Preliminary results from fatigue tests with reference to operational statistics

Simple elements were subjected to repeated loads of variable ampliture, chosen in such a way that they may be regarded as approximations to the operational loads (gust and maneuver) experienced by an airplane. The effect of varying some parameters was investigated briefly. Some discussion is given of the question whether a design according to current (1938 German) requirements for static strength is adequate from the fatigue point of view, and existing requirements on fatigue strength are compared

Radiation And Annealing Characteristics Of Neutron Bombarded Silicon Transistors

Operating a silicon planar epitaxial transistor in the inverse configuration allows one to demonstrate clearly the importance of the neutron-induced base current component and its degradation of the emitter efficiency, and, because of the much larger depletion layer, to compute a volume dependent damage constant applicable to all silicon p-n junctions. The importance of minimizing the absolute change versus relative change in radiation hardening studies is clearly illustrated. Surface effects were found to be significant for transistors mounted in gas-filled cans. The diffusion potential was predicted, on theoretical grounds, to vary with neutron fluence, and the theory was experimentally confirmed. Isochronal and isothermal annealing data were obtained for the inverse configuration and from these data, it is concluded that the neutron-induced defect centers are field dependent. Copyright © 1968 by The Institute of Electrical and Electronics Engineers, Inc

COLOPHON 2013

International audienceIn 2010 the Mimar Sinan University of Istanbul started a research project on the Ionian town of Colophon which is conducted in close collaboration with the University of Vienna [1]. It aims at the exploration of the ancient urban area as well as on the distribution of the necropoleis. For the campaign of the year 2013 the Austrian research team concentrated on the following topics [2]. 1. Survey in the area of the ancient city This year, the main focus of the investigations in the area within the fortification walls was laid on the exploration of the urbanistic organisation of the city by magnetic survey and by ground penetrating radar. For this purpose two areas were chosen. The first area consisted of fields in the plain between the brooks Kabaklidere and Kurudere in the north eastern quarters of the ancient city. Here the existence of houses has been proven by excavations by the museum of Izmir about 10–15 years ago. The remains of walls were also visible in several trenches opened by illegal diggers both on the plains and in the forested area near the slopes of the surrounding hills. The geophysical prospection confirmed the assumed existence of several buildings and streets in the area. In addition we conducted an extensive survey in adjacent fields and collected pottery from the holes dug by illegal diggers. The finds included roof tiles and a small amount of pottery with a chronological range from the 6 th to the 4 th c. BC. A detailed documentation of the present land-use and land-division of this area, already begun in 2012, was continued with the aim of a diachronical understanding of the landscape's historical development. This included the description of modern features in the fields as well as interviews with owners and tenants. The second area chosen for a geophysical prospection is situated to the south of the Halil Ağa Tepesi, where W. Höpfner proposed to locate the ancient agora [3]. Both magnetic survey and ground penetrating radar prospections were carried out here. Further examination of the data is currently being carried out. The exemplary geophysical prospection will give important insights into the organisation and layou

COLOPHON 2013

International audienceIn 2010 the Mimar Sinan University of Istanbul started a research project on the Ionian town of Colophon which is conducted in close collaboration with the University of Vienna [1]. It aims at the exploration of the ancient urban area as well as on the distribution of the necropoleis. For the campaign of the year 2013 the Austrian research team concentrated on the following topics [2]. 1. Survey in the area of the ancient city This year, the main focus of the investigations in the area within the fortification walls was laid on the exploration of the urbanistic organisation of the city by magnetic survey and by ground penetrating radar. For this purpose two areas were chosen. The first area consisted of fields in the plain between the brooks Kabaklidere and Kurudere in the north eastern quarters of the ancient city. Here the existence of houses has been proven by excavations by the museum of Izmir about 10–15 years ago. The remains of walls were also visible in several trenches opened by illegal diggers both on the plains and in the forested area near the slopes of the surrounding hills. The geophysical prospection confirmed the assumed existence of several buildings and streets in the area. In addition we conducted an extensive survey in adjacent fields and collected pottery from the holes dug by illegal diggers. The finds included roof tiles and a small amount of pottery with a chronological range from the 6 th to the 4 th c. BC. A detailed documentation of the present land-use and land-division of this area, already begun in 2012, was continued with the aim of a diachronical understanding of the landscape's historical development. This included the description of modern features in the fields as well as interviews with owners and tenants. The second area chosen for a geophysical prospection is situated to the south of the Halil Ağa Tepesi, where W. Höpfner proposed to locate the ancient agora [3]. Both magnetic survey and ground penetrating radar prospections were carried out here. Further examination of the data is currently being carried out. The exemplary geophysical prospection will give important insights into the organisation and layou

