Development of an innovative validation strategy of gas–surface interaction modelling for re‑entry applications

Abstract This paper summarises the final synthesis of an ESA technology research programme entitled “Development of an Innovative Validation Strategy of Gas Surface Interaction Modelling for Re-entry Applications”. The focus of the project was to demonstrate the correct pressure dependency of catalytic surface recombination, with an emphasis on Low Earth Orbit (LEO) re-entry conditions and thermal protection system materials. A physics-based model describing the prevalent recombination mechanisms was proposed for implementation into two CFD codes, TINA and TAU. A dedicated experimental campaign was performed to calibrate and validate the CFD model on TPS materials pertinent to the EXPERT space vehicle at a wide range of temperatures and pressures relevant to LEO. A new set of catalytic recombination data was produced that was able to improve the chosen model calibration for CVD-SiC and provide the first model calibration for the Nickel–Chromium super-alloy PM1000. The experimentally observed pressure dependency of catalytic recombination can only be reproduced by the Langmuir–Hinshelwood recombination mechanism. Due to decreasing degrees of (enthalpy and hence) dissociation with facility stagnation pressure, it was not possible to obtain catalytic recombination coefficients from the measurements at high experimental stagnation pressures. Therefore, the CFD model calibration has been improved by this activity based on the low pressure results. The results of the model calibration were applied to the existing EXPERT mission profile to examine the impact of the experimentally calibrated model at flight relevant conditions. The heat flux overshoot at the CVDSiC/PM1000 junction on EXPERT is confirmed to produce radiative equilibrium temperatures in close proximity to the PM1000 melt temperature.This was anticipated within the margins of the vehicle design; however, due to the measurements made here for the first time at relevant temperatures for the junction, an increased confidence in this finding is placed on the computations

Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization

Time-resolved magneto-optical Kerr effect (MOKE) and Brillouin light scattering (BLS) spectroscopy are important techniques for the investigation of magnetization dynamics. Within this article, we calculate analytically the MOKE and BLS signals from prototypical spin-wave modes in the ferromagnetic layer. The reliability of the analytical expressions is confirmed by optically exact numerical calculations. Finally, we discuss the dependence of the MOKE and BLS signals on the ferromagnetic layer thickness

Innovative Thermal Management Concepts and Material Solutions for Future Space Vehicles

When entering a planetary atmosphere, space vehicles are exposed to extreme thermal loads. To protect the vehicle’s interior, a thermal protection system is required. Future aerospace transportation demands solutions that exceed the performance of current systems and up-to-date material limits. Therefore, new and disruptive solutions must be envisaged to meet those extreme conditions. In the search of new solutions for sharp leading edges of future hypersonic reentry or transport vehicles, the THOR project, composed of eight European organizations (industries, research centers, and universities) and one Japanese Agency (Japan Aerospace Exploration Agency), is actively working on definition, design, implementation, and simulation of new passive and active thermal management solutions and their verification in relevant environments (high-enthalpy facilities). This paper provides an overview of the recent developments on the four concepts that are targeted in the project, applying different physical methodologies: 1) passive cooling using highly conductive carbon-based fibers, 2) passive cooling with intensive internal radiative exchange, 3) active cooling based on convection heat transfer using a ceramic sandwich/thermal protection system with ceramic foams/lattices, and 4) active transpiration cooling of external surfaces. Details on these thermal management concepts, requirements from end users, and test configurations, as well as results from experimental and numerical verification, are given

Operating Cabled Underwater Observatories in Rough Shelf-Sea Environments:A Technological Challenge

Cabled coastal observatories are often seen as future-oriented marine technology that enables science to conduct observational and experimental studies under water year-round, independent of physical accessibility to the target area. Additionally, the availability of (unrestricted) electricity and an Internet connection under water allows the operation of complex experimental setups and sensor systems for longer periods of time, thus creating a kind of laboratory beneath the water. After successful operation for several decades in the terrestrial and atmospheric research field, remote controlled observatory technology finally also enables marine scientists to take advantage of the rapidly developing communication technology. The continuous operation of two cabled observatories in the southern North Sea and off the Svalbard coast since 2012 shows that even highly complex sensor systems, such as stereo-optical cameras, video plankton recorders or systems for measuring the marine carbonate system, can be successfully operated remotely year-round facilitating continuous scientific access to areas that are difficult to reach, such as the polar seas or the North Sea. Experience also shows, however, that the challenges of operating a cabled coastal observatory go far beyond the provision of electricity and network connection under water. In this manuscript, the essential developmental stages of the "COSYNA Shallow Water Underwater Node" system are presented, and the difficulties and solutions that have arisen in the course of operation since 2012 are addressed with regard to technical, organizational and scientific aspects.</p

6- and 8-Prenylnaringenin, Novel Natural Histone Deacetylase Inhibitors Found in Hops, Exert Antitumor Activity on Melanoma Cells

