Heating analysis for the Pioneer Venus multiprobe mission

The fully coupled, radiating flow field around the entry probes is determined from a detailed calculation which includes equilibrium chemistry, nongray radiative transport, ablation product injection, and a laminar or turbulent boundary layer. Results show that the radiative flux toward the body is attenuated in the boundary layer at downstream regions of the body as well as at the stagnation point and that, even when radiation absorption by ablation products is accounted for, the radiative heating rates along the downstream regions of the body can, under certain conditions, exceed the stagnation point values. It is also shown that, for Venusian entry, the spectral distribution of radiative flux and the magnitude of radiation absorption by ablation products depend strongly on entry velocity, and that the state of the boundary layer can significantly influence the amount of ablation product absorption or emission that occurs in various spectral regions

Identifying the Host Galaxy of Gravitational Wave Signals

One of the goals of the current LIGO-GEO-Virgo science run is to identify transient gravitational wave (GW) signals in near real time to allow follow-up electromagnetic (EM) observations. An EM counterpart could increase the confidence of the GW detection and provide insight into the nature of the source. Current GW-EM campaigns target potential host galaxies based on overlap with the GW sky error box. We propose a new statistic to identify the most likely host galaxy, ranking galaxies based on their position, distance, and luminosity. We test our statistic with Monte Carlo simulations of GWs produced by coalescing binaries of neutron stars (NS) and black holes (BH), one of the most promising sources for ground-based GW detectors. Considering signals accessible to current detectors, we find that when imaging a single galaxy, our statistic correctly identifies the true host ~20% to ~50% of the time, depending on the masses of the binary components. With five narrow-field images the probability of imaging the true host increases to ~50% to ~80%. When collectively imaging groups of galaxies using large field-of-view telescopes, the probability improves to ~30% to ~60% for a single image and to ~70% to ~90% for five images. For the advanced generation of detectors (c. 2015+), and considering binaries within 100 Mpc (the reach of the galaxy catalogue used), the probability is ~40% for one narrow-field image, ~75% for five narrow-field images, ~65% for one wide-field image, and ~95% for five wide-field images, irrespective of binary type.Comment: 5 pages, 2 figure

An experimental study of the oxidation of graphite in high-temperature supersonic and hypersonic environments

Graphite oxidation in high temperature supersonic and hypersonic streams of air and air-nitrogen mixture

Experimental L-band SST satellite communications/surveillance terminal study. Volume 1 - Study summary

Study of design for experimental L band supersonic transport communications/surveillance termina

The Rocketdyne Multifunction Tester. Part 1: Test Method

The Rocketdyne Multifunction Tester is a general purpose test apparatus which utilizes axial and radial magnetic bearings as shaft excitation devices. The tester is modular in design so that different seal and bearing packages can be tested on the same test stand. The tester will be used for rotordynamic coefficient extraction, as well as life and fluid/material compatibility evaluations. Use of a magnetic bearing as a shaft excitation device opens up many possibilities for shaft excitation and rotordynamic coefficient extraction. In addition to describing the basic apparatus, some of the excitation and extraction methods are described. Some of the excitation methods to be discussed include random, aperiodic, harmonic, impulse and chirp

Not just for Christmas

This is the working paper for the project ‘Not Just for Christmas: consumption, popular culture and religious observance’. This workshop engages academic and non-academic participants in the discussion of issues surrounding ethical responses to visual culture, consumption, and their embedding in moral and religious narratives at Christmas. The interdisciplinary workshop will, through a series of events, bring diverse scholars together to critically explore the ethical dilemmas faced in contemporary cultural experience of Christmas and open a positive dialogue over how such choices are informed by popular culture and also expressed through religious symbolism and ritual. The overlapping layers of this debate, intensified during the festive season of Christmas, will be related to sustainability and ethical consumption in daily life. The project recognises the following intersections of consumption, popular culture and religious observance: - Broadcasting, advertising and marketing employ the reflexive ethical awareness of consumers, often expressed through resistance - Ethical approaches to Christmas are often led by religious or charitable organisations, yet also embrace wider issues relating to all consumption - Embedded or nested narratives of Christmas in visual culture are often appreciated independently from their religious origins, yet are nonetheless historically reliant upon them - Ethical or spiritual concerns of consumers are translated into, or appropriated from, Christmas traditions, rituals, objects, spaces and narratives The complex issues raised by these intersections are illustrated in media approaches to Christmas, in the religious symbolism and liturgical practices of Advent and Christmas, as well as by consumer practices and in the spaces of consumption. The workshop will, using a mixture of academic and non-academic participants, object-led and online discussion, discursive publication and public feedback, reveal flashlight issues which will offer new areas of research and inquiry, as well as provide a necessary reappraisal of Christmas in light of changing societal impulses and needs. The workshop events respond to and address complex debates which may transcend religious belief but which often rely upon shared conceptions. Such debates cover the commercialisation of Christmas and other religious festivals in the context of ethical consumption practices including Fair Trade, charity donations, gift-giving alternatives and greeting cards. The intellectual contribution of the project will be an informed ‘user guide’ to ethical consumption and the moral and spiritual issues it raises every day, guided by serious and sustained critical debate around Christmas. This guidance will be disseminated through the archived online forum and symposium, as well as the project’s webpage. Central to this is a ‘working paper’, written in plain language for a wide audience, which will report on the critical discussion of ethical consumption, Christian narratives, and visual/popular culture. The paper frames the guidance that these discussions have for viewers, consumers and religious practitioners in making ethical choices in daily life, and not just for Christmas

