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Recycling electronic waste (WEEE) is a fundamental aspect of the circular economy. To develop technology and assess its economic aspects, the composition characterization of the waste items is crucial. Neutron-based analytical techniques, such as the INAA, in-beam NAA, and PGAA, are applicable to measure the elemental composition of WEEE. These techniques are bulk representative and offer simultaneous determination of the relevant elements without sample dissolution. This study explores the suitability of neutron-based elemental analysis methods for measuring common WEEE items, e.g., printed circuit boards and integrated circuits. Matrix effects mostly related to the thermal neutron self-shielding, were identified and successfully corrected, ensuring accurate mass fraction measurements. [ABSTRACT FROM AUTHOR]

Hódmezővásárhely–Gorzsa is a multi-period tell settlement in South Hungary in the centre of the Great Hungarian Plain, about 15 km southwest of the city of Hódmezővásárhely. The thickest section of the settlement belongs to the Late Neolithic Tisza Culture period. In total, 1061 macrolithic artefacts were unearthed, a quarter of which was polished, and three quarter of which were ground stone tools. Half of the ground stones were made of different types of sandstone, including (1) red-, (2) grey micaceous-, (3) calcareous-, (4) white meta sandstones, and (5) other sandstones and metasandstones were identified. The red sandstones are further categorised into four subgroups based on optical microscopy. This examination is the first systematic multi-analytical investigation (i.e. optical microscopy, whole-rock geochemistry and mineral chemistry), carried out on these ground stone tool types. The goal is to identify and precisely locate the raw material types, in which heavy minerals and the tourmaline mineral chemistry play the key role. To determine the provenance of each of these subgroups, samples were collected from seven geological localities (i.e. primary outcrops and secondary presences, such as river drainages or terraces) for a comparative study. Based on our results, the alluvium of the Maros River can be considered as a possible source for the ‘Red – 3’ type of Gorzsa, while the results for the rest red sandstone types (‘Red – 1’, ‘Red − 2’ and ‘Red – 4’) are inconclusive in terms of provenance. [ABSTRACT FROM AUTHOR]

The present work investigates the hydration heat of different cement composites by means of conduction calorimetry to optimize the composition of binder in the design of heavyweight concrete as biological shielding. For this purpose, Portland cement CEM I 42.5 R was replaced by a different portion of supplementary cementitious materials (blast furnace slag, metakaolin, silica fume/limestone) at 75%, 65%, 60%, 55%, and 50% levels to obtain low hydration heat lower than 250 j g−1. All ingredients were analyzed by energy dispersive X-ray fluorescence (EDXRF) and nuclear activation analysis (NAA) to assess the content of major elements and isotopes. A mixture of two high-density aggregates (barite and magnetite) was used to prepare three heavyweights concretes with compressive strength exceeding 45 MPa and bulk density ranging between 3400 and 3500 kg m−3. After a short period of volume expansion (up to 4 h), a slight shrinkage (max. 0.3°/°°) has been observed. Also, thermophysical properties (thermal conductivity, volumetric specific heat, thermal diffusivity) and other properties were determined. The results showed that aggregate content and not binder is the main factor influencing the engineering properties of heavyweight concretes. [ABSTRACT FROM AUTHOR]

High-pressure metamorphic (HPM) rocks (derived from igneous protoliths) and their metasomatised rinds from the island of Syros (Greece) were analysed for their B and Cl whole-rock abundances and their H2O content by prompt-gamma neutron-activation analysis (PGNAA) and for their Li and Be whole-rock abundances by ICP-OES. In the HPM rocks, B /Be and Cl /Be ratios correlate with H2O contents and appear to be controlled by extraction of B and Cl during dehydration and prograde metamorphism. In contrast, samples of the metasomatised rinds show no such correlation. B /Be ratios in the rinds are solely governed by the presence or absence of tourmaline, and Cl /Be ratios vary significantly, possibly related to fluid inclusions. Li/Be ratios do not correlate with H2O contents in the HPM rocks, which may in part be explained by a conservative behaviour of Li during dehydration. However, Li abundances exceed the vast majority of published values for Li abundances in fresh, altered, or differentiated oceanic igneous rocks and presumably result from metasomatic enrichment of Li. High Li concentrations and highly elevated Li/Be ratios in most metasomatised samples demonstrate an enrichment of Li in the Syros HP mélange during fluid infiltration. This study suggests that B and Cl abundances of HPM meta-igneous rocks can be used to trace prograde dehydration, while Li concentrations seem to be more sensitive for retrograde metasomatic processes in such lithologies. [ABSTRACT FROM AUTHOR]