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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. 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)

  5. 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

  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. 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.

  8. 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.

  9. {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.

  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. 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

  16. 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)

  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. 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)

  4. 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,

  5. 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.

  6. 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.

  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. 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

  9. 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.

  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. 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

  14. 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.

  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. 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

  1. 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).

  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. 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

  9. 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.

  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. 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

  19. 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)

  20. 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

  1. 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

  2. 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

  3. 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

  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. 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.

  9. 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

  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. 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.

  4. 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.

  5. 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.

  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. 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}.

  8. 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

  9. 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

  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. 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.)

  8. 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...

  9. 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.)

  10. 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

  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. 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.

  16. 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.

  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. 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.

  1. 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...

  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. 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

  14. 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...

  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 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.

  7. 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.

  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. 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)

  12. 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)

  13. 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

  14. 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

  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. 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

  18. 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

  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. 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

  1. 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...

  2. 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.)

  3. 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...

  4. 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

  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. 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

  9. 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.

  10. 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)

  11. 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

  12. 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)

  13. 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...

  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. 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

  19. 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)

  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. 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

  2. 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.)

  3. 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

  4. 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

  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. 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)

  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. 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

  9. 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)

  10. 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.

  11. {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.

  12. 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

  13. 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.

  14. 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.

  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. 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...

  18. 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.)

  19. 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)

  20. 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

  1. 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.

  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. 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

  4. 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

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

    A. M. Smith

    2012-11-01

    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 degree 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 reconstructions as physically accurate as possible. Five 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, T63L31: a fine horizontal and vertical resolution and T63L47: a fine resolution horizontally and vertically with middle atmosphere. Comparison with observations suggests that a finer horizontal and vertical resolution might be beneficial, producing a reduced meridional gradient, although the spread between observations was much larger than between the five model runs. In terms of atmospheric mixing the differences became more distinguishable. All resolutions agreed that the main driver of deposition variability, observed in natural archives, is the input of 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 five model runs. The largest differences were found

  8. 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.

  9. Tectonic control on 10Be-derived erosion rates in the Garhwal Himalaya, India

    Scherler, Dirk; Bookhagen, Bodo; Strecker, Manfred R.

    2014-02-01

    Erosion in the Himalaya is responsible for one of the greatest mass redistributions on Earth and has fueled models of feedback loops between climate and tectonics. Although the general trends of erosion across the Himalaya are reasonably well known, the relative importance of factors controlling erosion is less well constrained. Here we present 25 10Be-derived catchment-averaged erosion rates from the Yamuna catchment in the Garhwal Himalaya, northern India. Tributary erosion rates range between ~0.1 and 0.5 mm yr-1 in the Lesser Himalaya and ~1 and 2 mm yr-1 in the High Himalaya, despite uniform hillslope angles. The erosion-rate data correlate with catchment-averaged values of 5 km radius relief, channel steepness indices, and specific stream power but to varying degrees of nonlinearity. Similar nonlinear relationships and coefficients of determination suggest that topographic steepness is the major control on the spatial variability of erosion and that twofold to threefold differences in annual runoff are of minor importance in this area. Instead, the spatial distribution of erosion in the study area is consistent with a tectonic model in which the rock uplift pattern is largely controlled by the shortening rate and the geometry of the Main Himalayan Thrust fault (MHT). Our data support a shallow dip of the MHT underneath the Lesser Himalaya, followed by a midcrustal ramp underneath the High Himalaya, as indicated by geophysical data. Finally, analysis of sample results from larger main stem rivers indicates significant variability of 10Be-derived erosion rates, possibly related to nonproportional sediment supply from different tributaries and incomplete mixing in main stem channels.

  10. 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

  11. 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.

  12. 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

  13. Determination of the minimum measurement time for estimating long-term mean radon concentration

    Radon measurements, as do any measurements, include errors in their readings. The relative values of such errors depend principally on the measurement methods used, the radon concentration to be measured and the duration of the measurements. Typical exposure times for radon surveys using passive detectors [nuclear track detectors, activated charcoal, electrostatic (E-perm), etc.)] may extend from a few days to months, whereas, in the case of screening methods utilising active radon monitors (AlphaGUARD, RAD7, EQF, etc.), the measurements may be completed quickly within a few hours to a few days. Thus, the latter may have relatively large error values, which affect the measurement accuracy significantly compared with the former measurements made over long time periods. The method presented in this paper examines the uncertainty of a short term radon measurement as an estimate of the long-term mean and suggests a minimum measurement time to achieve a given margin of uncertainty of that estimate. (authors)

  14. Concentration and composition measurement of sprays with a global rainbow technique

    Applications of the global rainbow technique to measure the concentration of a sprayed bi-component solution or the composition and the relative proportions of two sprays of different solutions at a local point are investigated. For a dual spray, the global rainbow signal is processed by optimally fitting the initial global rainbow signal with two global rainbow signals. For each composition, the value of the refractive index and size distribution is measured. In the case of spray mixing, the relative proportion of each composition can be retrieved from this information. The algorithms are validated by the processing of simulated global rainbows. Experimental rainbows of water–ethanol solutions with volume concentration from 0% to 100% and two sprays of water and ethanol are measured. The limitations of the global rainbow technique for concentration and composition measurements are discussed. (paper)

  15. The boron concentration measurement by the prompt gamma-ray analysis device at JRR-4

    In determining the dose for BNCT, it is important to measure the boron concentration in blood as well as the thermal neutron fluence. To attain an accurate measurement of the boron concentration in the whole blood at about 30 ppm, the Prompt Gamma-ray Analysis (PGA) is adopted to enable the measurement with a high degree of accuracy in short time, since the chemical analysis technique has some difficulties on it. In order to install the PGA device in a swimming pool type research reactor JRR-4, the super-mirror for obtaining the necessary neutron flux in the space over the pool surface was perpendicularly placed, because the reactor had no horizontal experiment tube for this kind of use. As the accurate measurement of the boron concentration in whole blood using PGA is enabled herewith, the first medical irradiation for BNCT at JRR-4 was carried out on October 25, 1999. (author)

  16. K-edge x-ray fluorescence analysis for actinide and heavy elements solution concentration measurements

    Advantages of using Co-57 as an exciter for K XRFA include: a compact design that requires no x-ray tubes; the exciter-detector assembly locates remote from support electronics; on-line, at-line, or off-line configurations for monitor/measurements; systems that can be run by semi-skilled technicians, once programmed; and operated via remote terminals with results sent to control rooms; heavy element concentrations that are measurable thru industrial pipes; independent of minor changes in solution matrix or source half life with concentration results reported in near-real-time; a dynamic range of measurable concentrations that is greater than 104; measurement times that are reasonable even at 1 gram/liter; and for nuclear safeguards, it provides the <0.5% accuracy required by DOE for the accountability of U, Pu, or both, once the system is calibrated

  17. Spatial concentration distribution analysis of cells in electrode-multilayered microchannel by dielectric property measurement.

    Yao, Jiafeng; Kodera, Tatsuya; Obara, Hiromichi; Sugawara, Michiko; Takei, Masahiro

    2015-07-01

    The spatial concentration distribution of cells in a microchannel is measured by combining the dielectric properties of cells with the specific structure of the electrode-multilayered microchannel. The dielectric properties of cells obtained with the impedance spectroscopy method includes the cell permittivity and dielectric relaxation, which corresponds to the cell concentration and structure. The electrode-multilayered microchannel is constructed by 5 cross-sections, and each cross-section contains 5 electrode-layers embedded with 16 micro electrodes. In the experiment, the dielectric properties of cell suspensions with different volume concentrations are measured with different electrode-combinations corresponding to different electric field distributions. The dielectric relaxations of different cell concentrations are compared and discussed with the Maxwell-Wagner dispersion theory, and the relaxation frequencies are analysed by a cell polarization model established based on the Hanai cell model. Moreover, a significant linear relationship with AC frequency dependency between relative permittivity and cell concentration was found, which provides a promising way to on-line estimate cell concentration in microchannel. Finally, cell distribution in 1 cross-section of the microchannel (X and Y directions) was measured with different electrode-combinations using the dielectric properties of cell suspensions, and cell concentration distribution along the microchannel (Z direction) was visualized at flowing state. The present cell spatial sensing study provides a new approach for 3 dimensional non-invasive online cell sensing for biological industry. PMID:26392831

  18. Measurements and predictors of on-road ultrafine particle concentrations and associated pollutants in Los Angeles

    Motor vehicles are the dominant source of oxides of nitrogen (NOx), particulate matter(PM), and certain air toxics (e.g., benzene, 1,3-butadiene) in urban areas. On roadways, motor vehicle-related pollutant concentrations are typically many times higher than ambient concentrations. Due to high air exchange rates typical of moving vehicles, this makes time spent in vehicles on roadways a major source of exposure. This paper presents on-road measurements for Los Angeles freeways and arterial roads taken from a zero-emission electric vehicle outfitted with real-time instruments. The objective was to characterize air pollutant concentrations on roadways and identify the factors associated with the highest concentrations. Our analysis demonstrated that on freeways, concentrations of ultrafine particles (UFPs), black carbon, nitric oxide, and PM-bound polycyclic aromatic hydrocarbons (PM-PAH) are generated primarily by diesel-powered vehicles, despite the relatively low fraction (∼6%) of diesel-powered vehicles on Los Angeles freeways. However, UFP concentrations on arterial roads appeared to be driven primarily by proximity to gasoline-powered vehicles undergoing hard accelerations. Concentrations were roughly one-third of those on freeways. By using a multiple regression model for the freeway measurements, we were able to explain 60-70% of the variability in concentrations of UFP, black carbon, nitric oxide, and PM-PAH using measures of diesel truck density and hour of day (as an indicator of wind speed). Freeway concentrations of these pollutants were also well correlated wth readily available annual average daily truck counts, potentially allowing improved population exposure estimates for epidemiology studies. Based on these roadway measurements and average driving time, it appears that 33-45% of total UFP exposure for Los Angeles residents occurs due to time spent traveling in vehicles. (author)

  19. Fundamental studies of three radioimmunoassay kits measuring prostatic acid phosphatase (PAP) concentrations

    Measurement of prostatic acid phosphatase (PAP) concentration is useful for the diagnosis and treatment of prostatic cancer. Fundamental studies of measurement of PAP concentration by radioimmunoassay were performed and values determined by three commercially available kits were compared, those are, PAP EIKEN RIA Kit (E kit), RIA Quant P.A.P. (M kit) and GammaDab PAP RIA Kit (C kit). Upper limits of normal PAP concentration were 3 ng/ml by E and M kits and 2 ng/ml by C kits, respectively. The reproducibility and the recovery studies of three kits were satisfactory. However, dilution curve of some patients was not strait. PAP concentration of 27 patients measured by three kits were correlated well to each other, but the discrepancy of values was noticed in high PAP concentrations. PAP concentration measured by RIA is more reliable than that by enzyme immunoassay. When keeping serum samples, the effect of time, temperature and freeze and thawing on PAP values was obvious. It is recommended that serum is separated at 40C as soon as possible after collecting blood and kept frozen until use. (author)

  20. Variability of {sup 10}Be and {delta}{sup 18}O in snow pits from Greenland and a surface traverse from Antarctica

    Berggren, A.-M. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Aldahan, A., E-mail: ala.aldahan@geo.uu.se [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates); Possnert, G. [Tandem Laboratory, Uppsala University, P.O. Box 529, 751 20 Uppsala (Sweden); Hansson, M. [Dept. of Physical Geography and Quaternary Geology, Stockholm University, 106 91 Stockholm (Sweden); Steen-Larsen, H.C. [Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej, 30,2100 Copenhagen (Denmark); Sturevik Storm, A. [Dept. of Earth Sciences, Uppsala University, Villav. 16, 752 36 Uppsala (Sweden); Moerth, C.-M. [Dept. of Geology and Geochemistry, Stockholm University, 106 91 Stockholm (Sweden); Murad, A. [Dept. of Geology, United Arab Emirates University, P.O. Box 17551 Al Ain (United Arab Emirates)

    2013-01-15

    To examine temporal variability of {sup 10}Be 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 {sup 10}Be in glacial ice was explored through collection of the upper {approx}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 {sup 10}Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the {delta}{sup 18}O data. The {sup 10}Be 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 {sup 10}Be and {delta}{sup 18}O, 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 {sup 10}Be concentrations in snow in Queen Maud Land, Antarctica.

  1. Dilution of 10Be in detrital quartz by earthquake-induced landslides: Implications for determining denudation rates and potential to provide insights into landslide sediment dynamics

    West, A. Joshua; Hetzel, Ralf; Li, Gen; Jin, Zhangdong; Zhang, Fei; Hilton, Robert G.; Densmore, Alexander L.

    2014-06-01

    The concentration of 10Be in detrital quartz (10Beqtz) from river sediments is now widely used to quantify catchment-wide denudation rates but may also be sensitive to inputs from bedrock landslides that deliver sediment with low 10Beqtz. Major landslide-triggering events can provide large amounts of low-concentration material to rivers in mountain catchments, but changes in river sediment 10Beqtz due to such events have not yet been measured directly. Here we examine the impact of widespread landslides triggered by the 2008 Wenchuan earthquake on 10Beqtz in sediment samples from the Min Jiang river basin, in Sichuan, China. Landslide deposit material associated with the Wenchuan earthquake has consistently lower 10Beqtz than in river sediment prior to the earthquake. River sediment 10Beqtz decreased significantly following the earthquake downstream of areas of high coseismic landslide occurrence (i.e., with greater than ∼0.3% of the upstream catchment area affected by landslides), because of input of the 10Be-depleted landslide material, but showed no systematic changes where landslide occurrence was low. Changes in river sediment 10Beqtz concentration were largest in small first-order catchments but were still significant in large river basins with areas of 104-105 km. Spatial and temporal variability in river sediment 10Beqtz has important implications for inferring representative denudation rates in tectonically active, landslide-dominated environments, even in large basins. Although the dilution of 10Beqtz in river sediment by landslide inputs may complicate interpretation of denudation rates, it also may provide a possible opportunity to track the transport of landslide sediment. The associated uncertainties are large, but in the Wenchuan case, calculations based on 10Be mixing proportions suggest that river sediment fluxes in the 2-3 years following the earthquake increased by a similar order of magnitude in the 0.25-1 mm and the sediment transfer, with

  2. Borrowing strengh in hierarchical Bayes: Posterior concentration of the Dirichlet base measure

    Nguyen, XuanLong

    2013-01-01

    This paper studies posterior concentration behavior of the base probability measure of a Dirichlet measure, given observations associated with the sampled Dirichlet processes, as the number of observations tends to infinity. The base measure itself is endowed with another Dirichlet prior, a construction known as the hierarchical Dirichlet processes (Teh et al. [J. Amer. Statist. Assoc. 101 (2006) 1566–1581]). Convergence rates are established in transportation distances (i.e., Wasserstein met...

  3. Applications of cosmogenic radio-isotopes, 10Be, 26Al and 36CI in the Earth Sciences using AMS at ANSTO

    Production of long-lived cosmogenic radionuclides (CRN) is dominated by cosmic ray interaction in the upper atmosphere. Through atmospheric transport and precipitation, they become distributed over the Earth's surface, and participate in various geochemical and geophysical global processes. An alternate production mode of CRNs is in the Earth's lithosphere, particularly in exposed rocks and surfaces. The production rate of these in-situ produced CRNs depends primarily on the reaction mode and type of target material. Although production is small - a few tens of atoms per gram per year - the built-up in concentration even after a few thousand years of exposure can be measured using the technique of Accelerator Mass Spectrometry. Concentrations of in situ nuclides in the near-surface zone allows a 'surface exposure history' to be estimated resulting in a measure of exposure ages and erosion rates. With a range in half-lives from 0.3-1.5 Ma, in-situ produced CRNs are ideally suited as geochronometers and tracers in Quaternary geomorphology related to paleoclimate change. This paper will briefly outline principles and techniques of 10Be, 26AI and 36CI in-situ methods and describe Some of the above projects related to the unique geomorphology of the Australian and Antarctic continents

  4. Remedial measures to reduce radon concentrations in a house with high radon levels

    Measures to reduce radon concentrations have been studied in an old house in which the radon decay-product concentration initially exceeded 0.3 Working Level (WL). Some of the measures were only partially successful. Installation of a concrete floor, designed to prevent ingress of radon in soil gas, reduced the radon decay-product concentration below 0.1 WL, but radon continued to enter the house through pores in an internal wall of primitive construction that descended to the foundations. Radon flow was driven by the small pressure difference between indoor air and soil gas. An under-floor suction system effected a satisfactory remedy and maintained the concentration of radon decay products below 0.03 WL

  5. Isovector and isoscalar dipole excitations in 9Be and 10Be studied with antisymmetrized molecular dynamics

    Kanada-En'yo, Yoshiko

    2016-02-01

    Isovector and isoscalar dipole excitations in 9Be and 10Be are investigated in the framework of antisymmetrized molecular dynamics, in which angular-momentum and parity projections are performed. In the present method, 1p-1h excitation modes built on the ground state and a large amplitude α -cluster mode are taken into account. The isovector giant dipole resonance (GDR) in E >20 MeV shows the two-peak structure, which is understood from the dipole excitation in the 2 α core part with the prolate deformation. Because of valence neutron modes against the 2 α core, low-energy E 1 resonances appear in E partner of the ground state having a 6He+α structure and has remarkable E 1 strength because of the coherent contribution of two valence neutrons. The isoscalar dipole strength for some low-energy resonances is significantly enhanced by the coupling with the α -cluster mode. For the E 1 strength of 9Be, the calculation overestimates the energy-weighted sum (EWS) in the low-energy (E <20 MeV) and GDR (20

  6. 26Al/10Be burial dating of Xujiayao-Houjiayao site in Nihewan Basin, northern China.

    Hua Tu

    Full Text Available The Xujiayao-Houjiayao site in Nihewan Basin is among the most important Paleolithic sites in China for having provided a rich collection of hominin and mammalian fossils and lithic artifacts. Based on biostratigraphical correlation and exploratory results from a variety of dating methods, the site has been widely accepted as early Upper Pleistocene in time. However, more recent paleomagnetic analyses assigned a much older age of ∼500 ka (thousand years. This paper reports the application of 26Al/10Be burial dating as an independent check. Two quartz samples from a lower cultural horizon give a weighted mean age of 0.24 ± 0.05 Ma (million years, 1σ. The site is thus younger than 340 ka at 95% confidence, which is at variance with the previous paleomagnetic results. On the other hand, our result suggests an age of older than 140 ka for the site's lower cultural deposits, which is consistent with recent post-infrared infrared stimulated luminescence (pIR-IRSL dating at 160-220 ka.

  7. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  8. Effect of whey protein concentrate on texture of fat-free desserts: sensory and instrumental measurements

    Márcia Cristina Teixeira Ribeiro Vidigal; Valéria Paula Rodrigues Minim; Afonso Mota Ramos; Elaine Berger Ceresino; Mayra Darliane Martins Silva Diniz; Geany Peruch Camilloto; Luis Antonio Minim

    2012-01-01

    It is important to understand how changes in the product formulation can modify its characteristics. Thus, the objective of this study was to investigate the effect of whey protein concentrate (WPC) on the texture of fat-free dairy desserts. The correlation between instrumental and sensory measurements was also investigated. Four formulations were prepared with different WPC concentrations (0, 1.5, 3.0, and 4.5 wt. (%)) and were evaluated using the texture profile analysis (TPA) and rheology....

  9. A portable biosensor system for bacterial concentration measurements in cow's raw milk

    Grossi, Marco; Lanzoni, Massimo; Pompei, Anna; Lazzarini, Roberto; Matteuzzi, Diego; Ricco, Bruno

    2011-01-01

    Bacterial detection is of primary importance in many fields, such as food and environmental monitoring. Measurements of bacterial concentration are traditionally carried out by means of the Standard Plate Count technique, a reliable method for microbial screening that, however, features long response time and is carried out by qualified personnel in microbiology laboratories. The impedance technique for bacterial concentration detection represents a method very competitive with Standard Plate...

  10. Development of a 10 Hz measurement system for atmospheric aerosol concentration

    The goal is to develop an aerosol charger based on a corona discharge for atmospheric concentration measurements (103-105 cm-3) within a response time of 100 ms. Two ion sources, point-to-hole and wire-to-slit have been characterized. The increase of the ion flow in the post-discharge by EHD ion confinement in both the discharge gap and the hole has been shown. At first, using an experimental survey driven in two mixing configurations, concentric and face-to-face, we have confirmed the aerosol diffusion charging law which depends on aerosol diameter and Ni.t product, with Ni, the ions concentration and t, the charging time. Thus, the originality of this charger relies on the very high heterogeneity of unipolar ion densities (Ni0 ≥109 cm-3) required to compensate the charging time of 50 ms. In these conditions, we have shown that aerosol diameter and the charging dynamic (which depends also on the diameter) control the aerosol trajectory. The chargers have, next, been compared in different operating conditions, mainly in terms of the maximal charging and the minimal losses. In the chosen charger (point-to-hole ion source and concentric mixing), the relations charge/mobility and losses according to diameter have been characterized. We have also shown the linearity of the charged particles current with the aerosol concentration which allows the current-concentration data inversion. The preliminary measurement system composed by the charger, the separator and the particle current measurements, satisfies the objectives of the study in terms of the concentration detection limit (103 cm-3) and the response time (100 ms). We have thus shown the feasibility of an atmospheric aerosol concentration measurement system at 10 Hz using a corona discharge charger provided that the separation power is improved. Furthermore, knowing that aerosol losses are negligible and the lower limit of the partial charging, the developed charger is adaptable with other application. (author)

  11. Measurement of FRET Efficiency and Ratio of Donor to Acceptor Concentration in Living Cells

    Chen, Huanmian; Puhl, Henry L.; Koushik, Srinagesh V.; Steven S Vogel; Ikeda, Stephen R.

    2006-01-01

    Measurement of fluorescence resonance energy transfer (FRET) efficiency and the relative concentration of donor and acceptor fluorophores in living cells using the three-filter cube approach requires the determination of two constants: 1), the ratio of sensitized acceptor emission to donor fluorescence quenching (G factor) and 2), the ratio of donor/acceptor fluorescence intensity for equimolar concentrations in the absence of FRET (k factor). We have developed a method to determine G and k t...

  12. Alternative method for concentration retrieval in differential optical absorption spectroscopy atmospheric gas pollutant measurements

    Videla, Fabián; Schinca, Daniel Carlos; Tocho, Jorge O.

    2003-01-01

    Differential optical absorption spectroscopy is a widely used technique for open-column atmospheric-gas pollution monitoring. The concentration retrieval is based on the fitting of the measured differential absorbance through the Lambert-Beer law. We present an alternative method for calculating the gas concentration on the basis of the proportionality between differential absorbance and differential absorption cross section of the gas under study. The method can be used on its own for single...

  13. Remote Three-Atom Information Concentration without Bell-State Measurement

    WU Zhen-Zhen; FANG Mao-Fa

    2006-01-01

    @@ We propose a scheme for information concentration of three remote two-level atoms in cavity QED. Our scheme does not involve the Bell-state measurement. During the interaction between atom and cavity, the cavity frequency is largely detuned from the atomic transition frequency, thus the scheme is insensitive to both the cavity decay and the thermal field. The idea can also be used to realize the remote information concentration of trapped ions.

  14. The measurement of thoron (220Rn) concentration in indoor air continuously using pylon model WLx

    The concentration of thoron (220Rn) in particular location can be higher than radon (220Rn), however, its presence is always neglected. This might be due to the difficulties in calibration and discrimination between radon and thoron. From biokinetic and dosimetric model, it has been known that the dominant contribution of thoron to the effective dose is in the lungs. UNSCEAR estimates the doses contribution of thoron and its progenies is between 5-10% of the annual dose received by the general public and the risk level is 4.4 times greater than radon and progenies. Therefore, it is necessary to study the thoron concentration in indoor air and workplaces. Radon-thoron concentration in indoor air can be determined by direct methods using Pylon Model WLx device and passive methods using Solid State Nuclear Track Detector (SSNTDs). In this research the measurement of thoron was carried out continuously using Pylon Model WLx equipment that is sensitive to radon for 24, 65, 72, 116 and 154 hours in different rooms. The measurement result showed that the mean value of thoron working level (WL) concentration obtained in room-1 was 2.53 ± 0.67 Bq/m3 with maximum and minimum of thoron concentrations were 3.37 and 2.22 Bq/m3 respectively. From the measurement in different locations, it was obtained that the largest and smallest average concentrations of thoron progenies were 0.83 ± 0.23 Bq/m3 and 0.29 ± 0.64 Bq/m3, while the maximum and minimum concentration values were 7.80 Bq/m3 and 0.01 Bq/m3 respectively. Pylon Model WLx device is not enables to be used for longer and large scale survey area concurrently, so the SSNTDs which is sensitive to the emission of alpha particles and can measure cumulative thoron concentrations is required. (author)

  15. Uranium and radon concentration measurements in drinking water samples from mineralized zone of Himachal Pradesh, India

    The uranium (238U) and radon (222Rn) concentrations were determined in drinking water samples collected from different sources such as handpumps, wells and tubewells of various depths from a wide range of 41 different locations of Hamirpur and Kangra districts Himachal Pradesh (HP) and adjoining areas of Jammu and Kashmir (JK), India. 238U and 222Rn concentration measurements in drinking water are important for determination of inhalation and ingestion dosimetry and health effects on the population. Laser Fluorimetry technique has been used for the measurement of Uranium concentration in drinking water samples. Radon measurements in water has been performed by using the appropriate bubbling technique with the Scintillation based radon monitor (SRM), which is free from humidity and has even been recommended by the Radiation Protection Advisory Division (RPAD) BARC, Mumbai. Radon concentration in these samples shows a wide range of variations for different sources and at different locations. The 238U and 222Rn concentrations in these samples has been observed to be in the range of 0.26 ± 0.1 to 29.5 ± 2.5 μgl-1 and 0.86 ± 0.12 to 7.62 ± 0.64 Bql-1 respectively. The measured values of radon concentration are within the recommended safe limits of 4 - 40 Bql-1 (UNSCEAR, 1993) and within the maximum contaminated level (MCL) of 11Bql-1 (USEPA, 1999). The observed uranium concentration values in drinking water samples have also been found to be within the safe limit of 30 μgl-1 as recommended by WHO, 2011 and even are quite less than threshold limit of 60 μgl-1 recommended by AERB, 2004. All measurements were performed in similar environmental conditions for minimal variations in meteorological parameters. (author)

  16. Concentrations of OH and HO2 radicals during NAMBLEX: measurements and steady state analysis

    S. C. Smith

    2006-01-01

    Full Text Available OH and HO2 concentrations were measured simultaneously at the Mace Head Atmospheric Research Station in the summer of 2002 during the NAMBLEX (North Atlantic Marine Boundary Layer EXperiment field campaign. OH was measured by laser-induced fluorescence employing the FAGE (Fluorescence Assay by Gas Expansion technique, with a mean daytime detection limit of 2.7×105 molecule cm−3 (5 min acquisition period; signal-to-noise ratio = 1. HO2 was detected as OH following its chemical conversion through addition of NO, with a mean detection limit of 4.4×106 molecule cm−3. The diurnal variation of OH was measured on 24 days, and that of HO2 on 17 days. The local solar noon OH concentrations ranged between (3–8×106 molecule cm−3, with a 24 h mean concentration of 9.1×105 molecule cm−3. The local solar noon HO2 concentrations were (0.9–2.1×108 molecule cm−3 (3.5–8.2 pptv, with a 24 h mean concentration of 4.2×107 molecule cm−3 (1.6 pptv. HO2 radicals in the range (2–3×107 molecule cm−3 were observed at night. During NAMBLEX, a comprehensive suite of supporting measurements enabled a detailed study of the behaviour of HOx radicals under primarily clean marine conditions. Steady state expressions are used to calculate OH and HO2 concentrations and to evaluate the effect of different free-radical sources and sinks. The diurnally averaged calculated to measured OH ratio was 1.04±0.36, but the ratio displays a distinct diurnal variation, being less than 1 during the early morning and late afternoon/evening, and greater than 1 in the middle of the day. For HO2 there was an overprediction, with the agreement between calculated and measured concentrations improved by including reaction with measured IO and BrO radicals and uptake to aerosols. Increasing the concentration of IO radicals included in the calculations to above that measured by a DOAS instrument with an absorption path located mainly over the ocean, reflecting the

  17. Concentrations of OH and HO2 radicals during NAMBLEX: measurements and steady state analysis

    G. P. Johnson

    2005-11-01

    Full Text Available OH and HO2 concentrations were measured simultaneously at the Mace Head Atmospheric Research Station in the summer of 2002 during the NAMBLEX (North Atlantic Marine Boundary Layer EXperiment field campaign. OH was measured by laser-induced fluorescence employing the FAGE (Fluorescence Assay by Gas Expansion technique, with a mean daytime detection limit of 2.7×105 molecule cm−3 (5 min acquisition period; signal-to-noise ratio = 1. HO2 was detected as OH following its chemical conversion through addition of NO, with a mean detection limit of 4.4×106 molecule cm−3. The diurnal variation of OH was measured on 24 days, and that of HO2 on 17 days. The local solar noon OH concentrations ranged between (3–8×106 molecule cm−3, with a 24 h mean concentration of 9.1×105 molecule cm−3. The local solar noon HO2 concentrations were (0.9–2.1×108 molecule cm−3 (3.5–8.2 pptv, with a 24 h mean concentration of 4.2×107 molecule cm−3. HO2 radicals in the range (2–3×107 molecule cm−3 were observed at night. During NAMBLEX, a comprehensive suite of supporting measurements enabled a detailed study of the behaviour of HOx radicals under primarily clean marine conditions. Case study periods highlight the typical radical levels observed under different conditions. Steady state expressions are used to calculate OH and HO2 concentrations and to evaluate the effect of different free-radical sources and sinks. The diurnally averaged calculated to measured OH ratio was 1.04±0.36, but the ratio displays a distinct diurnal variation, being less than 1 during the early morning and late afternoon/evening, and greater than 1 in the middle of the day. For HO2 there was an overprediction, with the agreement between calculated and measured concentrations improved by including reaction with measured IO and BrO radicals and uptake to aerosols. Increasing the concentration of IO radicals included in the calculations to above that measured by a DOAS

  18. Measurement of natural and 137Cs radioactivity concentrations at Izmit Bay (Marmara Sea), Turkey

    Öksüz, I.; Güray, R. T.; Özkan, N.; Yalçin, C.; Ergül, H. A.; Aksan, S.

    2016-03-01

    In order to determine the radioactivity level at Izmit Bay Marmara Sea, marine sediment samples were collected from five different locations. The radioactivity concentrations of naturally occurring 238U, 232Th and 40K isotopes and also that of an artificial isotope 137Cs were measured by using gamma-ray spectroscopy. Preliminary results show that the radioactivity concentrations of 238U and 232Th isotopes are lower than the average worldwide values while the radioactivity concentrations of the 40K are higher than the average worldwide value. A small amount of 137Cs contamination, which might be caused by the Chernobyl accident, was also detected.

  19. Measurements of indoor radon concentration in high natural radiation areas of Northern Italy

    We present results obtained with track-etch detectors on radon concentration indoor. The measurements have been performed in geologically interesting sites in North Italy such as Cervo Valley, the town of Angera and Valtellina, all of them being characterized by the presence of Uranium richores. The highest concentrations have been found in Cervo Valley, where a few villages are built on a massif of sienitea granite with particularly high Uranium concentration. Here many dwellings reach levels as high as 3000-6000 Bq/m3, while the average value is 525 Bq/m3. (author). 2 refs, 1 fig., 1 tab

  20. Using of Nuclear Track Detector C R-39 To Measure Depleted Uranium Concentration of Mother's Milk

    Biological samples of mother's milk were collected from Iraqi southern provinces (Basrah,Messan,Al-Muthana,Thikar) and Baghdad province to measure uranium concentration of the samples by using track technique of fission fragments as a result from uranium atom fission with thermal neutrons from neutrons source 241Am-Be with activity 16Ci and neutron flux of 5000n/cm2.s on using nuclear track detector C R-39.It was found that the high percentage of depleted uranium concentration on the samples from Muthana province, which accounted as 4.183ppm therefore the samples was taken from the provinces (Thikar,Basrah,Baghdad), which was accounted the depleted uranium concentration as following (1.243,2.172,2.875)ppm respectively, with appear a small concentration percentage in the Messan province which was accounted (0.230)ppm.Although, this concentration was been on the one baby food menu from mother's milk nutrition.In this research,the concentration of some essential trace elements in human breast milk, Ca, Na, K, Mg, Fe, Cu, Mn, Zn, Cr, Pb, Cd, Hg,was measured in the samples was taken from the above provinces by using atomic absorption technique and the result was indicated appear change in the concentration of the elements of the samples

  1. High frequency measurement of nitrate concentration in the Lower Mississippi River, USA

    Duan, Shuiwang; Powell, Rodney T.; Bianchi, Thomas S.

