Renewing approaches to understanding the minerals and waters at alkaline waste sites

Highly alkaline (pH 9-12) waters can arise from a range of natural and anthropogenic processes. The latter include drainage waters from a range of globally significant anthropogenic by-products such as lime, cement and steel wastes, bauxite processing residue and combustion ashes. Such waste storage sites are often characterised by extreme geochemical conditions that can be hazardous to aquatic life, but are equally an increasing focus for resource recovery and carbon capture initiatives. The very high rates of mineral precipitation at these sites can give rise to the formation of transient minerals that are not currently well understood. As such our estimates of carbon budgets and understanding of trace metal dynamics at highly alkaline sites is currently limited. This thesis aimed to improve the basis for characterising hyperalkaline carbonate systems by (1) understanding the dominant carbonate fabrics found in secondary deposits and their formation processes, (2) identifying transient minerals forming at hyperalkaline sites, and (3) improving methods for characterising dissolved inorganic carbon and secondary mineral phases at high pH sites.Petrographic analysis showed distinctive shrubby carbonates forming in hyperalkaline (pH 9–12) and moderate conductivity (conductivity 425–3200μS) solutions at ambient temperature (12.5–13°C) at two disposal sites in the UK. Microfabrics in anthropogenic sites are comparable to travertines but lack the sub-surface facies and at extreme pH exhibit sparry crusts without clear equivalents in travertines. Despite the highly alkaline conditions, significant diatomaceous and cyanobacterial biofilms were reported growing in the presence of these carbonates, suggesting a bio-influence on their formation. This sedimentology of anthropogenic carbonates shows that calcite mineral formation is complex and not homogeneous or purely driven by thermodynamic processes.Whilst most of the secondary deposits at the study sites appear to be dominated by calcite, this study provides the first account internationally of ikaite (CaCO3.6H2O) crystallization within steel-slag leachate through novel field (Fourier Transform Infra-Red) and laboratory (X-Ray Diffraction) validation. This study suggests that ikaite is a secondary mineral with a primary phase being amorphous calcium carbonate (ACC). The ikaite forming in steel-slag leachate affected waters is incorporating large inventories of potentially harmful metals (e.g. lead and cadmium) which could be of environmental concern given ikaite is not thermally stable and could release a pulse of contamination in short duration warming events. The final component of the study develops a new protocol for assessing dissolved inorganic carbon (DIC) in alkaline waters via strontium carbonate precipitation. This method is compared to established methods for DIC using field and laboratory titration. The strontium method appears to perform much better than the existing methods and is likely to provide more robust estimates of alkalinity and saturation index of carbonate minerals.The combined findings provide an improved understanding of carbonate precipitation processes at highly alkaline sites which in turn should assist future research endeavours around mineral carbonation, trace metal dynamics and environmental remediation at these sites

An Autonomous and Adaptable Wireless Device for Flood Monitoring

Wireless devices can be used to monitor and record a broad range of phenomena. Their advantages include ease of installation and maintenance and considerable reduction in wiring costs. The addition of battery power and radio communication to such wireless devices can result in a completely The operating environment of monitoring systems is often hostile, due to temperature fluctuations, humidity, electromagnetic noise, and other interfering phenomena. The system should be able to adapt to changing conditions to maintain dependability in its operations This paper presents the case study of adapting a flood detection device to the environmental threat of submersion

P. Vindob. G. 26221 riconsiderato: Omero, Il. 1, 601-602; 609-610 con parafrasi

New edition of this papyrus text published some years before by H. Harrauer, “Codices Manuscripti” 1, 1975, 74-77. The fragmentary lines in fact come from the Iliad, not from the Odyssey, as the first editor believed

BOTDA Sensing Employing a Modified Brillouin Fiber Laser Probe Source

A theoretical and experimental study has been carried out on a tunable dual pump-probe optical source for distributed Brillouin optical time-domain analysis (BOTDA). The developed source exploits a modified Brillouin ring laser technology and is capable of a tuning range of ∼200 MHz without using phase-locked loop or optical sideband generation techniques, and exhibits a linewidth smaller than 2.5 MHz and ∼0.5 mW power. In BOTDA experiments, the proposed source has demonstrated to be an efficient solution enabling distributed sensing over 10 km single mode fiber with a spatial resolution of ∼4 m, and a strain and temperature resolutions of ∼10 μϵ and ∼0.5 °C respectively

Analysis of enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

In this work, we present an enhanced design for a Brillouin ring laser (BRL), which employs a double resonant cavity (DRC) with short fiber length, paired with a heterodyne-based wavelength-locking system, to be employed as a pump-probe source for Brillouin sensing. The enhanced source is compared to traditional long-cavity pump-probe source, showing a significantly lower relative intensity noise (~-145 dB/Hz in the whole 0\u2013800 MHz range), a narrow linewidth (10 kHz), and large tunability features, resulting in an effective pump-probe source in BOTDA systems, with an excellent pump-probe frequency stability (~200 Hz), which is uncommon for fiber lasers. The enhanced source showed an improved signal-to-noise ratio (SNR) of about 22 dB with respect to standard BRL schemes, resulting in an improved temperature/strain resolution in BOTDA applications up to 5.5 dB, with respect to previous high-noise BRL designs

Le conversioni silenti

The section explores the two nights lived by the protagonists of the \u201cI Promessi Sposi\u201d: the night during which Renzo crosses the Adda river and the night spent by Lucia in the Innominato's castle. The symmetry of the organization of the two episodes triggers some analytical and synthetical considerations (see the table with the synopsis of the two episodes): when searching for the meaning of the two episodes an hypothesis of a hidden meaning written between the lines arises, in contrast with the narration. An hypothesis that leads us to explore the mysticism of XVIIth century, in particular the \u201cIl cantico Spirituale\u201d by San Giovanni della Croce. This interpretation might cast a new light on the whole of Manzoni's novel

Analisi degli strumenti di morphing di ANSA per l'Ottimizzazione Aerodinamica

Questa tesi mostra la realizzazione di una procedura di ottimizzazione aerodinamica per lo spoiler della Ferrari 458 Italia. Obbiettivo dell'ottimizzazione è minimizzare la resistenza aerodinamica della vettura modificandone la geometria dello spoiler tramite gli strumenti di morphing di ANSA e simulandone l'aerodinamica tramite programmi di CFD