bluuebunny/crossref_metadata_2025 huggingface dataset:
A Probabilistic Approach to Aeronautical Research and Development
Authors: Harvey R. A.
Published: July 2022

This paper is a revised version of a contribution towards the work of the Society's Future Policy Committee's Working Party on Effectiveness in R & D. An abbreviated version of the Working Party's report was published in the September 1969 Journal.

The R & D process in any sphere exhibits features of uncertainty in many of its phases and it therefore seems appropriate to examine aeronautical R & D from a probabilistic viewpoint. Before discussing the origins and treatment of these uncertainties it is necessary to define Research and Development in the aeronautical context and to state its aims as seen by the author.
Some Correlations for the Turbulent Boundary Layer on a Flat Plate
Authors: Chappell P. D.
Published: July 2022

Spalding and Chi have shown that their method of predicting the skin friction and momentum thickness for the compressible turbulent boundary layer with and without heat transfer gives good agreement with experimental data. For practical purposes a knowledge of the shape parameter, displacement thickness and boundary-layer thickness are also often required. In this note it is shown that the predictions of these additional boundary-layer parameters by extending the work of Spalding and Chi do not compare so favourably with experiment. New correlations have therefore been developed and are reported in this note which provides the basis of Item No. 68020 in the Royal Aeronautical Society Aerodynamics Sub- Series of Data Items.
A Circulation Meter
Authors: Flower J. W.
Published: July 2022

Many of the flow patterns associated with experiments in fluid mechanics include vortices, or vortex sheets, and frequently knowledge as to the position and strength of these vortices is desirable. Wool tufts and spinners are useful in determining vortex position, but can give no indication of the vortex strength or circulation. Yawmeters cannot readily give vortex position, although (with a fair amount of labour) the circulation can be determined.
Effects of Rotation on a Turbulent Jet Flow over a Cylinder
Authors: Keil H. , Sridhar K.
Published: July 2022

In all of the experimental and theoretical work done on wall jets(1-3), the flow always passed over a stationary surface. An exception to this is the theoretical analysis reported in ref. 4 in which a laminar axi-symmetric jet impinged on a rotating disc.

The present investigation aims to provide information on the flow of a turbulent jet over a rotating cylinder. The curvature of the wall, the jet slot width and the initial speed of the jet are kept constant. The speed of rotation is the important variable.
The Influence of Operational and Technical Factors on Air Transport Regulation
Authors: Wheatcroft Stephen
Published: July 2022

When we talk about the system of air transport regulation we normally refer to the processes by which governments exercise authority over the licensing of airlines to routes and control the fares and rates which are charged on those routes. Sometimes the concept of air transport regulation is extended to embrace the controls which governments exercise over the technical standards of airline operations, and thus include the licensing of personnel and the certification of airworthiness standards. In this lecture I propose to use the term “air transport regulatory system” in a much broader sense. I want the term to be interpreted as meaning the total system by which all relevant aspects of public policy are brought to bear upon airline operations and the ways in which they influence the air services which are available to the travelling public. Under this definition of air transport regulation I shall, for example, include governmental interests in promoting a high rate of technological progress in aeronautics as part of the overall system.
The Independent Airlines
Authors: Bristow A. E.
Published: July 2022

I was glad to be asked to talk to the Graduates’ and Students’ Section of the Society because, in the years to come, it is you who will be carrying some of the responsibility for developing the air transport industry of this country to extents which will make today's efforts appear puny. In an industry which is doubling in size every five years—a fourfold increase during the next decade—it is important that we get the structure right. There is a chance to do this now, while the whole future of British commercial aviation is under review that may not, indeed should not, occur again for many years. Change inevitably brings disruption and upheaval but some re-organisation and re-orientation is essential if the industry is to have an expansive but reasonably stable future bringing greater efficiency, higher profitability and enhanced benefits to the national economy. The recent White Paper Civil Aviation Policy holds out little prospect that, under a Socialist Government, these aims will be fully realised in the Seventies.
The High Speed Track Facility and its Comparison with other Full Scale Testing Techniques
Authors: Howe D.
Published: July 2022

In the fourteenth Henson and Stringfellow lecture delivered to the Society earlier this year, Speechley compared the development of the helicopter with that of conventional fixed-wing aircraft. He pointed out that some ten years elapsed between Kittyhawk and the mass production of military aircraft which occurred during the First World War, and that there were a further two decades before the commercial breakthrough of the DC2/3 aircraft. Initial helicopter progress followed a similar pattern but the commercial breakthrough is still awaited more than twenty years after the beginning of large-scale military procurement.
Non-Linear Response of a Simply-Supported Non-Homogeneous Beam
Authors: Bauer H. F.
Published: July 2022

The advent of air- and spaceflight vehicles and that of nuclear explosions as well as the trend of constantly increasing and higher structures have brought attention to the need for better understanding of the dynamic response of such a system. The knowledge of free and forced large amplitude vibrations of structures or parts of it, as well as the response of them to pulse excitations, are of pronounced influence upon their design. Whether one deals with aerospace structures or civil structures, such as bridges or buildings, one is faced with the prediction of loads due to some wind or gusts.
Maximum Lift on Slender Wings
Authors: Bridson D. W. , Hancock G. J.
Published: July 2022

Many authors have established that a finite wing in inviscid flow has a theoretical maximum lift coefficient. One formula based on a theoretical model of a rolled-up vortex system aft of an elliptically loaded wing is

where AR is the aspect ratio. Ref. 6 criticises the validity of eqn. (1) but at least eqn. (1) gives the order of magnitude of an inviscid CLmax.
Vibration Analysis Formulations for Optimisation
Authors: Bampton M. C. C.
Published: July 2022

In most dynamic analyses, it is customary to use a coarser mass idealisation than structural idealisation especially if stresses are to be involved. Compatibility between the stiffness matrix and the smaller mass matrix M is achieved by reduction of the stiffness matrix. Guyan has shown that the reduction is equivalent to a transformation of the original matrix K :

where KR is the reduced stiffness matrix and T is the transformation matrix which contains stiffness terms.
Review of Bölkow Activities in the Rotorcraft Field
Authors: Pfleiderer Kurt
Published: July 2022

A survey of the Messerschmitt-Bolkow-Blohm company's activities in the helicopter field amounts to a review of the past 15 years. The scope of these activities, as measured by their technical diversity, can only be appreciated in full if something is known of the progressive thinking involved, the company's courage in taking commercial risks and the development and contract situation in post-war Germany.

The Bolkow company evolved from a small engineering office into an aeronautical company in 1955, and from this time on the development of rotary wing systems was one of its important development aims.
Instruments and Electronics in Aviation
Authors: De Ferranti Sebastian
Published: July 2022

For aviation to become commercially usable and reliable, in addition to the development of aerodynamics, of reliable structures and reliable engines, there had to be the development of instruments, communications, and navigational aids. Suppose, for example, that today one could not fly through cloud, or at night, then nothing remotely resembling a regular service would be possible. Flying would still be a sport.

To illustrate what I mean I shall quote the example of another innovation with quite different properties in this respect. The first railway was immediately commercial and usable without any aids. It can be seen at once that the train running along rails is constrained compared with aircraft. It is obvious that the navigation problem here is very simple, and that there is not really a problem of control or stability—the first railway trains did not even have brakes. The mechanical skill of operating and maintaining the new device had to be learned; but very little else.
The Terminal Forces Acting on a Light Trailing Wire
Authors: Payne P. R.
Published: July 2022

A “light wire” is one for which the integrated wire weight and tangential fluid friction forces are much smaller than the weight of the load which it supports, so that only the aerodynamic force acting normal to the wire need be considered. The equations for this simplified model were first formulated by Glauert, and have been further studied by Bryant et al and Neumark, among others. Ref. 4 contains a comprehensive list of references.

In this note Glauert's equations are used to obtain numerical results for the wire shape, a wire shape integral which is of interest for trailing wire antennas, and the steady state aerodynamic forces which act upon the aircraft. Computer solutions taking cable weight into account have indicated that the results for a weightless cable are realistic for many cases.
Portrait of a Pioneer
Authors: Crocombe F. F.
Published: July 2022

John Dudley North must be almost the last of the select group of aircraft enthusiasts who started practical aviation in this country in the early years of the century. He was certainly the last to be actively concerned with the day-today activities of his company up to the day of his death, only outlived by Sir Thomas Sopwith and Oswald Short. “To become a pioneer in a youthful spirit of adventure is one thing. To use pioneering shrewdly and deliberately as a business policy is quite another. John North was able to do both.” So wrote Walter Gaunt in a special article published in January 1955 in the periodical Business.How this was achieved is some measure of my present task.
Rapier
Authors: Dunn S. C.
Published: July 2022

Rapier is a very important element in our armoury of defence against attack from the air. At low to medium altitudes the attack comes from all-weather, contour-following, very fast and very expensive aircraft, through much more numerous and diverse conventional aircraft limited to fair-weather operation, to helicopters and reconnaissance drones.

The perfection of radar makes the high open sky a dangerous place to be. Aircraft are best used, like any other weapon, when they enjoy the greatest advantage. They will therefore, fly high enough to see their objective (stationary or slow-moving targets) but low enough to gain concealment from radar surveillance.
The Helicopter Rotor
Authors: Jones J. P.
Published: July 2022

To be asked to give the Lanchester Lecture, on the topic of helicopters, is a great honour and just now a wonderful chance. We all know of Lanchester's basic contributions to our knowledge of the way in which lift is generated by the creation of a vortex system. For fixed wings the flow patterns are now known and the theories are in the third stage of refinement. But on helicopters, although it has been the topic of intensive research for fifteen years or more, the subject is much farther back. The results obtained are fascinating technically and pictorially and I would cheerfully discuss them for hours. But our understanding is far from complete and I have regretfully decided to throw away a wonderful chance and leave the topic to a less formal occasion.
The Lift of a Slender Combination of a Fuselage of Rectangular Cross-Section with a High Wing
Authors: Andrews R. D.
Published: July 2022

In a recent paper, Portnoy discussed the properties of a slender-wing with a slender half-body of revolution mounted beneath it. Another configuration of the same type has a fuselage of rectangular cross-section underneath the wing. The present note gives results for the lift on this class of configurations in attached flow and compares it with that for other wing-body combinations.

Ward's slender-body theory describes the flows about appropriately slender configurations where viscous effects are negligible (i.e. the boundary-layer thickness is small in comparison with the transverse dimensions of the body and no separation occurs upstream of the station under consideration). A restriction of the simplified version used in this note is that no element of a load-bearing surface may be upstream of that station. This implies that the wing span must not decrease in a spanwise direction. Another assumption we make is that no leading-edge separation occurs.
Behaviour of the Vortex Sheet at the Trailing Edge of a Lifting Wing
Authors: Mangler K. W. , Smith J. H. B.
Published: July 2022

The calculation of the inviscid, incompressible flow past non-lifting three-dimensional bodies has been greatly facilitated by A. M. O. Smith and his collaborators, using distributions of elementary singularities over the surface of the body. There is considerable current interest in the extension of this work to lifting bodies, involving the representation of the real viscous wake by a vortex sheet of zero thickness in the inviscid model of the flow. In view of this interest, it is appropriate to consider the way in which such a vortex sheet behaves at the trailing edge of a wing with non-zero trailing-edge angle. Is the sheet tangential to the upper surface of the wing, to the lower surface, or to neither?
Shock-Induced Laminar Boundary-Layers
Authors: Ackroyd J. A. D.
Published: July 2022

The note is concerned with four points in the analysis of laminar shock-induced boundary-layers in undissociated gases. The first point concerns the restrictions imposed by the requirement that similar solutions be obtained. The second point concerns the properties of two simple solutions which can be obtained when the Prandtl number is unity. The third point concerns the accurate prediction of surface heat transfer rate in terms of surface shear stress. Here, an extension and correction to a method employed by Spence is presented. The fourth point concerns the accurate prediction of surface shear stress, a slight modification to an existing mean enthalpy method being suggested in an attempt to correlate most of the available data.
Reinforced Circular Holes in Cylindrical Shells. Stress Concentrations Due to Internal Pressure
Authors: Rao K. P. , Davies G. A. O.
Published: July 2022

In Part I the analysis was given of a circular hole (radius a) reinforced by a compact ring symmetrically placed either side of the shell skin which was assumed to be attached to the ring at its shear centre and centroid. The shell radius/thickness ratio (R/t) was assumed not to be large enough for non-linear effects to be significant.
Management of Design
Authors: Turner B. T.
Published: July 2022

An informal discussion meeting of the Management Studies Group of the Society took
place on 1st April, 1969. Mr. Barry Turner opened the discussion, and has
summarised the proceedings.

Design management is concerned with the exercise of mental, verbal and graphical skills which are so directed and controlled to meet a social need or needs. Any manager's job can briefly be stated as being composed of two complementary parts:

(i) Deciding what has to be done, and

(ii) assuring that the appropriate actions are taken to achieve the decisions taken.

The functions of a manager are concerned with; forecasting, planning, organising, controlling, evaluating and directing. In practice these tend to spiral around as time proceeds, and may be depicted as in Fig. 1. In the centre of this diagram is the important factor of motivation which all good managers have and are able to inject into their staff. In engineering, design is the necessary prelude to the manipulation of matter. But before design ideas can be turned into hardware they have to be transferred through the design process.
Management and Marketing in Large Enterprises
Authors: Brooks Peter W.
Published: July 2022

This paper looks at several typical management and marketing aspects of the operations and organisation of a large British engineering company whose biggest market is abroad. Exporting into highly competitive international markets is, therefore, a dominant feature of its business. Although this company is involved in a specialised field of advanced technology—that of aircraft manufacture—it happens also to be one with many of the characteristics of both the capital goods and consumer goods industries. It is, therefore, probably not unrepresentative, in many respects, of large industrial enterprises as a whole which are operating internationally.
The Evolution of the US Tactical Missile Programme
Authors: Augustine N. R. , Yates R. M.
Published: July 2022

Certainly one of the most important elements in today's spectrum of military weaponry is the tactical guided missile. Few developments have offered a greater opportunity to increase the fighting potential of our military forces. As it happens, however, few developments have caused the frustrations and problems along their path to fruition that have been associated with the tactical guided missile.

In selecting armament for a particular role, the merits and demerits of each class of weapon must be considered to arrive at that which is best for the particular application, and as such the guided missile must be viewed as just one of the possible candidates to be evaluated in its turn. The guided weapon often wins, of course, for it has certain unique characteristics that give it a number of advantages. But it is common now to find that in some applications that a decade ago would have been conceded to the missile, that guns and other types of “conventional” ordnance may be better.
Calculation of the Flow Field Downstream of the Fan Nozzle of a Turbofan Aero Engine
Authors: Street P. G.
Published: July 2022

The pursuit of better economics for subsonic transport aircraft has led in recent years to the development of high by-pass ratio turbofan aero engines. The improved efficiency of these engines results mainly from an improvement in the propulsive, or Froude efficiency brought about by the use of an increased airflow with a smaller jet velocity for a given thrust level. The specific thrust (thrust per unit airflow) for a high by-pass ratio engine is thus appreciably lower than for a conventional turbojet so that the ratio of engine gross thrust to installed net thrust is higher. Typically, for an engine of unit by-pass ratio, the ratio of gross to net thrust is about 1·6 under cruise conditions, while for an engine of by-pass ratio five it is between 2·6 and 3. Losses in the exhaust system effectively act on the gross thrust level so that any inefficiency is magnified by the gross to net thrust ratio. Thus the high values of this ratio in the new high by-pass engines render losses in the exhaust system of especial significance.
Some Objectives and Problems Associated with Model Testing
Authors: Simons I. A.
Published: July 2022

The need for the testing of aircraft is of course very obvious. New types of aircraft must be flight tested to check the performance predictions, define operational flight envelopes, or set safe-life limits for various components etc. Other flight tests are directed towards the investigation of particular problems, but much of this type of study is best done by model tests; especially when information is required in those areas where theories are known to be poor or even non-existent.
The Use of a Runway Vehicle for Testing Lifting Rotors in Simulated Forward Flight
Authors: Smith M. C. G.
Published: July 2022

During recent years a major research programme has been undertaken at the National Gas Turbine Establishment into the subject of circulation control and its application to lifting rotors. In the case of rotors intended to be used on helicopters and stowed rotor aircraft, a very important part of the research work is the examination of rotor behaviour in forward flight. Traditionally, this has been investigated mainly on full-scale aircraft but more recently model scale experiments have been done in wind tunnels, particularly in the USA where there are a number of suitably large tunnels.
The Role of Flight Recording in Aircraft Accident Investigation and Accident Prevention
Authors: Feltham R. G.
Published: July 2022

This paper is intended to provide a summary of the present role of the flight recorder in relation to the investigation of aircraft accidents and to refer briefly to its future role in this field, together with its potential for flight safety monitoring.

The paper deals principally with the philosophy of data recording for these purposes and with the general needs of the associated data recording, recovery and analysis systems. It also describes the predominant problems encountered up to the present time in the use of such systems for accident investigation purposes in the United Kingdom. The technical problems relating to system design, information recovery and analysis are, however, of a specialised nature and can only be referred to in brief terms within the scope of this paper.
An Improved Blade Root Design for Axial Flow Compressors (and Turbines)
Authors: Shaw H.
Published: July 2022

To save weight, designers of aircraft gas turbines aim to produce axial compressors with fewer rows of blades and greater mass flows per unit of frontal area. These improvements often consist of increases in blade tip speeds and reductions in the ratio of the hub to tip diameters. As the efficiency of transonic blading is partly dependent upon a low value of blade pitch/chord it is now frequently necessary to design a blade with a greater actual chord at the tip than at the hub.
Value Engineering — A Challenge to Management
Authors: Crum L. W.
Published: July 2022

“I believe that everything made in England is costing too much for export. Everybody must do more and better work if we are to keep our present standard of life, or they must make better use of less money”.

Sir Henry Royce 1931

Students of history or economics would not be in any way surprised to read this quotation, declaring it to be nothing more than a visionary's warning and the often characteristic habit of history repeating itself, since the words seem more fitting to the problems facing the country today than in the grim early 1930s when the whole world was suffering from a serious trade recession. Although increased efficiency, on the lines suggested by Sir Henry, would no doubt have alleviated this country's problems, it is most doubtful whether under such adverse world conditions it would have been sufficient by itself.
Project Economic Evaluation
Authors: Norman P. A.
Published: July 2022

The early papers given in this symposium, dealing with Civil and Military Market Research, form the basis for identification of possible new projects. The last paper to be given today, dealing with Value Analysis, deals with the subject of meeting design, manufacturing and quality requirements for a given cost.

The object of this paper is to deal with one important aspect of the process that takes place between completion of recommendations from Market Research and the setting up and control process in Value Analysis. To give some idea of the activities that take place between phases involving Market Research and Value Analysis, the flow chart of Fig. 1 has been prepared showing the interrelation between technical, manufacturing and economic appraisals.
2020 vision: the prospects for large civil aircraft propulsion
Authors: Birch N. T.
Published: July 2022

This paper will examine the prospects for propulsion systems for large civil transport aircraft over the next two decades, to the year 2020. This period is likely to see the market drivers for future propulsion system development change from the more traditional ones of fuel consumption and weight, to also include those that affect the impact of civil aviation on the environment, and the continuing pressure to reduce the cost of ownership of civil engines, namely, product unit cost, maintenance costs and reliability. Fifty years of civil aero-engine development are reviewed and trends showing the likely limits to the main engine performance parameters are provided. The paper concludes with consideration of a number of new civil aircraft and engine concepts that may emerge in the next 20 years
Use of bifurcation diagrams in piloted test procedures
Authors: Lowenberg M. H. , Y. Patel
Published: July 2022

This paper investigates the potential benefits of utilising bifurcation analysis results in the planning and evaluation of piloted simulator trials of manoeuvrable aircraft, particularly when encountering nonlinear phenomena such as departure. Comparisons of bifurcation diagram predictions with piloted simulations are performed in order to validate the technique for application to realistic flight conditions. A close relationship is found between the theoretical and the experimental responses, and potential improvements in effectiveness of piloted test programmes are identified. Proposals for enhancing the predictive capability of bifurcation methods are made.
The accuracy of flat plate, turbulent skin friction at supersonic speeds
Authors: Squire L. C.
Published: July 2022

This paper presents a comparison of turbulent skin-friction coefficients measured by floating element balances in zero pressure gradient conditions for a wide range of Mach numbers and Reynolds numbers. From these comparisons it is clear that although a large number of measurements have been made it is impossible to use these measurements to find the skin-friction coefficient for a given Mach number and Reynolds number to an accuracy of better than ±2 to 3%. This estimate of accuracy applies only to the range of Mach numbers and Reynolds within which there are a reasonable number of measurements to compare. Outside this range, say for Reynolds numbers based on momentum thickness greater than 40,000 and Mach numbers greater than 2 the uncertainty is greater.
The meaning of life
Authors: Bristow J. W.
Published: July 2022

'Life extension’ is the theme of this paper. However, unless there is a clear understanding of what ‘life’ means it is not readily obvious as to the appropriate means to adopt for its ‘extension'. This paper will explore some of the background to the meaning of life and the means being adopted to extend it for fixed wing civil transport aircraft. The focus will be on the safety of airframe structures from a regulatory viewpoint.

A comparative review is made of the evolution, on both sides of the Atlantic, of civil aviation requirements for the fatigue, failsafe and damage tolerance design of structures. Definitions of life are discussed in the context of recent developments of ageing aircraft structural programmes. These definitions are accompanied by an extensive reference list.

Example results are presented from a recent research study which compares the performance of a number of fracture mechanics analysis methods with conventional fatigue endurance approaches to the prediction of lives. The work was carried in a way directly representative of the current aircraft design environment. It was undertaken by three separate aircraft manufacturers and applied to a range of aircraft structural features that were not necessarily originally designed to damage tolerant principles.
Two dimensional direct numerical simulation of nonreacting confined supersonic mixing layer
Authors: Chakraborty D. , Mukunda H. S. , Paul P. J.
Published: July 2022

Direct Numerical Simulation (DNS) results are presented for high speed nonreacting mixing layer in a confined test section. The hyper-velocity mixing layer experiment of Erdos et al with H2/N2 stream is simulated by discretizing two dimensional Navier Stokes equation using a higher order (fourth order spatial and second order temporal) compact numerical algorithm. A favourable comparison of the computation with experimentally measured wall static pressure forms the basis of further analysis. Instantaneous flow picture and the mean profiles of various flow variables were examined to determine the development and general characteristics of the confined mixing layer. It has been found that the growth of the mixing layer is towards the high speed side of the layer. Various turbulence quantities were derived from the stored time series data of the DNS calculation and the results were compared with the experimental results of supersonic free shear layer as no experimental results of turbulence statistics are available for the confined hypervelocity mixing layer. The increasing Reynolds stress data with the flow direction indicate that the turbulence is sustained by transferring the energy from the mean flow to the fluctuating field as the shear layer develops. Although the Reynolds stress is negligible in the most portion of the wall boundary layers, effect of counter gradient effect is observed in the far downstream location of the lower wall boundary layer. The general conclusion that for the supersonic mixing layer, various turbulence quantities like Reynolds stress, turbulence intensities (both streamwise and transverse) decrease with the increase in the convective Mach number is also confirmed by our results.
Civil aviation noise – reduction with economic reality
Authors: Bradley A. J.
Published: July 2022

Aircraft noise disturbs a significant number of people who live close to airports. It is tolerated due to the economic and social benefits those aircraft bring to society as a whole. However, the levels that are tolerated from individual aircraft must reduce, to compensate for increases in numbers of aircraft movements and the desire for an ever-improving environment for all of society's members. The issue is how to achieve that reduction without destroying social and economic benefits of air travel.
Prediction of scale effects at transonic speeds: current practice and a gaze into the future
Authors: Haines A. B.
Published: July 2022

The paper reviews present practices in the prediction of scale effect at transonic speeds and considers how these may have to change in the future in the light of possible changes in wing design standards. Particular issues highlighted in the paper include the research that is needed to obtain the potential benefits that should come from the ability to test models at near-full-scale Reynolds numbers in cryogenic tunnels such as the ETW and second, the different experimental techniques that may have to be introduced if aerodynamic designers attempt to realise their long-held ambition of obtaining extensive laminar flow in flight.
Active inlet flow control technology demonstration
Authors: Hamstra J. W. , Miller D. N. , Truax P. P. , Anderson B. A. , Wendt B. J.
Published: July 2022

This paper presents results from a joint Lockheed Martin/NASA Glenn effort to design and verify an ultra-compact, highly-survivable engine inlet subsonic duct based on the emerging technology of active inlet flow control (AIFC). In the AIFC concept, micro-scale actuation (∼mm in size) is used in an approach denoted ‘secondary flow control’ to intelligently alter a serpentine duct's inherent secondary flow characteristics with the goal of simultaneously improving the critical system-level performance metrics of total pressure recovery, spatial distortion, and RMS turbulence. In this approach, separation control is a secondary benefit, not a design requirement. The baseline concept for this study was a 4:1 aspect ratio ultra-compact (LID= 2·5) serpentine duct that fully obscured line-of-sight view of the engine face. At relevant flow conditions, this type of duct exhibits excessive pressure loss and distortion because of extreme wall curvature. Two sets of flow control effectors were designed with the intent of establishing high performance levels to the baseline duct. The first set used two arrays of 36 co-rotating microvane vortex generators (VGs); the second set used two arrays of 36 micro air-jet (microjet) VGs, which were designed to produce the same ‘vorticity signature’ as the microvanes. Optimisation of the microvane array was accomplished using a design of experiments (DOE) methodology to guide selection of parameters used in multiple Computational Fluid Dynamics (CFD) flow solutions. A verification test conducted in the NASA Glenn W1B test facility indicated low pressure recovery and high distortion for the baseline duct without flow control. With microvane flow control, at a throat Mach number of 0·60, pressure recovery was increased 5%, and both spatial distortion and turbulence were decreased approximately 50%. Microjet effectors also provided significantly improved performance over the baseline configuration.
The NASA tetrahedral unstructured software system (TetrUSS)
Authors: Frink N. T. , Pirzadeh S. Z. , Parikh P. C. , Pandya M. J. , Bhat M. K.
Published: July 2022

The NASA tetrahedral unstructured software system (TetrUSS) was developed during the 1990s to provide a rapid aerodynamic analysis and design capability to applied aerodynamicists. The system comprises of loosely integrated, user-friendly software that enables the application of advanced Euler and Navier-Stokes tetrahedral finite volume technology to complex aerodynamic problems. TetrUSS has matured well because of the generous feedback from many willing users representing a broad cross-section of background and skill levels. This paper presents an overview of the current capabilities of the TetrUSS system along with some representative results from selected applications.
On the aerodynamic characteristics of thin slab delta wings at hypersonic speeds - part 2: effect of wing geometry
Authors: Ramesh R. , Vasudevan B. , Ramaswamy M. A. , A. Prabhu
Published: July 2022

We report our findings on the aerodynamic characteristics of thin slab delta wings at hypersonic speeds. We have tested wings with three sweeps (76°,70° and 65°) and four t/c ratios (0·04, 0·053, 0·066 and 0·10) using a special thin three-component balance. To date, the wing with tic of 0·040 is the thinnest wing ever tested without lee-side body at any hypersonic Mach number. The study was carried out at Mach number of 8·2, Reynolds number of 2·13 x 106 and incidence of -4° to 12°. In general, for any given t/c ratio, the increase in sweep decreased the CN whereas increased CM and CA. A possible explanation, for the effect of sweep, is given using the pressure data available in the literature. We also observed that for the sweeps considered, the t/c does not have any effect on CN and CL but increasing t/c increased CM and CA, reduced (L/D)max and moved the Xcp upstream. Blunt slab delta wings are shown to possess a unique property, wherein the CD increases with increase in sweep at higher sweep angles. This property also reflects in the (L/D) characteristics. Furthermore, the slab delta wings does not exhibit the classical CLα behaviour of sharp delta wings given in the literature. An empirical correlation has been developed to correlate CAo over a wide range of Mach number, t/c and sweep. Linearised theory has been shown to be useful in predicting the (L/D)max at Mach numbers as high as 20, for a wide range of t/c and sweep back angle.
UK Air Service Development
Authors: Brilliant H. C.
Published: July 2022

It seems to me that the report contains 3 salient points in reference to domestic air services. These are:

1.

The unprofitability of domestic services generally.

2.

Competition on the trunk routes may have been beneficial to the customer in the short term but it may also have led to higher fares. (This need not however be true of the long term.)

3.

The absence of any coherent proposals for exploiting VTOL/STOL development in expanding domestic air services.
Cumulative Damage Problems in Aircraft Structures and Materials
Authors: Schijve J.
Published: July 2022

Fatigue in aircraft structures is a problem for which quantitative and generally accepted solutions are not available as yet. Even in recent years significant fatigue failures in aircraft structures have occurred. Some of these failures can be attributed to either poor design or underestimating of the fatigue environment. Unfortunately such statements are of little help since there are a confusingly large number of aspects involved. For a designer considering fatigue problems, experience, qualitative understanding and a good intuition are therefore essential.
Impacts of eucalyptus biochar application on greenhouse gas emission from an upland rice–sugarcane cropping system on sandy soil
Authors: Butphu Sucharat , Kaewpradit Wanwipa
Published: July 2022

An on-farm field experiment was conducted in northeastern Thailand to assess the effects of different eucalyptus biochar (BC) application rates, in combination with mineral fertilizers, on upland rice and a succeeding crop of sugarcane on sandy soil. Soil mineral N and greenhouse gas emissions were also evaluated. The field experiment consisted of three treatments: no biochar (BC0), 3.1 Mg ha−1 of biochar (BC1), and 6.2 Mg ha−1 of biochar (BC2). All treatments received the same recommended fertilizer rate. Soil mineral N, and emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored after BC application. The results revealed that the BC2 treatment caused lower soil mineral N content than that of the BC0 treatment during the upland rice period. During the sugarcane period, the BC2 treatment induced a greater soil mineral N content than the BC1 treatment but had no significant difference from the BC0 treatment. The BC2 treatment resulted in significantly lower cumulative CH4 and N2O emissions than the BC0 treatment during the upland rice period. In conclusion, we found that the BC2 treatment alleviated the global warming potential from CH4 and N2O emissions throughout the experiment, causing slight changes in soil N availability in the upland rice–sugarcane cropping system.
Comparison of two coprological methods for the diagnosis of Eurytrema ssp. in cattle and sheep
Authors: Olmos L.H. , Pantiu A. , Avellaneda-Cáceres A. , Valencia P.N. , Cayo P.N. , Signorini M. , Micheloud J.F.
Published: July 2022

Eurytrematosis is a disease caused by flukes of the genus Eurytrema. These parasites infect the pancreatic ducts of a wide variety of species, including cattle, sheep and humans. Diagnosing eurytrematosis through the analysis of faecal samples can be difficult because most of the available techniques are considered of low sensitivity. In this context, a modification of the Dennis, Stone and Swanson technique (Belem Sedimentation Technique, BST) was previously developed to increase the probability of detecting infected animals; nevertheless, the values of eggs per gram obtained using the modified technique are generally low. We proposed a modification of the this technique (MBST), to increase the sensitivity and detection rate of infected animals. The objective of this work was to describe MBST and compare it with BST. Faecal samples of 212 clinically healthy animals (174 from cattle and 38 from sheep) from 20 farms were taken by the intra-rectal route and stored at 4°C. The samples were processed using BST and MBST. Positive samples amounted to 55 (25.9%) using BST and 121 (57.1%) using MBST. In the simples from cattle, 52 (29.8%) and 107 (61.4%) were positive in BST and MBST, respectively. In sheep, three (7.8%) and 14 (36.8%) positive samples were obtained in BST and MBST, respectively.The results obtained using the two methods were significantly different, indicating a lack of agreement between their findings. The results suggest that MBST is a more sensitive method to detect Eurytrema spp. eggs in faeces than BST.
Morphological and molecular characterization of larval trematodes infecting the assassin snail genusAnentomein Thailand
Authors: Chomchoei N. , Backeljau T. , Segers B. , Wongsawad C. , Butboonchoo P. , Nantarat N.
Published: July 2022

The assassin snail genusAnentomeis widespread in Southeast Asia, and is distributed all over the world via the aquarium trade. One species of genusAnentome,Anentome helena, is known to act as intermediate host of parasitic trematodes. This study investigates the taxonomic diversity of larval trematodes infectingA.helenaandAnentome wykoffiin Thailand. Larval trematodes were identified by combining morphological and DNA sequence data (cytochromecoxidase I and internal transcribed spacer 2). Species delimitation methods were used to explore larval trematode species boundaries. A total of 1107 specimens ofAnentomesp. were collected from 25 localities in Thailand. Sixty-two specimens ofA.helena(n= 33) andA.wykoffi(n= 29) were infected by zoogonid cercariae, heterophyid metacercariae and echinostome metacercariae, with an overall prevalence of 5.6% (62/1107) and population-level prevalences in the range of 0.0–22.3%. DNA sequence data confirmed that the larval trematodes belong to the families Echinostomatidae, Heterophyidae and Zoogonidae. As such, this is the first report of zoogonid cercariae and heterophyid metacercariae inA.helena, and echinostome metacercariae inA.wykoffi. Moreover, this study provides evidence of tentative species-level differentiation between ThaiEchinostomasp. and CambodianEchinostoma mekongi, as well as withinEchinostoma caproni,Echinostoma trivolvisandEchinostoma revolutum.
Is Practical Deliberation Bound by a Coherency Requirement? Foundational Normative States, Volitional Conflict, and Autonomy
Authors: van Gils-Schmidt Henk Jasper
Published: July 2022

Harry G. Frankfurt has put the problem of volitional conflict at the center of philosophical attention. If you care fundamentally about your career and your family, but these cares conflict, this conflict undermines the coherency of your decision standard and thereby your ability to choose and act autonomously. The standard response to this problem is to argue that you can overcome volitional conflict by unifying your foundational motivational states. As Frankfurt puts it, the ‘totality of things that an agent cares about’ plus his ‘ordering of how important to him they are effectively specifies his answer to the question of how to live’ (The Reasons of Love(Princeton: Princeton University Press, 2004), p. 23). In this paper, I critically assess the three main reasons given for such a coherency requirement: 1) we can do only one action at a time; 2) our motivational states come with normative pressure towards coherency; and 3) conflicting motivational states provide us with an incoherent decision-making framework. I conclude that these reasons do not ground a coherency requirement for practical deliberation and argue that we can autonomously express ourselves as volitionally conflicted by acting on our conflicting motivational states over the course of multiple actions.
Hegel on spirited animals
Authors: Schuringa Christoph
Published: July 2022

Hegel conceives of human beings as both natural and spirited. On Robert Pippin's influential reading, we are natural by being ‘ontologically’ like other animals, but spirited through a ‘social-historical achievement’. I contest both the coherence of this reading and its fidelity to Hegel's texts. For Hegel the human being is the truth of the animal. This means that spirit's self-production is not, as Pippin claims, an achievement that an animal confers on itself, but the realization of what the human being is. I end by specifying Aristotelian features of Hegel's account whose neglect by Pippin can help explain what goes wrong in his reading, and provide the outlines of a reading that is both coherent and faithful to Hegel's texts.
Design change prediction based on social media sentiment analysis
Authors: Koh Edwin C.Y.
Published: July 2022

The use of artificial intelligence (AI) techniques to uncover customer sentiment is not uncommon. However, the integration of sentiment analysis with research in design change prediction remains an untapped potential. This paper presents a method that uses social media sentiment analysis to identify opportunities for design change and the set of product components affected by the change. The method builds on natural language processing to determine change candidates from textual data and uses dependency modeling to reveal direct and indirect change propagation paths arising from the change candidates. The method was applied in a case example where 3665YouTubecomments on a diesel engine were analyzed. Based on the results, two engine components were recommended for design change with six others predicted as likely to be affected through change propagation. The findings suggest that the method can be used to aid decision quality in product planning through a better understanding of the change impact associated with the opportunities identified.
COVID vaccine-associated myocarditis in an 8-year-old patient
Authors: Mehta Karina , Cohen Richard , Kelly Brendan , Grosse-Wortmann Lars
Published: July 2022

COVID vaccine-associated myocarditis was first identified in March 2021. There have been numerous case reports that detail the clinical course of paediatric patients older than age 12 with COVID vaccine-associated myocarditis. There are still very few reports of children between the ages of 5 and 11 with COVID vaccine-associated myocarditis. We present an 8 year- old with COVID vaccine-associated myocarditis after his second vaccination against SARS-CoV-2.