    2014-11-01

    Nutrient concentrations in the Mississippi River have increased dramatically since the 1950s, and high frequency measurements on nitrate concentration are required for accurate load estimations and examinations on nitrate transport and transformation processes. This three year record of high temporal resolution (every 2-3 h) data clearly illustrates the importance of high frequency sampling in improving load estimates and resolving variations in nitrate concentration with river flow and tributary inputs. Our results showed large short-term (days to weeks) variations in nitrate concentration but with no diurnal patterns. A repeatable and pronounced seasonal pattern of nitrate concentration was observed, and showed gradual increases from the lowest values in September (during base-flow), to the highest in June - which was followed by a rapid decrease. This seasonal pattern was only moderately linked with water discharge, and more controlled by nitrogen transformation/export from watershed as well as mixing patterns of the two primary tributaries (the upper Mississippi and the Ohio Rivers), which have distinctly different nitrate concentrations and flow patterns. Based on continuous in situ flow measurements, we estimated 554-886 × 106 kg of nitrate-N was exported from the Mississippi River system during years 2004-2006, which was help in monitoring short-term (days to weeks) variations in nutrient concentration patterns and thus improve the accuracy of nutrient flux estimates.

  2. Estimation of relative phycoerythrin concentrations from hyperspectral underwater radiance measurements--A statistical approach

    Taylor, Bettina B.; Taylor, Marc H.; Dinter, Tilman; Bracher, Astrid

    2013-06-01

    Phycobiliproteins are a family of water-soluble pigment proteins that play an important role as accessory or antenna pigments and absorb in the green part of the light spectrum poorly used by chlorophyll a. The phycoerythrins (PEs) are one of four types of phycobiliproteins that are generally distinguished based on their absorption properties. As PEs are water soluble, they are generally not captured with conventional pigment analysis. Here we present a statistical model based on in situ measurements of three transatlantic cruises which allows us to derive relative PE concentration from standardized hyperspectral underwater radiance measurements (Lu). The model relies on Empirical Orthogonal Function (EOF) analysis of Lu spectra and, subsequently, a Generalized Linear Model with measured PE concentrations as the response variable and EOF loadings as predictor variables. The method is used to predict relative PE concentrations throughout the water column and to calculate integrated PE estimates based on those profiles.

  3. Measurements of ammonia concentrations, fluxes and dry deposition velocities to a spruce forest 1991-1995

    Andersen, H.V.; Hovmand, M.F.; Hummelshøj, P.;

    1999-01-01

    The dry deposition velocities and fluxes of ammonia have been estimated from measurements of the vertical gradient of ammonia and micrometeorology above a spruce forest in western Jutland, Denmark. Measurements have been made in seven periods, each lasting about one week and covering all seasons......, i.e. an ammonia concentration below which the trees and/or the surface emit ammonia due to an equilibrium with the ammonia inside the needles or on the surface. Emission of ammonia was also observed at relatively high ammonia concentration levels (above 2 mu g NH3-N m(-3)), mainly during one...... measuring period characterized by easterly winds with dry conditions and high ammonia concentrations, and the emissions might relate to evaporation from ammonia saturated surfaces or emission from mineralization in the forest soil. In general, relatively high net deposition velocities were observed during...

  4. Particle concentrations and number size distributions in the planetary boundary layer derived from airship based measurements

    Tillmann, Ralf; Zhao, Defeng; Ehn, Mikael; Hofzumahaus, Andreas; Holland, Frank; Rohrer, Franz; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    Atmospheric particles play a key role for regional and global climate due to their direct and indirect radiative forcing effects. The concentration and size of the particles are important variables to these effects. Within the continental planetary boundary layer (PBL) the particle number size distribution is influenced by meteorological parameters, local sinks and sources resulting in variable spatial distributions. However, measurements of particle number size distributions over a broad vertical range of the PBL are rare. The airship ZEPPELIN NT is an ideal platform to measure atmospheric aerosols on a regional scale within an altitude range up to 1000 m. For campaigns in the Netherlands, Northern Italy and South Finland in 2012 and 2013 the airship was deployed with a wide range of instruments, including measurements of different trace gases, short lived radicals, solar radiation, aerosols and meteorological parameters. Flights were carried out at different times of the day to investigate the influence of the diurnal evolution of the PBL on atmospheric trace gases and aerosols. During night and early morning hours the concentration and size distribution of atmospheric particles were found to be strongly influenced by the layered structure of the PBL, i.e. the nocturnal boundary layer and the residual layer. Within the residual layer particle concentrations stay relatively constant as this layer is decoupled from ground sources. The particles persist in the accumulation mode as expected for an aged aerosol. In the nocturnal boundary layer particle concentrations and size are more dynamic with higher concentrations than in the residual layer. A few hours after sunrise, the layered structure of the PBL intermixes. During daytime the PBL is well mixed and a negative concentration gradient with increasing height is observed. Several height profiles at different times of the day and at different locations in Europe were measured. The aerosol measurements will be

  5. Windows pollution problems of the dust concentration measurement based on scattering method

    The windows are separated the measurement system from the dust space in the light Scattering dust concentration measurement system. The windows are polluted unavoidably by the dust and the measurement error is produced. Based on the Mie Scattering theory, the measurement error is researched in this paper. The numerical simulation results show that the measurement error is related to the particles diameter distribution and the refractive index, but is independent of the particles average diameter. A novel photoelectricity sensor is developed in this paper in order to solve the measurement error by the windows pollution. The calculated method is brought out which can amend the measurement errors by the windows pollution and improve the measurement accuracy.

  6. Global scale analysis of the stream power law parameters based on worldwide 10Be denudation rates

    Harel, Marie-Alice; Mudd, Simon; Attal, Mikael

    2015-04-01

    The stream power law, expressed as E = KAmSn where E is erosion rate [LT-1], K is erodibility [T-1L(1-2m)], A is drainage area [L2], S is channel gradient [L/L] and m and n are constants, is the most widely used model for bedrock channel incision. Despite its simplicity and limitations, the model has proved useful for a large number of applications such as topographic evolution, knickpoint migration, palaeotopography reconstruction, and the determination of uplift patterns and rates. However, the unknown parameters K, m and n are often fixed arbitrarily or are based on assumptions about the physics of the erosion processes that are not always valid, which considerably alters the use and interpretation of the model. In this study, we compile published 10Be basin-wide erosion rates (n = 1335) in order to assess the m/n ratio (or concavity index), the slope exponent n and erodibility coefficient K using the integral method of channel profile analysis. These three parameters are calculated for 66 areas and allow for a global scale analysis in terms of climatic, tectonic and environmental settings. Our results suggest that (i) many sites are too noisy or do not have enough data to predict n and K with a satisfying level of confidence; (ii) the slope exponent is predominantly greater than one, meaning that the relationship between erosion rate and the channel gradient is non-linear, supporting the idea that incision is a threshold controlled process. Furthermore, a multi-regression analysis and the calculation of n and K using a reference concavity index m/n = 0.45 demonstrate that (iii) many intuitive or previously demonstrated local-scale trends, such as the correlation between erosion rate and climate, do not appear at a global scale.

  7. Underwater Optical Fiber Fluorescent System for Measuring Chlorophyll-a Concentration

    2001-01-01

    Using optical fiber fluorescent technology,a new method for measuring alga concentration in water is presented. The system can realize on-line measurement for alga concentration using He-Ne laser as the light source. It can also effectively detect weak signals. The system with a passive sensor head has such advantages as simple structure, high sensitivity and high accuracy. It has been demonstrated that this system can be used to monitor water quality and can also be used to survey some matter.

  8. Measurement of Sr/sup 90/ concentration in environmental media at Chasma site

    A study for the measurement of Sr/sup 90/ concentration in environmental media such as vegetable, meat, milk and soil samples collected from CHASNUPP site was carried out during the year 2000. The measurement procedure includes the radiochemical separation of Y/sup 90/ by solvent extraction followed by counting on low-level liquid scintillation counter. Average concentration of Sr/sup 90/ in samples varies from 0.04 to 2.5 Bq/ kg or Bq/ liter. This level is comparable with the local and regional radioactivity levels reported on strontium. (author)

  9. Isoprene concentrations over Russia: ground-based measurements and chemistry-transport modeling

    Berezina, Elena; Konovalov, Igor; Berezin, Evgeny; Skorokhod, Andrey; Elansky, Nikolay; Belikov, Igor

    2016-04-01

    Near-surface isoprene concentration was measured over Russia using the proton mass spectrometry method (PTR-MS) in TROICA (TRanscontinental Observations Into the Chemistry of the Atmosphere) experiments along the Trans-Siberian railway from 21.06.08 to 04.08.08 (TROICA-12) and from 08.10.09 to 23.10.09 (TROICA-13). The highest isoprene concentration is observed in the Far East (up to 3 ppb) due to the emissions from the major isoprene source - deciduous forests. The TROICA measurements were compared to the corresponding simulations performed with the CHIMERE chemistry transport model (CTM) using the MEGAN biogenic emission inventory. Simulated and measured isoprene concentrations are highly correlated (r = 0.8), but the simulated isoprene concentration is about 4-6 times higher than the measured one. The selection of daytime and background (from isoprene/benzene ratios) isoprene concentrations don't significantly increase the experimental values; moreover, even the isoprene concentration corrected for atmospheric photochemical losses (that is, the near-source concentration) is found to be 1.5 times lower than the simulated data. Therefore, the systematic discrepancy between the measurements and simulations could not be unambiguously attributed to the representativity error. The weak exponential dependence of summer isoprene concentration on temperature both for the model (R2 = 0.3) and for the experimental data (R2 = 0.4) is observed. However, a much stronger linear correlation (r ~ 0.9) is found between the isoprene concentration and temperature in Russian regions separated according to the type of vegetation. The differences between the simulated and experimental dependences of isoprene concentration on temperature are not statistically significant. The above results prompt the conclusion that the parameterization of isoprene emissions in the CHIMERE CTM is qualitatively adequate, but the isoprene emission factors applicable for Russian forest are likely

  10. Field inter-comparison of three systems for NH3 concentration and flux measurements

    Voglmeier, Karl; Ammann, Christof; Neftel, Albrecht; Häni, Christoph; Richter, Undine; Brümmer, Christian

    2016-04-01

    Ambient air ammonia analyzer systems that are not only used for concentration but also for flux measurements have to meet special requirements. They either have to provide a fast response detection (c. 1 sec) for the application of the eddy covariance technique (EC) or they have to resolve relatively small horizontal or vertical concentration gradients. The Posieux intercomparison experiment in fall 2015 was designed to compare three advanced and different approaches to determine concentration and fluxes of NH3 of a grazed pasture during several weeks. The methods involved: [1] a two channel reactive N converter measuring in parallel the sum of oxidized N species with the exception of N2O and the sum of the total reactive N species. The difference of the two channels corresponds to the sum of reduced reactive N species; [2] a QC laser analyzer with a special designed inlet system that minimize wall effects and separates particles from the gas sampling stream; [3] two MiniDOAS instruments for line integrated concentration without any inlet system. The experimental setup and the environmental conditions resulted in a high temporal and spatial dynamic of NH3 concentrations and fluxes. Systems [1] and [2] are designed to perform flux measurements by the Eddy Covariance technique, whereas the DOAS technique has a temporal resolution of 1 min. Fluxes are calculated from the horizontal concentration increase across an emitting surface with back lagrangian stochastic trajectory dispersion model. We present a comparison of the measured concentrations and fluxes and discuss the advantages and limitations of the three chosen systems.

  11. Measurement of low concentration and nano-quantity hydrogen sulfide in sera using unfunctionalized carbon nanotubes

    Hydrogen sulfide (H2S) is produced in small amounts by certain cells in the mammalian body and has a number of biological functions. H2S gas naturally produced by the body is not simply a toxic gas; it could be a vascular dilator and play a physiological role in regulating cardiovascular functions. In order to know the effects of H2S, it is necessary to accurately know its concentrations in the body. Conventional measurement methods have their limitations concerning the small amount and low concentration of H2S in the body. A new paradigm of using carbon nanotubes in H2S measurement expresses its potential. However, the influence of proteins in the mammalian body must be studied in the measurement of H2S by carbon nanotubes. In this paper, we demonstrate a successful measurement of low concentration (20 µM) and nano-quantity (0.5 µg) H2S in the serum by using carbon nanotubes and further with the fluorescence of confocal laser scanning microscopy and the luminescence of Raman microscopy. Statistical analysis of the experimental data shows that the relationship between concentrations and intensities is linear, which thus makes the carbon nanotube sensor highly promising for the measurement of H2S in sera

  12. Helium-3 and boron-10 concentration and depth measurements in alloys and semiconductors using NDP

    Ünlü, Kenan; Saglam, Mehmet; Wehring, Bernard W.

    1999-02-01

    Neutron Depth Profiling (NDP) is a nondestructive near surface technique that is used to measure concentration versus absolute depth of several isotopes of light mass elements in various substrates. NDP is based on absorption reaction of thermal neutrons with the isotope of interest. Charged particles and recoil atoms are generated in the reaction. The depth profiles are determined by measuring the residual energy of the charged particles or the recoil atoms. The NDP technique has became an increasingly important method to measure depth profiles of 3He and 10B in alloys and semiconductor materials. A permanent NDP facility has been installed on the tangential beam port of the University of Texas (UT) TRIGA Mark-II research reactor. One of the standard applications of the UT-NDP facility involves the determination of boron profiles of borophosphosilicate glass (BPSG) samples. NDP is also being used in combination with electron microscopy measurements to determine radiation damage and microstructural changes in stainless steel samples. This is done to study the long-term effects of high-dose alpha irradiation for weapons grade plutonium encapsulation. Measurements of implanted boron-10 concentration and depth profiles of semiconductor materials in order to calibrate commercial implanters is another application at the UT-NDP facility. The concentration and depth profiles measured with NDP and SIMS are compared with reported data given by various vendors or different implanters in order to verify implant quality of semiconductor wafers. The results of the measurements and other possible applications of NDP are presented.

  13. Peak tailing correction in measurement of 222Rn/220Rn activity concentration with α spectrum method

    α spectrum method is one of the most important methods in measurement of 222Rn/220Rn concentration in environment. However, the peak tailing from high energy particles is an obstacle for accurate measurement. To improve the accuracy of measurement, study on the mechanism and effect of the tailing were carried out, and calibrating experiments on peak tailing correction factors were also realized using ERS-2 monitor. The peak tailing correction factors and calibration factors of 222Rn and 220Rn were measured by experiment and their accuracy were also tested. It is suggested that during calibrating α spectrum monitor of 222Rn/220Rn activity concentration, the peak tailing correction and calibration factors should be recalibrated if necessary. (authors)

  14. The CREp program, a fully parameterizable program to compute exposure ages (3He, 10Be)

    Martin, L.; Blard, P. H.; Lave, J.; Delunel, R.; Balco, G.

    2015-12-01

    Over the last decades, cosmogenic exposure dating permitted major advances in Earth surface sciences, and particularly in paleoclimatology. Yet, exposure age calculation is a dense procedure. It requires numerous choices of parameterization and the use of an appropriate production rate. Nowadays, Earth surface scientists may either calculate exposure ages on their own or use the available programs. However, these programs do not offer the possibility to include all the most recent advances in Cosmic Ray Exposure (CRE) dating. Notably, they do not propose the most recent production rate datasets and they only offer few possibilities to test the impact of the atmosphere model and the geomagnetic model on the computed ages. We present the CREp program, a Matlab © code that computes CRE ages for 3He and 10Be over the last 2 million years. The CREp program includes the scaling models of Lal-Stone in the "Lal modified" version (Balco et al., 2008; Lal, 1991; Stone, 2000) and the LSD model (Lifton et al., 2014). For any of these models, CREP allows choosing between the ERA-40 atmosphere model (Uppala et al., 2005) and the standard atmosphere (National Oceanic and Atmospheric Administration, 1976). Regarding the geomagnetic database, users can opt for one of the three proposed datasets: Muscheler et al. 2005, GLOPIS-75 (Laj et al. 2004) and the geomagnetic framework proposed in the LSD model (Lifton et al., 2014). They may also import their own geomagnetic database. Importantly, the reference production rate can be chosen among a large variety of possibilities. We made an effort to propose a wide and homogenous calibration database in order to promote the use of local calibration rates: CREp includes all the calibration data published until July 2015 and will be able to access an updated online database including all the newly published production rates. This is crucial for improving the ages accuracy. Users may also choose a global production rate or use their own data

  15. Global analysis of the stream power law parameters based on worldwide 10Be denudation rates

    Harel, M.-A.; Mudd, S. M.; Attal, M.

    2016-09-01

    The stream power law, expressed as E = KAmSn - where E is erosion rate [LT - 1], K is an erodibility coefficient [T - 1L (1 - 2m)], A is drainage area [L 2], S is channel gradient [L/L], and m and n are constants - is the most widely used model for bedrock channel incision. Despite its simplicity and limitations, the model has proved useful for topographic evolution, knickpoint migration, palaeotopography reconstruction, and the determination of rock uplift patterns and rates. However, the unknown parameters K, m, and n are often fixed arbitrarily or are based on assumptions about the physics of the erosion processes that are not always valid, which considerably limits the use and interpretation of the model. In this study, we compile a unique global data set of published basin-averaged erosion rates that use detrital cosmogenic 10Be. These data (N = 1457) enable values for fundamental river properties to be empirically constrained, often for the first time, such as the concavity of the river profile (m/n ratio or concavity index), the link between channel slope and erosion rate (slope exponent n), and substrate erodibility (K). These three parameters are calculated for 59 geographic areas using the integral method of channel profile analysis and allow for a global scale analysis in terms of climatic, tectonic, and environmental settings. In order to compare multiple sites, we also normalize n and K using a reference concavity index m/n = 0.5. A multiple regression analysis demonstrates that intuitive or previously demonstrated local-scale trends, such as the correlation between K and precipitation rates, do not appear at a global scale. Our results suggest that the slope exponent is generally > 1, meaning that the relationship between erosion rate and the channel gradient is nonlinear and thus support the hypothesis that incision is a threshold controlled process. This result questions the validity of many regional interpretations of climate and/or tectonics where

  16. GUM approach to uncertainty estimations for online 220Rn concentration measurements using Lucas scintillation cell

    It is now widely recognized that, when all of the known or suspected components of errors have been evaluated and corrected, there still remains an uncertainty, that is, a doubt about how well the result of the measurement represents the value of the quantity being measured. Evaluation of measurement data - Guide to the expression of Uncertainty in Measurement (GUM) is a guidance document, the purpose of which is to promote full information on how uncertainty statements are arrived at and to provide a basis for the international comparison of measurement results. In this paper, uncertainty estimations following GUM guidelines have been made for the measured values of online thoron concentrations using Lucas scintillation cell to prove that the correction for disequilibrium between 220Rn and 216Po is significant in online 220Rn measurements

  17. Full-field dye concentration measurement within saturated/unsaturated thin slabs of porous media

    This paper presents a full-field dye concentration measurement technique that extends our experimental capabilities to the measurement of transient dye concentration fields within steady state flow fields under unsaturated or saturated conditions. Simple light absorption theory provides a basis for translating images into high resolution dye concentration fields. A series of dye pulse experiments that demonstrate the combined use of the full-field saturation and dye concentration techniques was conducted at four different degrees of saturation. Each of these experimental sequences was evaluated with respect to mass balance, the results being within 5% of the known dye mass input. An image windowing technique allowed us to see increased dispersion due to decreasing moisture content, tailing of concentration at the rear of the dye pulse and slight velocity changes of the dispersive front due to changes in moisture content. The exceptional resolution of dye concentration in space and time provided by this laboratory technique allows systematic experimentation for examining basic processes affecting solute transport within saturated/unsaturated porous media. Future challenges for this work will be to use these techniques to analyze more complex systems involving heterogeneities, scaling laws, and detailed investigations of the relationship between transverse and longitudinal dispersion in unsaturated media

  18. Measuring and modeling suspended sediment concentration profiles in the surf zone

    2012-01-01

    Time-averaged suspended sediment concentration profiles across the surf zone were measured in a large-scale three-dimensional movable bed laboratory facility (LSTF:Large-scale Sediment Transport Facility). Sediment suspension under two different types of breaking waves, spilling and plunging breakers, was investigated. The magnitudes and shapes of the concentration profiles varied substantially at different locations across the surf zone, reflecting the different intensities of breaking-induced turbulence. Sediment sus- pension at the energetic plunging breaker-line was much more active, resulting in nearly homogeneous concentration profiles throughout most of the water column, as compared to the reminder of the surf zone and at the spilling breaker-line. Four suspended sediment concentration models were examined based on the LSTF data, including the mixing turbulence length approach, segment eddy viscosity model, breaking-induced wave-energy dissipation approach, and a combined breaking and turbulence length model developed by this study. Neglecting the breaking-induced turbulence and subsequent sediment mixing, suspended sediment concentration models failed to predict the across-shore variations of the sediment suspension, especially at the plunging breaker-line. Wave-energy dissipation rate provided an accurate method for estimating the intensity of turbulence generated by wave breaking. By incorporating the breaking-induced turbulence, the combined breaking and turbulence length model reproduced the across-shore variation of sediment suspension in the surf zone. The combined model reproduced the measured time-averaged suspended sediment concentration profiles reasonably well across the surf zone.

  19. Comparison of VIDAS and Radioimmunoassay Methods for Measurement of Cortisol Concentration in Bovine Serum

    Daniela Proverbio

    2013-01-01

    Full Text Available Radioimmunoassay (RIA is the “gold standard” method for evaluation of serum cortisol concentration. The VIDAS cortisol test is an enzyme-linked fluorescent assay designed for the MiniVidas system. The aim of this study was to compare the VIDAS method with RIA for measurement of bovine serum cortisol concentration. Cortisol concentrations were evaluated in 40 cows using both VIDAS and RIA methods, the latter as the reference method. A paired Student’s -test, Pearson’s correlation analysis, Bland-Altman plot, and Deming regression analysis were used to compare the two methods. There was no statistically significant difference between mean serum cortisol concentrations measured by VIDAS or RIA methods (. Both methods were able to detect significant differences in mean low and high cortisol concentrations ( RIA and VIDAS. The correlation coefficient was low, but a Bland-Altman plot and Deming regression analysis show neither constant nor proportional error. The VIDAS method produced slightly higher values than RIA, but the difference was small and in no case did the mean value move the normal range. Results suggest that VIDAS method is suitable for the determination of bovine serum cortisol concentration in studies of large numbers of animals.

  20. Odour Pollution Measurement from Refuse Derive Fuel Operations Using Odour Concentration Meter (OCM XP-329

    Zaini Sakawi

    2013-04-01

    Full Text Available Odour perception is subjective and difficult to be accurately measured between individuals. Hence many studies on odour issues are more commonly pertain to its intensity, concentration, types, standards, measurement methods, law and impacts on physical and human environments. Nevertheless, odour analysis can be conducted empirically or based on human sensorial. Among major sources of odour pollution are animal rearing, oil palm and rubber mills, dumpsites, industries and sewage treatments. This study attempted to measure odour pollution generated by Refuse Derived Fuel (RDF operation. The analysis was conducted at different times of day (morning, evening and night and weather conditions (normal days and after rains. 10 sampling stations were selected for observations using the Odour Concentration Meter Siri XP-329 III.The results indicated that there existed different level of odour concentrations on normal days and after rains due to the influence of meteorological environment. Distance factors also influenced the odour concentrations, whereby gradually, the stations further from RDF operation recorded higher odour concentrations

  1. Development of a fluorescent method for simultaneous measurement of glucose concentrations in interstitial fluid and blood

    Continuous blood glucose monitoring is of great clinical significance to patients with diabetes. One of the effective methods to monitor blood glucose is to measure glucose concentrations of interstitial fluid (ISF). However, a time-delay problem exists between ISF and blood glucose concentrations, which results in difficulty in indicating real-time blood glucose concentrations. Therefore, we developed a fluorescent method to verify the accuracy and reliability of simultaneous ISF and blood glucose measurement, especially incorporating it into research on the delay relationship between blood and ISF glucose changes. This method is based on a competitive reaction among borate polymer, alizarin and glucose. When glucose molecules combine with borate polymers in alizarin–borate polymer competitively, changes in fluorescence intensity demonstrate changes in glucose concentrations. By applying the measured results to the blood and ISF glucose delay relationship, we were able to calculate the time delay as an average of 2.16 ± 2.05 min for ISF glucose changes with reference to blood glucose concentrations. (paper)

  2. Radon activity concentration and gamma dose rate measurements in Hungarian dwellings

    The goal of this study was to estimate the annual effective dose of population based on the measured indoor radon activity concentration and gamma dose rate. This investigation can be considered as a pilot study for radon mapping and legislation preparation. Bricks represent the most popular building material in Hungary. Detached houses without cellar constitute the majority of dwellings examined. The average and range of radon activity concentration and ambient dose equivalent rate for the given period were 136.8 (27.8 - 793.9) Bq.m-3 and 142.2 (70.2 - 284.2) nSv.h-1, respectively. Thirty-one radon measurements were below the detection limit of . 27.8 Bq/m3. The results of radon activity concentration and ambient gamma dose rate measurements are presented in a tabular form. The distribution of indoor radon activity concentration is log-normal and is consistent with published data. The percentages of dwellings exceeding the EU reference levels (200, 400 and 600 Bq.m-3) are also tabulated. The distribution of gamma dose rate is basically normal. The annual effective dose equivalent due to the indoor radon concentration and gamma dose rate estimated by using the dose conversion and occupancy factors of ICRP Publication No 65 and UNSCEAR Report of 2000 were 3.06 and 0.57 mSv/year, respectively. (P.A.)

  3. Odour Pollution Measurement from Refuse Derive Fuel Operations Using Odour Concentration Meter (OCM) XP-329

    Zaini Sakawi; Lukman Ismail; Mohd Rozaimi Ariffin; School of Social, Development, Environmental Studies, Universiti Kebangsaan Malaysia

    2013-01-01

    Odour perception is subjective and difficult to be accurately measured between individuals. Hence many studies on odour issues are more commonly pertain to its intensity, concentration, types, standards, measurement methods, law and impacts on physical and human environments. Nevertheless, odour analysis can be conducted empirically or based on human sensorial. Among major sources of odour pollution are animal rearing, oil palm and rubber mills, dumpsites, industries and sewage treatments. Th...

  4. MEASUREMENT OF VITAMIN B12 CONCENTRATION: A REVIEW ON AVAILABLE METHODS

    Karmi O et al

    2011-01-01

    Vitamin B12 is a water-soluble vitamin. It is one of the eight vitamins of vitamin B complex, needed for blood and cell maturation. It helps maintain healthy nerve cells and red blood cells, and it is needed in DNA replication. Its deficiency may cause megaloblastic anemia (amidst others health issues). For these and many similar reasons, it sometimes becomes necessary to measure its concentration. This article has carefully reviewed the different methods used for measuring vitamin B12 concen...

  5. An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids

    Keene, William C; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold; Castro, Mark; Farmer, J. Carl; Galloway, James N.; Hoffmann, Michael R.; Li, Shao-Meng; Maben, John R.; Munger, J. William; Norton, Richard B.; Pszenny, Alexander A. P.; Puxbaum, Hans

    1989-01-01

    During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH_3COOH) were intercompared in central Virginia. HCOOH and CH_3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH impregnated quartz filters, K_2CO_3 and Na_2CO_3 impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters usi...

  6. Calculation of response coefficient for low-level liquid radioactivity concentration measurement device

    Background: The on-line low-level liquid radioactivity concentration measurement device is designed for monitoring the radioactivity level of nuclear power plant waste water. The relation between the radioactivity concentration of 137Cs in the liquid of pipeline and the counting rate of measurement device, i.e. the response coefficient is must be known. It is generally given by experimental calibration. But the calibration is difficult for on-line measurement. Purpose: This paper attempts to study the response coefficient of on-line measurement device by calculation. Methods: The response coefficient is calculated by Monte Carlo method and in which gamma-ray transport processes in detection device are simulated. The response counts in Nal detector derived from 137Cs in the liquid are calculated. Results: The response coefficient of off-line measuring device is calculated firstly. The result is in good agreement with the experimental calibration and the difference is small than 3%. It is indicated that the method is correct and the calculation model is reasonable. Then, the response coefficient of on-line measuring devices is calculated according to the on-line measurement device design and the structure of Nal detector. The minimum detectable concentration is given according to the response coefficient and the background count rate. Conclusions: The response coefficient of on-line measurement device is 1.249×10-4 s-1·Bq-1·m3 and the minimum detectable concentration can reach (4-5)×103 Bq·m-3 when the thickness of lead shield is 80 mm. (authors)

  7. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    J. C. Gong; Zhu, T.; M. Hu; L. W. Zhang; Cheng, H.; L. Zhang; Tong, J; Zhang, J.

    2010-01-01

    Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein) in a central Beijing site in the summer and early fall of 2008 (from June to October). Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's...

  8. Measurement of competitive balance in professional team sports using the Normalized Concentration Ratio

    Vasileios Manasis; Vassiliki Avgerinou; Ioannis Ntzoufras; J. James Reade

    2011-01-01

    Competitive balance is an important concept in professional team sports; its measurement is, therefore, a critical issue. One of the most widely used indices, which was introduced for the estimation of seasonal competitive balance is the Concentration Ratio, which is a relatively simple index and measures the extent to which a league is dominated by a particular number of teams. However, it is shown that both the total number of league teams and the number of dominant teams under examination ...

  9. 10Be and δ2H in polar ice cores as a probe of the solar variability's influence on climate

    By using the technique of accelerator mass spectrometry, it is now possible to measure detailed profiles of cosmogenic (cosmic ray produced) 10Be in polar ice cores. Recent work has demonstrated that these profiles contain information on solar activity, via its influence on the intensity of galactic cosmic rays arriving in the Earth's atmosphere. It has been known for some time that, as a result of temperature-dependent fractionation effects, the stable isotope profiles δ2O and δ2H in polar ice cores contain palaeoclimate information. Thus by comparing the 10Be and stable isotope profiles in the same ice core, one can test the influence of solar variability on climate, and this independent of possible uncertainties in the absolute chronology of the records. We present here the results of such a comparison for two Antarctic ice cores; one from the South Pole, covering the past ca. 1000 years, and one from Dome C, covering the past ca. 3000 years. (author)

  10. PGNAA system preliminary design and measurement of In-Hospital Neutron Irradiator for boron concentration measurement.

    Zhang, Zizhu; Chong, Yizheng; Chen, Xinru; Jin, Congjun; Yang, Lijun; Liu, Tong

    2015-12-01

    A prompt gamma neutron activation analysis (PGNAA) system has been recently developed at the 30-kW research reactor In-Hospital Neutron Irradiator (IHNI) in Beijing. Neutrons from the specially designed thermal neutron beam were used. The thermal flux of this beam is 3.08×10(6) cm(-2) s(-1) at a full reactor power of 30 kW. The PGNAA system consists of an n-type high-purity germanium (HPGe) detector of 40% efficiency, a digital spectrometer, and a shielding part. For both the detector shielding part and the neutron beam shielding part, the inner layer is composed of (6)Li2CO3 powder and the outer layer lead. The boron-10 sensitivity of the PGNAA system is approximately 2.5 cps/ppm. Two calibration curves were produced for the 1-10 ppm and 10-50 ppm samples. The measurement results of the control samples were in accordance with the inductively coupled plasma atomic emission spectroscopy (ICP-AES) results. PMID:26242556

  11. Measuring oxidative stress: the confounding effect of lipid concentration in measures of lipid peroxidation.

    Pérez-Rodríguez, Lorenzo; Romero-Haro, Ana A; Sternalski, Audrey; Muriel, Jaime; Mougeot, Francois; Gil, Diego; Alonso-Alvarez, Carlos

    2015-01-01

    Lipid peroxidation products are widely used as markers of oxidative damage in the organism. To properly interpret the information provided by these markers, it is necessary to know potential sources of bias and control confounding factors. Here, we investigated the relationship between two indicators of lipid mobilization (circulating levels of triglycerides and cholesterol) and two common markers of oxidative damage (plasma levels of malondialdehyde and hydroperoxides; the latter estimated from the d-ROMs assay kit). The following five avian species were studied: red-legged partridge (Alectoris rufa), zebra finch (Taeniopygia guttata), spotless starling (Sturnus unicolor), marsh harrier (Circus aeroginosus), and Montagu's harrier (Circus pygargus). In all cases, plasma triglyceride levels positively and significantly correlated with lipid peroxidation markers, explaining between 8% and 34% of their variability. Plasma cholesterol, in contrast, showed a significant positive relationship only among spotless starling nestlings and a marginally significant association in zebra finches. These results indicate that lipid peroxidation marker levels covary with circulating lipid levels. We discuss the potential causes and implications of this covariation and recommend that future studies that measure oxidative damage using lipid peroxidation markers report both raw and relative levels (i.e., corrected for circulating triglycerides). Whether the observed pattern also holds for other tissues and in other taxa would deserve further research. PMID:25860832

  12. Noninvasive Measurement of Fecal Progesterone Concentration in Toy Poodles by Time Resolved Fluoroimmunoassay (TR-FIA

    Satoshi Sugimura

    2008-01-01

    Full Text Available Progesterone is an important reproductive hormone and measurement of its level by repeated blood samplings is beneficial to monitoring of estrus cycle. However, since toy poodles have a small body size and thin-walled blood vessels, repeated blood samplings cause stress and affect their preparation for mating or artificial insemination (AI. Therefore, a noninvasive method for monitoring progesterone concentration should be developed. Here, we show that time-resolved fluoroimmunoassay (TF-RIA is a useful noninvasive method for determining the progesterone concentration in serum and fecal samples obtained from toy poodles. Present results demonstrate that progesterone concentrations in the fecal correlated with the serum collected in same time and the sequential changes in progesterone concentrations in the feces are paralleled in the serum. Therefore, this technique may be suitable for monitoring the estrus cycle in toy poodles.

