A Performance Analysis of Folding Conformal Propeller Blade Designs

NASAs X-57 Maxwell flight demonstrator has a high-lift system that includes 12 fixed- pitch high-lift propellers located upstream of the wing leading edge for lift augmentation at low speeds. These high-lift propellers are only required at low speeds, and to reduce drag, the propeller blades are folded conformally along the nacelles at other operating conditions. The method of designing the high-lift blades permits several variations of blade cross-section placement along the nacelle surface and a comparative performance analysis was needed to determine if any particular design showed significant benefits. We analyzed the performance of three conformal high-lift propeller designs and compared them to that of a non-conformal baseline propeller to establish both the benefit of stowable blades and the value of each variation. In this study, we first performed a drag analysis of each design in the stowed configuration at the X-57 cruise speed and altitude to determine the drag benefits of each conforming method. Then, among blade designs we compared the thrust, power, and lift for a given input shaft speed to establish any performance losses from the baseline. This analysis shows that the conformal blade designs do not have any appreciable performance losses compared to the baseline blades. Moreover, although the drag in the cruise condition is significantly less than for the non-folding baseline, the drag benefits of each conforming blade approach are similar and the value of each approach largely depends on the ease of integration into the nacelle. This paper presents the results of these studies and discusses the benefits and drawbacks of implementing the conformal blade designs. Specifically, we demonstrate that folding, conformal propeller blades contribute significantly less to cruise drag when compared to windmilling, with an increase relative to a. We also show a less than 1% difference in performance formal, folding propellers and the non-conforming baseline propeller

The field and the stage pugilism, combat performance and professional wrestling in England: 1700 – 1980

Speaking to a local radio station in the 1960s, with the glitz, glitter and glamour of televised professional wrestling at its height, one old, retired Cumbrian wrestler declared that ‘wrestling…was a game for the field not the stage’. This statement, condensed and potent as it is, could stand in for the questions this thesis asks and seeks to answer: why did wrestling develop as a professional, performed ‘sporting entertainment’? To answer this question, existing theories of social and sports history are combined with cultural studies methods and applied to Pierre Bourdieu’s notion of fields. Chapters one and two surveys the birth of a fielded society and the growth of spectator and professional sport as part of a wider cultural field in the eighteenth and early nineteenth centuries. Considering many sports during this time had relationships with the theatre, circus and fairground, the seemingly logical expansion of professional sport was closer to that of professional wrestling. Sport, however, did not develop in this way. Chapter three explore the reasons for this and posits that the genesis of the sporting field, demonstrated by the growth of sporting bodies and the perpetuation of amateur ideal, dominated the field. Control of wrestling, however, for various reasons, was not gained in this manner. Chapter four examines the consequences of this when professional wrestling became a fully performed sport in the interwar years. Finally, chapter five assesses the relationship between the sporting field and television in the late twentieth century. Wrestling as a ‘sporting entertainment’ is of interest precisely because it displays a ‘discarded possible’ of how professional sport may have grown had it not been for the institutions and ideologies active within the field during the late nineteenth- and early twentieth-century. It also demonstrates the often precarious nature of fields and concludes that sport’s meanings, pleasure and values are not as consistent as are first assumed

On the slice genus of links

We define Casson-Gordon sigma-invariants for links and give a lower bound of the slice genus of a link in terms of these invariants. We study as an example a family of two component links of genus h and show that their slice genus is h, whereas the Murasugi-Tristram inequality does not obstruct this link from bounding an annulus in the 4-ball.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol3/agt-3-30.abs.htm

Stock assessment of the Australian east coast tailor (Pomatomus saltatrix) fishery

Tailor, (Pomatomus saltatrix), is widely distributed in subtropical and temperate waters around the world. On the east coast of Australia, tailor occurs along the coasts of southern Queensland, New South Wales and Victoria and is considered a single genetic stock. This stock assessment analyses the Queensland and New South Wales component of the east coast stock. This stock assessment used the age-structured model from the previous assessment with an annual time step. Incorporated data spanned the period from 1945 to 2019 including total harvests, standardised catch rates and length and age information for Queensland and New South Wales commercial and recreational sectors. Model analyses suggested that spawning biomass was at around 51% of unfished biomass in 2019. This report provides estimates of sustainable harvests to ensure the fishery operates at sustainable levels, for commercial and recreational fishing, and supports the harvest strategy defined in Queensland’s Sustainable Fisheries Strategy 2017–2027 (Department of Agriculture and Fisheries 2017)