The Dreaming Variational Autoencoder for Reinforcement Learning Environments

Reinforcement learning has shown great potential in generalizing over raw sensory data using only a single neural network for value optimization. There are several challenges in the current state-of-the-art reinforcement learning algorithms that prevent them from converging towards the global optima. It is likely that the solution to these problems lies in short- and long-term planning, exploration and memory management for reinforcement learning algorithms. Games are often used to benchmark reinforcement learning algorithms as they provide a flexible, reproducible, and easy to control environment. Regardless, few games feature a state-space where results in exploration, memory, and planning are easily perceived. This paper presents The Dreaming Variational Autoencoder (DVAE), a neural network based generative modeling architecture for exploration in environments with sparse feedback. We further present Deep Maze, a novel and flexible maze engine that challenges DVAE in partial and fully-observable state-spaces, long-horizon tasks, and deterministic and stochastic problems. We show initial findings and encourage further work in reinforcement learning driven by generative exploration.Comment: Best Student Paper Award, Proceedings of the 38th SGAI International Conference on Artificial Intelligence, Cambridge, UK, 2018, Artificial Intelligence XXXV, 201

RECYCLED SUBSTRATES: PLANT BIOMASS AND PLANT COVER CORRELATION

Green roofs extend roof membrane life and reduce waste to landfills. However, green roof costs must be reduced if their benefits are to accrue more widely. Use of recycled materials may reduce costs and also keep those materials out of landfills. Some work has been done on use of local recycled materials for green roof substrates, but none describe the characteristics, proportions and results of using an entire suite of blended recycled materials in admixtures (i.e., mixtures of very different materials) such as crumb rubber (CR), crushed used brick (CB) and compost (CPT) in concert with greens grade sand (#10), biochar (B) and topsoil inoculum (T). How does plant growth and performance on recycled substrates compare with a typical expanded shale and clay (ESC) substrate? Two main techniques for measuring performance of green roof treatments are plant biomass and plant coverage. Both measure plant growth and performance, while coverage specifically addresses FLL (Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau Guidelines for the Planning, Construction and Maintenance of Green Roofing) standards. This research project tested native plants on recycled substrate admixtures to assess the correlation between these two measures. It was found that the biomass and cover were strongly correlated at 0.665 (P \u3c.0001). Recycled substrate admixtures were found to be heavier, hold less water and had significantly less biomass and cover than the proprietary green roof substrate used as a control, but their native plantings still held the substrate in place. It is suggested that compost is a key ingredient for biomass production and future recycled green roof substrate might use recycled crumb rubber, biochar and compost for lighter substrate loading

A MODEL OF HUMAN SCALE TESTED ON RURAL LANDSCAPE SCENES

Landscapes such as the Great Plains have been described as lacking human scale. This study developed a quantitative model of human scale and compared it with viewers\u27 perceptions of visual structure. Visual structure was selected from the physical features of Otoe County, NE, forming boundaries, found as ground textures, vegetative screens, and topographic breaks and was depicted in photographs of landscape scenes. The model used and tested nine classes of scale based on grain and extent of the photos rated by viewers against those from the model. Viewers identified boundaries representing grain and extent that were synthesized into a viewer-perceived scale class. Good agreement with the proposed model occurred at four smaller scales but deteriorated as scale increased. Larger-scale scenes appear to offer more opportunities for the viewer to select closer or farther visual boundaries, thus changing their interpretation of scale