SCIENTIFICALLY SUBSTANTIATED GUIDELINES FOR PHYSICO-MATHEMATICAL MODELLING OF LASER SURFACE-TREATMENT OF WEAR-RESISTANT IMPLANTS FOR HUMAN JOINT REPLACEMENTS

This paper presents the main results from a set of guidelines on the physico-mathematical modelling of laser surface-treatment of wear-resistant implants for human joint replacements. These guidelines contain synthesized and documented procedure, theoretical and practical recommendations, which are provided by researchers in the Nanomaterials Laboratory under the Institute of Fundamental Science and Innovative Technologies, Liepaja University. The present paper does not attempt to cover all aspects of physical and mathematical modelling, but draws together many key aspects concerning theoretical and practical difficulties, in the overcoming of what researchers of the Nanomaterials Laboratory, in particular, the authors of the present paper, have sufficient skills

MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF THE OLYMPIAS MINE TAILINGS, NE CHALKIDIKI, GREECE

Τα τέλματα της Ολυμπιάδας στην ΒΑ Χαλκιδική, αποτελούν τα κατάλοιπα του εμπλουτισμού του κοιτάσματος Pb-Zn-Au-Ag που εντοπίζεται στα ανθρακικά πετρώματα της Ενότητας Κερδυλίων. Στην παρούσα εργασία, η ορυκτολογική σύσταση των τελμάτων προσδιορίστηκε με τη χρήση περιθλασιμετρίας ακτίνων-Χ (XRD), ηλεκτρονικής μικροσκοπίας σάρωσης (SEM) και οπτικής μικροσκοπίας, ενώ επιπλέον πραγματοποιήθηκαν χημικές αναλύσεις και μετρήσεις pH. Τα αποτελέσματα έδειξαν πως τα τέλματα συνίστανται από σύνδρομα ορυκτά (χαλαζίας, ροδοχρωσίτης, ασβεστίτης, άστριοι, μαρμαρυγίες, καολινίτης και ακτινόλιθος) και σουλφίδια (σιδηροπυρίτης, αρσενοπυρίτης, σφαλερίτης, χαλκοπυρίτης και γαληνίτης), κάτι που δείχνει ότι υπάρχει σχέση με την ορυκτολογική σύσταση της μεταλλοφορίας και των 2089 μητρικών πετρωμάτων. Επίσης, τα τέλματα αποτελούνται από ίχνη οξειδίων Fe (μαγνητίτης, αιματίτης), οξείδια-υδροξείδια Fe (γκαιτίτης) και οξείδια Mn, συχνά εμπλουτισμένα σε Zn και Pb και σε ορισμένες περιπτώσεις Fe, Sb και As. Επιπλέον εντοπίστηκαν δευτερογενή θειικά άλατα (γύψος, ιαροσίτης) και επανθίσματα θειικών αλάτων (σιδηροεξαϋδρίτης, εξαϋδρίτης, αλοτριχίτης). Τα τέλματα της Ολυμπιάδας είναι γενικά μη οξειδωμένα, δημιουργώντας ένα αλκαλικό περιβάλλον. Παρόλα αυτά, λόγω μεταβολών στη σύσταση, σχηματίζονται ξεχωριστές φάσεις περιορισμένης έκτασης, όπως λεπτές στρώσεις και φακοί οξειδωμένου υλικού, οι οποίες δημιουργούν όξινο περιβάλλον. Από την άποψη της περιεκτικότητας σε πολύτιμα μέταλλα, τα τέλματα της Ολυμπιάδας είναι εμπλουτισμένα σε Au (έως 12 g/t) και Ag (έως 20 g/t).The Olympias tailings of NE Chalkidiki, Greece represent the mine wastes produced by the beneficiation of the Pb-Zn-Au-Ag ore deposit, which is hosted within the carbonate rocks of the Kerdylia Unit. In the present study X-Ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, chemical analyses and pH measurements were conducted to determine the tailings mineralogy and chemical composition. The results indicated that they consist of gangue (quartz, rhodochrosite, calcite, dolomite, feldspars, micas, kaolinite and actinolite) and sulfide minerals (pyrite, arsenopyrite, sphalerite, chalcopyrite and galena), reflecting the source ore and its host rock composition, accompanied by traces of Fe-oxides (magnetite, hematite), Fe oxyhydroxides (goethite) and Mn-oxides, often enriched in Zn and Pb and in some cases Fe, Sb and As. Secondary sulfates (gypsum, jarosite) and surface efflorescent salts (ferrohexahydrite, hexahydrite, halotrichite) have also been recognized. The Olympias tailings are generally unoxidized, generating an alkaline environment. However, variations in composition result in the formation of restricted separate phases, such as thin layers and lenses of oxidized material that generates an acidic environment. In terms of precious metals content, the Olympias tailings are enriched in Au (up to 12 g/t) and Ag (up to 20 g/t)

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries