Photoconductivity of polymeric dibenz [b,i] 1,4,8,11-tetraaza [14] annulenato (μ-pyrazin)iron(II) [Fetaa(pyz)]n

Summary Results of experiments on dark- and photoconductivity of polymeric dibenz[b,i] 1,4,8,11-tetraaza[14]annulenato(-pyrazin) iron(II) [Fetaa(pyz)]_n are described. By studying the dependence of photoconductivity on electric field, intensity and wavelength it is shown that photogeneration of charge carriers occurred at short wavelengths by an Onsager mechanism and in the near-infrared region by a photoinjection process from the electrodes.Dedicated to Prof. Dr. G. Manecke on the occasion of his 70th birthdayThe authors would like to thank the Volkswagen Foundation for financial support.     

FEM investigation and thermo-mechanic tests of the new solid tungsten divertor tile for ASDEX Upgrade

A new solid tungsten divertor for the fusion experiment ASDEX Upgrade is under construction at present. A new divertor tile design has been developed to improve the thermal performance of the current divertor made of tungsten coated fine grain graphite. Compared to thin tungsten coatings, divertor tiles made of massive tungsten allow to extend the operational range and to study the plasma material interaction of tungsten in more detail. The improved design for the solid tungsten divertor was tested on different full scale prototypes with a hydrogen ion beam. The influence of a possible material degradation due to thermal cracking or recrystallization can be studied. Furthermore, intensive Finite Element Method (FEM) numerical analysis with the respective test parameters has been performed. The elastic–plastic calculation was applied to analyze thermal stress and the observed elastic and plastic deformation during the heat loading. Additionally, the knowledge gained by the tests and especially by the numerical analysis has been used to optimize the shape of the divertor tiles and the accompanying divertor support structure.This paper discusses the main results of the high heat flux tests and their numerical simulations. In addition, results from some special structural mechanic analysis by means of FEM tools are presented. Finally, first results from the numerical lifecycle analysis of the current tungsten tiles will be reported.     

The ASDEX upgrade digital video processing system for real-time machine protection

This paper describes the design, implementation, and operation of the Video Real-Time (VRT) diagnostic system of the ASDEX Upgrade plasma experiment and its integration with the ASDEX Upgrade Discharge Control System (DCS). Hot spots produced by heating systems erroneously or accidentally hitting the vessel walls, or from objects in the vessel reaching into the plasma outer border, show up as bright areas in the videos during and after the reaction. A system to prevent damage to the machine by allowing for intervention in a running discharge of the experiment was proposed and implemented. The VRT was implemented on a multi-core real-time Linux system. Up to 16 analog video channels (color and b/w) are acquired and multiple regions of interest (ROI) are processed on each video frame. Detected critical states can be used to initiate appropriate reactions – e.g. gracefully terminate the discharge. The system has been in routine operation since 2007.     

The material basis for reduced mechanical properties in oim mice bones

Osteogenesis imperfecta (OI), a heritable disease caused by molecular defects in type I collagen, is characterized by skeletal deformities and brittle bones. The heterozygous and homozygous oim mice (oim/+ and oim/oim) exhibit mild and severe OI phenotypes, respectively, serving as controlled animal models of this disease. In the current study, bone geometry, mechanics, and material properties of 1-year-old mice were evaluated to determine factors that influence the severity of phenotype in OI. The oim/oim mice exhibited significantly smaller body size, femur length, and moment of area compared with oim/+ and wild-type (+/+) controls. The oim/oim femur mechanical properties of failure torque and stiffness were 40% and 30%, respectively, of the +/+ values, and 53% and 36% of the oim/+ values. Collagen content was reduced by 20% in the oim/oim compared with +/+ bone and tended to be intermediate to these values for the oim/+. Mineral content was not significantly different between the oim/oim and +/+ bones. However, the oim/oim ash content was significantly reduced compared with that of the oim/+. Mineral carbonate content was reduced by 23% in the oim/oim bone compared with controls. Mineral crystallinity was reduced in the oim/oim and oim/+ bone compared with controls. Overall, for the majority of parameters examined (geometrical, mechanical, and material), the oim/+ values were intermediate to those of the oim/oim and +/+, a finding that parallels the phenotypes of the mice. This provides evidence that specific material properties, such as mineral crystallinity and collagen content, are indicative and possibly predictive of bone fragility in this mouse model, and by analogy in human OI.     

