An Airborne Gamma-Ray Spectrometry Survey of Nuclear Sites in Belgium

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Investigation of Spatial and Temporal Aspects of Airborne Gamma Spectrometry: Final Report

A study has been conducted which demonstrates the reproducibility of Airborne Gamma-ray Spectrometry (AGS) and the effects of changes in survey parameters, particularly line spacing. This has involved analysis of new data collected from estuarine salt marsh and upland areas in West Cumbria and SW Scotland during three phases of field work, in which over 150000 spectra were recorded with a 16 litre NaI(Tl) detector. The shapes and inventories of radiometric features have been examined. It has been shown that features with dimensions that are large relative to the survey line spacing are very well reproduced with all line spacings, whereas smaller features show more variability. The AGS technique has been applied to measuring changes in the radiation environment over a range of time scales from a few days to several years using data collected during this and previous surveys of the area. Changes due to sedimentation and erosion of salt marshes, and hydrological transportation of upland activity have been observed

Methodology of Using an Integrated Averaging Technique and MAUT Method for Failure Mode and Effects Analysis

The conventional Failure Mode and Effects Analysis (FMEA) which is popularly used for prioritizing risk of failure modes of industrial products has limitations such as the inability of the technique to utilize imprecise ratings from experts. These limitations impact negatively on its effectiveness in prioritizing risk. This paper presents a technique that integrates Averaging technique with Multi Attribute Utility Theory method for Failure Mode and Effects Analysis. The objective is to develop an alternative tool that avoids the limitations of the conventional FMEA such that risk of failure mode is prioritized more efficiently. The suitability of the proposed approach is demonstrated with a case study of the rotor blades of an aircraft turbine. The results show that the proposed approach is more flexible and effective for practical application than the conventional FMEA

Body cell mass index in children: interpretation of total body potassium results

Body cell mass (BCM) is a valuable measure of functional nutritional status in children. As BCM is related to body size, it is essential that BCM is adjusted for stature when interpreting BCM data in children. Our aim was to examine the relationship between height and BCM in healthy children to determine the power by which height should be raised to adjust BCM for stature. This cross-sectional study calculated BCM by K-40 counting in 146 healthy children aged between 5 and 18 years. The relationship between BCM and height was explored using log-log regression. The present results demonstrate that the power by which height should be raised to adjust for BCM in females is 2.39 (SE 0.09) and for males is 2.92 (SE 0.10). A simplified sex-specific version of the index, BCM/height(2.5) for females and BCM/height(3) for males, was found to be statistically valid and numerically convenient. with the proportion of variation that could be attributed to height being less than 2 %. The present study shows that there is a difference in the relationship between height and BCM for males and females and that BCM can be adjusted in children using the BCM index of BCM/height(2.5) for females and BCM/height(3) for males

Measurement and modelling of moisture—electrical resistivity relationship of fine-grained unsaturated soils and electrical anisotropy

A methodology for developing resistivity-moisture content relationships of materials associated with a clayey landslide is presented. Key elements of the methodology include sample selection and preparation, laboratory measurement of resistivity with changing moisture content, and the derivation of models describing the relationship between resistivity and moisture content. Laboratory resistivity measurements show that the techniques utilised (samples and square array) have considerable potential as a means of electropetrophysical calibration of engineering soils and weak rock. Experimental electrical resistivity results show a hierarchy of values dependent on sample lithology, with silty clay exhibiting the lowest resistivities, followed by siltstones and sands, which return the highest resistivities. In addition, finer grained samples show a greater degree of anisotropy between measurement orientations than coarser grained samples. However, suitability of results in light of issues such as sample cracking and electrical conduction must be identified and accounted for if the results are to be accurately up-scaled to inverted model resistivity results. The existence of directional anisotropy makes model calibration curve selection more difficult due to variability in the range of measured laboratory resistances. The use of larger measurement array size means that experimental data will be more representative of bulk lithological properties. In addition, use of electrodes with a relatively high surface area (wide diameter) help maintain low contact resistances and repeat measurement error, relative to narrow electrodes. Variation exists between the fit of experimental data and petrophysical models. Model fit is best for clay-dominated samples but fits less well for sand-dominated samples. Waxman–Smits equation is appropriately applied in this investigation as all samples have considerable clay mineral content, as is shown in non-negligible CEC results. The incorporation of pressure plate suction measurements on samples, allows suction dissipation to be quantified and evaluated alongside moisture content and electrical resistivity

Measurement of H₂O₂ within living drosophila during aging using a ratiometric mass spectrometry probe targeted to the mitochondrial matrix

Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is central to mitochondrial oxidative damage and redox signaling, but its roles are poorly understood due to the difficulty of measuring mitochondrial H<sub>2</sub>O<sub>2</sub> in vivo. Here we report a ratiometric mass spectrometry probe approach to assess mitochondrial matrix H<sub>2</sub>O<sub>2</sub> levels in vivo. The probe, MitoB, comprises a triphenylphosphonium (TPP) cation driving its accumulation within mitochondria, conjugated to an arylboronic acid that reacts with H<sub>2</sub>O<sub>2</sub> to form a phenol, MitoP. Quantifying the MitoP/MitoB ratio by liquid chromatography-tandem mass spectrometry enabled measurement of a weighted average of mitochondrial H<sub>2</sub>O<sub>2</sub> that predominantly reports on thoracic muscle mitochondria within living flies. There was an increase in mitochondrial H<sub>2</sub>O<sub>2</sub> with age in flies, which was not coordinately altered by interventions that modulated life span. Our findings provide approaches to investigate mitochondrial ROS in vivo and suggest that while an increase in overall mitochondrial H<sub>2</sub>O<sub>2</sub> correlates with aging, it may not be causative