Recensies

Alexander Mauro Ramseger

Einsatzfähigkeit von Gammadetektoren zum Nachweis des illegalen Transports von durch Containerladung abgeschirmter radioaktiver Substanzen

The topic of this research project is the detection of illicit trafficking of radioactive material inside of cargo containers. The currently used radiation portal monitors (RPM) at border crossings are not sufficient due to two effects which often occur during operation: false positive and false negative alarms. In case of false positive an alarm is given in the absence of radioactive material (or natural and harmless radioactive substances are classified as relevant anthropogenic material). In the second case, false negative, radioactive material with high risk potential is not detected. Because of these two effects, more advanced detections systems and other technical efforts are desirable. The expected increase of cargo container flow and special security programs like the Mega Port Initiative are demanding more reliable detection systems. Main focus of research project: This research project focuses on the applicability of spectrometric gamma detection systems in general. Regardless whether currently used, advanced detectors or hypothetic gamma detectors, all need a certain amount of gamma radiation to afford the identification of characteristic peaks. The overall problem is that the emitted gamma radiation is attenuated and has to be discriminated from the radiation background. One has to consider that the attenuation of radiation depends on the energy, and that often in the lower part of the energetic spectrum a higher background occurs. This leads in particular to a larger decrease of detection probability of radionuclides in the lower part of the energy spectrum. One can assume that even with high ambitioned efforts only a small progress in detection efficiency will be achieved because the marginal improvements approach physical limitations that cannot be overcome. The first part of the research project consisted of measurements with portal monitors and, in comparison, smaller spectrometric detectors. This was done in order to get an overview on realistic measurement conditions on frequently occurring radioactive substances and on minimal detectable activities. The second part is a simulation of portal monitors for gamma radiation. This is done to simulate gamma spectra of radionuclides inside cargo containers transported through a portal monitor. Measurements: Measurements were conducted at the cargo container checkpoint of the German Customs Office at the Hamburg Harbor. At this checkpoint a radiation portal monitor (RTM 910, produced by Mirion Technologies) has been installed. The RTM 910 is capable of neutron and gamma detection with a low energy-resolution. To detect the gamma radiation plastic scintillators are used. The RTM 910 has detectors on both sides of an incoming street to the checkpoint. The distance between the two detector parts is six meters and the cargo containers are transported through this portal monitor with an average velocity of 30 km/h. In the field experiment 30 to 40 cargo containers were controlled per hour. In this time approximately three alarms per hour were given. To examine what kind of radionuclides caused these alarms, it was necessary to analyze spectra of the radiation when such an alarm occurred. For the identification of the radioactive substances two other gamma detectors were used in addition to the RTM 910. One detector (ReGeM, produced by Canberra) was a high-purity-germanium detector with an energy resolution of less than 2 keV (e.g. 0,3% at 662 keV). The other detector (Spir Ident, produced by Mirion Technologies) is based on sodium-iodide and has an energy resolution of about 10 keV. The idea was to take spectra exactly at the time an alarm was given by the RTM 910 and to identify the alarm causing radionuclides by analyzing the spectra. It was possible to identify radionuclides in the spectra that were simultaneously recorded to RTM 910 alarms. All the detected radionuclides are naturally occurring. Simulations: In order to estimate the physical limitations and the remaining room for improvement of RPM, simulations with MCNP were conducted following the above mentioned measurements under field conditions. The best working detection conditions were determined studying the application of sodium-iodide and plastic scintillators in an RPM. The simulated RPMs were based on plastic scintillators and sodium-iodide. In the scenario certain radionuclides (e.g. Cs-137) were located in cargo containers. The containers were inspected with an RPM. The radiation of the nuclides was attenuated by different types of cargo (3) filled in the containers. These cargo types were derived from statistics of US-American and German ports. Every cargo type is related to a certain amount of cargo containers imported and exported. The radiation background was simulated as well to determine the minimum detectable activities. The room for improvement was evaluated regarding the measurement time and the number of used detectors in relation to a certain amount of sufficiently inspected containers. Since every cargo type is related to a certain percentage of imported and exported cargo containers, the room for improvement can be estimated related to a certain amount of containers which are inspected sufficiently. Most of this work was conducted during a research term at the Lawrence Livermore National Laboratory. (orig.)

