voltmeter for measuring oxygen concentration in fast reactor sodium circuits

    An analog voltmeter designed for oxygen concentration measurement in the sodium coolant of fast reactors and thus the determination of oxygen corrosion action on the reactor core materials was tested in a sodium loop. The oxygen concentration is determined from the measurements of voltage across a solid electrolyte galvanic cell and of ambient temperature measured by a thermocouple. Thermocouple voltage ranges within 10 and 21 mV while the input from the galvanic cell within 0.2 and 0.45 V. The measured values of both quantities are combined at the analog voltmeter output according to a certain relation shown and give oxygen concentration. (Z.M.)

  20. Photoneutron compensating method for boric acid concentration measuring instrument in heavy water moderated reactor

    In a boric acid concentration measuring instrument in a heavy water moderated reactor, a portion of γ-ray from Na-24 and Mn-56 is reacted with heavy water to form photoneutrons. The photoneutrons cause errors in the measurement for B-10 concentration. Then, in the present invention, a sample liquid containing photoneutron sources is supplied during normal measurement and a sample liquid removed with the photoneutron sources by passing through an ion exchange resin tower is supplied upon calibration of the measuring instrument. Then, the extent for the of effect of neutron sources and γ-nuclides is obtained by calculation from the measuring value to calibration the extent of the photoneutrons. Further, a method of using a counter tube having a Cd filter is used in combination during normal measurement to enable continuous measurement without exchanging the sample liquid. Accordingly, the influence of photoneutrons can be compensated and boric acid concentration can be measured at high accuracy. (N.H.)

  1. RiverPOP 2009: Measuring concentrations of persistent organic pollutants and trace metals in Norwegian rivers.

    Allan, I; Garmo, Ø.; Harman, C.; Kringstad, A.; Bratsberg, E.

    2010-01-01

    A performance evaluation of a range of techniques for the measurement of the concentration of persistent organic pollutants and trace metals was undertaken in the Rivers Glomma and Drammen in 2009. This work focussed on further evaluating techniques that have the potential to substantially improve the reliability and limits of detection of such measurements. Passive sampling techniques were employed to measure dissolved concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphe...

  2. Thermal diffusivity and conductivity of supercooled liquid in Zr41Ti14Cu12Ni10Be23 metallic glass

    Yamasaki, Michiaki; Kagao, Shinya; Kawamura, Yoshihito; Yoshimura, Kenji; カワムラ, ヨシヒト; 河村, 能人

    2004-01-01

    The thermal diffusivity of amorphous solid and supercooled liquid in a Zr41Ti14Cu12Ni10Be23 bulk metallic glass (BMG) and its crystalline counterpart alloy was measured. The studies show that the thermal diffusivity and conductivity of the amorphous solid are weakly temperature dependent, with small positive temperature coefficients. The amorphous solid also showed lower thermal diffusivity and conductivity than the crystalline counterpart alloy. The results also show that the thermal diffusi...

  3. Comparison of venous blood alcohol concentrations and breath alcohol concentrations measured with Draeger Alcotest 9510 DE Evidential.

    Hartung, Benno; Schwender, Holger; Pawlik, Evelyn; Ritz-Timme, Stefanie; Mindiashvili, Nona; Daldrup, Thomas

    2016-01-01

    Most comparisons of blood alcohol concentrations (BAC) and breath alcohol concentrations (BrAC) are either derived from drinking trials with rigid drinking protocols or from investigative authorities' data with considerable time differences between the determination of BAC and BrAC. In general, only comparisons of relatively low BAC-BrAC pairs are available. Therefore, the relationship between BAC and BrAC was examined even for high BAC above 2g/kg. The results of a large-scale drinking test under realistic conditions with 78 test persons and short time intervals between BAC and BrAC measurements are presented. It was shown that the conversion factor Q varies greatly (between 1571:1 and 2394:1) and increases with increasing BAC. A constant conversion factor that is suitable for variable forensic purposes could not be presented. PMID:26654867

  4. Calibration of cosmogenic 3He and 10Be production rates in the High Tropics

    Blard, Pierre-Henri; Martin, Léo; Lavé, Jérôme; Charreau, Julien; Condom, Thomas; Lupker, Maarten; Braucher, Régis; Bourlès, Didier

    2014-05-01

    It is critical to refine both the accuracy and the precision of the in situ cosmogenic dating tool, especially for establishing reliable glacial chronologies that can be compared to other paleoclimatic records. Recent cross-calibrations of cosmogenic 3He in pyroxene and 10Be in quartz [1, 2] showed that, both at low (1300 m) and high elevation (4850 m), the 3He/10Be production ratio was probably ~40% higher than the value of ~23 initially defined in the 90's. This recent update is consistent with the last independent determinations of the sea level high latitude production rates of 10Be and 3He, that are about 4 and 125 at.g-1.yr-1, respectively [e.g. 3, 4]. However, major questions remain about these production rates at high elevation, notably because existing calibration sites for both 3He and 10Be are scarce above 2000 m. It is thus crucial to produce new high precision calibration data at high elevation. Here we report cosmogenic 10Be data from boulders sampled on a glacial fan located at 3800 m in the Central Altiplano (Bolivia), whose age is independently constrained by stratigraphic correlations and radiocarbon dating at ca. 16 ka. These data can be used to calibrate the production rate of 10Be at high elevation, in the Tropics. After scaling to sea level and high latitude, these data yield a sea level high latitude P10 ranging from 3.8 to 4.2 at.g-1.yr-1, depending on the used scaling scheme. These new calibration data are in good agreement with recent absolute and cross-calibration of 3He in pyroxenes and 10Be in quartz, from dacitic moraines located at 4850 m in the Southern Altiplano (22° S, Tropical Andes) [2,5]. The so-obtained 3He/10Be production ratio of 33.3±0.9 (1σ) combined with an absolute 3He production rate locally calibrated in the Central Altiplano, at 3800 m, indeed yielded a sea level high latitude P10 ranging from 3.7±0.2 to 4.1±0.2 at.g-1.yr-1, depending on the scaling scheme [2,5]. These values are also consistent with the 10Be

