Technology requirements for advanced earth-orbital transportation systems, dual-mode propulsion

The application of dual-mode propulsion concepts to fully reusable single-stage-to-orbit (SSTO) vehicles is discussed. Dual-mode propulsion uses main rocket engines that consume hydrocarbon fuels as well as liquid hydrogen fuel. Liquid oxygen is used as the oxidizer. These engine concepts were integrated into transportation vehicle designs capable of vertical takeoff, delivering a payload to earth orbit, and return to earth with a horizontal landing. Benefits of these vehicles were assessed and compared with vehicles using single-mode propulsion (liquid hydrogen and oxygen engines). Technology requirements for such advanced transportation systems were identified. Figures of merit, including life-cycle cost savings and research costs, were derived for dual-mode technology programs, and were used for assessments of potential benefits of proposed technology activities. Dual-mode propulsion concepts display potential for significant cost and performance benefits when applied to SSTO vehicles

Technology requirements for advanced earth-orbital transportation systems: Summary report

Areas of advanced technology that are either critical or offer significant benefits to the development of future Earth-orbit transportation systems were identified. Technology assessment was based on the application of these technologies to fully reusable, single-state-to-orbit (SSTO) vehicle concepts with horizontal landing capability. Study guidelines included mission requirements similar to space shuttle, an operational capability beginning in 1995, and main propulsion to be advanced hydrogen-fueled rocket engines. The technical and economic feasibility of this class of SSTO concepts were evaluated as well as the comparative features of three operational take-off modes, which were vertical boost, horizontal sled launch, and horizontal take-off with subsequent inflight fueling. Projections of both normal and accelerated technology growth were made. Figures of merit were derived to provide relative rankings of technology areas. The influence of selected accelerated areas on vehicle design and program costs was analyzed by developing near-optimum point designs

Multi-Attribute SCADA-Specific Intrusion Detection System for Power Networks

The increased interconnectivity and complexity of supervisory control and data acquisition (SCADA) systems in power system networks has exposed the systems to a multitude of potential vulnerabilities. In this paper, we present a novel approach for a next-generation SCADA-specific intrusion detection system (IDS). The proposed system analyzes multiple attributes in order to provide a comprehensive solution that is able to mitigate varied cyber-attack threats. The multiattribute IDS comprises a heterogeneous white list and behavior-based concept in order to make SCADA cybersystems more secure. This paper also proposes a multilayer cyber-security framework based on IDS for protecting SCADA cybersecurity in smart grids without compromising the availability of normal data. In addition, this paper presents a SCADA-specific cybersecurity testbed to investigate simulated attacks, which has been used in this paper to validate the proposed approach

Conviviality and Parallax in David Olusoga’s Black and British: A Forgotten History

Through examining the BBC television series, Black and British: A Forgotten History, written and presented by the historian David Olusoga, and in extending Paul Gilroy’s assertion that the everyday, banality of living with difference is now an ordinary part of British life, this article considers how Olusoga’s historicization of the black British experience reflects a convivial rendering of UK multiculture. In particular, when used alongside Žižek’s notion of parallax, it is argued that understandings of convivial culture can be supported by a historical importance that deliberately ‘shocks’ and, subsequently dislodges, popular interpretations of the UK’s ‘white past’. Notably, it is parallax which puts antagonism, strangeness and ambivalence at the heart of contemporary depictions of convivial Britain, with the UK’s cultural differences located in the ‘gaps’ and tensions which characterize both its past and present. These differences should not be feared but, as a characteristic part of our convivial culture, should be supplemented with historical analyses that highlight but, also, undermine, the significance of cultural differences in the present. Consequently, it is suggested that if the spontaneity of conviviality is to encourage openness, then, understandings of multiculturalism need to go beyond reification in order to challenge our understandings of the past. Here, examples of ‘alterity’ are neither ‘new’ nor ‘contemporary’ but, instead, constitute a fundamental part of the nation’s history: of the ‘gap’ made visible in transiting past and present