  13. [Research on the NO2 mean concentration measurement with target differential optical absorption spectroscopy technology].

    Liu, Jin; Si, Fu-Qi; Zhou, Hai-Jin; Zhao, Min-Jie; Dou, Ke; Liu, Wen-Qing

    2013-04-01

    A new monitoring method of NO2 concentration near ground with the target difference absorption spectrum technology (Target DOAS) is introduced in the present paper. This method is based on the passive difference absorption spectrum technology. The instrument collects solar reflection spectrum of remote objectives, such as wall of building and mountain, and a specific reference spectrum is chosen to subtract the influence of trace gases from the target to atmospheric top, then integrated concentration of NO2 along the path between the target and instrument can be calculated through the differential absorption spectra inversion algorithm. Since the distance between the instrument and target is given, the mean concentration of NO2 can be derived. With developed Target DOAS instrument, NO2 concentration measurement was carried out in Hefei. And comparison was made between the target DOAS and long path difference absorption spectrometer. Good consistency was presented, proving the feasibility of this method. PMID:23841393

  14. Measurement of radon gas concentration in fertilizer samples by using nuclear track detector (CR-39)

    In the present work, we have measured the radon gas concentration in ten fertilizers samples for three kinds { mixed fertilizer (M.F), triple super phosphate (T.S.P), single super phosphate (S.S.P) } by using alpha-emitters registrations which are emitted form radon gas in (CR-39) nuclear track detector.The results obtained have shown that the highest average radon gas concentration in fertilizer samples was found in triple super phosphate sample(T.S.P.), which was (177.5Bq/m3) (Iran origin), while the lowest average radon gas concentration was found in single super phosphate (S.S.P.) sample, which was (72.2Bq/m3) (Iraq origin).The present results show that the radon gas concentration in all fertilizers samples is below the allowed limit from (International Commission of Radiation Protection) (ICRP) agency

  15. The status quo of radon concentrations and mitigation measures in underground working places of China

    LI Xiaoyan; ZHENG Baoshan; WANG Yan; WANG Xue

    2005-01-01

    By using solid-state nuclear detectors, the air radon concentrations at 87 underground working places were measured during spring, summer and winter, respectively. The survey covered 23 cities whose annual radon concentrations range from 14.9 to 246.4 Bq·m -3 with an overall arithmetic mean value of 106.7 Bq·m -3. The average annual effective dose received by people working in these underground working places was 1.6 mSv, hence the lifetime fatality risk was 1.2×10 -4. Fujian Province had the highest radon level during the survey. It is better to reduce the radon concentration heavily in summer because of higher radon concentration than in winter.

  16. Radon as an environmental risk: concentration measurements in family buildings at Cordoba city

    Measurements of radon concentration at homes are usual activities in the last years at the countries with uranium in their soils. On the other hand, the man's radiological protection about radiation is related to the environmental actions for a healthy life, but not much known for a public. The great quantities of ore with uranium can be an important source of irradiation when they are used as building materials. The soils are important too for the emanations of radon in the interior of buildings and for these reasons, the radon concentration measurements in Cordoba familiar houses were implemented in the summer of 1991. The Alpha Track Technique and the results obtained indicate the need of other measurements and a winter measurement for investigation variations of radon concentration. The typical values measured were low, about 4.13 Bq/m3 if they are compared with other Argentine values measured. This paper discusses the procedure, techniques and criteria used in the work held in Cordoba city, Argentina. (Author)

  17. Measurement of concentration and size distribution of radon decay products in homes using air cleaners

    By removing particles, air cleaners can also eliminate radon decay products. However, by removing the particles, the open-quotes unattachedclose quotes fraction of the radon progeny is increased leading to a higher dose per unit exposure. Thus, both the concentration and size distributions of the radon decay products are needed to evaluate air cleaners. Three types of room air cleaners, NO-RAD Radon Removal System, Electronic Air Cleaner and PUREFLOW Air Treatment System were tested in a single family home in Arnprior, Ontario (Canada). Semi-continuous measurements of radon gas concentration and radon decay product activity weighted size distribution were performed in the kitchen/dining room under real living conditions. The effects of air cleaners on both the concentration and size distribution of the radon decay products were measured, and their impact on the dose of radiation given to the lung tissue were examined

  18. Fiber Laser Intracavity Spectroscopy of hot water for temperature and concentration measurements

    Fomin, Alexey; Zavlev, Tatiana; Rahinov, Igor; Alekseev, Vladimir A.; Konnov, Alexander A.; Baev, Valery M.; Cheskis, Sergey

    2015-12-01

    The feasibility of temperature and concentration measurements using near-IR (˜1.5 μm) water spectra obtained by fiber laser intracavity spectroscopy was evaluated. The spectra were registered with water vapor heated in a tubular oven at temperatures between 1000 and 1300 K and in adiabatic flames where temperatures were above 1800 K. Adiabatic flames of methane were stabilized on the heat flux burner. For temperature and concentration evaluation, the observed spectra were fitted by simulated spectra calculated utilizing the HITEMP database. Several discrepancies between HITEMP data and the experiments leading to significant errors in evaluation were found. After small corrections to the database better, accuracy of the temperature (±70 K) and concentration (±20 %) measurements is obtained. A more precise spectroscopic assignment is needed to improve the accuracy of the results.

  19. Measurement of radon concentration in drinking water of Shimoga district, Karnataka, India

    This paper presents the distribution of radon activity concentration in drinking water samples and their annual effective dose exposure in Shimoga district. The radon concentrations in 38 drinking water samples were measured by using Emanometry technique. The measured radon concentration in drinking water samples ranged between 3.10 ± 0.25 and 38.50 ± 1.54 Bq l-1 with an average value of 13.60 ± 1.12 Bq l-1. This study reveals that 44.8 % drinking water samples analyzed have radon levels in excess of the EPA recommended maximum contamination level of 11.1 Bq l-1. The total mean annual effective doses of all the samples are significantly lower than the reference level of 0.1 mSv y-1. (author)

  20. Application of transcutaneous diffuse reflectance spectroscopy in the measurement of blood glucose concentration

    Wenliang Chen(陈文亮); Rong Liu(刘蓉); Houxin Cui(崔厚欣); Kexin Xu(徐可欣); Lina Lü(吕丽娜)

    2004-01-01

    In this paper, the propagation characteristics of near-infrared (NIR) light in the palm tissue are analyzed,and the principle and feasibility of using transcutaneous diffuse reflectance spectroscopy for non-invasive blood glucose detection are presented. An optical probe suitable for measuring the diffuse reflectance spectrum of human palm and a non-invasive blood glucose detection system using NIR spectroscopy are designed. Based on this system, oral glucose tolerance tests are performed to measure the blood glucose concentrations of two young healthy volunteers. The partial least square calibration model is then constructed by all individual experimental data. The final result shows that correlation coefficients of the two experiments between the predicted blood glucose concentrations and the reference blood glucose concentrations are 0.9870 and 0.9854, respectively. The root mean square errors of prediction of full cross validation are 0.54 and 0.52 mmol/1, respectively.

  1. Radium concentration and radon exhalation measurements in the water around thermal power plants of north India

    Samples of water from different thermal power plants in northern India have been collected and analyzed for radium and radon concentration. For the measurements, α-sensitive LR-115 type II plastic track detectors are used. The radium and radon levels measured in some samples are high and thus unsafe from health point of view. Based upon the available data, the radon exhalation rates have been calculated. The radium concentration varies from 1.11 to 3.11 Bql-1 and the radon concentration varies from 10.64 to 29.78 pCil-1. The radon mass exhalation rates vary from 8.95 to 25.08 mBqkg-1hr-1 and surface exhalation rates vary from 245.21 to 690.24 mBqm-12hr-1 in different water samples. (author)

  2. A calibration method of an ionization chamber for measuring 222Rn concentration

    When 222Rn concentration is measured with an ionization chamber, the conversion factor of ionization current to 222Rn concentration has been decided in individual case. A flow-type ionization chamber (the effective volume; 18 l) was used for measuring 222Rn concentration in this work. The conversion factor of this ionization chamber was obtained 1.11 (Bq/m3/fA) by the use of RaDEF standard source. From the results of three other literatures and this work, the following formula to calculate the conversion factor (a) was obtained as a function of the effective volume V (m3) of ionization chamber; a = (1.036 x 102-1) / [V·(log V + 6.908)] (Bq/m3/fA). (author)

  3. Measurement of the terrestrial and anthropogenic radionuclide concentrations in Bafra Kizilirmak delta (bird sanctuary) in Turkey

    In this study, the activity concentrations of terrestrial and anthropogenic radionuclides in the soil samples collected from Bafra Kizilirmak Delta were measured by using gamma spectrometry with an NaI(Tl) detector. The average values of activity concentrations of 238U, 232Th and 40K were found to be 37.2±2.8, 33.7±3.1 and 413.0±59.8 Bq kg-1, respectively. 137Cs was also measured in some samples. It has a mean value of 13.8±1.0 Bq kg-1. From the activity concentrations, the absorbed gamma dose rates in outdoor and the corresponding annual effective dose rates and external hazard index (Hex) were estimated. (authors)

  4. Measurement and interpretation of gas phase formaldehyde concentrations obtained during the CHABLIS campaign in coastal Antarctica

    R. A. Salmon

    2008-07-01

    Full Text Available Gas phase formaldehyde concentrations were measured during the 2004–2005 CHABLIS campaign at Halley research station, Antarctica. Data coverage span from May 2004 through to January 2005, thus capturing the majority of the year, with a wintertime minimum of near or below the instrumental detection limit rising to between 50 and 200 pptv during the austral summer. Factors controlling HCHO concentration include local chemical sources and sinks, and exchange with the snow surface. The measured seasonality is in line with previous observations from Neumayer station, with maximum in summer and minimum during the winter months, but with lower absolute concentrations throughout the year. The gas-phase production of HCHO was dominated by methane oxidation and a steady-state analysis showed that reactions of iodine and bromine species substantially reduced the predicted HCHO levels based upon in situ chemistry. This indicates a substantial additional HCHO source to be present that could be explained by a snowpack source.

  5. Passive Sampler for Measurements of Atmospheric Nitric Acid Vapor (HNO3 Concentrations

    Andrzej Bytnerowicz

    2001-01-01

    Full Text Available Nitric acid (HNO3 vapor is an important nitrogenous air pollutant responsible for increasing saturation of forests with nitrogen and direct injury to plants. The USDA Forest Service and University of California researchers have developed a simple and inexpensive passive sampler for monitoring air concentrations of HNO3. Nitric acid is selectively absorbed on 47-mm Nylasorb nylon filters with no interference from particulate NO3-. Concentrations determined with the passive samplers closely corresponded with those measured with the co-located honeycomb annular denuder systems. The PVC protective caps of standardized dimensions protect nylon filters from rain and wind and allow for reliable measurements of ambient HNO3 concentrations. The described samplers have been successfully used in Sequoia National Park, the San Bernardino Mountains, and on Mammoth Mountain in California.

  6. Sediment suspension in oscillatory flow: measurements of instantaneous concentration at high shear

    Staub, Carsten; Jonsson, Ivar G; Svendsen, Ib A.

    1996-01-01

    , resulting in intense sediment transport over a flat bed, The measurements were performed at different levels in a large oscillating water tunnel. They showed some characteristic features of the temporal concentration variation at fixed levels, including a pronounced effect of the orientation of the suction......Different syphon type suspended load probes were used together with a specially developed ''carousel'' sampler for measurements of the instantaneous sediment concentration in turbulent oscillatory flow over a sand bed, Shields parameters were well above the ripple/flat bed transition region...... tube relative to the flow. The variation with height of the average concentration is reasonably well described assuming a constant turbulent diffusivity, and the magnitude of this can be predicted relatively well using simple turbulence arguments. Two empirical formulae for the extrapolated bed...

  7. Measurement of chloride-ion concentration with long-period grating technology

    Tang, Jaw-Luen; Wang, Jian-Neng

    2007-06-01

    A simple and low-cost long-period fiber grating (LPG) sensor suited for chloride-ion concentration measurement is presented. The LPG sensor is found to be sensitive to the refractive index of the medium around the cladding surface of the sensing grating, thus offering the prospect of development of practical sensors such as an ambient index sensor or a chemical concentration indicator with high stability and reliability. We measured chloride ions in a typical concrete sample immersed in salt water solutions with different weight concentrations ranging from 0% to 25%. Results show that the LPG sensor exhibited a linear decrease in the transmission loss and resonance wavelength shift when the concentration increased. The measurement accuracy for the concentration of salt in water solution is estimated to be 0.6% and the limit of detection for chloride ions is about 0.04%. To further enhance its sensitivity for chloride concentrations, we coated a monolayer of colloidal gold nanoparticles as the active material on the grating surface of the LPG sensor. The operating principle of sensing is based on the sensitivity of localized surface plasmon resonance of self-assembled gold colloids on the grating section of the LPG. With this method, a factor of two increase in the sensitivity of detecting chemical solution concentrations was obtained. The advantages of this type of fiber-optic sensor are that it is compact, relatively simple to construct and easy to use. Moreover, the sensor has the potential capability for on-site, in vivo and remote sensing, and it has potential use as a disposable sensor.

  8. Using a Homemade Flame Photometer to Measure Sodium Concentration in a Sports Drink

    LaFratta, Christopher N.; Jain, Swapan; Pelse, Ian; Simoska, Olja; Elvy, Karina

    2013-01-01

    The purpose of this experiment was to create a simple and inexpensive flame photometer to measure the concentration of sodium in beverages, such as Gatorade. We created a nebulizer using small tubing and sprayed the sample into the base of a Bunsen burner. Adjacent to the flame was a photodiode with a filter specific for the emission of the sodium…

  9. Water leak detection in sodium heated steam generators through measurement of hydrogen concentration in sodium

    This report includes a description of apparatus for measuring hydrogen concentration in the secondary sodium system of the PHENIX reactor. The calibration method and results obtained since the commissioning of the reactor are also described. Mention is made of improvements to be built into SUPER PHENIX

  10. Sediment suspension in oscillatory flow: measurements of instantaneous concentration at high shear

    Staub, Carsten; Jonsson, Ivar G; Svendsen, Ib A.

    Different syphon type suspended load probes were used together with a specially developed ''carousel'' sampler for measurements of the instantaneous sediment concentration in turbulent oscillatory flow over a sand bed, Shields parameters were well above the ripple/flat bed transition region...

  11. The analysis of error in trace gas concentration measurements by intermodulated photoacoustic stark spectroscopy (IMPASS)

    Groot, T; Bicanic, D.; Montfort, M; Torfs, P.; Braun, R.; Van Asselt, K.

    1994-01-01

    Data collected in an actual IMPASS experiment with a static gaseous mixture (methyl fluoride/ethylene/nitrogen) of preselected concentrations were analyzed with respect to uni(bi)modality, symmetry, skeweness and kurtosis. Bimodal probability distribution function is significantly different from Gaussian suggesting the presence of "mixed" data in the measurements ; the potential cause for this phenomenon is discussed.

  12. Artifacts in measuring aerosol uptake kinetics: the roles of time, concentration and adsorption

    L. H. Renbaum

    2011-03-01

    Full Text Available In laboratory studies of organic aerosol particles reacting with gas-phase oxidants, high concentrations of radicals are often used to study on the timescale of seconds reactions which may be occurring over days or weeks in the troposphere. Implicit in this approach is the assumption that radical concentration and time are interchangeable parameters, though this has not been established. Here, the kinetics of OH- and Cl-initiated oxidation reactions of model single-component liquid organic aerosols (squalane, brassidic acid and 2-octyldodecanoic acid are studied by varying separately the radical concentration and the reaction time. Two separate flow tubes with residence times of 2 and 66 s are used, and [OH] and [Cl] are varied by adjusting either the laser photolysis fluence or the radical precursor concentration ([O3] or [Cl2], respectively used to generate the radicals. It is found that the rates measured by varying the radical concentration and the reaction time are equal only if the precursor concentrations are the same in the two approaches. Further, the rates depend on the concentrations of the precursor species with a Langmuir-type functional form suggesting that O3 and Cl2 saturate the surface of the liquid particles. It is believed that the presence of O3 inhibits the rate of OH reaction, perhaps by reacting with OH radicals or blocking surface sites, while Cl2 enhances the rate of Cl reaction by participating in a radical chain mechanism. These results have important implications for laboratory experiments in which high concentrations of gas-phase oxidants are used to study atmospheric reactions over short timescales and may explain the variability in recent measurements of the reactive uptake of OH on squalane particles in reactor systems used in this and other laboratories.

  13. Time-resolved measurements of aerosol elemental concentrations in indoor working environments

    Žitnik, M.; Kastelic, A.; Rupnik, Z.; Pelicon, P.; Vaupetič, P.; Bučar, K.; Novak, S.; Samardžija, Z.; Matsuyama, S.; Catella, G.; Ishii, K.

    2010-12-01

    We have measured the elemental concentrations in aerosols with a 2-h time resolution in two different types of working environment: a chemistry laboratory dealing with the processing of advanced nanoparticulate materials and a medium-sized machine workshop. Non-stop 10-day and 12-day samplings were performed at each location in order to determine the concentration trends during the non-working/working and weekday/weekend periods. Supplementary measurements of PM10 aerosols with a 2-day sample collection time were performed with a standard Gent PM10 sampler to compare the elemental concentrations with the time-averaged concentrations detected by the 2D step-sampler. The concentrations were determined a posteriori by analyzing the x-ray spectra of aerosol samples emitted after 3-MeV proton bombardment. The PM10 samples collected in the chemistry laboratory were additionally inspected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) to determine the chemical compositions of the individual particles. In the workshop, a total PM10 mass sampling was performed simultaneously with a minute resolution to compare the signal with typical outdoor PM10 concentration levels. A factor analysis of the time-resolved dataset points to six and eight factors in the chemistry laboratory and the machine workshop, respectively. These factors describe most of the data variance, and their composition in terms of different elements can be related to specific indoor activities and conditions. We were able to demonstrate that the elemental concentration sampling with hourly resolution is an excellent tool for studying the indoor air pollution. While sampling the total PM10 mass concentration with a minute resolution may lack the potential to identify the emission sources in a "noisy" environment, the time averaging on a day time scale is too coarse to cope with the working dynamics, even if elemental sensitivity is an option.

  14. Application of in situ-produced 10Be to the study of Australian stone line induced by termite activity

    Colin, F.; Gurarie, E.; Bourles, D.; Braucher, R.; Brown, E.; Anan, R.; Gilkes, R.; Meunier, J. D.; Varajao, C.

    2001-12-01

    The aim of this study is to understand the genesis of a stoneline sequence located at the border of the Yilgarn Craton in southwest Austrtalia. The sequence was selected because a well-defined line of siliceous pebbles traces the limit between a typical tropical saprolite and a soil almost entirely composed of termite nests, providing an opportunity to study the role of biological processes in stoneline genesis. A roadcut along the Boyup Brook Road provided the opportunity to examine and sample a 100 m wide section of weathering mantle developed on a gently sloping hill. The sequence consists, from base to top, of three main weathering layers: a gneiss- and schist-inherited yellow saprolite that includes subvertical quartz veins ; a 10 to 20 cm thick stone line composed primarily of angular quartz pebble; and a 40 to 50 cm thick dark brown surficial soil rich in both active and dormant termite nests. The distribution of these layers does not vary significantly across the hill, but quartz rich veins are most abundant in the central part of the hill. Kaolinite and quartz are the major mineralogical components throughout the sequence. There is little variation in grain size distributions, other than a modest increase in the >63 micron fractions of surface samples due to termite activity (mixing of minerals with woody and grassy debris). Chemical and mineralogical analyses were used to characterise the weathering layers and to investigate the role of termite colonies. We determined the in situ produced 10Be contents of samples collected from a depth profile through the quartz-rich schist and of pebbles from the stoneline at distances up to 40 m from central quartz veins. The 10Be depth profile shows a simple exponential decrease with depth, consistent with attenuation of cosmic ray neutrons and erosion at a rate of 20 mMyr, consistent with rates of excavation by termites. The pebbles from the stoneline have nearly constant 10Be concentrations that are approximately

  15. Thermodynamic correction of particle concentrations measured by underwing probes on fast flying aircraft

    Weigel, R.; Spichtinger, P.; Mahnke, C.; Klingebiel, M.; Afchine, A.; Petzold, A.; Krämer, M.; Costa, A.; Molleker, S.; Jurkat, T.; Minikin, A.; Borrmann, S.

    2015-12-01

    Particle concentration measurements with underwing probes on aircraft are impacted by air compression upstream of the instrument body as a function of flight velocity. In particular for fast-flying aircraft the necessity arises to account for compression of the air sample volume. Hence, a correction procedure is needed to invert measured particle number concentrations to ambient conditions that is commonly applicable for different instruments to gain comparable results. In the compression region where the detection of particles occurs (i.e. under factual measurement conditions), pressure and temperature of the air sample are increased compared to ambient (undisturbed) conditions in certain distance away from the aircraft. Conventional procedures for scaling the measured number densities to ambient conditions presume that the particle penetration speed through the instruments' detection area equals the aircraft speed (True Air Speed, TAS). However, particle imaging instruments equipped with pitot-tubes measuring the Probe Air Speed (PAS) of each underwing probe reveal PAS values systematically below those of the TAS. We conclude that the deviation between PAS and TAS is mainly caused by the compression of the probed air sample. From measurements during two missions in 2014 with the German Gulfstream G-550 (HALO - High Altitude LOng range) research aircraft we develop a procedure to correct the measured particle concentration to ambient conditions using a thermodynamic approach. With the provided equation the corresponding concentration correction factor ξ is applicable to the high frequency measurements of each underwing probe which is equipped with its own air speed sensor (e.g. a pitot-tube). ξ-values of 1 to 0.85 are calculated for air speeds (i.e. TAS) between 60 and 260 m s-1. From HALO data it is found that ξ does not significantly vary between the different deployed instruments. Thus, for the current HALO underwing probe configuration a parameterisation of

  16. Instruments and methods for measuring indoor radon and radon progeny concentrations

    Public concern about unusually high indoor concentrations of radon in the northeastern US has greatly increased the demand for reliable, inexpensive, and portable instrumentation. Different types of information are needed to completely assess the problem of indoor radon, such as: concentrations of radon, sources and emanation and health effects. Measurement accuracy, convenience and cost also merit consideration. The techniques presently used to monitor radon and progeny are sufficiently developed to meet most of these requirements and objectives for the assessment of the radiation exposure of the general public. The types of instruments used for these measurements depend on whether one is interested in a broad-based screening survey of the indoor environment for radon, an investigation to characterize radon sources and pathways, or to help establish standards and guidelines and compliance criteria. Measurement of the airborne concentrations of radon and progeny is the most important step in estimating indoor exposure levels and in identifying a potential problem. Therefore, in this paper the authors will review and evaluate the major measurement techniques, i.e., prompt or grab sampling (active and passive). Emphasis will be placed on portable, low cost instruments, both passive and active, and on proper calibration methods in atmospheres in which radon and progeny are traceable to a primary National Bureau of Standards source. Also described for the determination of radon input into the indoor environment are techniques for measuring radon exhalation from building surfaces and the underlying soil, radon in water, and radium in the soil. 36 references, 3 tables

  17. Measurements of radon concentrations in a sample representative of housing in Franche-Comte

    Three departments on four ones in Franche-Comte are classified at risk for radon: measurements are so compulsory in establishments receiving public. For the residential sector, no obligation of measurement are compulsory when french people spend 70% of their time in it. The data concerning homes are fragmentary and deserve to be completed. This campaign of measurements has confirmed the existence of radon in relatively high concentrations in Franche-Comte, including the sedimentary areas, justifying the necessity to realize a precise evaluation of the sanitary impact. The model will allow to study different strategies to reduce radon in houses. (N.C.)

  18. Novel methods of measuring nitric oxide and nitrite concentrations using cobinamide and cobalamin

    Duan, Kailin Catherine

    2012-01-01

    Nitric oxide (NO) is an important signaling molecule produced by isoforms of nitric oxide synthase in mammals. Methods of measuring NO must take into consideration the low concentrations (nanomolar to micromolar) at which it is found in the body. We developed a novel method of direct nitric oxide measurement by measuring the absorbance change of the binding of nitric oxide to cobinamide(II) (Cbi), a vitamin B12 analogue. The absorbance values of NO-Cbi change linearly at 366 nm and 469 nm as ...

  19. Application of gas chromatographic method in simultaneous measurements of helium, argon and neon concentration in groundwaters

    Najman, J.; Bielewski, J.; Sliwka, I.

    2012-04-01

    Helium concentration in groundwater is a fine indicator in water dating in a range from a hundred to tens of thousands of years. Gas chromatography (GC) measurements of helium can be used as an alternative to mass spectrometry (MS) determinations of 4He for groundwater dating [1]. Argon and neon concentrations mainly serve for determining the temperature of recharge and the air excess which is needed to correct measured values of helium concentration [2] . A chromatographic measurement system of helium, argon and neon concentration in groundwater is presented [3]. Water samples are taken from groundwater with a precise procedure without contamination with air in a special stainless steel vessels of volume equal to 2900 cm3. Helium is extracted from water samples using the head-space method. After enrichment by cryotrap method helium is analyzed in the gas chromatograph equipped with the thermal conductivity detector (TCD) with detection limit of about 2.8 ng He. The helium limit of detection of presented method is 1,2·10-8 cm3STP/gH2O [4]. We are currently working on adapting the method of cryogenic enrichment of helium concentration for simultaneous measurements of the concentration of helium, argon and neon using single sample of groundwater. Neon will be measured with the thermal conductivity detector and capillary column filled with molecular sieve 5A. Argon will be analyzed also with the thermal conductivity detector and packed column filled with molecular sieve 5A. This work was supported by grant No. N N525 3488 38 from the polish National Science Centre. [1] A. Zuber, W. Ciężkowski, K. Różański (red.), Tracer methods in hydrogeological studies - a methodological guide. Wroclaw University of Technology Publishing House, Wroclaw, 2007 (in polish). [2] P. Mochalski, Chromatographic method for the determination of Ar, Ne and N2 in water, Ph.D. thesis, Institute of Nuclear Physics Polish Academy of Sciences in Krakow, 2003 (in polish). [3] A. Żurek, P

  20. An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids

    Keene, William C.; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold

    1989-01-01

    During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH3COOH) were intercompared in central Virginia. HCOOH and CH3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH-impregnated quartz filters, K2CO3 and NaCO3-impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters using both hi-vol and lo-vol systems to measure particulate phase concentrations. Performances of the mist chamber and K2CO3-impregnated filter techniques were evaluated using zero air and ambient air spiked with HCOOH(g) and CH3COOH(g), and formaldehyde from permeation sources. The advantages and drawbacks of these methods are reported and discussed.

  1. Hydrogen Concentration and Strain Fields Near Fatigue Cracks in Pipeline Steel Measured Via Neutron Imaging

    Connolly, Matthew; Slifka, Andrew; Drexler, Elizabeth; Hydrogen Pipeline Safety Team

    Hydrogen (H2) is desirable for energy storage as it is cleaner burning and can store a larger amount of energy than an equal mass of gasoline. One problem in the development of a hydrogen economy is to find or develop materials that ensure the safe, reliable, and cost-effective flow of energy from the source to the user. It is expected steels will be needed to serve this function. However, the existing network of natural gas pipeline, for example, is constructed of ferrous materials which are susceptible to embrittlement and subsequent increased fatigue crack growth rates after exposure to hydrogen. In order to improve current modeling efforts, experimental determination of hydrogen concentration, hydrogen diffusion rates, and strain fields are required to inform and validate the model. Here we report neutron imaging measurements of the hydrogen concentration near a fatigue crack and the corresponding strain field, measured via neutron transmission Bragg edge spectroscopy. Nist Materials Measurement Laboratory, Applied Chemicals and Materials Division.

  2. Inverse estimation of radon flux distribution for East Asia using measured atmospheric radon concentration

    In this study, the 222Rn flux density distribution at surface was estimated in East Asia with the Bayesian synthesis inversion using measurement data and a long-range atmospheric 222Rn transport model. Surface atmospheric 222Rn concentrations measured at Hateruma Island in January 2008 were used. The estimated 222Rn flux densities were generally higher than the prior ones. The area-weighted mean 222Rn flux density for East Asia in January 2008 was estimated to be 44.0 mBq m-2 s-1. The use of the estimated 222Rn flux density improved the discrepancy of the model-calculated concentrations with the measurements at Hateruma Island. (authors)

  3. Equilibration correction of temporal measurements for sudden 222Rn concentration changes

    Tan, Y.; Tokonami, S.; Liu, H.; Kearfott, K. J.

    2016-02-01

    222Rn and 220Rn can be used as tracers of groundwater or submarine springs, and 222Rn in water also could indicate indoor radon problems in some regions. The half-life of 222Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min-1, which is approximately equivalent to the time required for the 222Rn-218Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed.

  4. Equilibration correction of temporal measurements for sudden 222Rn concentration changes

    222Rn and 220Rn can be used as tracers of groundwater or submarine springs, and 222Rn in water also could indicate indoor radon problems in some regions. The half-life of 222Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min−1, which is approximately equivalent to the time required for the 222Rn-218Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed

  5. New instruments and methods for measuring the concentration of radioactive products in the atmosphere

    Different recorders for radioactive aerosols have been developed for measuring the pollution of the atmosphere in laboratories or the external atmosphere. EAR 600. - Allows continuous measurement, instantaneously and 3 to 10 hours after sampling, of concentrations of α or β emitting aerosols varying between some 10-11 and some 10-8 curie per cubic metre of air. EAR 800. - Allows continuous measurement of concentration of α emitting aerosols varying between 10-11 and 10-5 curie per cubic metre of air and concentration of β emitting aerosols from 10-11 to 10-1 curie per cubic metre of air. EAR Plutonium. - Allows detection after several minutes of 1000 MPD (2 x 10-9 curie par cubic metre), and after 8 hours 1 MPD (2 x 10-12 curie per cubic metre). Two methods are used to separate the activity due to plutonium from that due to the descendants of radon and thoron: a) by amplitude discrimination, b) by RaC-RaC' and ThC-ThC' (α β ) coincidences. SP4. This system, mounted on a jeep, allows the measurement of irradiation produced on the ground by the smoke from the piles. The sensitivity is 5μR/h. A.D.I.R. - This autonomous and portable instrument is designed for the instantaneous measurement of the radon content of the atmosphere in mines. It allows the measurement of contents in air varying between 0.4 and 400 x 10-10 curie per litre of air (0.4 and 400 MPD). The measurement of radioactive fall-out is carried out after collection of this activity by a special rain gauge which comprises an adhesive surface and a tube containing ion exchange resins. The radioactivity of the fall-out varies between some 10-9 and some 10-7 curie per square metre per month. Concentrations in fission products of the atmosphere are measured after collecting on filter paper. Concentrations measured in air at ground level vary between 10-13 and 10-12 curie per cubic metre. (author)

  6. Measurement and Comparison of Organic Compound Concentrations in Plasma, Whole Blood, and Dried Blood Spot Samples

    Batterman, Stuart A.; Chernyak, Sergey; Su, Feng-Chiao

    2016-01-01

    The preferred sampling medium for measuring human exposures of persistent organic compounds (POPs) is blood, and relevant sample types include whole blood, plasma, and dried blood spots (DBS). Because information regarding the performance and comparability of measurements across these sample types is limited, it is difficult to compare across studies. This study evaluates the performance of POP measurements in plasma, whole blood and DBS, and presents the distribution coefficients needed to convert concentrations among the three sample types. Blood samples were collected from adult volunteers, along with demographic and smoking information, and analyzed by GC/MS for organochlorine pesticides (OCPs), chlorinated hydrocarbons (CHCs), polychlorinated biphenyls (PCBs), and brominated diphenyl ethers (PBDEs). Regression models were used to evaluate the relationships between the sample types and possible effects of personal covariates. Distribution coefficients also were calculated using physically-based models. Across all compounds, concentrations in plasma were consistently the highest; concentrations in whole blood and DBS samples were comparable. Distribution coefficients for plasma to whole blood concentrations ranged from 1.74 to 2.26 for pesticides/CHCs, averaged 1.69 ± 0.06 for the PCBs, and averaged 1.65 ± 0.03 for the PBDEs. Regression models closely fit most chemicals (R2 > 0.80), and whole blood and DBS samples generally showed very good agreement. Distribution coefficients estimated using biologically-based models were near one and did not explain the observed distribution. Among the study population, median concentrations of several pesticides/CHCs and PBDEs exceeded levels reported in the 2007–2008 National Health and Nutrition Examination Survey, while levels of other OCPs and PBDEs were comparable or lower. Race and smoking status appeared to slightly affect plasma/blood concentration ratios for several POPs. The experimentally

  7. Measuring and simulating atmospheric concentration trends of polychlorinated biphenyls in the Northern Hemisphere

    Hung, Hayley; Chi Lee, Sum; Wania, Frank; Blanchard, Pierrette; Brice, Ken

    Temporal trend analysis of polychlorinated biphenyls (PCB) air concentration data measured in the Canadian Arctic and around the Great Lakes in the 1990s has shown that individual PCB congeners decline at different rates in air. The atmospheric decline rate of the same congener also varied from site to site. To determine whether these site-specific variations in atmospheric trends of PCB concentrations are controlled by changes in primary emissions or various removal processes in the environment (transfer to deep sea, freshwater sediment burial, reaction with OH radicals, degradation in media other than air), the measured trends are compared to those simulated by a zonally averaged global fate and transport model using historical emission estimates and realistic and hypothetical environmental scenarios. The modelled decline rates of a specific congener in both the North Polar and the North Temperate zones are similar and mimic closely those of the historical emission estimates fed into the model, suggesting that the rate of decline of PCB air concentrations during the 1990s was mostly driven by declines in primary emission. This implies that measured air concentration data reflect primary PCB emissions as long as these continue. Under the assumption that primary emission completely ceased after 2001, the model predicted that the terrestrial surface media would eventually become the only major global PCB reservoir, and the rate of concentration decline in air then depends solely on that in soil. Also, primary emissions and volatilization from soil, respectively, are the primary input to the atmosphere before and after primary emissions stopped. The model further illustrates that even during periods when primary emissions still dominate PCB air concentrations temperature-driven cycles of air/surface exchange may be observed. Large scale re-distribution of PCBs by the grass-hopper effect can thus also occur while primary emissions are still dominant.

