bluuebunny/crossref_metadata_2025 huggingface dataset:
The United Kingdom’s contributions to the development of aeronautics Part 4. The origins of the jet age
Authors: Ackroyd J. A. D.
Published: July 2022

Despite the common title of this series of papers, the specific area into which we now move originated on a more global scale than the title suggests. Thus in the spirit of the plan set down at the outset for this review,vizthat major ideas from abroad must be included, contributions from such countries as France, Germany and the United States here warrant greater prominence.

In Part 3 of this review we surveyed the development within Britain of the stress-skinned streamlined monoplane. Since the 1920s increasing numbers within Britain’s government research establishments, the universities and industry had been actively promoting this advance. Nonetheless, the practical hardware’s eventual emergence by the mid-1930s was largely driven by industry’s need for greater aerodynamic efficiency and a desire to excel. Thus record-breaking attempts, events such as the Schneider Trophy and MacRobertson races, all provided the impetus for this. So, too, did the commercial pressure of a new generation of American airliners and, for those astute enough to interpret them as such, the alarum calls of an impending Second World War. As a result of the appreciable decrease in drag coefficient achieved, coupled to a massive improvement in piston engine power, military aircraft, in particular, proved capable of flying not only further and higher but also dramatically faster. A further consequence, however, was that certain wartime high-speed fighter aircraft began to encounter serious, even fatal, compressibility effects as their enhanced speeds in dives reached subsonic critical Mach number conditions.
Computational simulation of wing rock in three degrees-of-freedom for a generic fighter with chine-shaped forebody
Authors: Saad A. A. , Liebst B. S.
Published: July 2022

Modern fighter aircraft have been associated with lateral self-excited limit cycle oscillation known as ‘wing rock’. Simulations of wing rock have been encouraged to develop a complete understanding of the fluid mechanism that triggers and drives the oscillation, as well as for prediction purposes. Previous simulations of wing rock in wind/water tunnels were almost exclusively limited to a single degree-of-freedom in roll, due to the difficulty encountered in mounting the model to freely oscillate in more than one degree-of-freedom. Numerical simulations, utilising computational fluid dynamics, were also limited to roll-only degree-of-freedom. The loss of simulation accuracy due to the reduction of the actual wing rock degrees-of-freedom to roll-only has not as yet been fully investigated. In this study wing rock is numerically simulated in three degrees-of-freedom: roll, sideslip, and vertical motion for a generic fighter model. The unsteady Euler equations are coupled with the rigid-body dynamic equations through an innovative sub-iteration algorithm to simultaneously solve the coupled equations. The effect of including the sideslip and vertical degrees-of-freedom was found to delay the onset angle-of-attack of wing rock by 5° and reduce the limit cycle amplitude by about 50% with the frequency remained almost unchanged.
Mechanical and electromagnetic behaviour of auxetic honeycomb structures
Authors: Scarpa F. , Smith F. C. , Chambers B. , Burriesci G.
Published: July 2022

In this work a combined analysis of the out-of-plane mechanical and the electromagnetic properties of auxetic re-entrant honeycombs is performed. Experimental and numerical simulations are carried out to evaluate the correlation between the anisotropicity of the transverse mechanical properties (shear and compressive modulus) and the permittivity tensor of auxetic honeycombs. The results are evaluated to assess the feasibility of this kind of cellular solid for electromagnetic absorption and window applications with high structural integrity performance.
Staged combustor optimisation in the environmental aircraft envelope
Authors: Wulff A. , Hourmouziadis J.
Published: July 2022

A new semi-empirical one-dimensional approach for the prediction of aeroengine combustor emissions is presented. The model features a high level of versatility, resulting in a remarkable correlation quality of measurement data of different combustors. This combustion model was modified to reflect the design characteristics of staged combustors. After implementation in an optimisation procedure it was used for staged combustor design studies. For a typical aeroengine application an optimised combustor design was derived with respect to a predefined criteria. Potential exchange rates of combustion efficiency versus NOx emissions by rematching the fuel split for different operating conditions at extreme points of the environmental envelope (ISA/hot day/cold day) of a modern commercial aircraft were investigated. Conclusions regarding the suitable operation of the combustor were drawn. Finally the effect of changed design constrains on the optimisation result was investigated.
Autonomous behavioural algorithm for space applications
Authors: Radice G. , McInnes C. R.
Published: July 2022

The purpose of this paper is to present a new approach in the concept and implementation of autonomy for autonomous spacecraft. The one true ‘artificial agent’ approach to autonomy requires the spacecraft to interact in a direct manner with the environment through the use of sensors and actuators. Rather than using complex world models, the spacecraft is allowed to exploit the dynamics of its environment for cues as to appropriate actions to take to achieve its mission goals. The particular artificial agent implementation used here has been inspired by studies of biological systems. The so-called ‘cue-deficit’ action selection algorithm considers the spacecraft to be a non-linear dynamical system with a number of observable states. Using optimal control theory a set of rules is derived which determine which of a finite repertoire of behaviours the spacecraft will perform. A simple model of a single imaging spacecraft in low polar Earth orbit is used to demonstrate the algorithm.
The ‘air side’ of future warfare – military aeronautics
Authors: Bushnell D. M.
Published: July 2022