The celebrity entrepreneur on television: profile, politics and power

This article examines the rise of the ‘celebrity entrepreneur’ on television through the emergence of the ‘business entertainment format’ and considers the ways in which regular television exposure can be converted into political influence. Within television studies there has been a preoccupation in recent years with how lifestyle and reality formats work to transform ‘ordinary’ people into celebrities. As a result, the contribution of vocationally skilled business professionals to factual entertainment programming has gone almost unnoticed. This article draws on interviews with key media industry professionals and begins by looking at the construction of entrepreneurs as different types of television personalities and how discourses of work, skill and knowledge function in business shows. It then outlines how entrepreneurs can utilize their newly acquired televisual skills to cultivate a wider media profile and secure various forms of political access and influence. Integral to this is the centrality of public relations and media management agencies in shaping media discourses and developing the individual as a ‘brand identity’ that can be used to endorse a range of products or ideas. This has led to policy makers and politicians attempting to mobilize the media profile of celebrity entrepreneurs to reach out and connect with the public on business and enterprise-related issues

Deep-water macroalgae from the Canary Islands: new records and biogeographical relationships

Due to the geographical location and paleobiogeography of the Canary Islands, the seaweed flora contains macroalgae with different distributional patterns. In this contribution, the biogeographical relations of several new records of deep-water macroalgae recently collected around the Canarian archipelago are discussed. These are Bryopsidella neglecta (Berthotd) Rietema,Discosporangium mesarthrocarpum (Meneghini) Hauck, Hincksia onslowensis (Amsler et Kapraun)P.C. Silva, Syringoderma floridana Henry, Peyssonnelia harveyana J. Agardh, Cryptonemia seminervis(C. Agardh) J. Agardh, Botryodadia wynnei Ballantine, Gloiocladia blomquistii (Searles) R. E.Norris, PIahchrysis peltata (W. R. Taylor) P. Huv4 et H. Huv4, Leptofauchea brasiliensis Joly, and Sarcodiotheca divaricata W. R. Taylor. These new records, especially those in the Florideophyceae,support the strong affinity of the Canary Islands seaweed flora with the warm-temperate Mediterranean-Atlantic region. Some species are recorded for the first time from the east coast of the Atlantic Ocean, enhancing the biogeographic relations of the Canarian marine flora with that of the western Atlantic regions

South Georgia palaeo-productivity and glacial evolution over the past 15 ka

This is the author accepted manuscript. The final version is available from the Grzybowski FoundationLeverhulme Trus

The difference that tenure makes

This paper argues that housing tenures cannot be reduced to either production relations or consumption relations. Instead, they need to be understood as modes of housing distribution, and as having complex and dynamic relations with social classes. Building on a critique of both the productionist and the consumptionist literature, as well as of formalist accounts of the relations between tenure and class, the paper attempts to lay the foundations for a new theory of housing tenure. In order to do this, a new theory of class is articulated, which is then used to throw new light on the nature of class-tenure relations

Cumberland Bay (South Georgia) glacial evolution during the Holocene

This is the final version. Available via the link in this recordToday, South Georgia is heavily glaciated with glaciers often terminating into the ocean via steep-sided bay and U-shaped valleys. However, due to a low number of well-dated climate records from the island, there is uncertainty about how glaciers responded to Holocene climate variability. Here, we reconstruct the glacial evolution of Cumberland Bay, one of the most dynamic glacial systems in the world, from marine sediment core GC673 (ca. 9.7 cal. Kyr BP to Present; ca. 6 m from the nearest land). We used benthic foraminiferal and diatom assemblages, biogenic silica, alkenones and pXRF to infer Holocene glacial evolution in Cumberland Bay. The relative abundance of the benthic foraminifera Fursenkoina fusiformis is interpreted as a proxy for more intense diatom blooms resulting from increased terrestrial runoff associated with the spring-summer melting of glaciers. The F. fusiformis abundance correlates well with diatom concentration accumulation rates and peaks in both proxies correspond to elevated (but low) abundance of sea ice diatom taxa. A sequence of several glacial advancement events can be recognized. The high productivity of the early Holocene is associated with melt associated with the retreat of glaciers into the inner fjord during the early Holocene warm period. Subsequent advancements seem to have two different causes. The first mid-Holocene advancement corresponds to a decrease in alkenone-derived palaeotemperatures from GC673. The two advancements from the late Holocene correspond to increases in published LOI data suggested as indicating increased strength of the South Westerly Winds (SWW) at the latitude of South Georgia which would have increased winter snowfall aiding the growth of glaciers. Our proxies are aligned with and build upon published glacial trends previously constrained with plant macrofossil and pollen evidence from nearby peat bogs and dated glacial moraines. We conclude that the primary driver of productivity at site GC673 were diatom blooms associated with spring/summer melt of glaciers whose growth is partially associated with strengthened SSW