  5. Energy-dispersive x-ray-fluorescence analysis for on-line uranium-concentration measurement

    An on-line monitor capable of near-real-time measurement of uranium concentrations in process streams has been developed and demonstrated. The monitor, which uses energy dispersive x-ray fluorescence analysis techniques, has been evaluated in the laboratory and in a solvent extraction column study using natural uranium. Concentrations in the range 0.5 to 150 g/l have been measured in both flowing aqueous and organic streams. For streams with uranium concentrations in the range 20 to 150 g/l, data collection times of 300 seconds are sufficient to measure the concentration with less than 2% error. Streams which have lower concentrations require longer data collection times to provide the same measurement error. The results are used for nuclear material inventory and process control

  6. Improvement of dielectrophoretic impedance measurement method by bacterial concentration utilizing negative dielectrophoresis

    Hamada, R [R and D Center, Panasonic Healthcare Co., Ltd., 2131-1, Minanikata, Toon, Ehime (Japan); Takayama, H; Shonishi, Y; Hisajima, T; Mao, L; Nakano, M; Suehiro, J, E-mail: hamada.ryo@jp.panasonic.com [Department of Electrical and Electronic Engineering, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka (Japan)

    2011-08-17

    In this study, the concept design for the improvement of the bacterial detection sensitivity of the DEPIM (Dielectrophoretic Impedance Measurement) method has been proposed. The cells in the micro-chamber are repelled and concentrated by n-DEP (negative dielectrophosesis). The concentrated cells are captured by p-DEP (positive DEP) and detected by measuring the change in the electrical impedance. The numerical simulations and the preliminary test were performed to investigate the effectiveness of the n-DEP concentration. When n-DEP concentration was employed, the increase in the rate of the conductance became approximately two times higher than that obtained without n-DEP.

  7. Improvement of dielectrophoretic impedance measurement method by bacterial concentration utilizing negative dielectrophoresis

    In this study, the concept design for the improvement of the bacterial detection sensitivity of the DEPIM (Dielectrophoretic Impedance Measurement) method has been proposed. The cells in the micro-chamber are repelled and concentrated by n-DEP (negative dielectrophosesis). The concentrated cells are captured by p-DEP (positive DEP) and detected by measuring the change in the electrical impedance. The numerical simulations and the preliminary test were performed to investigate the effectiveness of the n-DEP concentration. When n-DEP concentration was employed, the increase in the rate of the conductance became approximately two times higher than that obtained without n-DEP.

  8. Non-adiabatic dynamics in 10Be with the microscopic alpha+alpha+n+n model

    Ito, M

    2006-01-01

    The alpha+6He low-energy reactions and the structural changes of 10Be in the microscopic alpha+alpha+n+n model are studied by the generalized two-center cluster model with the Kohn-Hulthen-Kato variation method. It is found that, in the inelastic scattering to the alpha+6He(2+) channel, characteristic enhancements are expected as the results of the parity-dependent non-adiabatic dynamics. In the positive parity state, the enhancement originates from the no-adiabatic eigenstate generated by the radial excitation of the relative motion between two alpha-cores. On the other hand, the enhancement in the negative parity state is induced by the Landau-Zener level-crossing. These non-adiabatic processes are discussed in connection to the formation of the inversion doublet in the compound system of 10Be.

  9. Effects of collective modes on shell structure of 10Be and 24O core

    We study the effects of collective modes on shell structure in nuclei near the neutron drip line close to 10Be and 24O. Energy shifts in single-particle energies are evaluated by a particle-vibration coupling model. In the case of the 10Be core, the coupling to 2+ states is found to reduce the shell gap between 2s1/2 and 1p1/2 states. In the case of the 24O core, the couplings to 3- and 2+ states lead to a large energy gap between 2s1/2 and 1d3/2 states, in agreement with a recent experimental evidence of a new magic number at N=16 near the neutron drip line. In particular, the 3- vibrations are found to play a crucial role to push down the energy of the 2s1/2 state

  10. A new technique for measuring the concentrations of airborne radon progeny by using an imaging plate

    A new technique was developed for measuring the concentrations of airborne radon progeny by using an imaging plate (IP). The concentrations of radon progeny collected on the sampling filter were measured with the IP at 2-5-, 6-20- and 21-30-min intervals after sampling, and the alpha disintegrations were automatically counted by a self-developed image analysis software. To reduce the overlapping impact on alpha counts, a plastic separator with a 0.5-mm thickness was set between the sampling filter and the IP. The lower limit of detection for the equilibrium equivalent concentration of radon was estimated to be ∼3.5 Bq m-3 for a 10-min sampling at 10 l min-1. Comparison experiments showed that results measured with the new technique were well consistent with those measured with the alpha spectrometer. It indicates that the new technique is a useful method for accurate measurements of airborne radon progeny concentrations. (authors)

  11. Quasimolecular states in the interaction of the 11Be + 10Be system

    Quasimolecular states induced by the scattering of 11Be on 10Be are investigated by using the coupled-reaction-channel (CRC) method with the basis functions concerned with the weakly bound valence neutron states in 11Be. As a consequence of very strong CRC effects sharp resonances are predicted as fine structure of the fusion cross section at energies below and near the Coulomb barrier. (author)

  12. Home built equipment for measuring Hall coefficient and charge carrier concentration, mobility and resistivity

    Borup, Kasper Andersen; Christensen, Mogens; Blichfeld, Anders Bank; Johnsen, Simon; Toberer, Eric; Snyder, G. Jeffrey

    2011-01-01

    system, the Quantum Design, Physical Properties Measurement System (PPMS). Measurements on samples with different resistivity and charge carrier concentration will be shown, covering both ends of the interval of samples we are able to measure as well as the range normally observed for thermoelectrics......We present here a home built setup for measuring the specific resistivity, hall coefficient, and charge carrier concentration and mobility at elevated temperatures. The system is optimized for measurements of samples ranging between doped semiconductors and high resistivity metals and uses the van...

