More Flexible Damping Systems for Blades and Vanes

The blades and the vanes of aero engines are subject to very high thermo-mechanical loads. In some cases, an additional damping system is necessary to reach the lifetime goals. Commonly, damping systems based on energy dissipation due to friction are used, e.g. under platform dampers for blades and spring dampers for the vanes. These damping systems have some limitations: under platform dampers work well mostly for just one mode family, their effectiveness is limited relative to rotational speed (because of the associated contact forces) and is dependent on the excitation order. The spring dampers work well for more than one mode family but their effectiveness is limited concerning the available contact force (just one value). Additionally, the use of the spring dampers requires a significant, sometimes suboptimal design change of the vane cluster. In this paper, some alternative damping systems are introduced and analyzed. All these new systems offer additional possibilities for damping and give more design flexibility. Two of them: insert damping and rocking damping are also based on frictional energy dissipation. The third one, impulse mistuning, adopts a special kind of absorption and is based on the so called targeted energy transfer. The analytical results for the insert damping systems were presented previously in Borufka et al. (2009), while in this paper the experimental validation by shaker tests is shown. The rocking damping was not presented so far – to the knowledge of the authors. Impulse mistuning was first presented in: Hartung and Retze (2011) and Hartung et al. (2016). In this work, an overview of such damping systems and some additional information on the experimental validation of some impulse mistuning systems are presented

Paracrine and autocrine regulation of gene expression by Wnt-inhibitor Dickkopf in wild-type and mutant hepatocytes

BACKGROUND: Cells are able to communicate and coordinate their function within tissues via secreted factors. Aberrant secretion by cancer cells can modulate this intercellular communication, in particular in highly organised tissues such as the liver. Hepatocytes, the major cell type of the liver, secrete Dickkopf (Dkk), which inhibits Wnt/β-catenin signalling in an autocrine and paracrine manner. Consequently, Dkk modulates the expression of Wnt/β-catenin target genes. We present a mathematical model that describes the autocrine and paracrine regulation of hepatic gene expression by Dkk under wild-type conditions as well as in the presence of mutant cells. RESULTS: Our spatial model describes the competition of Dkk and Wnt at receptor level, intra-cellular Wnt/β-catenin signalling, and the regulation of target gene expression for 21 individual hepatocytes. Autocrine and paracrine regulation is mediated through a feedback mechanism via Dkk and Dkk diffusion along the porto-central axis. Along this axis an APC concentration gradient is modelled as experimentally detected in liver. Simulations of mutant cells demonstrate that already a single mutant cell increases overall Dkk concentration. The influence of the mutant cell on gene expression of surrounding wild-type hepatocytes is limited in magnitude and restricted to hepatocytes in close proximity. To explore the underlying molecular mechanisms, we perform a comprehensive analysis of the model parameters such as diffusion coefficient, mutation strength and feedback strength. CONCLUSIONS: Our simulations show that Dkk concentration is elevated in the presence of a mutant cell. However, the impact of these elevated Dkk levels on wild-type hepatocytes is confined in space and magnitude. The combination of inter- and intracellular processes, such as Dkk feedback, diffusion and Wnt/β-catenin signal transduction, allow wild-type hepatocytes to largely maintain their gene expression

Secondary Electron Yield Measurements of Fermilab's Main Injector Vacuum Vessel

We discuss the progress made on a new installation in Fermilab's Main Injector that will help investigate the electron cloud phenomenon by making direct measurements of the secondary electron yield (SEY) of samples irradiated in the accelerator. In the Project X upgrade the Main Injector will have its beam intensity increased by a factor of three compared to current operations. This may result in the beam being subject to instabilities from the electron cloud. Measured SEY values can be used to further constrain simulations and aid our extrapolation to Project X intensities. The SEY test-stand, developed in conjunction with Cornell and SLAC, is capable of measuring the SEY from samples using an incident electron beam when the samples are biased at different voltages. We present the design and manufacture of the test-stand and the results of initial laboratory tests on samples prior to installation.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012) 20-25 May 2012, New Orleans, Louisian

Causes, coping, and culture : a comparative survey study on representation of back pain in three Swiss language regions

Introduction: This study intends to contribute to a research tradition that asks how causal attributions of illnesses affect coping behavior. Causal attributions are understood as the most important element of illness representations and coping as a means to preserve quality of life. The issue is applied to a condition so far often neglected in research on illness representations-back pain-and a third concept is added to the picture: culture. Aim: The aim of this study is (a) to explore the causal factors to which persons with back pain attribute the further course of their illness, (b) to find out whether the attributed causes are predictors of coping maxims, and (c) to find out whether cultural factors affect attributions and coping and moderate the relationship between the two. Methods: A total of 1259 gainfully employed or self-employed persons with recent episodes of back pain were recruited in the three language regions of Switzerland. They were asked to complete a structured online interview, measuring among many other variables attributed causes, coping maxims, and affiliation to one of the Swiss micro-cultures (German-, Frenchor Italian-speaking). Results: Attributed causes of the illness that can be influenced by a patient go along with more active coping styles. Cultural affiliation impacts on coping maxims independently, but culture moderates the relationship of attributed causes and coping maxims only in two of twenty possible cases. Implications: The results show that cultural differences can be analytically incorporated in the models of illness representations. Results may help to improve healthcare providers' communication with patients and plan public health campaigns. The approach to micro-cultural differences and the substantive relationships between alterability of causes and activity in coping may help the further development of models of illness representations. \ua9 2013 Schulz et al

Ixodes ricinus spirochete and European erythema chronicum migrans disease.

