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Transient waves in nonstationary media : with applications to lightning and nonlinear media

Popular Abstract in Swedish Avhandlingen behandlar problem inom den tillämpade matematiken med speciell inriktning mot elektromagnetisk vågutbredning. Exempel på studerade elektromagnetiska vågor är radiovågor, mikrovågor och ljus. Det speciella som skiljer den här studien från andra liknande studier, är att det medium som vågen passerar genom är ickestationärt, vilket innebär att det ändras underPropagation of transient waves in nonstationary, inhomogeneous, dispersive, stratified media is considered. Waves originating from sources exterior to the scatterer as well as from internal sources are treated. Algorithms are developed and illustrated by computations of wave phenomena in stationary, nonstationary and weakly nonlinear media. In the theoretical part, the underlying hyperbolic equati

Power generation from low heat sources

In this chapter a thorough review of the latest research findings on power generation from non-conventional low heat sources is presented. Main discoveries and results of research works ranging from source exploitation technologies to final power production are reported and discussed to offer an overview of their potential. Firstly the concept of low-grade source is presented and the main energy s

In-cylinder Surface Thermometry using Laser Induced Phosphorescence

Surface temperature in internal combustion engines is of high interest when studying heat losses. Two approaches for retrieving the surface temperatures are thermocouples and Laser Induced Phosphorescence, LIP. This study aims to analyze LIP as a technique for measuring surface temperature in internal combustion engines. The motivation for this study is the need for accurate surface temperatures w

A genetic component to resistance to fungal infection in frog embryos

The embryo has traditionally been considered to completely rely upon parental strategies to prevent threats to survival posed by predators and pathogens, such as fungi. However, recent evidence suggests that embryos may have hitherto neglected abilities to counter pathogens. Using artificial fertilization, we show that among-family variation in the number of Saprolegnia-infected eggs and embryos i

All-spectrum oblique transmission through a periodic screen

We show that the all-spectrum transmission blockage through a low-pass screen is bounded by the static polarizability per unit area of the screen, irrespective of how complicated the materials involved are. The angular dependence at oblique incidence is investigated, and the results are verified by measurements on an array of split ring resonators.

Spatio-Temporal Estimation for Mixture Models and Gaussian Markov Random Fields - Applications to Video Analysis and Environmental Modelling

In this thesis computationally intensive methods are used to estimate models and to make inference for large, spatio-temporal data sets. The thesis is divided into two parts: the first two papers are concerned with video analysis, while the last three papers model and investigate environmental data from the Sahel area in northern Africa. In the first part of the thesis, mixture models are used to

Cabotagestudien - A study on the movement of international vehicles in Denmark

An open European market for goods and services, including transport services, stimulates trade, global competitiveness and economic growth. At the same time, concerns about domestic job security and the environment have sparked debate. This report should be considered a first modest contribution to a mainly unexplored area in the past. Cabotagestudien consists of a walkthrough of previous research

Low power, highly stable and wideband LNA for GNSS applications in SiGe technology

A low power wideband low noise amplifier (LNA) was designed and implemented in SiGe HBT technology. The measured noise figure is less than or equal to 1 dB in almost the entire L-band. The gain in the L-band is above 13 dB with a gain variation of 4 dB. Hence, it’s useful for present as well as future GNSS applications. The current consumption is 5 mA from a single supply of +5V. The stability of

Secondary Metabolites from Bolivian Plants- Isolation and Characterization

Popular Abstract in English Plants produce an array of organic chemicals with an enormous diversity of structural types. Many of these phytochemicals are biologically active compounds necessary for the well-being, survival, and evolution of the plants, but also have been used by humans, who have used them in traditional medicine and for pharmaceutical industry. During the course of this research, Nature has been recognized as a rich source of potentially useful chemicals. Throughout the years, phytochemical studies have led to the discovery of an enormous number of natural products, their chemical diversity is unique and many of them possess various biological activities. As a contribution, this thesis presents the results obtained from the phytochemical study of four Bolivian plants. Sene

Amphiphilic Graft Copolymer Electrolytes for Lithium-Ion Polymer Batteries. - Preparation and Characterisation

In the present work amphiphilic graft copolymers were prepared by free radical copolymerization of macromonomers in solution. The graft copolymers consisted of methacrylate backbones bearing ethylene oxide (EO)n side chains of varying length as ionophilic groups, and fluorocarbon (CF2)6 side chains or hydrocarbon groups as ionophobic groups. Homogenous polymer gel electrolytes were prepared by add