Laser Tracker Test Facility at SLAC - Progress Report

Physics experiments at SLAC require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser Tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. In order to improve and get a better understanding of laser tracker measurement tolerances we extended our laboratory with a rotary calibration table (Kugler GmbH) providing an accuracy of better than 0.2 arcsec. This paper gives an overview of the calibration table and its evaluation. Results of tests on two of our Laser Trackers utilizing the new rotary table as well as the SLAC interferometer bench are presented

On a Tree and a Path with no Geometric Simultaneous Embedding

Two graphs $G_1=(V,E_1)$ and $G_2=(V,E_2)$ admit a geometric simultaneous embedding if there exists a set of points P and a bijection M: P -> V that induce planar straight-line embeddings both for $G_1$ and for $G_2$. While it is known that two caterpillars always admit a geometric simultaneous embedding and that two trees not always admit one, the question about a tree and a path is still open and is often regarded as the most prominent open problem in this area. We answer this question in the negative by providing a counterexample. Additionally, since the counterexample uses disjoint edge sets for the two graphs, we also negatively answer another open question, that is, whether it is possible to simultaneously embed two edge-disjoint trees. As a final result, we study the same problem when some constraints on the tree are imposed. Namely, we show that a tree of depth 2 and a path always admit a geometric simultaneous embedding. In fact, such a strong constraint is not so far from closing the gap with the instances not admitting any solution, as the tree used in our counterexample has depth 4.Comment: 42 pages, 33 figure

Depressed electron collector for the Gatling Gun Test Stand

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Marine Mammal Strandings

Since the 1980s, there has been growing concern about the health of marine mammal populations in coastal waters and in particular with respect to a decline in harbour porpoise (Phocoena phocoena) numbers. A variety of possible causes have been proposed including infectious diseases, changes in food supply, pollution and entanglement in fishing gear. Recent studies linking contaminant data with disease levels in cetaceans suggest that higher contaminant levels are generally found in animals with a higher number of diseases i.e. that chronic exposure to PCBs or trace metals negatively influences the health status of some cetacean species by predisposing individuals to mortality associated with infectious disease (Jepson et al., 1999; Siebert et al., 1999). The reverse may also be true, that high levels of disease may disable the animal to the extent that coping with contaminants is not possible and toxins accumulate. The potentially serious role of infectious disease was demonstrated by the phocine distemper epidemic of 1987, which killed approximately 18,000 common seals (Phoca vitulina) in the North Sea and adjacent waters (Kennedy, 1990) and by the subsequent morbillivirus epidemic in striped dolphins (Stenella coeruleoalba) in the Mediterranean sea (Domingo et al., 1990). Rejinders (1986) and Brouwer et al. (1989) demonstrated that feeding captive common seals with fish caught in highly polluted waters had deleterious effects on their health and there was speculation that pollution may have been a factor in the severity of these epidemics (Aguilar and Raga, 1990, Aguilar and Borrell, 1994, deSwart et al., 1994). Relatively little work on the health status and contaminant loadings in cetacean and pinniped populations in the Irish Sea has been undertaken to date (e.g., Morris et al., 1989, Law et al., 1995, Berrow et al., 1998a). Given the need for such data from relatively "high-medium" polluted waters (e.g., the Irish Sea) such a data collection programme is highly desirable. For a large number of cetacean and seal species, the only way to assess their health status and contaminant loadings, bar live capture and/or killing them, is through a Strandings Programme. Such programmes involve the recording and recovering of beach cast animals. Strandings programmes allow for some definition of the distribution of different species, but are primarily used to examine health status and to determine population parameters necessary for management decisions. Such programmes are imperative, as they allow top mammalian predators to be monitored and increase our knowledge of a number of biological parameters (for example, age, reproductive status, diet), parasites and contaminant loadings. Cause of death can reflect disease status and in the absence of observer programmes, can indicate fishing associated mortalities (by-catch).Funder: European Unio