  8. Modeling of indoor radon concentration from radon exhalation rates of building materials and validation through measurements

    Building materials are the second major source of indoor radon after soil. The contribution of building materials towards indoor radon depends upon the radium content and exhalation rates and can be used as a primary index for radon levels in the dwellings. The radon flux data from the building materials was used for calculation of the indoor radon concentrations and doses by many researchers using one and two dimensional model suggested by various researchers. In addition to radium content, the radon wall flux from a surface strongly depends upon the radon diffusion length (L) and thickness of the wall (2d). In the present work the indoor radon concentrations from the measured radon exhalation rate of building materials calculated using different models available in literature and validation of models was made through measurement. The variation in the predicted radon flux from different models was compared with d/L value for wall and roofs of different dwellings. The results showed that the radon concentrations predicted by models agree with experimental value. The applicability of different model with d/L ratio was discussed. The work aims to select a more appropriate and general model among available models in literature for the prediction of indoor radon. -- Highlights: • The measurement of indoor radon concentration was carried out by pin hole based dosimeter. • The indoor radon concentration was calculated from different model available in the literature. A comparison of wall flux from two different approaches was carried out for different d/L ratio. • A more appropriate model for prediction of indoor radon concentration was validated

  9. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude

  10. Measurement of radon concentration in dwellings in the region of highest lung cancer incidence in India

    Monitoring of radon exhalation from soil and its concentration in indoor is found to be helpful in many investigations such as health risk assessment and others as radiation damage to bronchial cells which eventually can be the second leading cause of lung cancer next to smoking. The fact that Aizawl District, Mizoram, India has the highest lung cancer incidence rates among males and females in Age Adjusted Rate (AAR) in India as declared by Population Based Cancer Registry Report 2008 indicates the need for quantification of radon and its anomalies attached to it. Measurement of radon concentration had been carried out inside the dwellings in Aizawl district, Mizoram. A time integrated method of measurement was employed by using a solid state nuclear track detector (SSNTD) type (LR-115 films) kept in a twin cup dosimeter for measurement of concentration of radon and thoron. The dosimeters were suspended over bed rooms or living rooms in selected dwellings. They were deployed for a period of about 120 days at a time in 63 houses which were selected according to their place of location viz. fault region, places where fossil remains were found and geologically unidentified region. After the desired period of exposure, the detectors were retrieved and chemically etched which were then counted by using a spark counter. The recorded nuclear tract densities are then converted into air concentrations of Radon and Thoron

  11. Effects of Spectral Error in Efficiency Measurements of GaInAs-Based Concentrator Solar Cells

    Osterwald, C. R.; Wanlass, M. W.; Moriarty, T.; Steiner, M. A.; Emery, K. A.

    2014-03-01

    This technical report documents a particular error in efficiency measurements of triple-absorber concentrator solar cells caused by incorrect spectral irradiance -- specifically, one that occurs when the irradiance from unfiltered, pulsed xenon solar simulators into the GaInAs bottom subcell is too high. For cells designed so that the light-generated photocurrents in the three subcells are nearly equal, this condition can cause a large increase in the measured fill factor, which, in turn, causes a significant artificial increase in the efficiency. The error is readily apparent when the data under concentration are compared to measurements with correctly balanced photocurrents, and manifests itself as discontinuities in plots of fill factor and efficiency versus concentration ratio. In this work, we simulate the magnitudes and effects of this error with a device-level model of two concentrator cell designs, and demonstrate how a new Spectrolab, Inc., Model 460 Tunable-High Intensity Pulsed Solar Simulator (T-HIPSS) can mitigate the error.

  12. Measures of ozone concentrations using passive sampling in forests of South Western Europe

    Sanz, M.J. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain)]. E-mail: mjose@ceam.es; Calatayud, V. [Fundacion CEAM, Charles R. Darwin 14, Parc Tecnologic, E-46980 Paterna, Valencia (Spain); Sanchez-Pena, G. [Servicio de Proteccion de los Montes contra Agentes Nocivos, Direccion General para la Biodiversidad, Ministerio de Medio Ambiente, Gran Via de San Francisco, 4, E-28005, Madrid (Spain)

    2007-02-15

    Ambient ozone concentrations were measured with passive samplers in the framework of the EU and UN/ECE Level II forest monitoring programme. Data from France, Italy, Luxembourg, Spain and Switzerland are reported for 2000-2002, covering the period from April to September. The number of plots increased from 67 in 2000 to 83 in 2002. The year 2001 experienced the highest ozone concentrations, reflecting more stable summer meteorological conditions. Average 6-month ozone concentrations above 45 ppb were measured this year in 40.3% of the plots, in contrast with the less than 21% measured in the other 2 years. Gradients of increasing ozone levels were observed from North to South and with altitude. Comments are made on the regional trends and on the time frame of the higher ozone episodes. Also, some recommendations enabling a better comparison between plots are provided. - Ozone concentrations in forested areas of SW Europe during the period 2000-2002 showed highest values in 2001, as well as a tendency to increase towards the South and with altitude.

  13. Predicting and measurement of pH of seawater reverse osmosis concentrates

    Waly, Tarek

    2011-10-01

    The pH of seawater reverse osmosis plants (SWRO) is the most influential parameter in determining the degree of supersaturation of CaCO3 in the concentrate stream. For this, the results of pH measurements of the concentrate of a seawater reverse osmosis pilot plant were compared with pH calculations based on the CO2-HCO3 --CO3 2- system equilibrium equations. Results were compared with two commercial software programs from membrane suppliers and also the software package Phreeqc. Results suggest that the real concentrate pH is lower than that of the feed and that none of the used programs was able to predict correctly real pH values. In addition, the effect of incorporating the acidity constant calculated for NaCl medium or seawater medium showed a great influence on the concentrate pH determination. The HCO3 - and CO3 2- equilibrium equation using acidity constants developed for seawater medium was the only method able to predict correctly the concentrate pH. The outcome of this study indicated that the saturation level of the concentrate was lower than previously anticipated. This was confirmed by shutting down the acid and the antiscalants dosing without any signs of scaling over a period of 12 months. © 2011 Elsevier B.V.

  14. In-situ hydrogen concentration measurements in multilayers using neutron reflectivity

    Rehm, Ch.; Klose, F.; Nagengast, D.; Maletta, H.; Weidinger, A.

    1997-02-01

    We show that neutron reflectivity is very useful for in situ hydrogen concentration measurements in thin films, as will be demonstrated for Fe/Nb multilayers. The samples consisting of [ 26 Å Fe /X Å Nb ] ∗n with X = 15 Å-40 Å were charged with hydrogen from the gas phase at different pressures at 473 K. The hydrogen concentration in the Nb layers (no hydrogen is dissolved in Fe) can be determined from the change in the scattering contrast between Nb and Fe and the expansion of the Nb lattice due to the uptake of hydrogen. Both features are clearly visible in the reflectivity diagrams.

  15. Online Measurement of Oil Concentrations of R134a–Oil Mixtures with a Density Flowmeter.

    Bayini, Ahmed; Favrat, Daniel; Thome, John R.

    1995-01-01

    A very high accuracy, straight vibrating tube type of density flow meter has been used online to measure oil concentraiton of flowing R-134a/oil mixtures. The calibrations covered oil concentrations from 0-6 wt.% oil over the temperature range from -9.4 to 5.9°C. The oil concentrations were correlated statistically as a function of density, temperature and liquid compressibility to an average error of 0.09 wt.% oil with a 95% confidence limit of 0.21 wt.% oil. In addition, a simplified method...

  16. Optical sensor technology for simultaneous measurement of particle speed and concentration of micro sized particles

    Clausen, Casper; Han, Anpan; Kristensen, Martin;

    2013-01-01

    as a hybrid between Laser Doppler Velocimetry and Laser Particle Counters. The experimental characterization of a lab-scale setup has been performed with polystyrene particles in the range from 750 nm to 20 μm, with various particle speeds. It is shown that particle concentrations can be determined...... independently from particle speeds and is a key advantage compared to normal Laser Particle Counters.......Experimental characterization of a sensor technology that can measure particle speed and concentration simultaneously in liquids and gases is presented here. The basic sensor principle is based on an optical element that shapes a light beam into well-defined fringes. The technology can be described...

  17. Measurement of Rn-222 concentrations in building materials used in jordan

    In this work, the concentrations of the radiative inert gas Rn-222 emanated from the building materials that are commonly in jordan have been studied. For this purpose, samples of ten jordanian building materials of different masses were prepared in plastic cans sealed to passive integrated dosimeters containing CR-39 solid state nuclear track detectors which are very sensitive to alpha-particles. The Rn-222 concentrations in these samples range from 137 Bq/m3 to 267 Bq/m3 with an average of 189 Bq/m3. These levels were found to be consistent with those measured by other workers in other countries. 4 figs., 2 tabs

  18. Comparison of mercury concentrations measured at several sites in the Southern Hemisphere

    F. Slemr

    2014-12-01

    Full Text Available Our knowledge of the distribution of mercury concentrations in air of the Southern Hemisphere was until recently based mostly on intermittent measurements made during ship cruises. In the last few years continuous mercury monitoring has commenced at several sites in the Southern Hemisphere providing new and more refined information. In this paper we compare mercury measurements at several sites in the Southern Hemisphere made over a period of at least one year at each location. Averages of monthly medians show similar although small seasonal variations at both Cape Point and Amsterdam Island. A pronounced seasonal variation at Troll Research Station in Antarctica is due to frequent mercury depletion events in the austral spring. Due to large scatter and large standard deviations of monthly average median mercury concentrations at Cape Grim no systematic seasonal variation could be found there. Nevertheless, the annual average mercury concentrations at all sites during the 2007–2013 period varied only between 0.85 and 1.05 ng m−3. Part of this variability is likely due to systematic measurement uncertainties which we propose can be further reduced by improved calibration procedures. We conclude that mercury is much more uniformly distributed throughout the Southern Hemisphere than the distributions suggested by measurements made onboard ships. This finding implies (a that trends observed at one or a few sites in the Southern Hemisphere are likely to be representative for the whole hemisphere, and (b that smaller trends can be detected in shorter time periods. We also report a change of the trend sign at Cape Point from decreasing mercury concentrations in 1996–2004 to increasing concentrations since 2007.

  19. The weekly measurement deviations of indoor radon concentration from the annual arithmetic mean

    The difference between weekly measurements and the annual arithmetic mean of radon concentration CRn,Indoor was studied in the Czech Republic. The deviations were analysed for 1537 weekly measurements which were consecutively obtained in 29 rooms over a period of 1 year and the annual arithmetic mean was calculated for each particular room. The relationship of the deviations to three meteorological parameters (i.e. outside temperature, atmospheric pressure, and weekly rainfall) and to the sequential number of a calendar week was studied. The effect of atmospheric pressure and weekly rainfall was not significant. The deviation between a weekly measurement and the annual arithmetic mean depended significantly on outside weekly average temperatures. If the average outside weekly temperature was below 10 deg. C, the radon concentration was systematically higher than that of the annual arithmetic mean. The deviation variability was lower up to a temperature of 10 deg. C. If the weekly average outdoor temperature was higher than 10 deg. C, the uncertainty of a weekly measurement of radon concentration was also higher. (author)

  20. Measurements of indoor radon concentrations in the Santiago de Compostela area

    Galician soils are among those with the highest 222Rn exhalation rates in Spain. A year-round study of the indoor 222Rn concentration in buildings in the Santiago de Compostela area (Galicia, Northwest of Spain) was performed. The study is based on systematic samplings with active charcoal canisters, following a modified EPA 520/5-87-005 protocol. These measurements were complemented by others obtained using etched track dosimeters. Each data set follows a log-normal distribution, with a geometric mean of (253 ± 3) Bq m-3 for charcoal canisters and (285 ± 2.5) Bq m-3 for etched track detectors. After correcting for the different measuring conditions, the mean value of both methods differed by only 2%. A careful analysis of the seasonal dependence of our measurements did not reveal any significant seasonal variations in the 222Rn concentration. Parallel to these measurements, different meteorological parameters were recorded, which revealed a direct correlation between the indoor radon concentration and the outdoor temperature derivative with respect to time

  1. Measurements of indoor radon concentrations in the Santiago de Compostela area

    Cortina, D.; Duran, I. [Departamento de Fisica de Particulas, Grupo Experimental de Nucleos y Particulas (GENP), Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain); Llerena, J.J. [Departamento de Fisica de Particulas, Grupo Experimental de Nucleos y Particulas (GENP), Universidad de Santiago de Compostela, 15782 Santiago de Compostela (Spain)], E-mail: jjllerena@usc.es

    2008-10-15

    Galician soils are among those with the highest {sup 222}Rn exhalation rates in Spain. A year-round study of the indoor {sup 222}Rn concentration in buildings in the Santiago de Compostela area (Galicia, Northwest of Spain) was performed. The study is based on systematic samplings with active charcoal canisters, following a modified EPA 520/5-87-005 protocol. These measurements were complemented by others obtained using etched track dosimeters. Each data set follows a log-normal distribution, with a geometric mean of (253 {+-} 3) Bq m{sup -3} for charcoal canisters and (285 {+-} 2.5) Bq m{sup -3} for etched track detectors. After correcting for the different measuring conditions, the mean value of both methods differed by only 2%. A careful analysis of the seasonal dependence of our measurements did not reveal any significant seasonal variations in the {sup 222}Rn concentration. Parallel to these measurements, different meteorological parameters were recorded, which revealed a direct correlation between the indoor radon concentration and the outdoor temperature derivative with respect to time.

  2. A computational study of tomographic measurement of carbon monoxide at minor concentrations

    In order to develop a chemical species tomography system, this paper carries out various computational steps to address the problem of measuring minor species concentration using single-pass, short path-length absorption techniques in the mid-infrared. It focuses on the imaging of carbon monoxide (CO) in combustion exhaust as a case study, with an average concentration of 10 ppm over a 50 mm diameter cross-section, taking account of the presence of other absorbing species. CO absorption transitions R6, R7, R9 and R10 are identified as possible measurement targets. The joint effects of spectral absorption linewidth and laser source linewidth are considered at length, resulting in recommendations for laser linewidth to achieve appropriate levels of CO absorption signal purity. Measurement strategies are considered for achievement of the necessary sensitivity, noise and bandwidth performance. A feasible beam arrangement for tomographic imaging is discussed, providing 48 measurements of path concentration integral. Representative phantom reconstructions are presented, with encouraging results for application to such dynamic gaseous subjects

  3. Beryllium Concentrations at European Workplaces: Comparison of 'Total' and Inhalable Particulate Measurements.

    Kock, Heiko; Civic, Terence; Koch, Wolfgang

    2015-07-01

    A field study was carried out in order to derive a factor for the conversion of historic worker exposure data on airborne beryllium (Be) obtained by sampling according to the 37-mm closed faced filter cassette (CFC) 'total' particulate method into exposure concentration values to be expected when sampling using the 'Gesamtstaubprobenahmesystem' (GSP) inhalable sampling convention. Workplaces selected to represent the different copper Be work processing operations that typically occur in Germany and the EU were monitored revealing a broad spectrum of prevailing Be size distributions. In total, 39 personal samples were taken using a 37-mm CFC and a GSP worn side by side for simultaneous collection of the 'total' dust and the inhalable particulates, respectively. In addition, 20 static general area measurements were carried out using GSP, CFC, and Respicon samplers in parallel, the latter one providing information on the extra-thoracic fraction of the workplace aerosol. The study showed that there is a linear relationship between the concentrations measured with the CFC and those measured with the GSP sampler. The geometric mean value of the ratios of time-weighted average concentrations determined from GSP and CFC samples of all personal samples was 2.88. The individual values covered a range between 1 and 17 related to differences in size distributions of the Be-containing particulates. This was supported by the area measurements showing that the conversion factor increases with increasing values of the extra-thoracic fraction covering a range between 0 and 79%. PMID:25808693

  4. Toward a real-time measurement of atmospheric mercury concentrations using cavity ring-down spectroscopy

    X. Faïn

    2009-10-01

    Full Text Available A new sensor based on cavity ring-down spectroscopy (CRDS has been developed for the measurement of gaseous elemental mercury (Hg0 mass concentration with sub-ng m−3 detection limit and high temporal resolution. Cavity ring-down spectroscopy is a direct absorption technique that utilizes path lengths of up to multiple kilometers in a compact absorption cell and has a significantly higher sensitivity than conventional absorption spectroscopy. Our prototype uses a frequency-doubled, tuneable dye laser emitting pulses at ~253.65 nm with a pulse repetition frequency of 50 Hz. The dye laser incorporates a unique piezo element attached to its tuning grating allowing it to tune the laser on and off the Hg0 absorption line on a pulse to pulse basis to facilitate differential absorption measurements. Hg0 absorption measurements with this CRDS laboratory prototype are highly linearly related to Hg0 concentrations determined by a Tekran 2537B analyzer over a Hg0 concentration range of four orders of magnitude, from 0.2 ng m−3 to 573 ng m−3 implying excellent linearity of both instruments. The current CRDS instrument has a~sensitivity of 0.10 ng m−3 at 10 s time resolution. This tool opens new prospects for the study of Hg0 because of its high temporal resolution and reduced limited sample volume requirements (<0.5 l of sample air. Future applications may include ambient Hg0 flux measurements with eddy covariance techniques, which require measurements of Hg0 concentrations with sub-ng m−3 sensitivity and sub-second time resolution.

  5. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    J. C. Gong

    2010-08-01

    Full Text Available Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein in a central Beijing site in the summer and early fall of 2008 (from June to October. Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions. In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5. These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

  6. Measurement of the tritium concentration in the fractionated distillate from environmental water samples

    Standard procedures for the measurement of tritium in water samples often require distillation of an appropriate sample aliquot. This distillation process may result in a fractionation of tritiated water and regular light water due to the vapor pressure isotope effect, introducing either a bias or an additional contribution to the total tritium measurement uncertainty. The current study investigates the relative change in vapor pressure isotope effect in the course of the distillation process, distinguishing it from and extending previously published measurements. The separation factor as a quantitative measure of the vapor pressure isotope effect is found to assume values of 1.04 ± 0.036, 1.05 ± 0.026, and 1.07 ± 0.038, depending on the vigor of the boiling process during distillation of the sample. A lower heat setting in the experimental setup, and therefore a less vigorous boiling process, results in a larger value for the separation factor. For a tritium measurement in water samples where the first 5 mL are discarded, the tritium concentration could be underestimated by 4–7%. - Highlights: • Tritium measurements in environmental water samples. • Distilled samples. • Vapor pressure isotope effect. • Depending on boiling mode. • Potential underestimate of tritium activity concentration of 4–7%

  7. The measurement of thermal neutron flux depression for determining the concentration of boron in blood

    Boron neutron capture therapy (BNCT) is a form of targeted radiotherapy that relies on the uptake of the capture element boron by the volume to be treated. The treatment procedure requires the measurement of boron in the patient's blood. The investigation of a simple and inexpensive method for determining the concentration of the capture element 10B in blood is described here. This method, neutron flux depression measurement, involves the determination of the flux depression of thermal neutrons as they pass through a boron-containing sample. It is shown via Monte Carlo calculations and experimental verification that, for a maximum count rate of 1x104 counts/s measured by the detector, a 10 ppm 10B sample of volume 20 ml can be measured with a statistical precision of 10% in 32±2 min. For a source activity of less than 1.11x1011 Bq and a maximum count rate of less than 1x104 counts/s, a 10 ppm 10B sample of volume 20 ml can be measured with a statistical precision of 10% in 58±3 min. It has also been shown that this technique can be applied to the measurement of the concentration of any element with a high thermal neutron cross section such as 157Gd. (author)

  8. Potentiometric measurement of glucose concentration with an immobilized glucose oxidase/catalase electrode.

    Wingard, L B; Liu, C C; Wolfson, S K; Yao, S J; Drash, A L

    1982-01-01

    A series of enzyme electrodes for measurement of glucose have been constructed. The electrodes contain glucose oxidase immobilized on platinum, either with or without co-immobilization of catalase. When placed in buffered glucose, the enzyme electrodes show a potentiometric response to glucose with respect to a Ag/AgCl reference electrode. This response is reproducible in the physiologic range of glucose concentrations. The immobilization technique, some of the environmental variables such as oxygen concentration and pH, and several compounds that might interfere with the selectivity of the enzyme electrodes for glucose have received preliminary study. This direct potentiometric approach is undergoing further evaluation to determine the basic electrochemical mechanism responsible for the potentiometric signal and whether it can be adapted for continuous in vivo monitoring of the glucose concentration in body fluids. PMID:7172983

  9. On the long term indoor radon concentration measurements the basement of Japanese hospitals

    Long term indoor radon gas measurements using a passive monitor were conducted in the basement rooms of five hospitals, which are built in the Tokyo metropolitan area. The ventilation rate averaged over all hospital was 12.3 air change per hour (ACH). The highest radon concentration was 56.3 Bq/m3. The value averaged concentration over all hospital and all season was 20 Bq/m3. But the average of the two hospitals were twice as high as those of three others. Since the total ventilation rate integrated over a day is not different much, the reason of the concentration difference is considered to be the difference in radon emission rate from concrete wall and soil of the each hospital. Though we inquired workers about 'Environmental complaints', it do not show the direct relation between radon and environmental complaints. (author)

  10. Measurements of the radon-222 and its daughters concentrations throughout Gaza strip, Palestine

    High Radon levels are present in the granite and grandiositic rocks that. spread in sand dunes along coast of Gaza. Such materials are rich in uranium and T widely used in the construction of dwelling in the Gaza, and their contribution to high indoor Radon levels is most relevant.The present work aims to investigate approaches, measures and detection of indoor Radon level throughout Gaza Strip. Five hundred CR-39 dosimeters were distributed over six locations in the middle Yv-region of Gaza Strip. Results suggest that Radon concentrations range from l3.36 to 83.82 Bq/m3 and a maximum value of 97.01 Bq/m3.The average Radon concentrations was 37.83 Bq/m3 with standard deviation of 11.23.The results provide a framework for future studies that include a large, broader survey of Radon concentration in Palestine

  11. Measurement of tissue optical properties with optical coherence tomography: Implication for noninvasive blood glucose concentration monitoring

    Larin, Kirill V.

    Approximately 14 million people in the USA and more than 140 million people worldwide suffer from diabetes mellitus. The current glucose sensing technique involves a finger puncture several times a day to obtain a droplet of blood for analysis. There have been enormous efforts by many scientific groups and companies to quantify glucose concentration noninvasively using different optical techniques. However, these techniques face limitations associated with low sensitivity, accuracy, and insufficient specificity of glucose concentrations over a physiological range. Optical coherence tomography (OCT), a new technology, is being applied for noninvasive imaging in tissues with high resolution. OCT utilizes sensitive detection of photons coherently scattered from tissue. The high resolution of this technique allows for exceptionally accurate measurement of tissue scattering from a specific layer of skin compared with other optical techniques and, therefore, may provide noninvasive and continuous monitoring of blood glucose concentration with high accuracy. In this dissertation work I experimentally and theoretically investigate feasibility of noninvasive, real-time, sensitive, and specific monitoring of blood glucose concentration using an OCT-based biosensor. The studies were performed in scattering media with stable optical properties (aqueous suspensions of polystyrene microspheres and milk), animals (New Zealand white rabbits and Yucatan micropigs), and normal subjects (during oral glucose tolerance tests). The results of these studies demonstrated: (1) capability of the OCT technique to detect changes in scattering coefficient with the accuracy of about 1.5%; (2) a sharp and linear decrease of the OCT signal slope in the dermis with the increase of blood glucose concentration; (3) the change in the OCT signal slope measured during bolus glucose injection experiments (characterized by a sharp increase of blood glucose concentration) is higher than that measured in

  12. Associations between insulin and glucose concentrations and anthropometric measures of fat mass in Australian adolescents

    Denney-Wilson Elizabeth

    2010-08-01

    Full Text Available Abstract Background One of the most serious, yet common co-morbidities of obesity is insulin resistance, which if untreated may progress to type 2 diabetes. This paper describes the insulin and glucose concentration distributions, the prevalence of elevated insulin, the associations between insulin and body mass index (BMI, waist circumference, waist-to-height ratio (WHtR and fat mass index in a representative sample of Australian adolescents. Methods Cross-sectional population-based study of adolescent boys and girls (N = 496, mean age 15.3 years attending schools in metropolitan Sydney, Australia. Fasting venous blood collected and analysed for insulin and glucose concentrations. Height, weight, waist circumference measured, BMI and waist-to-height ratio calculated. Pubertal status self-reported. Results Glucose concentrations were normally distributed and were not associated with adiposity. Insulin concentrations were distributed logarithmically, were higher among girls than boys overall and within the same ranges of BMI and waist circumference, but were lower among girls than boys within the same ranges of fat mass adjusted for height. The prevalence of elevated insulin concentration (defined as > 100 pmol/L was 15.9% and 17.1% among boys and girls, respectively. Correlations between insulin concentration and BMI, waist circumference, WHtR and fat mass adjusted for height were 0.53, 0.49, 0.51 and 0.55, among boys, respectively, and 0.35, 0.40, 0.42 and 0.34, among girls, respectively. Conclusions Elevated insulin is highly correlated with adiposity in adolescents. BMI and WHtR are simple measures that can be used to identify young people who should be screened for insulin resistance and other co-morbidities.

  13. DNA copy number concentration measured by digital and droplet digital quantitative PCR using certified reference materials.

    Corbisier, Philippe; Pinheiro, Leonardo; Mazoua, Stéphane; Kortekaas, Anne-Marie; Chung, Pui Yan Jenny; Gerganova, Tsvetelina; Roebben, Gert; Emons, Hendrik; Emslie, Kerry

    2015-03-01

    The value assignment for properties of six certified reference materials (ERM-AD623a-f), each containing a plasmid DNA solution ranging from 1 million to 10 copies per μL, by using digital PCR (dPCR) with the BioMark™ HD System (Fluidigm) has been verified by applying droplet digital PCR (ddPCR) using the QX100 system (Bio-Rad). One of the critical factors in the measurement of copy number concentrations by digital PCR is the partition volume. Therefore, we determined the average droplet volume by optical microscopy, revealing an average droplet volume that is 8 % smaller than the droplet volume used as the defined parameter in the QuantaSoft software version 1.3.2.0 (Bio-Rad) to calculate the copy number concentration. This observation explains why copy number concentrations estimated with ddPCR and using an average droplet volume predefined in the QuantaSoft software were systematically lower than those measured by dPCR, creating a significant bias between the values obtained by these two techniques. The difference was not significant anymore when the measured droplet volume of 0.834 nL was used to estimate copy number concentrations. A new version of QuantaSoft software (version 1.6.6.0320), which has since been released with Bio-Rad's new QX200 systems and QX100 upgrades, uses a droplet volume of 0.85 nL as a defined parameter to calculate copy number concentration. PMID:25600685

  14. Real-time estimation of plasma insulin concentration from continuous glucose monitor measurements.

    de Pereda, Diego; Romero-Vivo, Sergio; Ricarte, Beatriz; Rossetti, Paolo; Ampudia-Blasco, Francisco Javier; Bondia, Jorge

    2016-07-01

    Continuous glucose monitors can measure interstitial glucose concentration in real time for closed-loop glucose control systems, known as artificial pancreas. These control systems use an insulin feedback to maintain plasma glucose concentration within a narrow and safe range, and thus to avoid health complications. As it is not possible to measure plasma insulin concentration in real time, insulin models have been used in literature to estimate them. Nevertheless, the significant inter- and intra-patient variability of insulin absorption jeopardizes the accuracy of these estimations. In order to reduce these limitations, our objective is to perform a real-time estimation of plasma insulin concentration from continuous glucose monitoring (CGM). Hovorka's glucose-insulin model has been incorporated in an extended Kalman filter in which different selected time-variant model parameters have been considered as extended states. The observability of the original Hovorka's model and of several extended models has been evaluated by their Lie derivatives. We have evaluated this methodology with an in-silico study with 100 patients with Type 1 diabetes during 25 h. Furthermore, it has been also validated using clinical data from 12 insulin pump patients with Type 1 diabetes who underwent four mixed meal studies. Real-time insulin estimations have been compared to plasma insulin measurements to assess performance showing the validity of the methodology here used in comparison with that formerly used for insulin models. Hence, real-time estimations for plasma insulin concentration based on subcutaneous glucose monitoring can be beneficial for increasing the efficiency of control algorithms for the artificial pancreas. PMID:26343364

  15. Polish national inter calibrations of measurement methods of 222Rn concentration in waters

    This paper presents the results of intercalibration exercises to measure 222Rn concentrations in water samples. In total, 11 laboratories from many Polish research and commercial institutions took part in the above-mentioned exercises. Seven of them participated in 3 intercalibration exercises organized in 2001-2003. In 2001 and 2002, the intercalibration measurements were carried out in the Sudety Mountains (at the Szczawno Zdroj and Swieradow Zdroj health resorts, respectively). During these two experiments, water samples were taken from mineral springs, considered medicinal in Poland. They are characterized by an increased CO2 concentration (0.53-2.54 g/L), as well as different values of total dissolved solids (0.15-3.82 g/L) and radon concentrations (10-1170 Bq/L), and other distinct differences in chemical composition and physical properties. In 2003, experimental measurements were carried out in water samples prepared in the Central Laboratory for Radiological Protection in Warsaw. The samples were produced by the aeration of a 10 L container filled with tap water with air enriched by 222Rn coming from a PylonTM source comprising 502.5 kBq of 226Ra. During all the intercalibration exercises, the concentration of 222Rn in 7 water samples (2, 3 and 2 in 2001, 2002 and 2003, respectively) was determined. Special care was taken to ensure the same conditions of collecting water samples for each participant. The laboratories participating in the experiments applied different techniques to determine the concentration of 222Rn in the water samples: a liquid scintillation method, gamma detectors, Lucas cells and ionization chambers. The results confirmed that keeping the containers with water samples closed tightly from the moment of collecting until the measurement was of great importance. It happened twice, in different laboratories, that a leakage in the measurement set-up (in the AlphaGUARDTM + AquaKITTM system) resulted in underestimates of 222Rn concentration

  16. Results of measurements of particulate matter concentrations inside a pig fattening facility

    Ulens, T.

    2016-01-01

    Full Text Available Description of the subject. This research note discusses the results of measurements of particulate matter concentrations inside a pig fattening facility. Objectives. The objectives of the present study were to investigate the correlations between the different size fractions of indoor particulate matter (PM inside a pig fattening facility and to investigate the evolution of particle size distribution (PSD through a fattening period and between two housing systems and two cleaning protocols. Method. Data from two consecutive fattening periods in a commercial pig barn were used. Results. Very high correlations were found between PM10 and PM2.5 indoor concentrations. Depending on the measuring instrument, high or low correlations were found between PM1 and PM10 or PM2.5 indoor concentrations. No differences in PSD could be found between the two housing systems or the two cleaning protocols. Conclusions. The results from the present study showed high correlations between the indoor concentrations of PM10 and PM2.5. In the present study, no differences in PSD were found.

  17. 10B concentration evaluation in autoradiography images by optical density measurements

    The quantification and analysis of the tracks forming the autoradiography image of a tissue section is essential for the measurement of particle emitter concentration and distribution (e.g. 10B) in the sample. Conventional counting techniques cannot be used when track density is high because of track overlapping. A densitometry supported by image analysis method suitable for these cases has been developed. Optical density measurements obtained for boron solutions of known concentrations showed a linear behavior in the range of concentrations under consideration. - Highlights: ► A nuclear tracks quantification method was developed applying optical densitometry supported by image analysis. ► It will provide information about 10B distribution in samples whose autoradiographies present high density of tracks. ► A calibration curve for optical density versus boron concentration was constructed and applied to the analysis of boron-doped silicon wafers. ► Results were compared with those from an individual counting technique, obtaining a good agreement.

  18. Gas concentration measurement by optical similitude absorption spectroscopy: methodology and experimental demonstration.

    Anselmo, Christophe; Welschinger, Jean-Yves; Cariou, Jean-Pierre; Miffre, Alain; Rairoux, Patrick

    2016-06-13

    We propose a new methodology to measure gas concentration by light-absorption spectroscopy when the light source spectrum is larger than the spectral width of one or several molecular gas absorption lines. We named it optical similitude absorption spectroscopy (OSAS), as the gas concentration is derived from a similitude between the light source and the target gas spectra. The main OSAS-novelty lies in the development of a robust inversion methodology, based on the Newton-Raphson algorithm, which allows retrieving the target gas concentration from spectrally-integrated differential light-absorption measurements. As a proof, OSAS is applied in laboratory to the 2ν3 methane absorption band at 1.66 µm with uncertainties revealed by the Allan variance. OSAS has also been applied to non-dispersive infra-red and the optical correlation spectroscopy arrangements. This all-optics gas concentration retrieval does not require the use of a gas calibration cell and opens new tracks to atmospheric gas pollution and greenhouse gases sources monitoring. PMID:27410280

  19. {sup 10}B concentration evaluation in autoradiography images by optical density measurements

    Portu, A., E-mail: portu@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, AC: C1033AAJ, Ciudad Autonoma de Buenos Aires (Argentina); Saint Martin, G., E-mail: gisaint@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina); Brandizzi, D., E-mail: brandizzi@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Laboratorio de Microespectrofotometria (LANAIS-MEF), CONICET-CNEA (Argentina); Bernaola, O.A., E-mail: bernaola@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)

    2011-12-15

    The quantification and analysis of the tracks forming the autoradiography image of a tissue section is essential for the measurement of particle emitter concentration and distribution (e.g. {sup 10}B) in the sample. Conventional counting techniques cannot be used when track density is high because of track overlapping. A densitometry supported by image analysis method suitable for these cases has been developed. Optical density measurements obtained for boron solutions of known concentrations showed a linear behavior in the range of concentrations under consideration. - Highlights: Black-Right-Pointing-Pointer A nuclear tracks quantification method was developed applying optical densitometry supported by image analysis. Black-Right-Pointing-Pointer It will provide information about {sup 10}B distribution in samples whose autoradiographies present high density of tracks. Black-Right-Pointing-Pointer A calibration curve for optical density versus boron concentration was constructed and applied to the analysis of boron-doped silicon wafers. Black-Right-Pointing-Pointer Results were compared with those from an individual counting technique, obtaining a good agreement.

  20. Measurements of radon concentration levels in thermal waters in the region of Konya, Turkey.

    Erdogan, Mehmet; Ozdemir, Fatih; Eren, Nuretdin

    2013-01-01

    (222)Rn (radon) is one of the most important sources of natural radiation to which people are exposed. It is an alpha-emitting noble gas and it can be found in various concentrations in soil, air and in different kinds of water. In this study, we present the results of radon concentration measurements in thermal waters taken from the sources in the region of Konya located in the central part of Turkey. The radon activity concentrations in 10 thermal water samples were measured by using the AlphaGUARD PQ 2000PRO radon gas analyser in spring and summer of the year 2012. We found that radon activity concentrations range from 0.60±0.11 to 70.34±3.55 kBq m(-3) and from 0.67±0.03 to 36.53±4.68 kBq m(-3) in spring and summer, respectively. We also calculated effective doses per treatment in the spas for the spring and summer seasons. It was found that the minimum and maximum effective doses per treatment are in the range of 0.09-10.13 nSv in spring and in the range of 0.1-5.26 nSv in summer. PMID:23937805

  1. Uncertainties of retrospective radon concentration measurements by multilayer surface trap detector

    The detector for retrospective radon exposure measurements is developed. The detector consists of the multilayer package of solid-state nuclear track detectors LR-115 type. Nitrocellulose films works both as α-particle detector and as absorber decreasing the energy of α-particles. The uncertainties of implanted 210Pb measurements by two- and three-layer detectors are assessed in dependence on surface 210Po activity and gross background activity of the glass. The generalized compartment behavior model of radon decay products in the room atmosphere was developed and verified. It is shown that the most influencing parameters on the value of conversion coefficient from 210Po surface activity to average radon concentration are aerosol particles concentration, deposition velocity of unattached 218Po and air exchange rate. It is demonstrated that with the use of additional information on surface to volume room ratio, air exchange rate and aerosol particles concentration the systematic bias of conversion coefficient between surface activity of 210Po and average radon concentration can be decreased up to 30 %. (N.C.)

  2. Measurements of radon concentrations in waters and soil gas of Zonguldak, Turkey

    The radon concentrations in soil-gas and water samples (in the form of springs, catchment, tap, thermal) used as drinking water or thermal were measured using a professional radon monitor AlphaGUARD PQ 2000PRO. The measured radon concentrations in water samples ranged from 0.32 to 88.22 Bq l-1. Most of radon levels in potable water samples are below the maximum contaminant level of 11 Bq l-1 recommended by the US Environmental Protection Agency. The calculated annual effective doses due to radon intake through water consumption varied from 0.07 to 18.53 mSv y-1. The radon concentrations in soil gas varied from 295.67 to 70 852.92 Bq m-3. The radon level in soil gas was found to be higher in the area close to the formation boundary thrust and faults. No correlation was observed between radon concentrations in groundwater and soil gas. Also, no significant correlation was observed between soil-gas radon and temperature, pressure and humidity. The emanation of radon from groundwater and soil gas is controlled by the geological formation and by the tectonic structure of the area. (authors)

  3. Surface exposure history using in-situ cosmogenic 10Be, 26Al and 36Cl - applications to the Australian environment

    Production of the long-lived cosmogenic radionuclides, 10Be (T1/2=1.5Ma), 26Al (0.7Ma) and 36Cl (0.3Ma), is dominated by the interaction of cosmic-rays with the upper atmosphere. They are also produced in exposed surface rocks and within the first meter or so of the Earth's crust. This is called in-situ production and although only a million atoms or so of 10Be are produced within a ten thousand year exposure period per gram of surface rock, the technique of Accelerator Mass Spectrometry (AMS) can be applied to measure this tell-tale signal. The build-up over time of these radionuclides can be utilised as radiometric clocks to elucidate the exposure history of geomorphic formations and surfaces that have experienced some event or process that delivers previously unexposed material to cosmic-ray irradiation. Hence the reconstruction of glacial chronologies (ie time a bedrock surface was uncovered by ice retreat, or deposition age of glacial moraines), development of raised river terraces and paleo-beach ridges, age of meteorite impact craters and volcanic eruptions have been addressed with the in-situ method. Moreover, geomorphological processes of landscape evolution such as surface erosion rates, continental weathering, sediment transport and deposition, uplift rates can also be studied. The in-situ method is described along with examples of cosmogenic dating projects at ANSTO. It is estimated that it works best over the time period from 5 ka to 5 Ma and can identify erosion rates ranging from 0.1 to 10 mm/ka

  4. Remote measurement of gaseous pollutant concentrations using a mobile Fourier transform interferometer system

    A commercial Fourier transform interferometer system with telescopic optics has been installed in a van and used to make long-path absorption and single-ended emission measurements of gaseous pollutant concentrations at a number of geographical locations. The system covers the IR spectra region from 650 cm-1 to 6000 cm-1 at a maximum resolution of 0.06 cm-1. For many pollutants, concentrations in the 1--10-ppb range can be detected over a 1-km path length. To date, measurements have been made in the absorption mode across fertilizer plant gypsum ponds, an oil refinery, and jet engine plumes; industrial stacks, waste gas flares, and jet engine plumes have been studied in the emission mode

  5. Quantitative hydroxyl concentration time-series measurements in turbulent nonpremixed flames.

    Renfro, M W; King, G B; Laurendeau, N M

    1999-07-20

    Quantitative hydroxyl concentration time-series measurements have been obtained by picosecond time-resolved laser-induced fluorescence in a series of methane-air and hydrogen-argon-air nonpremixed flames. The recovery of a quantitative time series is complicated by the need to account for fluctuations in the fluorescence lifetime. We have recently developed instrumentation that enables the simultaneous measurement of fluorescence signal and lifetime. The present research represents the first application of this technique to turbulent flames. The correction for hydroxyl lifetime fluctuations is shown to be significant for mean concentrations and thus probability density functions but negligible for power spectral densities (PSD's). The hydroxyl PSD's were found to vary slightly with radial and axial location in the flames and to vary significantly with Reynolds number. However, the PSD's in the H(2)-Ar-air flames are nearly identical to those in the CH(4)-air flames. PMID:18323947

  6. MEASUREMENT OF VITAMIN B12 CONCENTRATION: A REVIEW ON AVAILABLE METHODS

    Karmi O et al

    2011-01-01

    Full Text Available Vitamin B12 is a water-soluble vitamin. It is one of the eight vitamins of vitamin B complex, needed for blood and cell maturation. It helps maintain healthy nerve cells and red blood cells, and it is needed in DNA replication. Its deficiency may cause megaloblastic anemia (amidst others health issues. For these and many similar reasons, it sometimes becomes necessary to measure its concentration. This article has carefully reviewed the different methods used for measuring vitamin B12 concentration, and the unique principles involved. The principles, basically, depend on the molecular structure of Vitamin B12 and its reactions with other substances. The methods include microbiological assay and spectrophotometric methods – these are old methods: they were the first available methods, but they are still in use for reference purposes. Another method is electroluminescent (ECL which involves highly reactive materials. However, inductive-coupled plasma-mass spectrometry (ICP-MS is a very important method, which is used routinely, even in many research. On the other hand, atomic absorption spectroscopy depends on measuring the amount of energy involved in the reaction; while radioimmunoassay (RIA is a highly sensitive immunoassay technique. In addition, there are different techniques for separating and preparing samples to be used in the various measurement methods. High-performance liquid chromatography (HPLC is used for non-validate analyst, while capillary-electrophoresis (CE that have high resolving power than traditional electrophoresis, which when they are coupled with certain detectors they afford us another principle for measuring this vitamin. Choosing the best method for measuring vitamin B12 concentration depends on many factors – including the type of sample, purpose of the test, necessity of pre-processing, time limitations, cost, sensitivity, specificity.

  7. Optimized measurement of radium-226 concentration in liquid samples with radon-222 emanation.

    Perrier, Frédéric; Aupiais, Jean; Girault, Frédéric; Przylibski, Tadeusz A; Bouquerel, Hélène

    2016-06-01

    Measuring radium-226 concentration in liquid samples using radon-222 emanation remains competitive with techniques such as liquid scintillation, alpha or mass spectrometry. Indeed, we show that high-precision can be obtained without air circulation, using an optimal air to liquid volume ratio and moderate heating. Cost-effective and efficient measurement of radon concentration is achieved by scintillation flasks and sufficiently long counting times for signal and background. More than 400 such measurements were performed, including 39 dilution experiments, a successful blind measurement of six reference test solutions, and more than 110 repeated measurements. Under optimal conditions, uncertainties reach 5% for an activity concentration of 100 mBq L(-1) and 10% for 10 mBq L(-1). While the theoretical detection limit predicted by Monte Carlo simulation is around 3 mBq L(-1), a conservative experimental estimate is rather 5 mBq L(-1), corresponding to 0.14 fg g(-1). The method was applied to 47 natural waters, 51 commercial waters, and 17 wine samples, illustrating that it could be an option for liquids that cannot be easily measured by other methods. Counting of scintillation flasks can be done in remote locations in absence of electricity supply, using a solar panel. Thus, this portable method, which has demonstrated sufficient accuracy for numerous natural liquids, could be useful in geological and environmental problems, with the additional benefit that it can be applied in isolated locations and in circumstances when samples cannot be transported. PMID:26998570

  8. Estimating the relation between groundwater and river water by measuring the concentration of Rn-222

    Yoneda, Minoru; Morisawa, Shinsuke [Kyoto Univ. (Japan). Faculty of Engineering

    1997-02-01

    This study aimed to estimate the relationship between groundwater in shallow layer and river water by determining the concentrations of {sup 222}Rn and nitric nitrogen along with water temperature. The region around ca. 20 km along river A in a certain basin was chosen as a test area. The Rn concentration of groundwater was determined by Rn extracting with toluene and counting in liquid scintillation counter, whereas for river water, it was determined by activated charcoal passive collector method developed by the authors, by which the amount of Rn adsorbed on activated charcoal was estimated by Ge-solid state detector. In addition, water temperature and nitric nitrogen concentration were measured at various points in the test area. Thus, a distribution map of the three parameters was made on the basis of the data obtained in December, 1989. Since Rn concentration is generally higher in ground water than river water and the water temperature in December is higher in the former, it seems likely that the concentrations of Rn and nitric nitrogen would become higher in the area where ground water soaks into river water. Thus, the directions of ground water flow at the respective sites along river A were estimated from the data regarding the properties of ground water. (M.N.)

  9. Influence of precipitation on 7Be concentrations in air as measured by CTBTO global monitoring system

    Data collected by the International Monitoring System (IMS) during 2009–2012 were used to study influence of precipitation and relative humidity on changes in 7Be concentrations in atmosphere. The significant decrease in 7Be concentrations, corresponding to measurements collected by stations located within Intertropical Convergence Zone (ITCZ) is demonstrated. This effect can be attributed to the process of enhanced wet deposition within the ITCZ. To quantify this effect data collected by IMS stations within ITCZ were thoroughly analyzed. It was found that the atmospheric content of 7Be strongly decreases under the rain conditions. The rain mediated depletion of 7Be to half of its before rain value, needs about 62 h in case of light precipitation, while in the case of moderate precipitation about 38 h is needed. In addition the evaluated impact of humidity showed that increase in relative humidity by 20%, for example from 70% ± 5% to 90% ± 5% causes almost a double decrease in beryllium concentration in surface air. - Highlights: • Latitudinal distribution of 7Be concentrations in air is demonstrated. • The apparent residence time of 7Be aerosols may vary between 10 and 25 days. • The removal of 7Be increases with increasing air humidity and precipitation. • The significant decrease in 7Be concentrations within ITCZ is demonstrated

  10. Measurement of fluorescent probes concentration ratio in the cerebrospinal fluid for early detection of Alzheimer's disease

    Harbater, Osnat; Gannot, Israel

    2014-03-01

    The pathogenic process of Alzheimer's Disease (AD), characterized by amyloid plaques and neurofibrillary tangles in the brain, begins years before the clinical diagnosis. Here, we suggest a novel method which may detect AD up to nine years earlier than current exams, minimally invasive, with minimal risk, pain and side effects. The method is based on previous reports which relate the concentrations of biomarkers in the Cerebrospinal Fluid (CSF) (Aβ and Tau proteins) to the future development of AD in mild cognitive impairment patients. Our method, which uses fluorescence measurements of the relative concentrations of the CSF biomarkers, replaces the lumbar puncture process required for CSF drawing. The process uses a miniature needle coupled trough an optical fiber to a laser source and a detector. The laser radiation excites fluorescent probes which were prior injected and bond to the CSF biomarkers. Using the ratio between the fluorescence intensities emitted from the two biomarkers, which is correlated to their concentration ratio, the patient's risk of developing AD is estimated. A theoretical model was developed and validated using Monte Carlo simulations, demonstrating the relation between fluorescence emission and biomarker concentration. The method was tested using multi-layered tissue phantoms simulating the epidural fat, the CSF in the sub-arachnoid space and the bone. These phantoms were prepared with different scattering and absorption coefficients, thicknesses and fluorescence concentrations in order to simulate variations in human anatomy and in the needle location. The theoretical and in-vitro results are compared and the method's accuracy is discussed.

  11. Measurement of the tungsten ion concentration after forced extinction of a vacuum arc

    The concentrations of singly ionized and neutral tungsten atoms were measured by laser-induced fluorescence after the forced extinction of vacuum arcs between tungsten-copper butt contacts, 28-mm in diam and 10-mm apart. The 50-Hz current was forced to zero at its maximum of 200 A in 1.3 μs by application of a reverse voltage. Near current zero, the ion concentration of 4 x 1017 m- 3 is of the same order of magnitude as the atomic tungsten concentration, which is 6 x 1017 m- 3. While the concentration of the neutrals remains virtually constant during 20 μs after current zero, the ion concentration decays by three orders of magnitude in the same time. The decay-time constant varies from 1.9 μs close to the post-arc cathode to 3.6 μs near the post-arc anode. It is concluded that the dielectric recovery of vacuum gaps after diffuse arcs is mainly controlled by residual charge carriers

  12. Measurements of the ion concentrations and conductivity over the Arabian Sea during the ARMEX

    Siingh, Devendraa; Gopalakrishnan, V; Kamra, A K

    2009-01-01

    Measurements of the small-, intermediate-, and large-ion concentrations and the atmospheric electric conductivity of both polarities have been made over the Arabian Sea on four cruises of ORV Sagarkanya during the Arabian Sea Monsoon Experiment (ARMEX)during the monsoon and pre-monsoon seasons of 2002 and 2003. Seasonally averaged values of the total as well as polar conductivity are much higher during the monsoon than pre-monsoon season. Surprisingly, however, the concentration of small ions are less and those of large and intermediate ions are more during the monsoon than pre-monsoon season. The diurnal variations observed during the pre-monsoon season show that the nighttime small ion concentrations are about an order of magnitude higher than their daytime values. On the contrary, the daytime concentrations of the intermediate and large ions are much higher than those of their nighttime values. No such diurnal variations in ion concentrations are observed in monsoon season. Also examined are the variations...

  13. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  14. In vitro simultaneous measurements of relaxation and nitric oxide concentration in rat superior mesenteric artery

    Simonsen, Ulf; Wadsworth, Roger M; Buus, Niels Henrik; Mulvany, Michael J

    1999-01-01

    The relationship between nitric oxide (NO) concentration measured with an NO-specific microelectrode and endothelium-dependent relaxation was investigated in isolated rat superior mesenteric artery contracted with 1 μM noradrenaline.Acetylcholine (10 μM) induced endothelium-dependent simultaneous increases in luminal NO concentration of 21 ± 6 nM, and relaxations with pD2 values and maximum of 6.95 ± 0.32 and 97.5 ± 0.7 % (n = 7), respectively. An inhibitor of NO synthase, NG-nitro-L-arginine (L-NOARG, 100 μM) inhibited the relaxations and increases in NO concentration induced by acetylcholine.Oxyhaemoglobin (10 μM) reversed the relaxations and increases in NO concentrations induced by acetylcholine, S-nitroso-N-acetylpenicillamine (SNAP) and S-morpholino-sydnonimine (SIN-1), but not the relaxations induced with forskolin. Oxyhaemoglobin also decreased the NO concentration below baseline level.In the presence of L-NOARG (100 μM), a small relaxation to acetylcholine (10 μM) of noradrenaline-contracted segments was still seen; oxyhaemogobin inhibited this relaxation and decreased the NO concentration by 14 ± 4 nM (n = 4).The NO concentration-relaxation relationship for acetylcholine resembled that for SNAP and SIN-1 more than for authentic NO. Thus while 7-17 nM NO induced half-maximal relaxations in response to SNAP or SIN-1, 378 ± 129 nM NO (n = 4) was needed for half-maximal relaxation to authentic NO.The present study provides direct evidence that the relaxation of the rat superior mesenteric artery with the endothelium-dependent vasodilator acetylcholine is correlated to the endogeneous release of NO. The study also suggests that NO mediates the L-NOARG-resistant relaxations in this artery, and that there is a basal NO release. PMID:10066940

  15. Implement an Advanced Soft Measurement Method of Mine Dust Concentration Based on K-RBF Neural Network

    Hong Yu; Xuezhen Cheng; Maoyong Cao; Xiaohang Gao

    2015-01-01

    In view of the coal dust concentration measurement elements, the measurement pollution environment will reduce the measurement accuracy. The paper proposes a soft measurement method of mine dust concentration based on the K-RBF neural network theory. It takes the electrostatic signal as the measurement signal and extracts the short-term energy, RMS and rectification value of the electrostatic signal as the characteristic quantities of signal. And then a measurement method model has been creat...

  16. Examination of four different instruments for measuring the blood lactate concentration

    Medbø, Jon Ingulf; Mamen, Asgeir; Olsen, Ole Holt; Evertsen, Frank

    2000-01-01

    ABSTRACT There is incomplete information on the performance of different instruments used to measure the blood lactate concentration. We have therefore examined instruments from Yellow Springs Instruments (YSI 23L and YSI 1500), and three cheaper and simpler instruments: Dr. Lange’s LP8+, Lactate Pro from Arkray, KDK, and Accusport from Boehringer Mannheim. First a number of blood samples were analysed by standard enzymatic photofluorometry (our control method) and in additi...

  17. Noninvasive Measurement of Fecal Progesterone Concentration in Toy Poodles by Time Resolved Fluoroimmunoassay (TR-FIA)

    Satoshi Sugimura; Kaori Narita; Hideaki Yamashiro; Atsushi Sugawara; Katsuhiko Nishimori; Tsutomu Konno; Muneyoshi Yoshida; Eimei Sato

    2008-01-01

    Progesterone is an important reproductive hormone and measurement of its level by repeated blood samplings is beneficial to monitoring of estrus cycle. However, since toy poodles have a small body size and thin-walled blood vessels, repeated blood samplings cause stress and affect their preparation for mating or artificial insemination (AI). Therefore, a noninvasive method for monitoring progesterone concentration should be developed. Here, we show that time-resolved fluoroimmunoassay (TF-RIA...

  18. Measuring low radium activity concentration in water with RAD7 by means of evaporation

    Kappke, Jaqueline; Marussig, Camila G.T.; Paschuk, Sergei; Zambianchi Junior, Pedro; Correa, Janine N.; Perna, Allan Felipe Nunes; Martin, Aline, E-mail: jaquelinekappke@gmail.com, E-mail: mila_garciatb@hotmail.com, E-mail: spaschuk@gmail.com, E-mail: zambianchi@utfpr.edu.br, E-mail: janine_nicolosi@hotmail.com, E-mail: allan_perna@hotmail.com, E-mail: nocamartin@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2015-07-01

    Preliminary activity measurements of low radium concentration in mineral water by using RAD7 equipment showed high values of statistical errors. Therefore, the need to develop a new protocol for measuring and proofing the evaporation test for radium measurements in water is in place. This study evaluates the possibility of using RAD7 equipment to measure Ra-226 activity in equilibrium with Rn-222 present in water samples. The technique involves evaporation process so as to increase the Ra-226 concentration in the sample in a controlled manner and thus reduce statistical errors. Two samples were compared, 10 L sample of distilled water and a 7.75 L sample of known concentration (0.1 Bq/L). The evaporation was carried out starting with different initial volumes for both samples: 500 mL, 1000 mL, 2000 mL, 4000 mL and a 250 mL sample not subject to evaporation. All samples reached a final volume of approximately 250 mL. After evaporation, the samples were stored for 30 days until secular equilibrium was achieved between Ra-226 and Rn-222. The values obtained, by using RAD7 detector, for distilled water, as expected, are near zero averaging 0.021 ± 0.016 Bq/L. The average value found in the water of known concentration was 0.099 ± 0.011 Bq/L, also close to the expected 0.1 Bq/L. The conclusion is that the application of an evaporation process is efficient and the proposed methodology is a proven alternative to decrease the statistical errors. (author)

  19. Concentrations of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) and Their Associations with Human Semen Quality Measurements

    Raymer, James H; Michael, Larry C.; Studabaker, William B.; Olsen, Geary W.; Sloan, Carol S.; Wilcosky, Timothy; Walmer, David K.

    2011-01-01

    A total of 256 men were studied to evaluate whether serum concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) impacted semen quality or reproductive hormones. Blood and semen were collected and analyzed for perfluorochemicals and reproductive and thyroid hormones. Semen quality was assessed using standard clinical methods. Linear and logistic modeling was performed with semen profile measurements as outcomes and PFOS and PFOA in semen and plasma as explanatory var...

  20. Phylogenetic Mixtures: Concentration of Measure in the Large-Tree Limit

    Mossel, Elchanan

    2011-01-01

    The reconstruction of phylogenies from DNA or protein sequences is a major task of computational evolutionary biology. Common phenomena, notably variations in mutation rates across genomes and incongruences between gene lineage histories, often make it necessary to model molecular data as originating from a mixtureof phylogenies. Such mixed models play an increasingly important role in practice. Using concentration of measure techniques, we show that mixtures of large trees are typically identifiable. We also derive sequence-length requirements for high-probability reconstruction.

  1. Measurement of radon concentration inside uranium Exploration mines Egypt using SSNTDS

    Passive nuclear track etch detectors CR-39 and LR-115 were used to measure radon concentration in various uranium exploration sites in different galleries in the eastern desert of Egypt. The nuclear track detectors were fixed at the inner bottom of a plastic can provided with a microporous filter cover to eliminate aerosols. The cans were held upside down in different locations in these sites for about one-month, then normally processed and scanned for track density

  2. Measuring low radium activity concentration in water with RAD7 by means of evaporation

    Preliminary activity measurements of low radium concentration in mineral water by using RAD7 equipment showed high values of statistical errors. Therefore, the need to develop a new protocol for measuring and proofing the evaporation test for radium measurements in water is in place. This study evaluates the possibility of using RAD7 equipment to measure Ra-226 activity in equilibrium with Rn-222 present in water samples. The technique involves evaporation process so as to increase the Ra-226 concentration in the sample in a controlled manner and thus reduce statistical errors. Two samples were compared, 10 L sample of distilled water and a 7.75 L sample of known concentration (0.1 Bq/L). The evaporation was carried out starting with different initial volumes for both samples: 500 mL, 1000 mL, 2000 mL, 4000 mL and a 250 mL sample not subject to evaporation. All samples reached a final volume of approximately 250 mL. After evaporation, the samples were stored for 30 days until secular equilibrium was achieved between Ra-226 and Rn-222. The values obtained, by using RAD7 detector, for distilled water, as expected, are near zero averaging 0.021 ± 0.016 Bq/L. The average value found in the water of known concentration was 0.099 ± 0.011 Bq/L, also close to the expected 0.1 Bq/L. The conclusion is that the application of an evaporation process is efficient and the proposed methodology is a proven alternative to decrease the statistical errors. (author)

  3. Relationship between Urinary Triclosan and Paraben Concentrations and Serum Thyroid Measures in NHANES 2007–2008

    Koeppe, Erika S.; Ferguson, Kelly K.; Colacino, Justin A.; Meeker, John D

    2013-01-01

    Triclosan and parabens are broad spectrum antimicrobials used in a range of consumer products. In vitro and animal studies have suggested the potential for these compounds to disrupt thyroid function, though studies in humans have been limited. The objective of the study was to assess the relationship of urinary concentrations of triclosan and parabens with serum thyroid measures in a large, representative sample of the US population. We conducted an exploratory, cross-sectional analysis of d...

  4. Helium concentration measurement in tungsten fuzz-like nanostructures by means of thermal desorption spectroscopy

    Gasparyan, Yu.; Efimov, V.; Bystrov, K.

    2016-05-01

    The concentration of helium in tungsten fuzz-like nanostructures has been measured by means of thermal desorption spectroscopy. Fuzz was formed on the W surface under intensive plasma irradiation at 1500 K. The helium content was measured first in the as-irradiated sample, and then in a similar sample with the fuzz mechanically scraped from the sample surface. The difference gave the He content in the fuzz, which was estimated to be He/ W  =  (13  ±  4)%.

  5. Quantitative Measurements of Nitric Oxide Concentration in High-Pressure, Swirl-Stabilized Spray Flames

    Cooper, Clayton S.; Laurendeau, Normand M.; Hicks, Yolanda R. (Technical Monitor)

    2000-01-01

    Lean direct-injection (LDI) spray flames offer the possibility of reducing NO(sub x) emissions from gas turbines by rapid mixing of the liquid fuel and air so as to drive the flame structure toward partially-premixed conditions. We consider the technical approaches required to utilize laser-induced fluorescence methods for quantitatively measuring NO concentrations in high-pressure LDI spray flames. In the progression from atmospheric to high-pressure measurements, the LIF method requires a shift from the saturated to the linear regime of fluorescence measurements. As such, we discuss quantitative, spatially resolved laser-saturated fluorescence (LSF), linear laser-induced fluorescence (LIF), and planar laser-induced fluorescence (PLIF) measurements of NO concentration in LDI spray flames. Spatially-resolved LIF measurements of NO concentration (ppm) are reported for preheated, LDI spray flames at pressures of two to five atmospheres. The spray is produced by a hollow-cone, pressure-atomized nozzle supplied with liquid heptane. NO is excited via the Q(sub 2)(26.5) transition of the gamma(0,0) band. Detection is performed in a two nanometer region centered on the gamma(0,1) band. A complete scheme is developed by which quantitative NO concentrations in high-pressure LDI spray flames can be measured by applying linear LIF. NO is doped into the reactants and convected through the flame with no apparent destruction, thus allowing a NO fluorescence calibration to be taken inside the flame environment. The in-situ calibration scheme is validated by comparisons to a reference flame. Quantitative NO profiles are presented and analyzed so as to better understand the operation of lean-direct injectors for gas turbine combustors. Moreover, parametric studies are provided for variations in pressure, air-preheat temperature, and equivalence ratio. Similar parametric studies are performed for lean, premixed-prevaporized flames to permit comparisons to those for LDI flames

  6. Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements.

    Abda, F; Azbaid, A; Ensminger, D; Fischer, S; François, P; Schmitt, P; Pallarès, A

    2009-01-01

    In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global

  7. Comparative study of measured and modelled number concentrations of nanoparticles in an urban street canyon

    Kumar, Prashant; Garmory, Andrew; Ketzel, Matthias;

    2009-01-01

    This study presents a comparison between measured and modelled particle number concentrations (PNCs) in the 10-300 nm size range at different heights in a canyon. The PNCs were modelled using a simple modelling approach (modified Box model, including vertical variation), an Operational Street...... entire height of the canyon, showing a well-mixed region up to first ≈2 m and then decreasing PNCs with increased height. The CFD profiles do correctly reproduce the increase from road level to a height of ≈2 m; however, they do not predict the measured PNC decrease higher in the canyon. The PNC...

  8. Calculation of the radionuclides concentrations from in-situ spectrometry data measured by semiconductor spectrometer

    The computer code based on the described method was designed including calculation of conversion factors for user defined depth distribution models. Inputs of the code are peak areas of the considered radionuclides energy lines (measured in the given arrangement and calculated by any spectra analysis software), known or expected depth distribution models for individual radionuclides (including user defined models) and soil density. The activity concentrations of considered radionuclides and depth distribution models are calculated by the code. Described method was successfully tested and is used for processing of in-situ gamma spectrometry data measured by the spectrometer with semiconductor detector

  9. Measurement of radon activity concentration and determination of inhalatory indoor radiation burden in Hungarian dwellings

    Indoor radon activity concentrations were measured by LR-115 track detectors in 122 residential buildings in Hungary during 2.5 years in 3-month exposure periods. For all the buildings the mean value is 42.1 Bq/m3 and the arithmetic mean is 55.2 Bq/m3. The estimated per capita annual effective dose equivalent is 2.1 mSv based on measurements and on the recommendations of the ICRP 50. The indoor radon levels were also checked for various building materials, location of flats, seasons and geographical position. (author) 11 refs.; 8 figs.; 2 tabs

  10. Concentration and angular velocity measurement in a cyclone separator dipleg using electrical capacitance tomography

    SUN Meng; LIU Shi; LEI Jing; LI ZhiHong

    2008-01-01

    Cyclone separator is one of the main parts of the circulating fluidized bed (CFB) boiler. The separation efficiency of the cyclone separator is very important to the whole boiler. Electrical capacitance tomo-graphy (ECT) is a unique measuring technique with great potential in multiphase flow measurement. Experimental studies are carried out on the measurement of volumetric concentration and angular ve-locity using ECT. The former is determined through image reconstruction method, and the latter is measured by cross-correlating the capacitance fluctuations caused by the conveyed solids. The dis-tribution of void fraction in radial direction, the fluctuating characteristics, probability density function and the spectrum characteristics are analyzed. The feasibility and reliability of the method are verified by experimental results.