有限元方法计算J积分

本文讨论了有限元方法计算Ｊ积分，并依据能量区域积分方法编制了计算机程序，通 过对ＣＣＴ试块的计算表明程序可靠准确。     

Ambient media for peripheral information display

In our everyday lives, we use surrounding living and working environments to arrange physical information artefacts such as books, pictures and calendars. However, when it comes to consumption of computer-based information, this is almost entirely based on attending to screens that separate us from our surroundings. In this paper, we explore the augmentative use of non-computer artefacts in our surroundings for peripheral display of digital information. We discuss system integration of such ambient media, the mapping of information to ambient media, and issues of flexibility and user control. Ambient media have been in everyday use in our work environment, and we report observations from which we conclude their utility as extensions to our digital information spaces.     

Oral contraceptive use and vaginal candida colonization

Fungal vaginal infections/colonisations can be divided into a symptomatic vaginal candidiasis and an asymptomatic vaginal Candida-carriage. The latter seems to be a predisposing factor for the development of a symptomatic vaginal candidiasis. The fungal organism isolated most frequently is Candida albicans, followed by Candida glabrata, which was previously also known as Torulopsis glabrata. To a lower extend, other Candida species such as Candida tropicalis and Candida krusei can be prevalent in the vulvovaginal region. Predisposing factors for vaginal candidiasis are gravidity, diabetes mellitus or a therapy with immunosuppressive agents. Also gestagenes showed to be a pre-disposing factor for vaginal candidiasis. Divergent results concerning the predisposition to vaginal candidiasis or colonisation due to oral contraception have so far been reported. Therefore we performed a study with two healthy collectives of female volunteers (n = 2 x 60) which were different concerning the taking of oral contraceptives. Overall, in 17% of the subjects (20/120) yeast could be cultured out of the vaginal secretions. There was no evidence for a higher rate of Candida-colonisation in subjects taking oral contraceptives. Further, there was no evidence for a relationship between the length of the taking of oral contraceptives and the rate of vaginal yeast-carriage. Also the type of oral contraceptive (combination or sequential contraceptive) had no influence on the frequency of Candida-carriage. Candida albicans was the most prevalent yeast (16/20), followed by Candida glabrata (4/20).     

Premixed and nonpremixed generated manifolds in large-eddy simulation of Sandia flame D and F

Premixed and nonpremixed flamelet-generated manifolds have been constructed and applied to large-eddy simulation of the piloted partially premixed turbulent flames Sandia Flame D and F. In both manifolds the chemistry is parameterized as a function of the mixture fraction and a progress variable. Compared to standard nonpremixed flamelets, premixed flamelets cover a much larger part of the reaction domain. Comparison of the results for the two manifolds with experimental data of flame D show that both manifolds yield predictions of comparable accuracy for the mean temperature, mixture fraction, and a number of chemical species, such as CO₂. However, the nonpremixed manifold outperforms the premixed manifold for other chemical species, the most notable being CO and H₂. If the mixture is rich, CO and H₂ in a premixed flamelet are larger than in a nonpremixed flamelet, for a given value of the progress variable. Simulations have been performed for two different grids to address the effect of the large-eddy filter width. The inclusion of modeled subgrid variances of mixture fraction and progress variable as additional entries to the manifold have only small effects on the simulation of either flame. An exception is the prediction of NO, which (through an extra transport equation) was found to be much closer to experimental results when modeled subgrid variances were included. The results obtained for flame D are satisfactory, but despite the unsteadiness of the LES, the extinction measured in flame F is not properly captured. The latter finding suggests that the extinction in flame F mainly occurs on scales smaller than those resolved by the simulation. With the presumed β-pdf approach, significant extinction does not occur, unless the scalar subgrid variances are overestimated. A thickened flame model, which maps unresolved small-scale dynamics upon resolved scales, is able to predict the experimentally observed extinction to some extent.