Spannungsschwankungen und Licht-Flicker nach dem Ausstieg aus der Glühlampentechnologie

In vielen Ländern legen die Normen IEC 61000-3-3 [1] und IEC 61000-3-11 [2] verbindlich fest, welche Spannungsschwankungen von Geräten am öffentlichen Stromversorgungsnetz erzeugt werden dürfen. Die Festlegungen dienen unter anderem der Begrenzung von Licht-Flicker und beruhen auf der alten Annahme, dass in einem Haushalt vorwiegend Glühlampen zur Beleuchtung verwendet werden. Da die Glühlampentechnologie jetzt vom Markt verschwindet, ergibt sich eine neue Situation. Dieser Beitrag beschreibt, wie unter den neuen Bedingungen die EMV bezüglich Licht-Flicker aufrechterhalten werden soll

Clinical applications of the Medipix detector

In this thesis a recently developed energy resolving x-ray detector (Medipix) is used to investigate potential medical applications of spectral x-ray imaging. Computed Tomography (CT) is one of the most important medical imaging modalities. Recent developments in CT techniques include dual-energy CT, where images are taken with two different x-ray spectra by either using two x-ray tubes operated at different voltages, or modulating the operating voltage of a single tube. These techniques provide spectral information in the CT dataset but are limited to what can be achieved by manipulating the x-ray source, since the detectors used in current CT systems are unable to provide spectral information about the detected x-rays. A preliminary investigation of the use of the Medipix detectors for two different medical applications is presented. The first, applications is imaging of blood vessels for diagnosis of vascular diseases, and the second, characterising and measuring the energy dependence of x-ray attenuation in fat and liver tissue using the Medipix2 detector. This second investigation is part of work towards (eventually) quantifying the fat content of liver tissue in vivo, which is important for the early diagnosis of fatty liver disease. While an early attempt to identify iron fluorescence x-rays in a Monte-Carlo simulation of blood vessel x-ray image was not successful, the potential for improving image contrast using the changes in x-ray attenuation at the iodine k-edge iodine have been investigated in a series of further simulations and appears to be feasible. The potential use of spectral imaging to differentiate and quantify tissues without the need for added contrast material has been investigated by using a Medipix2 detector to measure the energy dependence of x-ray absorption in fat and liver tissue. The results of this experimental work show significant differences in x-ray attenuation between these two tissues that suggest this form of spectral imaging may be useful in practice

Soil Water Movement in Vapor and Liquid Phases

One of the well-known characteristics of arid region soils is that the temperature undergoes wide fluctuations throughout the day and throughout the season. These temperature variations induce thermal gradients and temperature differences between locations in the surface soil. Although the existence of these effects is well known, their effect on the processes that occur in the soil is not so well known. One of the problems that has been of considerable interest in recent years is the influence of temperature differences upon the movement of water in the soil. Early investigators of this problem discovered that there was a net water flux from warm to cold in soil materials subjected to a thermal difference, but they became involved in a controversy as to whether the movement was in the vapour or liquid phase. Some studies supported the concept of flow in the vapour phase, and others supported the concept of flow in the liquid phase. A net flux of vapour from warm to cold and liquid from cold to warm was demonstrated in an enclosed and sealed system of porous material, water, and air by Krischer and Rohnalter (1940). This was later confirmed for soil material, using a different technique, by Gurr, Marshall and Hutton (1952), but they obtained a vapour diffusion coefficient that was very much greater than expected on the basis of simple laws of diffusion. Similar studies in sealed systems, using still different techniques, were reported by Taylor and Cavazza (1954), who found that the apparent vapour diffusion coefficient was ten times larger than expected on the basis of simple diffusion laws. Subsequently,. there have been repeated observations of this effect, and several attempts to explain the phenomena based on various analyses of simultaneous movement of water and heat (Philip and Dc Vries. 1957; De Vries, 1958; Derjaguin and Melnikova, 1958)

The significance of beam steering on laser-induced incandescence measurements in laminar counterflow flames

Published online: 17 October 2018Beam steering is often encountered in laser diagnostic measurements, especially in flame environments, due to changes in refractive index caused by thermal and species gradients. It can negatively affect the accuracy of the results. In this work, the effects of beam steering on laser-induced incandescence (LII) measurements of pre-vaporized-liquid counterflow flames are assessed. The focus on counterflow flames is to facilitate future detailed experimental campaigns on one-dimensional nonpremixed sooty flames. It is found that the temperature and species gradients in the counterflow configuration have a much more significant impact on the beam profile than in laminar flat flames, especially for heavier fuels. As a result of the changes in the beam profile, for the same applied laser energy, the local fluence shifts markedly with fuel type, therefore, having a direct impact on the LII measurements. A procedure is developed for ensuring accurate measurements and it is shown that, for a specific fuel, it is possible to tailor the laser energy, such that the collected LII signal in the counterflow flames is nearly independent of beam-steering effects.S. Kruse, P. R. Medwell, J. Beeckmann, H. Pitsc