The ongoing revolutions in information, biological, energetics and nano technologies are changing the nature and equipment of warfare. This is particularly true in military aeronautics. In the nearer term aircraft are becoming increasingly ‘uninhabited’ (UCAVs, UAVs etc.) enabled by the IT revolution, with multitudinous accompanying benefits in terms of affordability, survivability, redefinition of ‘risk’ and lethality. THE issue for such aircraft is enhanced persistence and increased range within the context of the overall system metrics. In the longer term the increasingly capable worldwide ‘sensor web’ will place at risk all air vehicles, in or out of theatre and whether or not they are ‘stealthy’. This, combined with advanced conventional weapons, high energy density material powered EMP (electro-magnetic-pulse) weapons and affordable swarms of ‘brilliant’ munitions will probably require yet another re-definition of military aeronautics, perhaps as survivable (hardened) hypersonic, global range, boost-glide devices.
Materials for airframes
Authors: Flower H. M. , Soutis C.
Published: July 2022

The prediction of the future is always a relatively uncertain process. The only certain fact is that the prediction is unlikely to be wholly accurate. Even the prediction of trends following examination of past performance will be uncertain regarding the future rate of advance and may be entirely upset by new discoveries and their application. This is as true for examining the future of airframe materials as it is for prediction of economic growth, which itself significantly affects the development of materials technology in the aircraft industry. However, 100 years of powered manned flight does give a solid database from which to begin. In that period airframes have moved from wood, wire and canvas, through to riveted and stressed skin metal structures to adhesively bonded polymer composites. In each case the use of new materials is associated with a change in fabrication methods and it may be confidently anticipated that this will remain true in the future. This fact accounts for a justified conservatism in embracing new materials, not simply because of the need to develop experience and confidence in them, but also because of the costs associated with new constructional methods entailed in their application. It also, in part, accounts for the generally slower pace of application of new materials relative to what is initially predicted: the other powerful brake being the state of the economy and the market for new aircraft at any particular time. The early prediction of the demise of aluminium and its replacement by polymer composites made in the 1980s being a case in point, while the failure of alloys containing lithium to replace conventional aluminium alloys had more to do with cost and decreasing fuel prices than any alloy development problems. It can, however, be expected that, as in the twentieth century, military aircraft will exploit larger mass fractions of advanced materials and at earlier dates than civil transport aircraft, given their very different operational requirements and much shorter design lives. The likely advent of unmanned combat aircraft may well accentuate this difference.
Simulation – the real world of the future!
Authors: Curnutt R. A.
Published: July 2022

Flight simulation has definitely kept pace with powered flight through the past century, and its future is seemingly unlimited. To understand where the future might lie, it is important to consider the current situation, in terms of training, engineering and entertainment industry (consumer) uses of simulation. As will be shown, simulation has become a critical tool for use in aircraft design and validation, as well as playing a key and well-known role in flight training. Of course, entertainment uses of simulation are becoming more common; ranging from PC-based games to rides at the mall. By reflecting on these uses of simulation and the drivers behind them, it is possible to project into the future; both near-term, and well into the next 100 years. The projections will hopefully lead to healthy discussion and further speculation in academic and industry forums – and ultimately to new and better ideas.
Life extension of impact damaged honeycomb sandwich panels
Authors: Aitken R. R. , Horrigan D. P. W. , Moltschaniwskyj G.
Published: July 2022

The assessment of damage due to impacts in composite sandwich panels and the component life reductions associated with such damage is becoming increasingly important within the aerospace industry. This study analyses minimum gauge, non-metallic honeycomb wing panels subject to impact damage. In all instances the damage is caused by ‘soft body’ impactors travelling at elevated velocities to simulate bird strike and other soft debris. The damage formed during these impacts is shown to be large in plan area but shallow and primarily causes crushing of the core in a thin layer. Loading of the panels after impact has been performed to determine the reduction in load carrying capacity and associated failure mechanisms. Damage due to soft body impact is shown to be very different to the classical rigid body impact upon which current repair schemes are based. As a result in many applications the use of current repair schemes may be inappropriate. The viability of new repair techniques is discussed with particular attention to the prevention of failure mechanisms due to loading after impact.
Passive control of shock wave–boundary-layer interactions
Authors: Gibson T. M. , Babinsky H. , Squire L. C.
Published: July 2022

The passive control of a shock wave-boundary-layer interaction involves placing a porous surface beneath the interaction, allowing high pressure air from the flow downstream of the shock wave to recirculate through a plenum chamber into the low pressure flow upstream of the wave.

