bluuebunny/crossref_metadata_2025 huggingface dataset:
The Netherlands Heart Tissue Bank
Authors: Henkens M. T. H. M. , van Ast J. F. , te Riele A. S. J. M. , Houweling A. C. , Amin A. S. , Nijveldt R. , Antoni M. L. , Li X. , Wehrens S. M. T. , von der Thüsen J. H. , Damman K. , ter Horst E. N. , Manintveld O. C. , Abma-Schouten R. Y. , Niessen H. W. M. , Silljé H. H. W. , Jukema J. W. , Doevendans P. A.
Published: July 2022

Aim

Cardiac diseases remain a leading cause of cardiovascular disease (CVD) related hospitalisation and mortality. That is why research to improve our understanding of pathophysiological processes underlying cardiac diseases is of great importance. There is a strong need for healthy and diseased human cardiac tissue and related clinical data to accomplish this, since currently used animal and in vitro disease models do not fully grasp the pathophysiological processes observed in humans. This design paper describes the initiative of the Netherlands Heart Tissue Bank (NHTB) that aims to boost CVD-related research by providing an open-access biobank.

Methods

The NHTB, founded in June 2020, is a non-profit biobank that collects and stores biomaterial (including but not limited to myocardial tissue and blood samples) and clinical data of individuals with and without previously known cardiac diseases. All individuals aged ≥ 18 years living in the Netherlands are eligible for inclusion as a potential future donor. The stored samples and clinical data will be available upon request for cardiovascular researchers.

Conclusion

To improve the availability of cardiac tissue for cardiovascular research, the NHTB will include extensive (cardiac) biosamples, medical images, and clinical data of donors with and without a previously known cardiac disease. As such, the NHTB will function as a translational bridge to boost a wide range of cardiac disease-related fundamental and translational studies.
Online-Befragung der Ärzteschaft zu Kenntnissen über Berufskrankheiten
Authors: Thielmann Beatrice , Böckelmann Irina
Published: July 2022

Hintergrund

Basiswissen über Berufskrankheiten (BK) ist für jeden Arzt erforderlich. BK dürfen nicht übersehen werden. Hauptziel dieser Studie war es, das selbsteingeschätzte Wissen zum Thema arbeitsbedingte Erkrankungen (aE) und BK sowie das Handeln bei begründetem Verdacht auf eine BK bei Ärzten verschiedener Fachgebiete zu erfassen und Ärzte verschiedener Fachrichtungen in Bezug auf dieses Thema zu sensibilisieren, insbesondere für die berufsbedingten Krebserkrankungen.

Methodik

Im Zeitraum von 11/2014 bis 5/2015 erfolgte eine Online-Befragung unter Ärzten verschiedener Fachrichtungen.

Ergebnisse

Es nahmen 254 in Sachsen-Anhalt registrierte Ärzte/innen, die ihr Studium in verschiedenen Bundesländern absolviert haben, an der Befragung teil. Der größte Anteil der Ärzte/innen (69,7 %) war zwischen 40 und 59 Jahre alt. Der überwiegende Teil der Ärzteschaft verfügte über 16 bis 30 Berufsjahre. Knapp ein Viertel aller Befragten schätzte den eigenen Kenntnisstand zu diesem Thema als mangelhaft/ungenügend ein. Die Hälfte der Befragten gab eine nicht ausreichende Vorbereitung zu dieser Problematik, während des Studiums oder während der Facharztausbildung, in ihrem Fach an. 91,1 % der Befragten unterschätzten die Wichtigkeit der arbeitsmedizinischen Kenntnisse auf diesem Gebiet während des Studiums teilweise oder komplett. Knapp drei Viertel der Befragten haben während ihrer beruflichen Tätigkeit noch keine Fortbildungsangebote zu dieser Thematik wahrgenommen.

Diskussion

Es bestehen hohe fachliche und ethische Anforderungen an den Arzt, BK frühzeitig zu erkennen und der Anzeigepflicht bei BK nachzugehen. Die Befragung diente u. a. auch dem Ziel, die Wege der Qualitätssicherung der universitären Lehre sowie von Fort- und Weiterbildungen mit einem interdisziplinären Charakter aufzuzeigen. Gemeinsame Fortbildungen zur Vermittlung der arbeitsmedizinischen Kompetenz zum Thema Berufskrankheiten sollten vermehrt angeboten werden. Die Kommunikation in der Lehre soll aufzeigen, wie wichtig die arbeitsmedizinischen Kenntnisse für jeden Arzt sind.
Lead-Carbon Batteries toward Future Energy Storage: From Mechanism and Materials to Applications
Authors: Yin Jian , Lin Haibo , Shi Jun , Lin Zheqi , Bao Jinpeng , Wang Yue , Lin Xuliang , Qin Yanlin , Qiu Xueqing , Zhang Wenli
Published: July 2022

The lead acid battery has been a dominant device in large-scale energy storage systems since its invention in 1859. It has been the most successful commercialized aqueous electrochemical energy storage system ever since. In addition, this type of battery has witnessed the emergence and development of modern electricity-powered society. Nevertheless, lead acid batteries have technologically evolved since their invention. Over the past two decades, engineers and scientists have been exploring the applications of lead acid batteries in emerging devices such as hybrid electric vehicles and renewable energy storage; these applications necessitate operation under partial state of charge. Considerable endeavors have been devoted to the development of advanced carbon-enhanced lead acid battery (i.e., lead-carbon battery) technologies. Achievements have been made in developing advanced lead-carbon negative electrodes. Additionally, there has been significant progress in developing commercially available lead-carbon battery products. Therefore, exploring a durable, long-life, corrosion-resistive lead dioxide positive electrode is of significance. In this review, the possible design strategies for advanced maintenance-free lead-carbon batteries and new rechargeable battery configurations based on lead acid battery technology are critically reviewed. Moreover, a synopsis of the lead-carbon battery is provided from the mechanism, additive manufacturing, electrode fabrication, and full cell evaluation to practical applications.

Graphical abstract
R package DCchoice for dichotomous choice contingent valuation: a contribution to open scientific software and its impact
Authors: Aizaki Hideo , Nakatani Tomoaki , Sato Kazuo , Fogarty James
Published: July 2022

The R package DCchoice is designed to mitigate programing-related barriers to the application of dichotomous choice contingent valuation (DCCV) methods in empirical studies. Since its release in 2014, DCchoice has been updated. This paper introduces the current version of DCchoice which supports single-, one-and-one-half-, and double-bounded DCCVs, with and without a spike. Additionally, the willingness-to-pay and its confidence intervals can be calculated for a representative respondent as well as for a user-defined specific respondent using the current version. The associated web tutorial and R Commander plug-in for basic usage of DCchoice are also available. DCchoice has advanced DCCV applications in various fields.
Swelling of interlamellar GAGs/PGs as an initiation mechanism for aortic dissection: constitutive modeling and numerical simulations
Authors: Liu Xuyan , Ilseng Arne , Prot Victorien , Skallerud Bjørn H. , Holzapfel Gerhard A.
Published: July 2022

Aortic dissection is a life-threatening pathology that mainly affects the medial layer, which consists of multiple lamellar units. Glycosaminoglycans/proteoglycans (GAGs/PGs) can accumulate in the interlamellar space within the media and under certain circumstances swell considerably. Such behavior of GAGs/PGs induces high stresses in the elements connecting the elastic laminae and, in the event of tissue failure, leads to medial delamination and thus to the initiation of aortic dissection. The present study takes up the swelling polymer theory and couples the swelling behavior of GAGs/PGs with the anisotropic response of aortic tissues in order to investigate the initiation mechanism of aortic dissection. The computational simulation uses an advanced weighted constitutive model, which is combined with the global and submodel technique in the finite element software Abaqus. The numerical results show that the proposed method is able to generate failure stresses of the same order of magnitude as the failure stresses indicated in tensile tests. Stress concentrations are observed at the connection between interlamellar struts made of elastic fibers and elastic laminae. Such connections are hotspots at which dissections are expected to initiate. Therefore, this study presents the prediction of the onset of aortic dissection due to the accumulation and swelling of GAGs/PGs and provides a solid foundation for future modeling work.
Singular Terms and Ontological Seriousness
Authors: SCHIPPER ARTHUR
Published: July 2022