Genetic diversity of eleven European pig breeds

A set of eleven pig breeds originating from six European countries, and including a small sample of wild pigs, was chosen for this study of genetic diversity. Diversity was evaluated on the basis of 18 microsatellite markers typed over a total of 483 DNA samples collected. Average breed heterozygosity varied from 0.35 to 0.60. Genotypic frequencies generally agreed with Hardy-Weinberg expectations, apart from the German Landrace and Schwäbisch-Hällisches breeds, which showed significantly reduced heterozygosity. Breed differentiation was significant as shown by the high among-breed fixation index (overall FST = 0.27), and confirmed by the clustering based on the genetic distances between individuals, which grouped essentially all individuals in 11 clusters corresponding to the 11 breeds. The genetic distances between breeds were first used to construct phylogenetic trees. The trees indicated that a genetic drift model might explain the divergence of the two German breeds, but no reliable phylogeny could be inferred among the remaining breeds. The same distances were also used to measure the global diversity of the set of breeds considered, and to evaluate the marginal loss of diversity attached to each breed. In that respect, the French Basque breed appeared to be the most "unique" in the set considered. This study, which remains to be extended to a larger set of European breeds, indicates that using genetic distances between breeds of farm animals in a classical taxonomic approach may not give clear resolution, but points to their usefulness in a prospective evaluation of diversity

Stratospheric ozone profiles monitoring with DIAL technique in Río Gallegos

El adelgazamiento de la capa de ozono sobre el polo sur de nuestro planeta es un fenómeno estacional que desde la década de los ‘80 se desarrolla cada año durante la primavera. El mismo tiene su máxima expresión sobre la región Antártica, en donde el área de la región con adelgazamiento ha llegado a tener 30 millones de kilómetros cuadrados aproximadamente, alcanzando así en sus bordes la parte sur de nuestro país. Durante la primavera austral de 2005, en la ciudad de Río Gallegos, se desarrolló la primera campaña de mediciones intensivas de parámetros atmosféricos denominada SOLAR (Stratospheric Ozone Lidar of Argentina) realizada por la División Lidar del CEILAP. En la misma se midieron perfiles de ozono utilizando la técnica lidar de absorción diferencial (DIAL), pudiéndose registrar un total de 29 mediciones durante el periodo agosto – noviembre de 2005, cinco de ellas coincidentes con reducción significativa del contenido total de ozono. En el presente trabajo, se presenta un análisis cualitativo de las mismas que permite visualizar las zonas de la estratosfera que más fueron afectadas por el paso del vórtice polar. La utilización de un sistema de coordenadas cuasi-conservativo (latitud equivalente, nivel isentrópico) permitió realizar la selección de los días dentro de esta campaña de medición que estuvieron afectados por el paso del vórtice polar Antártico que contiene al agujero de ozono.The thinning of the ozone layer over the South Pole of our planet is a seasonal phenomenon that from the decade of the 80’s is developed every year during spring time. The same one has its Maxima expression on the Antarctica region, in where the area of the region with ozone depletion has gotten to have 30 million of square kilometers approximately, thus reaching in its edges the South part of our country. During the austral spring of 2005, in the Río Gallegos city, the first campaign of intensive measurements of atmospheric parameters was developed. The same is named SOLAR (Stratospheric Ozone Lidar of Argentina) and is held by the Lidar Division of the CEILAP. We measured ozone profiles using the differential absorption lidar technique (DIAL), being able to register a total of 29 measurements during the period August - November of 2005, five of them coincident with significant reduction of the total ozone content. In the present work, a qualitative analysis of the same ones appears that allows to visualize the zones of the stratosphere which they were more affected by the passage of the polar vortex. The use of a quasi-conservative system of coordinates (equivalent latitude, isentropic level) allowed to make the selection of the days within this campaign of measurement that were affected by the passage of the Antarctic polar vortex that contains to the ozone hole.Fil: Wolfram, Elian Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; ArgentinaFil: Salvador, Jacobo Omar. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pallotta, Juan Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; ArgentinaFil: D´Elia, R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; ArgentinaFil: Pazmiño, A.. Service D’Aeronomie; ArgentinaFil: Godin Beeckmann, S.. Service D’Aeronomie; ArgentinaFil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación en Láseres y Aplicaciones; Argentin

Roller-Crimping As An Alternative To Incorporation Of Agro-Ecological Service Crops Changes Nitrogen Dynamics In Organic Cabbage Production Under Northern And Western European Conditions

Agro-ecological service crops (ASCs) are used to improve organic vegetable production in terms of weed suppression, nitrogen (N) recycling, or addition of N through symbiotic N2 fixation by legumes. Full incorporation (FI) of ASCs is commonly conducted to terminate ASCs, but alternative termination can be obtained by roller-crimping (RC) in reduced tillage systems. Field experiments were conducted in Estonia, Denmark, and at three locations in Belgium during two growing seasons (autumn 2015-2017) to investigate the effect of ASC termination method (FI and RC) and ASC species (pea, pea/cereal mixtures and cereals), compared with a bare soil control, on soil mineral N content, cabbage yield and N accumulation. Cabbage yield and N accumulation were reduced under RC compared to BS and FI in a majority of cases mainly due to reduced soil mineral N availability, in some cases owing to a later ASC termination time. Furthermore, slower mineralisation of soil organic matter and ASCs at the soil surface contributed to the yield reduction under RC as compared with FI. Cabbage yield could be maintained under RC at standard fertilisation rate following pea ASC in Denmark. The RC system needs further investigation to improve N availability to the succeeding crop before it can be implemented in organic vegetable production