Background/Aims: Prenylnaringenins are natural prenylflavonoids with anticancer properties. However, the underlying mechanisms have not been elucidated yet. Here we report a novel mode of action of 6- and 8-prenylnaringenin (PN) on human melanoma cells: Inhibition of cellular histone deacetylases (HDACs). Methods: We performed in silico and in vitro analyses using 6-PN or 8-PN to study a possible interaction of 6-PN or 8-PN with HDAC as well as Western blot and FACS analyses, real-time cell proliferation and cell viability assays to assess the impact of 6-PN and 8-PN on human metastatic melanoma cells. Results: In silico, 6-PN and 8-PN fit into the binding pocket of HDAC2, 4, 7 and 8, binding to the zinc ion of their catalytic center that is essential for enzymatic activity. In vitro, 100 µmol/L of 6-PN or 8-PN inhibited all 11 conserved human HDAC of class I, II and IV. In clinical oncology HDAC inhibitors are currently investigated as new anticancer compounds. In line, treatment of SK-MEL-28 cells with 6-PN or 8-PN induced a hyperacetylation of histone complex H3 within 2 h. Further, 6-PN or 8-PN mediated a prominent, dose-dependent reduction of cellular proliferation and viability of SK-MEL-28 and BLM melanoma cells. This effect was apoptosis-independent and accompanied by down-regulation of mTOR-specific pS6 protein via pERK/pP90 in SK-MEL-28 cells. Conclusion: The identification of a broad inhibitory capacity of 6-PN and 8-PN for HDAC enzymes with antiproliferative effects on melanoma cells opens the perspective for clinical application as novel anti-melanoma drugs and the usage as innovative lead structures for chemical modification to enhance pharmacology or inhibitory activities

Die politische Aufgabe von Religion

Das Verhältnis von Religion und Politik ist in den vergangenen Jahren verstärkt in den Fokus der Forschung gerückt. Die Autoren dieses Bandes widmen sich diesem Verhältnis unter einer besonderen Zuspitzung. Ihre Beiträge analysieren, inwiefern es zum Selbstverständnis von Religionen gehört, einen Beitrag zur Gestaltung der gesellschaftlichen und politischen Wirklichkeit leisten zu sollen. Mit dieser Problematik verknüpft ist eine zentrale Frage: Wie erklärt und wie äußert sich der Anspruch von Religionen, eine »politische Aufgabe« zu besitzen? Im Fokus stehen die drei großen monotheistischen Religionen Judentum, Christentum und Islam, wobei für das Christentum zusätzlich die konfessionellen Differenzen in den Blick kommen, die zu ganz unterschiedlichen Einschätzungen der politischen Aufgabe des Christentums geführt haben.Für alle drei monotheistischen Religionen nehmen die Beiträger jeweils eine Doppelperspektive ein: historische Beispiele erhellen die jeweiligen Bedingungen und Kontexte für religiös motivierte Teilhabe an politischer Gestaltung und Verantwortung; Systematische Entfaltungen versuchen eine Einbettung dieser Beispiele in die spezifischen Denkhorizonte der jeweiligen Religionen. Das so erhobene politische Selbstverständnis der Religionen wird schließlich mit der Fremdwahrnehmung dieses Selbstverständnisses aus nichtreligiöser Perspektive kontrastiert

Die politische Aufgabe von Religion

Das Verhältnis von Religion und Politik ist in den vergangenen Jahren verstärkt in den Fokus der Forschung gerückt. Die Autoren dieses Bandes widmen sich diesem Verhältnis unter einer besonderen Zuspitzung. Ihre Beiträge analysieren, inwiefern es zum Selbstverständnis von Religionen gehört, einen Beitrag zur Gestaltung der gesellschaftlichen und politischen Wirklichkeit leisten zu sollen. Mit dieser Problematik verknüpft ist eine zentrale Frage: Wie erklärt und wie äußert sich der Anspruch von Religionen, eine »politische Aufgabe« zu besitzen? Im Fokus stehen die drei großen monotheistischen Religionen Judentum, Christentum und Islam, wobei für das Christentum zusätzlich die konfessionellen Differenzen in den Blick kommen, die zu ganz unterschiedlichen Einschätzungen der politischen Aufgabe des Christentums geführt haben.Für alle drei monotheistischen Religionen nehmen die Beiträger jeweils eine Doppelperspektive ein: historische Beispiele erhellen die jeweiligen Bedingungen und Kontexte für religiös motivierte Teilhabe an politischer Gestaltung und Verantwortung; Systematische Entfaltungen versuchen eine Einbettung dieser Beispiele in die spezifischen Denkhorizonte der jeweiligen Religionen. Das so erhobene politische Selbstverständnis der Religionen wird schließlich mit der Fremdwahrnehmung dieses Selbstverständnisses aus nichtreligiöser Perspektive kontrastiert

May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension

Aims Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries. Methods and results Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. Conclusion May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk