Approaches and strategy development towards more sustainable ultra-high-performance concrete

The main research objective of this thesis is to investigate how the use of UHPC can contribute to improving the sustainability of the concrete industry by investigating alternative approaches and develop a comprehensive strategy. Some cost aspects have been discussed to indicate whether the strategy is commercially viable. The research involved six studies: Paper I describes a background study to identify directions for a more sustainable concrete industry. Papers II–V report on how approaches to improve sustainability influence the mechanical properties of UHPC. These studies include both literature reviews and experimental activities. Paper VI concludes the research by developing a comprehensive strategy to use UHPC for a more sustainable concrete industry. Because most of the CO2 emissions (about 95%) from UHPC materials originate from the production of cement and micro steel fibres, the more efficient use of these materials is a vital step. Several different approaches have been investigated and determined to be efficient. Some approaches identified from attempts aimed at achieving a more efficient application of cement in normal concrete may be transferred to UHPC. These include partial substitution with both binding and inert materials, combined with better particle packing. The use of steel fibres was observed to have the potential to be more effective by enhancing the pull-out properties using longer or deformed fibres and hybrid fibre combinations. The use of industrial by-products or construction and demolition waste as partial replacements for cement or as aggregates was also observed as being feasible. The local development and production of UHPC builds competence, which is vital for the widespread use of UHPC. The research concludes with the formulation of a comprehensive strategy on how the development and use of UHPC can contribute to improving the sustainability of the concrete industry.publishedVersio

A Low-Cost Apparatus for Laboratory Exercises and Classroom Demonstrations of Geometric Optics

Current trends in research towards the teaching of geometric suggest a constructivist approach. Student experimentation dealing directly with student misconceptions through repetition of examples in many contexts to confront conflicting reasoning allow students to construct definitions with their experiences and observations. Developing the scientific method of observation, prediction/experimental design, conducting experiments and repeating is reinforced with these techniques. Cataloguing student misconceptions and redesigning course material and laboratory experiments in their context has only recently begun. Use of technology has also been shown to increase student interest in course material and 3D printers have recently become common tools in schools. Additionally, experiments that lend themselves towards computer modeling are sought after as an interface to reconcile conflicting reasoning in student misconceptions. An apparatus and set of experiments is described that deal with student misconceptions in iterative experiments. Overall cost of the system is decreased by 3D printing expensive optical components. The system highlights complex interactions of propagating light waves and seeks to explain the effects of media on image formation

UAH/NASA Workshop on The Uses of a Tethered Satellite System

Potential applications of the system are categorized into four areas: geological applications, atmospheric applications, electrodynamics and plasma studies, and technology applications. The multiple-use tethered system with feedback control, will be capable of supporting a payload or satellite suspended from the Shuttle cargo bay, at distances up to 100 kilometers from the Shuttle. Experiments proposed include: geomagnetic mapping, lower atmospheric measurements, ionospheric interactions with large space structures, solar wind transport, and magnetohydrodynamic measurements

Volume II: Mining Innovation

Contemporary exploitation of natural raw materials by borehole, opencast, underground, seabed, and anthropogenic deposits is closely related to, among others, geomechanics, automation, computer science, and numerical methods. More and more often, individual fields of science coexist and complement each other, contributing to lowering exploitation costs, increasing production, and reduction of the time needed to prepare and exploit the deposit. The continuous development of national economies is related to the increasing demand for energy, metal, rock, and chemical resources. Very often, exploitation is carried out in complex geological and mining conditions, which are accompanied by natural hazards such as rock bursts, methane, coal dust explosion, spontaneous combustion, water, gas, and temperature. In order to conduct a safe and economically justified operation, modern construction materials are being used more and more often in mining to support excavations, both under static and dynamic loads. The individual production stages are supported by specialized computer programs for cutting the deposit as well as for modeling the behavior of the rock mass after excavation in it. Currently, the automation and monitoring of the mining works play a very important role, which will significantly contribute to the improvement of safety conditions. In this Special Issue of Energies, we focus on innovative laboratory, numerical, and industrial research that has a positive impact on the development of safety and exploitation in mining

Proceedings of the 9th fib International PhD Symposium in Civil Engineering : Karlsruhe Institute of Technology (KIT), 22 - 25 July 2012, Karlsruhe, Germany

The fib International PhD Symposium in Civil Engineering is an established event in the academic calendar of doctoral students. It is held under the patronage of the International Federation for Structural Concrete (fib), one of the main international associations that disseminates knowledge about concrete and concrete structures. The 9th fib International PhD Symposium was held at the Karlsruhe Institute of Technology (KIT), Germany, from July 22 to 25, 2012