Uniform engine testing program. Phase 1: NASA Lewis Research Center participation

Two jet engines were tested under identical conditions in a variety of altitude and ground level facilities as a means to correlating these facilities. Two J57-19W turbojet engines were tested in an altitude test facility. The test results are summarized

Delivering authentic online practical science teaching – geoscience perspectives from the OpenScience Laboratory

Teaching practical science at a distance is challenging – how do you give students studying online a meaningful practical experience? In July 2013, the Open University (OU) launched the Wolfson OpenScience Laboratory (OSL) to deliver a wide a range of authentic practical science activities for their distance learning undergraduates. Prompted by the recognition that modern science is increasingly conducted via a computer screen (e.g. remote sensing, Martian fieldwork), the OSL presents a variety of opportunities for students to observe, investigate, gather and analyse data. The rationale is to foster problem-based, active learning, which has been proven effective by numerous studies. Simulation is kept to a minimum; most activities either generate or use real data, with authentic anomalies and ‘noise’ included – an aspect valued by the students. Geoscience is rooted in raw data collected during practical investigations, notably fieldwork. A key skill is observation, so the OSL includes digital collections of minerals, rocks and fossils, as zoomable, high resolution images and 360° videos for the 3D perspective. The Virtual Microscope enables petrographic examination of thin sections using high-quality zoomable images, in both plane- and cross polarised light, with rotation of the sample for certain points of interest. There is a virtual field trip based in a multi-user virtual environment (MUVE), as well as an exercise on maps and landforms. Developed primarily for OU undergraduates, many of the assets in the OSL are being made more openly accessible, with free registration. We are developing partnerships with other universities and schools, both as users and contributors to further assets (e.g. thin section collections). We have also gathered feedback from several surveys of OU undergraduates, as well as external users. Feedback on the pedagogical aspects of the OSL is broadly positive, with some assets (e.g. the virtual microscope) garnering particular praise; respondents value the potential for interaction with experts but also desire an explicit connection to the materials’ original field context. However, technological issues at times present a barrier to learning – perhaps reflecting the high diversity of OU cohorts, especially in terms of their individual hardware, software and IT skills. Some students resent the time investment required to master specialised scientific software, though it could be argued that acquiring such IT skills is an essential part of practising modern science

High-Frequency-Induced Cathodic Breakdown during Plasma Electrolytic Oxidation

The present communication shows the possibility of observing microdischarges under cathodic polarization during plasma electrolytic oxidation at high frequency. Cathodic microdischarges can ignite beyond a threshold frequency found close to 2 kHz. The presence (respectively, absence) of an electrical double layer is put forward to explain how the applied voltage can be screened, which therefore prevents (respectively, promotes) the ignition of a discharge. Interestingly, in the conditions of the present study, the electrical double layer requires between 175 and 260 μs to form. This situates the expected threshold frequency between 1.92 and 2.86 kHz, which is in good agreement with the value obtained experimentally

Summary of investigations of engine response to distorted inlet conditions

A survey is presented of experimental and analytical experience of the NASA Lewis Research Center in engine response to inlet temperature and pressure distortions. This includes a description of the hardware and techniques employed, and a summary of the highlights of experimental investigations and analytical modeling. Distortion devices successfully simulated inlet distortion, and knowledge was gained about compression system response to different types of distortion. A list of NASA research references is included

Moving beyond the circular economy

The production model, which currently underpins our material prosperity, remains highly resource-intensive, and the volume of minerals, ores and fossil fuels consumed annually is set to triple by 2050 unless economic growth is decoupled from resource consumption [1]. One response that has been attracting significant attention is the idea of a circular economy (or close loop economy), in which waste is transformed into value rather than disposed of to landfill [2]. While acknowledging potential benefits to businesses of a circular economy, this paper critically reviews the model and proposes an approach that addresses concerns that even recycling processes have energy impacts through transportation, reprocessing and subsequent manufacturing, and that in practice it is impossible to have a complete circular system in which there is no use of virgin materials and no final waste. It presents an overarching framework that responds to such concerns, built by studying different circular models in a macro-level perspective and then tailoring tactics for different sectors in a micro - level perspective [3 ,4,5,6 ]. The paper explains how the framework was built and how it is applied to the large household appliance (LHA) sector, through developing two emerging models based on product-service systems (PSS). The paper presents findings from a workshop in which the two models were presented to industry representatives, revealing their responses regarding the opportunities and challenges to implement the proposed models to go beyond the circular economy

Gravitational wave emission from a magnetically deformed non-barotropic neutron star

A strong candidate for a source of gravitational waves is a highly magnetised, rapidly rotating neutron star (magnetar) deformed by internal magnetic stresses. We calculate the mass quadrupole moment by perturbing a zeroth-order hydrostatic equilibrium by an axisymmetric magnetic field with a \emph{linked poloidal-toroidal structure}. In this work, we do \emph{not} require the model star to obey a barotropic equation of state (as a realistic neutron star is not barotropic), allowing us to explore the hydromagnetic equilibria with fewer constraints. We derive the relation between the ratio of poloidal-to-total field energy $\Lambda$ and ellipticity $\epsilon$ and briefly compare our results to those obtained using the barotropic assumption. Then, we present some examples of how our results can be applied to astrophysical contexts. First, we show how our formulae, in conjunction with current gravitational wave (non-)detections of the Crab pulsar and the Cassiopeia A central compact object (Cas A CCO), can be used to constrain the strength of the internal toroidal fields of those objects. We find that, for the Crab pulsar (whose canonical equatorial dipole field strength, inferred from spin down, is $4\times 10^8$ T) to emit detectable gravitational radiation, the neutron star must have a strong toroidal field component, with maximum internal toroidal field strength $B_{\mathrm{tm}}=7\times 10^{12}$ T; for gravitational waves to be detected from the Cas A CCO at 300 Hz, $B_{\mathrm{tm}}\sim 10^{13}$ T, whereas detection at 100 Hz would require $B_{\mathrm{tm}}\sim 10^{14}$ T. Using our results, we also show how the gravitational wave signal emitted by a magnetar immediately after its birth (assuming it is born rapidly rotating, with $\Lambda\lesssim 0.2$) makes such a newborn magnetar a stronger candidate for gravitational wave detection than, for example, an SGR giant flare.Comment: 15 pages, 8 figures, 2 table

Fermi surface instabilities in CeRh2Si2 at high magnetic field and pressure

We present thermoelectric power (TEP) studies under pressure and high magnetic field in the antiferromagnet CeRh2Si2 at low temperature. Under magnetic field, large quantum oscillations are observed in the TEP, S(H), in the antiferromagnetic phase. They suddenly disappear when entering in the polarized paramagnetic (PPM) state at Hc pointing out an important reconstruction of the Fermi surface (FS). Under pressure, S/T increases strongly of at low temperature near the critical pressure Pc, where the AF order is suppressed, implying the interplay of a FS change and low energy excitations driven by spin and valence fluctuations. The difference between the TEP signal in the PPM state above Hc and in the paramagnetic state (PM) above Pc can be explained by different FS. Band structure calculations at P = 0 stress that in the AF phase the 4f contribution at the Fermi level (EF) is weak while it is the main contribution in the PM domain. By analogy to previous work on CeRu2Si2, in the PPM phase of CeRh2Si2 the 4f contribution at EF will drop.Comment: 10 pages, 13 figure