127 research outputs found

    Effect of Fibre Type on Mechanical Properties of Nonwoven Reinforced TPU Composites

    Get PDF
    Nonwoven-reinforced composites were produced using both low modulus fibres (lyocell, polyethylene terephthalate, and polyamide) and high modulus aramid fibres (polyphenylene terephthalamide) in thermoplastic polyurethane (TPU) matrix. Preferentially oriented web preforms were prepared by carding and pre-needling before impregnating the nonwovens in a thermoplastic polyurethane resin matrix. Composites were prepared by compression moulding and mechanical properties were evaluated. Scanning Electron Microscopy was employed to study the fibre-to-matrix interface in the nonwoven-reinforced composites. It was found that nonwoven reinforcement provided a range of mechanical properties, mainly linked to fibre properties and orientation of fibres in the web, apparently unaffected by the mechanical properties of the web. Furthermore, all studies fibres were thoroughly embedded in the matrix

    HYDROGEOLOGICAL ASSESSMENT OF GROUNDWATER DEGRADATION AT THE EASTERN NESTOS RIVER DELTA, N.E. GREECE.

    Get PDF
    This paper deals with the hydrogeological study of the evolution of groundwater salinisation - degradation at the eastern Nestos River Delta. Relevant field works including in-situ measurements of groundwater level, pH, Specific Electrical Conductivity (SEC) and temperature took place in the years 2008 and 2009. Groundwater samples were also collected for chemical analysis at the Engineering Geology Laboratory of the Department of Civil Engineering of D.U.Th. (July of 2009). Important conclusions regarding the progress of the groundwater degradation at the study area were drawn based on the analysis of all the available data and the elaboration of the designed piezometric maps and the various maps showing the distribution of SEC, Chloride, SAR (Sodium Absorption Ratio) and Revelle coefficient values. Some managerial suggestions for the confrontation of the seawater intrusion regime of the study area are also included

    Development of multi-criteria decision support system (DSS) coupled with GIS for identifying optimal locations for soil aquifer treatment (SAT) facilities

    Get PDF
    Η διαχείριση του εμπλουτισμού των υδροφορέων αποτελεί μια ευρέως διαδομένη τεχνική, ιδιαίτερα σε υδρολογικά ευαίσθητες περιοχές, όπως αυτές της Μεσογειακής Λεκάνης, όπου οι υδατικοί πόροι είναι περιορισμένοι. Η επιλογή της χωροθέτησης έργων τεχνητού εμπλουτισμού (Τ.Ε.) αποτελεί μια πολύπλοκη διαδικασία το αποτέλεσμα της οποίας καθορίζει εν πολλοίς και την ίδια την αποτελεσματικότητα του έργου. Η εν λόγω διαδικασία περιπλέκεται εντονότερα όταν πρόκειται για τη χρηση νερών εμπλουτιμού υποβαθμισμένης ποιότητας. Βασικός στόχος της παρούσας εργασίας είναι η παρουσίαση ενός πρόδρομου εργαλείου πολυ-κριτιριακού Συστήματος Λήψης Αποφάσεων, το οποίο ενσωματώνει σε μια δυναμική πλατφόρμα: τόσο τις τεχνικές του Τ.Ε. όσο και τα γεωγραφικά χαρακτηριστικά που καθορίζουν την αποτελεσματικότητα του έργου. Το προτεινόμενο σύστημα αποτελεί προχωρημένο εργαλείο σύζευξης Συστημάτων Λήψης Αποφάσεων και Γεωγραφικών Πληροφοριών ικανό να αξιολογεί κρίσιμα ζητήματα που αφορούν σε έργα Τ.Ε. –γεωλογικά, υδρογεωλογικά, κλιματολογικά, νομικά, κοινωνικά, οικονομμικά κ.α. – με ιδιαίτερη έμφαση σε συστήματα Επεξεργασίας-Εδάφους- Υδροφόρου. Το συγκεκριμένο εργαλείο πρόκειται να ενσωματωθεί στο λογισμικό ArcGIS, σε περιβάλλον φιλικό προς το χρήστη, όπου η προβολή και επεξεργασία χωρικών δεδομένων μπορεί να πραγματοποιηθεί με τη χρήση Arc tools.Managed Aquifer Recharge is a wide-spread well-established groundwater engineering method which is largely seen as an alternative potential major source for water and this conclusion becomes even more pronounced in semi-arid and/or arid areas, such as the Mediterranean Basin. The process of site selection for the installation of a MAR facility is of paramount importance for the feasibility and effectiveness of the project itself, especially when the facility will include the use of waters of impaired quality as a recharge source. The main objective of this study is to present the developed framework of a multicriteria Decision Support System (DSS) that integrates within a dynamic platform: the main groundwater engineering parameters associated with MAR applications together with the general geographical features which determine the effectiveness of such a project. The proposed system will provide an advanced coupled DSS-GIS tool capable of handling local MAR-related issues -such as hydrogeology, topography, soil, climate etc., and spatially distributed variables -such as societal, economic, administrative, legislative etc., with special reference to Soil-Aquifer- Treatment technologies. The new SAT-selection tool in question is integrated in ArcGIS software -within a user friendly environment- where data can be processed and displayed using Arc tools for spatial analysis

