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This work consists of the detection and quantification of the concentration levels of radioactive gas radon-222 (222Rn) of natural origin, as well as the determination of the critical points and the estimation of the effective dose absorbed by the tourists and guides inside the Jumandy cavern in Napo, Ecuador. According to the feasibility map of uranium of Ecuador, the study area is located in one of the top-priority areas for obtaining uranium, suggesting possible radioactivity in this unstudied region. The measurements were carried out from July to October of 2017, in three different monitoring points inside the cavern. The average radon concentrations measured in the cavern exceeded the maximum recommended environmental level by a factor of 28, and the effective dose absorbed by the guides exceeded the recommended maximum by a f actor of 10. Meteorological parameters such as temperature and relative humidity have an impact on the 222Rn concentrations in different parts of the cave. [ABSTRACT FROM AUTHOR]

NGC 4945 is one of the nearest (D ≈ 3.8 Mpc; 1″ ≈ 19 pc) starburst galaxies. To investigate the structure, dynamics, and composition of the dense nuclear gas of this galaxy, ALMA band 3 (λ ≈ 3−4 mm) observations were carried out with ≈2″ resolution. Three HCN and two HCO+ isotopologues, CS, C3H2, SiO, HCO, and CH3C2H were measured. Spectral line imaging demonstrates the presence of a rotating nuclear disk of projected size 10″ × 2″ reaching out to a galactocentric radius of r ≈ 100 pc with position angle PA = 45° ± 2°, inclination i = 75° ± 2° and an unresolved bright central core of size ≲2″. The continuum source, representing mostly free-free radiation from star forming regions, is more compact than the nuclear disk by a linear factor of two but shows the same position angle and is centered 0.′′39 ± 0.′′14 northeast of the nuclear accretion disk defined by H2O maser emission. Near the systemic velocity but outside the nuclear disk, both HCN J = 1 → 0 and CS J = 2 → 1 delineate molecular arms of length ≳15″ (≳285 pc) on opposite sides of the dynamical center. These are connected by a (deprojected) ≈ 0.6 kpc sized molecular bridge, likely a dense gaseous bar seen almost ends-on, shifting gas from the front and back side into the nuclear disk. Modeling this nuclear disk located farther inside (r ≲100 pc) with tilted rings provides a good fit by inferring a coplanar outflow reaching a characteristic deprojected velocity of ≈50 km s−1. All our molecular lines, with the notable exception of CH3 C2H, show significant absorption near the systemic velocity (≈571 km s−1), within the range ≈500–660 km s−1. Apparently, only molecular transitions with low critical H2 density (ncrit ≲ 104 cm−3) do not show absorption. The velocity field of the nuclear disk, derived from CH3 C2H, provides evidence for rigid rotation in the inner few arcseconds and a dynamical mass of Mtot = (2.1 ± 0.2) × 108 M⊙ inside a galactocentric radius of 2.′′45 (≈45 pc), with a significantly flattened rotation curve farther out. Velocity integrated line intensity maps with most pronounced absorption show molecular peak positions up to ≈1.′′5 (≈30 pc) southwest of the continuum peak, presumably due to absorption, which appears to be most severe slightly northeast of the nuclear maser disk. A nitrogen isotope ratio of 14N/15N ≈ 200–450 is estimated. This range of values is much higher then previously reported on a tentative basis. Therefore, because 15N is less abundant than expected, the question for strong 15N enrichment by massive star ejecta in starbursts still remains to be settled. [ABSTRACT FROM AUTHOR]

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Abstract: This article reports a simple and reliable approach to the synthesis of Cu‐doped Au nanocages through the co‐deposition of Au and Cu on the surfaces (both outer and inner) of pre‐synthesized Au nanocages by reducing HAuCl4 and CuCl2 with ascorbic acid under alkaline conditions. By controlling the total amount of Au and Cu deposited and/or the molar ratio between these two metals, we were able to adjust the Cu content in the resultant Au nanocages. The localized surface plasmon resonance properties of the Cu‐doped Au nanocages resemble those of the conventional Au nanocages, with strong and tunable absorption in the near‐infrared region. When radioactive 64CuCl2 was used in combination with nonradioactive CuCl2 as a source to elemental Cu, we obtained 64Cu‐doped Au nanocages. The radioactive nanocages could serve as tracers for position emission tomography (PET) imaging, and they were found to accumulate effectively in both 4T1 and patient derived xenograft (PDX) tumor models due to the enhanced permeability and retention effect. Autoradiography analysis indicated a homogeneous intra‐tumoral distribution for these nanocages. Taken together, the 64Cu‐doped Au nanocages are promising for image‐guided cancer theranostics. [ABSTRACT FROM AUTHOR]