Quelle: Energy Technology Data Exchange (ETDE) : DE11FF082

Alla Gatz

Was lehrt "Unser Charly"?

Eine Untersuchung des pädagogischen und ethischen Wertes einer Fernsehserie für Schulkinder

Diese Arbeit beschäftigt sich mit einer TV-Serie, die auf die Unterhaltung der ganzen Familie zugeschnitten ist: ”Unser Charlie”. Das Besondere an dieser Serie ist ein Schimpanse namens ”Charly”, der in jeder Folge mitspielt und stets in das Geschehen verwickelt ist. ... Mit Hilfe der vorliegenden Untersuchung soll der Frage nach dem Nutzen dieser TV-Serie nachgegangen werden. Dem ZDF zufolge hat die Serie, neben der unterhaltenden Funktion, auch die Vermittlung von naturkundlichem Wissen für Kinder und Jugendliche zum Ziel. ... Das Hauptanliegen [der Arbeit besteht darin], herauszufinden, wie sich die Serie auf Lernprozesse und den Erwerb von Wissen bei Kindern auswirkt. Damit soll am Ende der Untersuchung möglich werden, den pädagogischen Wert der Serie einzuordnen. Der zweite wichtige Punkt, mit dem sich die Arbeit befasst, ist der ethische Wert der TV-Serie ”Unser Charly”. (DIPF/Orig.)

Quelle: Informationssystem Medienpädagogik (ism)

Volker Peinelt, Ute Rademacher, Ute Meusel

Qualitätsmanagement-Leitfaden für Ausgabe- und Aufbereitungsküchen.

In Ganztagsschulen und Kindertagesstätten.

Um Schulen und Kindertagesstätten die praktische Umsetzung der vielfältigen Anforderungen an den Verpflegungsbereich zu erleichtern, hat die AG Schulverpflegung der Hochschule Niederrhein einen Qualitätsmanagement-Leitfaden für Ausgabe- und Aufbereitungsküchen entwickelt. Dieser kann nun über den Huss-Shop bezogen werden. Der Leitfaden ist eine Hilfestellung zur praktischen Gestaltung und systematischen Verbesserung im Bereich der Aufbereitung oder Ausgabe in der Schule oder Kita. Mit Hilfe des detaillierten Leitfadens können Anforderungen an eine gute Verpflegung Schritt für Schritt umgesetzt werden. Es werden konkrete, verständliche Handlungsanweisungen für den operativen Bereich gegeben und durch knapp gehaltenen, theoretischen Ausführungen ergänzt. Im Anhang werden diverse Formblätter und Dokumentationslisten, u. a. zur HACCP-Kontrolle, zur Verfügung gestellt.

Quelle: Zeitschrift: Schülermenue 3/2011 Seite 5

Daniele Bencivinni

Quantengravitation

Über die Entität gravitationserzeugender Wechselfelder und der Elementarfelder der Quantenelektrodynamik

