41,900 research outputs found

    Evidence of exchange networks: the combs and other worked skeletal material

    Get PDF
    Significant contribution to the study of skeletal material in the Norse period using large internationally significant assemblage from Norse site in Orkney

    Designing identity of a new material: a new product design approach

    Get PDF
    The present research is a design practice-based research based on the industrial development of a new concrete. The research focuses on the development of the specific identity of a new material. The research is aimed at demonstrating that product design can be used as a new strategy to create the material identity and thus to differentiate from existing materials. In order to design material specific identity in new products, we need to understand the perception process of shaped materials. Therefore we conducted exploratory study of materials recognition in products. We identified two types of products: the “messenger” products are specific shapes characteristic from the material; the “wrong messenger” products are imitations of other well known materials. The results of questionnaire about material recognition show that it’s more or less easy to identify material according to each product (whether it’s familiar or new shapes; whether it’s imitation or specific shapes and whether it’s well known or new material). We conclude on two types of shapes: on the one hand some familiar and typical shapes make easier and more certain the material recognition; on the other hand some new shapes make people more uncertain of what it is made of but more amazed. Designing amazing new shapes can be used as a new differentiation strategy to create the specific sensory identity of each new material. It means that the product can be a really useful support to fully communicate about a new material, beyond the traditional material samples. Keywords: New Material; Sensory Identity; Product Design</p

    Mechanical Properties of APbX3 (A=Cs or CH3NH3; X=I or Br) Perovskite Single Crystals

    Full text link
    The remarkable optoelectronic, and especially photovoltaic performance of hybrid-organic-inorganic perovskite (HOIP) materials drives efforts to connect materials properties to this performance. From nano-indentation experiments on solution-grown single crystals we obtain elastic modulus and nano-hardness values of APbX3 (A = Cs, CH3NH3 and X = I, Br). The Youngs moduli are about 14, 19.5 and 16 GPa, for CH3NH3PbI3, CH3NH3PbBr3 and CsPbBr3, respectively, lending credence to theoretically calculated values. We discuss possible relevance of our results to suggested self-healing, ion diffusion and ease of manufacturing. Using our results, together with literature data on elastic moduli, we classified HOIPs amongst relevant materials groups, based on their elasto-mechanical properties.Comment: 20 pages (including 4 pages of Supporting Information after the references), 3 figures (+3 in the Supporting Information), 2 tables (+1 in the Supporting Information

    Determination of a set of constitutive equations for an al-li alloy at SPF conditions

    Get PDF
    © 2015 The Authors.Uniaxial tensile tests of aluminium-lithium alloy AA1420wereconducted at superplastic forming conditions. The mechanical properties of this Al-Li alloy were then modelled by a set of physicallybased constitutive equations. The constitutive equations describe the isotropic work hardening,recovery and damage by dislocation density changes and grain size evolution. Based on a recent upgraded optimisation technique, the material constants for these constitutive equations were determined

    Selection of Gate Dielectrics for ZnO Based Thin-Film Transistors

    Full text link
    The bulk of semiconductor technology has been based on silicon till today. But silicon has its own limitations. It is not transparent to visible light and hence it cannot be used in certain applications. ZnO is a material which is transparent to visible light. In this paper, we compare the electrical performance of ZnO Thin film Transistors using different gate insulators. Certain performance indices and material indices were considered as the selection criteria for electrical performance. A methodology known as Ashby\u27s approach was adopted to find out the best gate insulators and based on this methodology various charts were plotted to compare different properties of competing materials. This work concludes that Y2O3 is the best insulator followed by ZrO2 and HfO2

    Transverse fracture properties of green wood and the anatomy of six temperate tree species

    Get PDF
    © Institute of Chartered Foresters, 2016. All rights reserved. The aim of this study was to investigate the effect of wood anatomy and density on the mechanics of fracture when wood is split in the radial-longitudinal (RL) and tangential-longitudinal (TL) fracture systems. The specific fracture energies (Gf, J m-2) of the trunk wood of six tree species were studied in the green state using double-edge notched tensile tests. The fracture surfaces were examined in both systems using Environmental Scanning Electron Microscopy (ESEM). Wood density and ray characteristics were also measured. The results showed that Gf in RL was greater than TL for five of the six species. In particular, the greatest degree of anisotropy was observed in Quercus robur L., and the lowest in Larix decidua Mill. ESEM micrographs of fractured specimens suggested reasons for the anisotropy and differences across tree species. In the RL system, fractures broke across rays, the walls of which unwound like tracheids in longitudinal-tangential (LT) and longitudinal-radial (LR) failure, producing a rough fracture surface which would absorb energy, whereas in the TL system, fractures often ran alongside rays

    A knowledge-based decision support system for roofing materials selection and cost estimating: a conceptual framework and data modelling

    Get PDF
    A plethora of materials is available to the modern day house designer but selecting the appropriate material is a complex task. It requires synthesising a multitude of performance criteria such as initial cost, maintenance cost, thermal performance and sustainability among others. This research aims to develop a Knowledge-based Decision support System for Material Selection (KDSMS) that facilitates the selection of optimal material for different sub elements of a roof design. The proposed system also has a facility for estimating roof cost based on the identified criteria. This paper presents the data modelling conceptual framework for the proposed system. The roof sub elements are modelled on the Building Cost Information Service (BCIS) Standard Form of Cost Analysis. This model consists of a knowledge base and a database to store different types of roofing materials with their corresponding performance characteristics and rankings. The system s knowledge is elicited from an extensive review of literature and the use of a domain expert forum. The proposed system employs the multi criteria decision method of TOPSIS (Technique of ranking Preferences by Similarity to the Ideal Solution), to resolve the materials selection and optimisation problem. The KDSMS is currently being developed for the housing sector of Northern Ireland

    Assessing the impact of participatory research in rice breeding on poor rice farming households with emphasis on women farmers: a case study in eastern Uttar Pradesh, India

    Get PDF
    For the past years since the Consultative Group of International Agricultural Research (CGIAR) Systemwide Initiative on Participatory Research and Gender Analysis (PRGA) was initiated, guides for impact assessment of PRGA have been developed (Lilja and Ashby 1999; Johnson et.al., 2000; Lilja and Johnson 2001). However, according to Farnworth and Jiggins (2003) while there is rapidly growing literature on the impacts of PPB on farmers, this is not further differentiated by sex. Despite the immense literature on the impacts of production, post production technologies on women farmers, systematic studies on the impacts of PPB on women in any category, either in terms of the effects of being a participant in a participatory plant breeding process (PPB) process, or in terms of the impact of the new materials generated is few. There is practically no literature that examines the effects of PPB – either as process or in terms of the impacts of the emergent materials – on gender relations at the household, community or any other relevant social or geographic scale along the food chain. Even with women’s active involvement in rice production, post harvest and seed management, scientists who are mostly male often talk with the male farmers only. Ignoring women’s knowledge and preference for rice varieties may be an obstacle to adoption of improved varieties, particularly in areas with gender-specific tasks, and in farm activities where women have considerable influence. Feldstein (1996) cited three different ways in which gender analysis can be considered in participatory research. These are: the efficiency argument, equity oriented, and empowerment. This study attempts to fill in these research gaps. The objectives of this paper are to: a) discuss the process used in integrating participatory research and gender analysis in breeding for drought prone and submergence prone environment; b) assess how gender analysis contributed to the design and implementation of the research and development outcomes; c) assess the impacts of PVS on poor women farmers, particularly on women’s empowerment; and d) recommend strategies to further enhance women’s roles in ensuring household food (rice) food security and improving their social status within the household and the community
    corecore