The simple case of a normal shock wave at a Mach number of 1·4 interacting with the turbulent boundary layer on a flat wall is investigated both experimentally and numerically. The experimental investigation made use of holographic interferometry, while the computational section of the investigation made use of a Navier-Stokes code to derive pressure gradients, boundary-layer properties and total pressure losses in the interaction region. It is found that the structure of shock wave-boundary-layer interactions with passive control consists of a leading, oblique shock wave followed by a lambda foot. The oblique wave originates from the upstream end of the porous region, and its strength is determined by the magnitude of the local blowing velocities. The shape of the lambda foot depends on the position of the main shock relative to the control region, resembling an uncontrolled foot when the main shock wave is towards the downstream end of the porosity, but becoming increasingly large as the shock moves upstream and eventually merging with the leading, oblique shock to form a single, large, lambda structure.

Improved forms of passive control are suggested based on the findings of this investigation, including the use of passive control systems which incorporate streamwise variations in the level of porosity.
The design, construction and operation of the noise test facility at the National Gas Turbine Establishment
Authors: Martlew D. L. , Hawkins J. M. , Brooking R. L. , Kennedy A. S.
Published: July 2022

In the period since the inception of civil jet transport, during which a dramatic increase in travel and commerce by air has taken place, the research and development directed towards the containment and reduction of aircraft noise has spread across a steadily broadening front. The noise of the simple jet engines which propelled the first civil transport aircraft was almost entirely due to the high exhaust jet velocities that were used to obtain thrust from comparatively small mass flows. This is illustrated in Fig. 1(a), where it is seen that noise from other sources, such as the compressor and turbine, is comparatively insignificant. Thus aero engine noise research in the late fifties and early sixties was concentrated mainly on the prediction of jet noise and the development of noise-reducing propelling nozzles. It was not until bypass engines began to appear, with higher propulsive efficiencies resulting from lower exhaust jet velocities and higher mass flows, that the noise of their larger compressors drew attention to the turbomachinery as an additional source requiring investigation.
Determination of the damping of a system using a planimeter
Authors: Russell J. B.
Published: July 2022

A problem, commonly met in scientific and engineering experiments, is the determination of the damping of a system, given a recorded trace (such as that from a uv recorder) of the free damped oscillation following a disturbance. The simplest and most tedious method is to plot the logarithm of the peak amplitude at each half cycle against cycle number. Other methods have been given by Hogley and Gimmestad, Bratt and Wilcox and Crawford. However, the problem is so common, and the experiments and methods of recording the results so diverse, it is felt that a further method could find a place in the range of those available.
The technology and economics of air transport in its next phase
Authors: Wilkinson K. G.
Published: July 2022

It is now 72 years since the Wright Brothers made the first controlled flights with a manned heavier-than-air machine, and I am deeply conscious of the great honour conveyed by the invitation to deliver this 64th Memorial Lecture commemorating their great achievement.

Their research and development work provides a classic model of a combination of the scientific and practical approaches to the solution of a major problem. However, it is fascinating to look back to those very different days at the turn of the century, and see how incompletely they foresaw all the consequences of their own efforts. Contemporary evidence suggests that their vision was confined to certain secondary uses of the aeroplane, such as military reconnaissance, sport and exploration.
The assessment of noise, with particular reference to aircraft
Authors: Robinson D. W.
Published: July 2022

It is now some 20 years since aircraft noise became a significant public nuisance and every conceivable aspect of the problem has been scrutinised and discussed in a vast literature. The scope of the present paper, in relation to this broad canvas, will appear extremely narrow. Nothing will be found herein about such important questions as the influence of noise on the development of aviation, engine technology, operational procedures, reduction of noise by acoustical means, the economics of air transport, regulatory action, or the planning of airports. It is only necessary to make slight reference to these matters to sketch the framework within which a system of measurement and assessment of noise has developed. The circumscribed nature of these aspects, unfortunately, does not mean that they can be dealt with briefly or summarised easily.
A brief study of airspeed fluctuations on the landing approach in relation to reported and measured surface wind conditions
Authors: Terry G.
Published: July 2022

The conventional landing technique for most aircraft involves a constant speed approach along a well denned glidepath. The speed is selected to maintain an adequate margin above the stall. Allowance is made for wind conditions. At the beginning of the landing approach a pilot is quoted a nominal mean surface windspeed and direction by radio contact with the airfield control tower. The local controller is provided with a conventional meteorological office dial-reading anemometer but, because of other duties, does not monitor it continuously.
The independence of upper and lower wing flows at supersonic speeds
Authors: Squire L. C.
Published: July 2022

Advances in computational methods are producing a need for accurate and detailed experimental results for test cases. At the same time economic trends force many of these experiments to be made in small wind tunnels. In some cases the small scale of the model does not provide enough space for the instrumentation and so the model must be distorted from the ideal shape. This paper is concerned with one aspect of this problem, that is, with the need to make wings thicker than required, either for strength or to provide volume for pressure tubes and other measuring devices. In particular the paper deals with the conditions under which the pressures measured on the flat surfaces of wings with bevelled or triangular cross-sections as shown in Figs. 1(b) and 1(c) are a good representation of the pressures which would be measured on the corresponding flat surface of thin wings (Fig. 1(a)). This problem has been touched on in a number of papers reporting experimental results but it does not appear to have been tackled systematically. The discussion of this paper is based on these earlier tests and on some new test results.
Airline managerial efficiency
Authors: Pearson Roy J.
Published: July 2022

