An improved atatistical method for measuring reliability with special reference to rocket engines

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PTFE as a viable sealing material for lightweight mass spectrometry ovens in dusty extraterrestrial environments

Ever increasing interest in the Moon, not only for scientific but also commercial and prospecting purposes, requires a more streamlined and reproduceable approach to issues such as the sealing of sample handling ovens, in contrast to the mission-specific mechanisms which have tended to prevail in the past. A test breadboard has been designed and built in order to evaluate the leak rates of different oven sealing concepts and materials within the context of the ProSPA instrument being developed for the European Space Agency. Sealing surface geometries based on a simple 90° knife-edge, and two widely used vacuum fitting standards (VCR® and ConFlat®) have been tested using PTFE gaskets in vacuum across a temperature range of -100°C to 320°C, equivalent to a projected -100°C to 1000°C sample heating range in the ProSPA ovens. The impact of using glass- and carbon- filled PTFE has also been investigated, as has the effect of dust coverage of JSC-1A lunar simulant up to 9 per cent by area. The best combination of properties appears to be unfilled PTFE, compressed between two 90° knife-edges with a confining force of ∼ 400 N. This can produce a leak rates within the 10−7 Pa.m3.s−1 range or better regardless of the level of dust applied within the experimental constraints. A strong temperature-dependence on the leak rate is identified, meaning that careful oven design will be required to minimise the temperature at the seal interface even within the operational temperature range PTFE itself

Examining the Links between Multi-Frequency Multibeam Backscatter Data and Sediment Grain Size

Publication history: Accepted - 13 April 2021Acoustic methods are routinely used to provide broad scale information on the geographical distribution of benthic marine habitats and sedimentary environments. Although single-frequency multibeam echosounder surveys have dominated seabed characterisation for decades, multifrequency approaches are now gaining favour in order to capture different frequency responses from the same seabed type. The aim of this study is to develop a robust modelling framework for testing the potential application and value of multifrequency (30, 95, and 300 kHz) multibeam backscatter responses to characterize sediments’ grain size in an area with strong geomorphological gradients and benthic ecological variability. We fit a generalized linear model on a multibeam backscatter and its derivatives to examine the explanatory power of single-frequency and multifrequency models with respect to the mean sediment grain size obtained from the grab samples. A strong and statistically significant (p < 0.05) correlation between the mean backscatter and the absolute values of the mean sediment grain size for the data was noted. The root mean squared error (RMSE) values identified the 30 kHz model as the best performing model responsible for explaining the most variation (84.3%) of the mean grain size at a statistically significant output (p < 0.05) with an adjusted r2 = 0.82. Overall, the single low-frequency sources showed a marginal gain on the multifrequency model, with the 30 kHz model driving the significance of this multifrequency model, and the inclusion of the higher frequencies diminished the level of agreement. We recommend further detailed and sufficient ground-truth data to better predict sediment properties and to discriminate benthic habitats to enhance the reliability of multifrequency backscatter data for the monitoring and management of marine protected areas.This research was funded by the Marine Institute under the Marine Research Programme by the Irish Government Cruise CE19007 Backscatter and Biodiversity of Shelf Sea Habitats (BaBioSSH) survey. Staffing was supported through the Marine Protected Area Monitoring and Management (MarPAMM) project, which is supported by the European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPM) with matching funding from the Government of Ireland, the Northern Ireland Executive, and the Scottish Government, as well as the PhD studentship through a Vice Chancellor Research Scholarship of Ulster University (U.K.)

The Ursinus Weekly, May 1, 1975

S.F.A.R.C. update • Meistersingers: More than music • USGA questionnaire encourages response • New Yorker critic graduation speaker • Medical school entrances • How to succeed debuts tomorrow in Bearpit • Editorial: Disgust: By the students, of the students! • Letters to the editor: Meekness? • Alumni meet • Feminism: Where? • Inexpensive or just plain cheap • Actors comment • Conflict simulation activities • 2 games, 2 losses • Tennis time • Intramurals • Focus: Steve Fisher • Flyers go for cup! • Lacrosse lookout • Requesthttps://digitalcommons.ursinus.edu/weekly/1037/thumbnail.jp

Effect of nivolumab (NIVO) on quality of life (QoL) in patients (pts) with treatment-naïve advanced melanoma (MEL): results of a phase III study (CheckMate 066)

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Towards a Sustainable, Participatory and Inclusive Wild Meat Sector

First paragraph: Expanding human demands on land, sea and fresh water have led to our planet experiencing unprecedented levels of wildlife declines and extirpations (Ceballos et al., 2017). The Living Planet Index (LPI) as an indicator of global vertebrate abundance declined by up to 58% between 1970–2012 (WWF, 2016). In the most recent version of the International Union for Conservation of Nature’s (IUCN) Red List as many as 32% of assessed vertebrate species are decreasing in terms of both population size and range (IUCN 2017). Larger species are suffering the steepest and most irreversible declines (Dirzo et al., 2014; Ripple et al., 2014, 2015). As wildlife is lost, biodiversity is reduced and ecosystem integrity suffers (Dirzo et al., 2014; Young et al., 2016)

Microstructural evolution and transmutation in tungsten under ion and neutron irradiation

This study aims to compare the effects of neutron and self-ion irradiation on the mechanical properties and microstructural evolution in W. Neutron irradiation at the HFR reactor to 1.67 dpa at 800 °C resulted in the formation of large Re and Os rich clusters and voids. The post-irradiation composition was measured using APT and verfified against FISPACT modelling. The measured Re and Os concentration was used to create alloys with equivalent concentrations of Re and Os. These alloys were exposed to self-ion irradiation to a peak dose of 1.7 dpa at 800 °C. APT showed that self-ion irradiation leads to the formation of small Os clusters, wheras under neutron irradiation large Re/Os clusters form. Voids are formed by both ion and neutron irradiation, but the voids formed by neutron irradiation are larger. By comparing the behaviour of W-1.4Re and W-1.4Re-0.1Os, suppression of Re cluster formation was observed. Irradiation hardening was measured using nanoindentation and was found to be 2.7 GPa, after neutron irradiation and 1.6 GPa and 0.6 GPa for the self-ion irradiated W-1.4Re and W-1.4Re-0.1Os. The higher hardening is attributed to the barrier strength of large voids and Re/Os clusters that are observed after neutron irradiation

The Lantern Vol. 37, No. 1, Fall 1970

• Circumstance • Advice • For What You Do For Me • Blink • Love • Love II • Magic • To Be a Child • A Year Later • A Poem in February • The Crystal Brick Road • Ephemera • Life • Whiskers • Thoughts On Being Sick • A Non-Poem • A Gruk Anthology • Moon • A Thought • Dwarf in an Existential Dawn • Corridors To My Mind • Sadness • The Enzyme Song • Creatures of Sandhttps://digitalcommons.ursinus.edu/lantern/1098/thumbnail.jp