Browsing by Author "Gu Q"

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    Controlled Hydrolysis of TiO2 from HCl Digestion Liquors of Ilmenite
    (American Chemical Society, 2022-05-18) Haverkamp RG; Wallwork KS; Waterland MR; Gu Q; Kimpton JA
    Traditionally, industrial scale production of the TiO2 pigment is achieved by hydrolysis from H2SO4 solution or by hydrolysis of TiCl4. However, the H2SO4 route produces FeSO4 waste, which is problematic, and the TiCl4 route requires a high grade rutile feedstock or chemically upgraded ilmenite (FeTiO3). Here, we investigate a direct route from ilmenite to TiO2 using aqueous HCl. New Zealand ilmenite digested in 35 wt % HCl to achieve a solution containing typically 1.18 mol kg-1 Fe(aq)2+ and 1.14 mol kg-1 Ti(aq)4+ was hydrolyzed under reflux, after seed preparation in water, or with phosphoric or citric acid. The structure of the seed was determined by Raman spectroscopy and X-ray powder diffraction using pair distribution function analysis, the latter enabling the identification of short-range order in poorly crystalline materials. TiO2 hydrate was precipitated from HCl in either the anatase or the rutile structure. Unlike from H2SO4, the natural structure formed without the use of structure determining agents is rutile. However, seed preparation using 0.4 mol H3PO4 per mole of Ti (resulting in 0.35 wt% H3PO4 in the hydrate) results in anatase hydrate formation. Sodium citrate or citric acid addition also seed anatase hydrate. The mechanism for polymorph control may be kinetic rather than a structural template or surface adsorption. This process has the potential to be used for the commercial scale production of the TiO2 pigment. Anatase hydrate has the advantage that traces of iron may be more readily removed by washing than from rutile precipitate, making the HCl process from ilmenite feasible for pigment grade material.
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    Situation report (SITREP) visualization for effective management of disaster incidents in Sri Lanka
    (EnPress Publisher LLC, 2023-10-18) Tillekaratne HI; Wickramagamage P; Werellagama I; Rathnayake U; Siriwardana C; Bandara A; Madduma-Bandara CM; Bandara TWMTW; Abeynayaka A; Gu Q
    During and after any disaster, a situation report (SITREP) is prepared, based on the Daily Incident Updates (DIU), as an initial decision support information base. It is observed that the decision support system and best practices are not optimized through the available formal reporting on disaster incidents. The rapidly evolving situation, misunderstood terms, inaccurate data and delivery delays of DIU are challenges to the daily SITREP. Multiple stakeholders stipulated with different tasks should be properly understood for the SITREP to initiate relevant response tasks. To fill this research gap, this paper identifies the weaknesses of the current practice and discusses the upgrading of the incident-reporting process using a freely available software tool, enabling further visualization, and producing a comprehensive timely output to share among the stakeholders. In this case, “Power-BI” (a data visualization software) is used as a 360-degree view of useful metrics—in a single place, with real-time updates while being available on all devices for operational decision-making. When a dataset is transformed into several analytical reports and dashboards, it can be easily shared with the target users and action groups. This article analyzed two sources of data, namely the Disaster Management Center (DMC) and the National Disaster Relief Service Center (NDRSC) of Sri Lanka. Senior managers of disaster emergencies were interviewed and explored social media to develop a scheme of best practices for disaster reporting, starting from just before the occurrence, and following the unfolding sequence of the disasters. Using a variety of remotely acquired imageries, rapid mapping, grading, and delineating impacts of natural disasters, were made available to concerned users.