The chapters about the propagation of the electromagnetic field, its properties in view of the propagation in space, the accompanying momentum, its kinetic energy and its mass-equivalent distribution of the total energy coupled to the relativistic mass represent today known and scientifically for a long time acknowledged as well as proved description of each phenomena. They are successively in a mathematically simple way formally listed and explained. The fundamental results of quantum mechanics, the quantum-mechanical momentum, Planck´s action quantum etc. are also presented in a simplified way. Also the essential forms of special relativity theory concerning the propagation of energy and momentum are presented. In a last setpit is checked, whether a possible common entity between the listed scientific experiences can be established. Possible explanation approaches on the described connections and the subsequent results are presented. If the gravitational waves are interpreted as quantized electromagnetic quantum waves, as matter waves, which can be assigned to a mass in the sense of Louis de Broglie and are for instance detectable as electron waves, by means of the relativistic quantum-mechanical spatial radiation gravitation could be described. So the ´´quantum-mechanical wave´´ could be responsible for the generation of mass via the interaction of elementary quantum fields. The propagation of one of these as mass appearing interaction of bound quantum fields can carry a conventional momentum because of its kinetic energy. The interaction in the Bose-Einstein condensate shows that the cooled rest mass exhibits the picture of a standing wave, the wave front of which propagates into the space. Because of the massive superposition of interference pattern warns the gravitational respectively matter wave can no more be isolated. A spatial radiation is however possible. Matter can generate a radiation in front of the inertial mass (quantum waves). If it succeeds to describe gravitation by means of a quantum-mechanical spatial radiation, then a physically foundable common entity of gravitation and quantum fields succeeds. This proof is performed.

Quelle: ETDE - Energy Database-production no.:DE11FA011

Rudolf Röttger, Robert Knight, Wilhelm Foissner † (Eds.)

A Course in Protozoology

Second revised edition

Books focused on the more practical aspects of the teaching of unicellular eukaryote biology are not common, especially in the English-speaking world. It is thus very pleasing to see the publication of "A Course in Protozoology," an updated and modified translation from the German "Praktikum der Protozoologie" published in 1995 that focuses on just that: the more hands-on aspects of the teaching of the biology of these organisms.
The editors made a big effort to cover as wide a ränge of protozoans as possible, and as a consequence, the book includes chapters not only on common things like ciliates (six chapters), dinoflagellates (two chapters) or thecate and naked amoebae (three chapters), but also on more "difficult" groups like radiolarians, kinetoplastids, diplomonads or foraminiferans. In addition some algae are also covered, for example diatoms, chrysophytes and euglenids. In the preface the editors explain their choice of the word "protozoology" instead of "protistology" for the title of the book and say that readers of a textbook entitled "A course in protistology" would expect to find more unicellular algae and lower fungi included. They are perhaps right, but it has to be said that they akeady walked a large part of the road to transform this protozoological book into a protistological one; the addition of only a few chapters (green algae, slime moulds, oomycetes, cryptomonads/haptophytes come to mind) would neatly finish the job. This is something that they could Because there really should be more editions of this excellent book. Its main contribution is that it provides detailed practical information and an incredible amount of tricks about where to obtain and how to prepare unicellular eukaryotes in order to observe them and show them to students. You want to find kineto plastids in the wild? Look in sheep keds or in the blood of eels, which you can get in any fish shop. How about coccidian oocysts? Use mice or chicken faeces and float them in a "dense solution" whose composition is explained in detail. How do you observe pinocytosis in a live Amoeba proteusl You put it in a 1:10 solution of egg white. Can you encourage Noctiluca cultures to bioluminesce when you need them to? To a degree, yes, you add a bit of formaldehyde to the sample and the culture may go out in a blaze of light. Where do you find pelobionts? Suctorians, chonotrichs? How do you remove the plasma membrane of thecate dinoflagellates? How do you stain their thecal pates? And ciliate alveolar boundaries? And chrysophyte siliceous structures? How do you maximize the survival time of parabasalian symbionts outside their termite hosts?
The illustrations are excellent. All chapters contain profuselylabeled drawings not only of organisms, but also of important as pects of their biology, things like life cycles, ways of feeding or nomenclatural schematics of thecal or skeletal parts that help greatly in the interpretation of what is being seen. Photographs are a great asset to this, and many chapters additionally contain an assortment of images obtained not only through light microscopy but also through SEM or TEM.
I don´t want to finish without mentioning a quirky but very useful feature of the book. The editors obtained the help of Prof. Alfred Hoffmann, a now late Linguist at the University of "Bochum, to gu through the index^andrnarkThe accented Vöwel in the Latin names of all the organisms included. I am going to go on a limb and suggest that the correct pronunciation of Latin names is not a strength of the majority of English-speaking protozoologists, and so even though some may not wish to modify deeply-held convictions about the proper pronunciation in English of Latin names, the book manages to at least inform them of die error of their ways. A commendable effort. Negative comments? Very few. In places the translation to English retains too much of a German tinge and the reading flow •suffers. Some chapters are perhaps a bit too descriptive and don´t emphasize enough things that students can actually do with the organisms that they collect.Yet in spite of all this, the main thing that I find myself wishing for is chapters on the protist groups that were not covered. I think that in itself is a strong comment of the chapters that did get written.
As the teacher of a course in protistology, I have already (successfully!) used a lot of the information contained in the book, and not only that, but I have been inspired to develop whole new labs based on the information presented (vampyrellids feed ing on filamentous algae, anyone?) I can´t think of a better endorsement than that. This is very good book. Go buy it.
—JUAN F. SALDARRIAGA, Department of Botany, 6270 University Boulevard, Vancouver, BC V6T ITA, Canada.

