Design, construction and evaluation of a 12.2 GHz, 4.0 kW-CW high efficiency klystron amplifier

An analytical and experimental program is described, for studying design techniques for optimizing the conversion efficiency of klystron amplifiers, and to utilize these techniques in the development and fabrication of an X-band 4 kW cw klystron, for use in satellite-borne television broadcast transmitters. The design is based on a technique for increasing the RF beam current by using the second harmonic space charge forces in the bunched beam. Experimental analysis was also made of a method to enhance circuit efficiency in the klystron cavities. The design incorporates a collector which is demountable from the tube to facilitate multistage depressed collector experiments employing an axisymmetric, electrostatic collector for linear beam microwave tubes

Mechanisms and interaction phenomena influencing releases in low- and medium-level waste disposal systems. Final report 1986-1990

The report covers work done 1986-1990 at Risø National Laboratory as part of the third EC Research Programme on Radioactive Waste Management.Waste product characterization:- If aching and volume stability of cemented ion-exchange resins. Wet/dry cycling was found to be an important degradation mechanism.- Hygroscopic properties of cemented and bituminized radioactive waste. Water uptake from the air can be an important release mechanism when waste containing soluble salts are disposed of by shallow land burial.- Water uptake and swelling of bttuminized waste including studies of water migration in bitumen membranes and measurements of swelling pressures.- Ageing of bituminized products was demonstrated to result in increasing stiffness of the materials.- Nickel ferrocyanide in precipitation sludge was found to be unstable in contact with concrete. Barrier material properties:- The influence of the pore structure in concrete on the hydraulic or diffusive transport of water and ions through concrete barriers was investigated. The main parameter is the water/cement ratio. A theoretical interpretation is given.- Healing of cracks in concrete barriers by precipitation of calcium carbonate was demonstrated experimentally and described by a simplified model.- Transport of components between two thin plates of cement paste with different composition stored together is water was found to take place at a low rate.- The structure of degraded cement paste was studied using SANS (small angle neutron scattering).Interaction phenomena:- Integral experiments with migration of radioisotopes from cemented waste through barriers made from kaolin, chalk or concrete were made under different external conditions. The results can be used for model validation and some preliminary work was done

The European arrest warrant and in absentia judgments:The cause of much trouble

The ground for optional refusal of Article 4a FD 2002/584/JHA was intended to strengthen the rights of defendants and make the execution of European Arrest Warrants after in absentia convictions easier. In practice, however, problems at the level of the EU legislator, at the level of national legislators and at the level of judicial authorities seem to stand in the way of achieving those goals. A common thread of the problems with applying Article 4a is a lack of awareness of the case-law of the European Court of Justice. Based on case studies from six EU Member States, this article makes an in-depth analysis of these problems and suggests concrete measures on how to overcome them

Nanoparticle- and microparticle-based luminescence imaging of chemical species and temperature in aquatic systems: a review

© 2019, Springer-Verlag GmbH Austria, part of Springer Nature. Most aquatic systems rely on a multitude of biogeochemical processes that are coupled with each other in a complex and dynamic manner. To understand such processes, minimally invasive analytical tools are required that allow continuous, real-time measurements of individual reactions in these complex systems. Optical chemical sensors can be used in the form of fiber-optic sensors, planar sensors, or as micro- and nanoparticles (MPs and NPs). All have their specific merits, but only the latter allow for visualization and quantification of chemical gradients over 3D structures. This review (with 147 references) summarizes recent developments mainly in the field of optical NP sensors relevant for chemical imaging in aquatic science. The review encompasses methods for signal read-out and imaging, preparation of NPs and MPs, and an overview of relevant MP/NP-based sensors. Additionally, examples of MP/NP-based sensors in aquatic systems such as corals, plant tissue, biofilms, sediments and water-sediment interfaces, marine snow and in 3D bioprinting are given. We also address current challenges and future perspectives of NP-based sensing in aquatic systems in a concluding section. [Figure not available: see fulltext.]

Bayesian mixed-effects inference on classification performance in hierarchical data sets

Classification algorithms are frequently used on data with a natural hierarchical structure. For instance, classifiers are often trained and tested on trial-wise measurements, separately for each subject within a group. One important question is how classification outcomes observed in individual subjects can be generalized to the population from which the group was sampled. To address this question, this paper introduces novel statistical models that are guided by three desiderata. First, all models explicitly respect the hierarchical nature of the data, that is, they are mixed-effects models that simultaneously account for within-subjects (fixed-effects) and across-subjects (random-effects) variance components. Second, maximum-likelihood estimation is replaced by full Bayesian inference in order to enable natural regularization of the estimation problem and to afford conclusions in terms of posterior probability statements. Third, inference on classification accuracy is complemented by inference on the balanced accuracy, which avoids inflated accuracy estimates for imbalanced data sets. We introduce hierarchical models that satisfy these criteria and demonstrate their advantages over conventional methods usingMCMC implementations for model inversion and model selection on both synthetic and empirical data. We envisage that our approach will improve the sensitivity and validity of statistical inference in future hierarchical classification studies. © 2012

Den rådne banan på kort : Visuel literacy - fra billeder til viden

Mange taler om ”Udkantsdanmark”, men ingen gør tilsyneladende nogetvirkningsfuldt ved det, selv om regeringen kommer med politiske udspil, ændrer lovgivningen og opfinder nye støttemuligheder i lange baner. Det er der givetvis forskellige årsager til. En kunne være, at det slet ikke er ønsket, at der gøres noget virkningsfuldt ved Udkantsdanmark. En andenkunne være, at debatgrundlaget og den præsenterede information er for ringe. Artiklen viser eksempler på kort fra den eksisterende, ikke altid konstruktive debat om Udkantsdanmark. Som modstykke hertil præsenteres i artiklen utraditionelle kort, der er designet til netop somvisual literacy at bidrage til, at der overhovedet bliver en reel debat om Udkantsdanmark & Kernedanmark.Artiklen fremlægger ikke et politisk synspunkt. Artiklen præsenterer, hvor forbløffende effektivt politiske synspunkter kan fremlægges ved at tænke og agere i visual literacy. Artiklens budskab er at fremme den konstruktive debat generelt, hvor Den Rådne Banan og kortene blot tjener som eksempel