  11. Water temperature and concentration measurements within the expanding blast wave of a high explosive

    We present an application of absorption spectroscopy to directly measure temperature and concentration histories of water vapor within the expansion of a high explosive detonation. While the approach of absorption spectroscopy is well established, the combination of a fast, near-infrared array, broadband light source, and rigid gauge allow the first application of time-resolved absorption measurements in an explosive environment. The instrument is demonstrated using pentaerythritol tetranitrate with a sampling rate of 20 kHz for 20 ms following detonation. Absorption by water vapor is measured between 1335 and 1380 nm. Water temperatures are determined by fitting experimental transmission spectra to a simulated database. Water mole fractions are deduced following the temperature assignment. The sources of uncertainty and their impact on the results are discussed. These measurements will aid the development of chemical-specific reaction models and the predictive capability in technical fields including combustion and detonation science

  12. 1D Measurement of Sodium Ion Flow in Hydrogel After a Bath Concentration Jump.

    Roos, R W; Pel, L; Huinink, H P; Huyghe, J M

    2015-07-01

    NMR is used to measure sodium flow driven by a 1D concentration gradient inside poly-acrylamid (pAA) hydrogel. A sodium concentration jump from 0.5 M NaCl to 0 M NaCl is applied at the bottom of a cylindrical pAA sample. The sodium level and hydrogen level are measured as a function of time and position inside the sample for 5 days. Then a reversed step is applied, and ion flow is measured for another 5 days. During the measurement, the cylindrical sample is radially confined and allowed to swell in the axial direction. At the same time, sodium and moisture in the sample are measured on a 1D spatial grid in the axial direction. A quadriphasic mixture model (Huyghe and Janssen in Int J Eng Sci 35:793, 1997) is used to simulate the results and estimate the diffusion coefficient of sodium and chloride. The best fit results were obtained for D[Formula: see text] cm(2)/s and D[Formula: see text] cm(2)/s, at 25 degrees centigrade. Different time constants were observed for swelling and deswelling. PMID:25786888

  13. Toward new instruments for measurement of low concentration hydrogen sulfide in small-quantity aqueous solutions

    Endogenously generated hydrogen sulfide (H2S) has been found to play some important physiological roles in the nervous and cardiovascular systems, such as a neuromodulator and a vasorelaxant. These roles are in contrast to our common perception that H2S is toxic. However, whether H2S plays a positive or negative role is dependent on the H2S concentration levels in mammals. This further puts a high demand on the accurate measurement of H2S in mammals with a further desire to be real time, continuous and in vivo. Existing methods for H2S measurement require a large number of tissue samples with complex procedures, and these methods are extremely invasive. The development of new in vivo and real-time methods for measuring H2S is, however, a great challenge. In the present study, we proposed and examined five potential H2S measurement methods: (1) atomic force microscopy with coating materials, (2) Raman spectroscopy on the H2S solutions, (3) gas chromatography/mass spectroscopy (with the static headspace technique) on the H2S solutions, (4) mass spectroscopy on unfunctionalized carbon nanotubes treated with the H2S solutions and (5) Raman spectroscopy on unfunctionalized carbon nanotubes treated with the H2S solutions. Our study concluded that method (5) is the most promising one for detecting low concentration H2S in small-quantity aqueous solutions in terms of measurement resolution and non-invasiveness, but the method is not very robust

  14. Measurements of liquid film thickness, concentration, and temperature of aqueous urea solution by NIR absorption spectroscopy

    Pan, R.; Jeffries, J. B.; Dreier, T.; Schulz, C.

    2016-01-01

    A multi-wavelength near-infrared (NIR) diode laser absorption sensor has been developed and demonstrated for real-time monitoring of the thickness, solute concentration, and temperature of thin films of urea-water solutions. The sensor monitors the transmittance of three near-infrared diode lasers through the thin liquid film. Film thickness, urea mass fraction, and liquid temperature were determined from measured transmittance ratios of suitable combinations of lasers. Available laser wavelengths were selected depending on the variation of the NIR absorption spectrum of the solution with temperature and solute concentration. The spectral database was measured by a Fourier transform infrared spectrometer in the range 5500-8000 cm-1 for urea solutions between 5 and 40 wt% and temperatures between 298 and 338 K. A prototype sensor was constructed, and the sensor concept was first validated with measurements using a calibration cell providing liquid layers of variable thickness (200-1500 µm), urea mass fraction (5-40 wt%) and temperature (298-318 K). Temporal variations of film thickness and urea concentration were captured during the constant-temperature evaporation of a liquid film deposited on an optically polished heated quartz flat.

  15. Photoacoustic spectroscopy-based detector for measuring benzene and toluene concentration in gas and liquid samples

    Here we present a novel instrument for on-line, automatic measurement of benzene and toluene concentration in gas and liquid samples produced in the natural gas industry. Operation of the instrument is based on the collection of analytes on an adsorbent, separation using a chromatographic column and detection by near-infrared diode laser-based photoacoustic spectroscopy. Sample handling, measurement and data evaluation are carried out fully automatically, using an integrated, programmable electronic unit. The instrument was calibrated in the laboratory for natural gas, nitrogen and liquid glycol samples, and tested under field conditions at a natural gas dehydration unit of the MOL Hungarian Oil and Gas Company. Minimum detectable concentrations (3σm−1) were found to be 2.5 µg l−1 for benzene and 4 µg l−1 for toluene in gas samples, while 1.5 mg l−1 for benzene and 3 mg l−1 for toluene in liquid samples, which is suitable for measuring benzene and toluene concentration in natural gas and glycol samples occurring at natural gas dehydration plants

  16. Neutral beam injector oxygen impurity measurements and concentration reduction via gettering processes. Revision 1

    Kane, R.J.; Hsu, W.L.; Kerr, R.G.; Mills, B.E.; Poulsen, P.; Hibbs, S.

    1984-12-01

    We have measured the reduction of oxygen impurity levels by means of gettering within the arc chambers of the TMX-U neutral-beam injectors using the TMX-U neutral-beam test stand. Our analysis incorporated silicon surface-probe measurements and optical Doppler-shift measurements of the hydrogen alpha spectra of deuterium atoms with energies appropriate for D/sub 2/O parentage. Without gettering, the Auger electron spectroscopy analysis of an exposed silicon sample showed a large oxygen peak below the surface peak with a concentration equivalence of approximately 2% for an accelerated beam. After gettering, with either titanium or chromium getters, optical monochromator data indicated a reduction in the oxygen concentration of at least a factor of 10 whereas Auger spectroscopy data showed at least a factor-of-eight reduction. Other metallic impurities remained below the level of detection even after gettering. Additional effects observed during this study include a change in the accelerated deuterium species concentrations, loss of gettering activity, loss of arc operation, and a change in arc performance due to arc chamber gas absorption during operation.

  17. Estimation of natural potassium concentration in Romanian males by in vivo gamma-ray spectrometry measurements

    At the Whole Body Monitoring Laboratory, from IFIN-HH, Bucharest, Romania, there were performed in vivo gamma-ray spectrometry measurements on 108 Romanian males in order to evaluate the mineral natural potassium content in human body, as total value and concentration. The measurements were performed with a shadow shield whole body counter, tilted chair geometry, based on a shielded NaI(Tl) scintillation detector of 12.5 cm (diameter) x 10 cm (height) crystal size. The results revealed a calculated value of the mean total body potassium (TBK) of 135.03 ± 2.94 g and a value of 1.9 ± 0.022 g of potassium/kg of body weight for the mean body potassium concentration, for the measured males. These values are similar with the values declared for the Reference Man, in ICRP23. Correlations between total body potassium, potassium concentration and age, weight and Body Build Index were investigated and peculiar conclusions were resulted. (author)

  18. An inversion algorithm for determining area-source emissions from downwind concentration measurements.

    Lehning, M; Shonnard, D R; Chang, D P; Bell, R L

    1994-10-01

    Measuring emissions from nonuniform area sources, such as waste repository sites, has been a difficult problem. A simple but reliable method is not available. An objective method of inverting downwind concentration measurements, utilizing an assumed form of atmospheric dispersion to reconstruct total emission rate and distribution, is described in this study. The Gaussian dispersion model is compared to a more realistic model based on K-theory and similarity expressions. A sensitivity analysis is presented indicating the atmospheric conditions under which a successful application of the method could be anticipated. Field releases of sulfur hexafluoride (SF6) from a simulated area source in flat terrain were conducted to check the method, ability to reconstruct source distribution, and total emission rate. The sensitivity analysis and the field study confirm that a few ground-level concentration measurements and a simple determination of the atmospheric dispersion characteristics are sufficient, under neutral to stable conditions, to obtain the total emission rate accurately. Reconstruction of the spatial pattern of the source is possible by utilizing concentration information from samplers located on two separate ground-level receptor lines, if a shift in the wind direction occurs and if it can be assumed that the total emission rate is time invariant. A method of cross-checking the accuracy of the reconstruction, using a simultaneous tracer release, is presented. PMID:7812684

  19. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-01

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking. PMID:26730457

  20. Advancement of an Infra-Red Technique for Whole-Field Concentration Measurements in Fluidized Beds.

    Medrano, Jose A; de Nooijer, Niek C A; Gallucci, Fausto; van Sint Annaland, Martin

    2016-01-01

    For a better understanding and description of the mass transport phenomena in dense multiphase gas-solids systems such as fluidized bed reactors, detailed and quantitative experimental data on the concentration profiles is required, which demands advanced non-invasive concentration monitoring techniques with a high spatial and temporal resolution. A novel technique based on the selective detection of a gas component in a gas mixture using infra-red properties has been further developed. The first stage development was carried out using a very small sapphire reactor and CO₂ as tracer gas. Although the measuring principle was demonstrated, the real application was hindered by the small reactor dimensions related to the high costs and difficult handling of large sapphire plates. In this study, a new system has been developed, that allows working at much larger scales and yet with higher resolution. In the new system, propane is used as tracer gas and quartz as reactor material. In this study, a thorough optimization and calibration of the technique is presented which is subsequently applied for whole-field measurements with high temporal resolution. The developed technique allows the use of a relatively inexpensive configuration for the measurement of detailed concentration fields and can be applied to a large variety of important chemical engineering topics. PMID:26927127

  1. Detection limits for ferrimagnetic particle concentrations using magnetic resonance imaging based proton transverse relaxation rate measurements

    Pardoe, H [School of Physics, University of Western Australia, Crawley, Perth, WA 6009 (Australia); Chua-anusorn, W [School of Physics, University of Western Australia, Crawley, Perth, WA 6009 (Australia); Pierre, T G St [School of Physics, University of Western Australia, Crawley, Perth, WA 6009 (Australia); Dobson, J [Department of Biomedical Engineering and Medical Physics, Centre for Science and Technology in Medicine, Keele University, Thornburrow Drive, Hartshill, Stoke-on-Trent, ST4 7QB (United Kingdom)

    2003-03-21

    A clinical magnetic resonance imaging (MRI) system was used to measure proton transverse relaxation rates (R{sub 2}) in agar gels with varying concentrations of ferrimagnetic iron oxide nanoparticles in a field strength of 1.5 T. The nanoparticles were prepared by coprecipitation of ferric and ferrous ions in the presence of either dextran or polyvinyl alcohol. The method of preparation resulted in loosely packed clusters (dextran) or branched chains (polyvinyl alcohol) of particles containing of the order of 600 and 400 particles, respectively. For both methods of particle preparation, concentrations of ferrimagnetic iron in agar gel less than 0.01 mg ml{sup -1} had no measurable effect on the value of R{sub 2} for the gel. The results indicate that MRI-based R{sub 2} measurements using 1.5 T clinical scanners are not quite sensitive enough to detect the very low concentrations of nanoparticulate biogenic magnetite reported in human brain tissue. (note)

  2. Multiple 10Be records revealing the history of cosmic-ray variations across the Iceland Basin excursion

    Horiuchi, Kazuho; Kamata, Kanae; Maejima, Shun; Sasaki, Sho; Sasaki, Nobuyoshi; Yamazaki, Toshitsugu; Fujita, Shuji; Motoyama, Hideaki; Matsuzaki, Hiroyuki

    2016-04-01

    Cosmogenic 10Be is a proxy of cosmic-ray flux, and its natural records provide vital information about the past intensity variability of the geomagnetic field and solar activity. 10Be records also serve as powerful tools for global synchronization among a variety of paleoarchives and for elucidating sedimentary processes on natural remanent magnetization acquisition. However, high-resolution (multi-decadal to multi-centennial) records of 10Be are scarce, especially those older than several tens of thousands of years. Here we present multiple high-resolution 10Be records of the Iceland Basin geomagnetic excursion interval (ca. 170-200 kyr ago) obtained from sediment cores (authigenic 10Be/9Be ratio) and an ice core (atmospheric 10Be flux). Comparing sedimentary 10Be records with relative paleointensity from the same cores, we found differences in the magnetic lock-in depth, even between adjacent cores. The 10Be-proxy records from the sediment and ice cores exhibit common characteristics: an asymmetric large-scale variation, a ∼7-kyr quasi-plateau around the maximum with a characteristic mid-term depression, and multi-millennial fluctuations in cosmic-ray flux during this interval. Minimal-synchronized and stacked 10Be records show that maximum cosmic-ray flux occurred 188.5-190.0 kyr ago and was double the present flux. A wavelet analysis of the stacked curve reveals dominant 4-kyr and secondary 8-kyr periodicities, both of which can be interpreted as intrinsic geomagnetic cycles. The wavelet spectrum of the high-resolution ice-core record shows a periodicity of 1.7 kyr and somewhat intermingled multi-centennial cycles around the maxima of 10Be, which likely represent solar cycles in this period. High-resolution 10Be records from multiple paleoarchives provide both a robust proxy record of cosmic-ray flux and a valuable tool for detailed global synchronization based on cosmic-ray variations.

  3. Modeling particulate matter concentrations measured through mobile monitoring in a deletion/substitution/addition approach

    Su, Jason G.; Hopke, Philip K.; Tian, Yilin; Baldwin, Nichole; Thurston, Sally W.; Evans, Kristin; Rich, David Q.

    2015-12-01

    Land use regression modeling (LUR) through local scale circular modeling domains has been used to predict traffic-related air pollution such as nitrogen oxides (NOX). LUR modeling for fine particulate matters (PM), which generally have smaller spatial gradients than NOX, has been typically applied for studies involving multiple study regions. To increase the spatial coverage for fine PM and key constituent concentrations, we designed a mobile monitoring network in Monroe County, New York to measure pollutant concentrations of black carbon (BC, wavelength at 880 nm), ultraviolet black carbon (UVBC, wavelength at 3700 nm) and Delta-C (the difference between the UVBC and BC concentrations) using the Clarkson University Mobile Air Pollution Monitoring Laboratory (MAPL). A Deletion/Substitution/Addition (D/S/A) algorithm was conducted, which used circular buffers as a basis for statistics. The algorithm maximizes the prediction accuracy for locations without measurements using the V-fold cross-validation technique, and it reduces overfitting compared to other approaches. We found that the D/S/A LUR modeling approach could achieve good results, with prediction powers of 60%, 63%, and 61%, respectively, for BC, UVBC, and Delta-C. The advantage of mobile monitoring is that it can monitor pollutant concentrations at hundreds of spatial points in a region, rather than the typical less than 100 points from a fixed site saturation monitoring network. This research indicates that a mobile saturation sampling network, when combined with proper modeling techniques, can uncover small area variations (e.g., 10 m) in particulate matter concentrations.

  4. Development of an equipment for atmospheric krypton sampling, purification, concentration and 85Kr measurement

    Full text: The aim of this work is to develop an automated equipment for krypton sampling, concentration, and purification, and for 85Kr measurement. A potential interest of such an equipment is the detection of undeclared reprocessing activities as 10-35 TBq of 85Kr are emitted per kg of reprocessed Pu. Based on experience acquired during development of the 'Spalax' Noble Gas Equipment for CTBT implementation, we realize a laboratory prototype. This equipment was conceived according to the following technical specifications: i) fully automated sampling, treatment (concentration and purification), and measurement; ii) trapping at ambient temperature (no cryogenic cooling); iii) a 6-hour duty cycle; iv) 85Kr measurement thanks to a proportional counter; v) obtention of about 0.5 cm3 of krypton. This krypton volume provides a detection capability of about 100 mBq.m-3 of 85Kr over background, assuming given performance of the proportional counter (efficiency, background) and given precision over stable krypton volume determination. The prototype is composed of four distinct stages which perform successively the following steps: i) a first purification and pre-concentration; ii) purification; iii) further concentration; iv) detection of 85Kr. As a first-step krypton purification and pre-concentration, we use a semi-permeative membrane, as for the 'Spalax' equipment. Nevertheless, membranes are less 'efficient' for krypton than for xenon. Therefore, we conducted a specific optimization of the operating conditions for krypton. Finally, this membrane provides an efficient purification (O2, H2O, CO2 are eliminated) and krypton pre-concentration in nitrogen by about a factor of three. A strong pressure of about 7 bars in entrance is necessary. Air equivalent processed volume in 6 hours is about 1 m3. The purification stage provides an ambient temperature adsorption of noble gases on high specific area active charcoal bed thanks to two columns inserted in two tubular ovens

  5. 大气生成宇宙成因核素10Be在中国黄土中的应用研究进展%Review on the application of the atmospheric produced10Be in Chinese loess

    孔祥辉; 周卫健; 武振坤; 杜雅娟; 赵国庆; 谢兴俊

    2016-01-01

    .Materials and Methods The publications of loess10Be studies are reviewed here. Among them, the papers published between 1980’s and 2006 are used to discuss the sources, formation, chemical behavior and its climatic implications in Chinese loess, the others published after 2006 are used to show that the loess10Be are good proxy for paleogeomagnetic variations tracing and paleorainfall reconstruction.Results The10Be in Chinese loess is mainly from atmosphere where it is produced via cosmic-ray spallation. The chemical leaching experiments with acid solutions showed that the10Be in loess and paleosols is strongly bound to soil particles and the mobility due to dissolution is very little. The measurements of10Be concentrations in loess as a function of grain size indicated that the10Be is preferred to be adsorbed on small size mineral grains due to larger surface areas. The variation of loess10Be record is similar to the magnetic susceptibility which is well correlated with marineδ18O, so it can be used to reconstruct the climatic variations. In addition, the10Be was also exploited to establish the chronology of loess-paleosol sequences based on the correlation between10Be andδ18O. Because the production rate of10Be in atmosphere is regulated by the Earth’s magnetic ifeld intensity, i.e., when the geomagnetic ifeld intensity is strong, the lfux of galactic cosmic rays penetrating into the Earth’s atmosphere is signiifcantly attenuated by scattering off the magnetic ifeld, resulting in decreased10Be production rate, and vice versa,10Be is a useful tool for the geomagnetic variations tracing studies. However, the efforts of using10Be to extract the geomagnetic ifeld signal from Chinese loess was much more dififcult than that in marine sediments. In Chinese loess, there are two sources of loess10Be: some10Be comes from remobilized dust that fell to Earth at some time in the past, whereas a second component derives from atmospheric fallout of new10Be recently generated by

  6. Instruments to measure radon-222 activity concentration or exposure to radon-222. Intercomparison 2014

    According to the Directive 96/29/EURATOM the monitoring of occupational radiation exposures shall base on individual measurements carried out by an approved dosimetric service. Pursuant to the European Directive an approved dosimetric service is a body responsible for the calibration, reading or interpretation of individual monitoring devices.., whose capacity to act in this respect is recognized by the competent authorities. This concept will also be applied to radon services issuing passive radon measurement devices. Passive radon measurement devices1 using solid state nuclear track detectors or electrets are recommended for individual monitoring of exposures to radon. German regulations lay down that radon measuring devices are appropriate for purposes of occupational radiation monitoring if the devices are issued by recognized radon measurement services, and the measurement service submits devices of the same type issued for radon monitoring to regular intercomparisons conducted by the Bundesamt fuer Strahlenschutz (BfS). A radon measuring service is recognized by the competent authority if it proves its organisational and technical competence, e. g. by accreditation. These regulations have been introduced in the area of occupational radiation exposures. Nevertheless, it is recommended that radon measuring services which carry out radon measurements in other areas (e.g. dwellings) should subject themselves to these measures voluntarily. The interlaboratory comparisons comprise the organization, exposure, and evaluation of measurements of radon activity concentration or exposure to radon. The comparisons only concern radon-222; radon-220 is not in the scope. Radon services being interested can get further information from the European Information System on Proficiency Testing Schemes (EPTIS) and from the BfS websites.

  7. Combined radiation-protective and radiation-sensitizing agents. IV. Measurement of intracellular protector concentrations

    Radiosensitization of hypoxic V79 Chinese hamster cells by 0.5 mM misonidazole at approximately 0-4 degrees C is substantially enhanced by pretreating the cells overnight with 0.1 mM buthionine sulfoximine, which lowers the cellular glutathione content to 5% of control values (from 4 mM to approximately 0.2 mM). The enhanced sensitization is reversed by concentrations of exogenous cysteine that are much lower (0.02 mM) than the original glutathione content. Reduced Co-enzyme A affords reversal of the enhancing effect at concentrations of about 1 mM. Sodium ascorbate gives no protection at all even at concentrations of 2 mM. The intracellular concentration of the reducing agents was measured using a spin-through oil technique. There was no diffusion of Co-A (MW greater than 750) or ascorbate (excluded by charge) into the cells. In contrast, cysteine was rapidly concentrated by factors of 4-10, even at the low temperatures used. Extracellular ascorbate's inability to radioprotect argues against electron transfer across the cell membrane as a mechanism for radioprotection. This mechanism could have explained the ability of exogenous thiols to radioprotect in former studies using glutathione, and in the present studies using Co-A. The potential of cysteine to be concentrated by cells poses a problem in the interpretation of exogenous protection by non-diffusing thiols, since trace contamination by cysteine could lead to the actual protection observed. Cysteine could also be formed by exchange reactions of exogenous thiols with the disulfide of cysteine, present in all media formulations

  8. Inferring DOC export mechanisms from high-frequency, instream UV-VIS concentration measurements

    Oosterwoud, Marieke; Musolff, Andreas; Keller, Toralf; Fleckenstein, Jan

    2015-04-01

    The flux of soil-derived dissolved organic carbon (DOC) is a significant term in terrestrial carbon budgets and, as a result, a dominant link between terrestrial and aquatic ecosystems. Concentrations of dissolved organic carbon in streams and rivers have been increasing in many parts of the world. Providers of drinking water from surface water reservoirs are increasingly facing problems as elevated DOC concentrations cause higher costs for removal and potentially to toxic by-products during chlorination. Mitigating these problems requires a mechanistic understanding of the controls and dynamics of DOC export from catchments. High frequency measurements using UV-vis absorbance as a proxy for DOC concentrations allow for improved evaluation of DOC concentration-discharge relationships in catchments. In addition, several UV-vis absorbance proxies (both single and multiple wavelength) can be used as an indicator of DOC quality. These relationships allow quantification of net DOC export, and may additionally provide new insights into the mechanisms that control DOC export dynamics. We aimed to evaluate the response and interaction of DOC concentrations and quality between a riparian zone soil and stream under different hydrological conditions. UV-vis sensors were installed in both the riparian soil and stream of two headwater catchments, the Hassel and Rappbode, in the Harz Mountains in Germany. The two headwater catchments are approximately equal in size, however, differ in their land-use. The Hassel catchment is dominated by agricultural land-use, whereas the Rappbode catchment is mainly forested. The DOC concentration-discharge relationships show intricate hysteretic behavior, which differs between locations and shifts in time. The rich data-set will allow for a characterization of space and time patterns of DOC export as well as changes in its quality, providing valuable new insights into the hydrologic mechanisms that govern the delivery of DOC to streams.

  9. Measurement of mass transfer coefficient in direct contact sulfuric acid concentration for IS process

    Hydrogen is expected to serve as a clean secondary energy, because it can be manufactured from water, used in a variety of energy end-use sectors as fuel, and returned to water after burning. For the realization of hydrogen energy system, development of efficient and economical hydrogen production methods is required to meet the future huge demand of hydrogen. The Iodine-Sulfur (IS) process is a promising candidate of such hydrogen production methods, in which water reacts with iodine and sulfur dioxide to produce hydrogen iodide and sulfuric acid (Bunsen reaction) and the produced acids are then decomposed to produce hydrogen and oxygen, respectively. This study is concerned with the development of IS process equipment named direct contact sulfuric acid concentrator, in which gaseous mixture produced by thermal decomposition of sulfuric acid contacts directly with sulfuric acid solution. In the concentrator, the high temperature heat of the decomposed gas is recovered and used to concentrate sulfuric acid solution and, at the same time, the undecomposed sulfuric acid is condensed and separated from the decomposition products of sulfur dioxide and oxygen. Although the concept is very attractive from the viewpoint of the development of compact and efficient sulfuric acid concentrator, little is known on the heat and mass transfer relevant to the concentrator. Therefore, experimental methods were discussed to acquire the gas-phase mass transfer coefficient required for the optimal design of the concentrator. Assuming the use of wetted-wall column and also of the sulfuric acid of azeotropic composition as the test solution which could eliminate the liquid-phase mass transfer resistance, the column specification and the measurement conditions were determined by which flooding could be avoided and surface wetting could be assured, as well. (author)

  10. Measurements of radon concentration (circular DGS/VS5 no.99 289 from May 20, 1999 - public health)

    This regulatory text is a complement to the circular no 99-46 from January 27, 1999 concerning the measurements of radon concentration inside public buildings. It precise the sanitary rules and interpretation procedure concerning the radon measurements performed inside public buildings: campaign of measurements, expert appraisement, localization of the rooms with the highest concentration and evaluation of the technical solutions. (J.S.)

  11. Development of a transfer standard for the measurement of low Rn-222 activity concentration in air

    A large volume transfer standard has been developed to calibrate commercial radon measurement devices in a homogeneous Rn-222 reference atmosphere. The transfer standard serves for the realization, maintenance and dissemination of the unit Bq/m3 below 1 kBq/m3. The transfer standard consists of a multi-wire impulse ionization chamber, electronic measurement equipment and the corresponding software. The multi-wire impulse ionization chamber is composed of two parallel printed boards. Between the boards, 478 vertical electrode wires are soldered in to include a volume of 10 L. In the dependency of the energy, the α-particles of Rn-222 and the decay products are detected in the active volume of the multi-wire impulse ionization chamber. By means of the measurement software an α-energy spectrum is produced. Via different algorithms, the activity concentration of the Rn-222 reference atmosphere is determined. - Highlights: • Transfer standard with a volume of 10 L developed for Rn-222. • Activity concentration below 1 kBq/m3 measured with low statistical uncertainties. • Calibration conversion with combined relative standard uncertainty of <2% achieved

  12. Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

    Keskinen, J.; Hautanen, J.; Laitinen, A. [Tampere Univ. of Technology (Finland). Physics

    1997-10-01

    The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

  13. A simple model for reconstructing geomagnetic field intensity with (10)~Be production rate and its application in Loess studies

    J.; Warren; BECK

    2008-01-01

    A simple model for reconstructing the paleomagnetic field intensity with (10)~Be production rate was used for the first time in Loess (10)~Be studies of Luochuan profile. Using the LGM (Last Glacial Maxmium) method, the climatic effects and geomagnetic modulation effects on loess (10)~Be was separated and in turn the 80 ka geomagnetic excursion sequence reconstructed, of which the globally remarkable geomagnetic excursion events such as the Laschamp (42 ka), Mono Lake (32 ka) during the Last Glacial period were revealed and the paleo-geomagnetic intensity curve from Loess (10)~Be over the past 80 ka was quantitatively reconstructed. The reconstructed paleo-intensity fits well with the paleo-intensity curves (SINT200 and NAPIS75), which indicates the significance of global criterion of the (10)~Be paleo- intensity curve and the future direction of loess (10)~Be tracing studies. Results show the irregular vari-ability of the East Asian monsoon precipitation in Loess Plateau is the main cause that has resulted in the ambiguity of the geomagnetic modulation of the (10)~Be record in the loess, and the intrinsic source component of the loess (10)~Be and inherited fraction of magnetic susceptibility (SUS) are characterized by the "quasi-homogeneous distribution" manner.

  14. Correspondence between hair cortisol concentrations and 30-day integrated daily salivary and weekly urinary cortisol measures.

    Short, Sarah J; Stalder, Tobias; Marceau, Kristine; Entringer, Sonja; Moog, Nora K; Shirtcliff, Elizabeth A; Wadhwa, Pathik D; Buss, Claudia

    2016-09-01

    Characterization of cortisol production, regulation and function is of considerable interest and relevance given its ubiquitous role in virtually all aspects of physiology, health and disease risk. The quantification of cortisol concentration in hair has been proposed as a promising approach for the retrospective assessment of integrated, long-term cortisol production. However, human research is still needed to directly test and validate current assumptions about which aspects of cortisol production and regulation are reflected in hair cortisol concentrations (HCC). Here, we report findings from a validation study in a sample of 17 healthy adults (mean±SD age: 34±8.6 yrs). To determine the extent to which HCC captures cumulative cortisol production, we examined the correspondence of HCC, obtained from the first 1cm scalp-near hair segment, assumed to retrospectively reflect 1-month integrated cortisol secretion, with 30-day average salivary cortisol area-under-the curve (AUC) based on 3 samples collected per day (on awakening, +30min, at bedtime) and the average of 4 weekly 24-h urinary free cortisol (UFC) assessments. To further address which aspects of cortisol production and regulation are best reflected in the HCC measure, we also examined components of the salivary measures that represent: (1) production in response to the challenge of awakening (using the cortisol awakening response [CAR]), and (2) chronobiological regulation of cortisol production (using diurnal slope). Finally, we evaluated the test-retest stability of each cortisol measure. Results indicate that HCC was most strongly associated with the prior 30-day integrated cortisol production measure (average salivary cortisol AUC) (r=0.61, p=0.01). There were no significant associations between HCC and the 30-day summary measures using CAR or diurnal slope. The relationship between 1-month integrated 24-h UFC and HCC did not reach statistical significance (r=0.30, p=0.28). Lastly, of all cortisol

  15. The role and importance of ozone for atmospheric chemistry and methods for measuring its concentration

    Marković Dragan M.

    2003-01-01

    Full Text Available Depending on where ozone resides, it can protect or harm life on Earth. The thin layer of ozone that surrounds Earth acts as a shield protecting the planet from irradiation by UV light. When it is close to the planet's surface, ozone is a powerful photochemical oxidant that damage, icons frescos, museum exhibits, rubber, plastic and all plant and animal life. Besides the basic properties of some methods for determining the ozone concentration in working and living conditions, this paper presents a detailed description of the electrochemical method. The basic properties of the electrochemical method are used in the construction of mobile equipment for determining the sum of oxidants in the atmosphere. The equipment was used for testing the determination of the ozone concentration in working rooms, where the concentration was at a high level and caused by UV radiation or electrostatic discharge. According to the obtained results, it can be concluded that this equipment for determining the ozone concentration in the atmosphere is very powerful and reproducible in measurements.

  16. Measurement of the strontium and calcium concentrations in the Mumbai Harbour Bay

    Strontium and calcium concentration (mg/l) measurements were done in the surface sea water samples collected from six different locations of Mumbai Harbour Bay (MHB). Samples were analysed by Atomic Absorption spectrophotometer. Standard addition method was used to get the concentration of one sample. Secondary standards were prepared based on this. All the samples were analysed using the secondary standards. The results showed the variation of Strontium and Calcium as 5.9-9.3 mg/l and 331-480 mg/I respectively, as against the universally accepted values of Strontium (ie. 8 mg/l) and Calcium (ie. 400 mg/I). It was found that though the concentration of Strontium and Calcium varied, the ratio Ca/Sr remained nearly the same (49.8 to 54.8), hence it may not affect the radiochemical procedure of nitrate separation used for separation of 90Sr from Ca in MHB. Final recovery calculation of Strontium should take into account the variations in concentration of Strontium. (author)

  17. A method for concentrating organic dyes: colorimetric measurements of nitric oxides and sialic acids.

    Lalezari, Parviz; Lekhraj, Rukmani; Casper, Diana

    2011-09-01

    A new method for extraction and concentration of organic dyes that uses a reagent composed of a nonionic detergent mixed with an alcohol is described. We have observed that water-soluble organic dyes are also soluble in nonionic detergents and can be extracted by adding salt, which separates the dye-detergent component from the aqueous phase. We have also found that mixing nonionic detergents with alcohols markedly reduces their viscosity and produces stable, free-flowing, and effective reagents for color extraction. On the basis of these observations, we used a mixture of Triton X-100 and 1-butanol and observed that water-soluble natural and synthetic chromophores, as well as dyes generated in biochemical reactions, can be extracted, concentrated, and analyzed spectrophotometrically. Trypan blue and phenol red are used as examples of synthetic dyes, and red wine is used as an example of phenolic plant pigments. Applications for quantification of nitric oxides and sialic acids are described in more detail and show that as little as 0.15 nmol of nitric oxide and 0.20 nmol of sialic acid can be detected. A major advantage of this method is its ability to concentrate chromophores from dye-containing solutions that otherwise cannot be measured because of their low concentrations. PMID:21605540

  18. Satellite passive microwave measurements of sea ice concentration: an optimal algorithm and challenges

    N. Ivanova

    2015-02-01

    Full Text Available Sea ice concentration has been measured globally with satellite microwave radiometers for over 30 years. However there is still a need for better understanding of corresponding challenges and consequently identifying an optimal method for sea ice concentration retrieval suitable for climate monitoring. The method should minimize inter-sensor calibration discrepancies and sensitivity to error sources with climatic trends (e.g. atmospheric water vapour and water surface roughening by wind. This article presents the results of an extensive algorithm inter-comparison and validation experiment. Thirty sea ice algorithms entered the experiment where their skills were evaluated over low and high sea ice concentrations, thin ice and areas covered by melt ponds. In addition, atmospheric correction of input brightness temperatures and dynamic tie-points approach were suggested. A selection of thirteen algorithms is shown in the article to demonstrate the results. Based on the findings, an optimal approach was suggested to retrieve sea ice concentration globally for climate monitoring purposes.