  13. Dating Antarctic soils using atmosphere-derived 10Be and nitrate

    Because they are slow forming, Antarctic soils have the potential to yield considerable climatic information from the past c.20 m.y. However, these soils have proved difficult to date absolutely by conventional means. Here we present a novel approach to the problem, based on atmosphere-derived 10Be and nitrate contents. In situations where medium to long term deposition rates can be reasonably estimated from ice core data, the total nitrate inventory in an Antarctic soil can place constraints on its formation age. 10Be radioactive decay may then be used, assuming steady state equilibrium, to further refine the age profile. We have applied such models to a complex soil from the Taylor Valley region in South Victoria Land, deriving an overall nitrate inventory age of c. 18 Ma, and 10Be decay ages for the upper and middle layers of c.15 and c.17 Ma, respectively. These results are consistent with the >10 Ma age of the soil deduced from stratigraphic and geomorphological information. (author). 28 refs., 4 figs., 2 tabs

  14. Development and applications of a multibeam intstrument for DOAS tomographic measurements of two dimensional concentration distributions

    First tomographic Long path DOAS (LP-TOM-DOAS) measurements were performed at the motorway A656. Sequential measurements along 16 light paths were conducted with two LP DOAS instruments. Two dimensional concentration distributions of NO2, SO2 und O3 perpendicular to the motorway were reconstructed from the measurements. For the reconstructions the measurement data were averaged over 5-7 hours. The spatial resolution depends on the number of light paths. The temporal resolution depends on the number of light paths measured simultaneously. A new LP DOAS instrument was developed to improve both. The new instrument is called Multibeam Instrument. It allows the simultaneous measurement along 1 to 6 light beams. The detection limits achieved with this instrument are comparable to those of a conventional LP DOAS instrument. During a test campaign and during the FORMAT II campaign successful measurements with Multibeam instruments were performed. In the LP-TOM-DOAS test campaign well known concentration distributions of NO2 were measured with a measurement setup consisting of 39 light paths and three Multibeam instruments. The reconstructed concentration distributions agree well with the real concentration distributions, for example the real and reconstructed concentration in the measurement area differ by less then 20%. (Orig.)

  15. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO2) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO2) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO2 and HHb, total haemoglobin concentration and SO2. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l-1 (±58 μM) and ±4

  16. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul [Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, London WC1E 6BT (United Kingdom)

    2007-01-07

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO{sub 2}) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO{sub 2}) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO{sub 2} and HHb, total haemoglobin concentration and SO{sub 2}. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of {+-}3

  17. Measurement of concentration of sugar in solutions with laser speckle decorrelation

    Mahajan, Swapnil; Trivedi, Vismay; Chhaniwal, Vani; Prajapati, Mahendra; Zalevsky, Zeev; Javidi, Bahram; Anand, Arun

    2015-05-01

    Measurement of rotation of plane of polarization of linearly polarized light can provide information about the concentration of the optically active system with which it interacts. For substances containing sugar, accurate measurement of rotation of linearly polarized light can provide quantitative information about concentration of sugar in the material. Measurement of sugar concentration is important in areas ranging from blood sugar level measurement in body fluids to measurement of sugar concentrations in juices and other beverages. But in many of these cases, the changes introduced to the state of polarization considering a sample of practical proportion is low and the measurement of low optical rotations becomes necessary. So methods with higher sensitivity, accuracy and resolution need to be developed for the measurement of low optical rotations. Here we describe the development of a compact, low cost, field portable, device for rotation sensing leading to sugar concentration measurements, using speckle de-correlation technique. The developed device measures rotations by determining the changes occurring to a speckle pattern generated by a laser beam passing through the medium under investigation. The device consists of a sample chamber, a diode laser module, a ground glass diffuser and a digital sensor for recording of laser speckle patterns. The device was found to have high resolution and sensitivity.

  18. Radium concentration measurements in coal fly ash and cement samples using LR-115 plastic track detectors

    The increase interest in measuring radium (226Ra) concentration in coal, fly ash and cement is due to its health hazards and environmental pollution. Samples of coal and fly ash from different thermal power stations in northern India were collected and analysed for radium concentration. Cement samples were collected from National Council for Cement and Building Materials (NCB), Ballabgarh (Haryana). The radium concentration is estimated through track etch technique using LR-115 CN detectors. (author)

  19. Gradient SiNx IBAD coating: preparation and measurement of concentration profile

    Preparation of gradient SiNx coating by the ion beam assisted deposition method with high ion energy is described. Special shape of the concentration of nitrogen in the coating was chosen and constructed. Concentration profile was constructed in three steps with different ratios of nitrogen and silicon atom fluxes. Ion energy was 90 keV. Concentration profile was measured by RBS (Rutherford Back Scattering) method. (author). 1 ref., 2 figs

  20. Variation in acrylamide concentration in French fries : effects of control measures in food service establishments

    Sanny, M.A.I.

    2012-01-01

    The aim of this thesis was first to identify the major technological and managerial factors and to investigate their contribution to variation in acrylamide concentrations.  The second aim was to investigate the effect of technological and managerial control measures on the concentration and variation of acrylamide in the preparation of French fries in food service establishments (FSE).  The variation ininitial concentration of reducing sugars, variable frying conditions and food ha...

  1. Measurements of the oxidation state and concentration of plutonium in interstitial waters of the Irish Sea

    The question of plutonium movement in interstitial waters resulting from diffusion along concentration gradients or from advective flow is addressed. The results of measurements of both the concentration and the oxidation state of plutonium in interstitial water collected from sediments near the Windscale discharge, in the solid phases of these sediments and in seawater and suspended solids collected at the coring locations are discussed

  2. Airborne plutonium-239 and americium-241 concentrations measured from the 125-meter Hanford Meteorological Tower

    Airborne plutonium-239 and americium-241 concentrations and fluxes were measured at six heights from 1.9 to 122 m on the Hanford meteorological tower. The data show that plutonium-239 was transported on nonrespirable and small particles at all heights. Airborne americium-241 concentrations on small particles were maximum at the 91 m height

  3. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  4. Prompt gamma-ray spectrometry for measurement of B-10 concentration in brain tissue and blood