    Getting shops to voluntarily stop selling cheap, strong beers and ciders: a time-series analysis evaluating impacts on alcohol availability and purchasing.

    Get PDF
    BACKGROUND: 'Reducing the Strength' (RtS) is a public health initiative encouraging retailers to voluntarily stop selling cheap, strong beers/ciders (≥6.5% alcohol by volume). This study evaluates the impact of RtS initiatives on alcohol availability and purchasing in three English counties with a combined population of 3.62 million people. METHODS: We used a multiple baseline time-series design to examine retail data over 29 months from a supermarket chain that experienced a two-wave, area-based role out of RtS: initially 54 stores (W1), then another 77 stores (W2). We measured impacts on units of alcohol sold (primary outcome: beers/ciders; secondary outcome: all alcoholic products), economic impacts on alcohol sales and substitution effects. RESULTS: We observed a non-significant W1 increase (+3.7%, 95% CI: -11.2, 21.0) and W2 decrease (-6.8%, 95% CI: -20.5, 9.4) in the primary outcome. We observed a significant W2 decrease in units sold across all alcohol products (-10.5%, 95% CI: -19.2, -0.9). The direction of effect between waves was inconsistent for all outcomes, including alcohol sales, with no evidence of substitution effects. CONCLUSIONS: In the UK, voluntary RtS initiatives appear to have little or no impact on reducing alcohol availability and purchase from the broader population of supermarket customers

    Investigating associations between the built environment and physical activity among older people in 20 UK towns.

    Get PDF
    BACKGROUND: Policy initiatives such as WHO Age Friendly Cities recognise the importance of the urban environment for improving health of older people, who have both low physical activity (PA) levels and greater dependence on local neighbourhoods. Previous research in this age group is limited and rarely uses objective measures of either PA or the environment. METHODS: We investigated the association between objectively measured PA (Actigraph GT3x accelerometers) and multiple dimensions of the built environment, using a cross-sectional multilevel linear regression analysis. Exposures were captured by a novel foot-based audit tool that recorded fine-detail neighbourhood features relevant to PA in older adults, and routine data. RESULTS: 795 men and 638 women aged 69-92 years from two national cohorts, covering 20 British towns, were included in the analysis. Median time in moderate to vigorous PA (MVPA) was 27.9 (lower quartile: 13.8, upper quartile: 50.4) minutes per day. There was little evidence of associations between any of the physical environmental domains (eg, road and path quality defined by latent class analysis; number of bus stops; area aesthetics; density of shops and services; amount of green space) and MVPA. However, analysis of area-level income deprivation suggests that the social environment may be associated with PA in this age group. CONCLUSIONS: Although small effect sizes cannot be discounted, this study suggests that older individuals are less affected by their local physical environment and more by social environmental factors, reflecting both the functional heterogeneity of this age group and the varying nature of their activity spaces
    corecore