Airline efficiency is not a simple concept which can be measured by a single parameter. It is an amalgam of complex relationships which are in turn the results of many different activities. Probably because of this, efficiency criteria are mostly looked at in isolation which results in the overall concept of airline efficiency remaining nebulous. In fact the airline efficiency concept possesses a number of different but inter-related aspects. Figure 1 is a diagrammatic representation of the airline efficiency concept and depicts the various aspects and relationships which go to form it. This diagram portrays, in basic form, the major forces involved.
The development of a composite propeller blade with a carbon fibre reinforced plastics spar
Authors: Colclough W. J. , Russell J. G.
Published: July 2022

Three basic problems encountered in the use of propellers on hovercraft are erosion, corrosion and noise. The tip velocity of a 9 ft diameter hovercraft propeller can exceed Mach 0·8, giving rise to fairly high noise levels. When operating over shallow water the propeller may run in a fine suspension of sand and sea water, which at these high speeds is akin to operating in a highly corrosive vapour blast cabinet.
The advantages of adjoint-control transformations when determining optimal trajectories by Pontryagin's Maximum Principle
Authors: Dixon L. C. W. , Biggs M. C.
Published: July 2022

The many methods by which Pontryagin's Maximum Principle is applied in optimal control problems can be divided into two groups, termed direct and indirect. The indirect methods use the conditions required for mathematical optimality as the starting point and attempt to satisfy the boundary conditions. The direct methods on the other hand satisfy the equations of motion and boundary conditions and then attempt to improve the performance index. It has been reported that the direct methods, while normally converging from very bad initial assumptions, have the inherent disadvantage of very slow convergence in the neighbourhood of the optimal solution and, so, complicated second order methods have recently been devised.
On the use of the Preston tube in elliptical ducts
Authors: Duffy J. , Cain D.
Published: July 2022

The principle of wall similarity expressed by a universal logarithmic inner law relationship is well established for turbulent flow in circular pipes. The validity of Preston's original hypothesis for the measurement of turbulent skin friction depends upon the existence of wall similarity. Although Preston's hypothesis appears to be correct in general it has been found that his calibration for the wall pitot tube was incorrect. Extensive observations by Head and Rechenberg showed some discrepancy. Later work by Patel on the measurement of skin friction in three circular pipes covering a much larger experimental range has led to a modified calibration.
Helicopters in the Royal Navy
Authors: Bryson L. B. , Heenan F. E. , Johnson C. A.
Published: July 2022

“An historian is a prophet in reverse”.

Friedrich Von Schiegel

The advantages to a Navy of an aircraft which can operate from a relatively small deck area are enormous and it is not surprising that the British as a maritime nation were in the forefront of the development of rotary wing aircraft for use at sea. However, the first man to land a rotary wing aircraft on a ship other than an aircraft carrier was an ex-Royal Air Force Officer R. A. C. Brie and the ship was the Italian cruiserFiume.
A Derivation Procedure for the Dynamic Flexibility Matrix of a Triangular Bending Element
Authors: Robinson J.
Published: July 2022

Of the two main finite element approaches, the displacement method has progressed more rapidly than the force method in the area of element representation. Many authors have contributed to the displacement method with both static and dynamic stiffness matrices for beam elements, plane stress elements and plate bending elements. The plane stress and bending elements being rectangular, triangular or quadrilateral in form. A dynamic stiffness matrix consists of a static stiffness matrix and a mass matrix. In the force method, .static flexibility matrices have been developed for beam elements and plane stress elements. However, static flexibility matrices for plate bending elements have only recently been published (Kaufman and Hall, Morley, Robinson, Przemieniecki). For the past few years, the author has been investigating the rank force method for structural vibration analysis. In ref. 6 a dynamic flexibility matrix is presented for a beam element. This matrix consists of a static flexibility matrix and an inverse mass matrix. Ref. 5 contains the derivation of a dynamic flexibility matrix for a rectangular plate element in bending, twisting and shear. The author, in collaboration with Petyt, demonstrated how a dynamic stiffness and flexibility matrix can be extended to include material damping.
Shock Patterns for Simple Caret Wings
Authors: Venn J. , Flower J. W.
Published: July 2022

The equations defining compressible flow are sufficiently complicated to preclude general analysis, but, in particular cases, can often be simplified and manipulated into a form amenable to solution. Problems connected with aircraft have, in the past, usually fallen into this category, where the non-linear equations can be simplified to a linear form and reasonably accurate solutions deduced. At hypersonic speeds, however, the more usual assumptions become invalid, no reasonable simplification can be made, and, except in certain specialised cases, no solutions can be deduced. Hence the problem of deriving the flow pattern around some specified shape becomes, in general, insoluble. The simple caret wing was proposed seven years ago by Nonweiler to avoid such difficulty. His elegant idea was to reverse the normal process of deducing the flow field round a given body shape, and instead to deduce body shapes that would generate specific, simple, flow patterns. From known flow fields lifting bodies may be obtained, by replacing .streamlines with solid surfaces, and the caret wing is one example. Nonweiler’s original notion has sin:e been extended by a number of people.
Direct Lift Control
Authors: Pinsker W.J. G.
Published: July 2022

Control of flight is essentially control of lift. When one proposes—as we shall do here—to tamper with one of the most fundamental principles of aircraft control, it is evident that this may have far reaching repercussions and that such a venture cannot therefore be undertaken lightly. The elevator has been the primary longitudinal control since the earliest pioneering days and has served the aircraft well from its modest beginnings to this age of supersonic flight. Why do we want to change and what do we want to take its place; how will the pilot react to an altogether novel way of controlling the aeroplane? These are the questions one is bound to ask when direct lift control is suggested as an alternative and these are the questions which we shall attempt to answer here.
Attitude Dynamics of a Gravity Orientated Satellite under the Influence of Solar Radiation Pressure
Authors: Flanagan R. C. , Modi V. J.
Published: July 2022

For many space applications, such as communication, weather, military, and scientific experiment satellites scanning precise regions, it is necessary to maintain a satellite in a fixed orientation relative to the earth. Unfortunately, a correctly positioned satellite deviates with time from this preferred orientation due to perturbing environmental forces. This explains considerable interest in libra-tional stability study in recent times.

Among the numerous methods developed for librational control, a passive technique depending on the gradient of the gravitational field has gained attention. Depending on the orbital distance, environmental effects, such as, aerodynamic, radiation, and magnetic torques, become significant compared to the gravity-gradient restoring moment. A need to determine the influence of these disturbing forces is thus evident.
Aerofoil nose shapes delaying leading-edge separation
Authors: Tuck E. O. , Dostovalova A.
Published: July 2022

If an aerofoil of chord c has a parabolic nose with radius of curvature r, and is placed at angle-of-attack α to a stream, the laminar boundary layer on its upper surface remains unseparated for α<0.8l8. In the present paper we consider some smooth local modifications to the leading edge. Symmetric modifications of the nature of local sharpening of the nose can improve this result to at least α<0.897. Further improvements are possible for unsymmetrical (e.g. drooped) noses, and an example of a ‘drooped’ nose with α<0.912 is shown.
Challenges in the better, faster, cheaper era of aeronautical design, engineering and manufacturing
Authors: Murman E. M. , Walton M. , Rebentisch E.
Published: July 2022

'Better, faster, cheaper’ (BFC) emerged in the 1990s as a new paradigm for aerospace products. In this paper, we examine some of the underlying reasons for BFC and offer some thoughts to help frame the thinking and action of aerospace industry professionals in this new era. Examination of literature on industrial innovation indicates that aeronautical products have evolved to a ‘dominant design’ and entered the ‘specific phase’ of their product life cycle. Innovation in this phase centers on: incremental product improvement, especially for productivity and quality; process technology; technological innovations that offer superior substitutes. The first two of these are aligned with BFC objectives.

The concepts of ‘value’ and ‘best lifecycle value’ are introduced as conceptual frameworks. Value is offered as a metric for BFC. Risk management is intimately tied to achieving value and needs to be integrated into aeronautical processes. The process technology area is addressed by considering ‘lean’ practices for design, engineering and manufacturing. Illustrative results of process improvements from the seven-year Lean Aerospace Initiative research programme at MIT indicate opportunities to achieve BFC. Concluding remarks offer some challenges to industry, government and academics in aeronautical design, engineering and manufacturing.
Flight simulation - past, present and future
Authors: Allerton D. J.
Published: July 2022

This paper outlines the development of flight simulators used in civil training, military training and in engineering simulation. It describes the evolution of flight simulators and the typical architecture of a modern flight simulator. The technical innovations, which have occurred in modelling, motion systems and visual systems are reviewed. The paper also reviews the transfer of training in flight simulation, the application of simulation to engineering design and outlines problems which are encountered in flight simulation. The paper concludes by reviewing the current trends in flight simulation.
The External Aerodynamics of Hovercraft
Authors: Andrews E. J.
Published: July 2022

By way of introduction to my paper and to place its subject matter in perspective, I would like to refer to a paper by A. Silverleaf, Deputy Director of NPL, Teddington, entitled A Review of Hovercraft Research in Britain (published in the JOURNAL, pp. 1019–1028, December 1968). Mr. Silverleaf presented a comprehensive review of research programmes at national establishments, in industry, and at universities. Although he did not specifically mention the College of Aeronautics by name, Mr. Silverleaf briefly commented on the research programme into external aerodynamics that is being conducted at the College.
An investigation of dynamic stall onset on a pitching wing
Authors: Ferrecchia A. , Coton F. N. , Galbraith R. A. McD. , Green R. B.
Published: July 2022