    Boron-10 (B-10) concentration in the brain tissue and blood was measured continuously for 24 hours after injection of the B-10 compound in live rabbits using prompt gamma-ray spectrometry. Following injection of B-10 compound (Na2B12H11SH, 50mg/kg) dissolved in physiological saline, B-10 concentration was continuously measured in the brain tissue. Intermittently the concentration of B-10 in blood and cerebro-spinal fluid (CSF) was also measured. In 10 minutes after the injection of B-10 compound, the level of B-10 concentration reached the peak of 400-500 ppm in blood and 20-30 ppm in the normal brain tissue. In 60 minutes the level of B-10 concentration rapidly decreased and then a gradual decline was observed. The value was 15-30 ppm at 3 hours after injection, 5-10 ppm at 6 hours and 2-5 ppm at 24 hours in the blood. The concentration in the brain tissue was 3-8 ppm at 3 hours, 2-5 ppm at 6 hours and below 1.5 ppm at 24 hours. B-10 concentration in cerebro-spinal fluid was below 1 ppm. B-10 concentration was also measured in the brain tumor and blood in the human cases at boron neutron capture therapy (BNCT). These data studied by prompt gamma-ray spectrometry are very important and useful to decide the irradiation time. (author)

  5. Measurement the concentration of radon in the flats of Pristina, Kosovo polja and their surroundings

    By using the solid state track detectors is made the measurements of the radon concentration in the flats on the Pristina area and its closed surroundings. The concentration of the radon was under 150 Bq/m3 but in the same places its amount is between 150 Bq/m3 and 750 Bq/m3. (author)

  6. Optimisation of elevated radon concentration measurement by using electro-chemical etching of nuclear track detectors

    In the paper, two methods for adjusting of passive radon-thoron discriminative dosimeters (UFO detector) for enhanced radon concentration measurement are presented. Achieved upper limit of detection is 5.94 MBq m-3 d

  7. Measurements of superequilibrium hydroxyl concentrations in turbulent nonpremixed flames using saturated fluorescence

    Drake, M. C.; Pitz, R. W.; Lapp, M.; Fenimore, C. P.; Lucht, R. P.

    1985-01-01

    The first quantitative, time- and space-resolved measurements have been obtained for probability density functions of OH concentration in nonpremixed flames. Measurements using single-pulse, laser-saturated fluorescence in laminar, transitional, and turbulent nonpremixed H2-air flames provide unambiguous evidence for substantial OH superequilibrium concentrations, in qualitative agreement with predictions of laminar and turbulent combustion models. The average degree of superequilibrium, OH/OH(AE), is typically 4-5 near the jet exit and approaches unity far downstream. The maximum instantaneous OH concentration measured in transitional and turbulent H2-air flames is about 6 x 10 to the 16th molecules/cc, in accord with the maximum determined by partial equilibrium thermodynamic calculations and with the maximum OH concentrations measured in premixed H2-air flames.

  8. Measurement techniques of thoron and thoron progeny concentrations. Active and passive methods and their calibrations

    The measurements of 220Rn and its progeny concentrations are affected always by 222Rn and its progeny. Various types of measurement techniques of 220Rn and its progeny concentrations had been developed by using the differences between half lives of 222Rn and 220Rn and energies of α- and γ-radiations emitted from 222Rn and 220Rn progeny. Active 220Rn measurement techniques include the methods of ionization chamber, scintillation cell, two filter, liquid scintillation and activated charcoal. Decay, α-spectroscopy and integrating methods have used to measure 220Rn progeny concentrations collected on a filter. Passive monitors are suitable to survey mean 220Rn concentration in the living environment. Cup and activated charcoal monitors have been reported for the passive 220Rn methods. Calibrations of active and passive 220Rn monitors should be carried out in the calibration chambers with 220Rn source outside and inside, respectively. (author)

  9. Optical tweezing electrophoresis of single biotinylated colloidal particles for avidin concentration measurement

    Brans, Toon; Strubbe, Filip; Schreuer, Caspar; Neyts, Kristiaan; Beunis, Filip

    2015-06-01

    We present a novel approach for label-free concentration measurement of a specific protein in a solution. The technique combines optical tweezers and microelectrophoresis to establish the electrophoretic mobility of a single microparticle suspended in the solution. From this mobility measurement, the amount of adsorbed protein on the particle is derived. Using this method, we determine the concentration of avidin in a buffer solution. After calibration of the setup, which accounts for electro-osmotic flow in the measurement device, the mobilities of both bare and biotinylated microspheres are measured as a function of the avidin concentration in the mixture. Two types of surface adsorption are identified: the biotinylated particles show specific adsorption, resulting from the binding of avidin molecules with biotin, at low avidin concentrations (below 0.04 μg/ml) while at concentrations of several μg/ml non-specific on both types of particles is observed. These two adsorption mechanisms are incorporated in a theoretical model describing the relation between the measured mobility and the avidin concentration in the mixture. This model describes the electrophoretic mobility of these particles accurately over four orders of magnitude of the avidin concentration.

  10. A 10Be Chronology of Late Pleistocene and Holocene Glaciation in the Rwenzori Mountains, Uganda

    Baber, M.; Kelly, M. A.; Russell, J. M.; Loomis, S. E.