The design of radiation measurement systems includes a modelling phase which ascertains the best 3D geometry for a projected gauge. To simulate measured counts by a detector, the widely-used rigorous phenomenological model is used. However, this model does not consider possible source or/and detector movement during a measurement interval. Therefore, the phenomenological model has been successfully modified in order to consider such a displacement during the time sampling interval in dynamic experiments. To validate the proposed model, a simple radiation system was accurately implemented in the MCNP5 code. The experiments confirmed the accuracy of the proposed model. [ABSTRACT FROM AUTHOR]

A MELCOR model of Fukushima Daiichi Unit 1 accident was developed. The model is based on publicly available information, and the MELCOR input file is published as Electronic Supplementary data with this paper. In order to reproduce the measured containment pressure, it was necessary to model a leak from the reactor coolant system. Recirculation pump seal leak, starting 5 h after the earthquake, was assumed in this study. The reactor pressure vessel lower head was calculated to fail, and all fuel was discharged to the containment. Almost all of the radioactive noble gases and about 0.05% of the cesium inventory were released to the environment, according to this calculation. Calculated release rates from Units 1, 2, and 3 were compared with measured radiation dose rate in the plant area. [ABSTRACT FROM AUTHOR]

Nuclear technology has long been used as a nondestructive method to measure the density of hot-mix asphalt (HMA) during pavement construction. Due to nuclear technology's high costs and intense regulations associated with safety and security, several researchers have introduced and evaluated nonnuclear technologies for measurement purposes. However, no proven evidence has emerged that nonnuclear gauges can replace nuclear gauges when quality assurance (QA) is considered. Thus, this study developed a framework for an empirical process to improve nonnuclear gauge performance for use in QA and for improving the current quality control (QC) process. Data were collected by coring using a nuclear gauge and using a nonnuclear gauge from 13 HMA paving construction sites over 2 years. A new calibration method was developed for nonnuclear density gauges. The research results reveal that the proposed framework can improve the accuracy of nonnuclear gauges, which can be used for QC and QA of HMA pavement during construction. In addition, nonnuclear gauges showed significant cost savings compared to nuclear gauges from a life-cycle cost analysis. [ABSTRACT FROM AUTHOR]

Abstract: Concentrations of radioactive radon gas (222Rn) were measured using passive monitors based on LR115 solid state track detectors during June–July 2010 in indoor air of dwellings in the Nui Beo coal mining area, mostly in Cam Pha and Ha Long coastal towns, Quang Ninh province, in the North of Vietnam. Global results of 222Rn concentrations indoors varied from ≤6 to 145 Bq m−3 averaging 46 ± 26 Bq m−3 (n = 37), with a median value of 47 Bq m−3. This was similar to outdoor 222Rn concentrations in the region, averaging 43 ± 19 Bq m−3 (n = 10), with a median value of 44 Bq m−3. Indoor 222Rn concentrations in the coastal town dwellings only were in average lower although not significantly different from indoor 222Rn concentrations measured at the coal storage field near the harbor, 67 ± 4 Bq m−3 (n = 3). Furthermore, there was no significant difference in the average 222Rn concentration in indoor air measured in the coastal towns region and those at the touristic Tuan Chau Island located about 45 km south of the coal mine, in the Ha Long Bay. The indoor 222Rn concentration in a floating house at the Bai Tu Long Bay, and assumed as the best estimate of the baseline 222Rn in surface air, was 27 ± 3 Bq m−3 (n = 3). Indoor average concentration of 222Rn in dwellings at the Ha Noi city, inland and outside the coal mining area, was determined at 30 Bq m−3. These results suggest that 222Rn exhalation from the ground at the Nui Beo coal mining area may have contributed to generally increase 222Rn concentration in the surface air of that region up to 1.7 times above the baseline value measured at the Bai Tu Long Bay and Ha Noi. The average indoor concentration of 222Rn in Cam Pha–Ha Long area is about one-third of the value of the so-called Action Level set up by the US EPA of 148 Bq m−3. Results suggest that there is no significant public health risk from 222Rn exposure in the study region. [Copyright &y& Elsevier]

