Geopolymer ultrahigh performance concrete: Material and performance

During the last two decades, considerable progress has been made in the development of ultra-high-performance concrete (UHPC) with ordinary Portland cement (OPC). UHPC represents a major development step over high performance concrete (HPC), through the achievement of very high compressive strength (over 20,000 psi or 140 MPa) and superior durability due to very low permeability compared to high-performance concrete; in some cases, fibers are included to achieve improved ductility. Despite these performance advantages, deployment of Portland cement-based UHPC has been slow, in part due to the relatively high compared to that of conventional concrete components. In addition, the higher content of Portland cement in UHPC, high temperature steam curing, and use of relatively large amounts of superplasticizers increase the cost and CO2 footprint. Geopolymer-based UHPCs have the potential for significant advantages over comparable OPC-based materials. We have developed a range of low-cost, low-CO2 footprint, geopolymer UHPC (GUHPC) formulations. The main characteristics of these GUHPCs include: 1) Increased homogeneity by excluding aggregates \u3e9.5mm, 2) Increased packing density through use of micro- and nano-particles, 3) Very low water-to-binder ratio through chemically tailored activator compositions and use of intensive mixing; 4) Composite binders yielding hybrid calcium aluminosilicate hydrate (C-A-S-H) and alkali aluminosilicate hydrate (A-A-S-H) gels to improve product properties; and 5) Regulation of set times using a very effective inorganic retarder. Please click Additional Files below to see the full abstract

EMMEL: a framework for historical manuscript analysis and presentation

In this paper, a generic framework for historical manuscript image and data processing, visualisation and analysis is introduced with a focus on the modelling of manuscript metadata underpinning the interaction. The goal of such a framework is to capture the requirements from three types of activities involving historical manuscripts: presentation, management and analysis. In addition to an overall text-based description of an historical manuscript, a central requirement of such a framework is to associate rich media information (e.g. video, flash component, etc.) to the manuscript or a specific region of the manuscript. A second requirement is to enable interchange of the manuscript data as well as the attached information between users. As a result of an extensive analysis of requirements collected across a wide range of target user groups, an XML-based metadata language derived from a relational database model is proposed to form an historical document data model, and a prototype system is developed to demonstrate some of the advanced functionalities enabled by this data model. Thus, the proposed framework provides an important tool in promoting access to historical documents on a wide and diverse basis, embracing the fundamental principles of universal access to a shared cultural heritage