Kaspar Lasn

Bio: Kaspar Lasn is an academic researcher from Norwegian University of Science and Technology. The author has contributed to research in topics: Pressure vessel & Lamb waves. The author has an hindex of 8, co-authored 15 publications receiving 151 citations. Previous affiliations of Kaspar Lasn include Tallinn University of Technology.

Evaluation of stiffness and damage of laminar composites

Abstract: .................................................................................................................................... iii Sisukokkuvõte ........................................................................................................................... iv Sammendrag ............................................................................................................................... v List of publications .................................................................................................................... vi Peer-reviewed publications in international journals ............................................................ vi Presentations at international conferences ............................................................................. vi Table of contents ........................................................................................................................ 1 Abbreviations and notations ....................................................................................................... 6

Experimental determination of elastic constants of an orthotropic composite plate by using lamb waves

Abstract: An inversion procedure is described to determine the elastic constants of an orthotropic plate by using experimental data on Lamb wave propagation and a curve fitting algorithm based on the Nelder–Mead simplex method. A sample made from glass-epoxy was tested and eight out of nine engineering constants were recovered from Lamb wave propagation measurements in the principal material directions. To improve convergence, the phase velocity sensitivities to different elastic constants are considered. The inversion results agree rather well with experimental data and static tension measurements for the longitudinal elastic modulus.

Hydrogen: A sustainable fuel for future of the transport sector

Abstract: Mobility (transport of people and goods) is a socio-economic reality and need for which is bound to grow in the coming years. Modes of transport should be safe, economic and reasonably environmental friendly. Hydrogen could be ideal as a synthetic energy carrier for transport sector as its gravimetric energy density is very high, abundantly available in combined form on the earth and its oxidation product (water) does not contribute to greenhouse gas emissions. However, its sustainable production from renewable resources economically, on-board storage to provide desirable driving range, usage in durable energy conversion devices and development of infrastructure for its delivery remain significant challenges. In this article, recent developments in the field of production, storage, transport and delivery of hydrogen along with environmental and safety aspects of its use as an energy carrier are presented. Almost any energy source can be used to produce hydrogen. Presently, non-renewable sources dominate hydrogen production processes but the need of the hour is to develop and promote the share of renewable sources for hydrogen production to make it completely sustainable. Hydrogen may be used as fuel for almost any application, where fossil fuels are used presently and would offer immediate benefits over the conventional fuels, if produced from renewable sources. For achieving a successful "hydrogen economy" in the near future, the technical and economic challenges associated with hydrogen must be addressed quickly. Finding feasible solutions to different challenges may take some time but technological breakthrough by way of on-going efforts do promise hydrogen as the ultimate solution for meeting our future energy needs for the transport sector.

An overview of development and challenges in hydrogen powered vehicles

Abstract: Hydrogen has the potential to be the sustainable fuel of the future, decrease the global dependence on fossil fuel resources, and lower the pollutant emissions from the transportation industry. In ...

Experimental study on hydrogen explosions in a full-scale hydrogen filling station model

Abstract: In order for fuel cell vehicles to develop a widespread role in society, it is essential that hydrogen refueling stations become established. For this to happen, there is a need to demonstrate the safety of the refueling stations. The work described in this paper was carried out to provide experimental information on hydrogen outflow, dispersion and explosion behaviour. In the first phase, homogeneous hydrogen-air-mixtures of a known concentration were introduced into an explosion chamber and the resulting flame speed and overpressures were measured. Hydrogen concentration was the dominant factor influencing the flame speed and overpressure. Secondly, high-pressure hydrogen releases were initiated in a storage room to study the accumulation of hydrogen. For a steady release with a constant driving pressure, the hydrogen concentration varied as the inlet airflow changed, depending on the ventilation area of the room, the external wind conditions and also the buoyancy induced flows generated by the accumulating hydrogen. Having obtained this basic data, the realistic dispersion and explosion experiments were executed at full-scale in the hydrogen station model. High-pressure hydrogen was released from 0.8-8.0mm nozzle at the dispenser position and inside the storage room in the full-scale model of the refueling station. Also the hydrogen releases were ignited to study the overpressures that can be generated by such releases. The results showed that overpressures that were generated following releases at the dispenser location had a clear correlation with the time of ignition, distance from ignition point. INTRODUCTION In order for the ‘hydrogen economy’ to become a reality, not only is their a requirement to develop the fuel cell technology and associated equipment and infrastructure in an economic manner, but also it is necessary to demonstrate that all aspects of the supply and use of hydrogen can be performed safely. Osaka Gas Co., Ltd. has been operating a hydrogen refuelling station [1] safely as a demonstration plant, in parallel with developing a compact hydrogen reformer [2], (see Figure 1). However, in 2003, Osaka Gas joined the Japanese National Project on Hydrogen, with the aim of carrying out further work to investigate the safety aspects of hydrogen refuelling stations. One of the particular aims of this work was to help establish a suitable ‘safety zone’ around such a station. Figure 1: Osaka Gas’s hydrogen station (left) and hydrogen production unit, HYSERVE (right)