    2012-12-01

    Although the retreat of glaciers in East Africa has been monitored over the last century, longer-term records of African glacier fluctuations are scarce. The Rwenzori Mountains, located on the border of Uganda and the Democratic Republic of Congo, host the largest glacial system in Africa and provide an opportunity for extensive investigation of past glaciations. We mapped and applied surface exposure (10Be) dating to glacial moraines deposited since the end of the last ice age in the Rwenzori Mountains to test the feasibility of 10Be dating at this site and to develop a chronology of glacial fluctuations. Our study is the first to use 10Be dating of glacial features in Africa and is possible because the Rwenzori host quartz-rich lithologies. By comparing the timing of Rwenzori glacial advances with other paleoclimate records from East Africa, we also will examine the climatic conditions which influenced tropical glacier fluctuations. Osmaston (1989) mapped moraines in the Rwenzori Mountains, documenting three stages of Pleistocene and Holocene glaciations, the Mahoma, Omurubaho and Lac Gris stages. The Mahoma stage moraines are estimated to be older than 17,980 ± 780 yr BP (D. M. Livingstone, 1962) by basal 14C dating of sediments from Lake Mahoma, situated in large lateral moraine at 2990 m asl. The age of the Omurubaho stage moraine is estimated from a basal 14C age (7,730 ± 150 yr BP) Lower Kitandara Lake (3990 m asl) and dammed by an Omurubaho stage moraine. The Lac Gris moraines are estimated at ~150-700 yr BP (de Heinzelin, 1953; Bergström, 1955) based on rates of lichen growth and plant colonization on moraines about 200 m below current glacial positions on Mt. Stanley. Though considerable uncertainty remains for the ages of these glacier deposits, these three stages most likely represent ages from the LGM to the LIA. We present two new 10Be ages of boulders from two moraines in the Nyamagusani Valley, ~4000 m asl. Sample KOP-2 (4033 m asl) is from the

  11. Cosmogenic 10Be constraints on Little Ice Age glacial advances in the eastern Tian Shan, China

    Li, Yanan; Li, Yingkui; Harbor, Jon; Liu, Gengnian; Yi, Chaolu; Caffee, Marc W.

    2016-04-01

    Presumed Little Ice Age (LIA) glacial advances, represented by a set of fresh, sharp-crested, boulder covered and compact moraines a few hundred meters downstream from modern glaciers, have been widely recognized in the Central Asian highlands. However, few studies have constrained the formation ages of these moraines. We report 31 10Be exposure ages from presumed LIA moraines in six glacial valleys in the Urumqi River headwater area and the Haxilegen Pass area of the eastern Tian Shan, China. Our results reveal that the maximum LIA glacial extent occurred mainly around 430 ± 100 yr, a cold and wet period as indicated by proxy data from ice cores, tree rings, and lake sediments in Central Asia. We also dated a later glacial advance to 270 ± 55 yr. However, 10Be exposure ages on several presumed LIA moraines in front of small, thin glaciers are widely scattered and much older than the globally recognized timing of the LIA. Historical topographic maps indicate that most glaciers were more extensive in the early 1960s, and two of our 10Be sample sites were located close to the ice front at that time. Boulders transported by these small and thin glaciers may be reworked from deposits originally formed prior to the LIA glacial advances, producing apparently old and widely scattered exposure ages due to varied nuclide inheritance. Other published ages indicated an earlier LIA advance around 790 ± 300 yr in the easternmost Tian Shan, but in our study area the more extensive advance around 430 ± 100 yr likely reworked or covered deposits from this earlier event.

  12. {sup 10}Be in rhodochrosite nodules from Neogene sediments along the Galapagos Ridge, equatorial Pacific

    Aldahan, A., E-mail: ala.aldahan@geo.uu.s [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); Department of Geology, United Arab Emirates University, Al Ain (United Arab Emirates); Morad, S. [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); Department of Petroleum Geosciences, Petroleum Institute, Abu Dhabi (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, Uppsala (Sweden); Sturesson, U. [Department of Earth Sciences, Uppsala University, Uppsala (Sweden); ElSaiy, A. [Department of Geology, United Arab Emirates University, Al Ain (United Arab Emirates)

    2010-04-15

    Microcrystalline, calcian rhodochrosite occurs as nodules around burrows in late Neogene pelagic sediments from the Galapagos Ridge in the Guatemala Basin, eastern equatorial Pacific (DSDP Leg 68; Site 503). {sup 10}Be isotope revealed that the rhodochrosite nodules have formed under growth conditions much faster than those reported for Fe-Mn nodules. The overall REE patterns of the nodules and host pelagic sediments indicate element derivation mainly from marine pore water. However, variations in the shale normalised Eu values suggest influx of hydrothermal fluids into mounds area at Galapagos, which is also evidenced by the similar minor and major element contents in the nodules and host sediments.

  13. Influence of model resolution on the atmospheric transport of 10Be

    A. M. Smith

    2012-07-01

    Full Text Available Understanding the transport path of the solar activity proxy 10Be from source to archive is crucial for the interpretation of its observed variability. The extent of mixing of the strong production signal has been quantified in a previous study (Heikkilä et al., 2009. In this study we perform sensitivity studies to investigate the influence of model resolution on the level of mixing and transport path of 10Be in the atmosphere using the ECHAM5-HAM aerosol-climate model. This study permits us to choose an acceptable resolution, and so minimum CPU time, to produce physically accurate reconstructions. Four model resolutions are applied: T21L19: a coarse horizontal and vertical resolution with model top at ca. 30 km, T42L31: an average horizontal and fine vertical one, T42L39: similar vertical resolution than L19 but including the middle atmosphere up to ca. 80 km and T63L47: a fine resolution horizontally and vertically with middle atmosphere. Comparison with observations suggests that a finer vertical resolution might be beneficial, although the spread between observations was much larger than between the four model runs. A full validation of the resolutions is not possible with the limited number of observations available. In terms of atmospheric mixing the differences became more distinguishable. All resolutions agreed that the main driver of deposition variability is the stratospheric 10Be (total contribution 68% which is transported into the troposphere at latitudes 30–50°. In the troposphere the model resolutions deviated largely in the dispersion of the stratospheric component over latitude. The finest resolution (T63L47 predicted the least dispersion towards low latitudes but the most towards the poles, whereas the coarsest resolution (T21L19 suggested the opposite. The tropospheric components of 10Be differed less between the four model runs. The largest differences were found in the polar tropospheric components, which contribute the

  14. Isovector and isoscalar dipole excitations in $^{9}$Be and $^{10}$Be studied with antisymmetrized molecular dynamics

    Kanada-En'yo, Yoshik

    2015-01-01

    Isovector and isoscalar dipole excitations in $^9$Be and $^{10}$Be are investigated in the framework of antisymmetrized molecular dynamics, in which angular-momentum and parity projections are performed. In the present method, 1p-1h excitations on the ground state and large amplitude $\\alpha$-cluster mode are incorporated. The isovector giant dipole resonance (GDR) in $E>20$ MeV shows the two peak structure which is understood by the dipole excitation in the 2$\\alpha$ core part with the prolate deformation. Because of valence neutron modes against the $2\\alpha$ core, low-energy E1 resonances appear in $E20$ MeV.