This paper presents an examination of dynamic stall onset on both a rectangular wing and a nominally two-dimensional aerofoil with the same cross-section. The intention is to determine the extent to which the onset of dynamic stall is changed in the three-dimensional case. To do this, three different criteria are applied to measured pressure data to identify both the onset of the stalling process and the formation of the dynamic stall vortex. It is shown that examination of the vorticity flux in the vicinity of the leading edge provides a means of determining vortex formation in the absence of strong three-dimensional effects. It is also shown that this technique is not applicable on outboard sections of the rectangular wing where the phasing of dynamic stall onset with respect to the leading edge response is altered by the three-dimensionality of the flow. It is concluded that the application of two-dimensional stall onset criteria is inappropriate under such conditions.
Non-linear analysis of stall flutter based on the ONERA aerodynamic model
Authors: Beedy J. , Barakos G. , Badcock K.J. , Richards B.E.
Published: July 2022

This paper presents a simple and efficient way of calculating stall flutter using the ONERA aerodynamic model. At first, the model is presented along with a solution technique based on the harmonic balance method. The parameters of the model are estimated using data either from experiments or CFD calculations and optimised using the Levenberg-Marquardt algorithm. The aerodynamic model is then coupled with a structural one using the Rayleigh-Ritz formulation and a solution technique is devised based on the Newton- Raphson method. Finally the model is used to ‘fit’ aerodynamic loads of oscillating aerofoils generated using CFD. The aeroelastic analysis of a helicopter blade is finally undertaken using material properties found in the literature. The model appears to be robust and efficient and able to fit the unsteady aerodynamics of various cases. The proposed aeroelastic analysis was also found to be efficient and capable of providing adequate results for preliminary analysis of stall flutter.
Selenium intakes and plasma selenium of New Zealand toddlers: secondary analysis of a randomised controlled trial
Authors: Daniels Lisa , Haszard Jillian J. , Gibson Rosalind S. , Taylor Rachael W. , Fleming Elizabeth A. , Miller Jody C. , Thomson Christine D. , Heath Anne-Louise M.
Published: July 2022

Little is known about Se intakes and status in very young New Zealand children. However, Se intakes below recommendations and lower Se status compared with international studies have been reported in New Zealand (particularly South Island) adults. The Baby-Led Introduction to SolidS (BLISS) randomised controlled trial compared a modified version of baby-led weaning (infants feed themselves rather than being spoon-fed), with traditional spoon-feeding (Control). Weighed 3-d diet records were collected and plasma Se concentration measured using inductively coupled plasma mass spectrometry (ICP-MS). In total, 101 (BLISS n 50, Control n 51) 12-month-old toddlers provided complete data. The OR of Se intakes below the estimated average requirement (EAR) was no different between BLISS and Control (OR: 0·89; 95 % CI 0·39, 2·03), and there was no difference in mean plasma Se concentration between groups (0·04 μmol/l; 95 % CI −0·03, 0·11). In an adjusted model, consuming breast milk was associated with lower plasma Se concentrations (–0·12 μmol/l; 95 % CI −0·19, −0·04). Of the food groups other than infant milk (breast milk or infant formula), ‘breads and cereals’ contributed the most to Se intakes (12 % of intake). In conclusion, Se intakes and plasma Se concentrations of 12-month-old New Zealand toddlers were no different between those who had followed a baby-led approach to complementary feeding and those who followed traditional spoon-feeding. However, more than half of toddlers had Se intakes below the EAR.
Characterization of complete mitochondrial genome and ribosomal operon forCarassotrema koreanumPark, 1938 (Digenea: Haploporidae) by means of next-generation sequencing data
Authors: Ivashko Y.I. , Semenchenko A.A. , Solodovnik D.A. , Atopkin D.M.
Published: July 2022

We obtained new data on the complete mitochondrial DNA (mtDNA) and the ribosomal operon of the trematodeCarassotrema koreanum(Digenea: Haploporata: Haploporidae), an intestinal parasite ofCarassius auratus, using next-generation sequencing. The mtDNA ofC.koreanumcontained 13,965 bp, including 12 protein-coding genes, two ribosomal genes, 22 transport RNA (tRNA) genes and a non-coding region. The ribosomal operon ofC.koreanumwas 10,644 bp in length, including ETS1 (1449 bp), 18S ribosomal RNA (rRNA) gene (1988 bp), ITS1 ribosomal DNA (rDNA) (558 bp), 5.8S rRNA gene (157 bp), ITS2 rDNA (274 bp), 28S rRNA gene (4152 bp) and ETS2 (2066 bp). Phylogenetic analysis based on mtDNA protein-coding regions showed thatC.koreanumwas closely related toParasaccocoelium mugili, a species from the same suborder Haploporata. Bayesian phylogenetic tree topology was the most reliable and confirmed the validity of the Haploporata. The results of sequence cluster analysis based on codon usage bias demonstrated some agreement with the results of the phylogenetic analysis. In particular,Schistosomaspp. were differentiated from the other members of Digenea and the members of Pronocephalata were localized within the same cluster.Carassotrema koreanumandP.mugilifell within different clusters. The grouping ofC.koreanumandP.mugiliwithin the same cluster was obtained on the basis of frequencies of 13 specified codons, of which three codon pairs were degenerate. A similarity was found between two haploporid species and twoDicrocoeliumspp. in the presence of TTG start codon of the mitochondrialnad5 gene. Our results confirmed the taxonomical status of the Haploporata identified in the previous studies and revealed some characteristic features of the codon usage in its representatives.
Integrative taxonomy confirms the presence of the enigmaticLysmata olavoiFransen, 1991 (Decapoda: Lysmatidae) in the Mediterranean Sea
Authors: Tanduo Valentina , Virgili Riccardo , Crocetta Fabio
Published: July 2022

The genusLysmataRisso, 1816 includes five species in the Mediterranean Sea, namely two well-known species with an Atlantic–Mediterranean distribution,L. seticaudata(Risso, 1816) andL. nilitaDohrn & Holthuis, 1950, and three additional species only known from single records. These areL. kempiChace, 1997 andL. vittata(Stimpson, 1860), alien species native to the Indo-Pacific region, andL. olavoiFransen, 1991, a poorly known species originally described from the Azores (Atlantic Ocean) and only reported three decades ago from the eastern parts of the basin. Based on an integrative taxonomic approach, we report the first finding of an ovigerous female ofL. olavoifrom Italy (Gulf of Naples, Tyrrhenian Sea) and the entire western Mediterranean, thus confirming the presence of this species in the basin and filling a wide gap in its published distribution. It is possible that this taxon was present in the Mediterranean for centuries but went overlooked or undetected due to cryptic habits, occupancy of still unexplored habitats, or misidentification with the highly similarL. seticaudata. Results of phylogenetic analyses confirm the exclusion ofL. olavoiby the major lysmatid groups and underline the necessity of multilocus approaches to disentangle its correct phylogenetic position. As the species is still surrounded by a number of unsolved ecological and phylogenetic questions, further field and laboratory work is required to shed light on them.
What makes conservationists persevere? Resilience strategies at work
Authors: Loffeld Thirza A.C. , Black Simon A. , Carter Marianne , Sterling Eleanor , Humle Tatyana
Published: July 2022

Conservation professionals face cognitively and emotionally demanding tasks and a wide range of working conditions, including high levels of uncertainty (e.g. the socio-political contexts in which they must function, possible long hours and isolation from friends and family). Resilience (i.e. positive adaptation to professional challenges) can help individuals thrive in their roles. We interviewed 22 conservationists with professional experience working in low-income countries with high biodiversity and explored what helped and what hindered them in their work. We used thematic analysis to identify factors related to positive and negative psychological states and strategies to promote resilience at work. The results revealed factors that were associated with positive psychological states, including achievements and recognition for work. Organizational policies and administration, especially perceived unfairness regarding salaries, recruitment policies and promotion, were associated with negative psychological states, as were other factors related to the job context. Respondents shared their professional resilience strategies such as aligning work with one's values, and personal reflection and goal setting. We recommend that organizations support their employees in the process of building resilience by addressing basic needs and motivational factors.
Enabling personalization of a robotic surgery procedure via a surgery training simulator
Authors: Dede Mehmet İsmet Can , Büyüköztekin Tarık , Hanalioğlu Şahin , Işıkay İlkay , Berker Mustafa
Published: July 2022

Although robotic or robot-assisted surgery has been increasingly used by many surgical disciplines, its application in cranial or skull base surgery is still in its infancy. Master-slave teleoperation setting of these robotic systems enables these surgical procedures to be replicated in a virtual reality environment for surgeon training purposes. A variety of teleoperation modes were previously determined with respect to the motion capability of the surgeon’s hand that wears the ring as the surgeon handles a surgical tool inside the surgical workspace. In this surgery training simulator developed for a robot-assisted endoscopic skull base surgery, a new strategy is developed to identify the preferred motion axes of the surgeon. This simulator is designed specifically for tuning the teleoperation system for each surgeon via the identification. This tuning capability brings flexibility to adjust the system operation with respect to the motion characteristics of the surgeon.
Enabling multi-modal search for inspirational design stimuli using deep learning
Authors: Kwon Elisa , Huang Forrest , Goucher-Lambert Kosa
Published: July 2022

Inspirational stimuli are known to be effective in supporting ideation during early-stage design. However, prior work has predominantly constrained designers to using text-only queries when searching for stimuli, which is not consistent with real-world design behavior where fluidity across modalities (e.g., visual, semantic, etc.) is standard practice. In the current work, we introduce a multi-modal search platform that retrieves inspirational stimuli in the form of 3D-model parts using text, appearance, and function-based search inputs. Computational methods leveraging a deep-learning approach are presented for designing and supporting this platform, which relies on deep-neural networks trained on a large dataset of 3D-model parts. This work further presents the results of a cognitive study (n= 21) where the aforementioned search platform was used to find parts to inspire solutions to a design challenge. Participants engaged with three different search modalities: by keywords, 3D parts, and user-assembled 3D parts in their workspace. When searching by parts that are selected or in their workspace, participants had additional control over the similarity of appearance and function of results relative to the input. The results of this study demonstrate that the modality used impacts search behavior, such as in search frequency, how retrieved search results are engaged with, and how broadly the search space is covered. Specific results link interactions with the interface to search strategies participants may have used during the task. Findings suggest that when searching for inspirational stimuli, desired results can be achieved both by direct search inputs (e.g., by keyword) as well as by more randomly discovered examples, where a specific goal was not defined. Both search processes are found to be important to enable when designing search platforms for inspirational stimuli retrieval.
HPV vaccination and factors influencing vaccine uptake among people of Indian ancestry living in the United States
Authors: Ratnasamy Philip , Chagpar Anees B.
Published: July 2022

Approximately one-quarter of annual global cervical cancer deaths occur in India, possibly due to cultural norms promoting vaccine hesitancy. We sought to determine whether people of Indian ancestry (POIA) in the USA exhibit disproportionately lower human papilloma virus (HPV) vaccination rates than the rest of the US population. We utilised the 2018 National Health Interview Survey to compare HPV vaccine initiation and completion rates between POIA and the general US population and determined factors correlating with HPV vaccine uptake among POIA. Compared to other racial groups, POIA had a significantly lower rate of HPV vaccination (8.18% vs. 12.16%, 14.70%, 16.07% and 12.41%, in White, Black, Other Asian and those of other/mixed ancestry, respectively, P = 0.003), but no statistically significant difference in vaccine series completion among those who received at least one injection (3.17% vs. 4.27%, 3.51%, 4.31% and 5.04%, P = 0.465). Among POIA, younger individuals (vs. older), single individuals (vs. married), those with high English proficiency (vs. low English proficiency), those with health insurance and those born in the USA (vs. those born outside the USA) were more likely to obtain HPV vaccination (P = 0.018, P = 0.006, P = 0.029, P = 0.020 and P = 0.019, respectively). Public health measures promoting HPV vaccination among POIA immigrants may substantially improve vaccination rates among this population.
The human LSm1-7 proteins colocalize with the mRNA-degrading enzymes
Dcp1/2 and Xrn1 in distinct cytoplasmic foci
Authors: INGELFINGER DIERK , ARNDT-JOVIN DONNA J. , LÜHRMANN REINHARD , ACHSEL TILMANN
Published: July 2022

Sm and Sm-like (LSm) proteins form heptameric complexes that are
involved in various steps of RNA metabolism. In yeast, the Lsm1–7 complex
functions in mRNA degradation and is associated with several enzymes of this
pathway, while the complex LSm2–8, the composition of which largely overlaps
with that of LSm1–7, has a role in pre-mRNA splicing. A human gene encoding
an LSm1 homolog has been identified, but its role in mRNA degradation has
yet to be elucidated. We performed subcellular localization studies and
found hLSm1 predominantly in the cytoplasm. However, it is not distributed
evenly; rather, it is highly enriched in small, discrete foci. The
endogenous hLSm4 is similarly localized, as are the overexpressed proteins
hLSm1–7, but not hLSm8. The foci also contain two key factors in mRNA
degradation, namely the decapping enzyme hDcp1/2 and the exonuclease hXrn1.
Moreover, coexpression of wild-type and mutant LSm proteins, as well as
fluorescence resonance energy transfer (FRET) studies, indicate that the
mammalian proteins hLSm1–7 form a complex similar to the one found in yeast,
and that complex formation is required for enrichment of the proteins in the
cytoplasmic foci. Therefore, the foci contain a partially or fully assembled
machinery for the degradation of mRNA.
Naf1p is a box H/ACA snoRNP assembly factor
Authors: FATICA ALESSANDRO , DLAKIĆ MENSUR , TOLLERVEY DAVID
Published: July 2022

Box H/ACA small nucleolar ribonucleoprotein particles (snoRNPs) contain
four essential proteins, Cbf5p, Gar1p, Nhp2p, and Nop10p, each of which,
with the exception of Gar1p, is required for box H/ACA snoRNA accumulation.
Database searches identified a novel essential protein, which we termed
Naf1p, with a region of homology to the RNA-binding domain of Gar1p and
other features in common with hnRNP-like proteins. Naf1p is localized to the
nucleus and is not a stable component of the H/ACA snoRNPs, but it is
required for the accumulation of all box H/ACA snoRNAs. This requirement is
not at the level of snoRNA transcription initiation or termination. Naf1p
shows in vitro RNA-binding activity and also binds directly to Cbf5p and
Nhp2p. Naf1p was shown to bind to the CTD in vivo in a two-hybrid assay, and
the phosphorylated CTD, but not the nonphosphorylated CTD, was shown to
precipitate tagged Naf1p from a cell lysate. We propose that Naf1p is
recruited to the CTD of RNA polymerase II and binds to nascent box H/ACA
snoRNAs promoting snoRNP assembly.