  19. Concentration and excretion of contrast agents during oral cholecystography as measured by computed tomography in dogs

    Nine healthy mongrel dogs were given 2 consecutive doses of 1 of 3 cholecystographic contrast agents (iopanoic acid, sodium ipodate, and sodium tyropanoate), followed by daily computed tomograms (CT) and abdominal radiographs in a randomized crossover study in order to determine: (a) the maximum time for excretion of the contrast material from the gallbladder, (b) the maximum time for elimination of contrast material from the blood, and (c) the correlation between the density of the gallbladder on CT and the actual concentration of iodine in the gallbladder bile. In all 9 animals gallbladder opacification disappeared on CT within 4 days after administration of the contrast material. Plain abdominal radiographs did not show gallbladder opacification after 2 1/2 days. Daily blood iodine measurements showed that all of the contrast material was cleared from the blood within 7 days after administration. In 7 dogs CT imaging of the gallbladder was followed by percutaneous aspiration of bile from the gallbladder using CT guidance. There was a direct linear correlation between the actual concentration of iodine in the bile and the density of the gallbladder on CT (r = 0.925). This suggests that CT measurements can be used to determine the concentration of contrast agents in the gallbladder during oral cholecystography. (orig.)

  20. Concentration and excretion of contrast agents during oral cholecystography as measured by computed tomography in dogs

    Hunter, T.B.; Fon, G.T.; Capp, M.P.; Berk, R.N.

    1981-10-15

    Nine healthy mongrel dogs were given 2 consecutive doses of 1 of 3 cholecystographic contrast agents (iopanoic acid, sodium ipodate, and sodium tyropanoate), followed by daily computed tomograms (CT) and abdominal radiographs in a randomized crossover study in order to determine: (a) the maximum time for excretion of the contrast material from the gallbladder, (b) the maximum time for elimination of contrast material from the blood, and (c) the correlation between the density of the gallbladder on CT and the actual concentration of iodine in the gallbladder bile. In all 9 animals gallbladder opacification disappeared on CT within 4 days after administration of the contrast material. Plain abdominal radiographs did not show gallbladder opacification after 2 1/2 days. Daily blood iodine measurements showed that all of the contrast material was cleared from the blood within 7 days after administration. In 7 dogs CT imaging of the gallbladder was followed by percutaneous aspiration of bile from the gallbladder using CT guidance. There was a direct linear correlation between the actual concentration of iodine in the bile and the density of the gallbladder on CT (r = 0.925). This suggests that CT measurements can be used to determine the concentration of contrast agents in the gallbladder during oral cholecystography.

  1. Analysis and methodology for measuring oxygen concentration in liquid sodium with a plugging meter

    Oxygen concentration in liquid sodium is a critical measurement in assessing the potential for corrosion damage in sodium-cooled fast reactors (SFRs). There has been little recent work on sodium reactors and oxygen detection. Thus, the technical expertise dealing with oxygen measurements within sodium is no longer readily available in the U.S. Two methods of oxygen detection that have been investigated are the plugging meter and the galvanic cell. One of the overall goals of the Univ. of Wisconsin's sodium research program is to develop an affordable, reliable galvanic cell oxygen sensor. Accordingly, attention must first be dedicated to a well-known standard known as a plugging meter. Therefore, a sodium loop has been constructed on campus in effort to develop the plugging meter technique and gain experience working with liquid metal. The loop contains both a galvanic cell test section and a plugging meter test section. Consistent plugging results have been achieved below 20 [wppm], and a detailed process for achieving effective plugging has been developed. This paper will focus both on an accurate methodology to obtain oxygen concentrations from a plugging meter, and on how to easily control the oxygen concentration of sodium in a test loop. Details of the design, materials, manufacturing, and operation will be presented. Data interpretation will also be discussed, since a modern discussion of plugging data interpretation does not currently exist. (authors)

  2. Measurements of 222Rn activity concentration in domestic water sources in Penang, northern peninsular Malaysia.

    Muhammad, B G; Jaafar, M S; Azhar, A R; Akpa, T C

    2012-04-01

    Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively. PMID:21642647

  3. Evaluation of correlating factors between 238U concentration measured in fine and course atmospheric particles

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 μm aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM10), defined as those particles with less than 10 μm aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM10, PI2.5 and PI1, as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report 238U activity concentration results. (author)

  4. Measured physicochemical characteristics and biosolids-borne concentrations of the antimicrobial Triclocarban (TCC).

    Snyder, Elizabeth Hodges; O'Connor, George A; McAvoy, Drew C

    2010-06-01

    Triclocarban (TCC) is an active ingredient in antibacterial bar soaps, a common constituent of domestic wastewater, and the subject of recent criticism by consumer advocate groups and academic researchers alike. Activated sludge treatment readily removes TCC from the liquid waste stream and concentrates the antimicrobial in the solid fraction, which is often processed to produce biosolids intended for land application. Greater than half of the biosolids generated in the US are land-applied, resulting in a systematic release of biosolids-borne TCC into the terrestrial and, potentially, the aquatic environment. Multiple data gaps in the TCC literature (including basic physicochemical properties and biosolids concentrations) prevent an accurate, quantitative risk assessment of biosolids-borne TCC. We utilized the USEPA Office of Prevention, Pesticides, and Toxic Substances (OPPTS) harmonized test guidelines to measure TCC solubility and log K(ow) values as 0.045 mg L(-1) and 3.5, respectively. The measured physicochemical 2 properties differed from computer model predictions. The mean concentration of TCC in 23 biosolids representative of multiple sludge processing methods was 19+/-11 mg kg(-1). PMID:20385403

  5. Evaluation of correlating factors between {sup 238}U concentration measured in fine and course atmospheric particles

    Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva, E-mail: cmp@cdtn.b, E-mail: vmfj@cdtn.b, E-mail: aab@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Dias, Fabiana Ferrari, E-mail: fdias@cnen.gov.b [Brazilian Nuclear Energy Commission (CNEN-/MG), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas (LAPOC)

    2009-07-01

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 mum aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM{sub 10}), defined as those particles with less than 10 mum aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM{sub 10}, PI{sub 2.5} and PI{sub 1}, as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report {sup 238}U activity concentration results. (author)

  6. Radon and Thoron Concentration measurement of Ground water in Kufa City by using RAD7 detector

    Radon (222Rn) and Thoron (220Rn) concentration in the groundwater samples and their annual effective dose exposure were measured in the Kufa city - Iraq.It is measured by Durridge RAD-7 radon-in-air monitor, RAD-H2O new technique with closed loop aeration concept.Study was identified on the map at the city of Kufa, by GIS.It is found that Radon and Thoron concentration in 20 groundwater samples of studied area.The range is between (0.267- 5.662), (0-0.7486)Bq L-1 respectively, the EPA's maximum contaminant level (MCL) of 11.1 Bq L-1.Also, obtain this study independent of groundwater physical and chemical properties such as (PH and EC) on the radon concentration.The total annual effective dose resulting from radon in groundwater of studied samples were significantly lower than the UNSCEAR and WHO recommended limit for members of the public of 1 mSv.y-1

  7. Spatial concentration of population in Serbia 1981-2011 measured with the Hoover index

    Šantić Danica

    2014-01-01

    Full Text Available Population distribution reflects the integrity of natural, social, economic and historical factors of the geospace, relevant both for fundamental and applied research. Complex spatial structure of the contemporary distribution of population in the world, and Serbia as well, during history was determined by human migrations of complex scope and determinants. The aim of this paper was to describe and analyze the geographical redistribution of the population by using the Hoover index as a measure of the redistribution. This measure was introduced by Edgar Hoover in 1936 and it has been widely used in geography. By computing this index, we can allocate the region of population concentration and deconcentration in Serbia. General conceptual framework of concentration and dispersion of population at different geographical levels is presented here. These differences in the achieved level of concentration in Serbia are correlated with the historical development of population, transition from an agrarian into industrial society, and process of urbanization and migration in the last sixty years.

  8. Measurement of 222Rn concentration in drinking water in Sakarya, Turkey

    In this paper, the first measurement of 222Rn concentrations in drinking water from wells, springs and bottled waters in the city of Sakarya, Turkey was presented. The measurements were performed using RAD 7, a solid-state alpha detector, with RAD H2O (radon in water) accessory manufactured by Durridge Company, Inc. The measured activity concentrations ranged from 1.98 to 20.80 Bq l-1 with an average value of 9.05 Bq l-1 for well water, from 0.75 to 59.65 Bq l-1 with an average value of 13.78 Bq l-1 for spring water and from 0.75 to 22.8 Bq l-1 with an average value of 5.41 Bq l-1 for bottled water. Although these results indicated relatively high 222Rn concentrations compared with that from other parts of the Turkey, they are still below the World Health Organization recommended level of 100 Bq l-1 for radon. Using the measured activities of 222Rn, the age-dependent associated committed effective doses due to the ingestion of 222Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from 222Rn were estimated to range from 2.59 to 205.97 μSv y-1, from 1.55 to 123.28 μSv y-1 and from 1.31 to 104.48 μSv y-1 for age groups 1-2, 8-12 and >17 y, respectively. (authors)

  9. Methane concentration and isotopic composition measurements with a mid-infrared quantum-cascade laser

    Kosterev, A. A.; Curl, R. F.; Tittel, F. K.; Gmachl, C.; Capasso, F.; Sivco, D. L.; Baillargeon, J. N.; Hutchinson, A. L.; Cho, A. Y.

    1999-01-01

    A quantum-cascade laser operating at a wavelength of 8.1 micrometers was used for high-sensitivity absorption spectroscopy of methane (CH4). The laser frequency was continuously scanned with current over more than 3 cm-1, and absorption spectra of the CH4 nu 4 P branch were recorded. The measured laser linewidth was 50 MHz. A CH4 concentration of 15.6 parts in 10(6) ( ppm) in 50 Torr of air was measured in a 43-cm path length with +/- 0.5-ppm accuracy when the signal was averaged over 400 scans. The minimum detectable absorption in such direct absorption measurements is estimated to be 1.1 x 10(-4). The content of 13CH4 and CH3D species in a CH4 sample was determined.

  10. Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

    der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F; M?riaux, A

    2006-01-13

    We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.

  11. Ozone sonde cell current measurements and implications for observations of near-zero ozone concentrations in the tropical upper troposphere

    Vömel, H.; K. Diaz

    2010-01-01

    Laboratory measurements of the Electrochemical Concentration Cell (ECC) ozone sonde cell current using ozone free air as well as defined amounts of ozone reveal that background current measurements during sonde preparation are neither constant as a function of time, nor constant as a function of ozone concentration. Using a background current, measured at a defined timed after exposure to high ozone may often overestimate the real background, leading to artificially low ozone concentrations i...

  12. Comparison of sources of submicron particle number concentrations measured at two sites in Rochester, NY

    Sources contributing to the submicron particles (100-470 nm) measured between January 2002 and December 2007 at two different New York State Department of Environmental Conservation (NYS DEC) sites in Rochester, NY were identified and apportioned using a bilinear receptor model, positive matrix factorization (PMF). Measurements of aerosol size distributions and number concentrations for particles in the size range of 10-500 nm have been made since December 2001 to date in Rochester. The measurements are being made using a scanning mobility particle sizer (SMPS) consisting of a DMA and a CPC (TSI models 3071 and 3010, respectively). From December 2001 to March 2004, particle measurements were made at the NYS DEC site in downtown Rochester, but it was moved to the eastside of Rochester in May 2004. Each measurement period was divided into three seasons i.e., winter (December, January, and February), summer (June, July, and August), and the transitional periods (March, April, May, September, October, and November) so as to avoid experimental uncertainty resulting from too large season-to-season variability in ambient temperature and solar photon intensity that would lead to unstable/non-stationary size distributions. Therefore, the seasons were analyzed independently for possible sources. Ten sources were identified at both sites and these include traffic, nucleation, residential/commercial heating, industrial emissions, secondary nitrate, ozone- rich secondary aerosol, secondary sulfate, regionally transported aerosol, and a mixed source of nucleation and traffic. These results show that the measured total outdoor particle number concentrations in Rochester generally vary with similar temporal patterns, suggesting that the central monitoring site data can be used to estimate outdoor exposure in other parts of the city.

  13. IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes.

    Siekmann, Lothar; Bonora, Roberto; Burtis, Carl A; Ceriotti, Ferruccio; Clerc-Renaud, Pascale; Férard, Georges; Ferrero, Carlo A; Forest, Jean-Claude; Franck, Paul F H; Gella, F Javier; Hoelzel, Wieland; Jørgensen, Poul Jørgen; Kanno, Takashi; Kessner, Art; Klauke, Rainer; Kristiansen, Nina; Lessinger, Jean-Marc; Linsinger, Thomas P J; Misaki, Hideo; Mueller, Mathias M; Panteghini, Mauro; Pauwels, Jean; Schiele, Françoise; Schimmel, Heinz G; Vialle, Arlette; Weidemann, Gerhard; Schumann, Gerhard

    2002-06-01

    This paper is the first in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and with the certification of reference preparations. Other parts deal with: Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic fication of Four Reference Materials for the Determination of Enzymatic Activity of y-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation. PMID:12211661

  14. Toward real-time measurement of atmospheric mercury concentrations using cavity ring-down spectroscopy

    X. Faïn

    2010-03-01

    Full Text Available Cavity ring-down spectroscopy (CRDS is a direct absorption technique that utilizes path lengths up to multiple kilometers in a compact absorption cell and has a significantly higher sensitivity than conventional absorption spectroscopy. This tool opens new prospects for study of gaseous elemental mercury (Hg0 because of its high temporal resolution and reduced sample volume requirements (<0.5 l of sample air. We developed a new sensor based on CRDS for measurement of (Hg0 mass concentration. Sensor characteristics include sub-ng m−3 detection limit and high temporal resolution using a frequency-doubled, tuneable dye laser emitting pulses at ~253.65 nm with a pulse repetition frequency of 50 Hz. The dye laser incorporates a unique piezo element attached to its tuning grating allowing it to tune the laser on and off the Hg0 absorption line on a pulse-to-pulse basis to facilitate differential absorption measurements. Hg0 absorption measurements with this CRDS laboratory prototype are highly linearly related to Hg0 concentrations determined by a Tekran 2537B analyzer over an Hg0 concentration range from 0.2 ng m−3 to 573 ng m−3, implying excellent linearity of both instruments. The current CRDS instrument has a sensitivity of 0.10 ng Hg0 m−3 at 10-s time resolution. Ambient-air tests showed that background Hg0 levels can be detected at low temporal resolution (i.e., 1 s, but also highlight a need for high-frequency (i.e., pulse-to-pulse differential on/off-line tuning of the laser wavelength to account for instabilities of the CRDS system and variable background absorption interferences. Future applications may include ambient Hg0 flux measurements with eddy covariance techniques, which require measurements of Hg0 concentrations with sub-ng m−3 sensitivity and sub-second time

  15. Volatile organic compound concentrations and emission rates measured over one year in a new manufactured house

    Hodgson, Alfred T.; Nabinger, Steven J.; Persily, Andrew K.

    2004-09-01

    A study to measure indoor concentrations and emission rates of volatile organic compounds (VOCs), including formaldehyde, was conducted in a new, unoccupied manufactured house installed at the National Institute of Standards and Technology (NIST) campus. The house was instrumented to continuously monitor indoor temperature and relative humidity, heating and air conditioning system operation, and outdoor weather. It also was equipped with an automated tracer gas injection and detection system to estimate air change rates every 2 h. Another automated system measured indoor concentrations of total VOCs with a flame ionization detector every 30 min. Active samples for the analysis of VOCs and aldehydes were collected indoors and outdoors on 12 occasions from August 2002 through September 2003. Individual VOCs were quantified by thermal desorption to a gas chromatograph with a mass spectrometer detector (GC/MS). Formaldehyde and acetaldehyde were quantified by high performance liquid chromatography (HPLC). Weather conditions changed substantially across the twelve active sampling periods. Outdoor temperatures ranged from 7 C to 36 C. House air change rates ranged from 0.26 h{sup -1} to 0.60 h{sup -1}. Indoor temperature was relatively constant at 20 C to 24 C for all but one sampling event. Indoor relative humidity (RH) ranged from 21% to 70%. The predominant and persistent indoor VOCs included aldehydes (e.g., formaldehyde, acetaldehyde, pentanal, hexanal and nonanal) and terpene hydrocarbons (e.g., a-pinene, 3-carene and d-limonene), which are characteristic of wood product emissions. Other compounds of interest included phenol, naphthalene, and other aromatic hydrocarbons. VOC concentrations were generally typical of results reported for other new houses. Measurements of total VOCs were used to evaluate short-term changes in indoor VOC concentrations. Most of the VOCs probably derived from indoor sources. However, the wall cavity was an apparent source of

  16. Energy Yield Determination of Concentrator Solar Cells using Laboratory Measurements: Preprint

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

    2015-09-14

    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 to 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. 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.

  17. Quantitative autoradiography measurement of CA-MoV18 antigen concentration in ovarian carcinomas

    Concentrations of CA-MoV18 antigen in ovarian tumor and normal ovarian tissue samples were measured. Quantitative autoradiography was performed in 33 ovarian tissue samples with radiolabeled MoV18 monoclonal antibodies. Among them 22 samples were ovarian carcinomas, 7 samples were benign ovarian tumors and 4 samples were normal ovarian tissues. Among 19 serous ovarian carcinomas, 17 had MoV 18 antigen expression, ranging from 1.30 to 59.28 pmol/g tissue, 3 mutinous ovarian carcinomas and 11 nonmalignant ovaries (7 benign tumors and 4 normal tissues) were not detectable MoV 18 antigen. CA-MoV18 antigen was expressed in serous ovarian carcinomas. The concentration of CA-MoV 18 antigen was correlated with labelled antibodies (%ID/g) in tumor tissue

  18. Applications of Kalman filtering to real-time trace gas concentration measurements

    Leleux, D. P.; Claps, R.; Chen, W.; Tittel, F. K.; Harman, T. L.

    2002-01-01

    A Kalman filtering technique is applied to the simultaneous detection of NH3 and CO2 with a diode-laser-based sensor operating at 1.53 micrometers. This technique is developed for improving the sensitivity and precision of trace gas concentration levels based on direct overtone laser absorption spectroscopy in the presence of various sensor noise sources. Filter performance is demonstrated to be adaptive to real-time noise and data statistics. Additionally, filter operation is successfully performed with dynamic ranges differing by three orders of magnitude. Details of Kalman filter theory applied to the acquired spectroscopic data are discussed. The effectiveness of this technique is evaluated by performing NH3 and CO2 concentration measurements and utilizing it to monitor varying ammonia and carbon dioxide levels in a bioreactor for water reprocessing, located at the NASA-Johnson Space Center. Results indicate a sensitivity enhancement of six times, in terms of improved minimum detectable absorption by the gas sensor.

  19. Measurements of environmental radon-222 concentrations in indoors and outdoors in Egypt

    The major contribution to population exposure from natural radiation arises from the inhalation of the decay products of radon. Substantial surveys are being conducted by several investigators to estimate the indoor and outdoor exposure nationally and to discover regional variations. In this work, radon concentration in the indoor and outdoor air was determined using the can technique and employing CR-39 solid state nuclear track detector for lengthy exposures. The range of radon-222 activity in this survey was 54 ... 299 pCi.m-3 in Cairo, 22 ... 171 pCi.m-3 in Alexandria and 89 ... 370 pCi.m-3 in Asiut. Measurements carried out in Aswan and Sinai ranged between 98 ... 411 pCi.m-3. Values of indoors and outdoors radon concentrations were found to vary with geographic location, season and height above ground. Further work is going on to study the different parameters affecting the levels of the environmental radon. (orig.)

  20. Application of γ ray attenuation technology in measuring gas-solid two-phase concentration distribution in the cyclone separator

    The gas-solid two-phase concentration distribution in the Φ 260 mm cyclone separator in the fluidized bed setup was measured with γ-ray attenuation technology. On the assumption that concentration distribution is axial symmetry, the concentration distribution model was deduced. The model could give the concentration distribution image based on radial measuring data. The reconstruction result is more truly reflect the concentration field distribution rule in the cyclone separator, especially shows that a higher solids concentration gradient near the wall. Comparing with the measuring result get by optical fiber method, both are consistent in the distribution and value of solids concentration, which verify the feasibility and reliability of this measuring method. (authors)

  1. Plasma assisted measurements of alkali metal concentrations in pressurized combustion processes

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland). Dept. of Physics

    1996-12-01

    The plasma assisted method for continuous measurement of alkali concentrations in product gas flows of pressurized energy processes will be tested and applied at the 1.6 MW PFBC/G facility at Delft University of Technology in the Netherlands. During the reporting period the alkali measuring device has been tested under pressurized conditions at VTT Energy, DMT, Foster-Wheeler Energia and ABB Carbon. Measurements in Delft will be performed during 1996 after installation of the hot gas filter. The original plan for measurements in Delft has been postponed due to schedule delays in Delft. The results are expected to give information about the influence of different process conditions on the generation of alkali vapours, the comparison of different methods for alkali measurement and the specific performance of our system. This will be the first test of the plasma assisted measurement method in a gasification process. The project belongs to the Joule II extension program under contract JOU2-CT93-0431. (author)

  2. National and Regional Surveys of Radon Concentration in Dwellings. Review of Methodology and Measurement Techniques

    Reliable, comparable and 'fit for purpose' results are essential requirements for any decision based on analytical measurements. For the analyst, the availability of tested and validated sampling and analytical procedures is an extremely important tool for carrying out such measurements. For maximum utility, such procedures should be comprehensive, clearly formulated and readily available to both the analyst and the customer for reference. In the specific case of radon surveys, it is very important to design a survey in such a way as to obtain results that can reasonably be considered representative of a population. Since 2004, the Environment Programme of the IAEA has included activities aimed at the development of a set of procedures for the measurement of radionuclides in terrestrial environmental samples. The development of radon measurement procedures for national and regional surveys started with the collection and review of more than 160 relevant scientific papers. On the basis of this review, this publication summarizes the methodology and the measurement techniques suitable for a population representative national or regional survey on radon concentration in the indoor air of dwellings. The main elements of the survey design are described and discussed, such as the sampling scheme, the protocols, the questionnaire and the data analysis, with particular attention to the potential biases that can affect the representativeness of the results. Moreover, the main measurement techniques suitable for national surveys on indoor radon are reviewed, with particular attention to the elements that can affect the precision and accuracy of the results

  3. Implement an Advanced Soft Measurement Method of Mine Dust Concentration Based on K-RBF Neural Network

    Hong Yu

    2015-04-01

    Full Text Available In view of the coal dust concentration measurement elements, the measurement pollution environment will reduce the measurement accuracy. The paper proposes a soft measurement method of mine dust concentration based on the K-RBF neural network theory. It takes the electrostatic signal as the measurement signal and extracts the short-term energy, RMS and rectification value of the electrostatic signal as the characteristic quantities of signal. And then a measurement method model has been created due to the dust concentration network study. The method shows the high speediness, little measurement error and high precision characteristic after it compared with the simulation modeling and performance evaluation of BP soft measurement method as well as the traditional optical measurement method. The method can be used to coal mine to realize real-time rapid detection of dust concentration.

  4. Fast time resolution measurements of high concentrations of iodine above a Laminaria Digitata seaweed bed

    Ball, Stephen; Adams, Thomas; Leblanc, Catherine; Potin, Philippe

    2013-04-01

    We report observations of extremely large concentrations of molecular iodine (I2) measured in situ above a seaweed bed composed of laminaria digitata (90%) and laminaria hyperborea (10%) growing in its natural habitat. Measurements were made off the coast of Roscoff in Brittany, France, during day-time low tides on several days in September and November 2012 with the greatest tidal amplitudes. Iodine was quantified using a portable, battery-powered broadband cavity enhanced absorption spectrometer (BBCEAS) deployed from the in-shore research vessel "Aurelia" operated by the Station Biologique de Roscoff. For the 5 second integration times used here, the BBCEAS instrument has a detection limit for iodine of 12 pptv (parts per trillion by volume). The boat was anchored above the seaweed bed before it was exposed to air by the ebbing tide; the boat was grounded on the seaweed bed around the tidal minimum, and then refloated as the incoming tide covered the seaweed. I2 concentrations were strongly anti-correlated with water depth. Initially little I2 was seen above background levels whilst the blades of the seaweed plants were floating on the water surface. However several hundred pptv of I2 was observed within a few minutes of the plants' stipes breaking the surface and first blades coming to rest on rocks out of the water. Iodine concentrations increased further as the tide ebbed, typically peaking around 1500 pptv around the tidal minimum (by which time the seaweed had been exposed for 45 minutes). I2 concentrations decreased rapidly back to background levels as the returning tide submerged the seaweeds. The concentration profiles showed a lot of high frequency structure, with I2 concentrations commonly varying by a factor 2 (or more) within 60 seconds. Additionally the profiles of I2 emitted from the seaweeds immediately below the instrument's inlet typically sat on a smoothly-varying background of approximately 100 pptv, which we attribute to I2 from other more

  5. An X-ray fluorescence system for measuring trace element concentrations in breast tissue

    X-ray fluorescence is being used as a technique for measuring concentrations of trace elements in breast tissue samples, both healthy and pathological. The aim is to establish the levels of some trace elements in normal tissue and subsequently compare with those in cancerous, as there are indications that there is a correlation between elevated concentrations of some elements in breast tissue and development of cancer. As a first step of these pilot studies we are investigating four such elements, Fe, Ca, Zn and Cu, but we plan to expand the study to include Se and Rb. The tissue samples are kept at -85 deg C and are stored in thin walled polypropylene tubes of 8 mm diameter, which can be unsealed from one end so that the samples can be exposed to the beam. The experimental set-up consists of a high output tungsten target X-ray source, a secondary target from which characteristic X-rays of an appropriate energy are produced, a sample holder and a Si detector. The geometry is highly collimated in order to promote a high signal to noise ratio for the fluorescence X-rays from the sample. The measurements will be compared to reference solutions of various concentrations of the elements of interest. The aim is to establish a calibration curve for each element, from which the correlation between fluorescence yield and element concentration can be extracted, leading to actual trace element levels in tissue. We hope to prove the feasibility of monitoring elements in levels normally found in breast tissue, using this XRF technique. We plan to show results referring both to normal and neoplastic tissue, stating levels of as many trace elements as possible. We should also be able to present minimum detectable levels regarding every element investigated with this system, as well as have propositions for further optimising the performance of the technique. (author)

  6. Eyjafjallajokull volcanic ash concentrations determined from CALIOP and SEVIRI measurements (Invited)

    Prata, F.; Prata, A.

    2010-12-01

    During 14 April to 25 May 2010, Eyjfjoll volcano in Iceland, erupted a large amount of fine grained ash that rapidly spread across the north Atlantic and entered European airspace causing significant disruption to commercial aviation. Dispersion models and satellite data were used to identify the location of the Eyjafloll ash cloud, but due to lack of information on the eruption source parameters, quantitative estimates of the ash concentrations could not be made. By using multispectral, high frequency geosynchronous satellite measurements from the SEVIRI instrument, it is shown that quantitative estimates of the mass loadings (g m-2) can be made with accuracies of ±50% and with a detection limit of ~0.5 g m-2, every 15 minutes (night or day) and with a spatial resolution that varies from about 10--100 km2, depending on scan position. When the mass loadings are combined with coincident cloud thickness measurements from the Caliop lidar on board CALIPSO, ash concentrations can be derived. Here it is shown that ash concentrations in the dense parts of the dispersing Eyjfjoll ash cloud frequently exceeded 4 mg m-3 and that ash clouds with concentrations >2 mg m-3 covered large parts of European airspace on several occasions. Animated loops of SEVIRI ash mass loadings have been generated and a Google Earth applet designed to illustrate the geographic extent of the ash over Europe, and interactively interrogate the retrievals. Air-routes from European and US airports can also be added. These tools and the new satellite retrieval methodology may be combined with dispersion model results to provide Volcanic Ash Advisory Centres (VAACs) with better information for issuing volcanic ash advisories Google Earth visualization showing SEVIRI retrieved ash mass loadings and air routes from London to airports in Ireland, Scotland and continental Europe that cross the hazardous ash cloud.

  7. Plasma concentrations of blood coagulation factor VII measured by immunochemical and amidolytic methods

    Bladbjerg, E-M; Gram, J; Jespersen, J

    2000-01-01

    Ever since the coagulant activity of blood coagulation factor VII (FVII:C) was identified as a risk indicator of cardiac death, a large number of studies have measured FVII protein concentrations in plasma. FVII protein concentrations are either measured immunologically with an ELISA method (FVII......:Ag) or estimated with an amidolytic method (FVII:Am). We have investigated whether FVII:Am is a valuable alternative to FVII:Ag. FVII:Ag and FVII:Am were measured in 147 plasma samples from blood donors, patients on oral anticoagulant therapy, postmenopausal women on hormone replacement therapy, in...... after omitting the data from patients on oral anticoagulant therapy, with mean values of 113 U/ml for FVII:Ag and 110 U/ml for FVII:Am (p < 0.01). In a linear regression analysis, the intercept (alpha=-21.50) was different from zero (p < 0.0001) and the slope (beta=1.16) was different from 1.0 (p < 0...

  8. Measurements of radon concentration levels in drinking water at urban area of Curitiba, Brazil

    Current work presents the results of more than 100 measurements of 222Rn activity in drinking water collected at artesian bores at Curitiba region during the period of 2008 - 2009. The measurements were performed at the Laboratory of Applied Nuclear Physics of the Federal University of Technology in cooperation with the Nuclear Technology Development Center (CDTN) of Brazilian Nuclear Energy Committee (CNEN). Experimental setup was based on the Professional Radon Monitor (ALPHA GUARD) connected to specific kit of glass vessels Aqua KIT through the air pump. The equipment was adjusted with air flow of 0.5 L/min. The 222Rn concentration levels were detected and analyzed by the computer every 10 minutes using the software DataEXPERT by GENITRON Instruments. Collected average levels of 222Rn concentration were processed taking into account the volume of water sample and its temperature, atmospheric pressure and the total volume of the air in the vessels. Collected samples of water presented the average 222Rn activity about 57.70 Bq/L which is almost 5 times more than maximum level of 11.1 Bq/L recommended by the USEPA (United States Environmental Protection Agency). It has to be noted that many artesian drillings presented the radon activity in the range of 100 - 200 Bq/L. Further measurements are planned to be performed at other regions of Parana State and will involve the mineral water sources, explored artesian drillings as well as soil samples. (author)''

  9. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    Jaco H. Visser

    2012-03-01

    Full Text Available The accumulating-type (or integrating-type NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s, the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed.

