Gallium (III)-metalloporphyrin grafted magnetite nanoparticles for fluoride removal from aqueous solutions

Fluoride is a critical micronutrient for human health and is usually ingested through food and drinking water. This technique has done in monitoring the concentration of fluoride in water complications at mining operation that it effects on the environment. Fe3O4 nanoparticles were synthesized by coprecipitation of Fe2+ and Fe3+ in an alkaline solution, their surface was then modified with 3-aminopropyltriethoxysilane and a Ga(III) porphyrin complex, Ga(TCPP)Cl2[TCPP: tetrakis (4-carboxyphenyl) porphyrin]. The morphology and physical properties of these modified magnetic nanoparticles were examined by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The batch experiments showed that the nanoparticles could be used to remove fluoride ions from aqueous solution, achieving an extraction efficiency in excess of 96% for an initial fluoride concentration of 10 mg/L. This was obtained at pH 5.5 using 50 mg of modified nanoparticles and a contact time of 30 min

Adhesion attenuation and enhancement in aqueous solutions

When two surfaces confine water layers between them at the nanoscale, the behaviour of these confined water molecules can deviate significantly from the behaviour of bulk water, and it could reflect on the adhesion of such surfaces. This study assesses the role of confined water layers on the adhesion of hydrophilic surfaces and how sensitive this adhesion is to the presence of contaminants. Our methodology used atomic force microscopy adhesion measurements, whereby an alumina-sputtered sphere-tipped cantilever was interacted versus a flat alumina single crystal. Testing was performed under immersed conditions using (i) water, (ii) water/dimethylformamide mixtures, (iii) water/ethanol mixtures, and (iv) water/formamide mixtures. These solutions were intended to assess the influence of dielectric constant, molecule size, and the number of hydrogen bonding opportunities available to molecules upon confinement between surfaces. It was found that dilute concentrations of ethanol and formamide decreased the adhesion. In contrast, the adhesion increased in the presence of dilute concentrations of dimethylformamide. The adhesion was attenuated by in excess of two orders of magnitude for high concentrations of the organic solutes

Poking fun at the surface: exploring touch-point overloading on the multi-touch tabletop with child users

In this paper a collaborative game for children is used to explore touch-point overloading on a multi-touch tabletop. Understanding the occurrence of new interactional limitations, such as the situation of touch-point overloading in a multi-touch interface, is highly relevant for interaction designers working with emerging technologies. The game was designed for the Microsoft Surface 1.0 and during gameplay the number of simultaneous touch-points required gradually increases to beyond the physical capacity of the users. Studies were carried out involving a total of 42 children (from 2 different age groups) playing in groups of between 5-7 and all interactions were logged. From quantitative analysis of the interactions occurring during the game and observations made we explore the impact of overloading and identify other salient findings. This paper also highlights the need for empirical evaluation of the physical and cognitive limitations of interaction with emerging technologies

A public health management model for acute chemical incidents in Wales

The price of industrial progress is the potential for exposure of an increasingly informed public to chemical hazards in the environment. Of particular concern are acute exposures to chemical incidents, where problematic health risk assessments have highlighted the lack of expertise and resources available to support public health professionals in Wales responsible for protecting the health of populations. A systematic literature review of chemical incident databases, public health surveillance systems and major chemical incidents worldwide was used to guide the development of the first active, multi-agency community-based public health surveillance system for acute chemical incidents to be undertaken in Europe. A total of 642 acute chemical incidents were reported in Wales from all sources over a three year period. Of the 270 incidents reported by the primary source, chemical spills were the most frequently reported type of incident (28%) and operational industrial sites the most common location (25%). Of the estimated 238,000 people exposed, 528 reported symptoms in a total of 57 incidents. A single chemical was implicated in 86% of the incidents. Shortfalls were identified in the current expertise and resources available to public health professionals in Wales, leading to the development of a public health management model for acute chemical incidents. Model development took place in the context of United Kingdom - wide initiatives and involved the conduct of structured interviews with 41 organisations with interests in the field. The model selected for Wales was implemented on 1 February 1997 and comprised three levels of operation: (a) accountability for the protection of public health vested in health authorities at the local level; (b) a subscription-based front-line advisory and support unit to those authorities; (c) and a centrally funded national co-ordinating centre to provide the necessary evidence-base through programmes of surveillance, training, and emergency planning