  15. Cosmogenic 10Be Exposure Age for the Cut Bank Creek terminal moraine, Glacier National Park, MT

    Quirk, B.; Laabs, B. J.; Leonard, E. M.; Caffee, M. W.

    2012-12-01

    Mountain glaciers are highly sensitive to temperature and precipitation with geologic records that are superb proxies of climate change. In the Rocky Mountains of the western United States, abundant records of Late Pleistocene glaciation provide an opportunity for understanding paleoclimate throughout this region, especially in places where the chronology of glaciation is precisely known. Cosmogenic 10Be exposure dating has been widely applied to glacial deposits in the Rocky Mountains, providing precise numerical ages and improving the understanding of glacial chronologies in this region. Despite these improvements, the chronology of the last Pleistocene glaciation of the northernmost Rocky Mountains is not completely understood. Cosmogenic 10Be exposure dating was applied to the Cut Bank Creek valley in the Lewis Range of the Northern Rocky Mountains, where a discrete mountain glacier deposited a broad terminal moraine during the last Pleistocene glaciation. Exposure ages of eight quartzite and sandstone boulders at the crest of the ice-distal sector of the terminal moraine indicate that abandonment occurred at 15.6 ± 0.8 ka. This age is consistent with age limits of several terminal moraines elsewhere in the Northern Rocky Mountains, suggesting that the last Pleistocene glaciation culminated in this region after the global Last Glacial Maximum.

  16. Application of OSL and 10Be techniques to the establishment of deglaciation chronology in Estonia

    The deglaciation history of Estonia has been under research for about a century. Despite the great number of publications devoted to this subject and marked improvements in study methods, many problems of topical interest have not been solved yet, especially due to the lack of good direct dating methods. In this paper the suitability of OSL and 10Be dating techniques for establishing accurate deglaciation chronology for Estonia is assessed. Turbidity and water depth, velocity of outwash streams and transport length, possible fast sedimentation at night hours or below the ice, incorporation of older, unbleached particles, and other factors affected the extent of the bleaching of the TL signal in different ways, causing great variability of dates. Surface inclination, height of the surface over ground, snow and vegetation cover, and evolution of water bodies influenced the calculation of reliable exposure ages of objects dated using the 10Be method. It means that age determinations of both glaciofluvial deposits with the OSL method and erratic boulders with the 1Be method are highly problematic, especially for glaciofluvial intertill sediments where the exact genesis of deposits is unknown and for boulders, which have been in the forest, under the waters of proglacial lakes and/or the Baltic Sea, or under snow cover for a long time. (author)

  17. Chromatographic method of measurement of helium concentration in underground waters for dating in hydrological questions

    Research methods which use natural environmental indicators are widely applied in hydrology. Different concentrations of indicators and their isotopic components in ground waters allow to determine the genesis of waters and are valuable source of information about the water flow dynamics. One of the significant indicator is helium. The concentration of 4He (helium) in ground water is a fine indicator in water dating in a range from a hundreds to millions of years (Aeschbach-Hertig i in., 1999; Andrews i in., 1989; Castro i in., 2000; Zuber i in., 2007). 4He is also used for dating young waters of age about 10 years (Solomon i in., 1996). Thesis consist the description of elaborated in IFJ PAN in Krakow chromatographic measurement method of helium concentration in ground waters in aim of dating. Chapter 1 contain short introduction about ground water dating and chapter 2 description of helium property and chosen applications of helium for example in technology and earthquake predictions. Helium sources in ground waters are described in chapter 3. Helium concentration in water after infiltration (originated from atmosphere) to the ground water system depends mainly on the helium concentration coming from the equilibration with the atmosphere increased by additional concentration from '' excess air ''. With the increasing resistance time of ground water during the flow, radiogenic, non-atmospheric component of helium dissolves also in water. In chapter 4 two measurement methods of helium concentration in ground waters were introduced: mass spectrometric and gas chromatographic method. Detailed description of elaborated chromatographic measurement method of helium concentration in ground water contain chapter 5. To verify developed method the concentration of helium in ground waters from the regions of Krakow and Busko Zdroj were measured. For this waters the concentrations of helium are known from the earlier mass spectrometric measurements. The results of

  18. Measurement of Radon concentration in groundwater by technique of nuclear track detector

    A method for measuring radon concentration in groundwater using nuclear track detector LR-115 stripping is reported. The radon-monitoring device in groundwater is a small box with two pieces of nuclear track detector and all these materials is placed in a plastic bag made by polyethylene. It is very suitable to measure radon concentration in groundwater well in long term. Alpha tracks produced by radon and it daughter on nuclear track detector is counted automatically by spark counting method. The paper also presents some results of radon concentration in some groundwater well and mineral water sources. (author)

  19. IR detector for hydrocarbons concentration measurement in emissions during petroleum and oil products storage and transportation

    Vasilyev, Andrey O.; Shemanin, Valeriy G.; Chartiy, Pavel V.

    2011-10-01

    A double beam IR detector is developed for light hydrocarbons concentration measurement in emissions from storage vessels during oil and oil products storage and transportation. It was concluded on the basis of chromatogram that main crude losses from evaporation are the share of hydrocarbons light ends from methane to decane. Detector operation is based on spectral transparency measurement in the infrared spectra absorption range. Operational wavelength of infrared radiation makes 3.4 μm. measurement principle is based on concentration calculation proceed from molecule absorption cross-section, optical path length between light emitted diode and reference and signal photodiodes as well as from value of measured signal transmitted through gaging volume. The novel of offering device is an actual paraffin hydrocarbons concentration measurement in emissions and continuous and automatic environment quality control.