A Method for Designing Conforming Folding Propellers

As the aviation vehicle design environment expands due to the in flux of new technologies, new methods of conceptual design and modeling are required in order to meet the customer's needs. In the case of distributed electric propulsion (DEP), the use of high-lift propellers upstream of the wing leading edge augments lift at low speeds enabling smaller wings with sufficient takeoff and landing performance. During cruise, however, these devices would normally contribute significant drag if left in a fixed or windmilling arrangement. Therefore, a design that stows the propeller blades is desirable. In this paper, we present a method for designing folding-blade configurations that conform to the nacelle surface when stowed. These folded designs maintain performance nearly identical to their straight, non-folding blade counterparts

Age and growth of Pomatomus saltatrix in the south-western Pacific Ocean (eastern Australia), with a global comparison

Context: Pomatomus saltatrix is one of few globally distributed pelagic mesopredators that is exploited heavily throughout its range. Despite the implementation of management strategies, the south-western Pacific Ocean (eastern Australian) population has few published estimates of the key life-history parameters including growth. Aims: To estimate the age and growth of P. saltatrix in the south-western Pacific and compare these with the age and growth in other populations. Methods: Age estimates were made using whole otolith readings and an age–length key was used with a length frequency distribution to estimate the age structure of the population. Eight different growth models were compared within a Bayesian framework for both juvenile and overall growth. Key results: The Schnute growth equation provided the best fit for overall growth and yielded parameter values of a = −0.15, b = 2.56, Size-at-age 1 = 24.38-cm fork length (FL) and Size-at-age 4 = 47.36 cm FL. Conclusions: P. saltatrix in the south-western Pacific has a growth rate similar to that in other populations of P. saltatrix. Implications: Despite its geographically and genetically distinct populations, P. saltatrix demonstrates a generally consistent life-history strategy of fast growth and high mortality, except for the north-western Atlantic population, which has lower mortality

Homology of Distributive Lattices

We outline the theory of sets with distributive operations: multishelves and multispindles, with examples provided by semi-lattices, lattices and skew lattices. For every such a structure we define multi-term distributive homology and show some of its properties. The main result is a complete formula for the homology of a finite distributive lattice. We also indicate the answer for unital spindles and conjecture the general formula for semi-lattices and some skew lattices. Then we propose a generalization of a lattice as a set with a number of idempotent operations satisfying the absorption law.Comment: 30 pages, 3 tables, 3 figure

HDAC-mediated control of ERK- and PI3K-dependent TGF-β-induced extracellular matrix-regulating genes

Histone deacetylases (HDACs) regulate the acetylation of histones in the control of gene expression. Many non-histone proteins are also targeted for acetylation, including TGF-ß signalling pathway components such as Smad2, Smad3 and Smad7. Our studies in mouse C3H10T1/2 fibroblasts suggested that a number of TGF-ß-induced genes that regulate matrix turnover are selectively regulated by HDACs. Blockade of HDAC activity with trichostatin A (TSA) abrogated the induction of a disintegrin and metalloproteinase 12 (Adam12) and tissue inhibitor of metalloproteinases-1 (Timp-1) genes by TGF-ß, whereas plasminogen activator inhibitor-1 (Pai-1) expression was unaffected. Analysis of the activation of cell signalling pathways demonstrated that TGF-ß induced robust ERK and PI3K activation with delayed kinetics compared to the phosphorylation of Smads. The TGF-ß induction of Adam12 and Timp-1 was dependent on such non-Smad signalling pathways and, importantly, HDAC inhibitors completely blocked their activation without affecting Smad signalling. Analysis of TGF-ß-induced Adam12 and Timp-1 expression and ERK/PI3K signalling in the presence of semi-selective HDAC inhibitors valproic acid, MS-275 and apicidin implicated a role for class I HDACs. Furthermore, depletion of HDAC3 by RNA interference significantly down-regulated TGF-ß-induced Adam12 and Timp-1 expression without modulating Pai-1 expression. Correlating with the effect of HDAC inhibitors, depletion of HDAC3 also blocked the activation of ERK and PI3K by TGF-ß. Collectively, these data confirm that HDACs, and in particular HDAC3, are required for activation of the ERK and PI3K signalling pathways by TGF-ß and for the subsequent gene induction dependent on these signalling pathways