Optimized Approach for Determination of the Solid Temperature in a Steam Turbine in Warm-Keeping-Operation

International audienceThe determination of the temperature distribution in the thick-walled components in steam turbines is increasing in relevance. Due to the growing share of volatile renewable power generation, power plants with a high flexibility and a high integral efficiency are required. e current operational conditions lead to high thermal stresses inside the heavy components and thus to a reduced lifetime. To improve the ability for a fast start-up, the steam turbine can be kept warm during a longer period of stand still. Therefore, information about the metal temperature inside the rotor and the casing are crucial. However, the temperature distribution of the inner casing and especially the rotor cannot be measured without high additional effort. us, a calculation model with sufficient accuracy and also manageable calculation effort is required. In the present work, a hybrid-numerical FEM and analytical-approach has been developed to calculate the solid body temperatures of a steam turbine in warm-keeping operation in a most efficient way. The presented model provides accuracy of nearly % compared with Conjugate-Heat-Transfer simulations with a simultaneously reduced calculation effort by a factor of more than

Test Rig for Applied Experimental Investigations of the Thermal Contact Resistance at the Blade-Rotor-Connection in a Steam Turbine

International audienceStudies have shown that in a pre-warming respectively warm-keeping operation of a steam turbine, the blades and vanes transport most of the heat to the thick-walled casing and rotor. Thereby, a bottle-neck arises at the connection between the blade root and the rotor. The contact heat resistance at these interfaces affects the temperature distribution and thus the thermal stresses in the rotor. The present paper introduces a thermal contact resistance test rig, which is designed to quantify the contact heat transfer at the blade-rotor-connection of a steam turbine. An uncertainty analysis is presented which proves that the average measurement uncertainties are less than one percent. In addition to the test rig, a numerical model of the specimen for the determination of the thermal contact resistance is developed and introduced. Results of several steady-state measurements under atmospheric and evacuated atmosphere using a highly temperature-resistant chromium molybdenum steel are shown. As a main influence parameter the contact pressure is investigated, which is affected by the rotational speed of the turbine. The investigations show a significant contact heat resistance especially at small contact pressures

Neues Tragseilfördersystem für den Stückguttransport

Forscher des Sächsischen Textilforschungsinstitutes und der Professur Fördertechnik haben gemeinsam mit der Industrie ein neues Zugmittel für den Stückguttransport entwickelt. Dieses Zugmittel basiert auf einem gewirkten Seil, in welches in definierten Abständen Stahlbolzen eingearbeitet sind. Zur Aufnahme des Fördergutes und zum Gleiten in einem Führungssystem werden auf die Bolzen Tragplatten aus Kunststoff geschnappt. Der Antrieb des Zugmittels erfolgt formschlüssig an den in einer definierten Teilung integrierten Bolzen. Das neue Zugmittel zeichnet sich durch eine erhöhte Kurvengängigkeit und Festigkeit aus

An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases

Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.Comment: 3 pages, 6 figures, submitted to Chem. Com

Photostress Recovery Time as a Potential Predictive Biomarker for Age-Related Macular Degeneration

Abstract Purpose: The purpose of this study was to assess recovery time following photostress and its association with age-related macular degeneration (AMD) cross-sectionally and longitudinally in an elderly population-based cohort. Methods: We analyzed photostress recovery time (PRT) and AMD in >1800 AugUR study participants aged 70+ years. On color fundus images from baseline and 3-year follow-up, presence of AMD was graded manually (Three Continent AMD Consortium Severity Scale). Visual acuity (VA) was assessed via Early Treatment Diabetic Retinopathy Study (ETDRS) charts. After a 30-second bleaching of the macular region via direct ophthalmoscope, PRT was measured as the seconds to regain VA. Results: First, we analyzed 1208 AugUR participants cross-sectionally (288 with early AMD, and 78 with late AMD). Prolonged PRT was associated with early and late AMD versus no AMD (median PRT = 119.5, 198.0 versus 80.0 seconds, respectively; logistic regression odds ratio [OR] = 1.109–1.165 per 10 seconds, P values < 0.0001). Sensitivity analyses using alternative models or restricting to participants after cataract surgery revealed similar ORs. Second, the association was confirmed in an independent cross-sectional AugUR sample (n = 486). Third, in longitudinal analysis of 233 AugUR participants without AMD, prolonged PRT was associated with incident AMD ascertained 3 years later (follow-up time = 3.2 ± 0.2 years, OR = 1.112–1.162 per 10 seconds, P < 0.05). Overall, we demonstrate a significant association of prolonged PRT with AMD cross-sectionally and longitudinally in elderly individuals. Conclusions: Prolonged PRT might capture retinal function impairment after cell damage before early AMD is visible via color fundus imaging. Translational Relevance: Our results suggest PRT as quantitative predictive biomarker for incident AMD, making it potentially worthwhile also for clinical care

Features of age-related macular degeneration in the general adults and their dependency on age, sex, and smoking : Results from the German KORA study

Acknowledgments We thank all study participants for contributing to the KORA study.Peer reviewedPublisher PD

Genetic Risk Score Analysis Supports a Joint View of Two Classification Systems for Age-Related Macular Degeneration

Purpose: The purpose of this study was to evaluate the utility of combining the Clinical Classification (CC) and the Three Continent age-related macular degeneration (AMD) Consortium Severity Scale (3CACSS) for classification of AMD. Methods: In two independent cross-sectional datasets of our population-based AugUR study (Altersbezogene Untersuchungen zur Gesundheit der Universität Regensburg), we graded AMD via color fundus images applying two established classification systems (CC and 3CACSS). We calculated the genetic risk score (GRS) across 50 previously identified variants for late AMD, its association via logistic regression, and area under the curve (AUC) for each AMD stage. Results: We analyzed 2188 persons aged 70 to 95 years. When comparing the two classification systems, we found a distinct pattern: CC “age-related changes” and CC “early AMD” distinguished individuals with 3CACSS “no AMD”; 3CACSS “mild/moderate/severe early AMD” stages, and distinguished CC “intermediate AMD”. This suggested a 7-step scale combining the 2 systems: (i) “no AMD”, (ii) “age-related changes”, (iii) “very early AMD”, (i.e. CC “early”), (iv) “mild early AMD”, (v) “moderate early AMD”, (vi) “severe early AMD”, and (vii) “late AMD”. GRS association and diagnostic accuracy increased stepwise by increased AMD severity in the 7-step scale and by increased restriction of controls (e.g. for CC “no AMD without age-related changes”: AUC = 55.1%, 95% confidence interval [CI] = 51.6, 58.6, AUC = 62.3%, 95% CI = 59.1, 65.6, AUC = 63.8%, 95% CI = 59.3, 68.3, AUC = 78.1%, 95% CI = 73.6, 82.5, AUC = 82.2%, 95% CI = 78.4, 86.0, and AUC = 79.2%, 95% CI = 75.4, 83.0). A stepwise increase was also observed by increased drusen size and area. Conclusions: The utility of a 7-step scale is supported by our clinical and GRS data. This harmonization and full data integration provides an immediate simplification over using either CC or 3CACSS and helps to sharpen the control group

The development of the würde + infinitive construction in Early Modern German (1650–1800)

This paper presents a corpus-based analysis of the evolution of the würde + infinitive construction in German during the Early Modern period (1650– 1800), using newly available data from the GerManC-corpus. We demonstrate how this construction occupies a unique position orthogonal to both the tense and mood systems of German through an analysis of the syntax and semantics of würde + infinitive clauses, beginning with Modern Standard German and then subsequently with a historical focus on the late seventeenth and eighteenth centuries. Through both quantitative and qualitative analyses, we examine the contexts in which the construction occurs and see how, as it came to be used more frequently over the period in question, it encroached more and more into contexts which had been the preserve of the synthetic preterite subjunctive, even being used in some where the latter is still the norm in modern German. Thus, by the end of the eighteenth century it had become difficult to identify a clear difference in meaning and use between these forms, and the reasons why the würde + in- finitive construction may be preferred over the synthetic preterite subjunctive are by no means clear. We conclude our discussion with an overview of how the würde + infinitive construction was received in the prescriptive tradition during this key period in the standardization of German, seeing its stigmatization in some contexts in part as an attempt by prescriptive grammarians to establish an explicit and clearly justified role for it in the language