  20. Deciphering the Glacial-Interglacial Landscape History in Greenland Based on Markov Chain Monte Carlo Inversion of Existing 10Be-26Al Data

    Strunk, Astrid; Knudsen, Mads Faurschou; Larsen, Nicolaj Krog;

    investigate the landscape history in eastern and western Greenland by applying a novel Markov Chain Monte Carlo (MCMC) inversion approach to the existing 10Be-26Al data from these regions. The new MCMC approach allows us to constrain the most likely landscape history based on comparisons between simulated...... the landscape history in previously glaciated terrains may be difficult, however, due to unknown erosion rates and the presence of inherited nuclides. The potential use of cosmogenic nuclides in landscapes with a complex history of exposure and erosion is therefore often quite limited. In this study, we...... and measured cosmogenic nuclide concentrations. It is a fundamental assumption of the model approach that the exposure history at the site/location can be divided into two distinct regimes: i) interglacial periods characterized by zero shielding due to overlying ice and a uniform interglacial erosion rate...

  1. Measurement of radon concentration in some water samples belonging to some adjoining areas of Pathankot, Punjab

    The study of radon concentration was measured in some areas of Pathankot district, Punjab, India, from the health hazard point of view due to radon. The exposure to radon through drinking water is largely by inhalation and ingestion. RAD 7, an electronic solid state silicon detector (Durridgeco., USA) was used to measure the radon concentration in drinking water samples of the study area. The recorded values of radon concentration in these water samples are below the recommended limit by UNSCEAR and European commission. The recommended limit of radon concentration in water samples is 4 to 40 Bq/l given by UNSCEAR [1] and European commission has recommended the safe limit for radon concentration in water sample is 100 Bq/l [2

  2. The accuracy of radon and thoron progeny concentrations measured through air filtration

    The accuracy and the optimization of determining radon and thoron progeny concentrations in air using air filtration followed by alpha activity measurements were investigated in details. The effects of radon and thoron concentrations, filtering duration and the choice of measuring intervals on relative standard deviations were analyzed. Obtaining satisfactory results by this method should be expected only in the case of high radon and thoron progeny concentrations in air. The optimization process also showed up to be dependent on the progeny concentration. Determinant of the system matrix and its effect on the sensitivity of the results were investigated. - Highlights: • Air filtration followed by total alpha counting was studied. • The method is not recommendable in the case of low progeny concentrations. • Relative standard deviations of each progeny were considered. • System determinant was investigated as the indicator of system stability

  3. Assessment of Average Tracer Concentration Approach for Flow Rate Measurement and Field Calibration

    P. Sidauruk

    2015-12-01

    Full Text Available Tracer method is one of the methods available for open channel flow rate measurements such as in irrigation canals. Average tracer concentration approach is an instantaneous injection method that based on the average tracer concentrations value at the sampling point. If the procedures are correct and scientific considerations are justified, tracer method will give relatively high accuracy of measurements. The accuracy of the average tracer concentration approach has been assessed both in laboratory and field. The results of accuracy tests of open channel flow that has been conducted at the Center for Application Isotopes and Radiation Laboratory-BATAN showed that the accuracy level of average concentrations approach method was higher than 90% compared to the true value (volumetric flow rate. The accuracy of average tracer concentration approach was also assessed during the application of the method to measure flow rate of Mrican irrigation canals as an effort to perform field calibration of existing weirs. Both average tracer concentration approach and weirs can predict the trend of the flow correctly. However, it was observed that flow discrepancies between weirs measurement and average tracer concentration approach predictions were as high as 27%. The discrepancies might be due to the downgrading performances of the weirs because of previous floods and high sediment contents of the flow

  4. 36Cl and 53Mn in Antarctic meteorites and 10Be-36Cl dating of Antarctic ice

    Cosmic-ray-produced 53Mn (tsub(1/2)=3.7x106 years) has been measured in twenty Antarctic meteorites by neutron activation analysis. 36Cl (tsub(1/2)=3.0x105 years) has been measured in fourteen of these objects by tandem accelerator mass spectrometry. Cosmic ray exposure ages and terrestrial ages of the meteorites are calculated from these results and from gases. 14C (tsub(1/2)=5740 years) and 26Al(tsub(1/2)=7.2x105 years) data. The terrestrial ages range from 3x104 to 5x105 years. Many of the L3-Allan Hills chrondrites seem to be a single fall based on these results. In addition, 10Be (tsub(1/2)=1.6x106 years) and 36Cl have been measured in six Antarctic ice samples. The first measurements of 10Be/36Cl ratios in the ice core samples demonstrate a new dating method for ice. (orig.)

  5. Comparing model and measured ice crystal concentrations in orographic clouds during the INUPIAQ campaign

    Farrington, Robert J.; Connolly, Paul J.; Lloyd, Gary; Bower, Keith N.; Flynn, Michael J.; Gallagher, Martin W.; Field, Paul R.; Dearden, Chris; Choularton, Thomas W.

    2016-04-01

    This paper assesses the reasons for high ice number concentrations observed in orographic clouds by comparing in situ measurements from the Ice NUcleation Process Investigation And Quantification field campaign (INUPIAQ) at Jungfraujoch, Switzerland (3570 m a.s.l.) with the Weather Research and Forecasting model (WRF) simulations over real terrain surrounding Jungfraujoch. During the 2014 winter field campaign, between 20 January and 28 February, the model simulations regularly underpredicted the observed ice number concentration by 103 L-1. Previous literature has proposed several processes for the high ice number concentrations in orographic clouds, including an increased ice nucleating particle (INP) concentration, secondary ice multiplication and the advection of surface ice crystals into orographic clouds. We find that increasing INP concentrations in the model prevents the simulation of the mixed-phase clouds that were witnessed during the INUPIAQ campaign at Jungfraujoch. Additionally, the inclusion of secondary ice production upwind of Jungfraujoch into the WRF simulations cannot consistently produce enough ice splinters to match the observed concentrations. A flux of surface hoar crystals was included in the WRF model, which simulated ice concentrations comparable to the measured ice number concentrations, without depleting the liquid water content (LWC) simulated in the model. Our simulations therefore suggest that high ice concentrations observed in mixed-phase clouds at Jungfraujoch are caused by a flux of surface hoar crystals into the orographic clouds.