Changes in volumetric activity of Kr radioactive inert gas take place in the atmosphere: it has increased by around 50% during the past 15 years. The main source of such gas is the operation of nuclear power plants and spent nuclear fuel reprocessing plants. Kr as an inert gas spreads throughout the entire atmosphere and its ionizing radiation may result in changes of atmospheric electric phenomena. Therefore it is necessary to control Kr emission into the atmosphere. However, there is no effective method for this as inert gases, under normal conditions, can hardly be adsorbed in different adsorbents and stored in special containers for a long period of time. This paper tries to show the possibility of keeping Kr longer within the adsorbent by changing its aggregate state: gas is adsorbed into liquid adsorbent and desorption takes place from solid adsorbent. For this purpose, an epoxy resin is used which, after adding a special hardener at room temperature, turns into a solid material with density of around 1.2 × 10 kg m. As a result of sample blending with substances which contribute to better solubility of Kr, diffusion coefficient of this gas (i.e. desorption speed) changes within the adsorbent in the solid state. [ABSTRACT FROM AUTHOR]

Abstract: The National Metrology Institute of Japan (NMIJ) participated in the CCRI(II) Key-comparison of 85Kr activity measurement. The absolute internal gas-counting method was used, with a set of proportional counters of different length. The original 85Kr gas was diluted by a factor of 2×105 in order to achieve the suitable activity concentration for the proportional counters. A new dilution method was introduced, based on a large-volume balloon and gravimetric determination of the dilution volume with small uncertainties. [Copyright &y& Elsevier]

Abstract: An extensive study of GeV light-ion-induced multifragmentation and its possible interpretation in terms of a nuclear liquid–gas phase transition has been performed with the Indiana Silicon Sphere (ISiS) detector array. Measurements were performed with 5–15GeV/, , and beams incident on 197Au and 2–5GeV 3He incident on natAg and 197Au targets. Both the reaction dynamics and the subsequent decay of the heavy residues have been explored. The data provide evidence for a dramatic change in the reaction observables near an excitation energy of . In this region, fragment multiplicities and energy spectra indicate emission from an expanded/dilute source on a very short time scale (20–50fm/c). These properties, along with caloric curve and scaling-law behavior, yield a pattern that is consistent with a nuclear liquid–gas phase transition. [Copyright &y& Elsevier]

On-line gauges are used in many industries to measure characteristics of raw material destined for a production process. In the coal industry, which is the focus of interest in this paper, the traditional method for determining coal characteristics has been the assay of coal samples. This method requires a great deal of work on a day-to-day basis. It has the further drawback that there is generally a time lag of at least 1 day between sampling of the coal and obtaining numerical measures of its quality characteristics. An interesting recent development is that nuclear gauges, which are capable of producing estimates of coal quality in real time, are now available commercially. The present paper demonstrates how bootstrap methods can be used to obtain a confidence interval for gauge precision using gauge output data alone. No specially constructed reference values from a sampling and assay operation are required. As such, the method is potentially an attractive alternative to the methodology set out in ISO 15239. It is also shown how gauge calibration can be checked using gauge output and one set of reference samples obtained under normal operating conditions. The method, which again uses the bootstrap, involves the construction of a simultaneous confidence band for a calibration function that relates gauge values to reference values. [Copyright &y& Elsevier]

Discusses the use of nuclear gage on the field measurement of water cementitious material ratio. Development of a standard for the nuclear water-cement gage; Means of distinguishing the quality of a mixture; Investigation of alternate methods to calibrate the nuclear gage.

Surface neutron–gamma gauges are handy instruments to measure soil water contents and bulk densities of surface layers. Although available for some decades, their optimal use is still not well established. This study is a contribution to improve their use, mainly in relation to calibration, and of the effect of soil dry bulk density on soil water content measurements. [Copyright &y& Elsevier]

The article aims to determine the performance of a hot-cathode-ionization-gauge head with correcting electrode and shield tube, operated with an automated-pressure-compensating circuit in a synchrotron radiation environment. In order to execute the tests the authors applied beam line No. 5 (BL5) in the New SUBARU electron storage ring. The usefulness of the gauge system is compared to that of simple ionization gauges when placed under a synchrotron radiation environment.

Comments on the paper "Field Measurement of Water-Cementitious Ratio Using Nuclear Gage," previously published in the November-December 2003 issue of "ACI Materials Journal". Errors and variability produced by field tests; Overestimation of cement content when using a mixture containing limestone.