From three endemic locations of erythema chronicum migrans disease in North Rhine-Westphalia, Germany, we recovered 19 isolates of a spirochete from Ixodes ricinus ticks. The infection rate in adult ticks was 16 percent. The isolated spirochete is immunologically related to the Ixodes dammini spirochete, Borrelia duttoni, and Treponema pallidum. Using indirect immunofluorescence, the sera of 90 patients with erythema chronicum migrans disease showed antibody titers against the isolated spirochete, which correlated with the clinical course. Similarly, antibodies were demonstrated in the sera of 21 patients with acrodermatitis chronica atrophicans. These results suggest an etiologic role for the Ixodes ricinus spriochete in European erythema chronicum migrans disease

The cool atmospheres of the binary brown dwarf eps Indi B

We have imaged $\epsilon$ Indi B, the closest brown dwarf binary known, with VISIR at the VLT in three narrow-band mid-infrared bandpasses located around 8.6$\mu$m, 10.5$\mu$m and 11.3$\mu$m. We are able to spatially resolve both components, and determine accurate mid-infrared photometry for both components independently. In particular, our VISIR observations probe the NH$_3$ feature in the atmospheres of the cooler and warmer brown dwarfs. For the first time, we can disentangle the contributions of the two components, and find that % our photometry of $\epsilon$ IndiBb is in good agreement with recent ``cloud-free'' atmosphere models having an effective temperature of $T_\mathrm{eff}=800$ K. With an assumed age of 1 Gyr for the $\epsilon$ Indi system, component Ba agrees more with $T_\mathrm{eff} \approx 1100$ K rather than with $T_\mathrm{eff}=1200$ K, as suggested by SPITZER spectroscopic observations of the combined $\epsilon$ Indi B system (Roellig et al., 2004). Even higher effective temperatures appear inconsistent with our absolute photometry, as they would imply an unphysical small size of the brown dwarf $\epsilon$ IndiBa.Comment: 4 pages, 2 figure

H1N1 influenza pandemic in Italy revisited : has the willingness to get vaccinated suffered in the long run?

Background. The aim of the study is to assess the long-term secondary effects of personal experience with the H1N1 pandemic of 2009/2010 and the perception of the institutional reaction to it on Italians\u2019 willingness to get vaccinated in case of a novel influenza pandemic. Design and Methods. We conducted 140 face-to-face interviews in the Registry Office of the Municipality of Milan, Italy, from October to December 2012. Results. Willingness to get vaccinated during a novel influenza pandemic was best predicted by having been vaccinated against the seasonal flu in the past (OR=5.18; 95%CI: 1.40 to 19.13) and fear of losing one\u2019s life in case of an infection with H1N1 (OR=4.09; 95%CI: 1.68 to 9.97). It was unaffected by the assessment of institutional performance. Conclusions. The findings of this study do not point to long-term secondary effects of the institutional handling of the H1N1 pandemic. The results highlight the fact that behavioural intention is not the same as behaviour, and that the former cannot simply be taken as an indicator of the latter

Arbeitsmotivation: Expertise

Die "Expertise" wertet verschiedene Intervallstudien aus dem Zeitraum 1984 bis 1988 in der DDR zur "Entwicklung der Leistungsbereitschaft junger Werktätiger" aus, um Hinweise für die künftige Arbeit des Jugendverbandes FDJ zu geben. Dargestellt werden die die Leistung beeinflussenden Faktoren und Motive (Anspruchsniveau, Tätigkeitsziele, Leistungsanreize in Form von Geld oder Anerkennung, Zukunftsorientierung und Lebenspläne). An Folgerungen werden u. a. genannt: "Hauptansatz für alle ideologischen Aktivitäten des Jugendverbandes zur Förderung hoher Leistungsbereitschaft sollte die Entwicklung langfristiger Ideale sein." Ferner werden zusätzliche Initiativen zur Erhöhung der Leistungsbereitschaft und zu entsprechendem Engagement gefordert, allerdings unter Einhaltung des Prinzips der Freiwilligkeit. Außerdem sollen die finanziellen Anreize ("Konto junger Sozialisten") in den Betrieben oder den FDJ-Gliederungen verbessert werden. (psz

Prior family communication and consent to organ donation: Using intensive care physicians' perception to model decision processes

Generally, the Swiss hold favourable attitudes to organ donation, but only few carry a donor card. If no card is found on a potential donor, families have to be approached about donation. The aim of this paper is to model the role that some family communication factors play in the family decision to consent or not to organ donation by a brain dead relative. Information was gathered in face-to-face interviews, using a questionnaire and recording open answers and comments. Eight heads of intensive care units (ICU) of Swiss hospitals and one representative from Swisstransplant were interviewed. Questions asked respondents to estimate the prevalence and effect of communication factors in families facing a decision to consent to donation. Answers were averaged for modelling purposes. Modelling also relies on a previous representative population survey for cross-validation. The family of the deceased person is almost always approached about donation. Physicians perceive that prior thinking and favourable predisposition to donation are correlated and that the relatives' predisposition is the most important factor for the consent to donation, up to the point that a negative predisposition may override an acknowledged wish of the deceased to donate. Donor cards may trigger family communication and ease the physicians' approach to family about donation. Campaigns should encourage donate-willing people to talk to their families about it, make people think about organ donation and try to change unfavourable predispositions