  10. Measurement of radon, radon daughters and thoron concentrations by multi-detector devices. No. E/12

    There is a growing interest in collection of data concerning human exposures to naturally occurring alpha-emitting radionuclides (e.g. in mines, dwellings, building materials, industrial wastes, coal fuel cycle, water supply, soil, plants, etc.). Most of such studies are incomplete for the following reasons: in radon measurements the contribution of thoron is generally neglected, the determination of equilibrium factor is complicated or not possible at all, short- and long-term concentration fluctuations cause difficulties in obtaining representative mean values, the plate-out effect is generally not taken into account. A variety of simple methods were studied that could be used to overcome some of these difficulties by using cups equipped with two or more alpha-sensitive nuclear track detectors. A theoretical foundation of the quantitative measurements with such devices is presented. Experimental data are reported on radon, radon daughters and thoron concentrations measured by multi-detector devices in cave soil gas and in air of Hungarian dwellings. (author)

  11. Measurements of radon concentration in soil gas by CR-39 detectors

    A miniature diffusion chamber with a 25x4x0.5 mm CR-39 track etch detector (Pershore Moulding Ltd.), mounted on the 1.1 m long pole has been developed for radon gas measurements at 1 meter depth in the soil. For chemically etched CR-39 (7h, 70 deg. C NaOH) and automatic track analysis the lowest detection limit of the chamber was found to be 0.5 MBq h m-3 and the useful exposure range from 2 to 20 MBq h m-3. The typical exposure time in the soil is between 2 to 14 days. The chamber was tested against the active AlphaGUARD PQ-2000 (Genitron Instruments GmbH) probe. The test yielded consistent results for soils with typical values of permeability and which are not saturated with water. The pilot measurements of radon gas in soil conducted with the miniature diffusion chambers around 48 buildings in Krakow and Silesia regions yielded an average radon concentration of 13 kBq m-3. The chambers are to be applied to measure radon concentration in soil before constructing new houses in order to avoid high radon risk areas

  12. The Molecular Bronchoscope: A Tool for Measurement of Spatially Dependent CO2 Concentrations in the Lungs.

    Ciaffoni, Luca; Couper, John H; Richmond, Graham; Hancock, Gus; Ritchie, Grant A D

    2016-09-01

    Respiratory physicians use bronchoscopy for visual assessment of the lungs' topography and collecting tissue samples for external analysis. We propose a novel bronchoscope tool that would enable spatially dependent measurements of the functioning of the lungs by determining local concentrations of carbon dioxide, which will be produced by healthy parts of the lung at rates that are higher than from portions where gas exchange is impaired. The gas analyzer is based on a compact laser absorption spectrometer making use of fiber optics for delivery and return of low intensity diode laser radiation to and from the measurement chamber at the distal end of a flexible conduit. The appropriate optical wavelength was chosen such that light is selectively absorbed only by gaseous CO2. The optical absorption takes place over a short path (8.8 mm) within a rigid, 12 mm long, perforated probe tip. Wavelength modulation spectroscopy was adopted as the analytical technique to reduce the noise on the optical signal and yield measurements of relative CO2 concentration every 180 ms with a precision as low as 600 part-per-million by volume. The primary objective of such a device is to see if additional spatial information about the lungs functionality can be gathered, which will complement visual observation. PMID:27487178

  13. Laser Induced Fluorescence For Measurement Of Lignin Concentrations In Pulping Liquors

    Horvath, J. J.; Semerjian, H. G.; Biasca, K. L.; Attala, R.

    1988-11-01

    Laser excited fluorescence of pulping liquors was investigated for use in the pulp and paper industry for process measurement and control applications. Liquors from both mill and laboratory cooks were studied. A Nd-YAG pumped dye laser was used to generate the excitation wavelength of 280 nm; measurements were also performed using a commercially available fluorometer. Measurements on mill pulping liquors gave strong signals and showed changes in the fluorescence intensity during the cook. Absorption spectra of diluted mill liquor samples showed large changes during the cook. Samples from well controlled and characterized laboratory cooks showed fluorescence to be linear with concentration over two decades with an upper limit of approximately 1000 ppm dissolved lignin. At the end of these cooks a possible chemical change was indicated by an increase in the observed fluorescence intensity. Results indicate that lignin concentrations in pulping liquors can be accurately determined with fluorescence in the linear optical region over a greater dynamic range than absorption spectroscopy. Laser induced fluorescence may also provide an indication of chemical changes occurring in the lignin structure during a cook.

  14. Size segregated aerosol mass concentration measurements over the Arabian Sea during ICARB

    Vijayakumar S Nair; K Krishna Moorthy; S Suresh Babu; K Narasimhulu; L Siva Sankara Reddy; R Ramakrishna Reddy; K Rama Gopal; V Sreekanth; B L Madhavan; K Niranjan

    2008-07-01

    Mass concentration and mass size distribution of total (composite) aerosols near the surface are essential inputs needed in developing aerosol models for radiative forcing estimation as well as to infer the environment and air quality. Using extensive measurements onboard the oceanographic research vessel, Sagar Kanya, during its cruise SK223B in the second phase of the ocean segment of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB), the spatial distribution of the mass concentration and mass size distribution of near-surface aerosols are examined for the first time over the entire Arabian Sea, going as far as 58°E and 22°N, within a span of 26 days. In general, the mass concentrations () were found to be low with the mean value for the entire Arabian Sea being 16.7 ± 7 g m−3; almost 1/2 of the values reported in some of the earlier campaigns. Coarse mode aerosols contributed, on an average, 58% to the total mass, even though at a few pockets accumulation mode contribution dominated. Spatially, significant variations were observed over central and northern Arabian Sea as well as close to the west coast of India. In central Arabian Sea, even though the was quite low, contribution of accumulation aerosols to the total mass concentration was greater than 50%. Effective radius, a parameter important in determining scattering properties of aerosol size distribution, varied between 0.07 and 0.4 m with a mean value of 0.2 m. Number size distributions, deduced from the mass size distributions, were approximated to inverse power-law form and the size indices () were estimated. It was found to vary in the range 3.9 to 4.2 with a mean value of 4.0 for the entire oceanic region. Extinction coefficients, estimated using the number-size distributions, were well-correlated with the accumulation mode mass concentration with a correlation coefficient of 0.82.

  15. Effects of field storage method on E. coli concentrations measured in storm water runoff.

    Harmel, Daren; Wagner, Kevin; Martin, Emily; Smith, Doug; Wanjugi, Pauline; Gentry, Terry; Gregory, Lucas; Hendon, Tina

    2016-03-01

    Storm water runoff is increasingly assessed for fecal indicator organisms (e.g., Escherichia coli, E. coli) and its impact on contact recreation. Concurrently, use of autosamplers along with logistic, economic, technical, and personnel barriers is challenging conventional protocols for sample holding times and storage conditions in the field. A common holding time limit for E. coli is 8 h with a 10 °C storage temperature, but several research studies support longer hold time thresholds. The use of autosamplers to collect E. coli water samples has received little field research attention; thus, this study was implemented to compare refrigerated and unrefrigerated autosamplers and evaluate potential E. coli concentration differences due to field storage temperature (storms with holding times ≤24 h) and due to field storage time and temperature (storms >24 h). Data from 85 runoff events on four diverse watersheds showed that field storage times and temperatures had minor effects on mean and median E. coli concentrations. Graphs and error values did, however, indicate a weak tendency for higher concentrations in the refrigerated samplers, but it is unknown to what extent differing die-off and/or regrowth rates, heterogeneity in concentrations within samples, and laboratory analysis uncertainty contributed to the results. The minimal differences in measured E. coli concentrations cast doubt on the need for utilizing the rigid conventional protocols for field holding time and storage temperature. This is not to say that proper quality assurance and quality control is not important but to emphasize the need to consider the balance between data quality and practical constraints related to logistics, funding, travel time, and autosampler use in storm water studies. PMID:26884357

  16. Rapid Measurement of Radon Daughters Concentrations in Allouga Uranium Exploration Gallery, Sinai, Egypt

    Radon gas and radon daughters concentrations were measured by active techniques using two instruments: EDA( RDA-200) and Tri-Met-372. The measurements were carried out during the month of June in a tunnel network at Allouga area, west central Sinai. In the ventilated sector (16 stations), the average tunnel air temperature was 24.4 ± 2.2 degree c and average relative humidity 38%. The radon gas concentrations using calibrated Lucas cell ranged 3.3-22.8 pCi/1 with an average of 11.9 pCi/1. The radon daughters concentration using Tri-Met-372: Kusnetz method range 0.01 -0.36 Wl and average 0.1 WL and Modified Tsivoglou method range 0.01-0.38 WL and average 0.1 WL. The results of the EDA(RDA-200) are :Rolle method range 0.01-0.29 WL and average 0.13 WL, Kusnetz method range 0.01-0.31 WL and average 0.12 WL, and Tsivoglou method range 0.02-0.41 Wl and average 0.15 WL. These reported averages estimated by the different techniques are consistent within the statistical errors. In the non-ventilated sector (12 stations), the average tunnel air temperature was 22.2±0.4 degree and average relative humidity 70%. The radon gas concentrations range 313-1348 pCi/1 and average 786 pCi/1. The radon daughters concentrations using Tri-Met-372 :Kusnetz method range 1.4 -13.88 WL and average 7.21 WL. The results of the EDA (RDA-200) are : Rolle method range 1.04- 12.9 Wl and average 6.910 WL. Kusnetz method range 0.98 - 12.24 WL and average 6.92 WL, and Tsivoglou method range 0.92-12.09 WL and average 6.84 WL. The reported averages by the different methods are consistent within the statistical errors. It is clear that the non-ventilated sector presents occupational working hazard in these tunnels, and strict radiation protection measures should be undertaken such as industrial ventilation

  17. Laser Sounder for Global Measurement of CO2 Concentrations in the Troposphere from Space: Progress

    Abshire, J. B.; Krainak, M.; Riris, H. J.; Sun, X.; Riris, H.; Andrews, A. E.; Collatz, J.

    2004-01-01

    We describe progress toward developing a laser-based technique for the remote measurement of the tropospheric CO2 concentrations from orbit. Our goal is to demonstrate a lidar technique and instrument technology that will permit measurements of the CO2 column abundance in the lower troposphere from aircraft at the few ppm level, with a capability of scaling to permit global CO2 measurements from orbit. Accurate measurements of the tropospheric CO2 mixing ratio from space are challenging due to the many potential error sources. These include possible interference from other trace gas species, the effects of temperature, clouds, aerosols & turbulence in the path, changes in surface reflectivity, and variability in dry air density caused by changes in atmospheric pressure, water vapor and topographic height. Some potential instrumental errors include frequency drifts in the transmitter, small transmission and sensitivity drifts in the instrument. High signal-to-noise ratios and measurement stability are needed for mixing ratio estimates at the few ppm level. We have been developing a laser sounder approach as a candidate for a future space mission. It utilizes multiple different laser transmitters to permit simultaneous measurement of CO2 and O2 extinction, and aerosol backscatter in the same measurement path. It directs the narrow co-aligned laser beams from the instrument's fiber lasers toward nadir, and measures the energy of the strong laser echoes reflected from the Earth's land and water surfaces. During the measurement its narrow linewidth lasers are rapidly tuned on- and off- selected CO2 line near 1572 nm and an O2 absorption line near 770 nm. The receiver measures the energies of the laser echoes from the surface and any clouds and aerosols in the path with photon counting detectors. Ratioing the on- to off-line echo pulse energies for each gas permits the column extinction and column densities of CO2 and O2 to be estimated simultaneously via the

  18. Suspended matter concentrations in coastal waters: Methodological improvements to quantify individual measurement uncertainty

    Röttgers, Rüdiger; Heymann, Kerstin; Krasemann, Hajo

    2014-12-01

    Measurements of total suspended matter (TSM) concentration and the discrimination of the particulate inorganic (PIM) and organic matter fraction by the loss on ignition methods are susceptible to significant and contradictory bias errors by: (a) retention of sea salt in the filter (despite washing with deionized water), and (b) filter material loss during washing and combustion procedures. Several methodological procedures are described to avoid or correct errors associated with these biases but no analysis of the final uncertainty for the overall mass concentration determination has yet been performed. Typically, the exact values of these errors are unknown and can only be estimated. Measurements were performed in coastal and estuarine waters of the German Bight that allowed the individual error for each sample to be determined with respect to a systematic mass offset. This was achieved by using different volumes of the sample and analyzing the mass over volume relationship by linear regression. The results showed that the variation in the mass offset is much larger than expected (mean mass offset: 0.85 ± 0.84 mg, range: -2.4 - 7.5 mg) and that it often leads to rather large relative errors even when TSM concentrations were high. Similarly large variations were found for the mass offset for PIM measurements. Correction with a mean offset determined with procedural control filters reduced the maximum error to estuarine waters. It should be possible to use the approach in oceanic or fresh water environments as well. The possibility of individual quality control will allow mass-specific optical properties to be determined with better resolved uncertainties and, hence, lower statistical variability, greatly improving our capability to model inherent optical properties of natural particles and its natural variability, e.g. dependence on particle size and the complex refractive index.

  19. Quantitative Measurement of Soot Concentration by Two-Wavelength Correction of Laser-Induced Incandescence Signals

    Jung, J. S. [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    1997-05-01

    To quantify the L II signals from soot particle of flames in diesel engine cylinder, a new method has been proposed for correcting L II signal attenuated by soot particles between the measuring point and the detector. It has been verified by an experiment on a laminar jet ethylene-air diffusion flame. Being proportional to the attenuation, the ratio of L II signal at two different detection wavelengths can be used to correct the measured L II signal and obtain the unattenuated L II signal, from which the soot volume fraction in the flame can be estimated. Both the 1064-nm and frequency-doubled 532-nm beams from the Nd : YAG laser are used. Single-shot, one-dimensional(1-D) line images are recorded on the intensified CCD camera, with the rectangular-profile laser beam using 1-mm-diameter pinhole. Two broadband optical interference filters having the center wavelengths of 647 nm and 400nm respectively and a bandwidth of 10 nm are used. This two wavelength correction has been applied to the ethylene-air coannular laminar diffusion flame, previously studied on soot formation by the laser extinction method in this laboratory. The results by the L II measurement technique and the conventional laser extinction method at the height of 40 nm above the jet exit agreed well with each other except around outside of the peaks of soot concentration, where the soot concentration was relatively high and resulting attenuation of the L II signal was large. The radial profile shape of soot concentration was not changed a lot, but the absolute value of the soot volume fraction around outside edge changed from 4 ppm to 6.5 ppm at r=2.8 mm after correction. This means that the attenuation of L II signal was approximately 40% at this point, which is higher than the average attenuation rate of this flame, 10 {approx} 15%. (author). 15 refs., 8 figs.

  20. Radon concentration as an indicator of the indoor air quality: development of an efficient measurement method

    Document available in abstract form only. Full text of publication follows: Energy conservation regulation could lead to a reduction of the air exchange rate and also a degradation of the indoor air quality. Present methods for the estimating the indoor air quality can only be implemented with limitations. This paper presents a method that allows the estimation of the indoor air quality under normal conditions by using natural radon as an indicator. With mathematical models, the progression of the air exchange rate is estimated by using the radon concentration. Furthermore, the progression of individual air pollutants is estimated. Through series of experiments in a measurement chamber, the modelling could be verified. (author)

  1. DNA copy number concentration measured by digital and droplet digital quantitative PCR using certified reference materials

    CORBISIER Philippe; Pinheiro, Leonardo; Mazoua, Stephane; KORTEKAAS Anna Maria; CHUNG PUI YAN JENNY; GERGANOVA TSVETELINA IVANOVA; Roebben, Gert; Emons, Hendrik; Emslie, K

    2015-01-01

    The value assignment for properties of six certified reference materials (ERM-AD623a–f), each containing a plasmid DNA solution ranging from 1 million to 10 copies per μL, by using digital PCR (dPCR) with the BioMark™ HD System (Fluidigm) has been verified by applying droplet digital PCR (ddPCR) using the QX100 system (Bio-Rad). One of the critical factors in the measurement of copy number concentrations by digital PCR is the partition volume. Therefore, we determined the average droplet volu...

  2. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    Visser, Jaco H.; Ralf Moos; David J. Kubinski; Isabella Marr; Gregor Beulertz; Andrea Groß

    2012-01-01

    The accumulating-type (or integrating-type) NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s), the integrating sensor is well suited to reliably detect low levels of NOx. Experimental resul...

  3. Photonic reagents for concentration measurement of flu-orescent proteins with overlapping spectra.

    Goun, Alexei; Bondar, Denys I; Er, Ali O; Quine, Zachary; Rabitz, Herschel A

    2016-01-01

    By exploiting photonic reagents (i.e., coherent control by shaped laser pulses), we employ Optimal Dynamic Discrimination (ODD) as a novel means for quantitatively characterizing mixtures of fluorescent proteins with a large spectral overlap. To illustrate ODD, we simultaneously measured concentrations of in vitro mixtures of Enhanced Blue Fluorescent Protein (EBFP) and Enhanced Cyan Fluorescent Protein (ECFP). Building on this foundational study, the ultimate goal is to exploit the capabilities of ODD for parallel monitoring of genetic and protein circuits by suppressing the spectral cross-talk among multiple fluorescent reporters. PMID:27181496

  4. Optoelectronic system to measure the concentration and turbidity of suspended solids in the water

    The selection of the site where a nuclear power plant is to be built requires intensive study of the environmental conditions. This work presents the results reached on the development of a measurement system of suspended solids based on turbidity characteristics of the water. The system consists of an optical transducer composed of an emitter and a detector of infrared light, both solid state type, whose electrical signal is electronically treated. The equipment was calibrated and certified against turbidity and concentration standards in laboratory use. The obtained results indicate the reliability of the experimental method. The utilization of the equipment at the shore reinforces its flexibility and commodity of use. (author)

  5. Photonic reagents for concentration measurement of flu-orescent proteins with overlapping spectra

    Goun, Alexei; Bondar, Denys I.; Er, Ali O.; Quine, Zachary; Rabitz, Herschel A.

    2016-05-01

    By exploiting photonic reagents (i.e., coherent control by shaped laser pulses), we employ Optimal Dynamic Discrimination (ODD) as a novel means for quantitatively characterizing mixtures of fluorescent proteins with a large spectral overlap. To illustrate ODD, we simultaneously measured concentrations of in vitro mixtures of Enhanced Blue Fluorescent Protein (EBFP) and Enhanced Cyan Fluorescent Protein (ECFP). Building on this foundational study, the ultimate goal is to exploit the capabilities of ODD for parallel monitoring of genetic and protein circuits by suppressing the spectral cross-talk among multiple fluorescent reporters.

  6. Enhancement of sub-barrier fusion cross section in the weakly bound neutron system, 11Be + 10Be

    The sub-barrier fusion cross section for the weakly bound neutron system, 11Be + 10Be is discussed in the framework of the coupled-reaction-channel approach for the valence neutron in 11Be and in connection with the molecular orbital formation. In the calculation we observed a big enhancement of the fusion process, due to very strong multi-step processes in the inelastic and transfer transitions of the active neutron, which lead to the formation of a covalent molecule, 10Be + n + 10Be. (author)

  7. A Microfluidic Long-Period Fiber Grating Sensor Platform for Chloride Ion Concentration Measurement

    Jian-Neng Wang

    2011-09-01

    Full Text Available Optical fiber sensors based on waveguide technology are promising and attractive in chemical, biotechnological, agronomy, and civil engineering applications. A microfluidic system equipped with a long-period fiber grating (LPFG capable of measuring chloride ion concentrations of several sample materials is presented. The LPFG-based microfluidic platform was shown to be effective in sensing very small quantities of samples and its transmitted light signal could easily be used as a measurand. The investigated sample materials included reverse osmosis (RO water, tap water, dilute aqueous sample of sea sand soaked in RO water, aqueous sample of sea sand soaked in RO water, dilute seawater, and seawater. By employing additionally a chloride ion-selective electrode sensor for the calibration of chloride-ion concentration, a useful correlation (R2 = 0.975 was found between the separately-measured chloride concentration and the light intensity transmitted through the LPFG at a wavelength of 1,550 nm. Experimental results show that the sensitivity of the LPFG sensor by light intensity interrogation was determined to be 5.0 × 10−6 mW/mg/L for chloride ion concentrations below 2,400 mg/L. The results obtained from the analysis of data variations in time-series measurements for all sample materials show that standard deviations of output power were relatively small and found in the range of 7.413 × 10−5–2.769 × 10−3 mW. In addition, a fairly small coefficients of variations were also obtained, which were in the range of 0.03%–1.29% and decreased with the decrease of chloride ion concentrations of sample materials. Moreover, the analysis of stability performance of the LPFG sensor indicated that the random walk coefficient decreased with the increase of the chloride ion concentration, illustrating that measurement stability using the microfluidic platform was capable of measuring transmitted optical power with accuracy in the range of −0

  8. Measurements of soot formation and hydroxyl concentration in near critical equivalence ratio premixed ethylene flame

    Inbody, Michael Andrew

    1993-01-01

    The testing and development of existing global and detailed chemical kinetic models for soot formation requires measurements of soot and radical concentrations in flames. A clearer understanding of soot particle inception relies upon the evaluation and refinement of these models in comparison with such measurements. We present measurements of soot formation and hydroxyl (OH) concentration in sequences of flat premixed atmospheric-pressure C2H4/O2/N2 flames and 80-torr C2H4/O2 flames for a unique range of equivalence ratios bracketting the critical equivalence ratio (phi(sub c)) and extending to more heavily sooting conditions. Soot volume fraction and number density profiles are measured using a laser scattering-extinction apparatus capable of resolving a 0.1 percent absorption. Hydroxyl number density profiles are measured using laser-induced fluorescence (LIF) with broadband detection. Temperature profiles are obtained from Rayleigh scattering measurements. The relative volume fraction and number density profiles of the richer sooting flames exhibit the expected trends in soot formation. In near-phi(sub c) visibility sooting flames, particle scattering and extinction are not detected, but an LIF signal due to polycyclic aromatic hydrocarbons (PAH's) can be detected upon excitation with an argon-ion laser. A linear correlation between the argon-ion LIF and the soot volume fraction implies a common mechanistic source for the growth of PAH's and soot particles. The peak OH number density in both the atmospheric and 80-torr flames declines with increasing equivalence ratio, but the profile shape remains unchanged in the transition to sooting, implying that the primary reaction pathways for OH remain unchanged over this transition. Chemical kinetic modeling is demonstrated by comparing predictions using two current reaction mechanisms with the atmospheric flame data. The measured and predicted OH number density profiles show good agreement. The predicted benzene

  9. Measurement of radon concentration in water by means of {alpha}, {gamma} spectrometry. Radon concentration in ground and spring water in Hiroshima Prefecture

    Shizuma, Kiyoshi [Hiroshima Univ. (Japan)

    1997-02-01

    Radon ({sup 222}Rn, T{sub 1/2}=3.8235{+-}0.0003d) is {alpha}-ray releasing nuclide, so that it can not be detected by {gamma}-ray measurement. But, the daughter nuclides {sup 214}Pb (T{sub 1/2}=26.8 min) and {sup 214}Bi (T{sub 1/2}=19.9 min) release {gamma}-ray, accordingly they are measured by Ge detector. Their radioactive equilibrium is kept in the closed vessel, because their half-lives are shorter than that of radon. We developed a measurement method of radon concentration by means of {gamma}-spectrometry. We applied this method to catch radon in the atmosphere by active carbon. The same principle can be applied to radon in water. Radon concentrations in the ground water were measured in 22 points in the Higashi-Hiroshima city and 82 points in the Hiroshima prefecture. The efficiencies of {gamma}-ray were determined. The radon concentration showed between 11 and 459 Bq/l and the average was 123 Bq/l. The high concentration of radon was distributed in the spring of granitic layer and higher concentration of radon were observed in the ground water of fault. (S.Y.)

  10. Crystallization in Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass under pressure

    Jiang, Jianzhong; Zhou, T.J.; Rasmussen, Helge Kildahl;

    2000-01-01

    The effect of pressure on the crystallization behavior of the bulk metallic glass-forming Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy with a wide supercooled liquid region has been investigated by in situ high-pressure and high-temperature x-ray powder diffraction measurements using synchrotron radiation....

  11. A survey of laser and selected optical systems for remote measurement of pollutant gas concentrations

    Grant, W. B.; Menzies, R. T.

    1983-01-01

    Applications of the Differential Absorption Lidar (DIAL) technique to the remote sensing of pollutant gases are surveyed. In the DIAl technique, the differential absorption of two laser beams reflected back to a receiver from a target determines the concentration of the gas being studied. The types of instruments available are considered in detail: dye lidar (to measure nitrogen dioxide, sulfur dioxide, and ozone); carbon dioxide laser (for ozone, ethylene, ammonia, and hydrazine), helium-neon laser (for methane); hydrogen fluoride laser (for HF); and tunable diode laser (for nitric oxide and carbon monoxide). DIAL instruments are compared with other optical remote sensors such as Fourier-transform infrared spectrometers, correlation spectrometers (COSPEC and GASPEC), and grating spectrometers; and criteria for the selection of an appropriate gas measuring system are suggested. Laser and other optical remote sensors are found to be cost effective in many cases, despite the fact that they are more costly than point-monitoring systems.

  12. Phasor Measurement Unit and Phasor Data Concentrator test with Real Time Digital Simulator

    Diakos, Konstantinos; Wu, Qiuwei; Nielsen, Arne Hejde

    2014-01-01

    The main focus of the electrical engineers nowadays, is to develop a smart grid that is able to monitor, evaluate and control the power system operation. The integration of Intelligent Electronic Devices (IED s) to the power network, is a strong indication of the inclination to lead the power...... network to a more reliable, secure and economic operation. The implementation of these devices though, demands the warranty of a secure operation and high-accuracy performance. This paper describes the procedure of establishing a PMU (Phasor Measurement Unit)–PDC (Phasor Data Concentrator) platform that...... is able to derive and communicate synchrophasor measurements of different parts of the power network and the development of tests, according to IEEE standards, that evaluate the performance of PMUs and PDCs. The tests are created by using a Real Time Digital Simulation (RTDS) system. The results...

  13. Carbon (EC/OC) concentrations as derived from routine PM measurements in the Netherlands

    Ten Brink, H.M.; Weijers, E.P. [ECN Biomass, Coal and Environmental Research, Petten (Netherlands); Van Arkel, F.T. [Netherlands Environmental Assessment Agency PBK, Den Haag (Netherlands); De Jonge, D. [GGD Amsterdam, Amsterdam (Netherlands)

    2009-12-15

    Filter samples, collected in the national BOP programme (Netherlands Research Program on Particulate Matter), were analysed for their carbon content. The average amount of carbon at the six measuring sites corresponded with a mass concentration of 5 {mu}g.m{sup -3} in PM10 and 4 {mu}g.m{sup -3} in PM2.5, showing that carbon is a major component of particulate matter (PM). An important problem was that a substantial part of the carbon was derived from volatile carbon that was adsorbed on the filters. The amount of adsorbed volatile carbon was estimated from the carbon found in unloaded filters. This report first describes the adsorption problem itself, because it is the main reason why a standard method for measuring carbon in PM is lacking. Subsequently is described how the actual amount of carbon in PM was estimated.

  14. Temperature and concentration dependent spin noise measurements in GaAs

    Roemer, Michael; Mueller, Georg; Huebner, Jens; Oestreich, Michael [Institute for Solid State Physics, Gottfried Wilhelm Leibniz University Hannover (Germany)

    2009-07-01

    Spin noise spectroscopy is an elegant method to access electron properties of direct gap semiconductors in thermal equilibrium while avoiding carrier heating and excitation of electron hole pairs. This technique is used to examine the electron spin lifetime and noise power in GaAs in dependence of electron doping concentration, sample temperature, and the probe laser wavelength. The measured power of the spin noise signal is used to extract information about the electron statistics and the position of the electrons in the conduction band. The measured data can be well explained using a model based on the change of the index of refraction due to the ever present thermal fluctuations of the electron spin.

  15. Measurements of local interfacial area concentration in two-phase bubbly flow

    The local interfacial characteristics of an air-water, bubbly upflow in a circular pipe has been investigated experimentally cased on the measurements of a miniature two-sensor resistivity probe. Radial profiles of interfacial area concentration (IAC), together with other structural parameters (void fraction, bubble frequency, bubble velocity and Sauter mean bubble diameter) were simultaneously measured at four axial positions with entrance length (L)-to-internal diameter (D) ratios of 30, 60, 90 and 120. The experiments were carried out under various fixed gas and liquid fluxes, with only the bubble size being changed at the flow entrance. It is found that the phase distribution ana IAC are very sensitive to the variation oi the bubble size and the bubble coalescence effects during the development of bubbly flow. This paper summarizes the experimental results on the associated local interfacial parameters and compares the present data with the existing models used in predicting the IAC. (author)

  16. Effect of whey protein concentrate on texture of fat-free desserts: sensory and instrumental measurements

    Márcia Cristina Teixeira Ribeiro Vidigal

    2012-06-01

    Full Text Available It is important to understand how changes in the product formulation can modify its characteristics. Thus, the objective of this study was to investigate the effect of whey protein concentrate (WPC on the texture of fat-free dairy desserts. The correlation between instrumental and sensory measurements was also investigated. Four formulations were prepared with different WPC concentrations (0, 1.5, 3.0, and 4.5 wt. (% and were evaluated using the texture profile analysis (TPA and rheology. Thickness was evaluated by nine trained panelists. Formulations containing WPC showed higher firmness, elasticity, chewiness, and gumminess and clearly differed from the control as indicated by principal component analysis (PCA. Flow behavior was characterized as time-dependent and pseudoplastic. Formulation with 4.5% WPC at 10 °C showed the highest thixotropic behavior. Experimental data were fitted to Herschel-Bulkley model. The addition of WPC contributed to the texture of the fat-free dairy dessert. The yield stress, apparent viscosity, and perceived thickness in the dairy desserts increased with WPC concentration. The presence of WPC promotes the formation of a stronger gel structure as a result of protein-protein interactions. The correlation between instrumental parameters and thickness provided practical results for food industries.

  17. {sup 10}Be/{sup 230}Th ratios as proxy for particle flux in the equatorial Pacific ocean

    Anderson, R.F.; Fleisher, M.Q. [LDEO of Columbia Univ. (United States); Kubik, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Particulate {sup 10}Be/{sup 230}Th ratios collected by sediment traps in the central equatorial Pacific Ocean exhibit a positive correlation with particle flux, but little or no correlation with particle composition. (author) 1 fig., 4 refs.

  18. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    Rondo, L.; Ehrhart, S.; Kürten, A.; Adamov, A.; Bianchi, F.; Breitenlechner, M.; Duplissy, J.; Franchin, A.; Dommen, J.; Donahue, N. M.; Dunne, E. M.; Flagan, R. C.; Hakala, J.; Hansel, A.; Keskinen, H.; Kim, J.; Jokinen, T.; Lehtipalo, K.; Leiminger, M.; Praplan, A.; Riccobono, F.; Rissanen, M. P.; Sarnela, N.; Schobesberger, S.; Simon, M.; Sipilä, M.; Smith, J. N.; Tomé, A.; Tröstl, J.; Tsagkogeorgas, G.; Vaattovaara, P.; Winkler, P. M.; Williamson, C.; Wimmer, D.; Baltensperger, U.; Kirkby, J.; Kulmala, M.; Petäjä, T.; Worsnop, D. R.; Curtius, J.

    2016-03-01

    Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4 cluster distribution compared to binary (H2SO4-H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self-contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit.

  19. A system for vertical profile measurements of sensible heat and chemical concentrations near the ground surface

    Hyppoenen, M.; Walden, J.A.

    1996-12-31

    The design, construction and measurements of a computer controlled system applicable to flux measurements of a scalar quantity by the gradient technique are described. Accuracy requirements for the measured variables which are used for flux calculations are considered, together with some practical aspects concerning data storage and control. The construction includes the hardware and the data acquisition, sample intake, and temperature measurement systems. The measurements comprise laboratory tests of the temperature probes and the hardware as well as field tests over wheat and grass land for temperature and wind speed and ozone (O{sub 3}), carbon dioxide (CO{sub 2}) and nitrous oxide (N{sub 2}O) concentration profiles. The hardware takes care of most of the operation and only the necessary part is done by the software. The data acquisition system is flexible, accepting the input of either digital and/or analog signals. It also controls the whole system, storing all the data in a single data file. The sample intake unit is designed to take continuous samples in to the monitors as well as grab samples into the canisters. Samples can be selected from one to four levels with no dead volumes in the sampling tubes. The temperature measurement system is constructed using a pair of temperature probes, Pt-100, which are connected to the same signal processing card, in order to remove the offset of the electronic components as well as the bias associated with single probes. This ensures the accuracy of the probes down to 0.005 deg C. According to the field measurements, the relative error limits for the sensible heat fluxes varied from 7 to 20 % in an unstable atmospheric situation. For the ozone flux, the error limits varied from 20 to 100 %, indicating a much poorer accuracy of the monitor compared to the temperature probes. (orig.) 16 refs.

  20. [Clinical research on improvement of glucose metabolic marker level by coffee drinking-validity of saliva caffeine concentration measurement].

    Okada, Tomoko; Kobayashi, Daisuke; Kono, Suminori; Shimazoe, Takao

    2010-05-01

    We measured both serum and saliva caffeine concentration using HPLC and assessed the correlation between them in volunteers with mild obesity. Significant correlation was shown between saliva and serum caffeine concentration. It may be necessary to measure caffeine metabolite concentration because its metabolites may also have an improving effect of glucose metabolism. In summary, we found that saliva caffeine concentration measurement was useful to assess caffeine intake level. Moreover, it will be helpful to know whether caffeine has an improving effect of glucose metabolism. PMID:20460869