A dual band antenna for two ISM bands at 2.4 GHz and 5 GHz has been evaluated. The antenna structure derives its advantage by deploying several radiators as fingers spreading from a single feeding point. Each radiator functions as both a half-wave and a quarter-wave radiator. Arranging them in parallel matches the half-wave resonance to 50 W. By carefully selecting the angle to ground plane and us

Fuel cells (FCs) are promising for future energy systems, since they are energy efficient and fuel can be produced locally. When hydrogen is used as fuel, there are no emissions of greenhouse gases. In this study a two dimensional CFD (COMSOL Multiphysics) is employed to study the effect from porous material surface area ratio on reforming reaction rates and gas species distributions for an anode-

Popular Abstract in Swedish Växter är en av den största grupperna av organismer på jorden. Den här gruppen av organismer kan syntesisera kolhydrater med solenergi. I växter används en stor del av kolhydraterna till att bilda förnyelsebara polysackarider som sedan används för att bygga upp vedstrukturer. Den mest kända växtpolysackariden är cellulosa som består av långa kedjor av glukos. Den näst mHemicellulose is the second most abundant group of renewable polysaccharides. Mannans can be found as the major hemicellulose in softwood and as storage polysaccharides in a range of plants. In this work, structural and functional characterisations of family 5 and 26 endo-1,4-b-mannanases (b-mannanases) have been performed. These families belong to the large and diverse glycoside hydrolase clan A,

Climate change and disasters are among today’s most pressing issues. The damage caused by the world-wide increase in disasters is staggering, with the urban poor being most at risk. Disasters make their al-ready precarious living conditions worse, creating a vicious circle of poverty. More and more attention has thus been given to the need to address changing climatic conditions and disaster risk

Stress corrosion, SC, in some cases gives rise to stress corrosion cracking, SCC, which differs from purely stress intensity driven cracks in many aspects. They initiate and grow under the influence of an aggressive environment in a stressed substrate. They grow at low load and may branch. The phenomenon of SCC is very complex, both the initiation phase and crack extension itself of SCC is seeming

Popular Abstract in Swedish Trots att "block- och ymp- sampolymerer" låter obekant i de flestas öron, kommer vi i kontakt med dem i det vardagliga livet. De kan användas till en rad olika produkter t.ex. leksaker, färg, papper, tvättmedel, läkemedel, kosmetika och i bilar. Denna avhandling handlar om framställning och karatärisering av ympsampolymerer, samt studier av deras egenskaper i vattenlösThe research underlaying this thesis involves synthesis and characterization of well-defined anionic graft copolymers carrying poly(ethylene oxide) (PEO) side-chains. Two different grafting techniques were used. Backbone polymers were prepared through radical terpolymerization of maleic anhydride, styrene and an additional comonomer. Poly(ethylene oxide) monomethyl ether (MPEO) were grafted onto

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We introduce and analyze new constructions of LDPC convolutional codes and their tail-biting versions which are obtained from braided convolutional codes. The basic ideas behind the encoding and decoding architectures for these codes are presented. Additionally, asymptotic results concerning the iterative thresholds are shown for different ensembles. Finally, we evaluate the bit error rate perform

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