Quelle: Journal of Eukaryotic Microbiology; 2011; Seite 272

H. Martin Hövel

Elektrodynamik dünner Metallfilme am Isolator-Metall-Übergang

Aim of this thesis was to study films near the percolation limit and over a wide spectral range. For this under UHV conditions thin gold layers were deposited on a silicon substrate with a 200 nm thick SiO{sub 2} layer. The layer densities of the gold films evaporated with a rate of 0.9 Aa/min vary in a small range around the percolation limit. By means of a simultaneous fit to the reflection, transmission, ellipsometry, and DC conductivity measurements the properties of the gold films could be determined over the whole frequency range from DC to the ultraviolet. By this near the percolation limit a dielectric anomaly was observed, which influences strongly the optical behaviour of the gold layers.

Quelle: ETDE - Energy Database-production no.: DE11G3763

Matteo Mariantoni

New Trends in Superconducting Circuit Quantum Electrodynamics: Two Amplifiers, Two Resonators, and Two Photons

A Not So Short Introduction to Quantum Circuits and Signals

The book contains the following chapters: general chapters on light-matter interaction, the quantum circuit toolbox: an optical table on a chip, correlation homodyne detection at microwave frequencies: experimental setup and experimental results; two-resonator circuit QED; a superconducting quantum switch; two-resonator circuit QED: generation of Schroedinger cat states and quantum tomography; two-dimensional cavity grid for scalable quantum computation with superconducting circuits; circuit QED experiments with superconducting flux Qubits.

Quelle: ETDE - Energy Database-production no.:DE11G4535

Lisandro Buljubasich Gentiletti

Nuclear Magnetic Resonance as a Tool for On-Line Catalytic Reaction Monitoring

The work presented here consists in a combination of different aspects of Nuclear Magnetic Resonance, focused on providing a, reliable tool for the optimization of chemical processes, via the on-line monitoring of catalytic reactions. For that purpose, the following decomposition in the presence of metal containing porous media as a catalyst, was studied as a model reaction: 2H₂ O₂ (liquid) —> 2HO + O₂ (gas). The results presented along this work include: the feasibility of using the time dependence of the effective diffusion coefficient in the vicinity of the catalysts to monitor the decomposition with relatively high temporal resolution for seA-eral hours; the possibility of making use of the influence of two-site chemical exchange between protons in water and hydrogen peroxide on the transverse relaxation rate, together with p#, to obtain a quantification of the H₂ O₂ concentration during the reaction, in the liquid surrounding the catalyst; the use of the chemical exchange as a source of contrast in NMR Imaging, providing a tool for monitoring the reaction with spatial resolution inside the porous particle. Possible extensions of the results and experiments to different kind of samples and set ups are suggested at the end of the work.(orig.)

Quelle: FIZ Karlsruhe