  6. Sequential Measurement of Intermodal Variability in Public Transportation PM2.5 and CO Exposure Concentrations.

    Che, W W; Frey, H Christopher; Lau, Alexis K H

    2016-08-16

    A sequential measurement method is demonstrated for quantifying the variability in exposure concentration during public transportation. This method was applied in Hong Kong by measuring PM2.5 and CO concentrations along a route connecting 13 transportation-related microenvironments within 3-4 h. The study design takes into account ventilation, proximity to local sources, area-wide air quality, and meteorological conditions. Portable instruments were compacted into a backpack to facilitate measurement under crowded transportation conditions and to quantify personal exposure by sampling at nose level. The route included stops next to three roadside monitors to enable comparison of fixed site and exposure concentrations. PM2.5 exposure concentrations were correlated with the roadside monitors, despite differences in averaging time, detection method, and sampling location. Although highly correlated in temporal trend, PM2.5 concentrations varied significantly among microenvironments, with mean concentration ratios versus roadside monitor ranging from 0.5 for MTR train to 1.3 for bus terminal. Measured inter-run variability provides insight regarding the sample size needed to discriminate between microenvironments with increased statistical significance. The study results illustrate the utility of sequential measurement of microenvironments and policy-relevant insights for exposure mitigation and management. PMID:27182735

  7. Optical measurement of slurry concentration profile in a concurrent-flow gas-slurry column

    An optical technique is described which allows the measurement of steady-state slurry concentration profile in a slender concurrent-flow gas-slurry bubble column. The optically measured profile is compared with that predicted by a previously reported semiempirical dispersion model. Qualitative agreement is observed between them, and the reliability of the technique is supported by additional experimental data

  8. A multiple path photonic lab on a chip for parallel protein concentration measurements.

    Rodríguez-Ruiz, Isaac; Conejero-Muriel, Mayte; Ackermann, Tobias N; Gavira, José A; Llobera, Andreu

    2015-02-21

    We propose a PDMS-based photonic system for the accurate measurement of protein concentration with minute amounts of the sample. As opposed to the state of the art approach, in the multiple path photonic lab on a chip (MPHIL), analyte concentration or molar absorptivity is obtained with a single injection step, by performing simultaneous parallel optical measurements varying the optical path length. Also, as opposed to the standard calibration protocol, the MPHIL approach does not require a series of measurements at different concentrations. MPHIL has three main advantages: firstly the possibility of dynamically selecting the path length, always working in the absorbance vs. concentration linear range for each target analyte. Secondly, a dramatic reduction of the total volume of the sample required to obtain statistically reliable results. Thirdly, since only one injection is required, the measurement time is minimized, reducing both contamination and signal drifts. These characteristics are clearly advantageous when compared to commercial micro-spectrophotometers. The MPHIL concept was validated by testing three commercial proteins, lysozyme (HEWL), glucose isomerase (d-xylose-ketol-isomerase, GI) and Aspergillus sp. lipase L (BLL), as well as two proteins expressed and purified for this study, B. cereus formamidase (FASE) and dihydropyrimidinase from S. meliloti CECT41 (DHP). The use of MPHIL is also proposed for any spectrophotometric measurement in the UV-VIS range, as well as for its integration as a concentration measurement platform in more advanced photonic lab on a chip systems. PMID:25537135

  9. Measurements of ice nuclei concentrations and compositions in the maritime tropics

    McMeeking, G. R.; Danielczok, A.; Bingemer, H.; Klein, H.; Hill, T. C.; Franc, G. D.; Martinez, M.; Venero, I.; Mayol-Bracero, O. L.; Ardon-Dryer, K.; Levin, Z.; Anderson, J.; Twohy, C. H.; Toohey, D. W.; DeMott, P. J.

    2011-12-01

    Tropical maritime cumulus clouds represent an important component of the global water cycle, but the relative roles of primary and secondary ice production in these clouds are poorly understood. Heterogeneous ice nuclei (IN) are responsible for ice initiation in towering tropical cumulus clouds, so information regarding their abundance, distribution, source compositions and dependence on cloud temperature is crucial to understanding the ice production processes. Here we present recent measurements of ice nuclei (IN) concentrations measured from ground-based and airborne (NSF/NCAR C-130) platforms during the Ice in Clouds-Tropical experiment, which took place in July 2011 over the Caribbean Sea near St. Croix in the US Virgin Islands. IN measurement techniques included airborne ambient and cloud particle residual measurements using a continuous flow diffusion chamber and off-line analysis of samples collected from the aircraft and two ground sites located on the island of Puerto Rico. Off-line measurements of IN concentrations included analysis by the Frankfurt Ice Nuclei Deposition FreezinG Experiment (FRIDGE) system and drop freezing via two methods of particles collected from filter samples. The measurement period included some periods with a strong Saharan dust influence that resulted in higher IN concentrations compared to clean maritime conditions. First analysis of IN physical, chemical and biological composition, and investigation of relationships between IN concentrations and total aerosol concentrations, composition and size are also presented.

  10. Extent of the last ice sheet in northern Scotland tested with cosmogenic 10Be exposure ages

    Phillips, W.M.; Hall, A.M.; Ballantyne, C.K.; Binnie, S.; Kubik, P.W.; Freeman, S.

    2008-01-01

    The extent of the last British-Irish Ice Sheet (BIIS) in northern Scotland is disputed. A restricted ice sheet model holds that at the global Last Glacial Maximum (LGM; ca. 23-19 ka) the BIIS terminated on land in northern Scotland, leaving Buchan, Caithness and the Orkney Islands ice-free. An alternative model implies that these three areas were ice-covered at the LGM, with the BIIS extending offshore onto the adjacent shelves. We test the two models using cosmogenic 10Be surface exposure dating of erratic boulders and glacially eroded bedrock from the three areas. Our results indicate that the last BIIS covered all of northern Scotland during the LGM, but that widespread deglaciation of Caithness and Orkney occurred prior to rapid warming at ca. 14.5 ka. Copyright ?? 2008 John Wiley & Sons, Ltd.