Linguistic ontologists and antilinguistic, ‘serious’ ontologists both accept the inference from ‘Fido is a dog’ to ‘Fido has the property of being a dog’ but disagree about its ontological consequences. In arguing that we are committed to properties on the basis of these transformations, linguistic ontologists employ a neo-Fregean meta-ontological principle, on which the function of singular terms is to refer. To reject this, serious ontologists must defend an alternative. This paper defends an alternative on which the function of singular terms is not generally to refer and on which they are generally ontologically noncommittal. This is the best way to reject linguistic, ‘easy’ arguments for the existence of properties. The account recommends neutralism about quantification (drawing on Barcan Marcus and Meinongianism), coherently bringing together two important yet uncombined meta-ontological movements. Moreover, it employs Ramseyan insights about the transformations to provide a nonreductionist, non-error-theoretic redundancy approach to explicit talk about properties.
Attitudes and Factors Associated With Intention to the Third Dose of COVID-19 Vaccine Among Adolescents: A Cross-Sectional Survey in 3 Provinces of China
Authors: Li Taishun , Qi Ruowen , Zhou Yi-Hua , Luo Yuqian , Wang Shi-Yuan , Chen Bingwei , Xu Biyun
Published: July 2022

Objective:

The COVID-19 caused a world pandemic, posing a huge threat to global health. Widespread vaccination is the most effective way to control the pandemic. Vaccination with the third dose of the COVID-19 vaccine is currently underway. We aimed to determine the attitude of adolescents toward the third dose of COVID-19 vaccine.

Methods:

A structured questionnaire was administered between 16 August and 28 October 2021 among adolescents aged 12–17 years in three provinces of eastern region of China based on convenience sampling. The questionnaire was specifically developed to assess the adolescents’ attitude toward and willingness to accept a third dose of the COVID-19 vaccine.

Results:

In total, 94.3% (1742/1847) of the adolescents intended to accept the third dose of the COVID-19 vaccine. Age between 15–17 years, no worry about vaccine safety, confidence for vaccine effectiveness, and supporting opinion from parents were independently associated with acceptance of the third dose (p < 0.05).

Conclusions:

It is necessary for governments and school administrators to raise adolescents’ and parents’ awareness of the benefits and safety of the third dose of vaccination, which should be effective to increase the vaccination coverage among adolescents.
Uniqueness and stability of equilibrium states for random non-uniformly expanding maps
Authors: BILBAO R. , RAMOS V.
Published: July 2022

We consider a robust class of random non-uniformly expanding local homeomorphisms and Hölder continuous potentials with small variation. For each element of this class we develop the thermodynamical formalism and prove the existence and uniqueness of equilibrium states among non-uniformly expanding measures. Moreover, we show that these equilibrium states and the random topological pressure vary continuously in this setting.
Stability and bifurcation of dynamic contact lines in two dimensions
Authors: Keeler J.S. , Lockerby D.A. , Kumar S. , Sprittles J.E.
Published: July 2022

The moving contact line between a fluid, liquid and solid is a ubiquitous phenomenon, and determining the maximum speed at which a liquid can wet/dewet a solid is a practically important problem. Using continuum models, previous studies have shown that the maximum speed of wetting/dewetting can be found by calculating steady solutions of the governing equations and locating the critical capillary number,$Ca_{{crit}}$, above which no steady-state solution can be found. Below$Ca_{{crit}}$, both stable and unstable steady-state solutions exist and if some appropriate measure of these solutions is plotted against$Ca$, a fold bifurcation appears where the stable and unstable branches meet. Interestingly, the significance of this bifurcation structure to the transient dynamics has yet to be explored. This article develops a computational model and uses ideas from dynamical systems theory to show the profound importance of the unstable solutions on the transient behaviour. By perturbing the stable state by the eigenmodes calculated from a linear stability analysis it is shown that the unstable branch is an ‘edge’ state that is responsible for the eventual dynamical outcomes and that the system can become transient when$Ca< Ca_{{crit}}$due to finite-amplitude perturbations. Furthermore, when$Ca>Ca_{{crit}}$, we show that the trajectories in phase space closely follow the unstable branch.
Commercial Speech and the Prohibition of Tobacco Advertising: The Colombian Constitutional Court Approach
Authors: Guzmán Silvia Serrano , Ramírez Ariadna Tovar , Cabrera Oscar A.
Published: July 2022

This article argues that the decision by the Columbian high court to totally ban the advertising and promotion of tobacco products is sound and could indeed be applied to other types of harmful products.
Chile: Front-of-Package Warning Labels and Food Marketing
Authors: Campbell Marcelo
Published: July 2022

This Article aims to show how the food industry has instrumentalized the right to freedom of expression to oppose innovative laws in Chile aimed at creating healthier food environments.
Anti-Authoritarian Learning: Prospects for Democratization in Belarus Based on a Study of Polish Solidarity
Authors: Kulakevich Tatsiana , Kubik Jan
Published: July 2022

This article examines the anti-Lukashenka protest movement in Belarus by comparing it to the Solidarity movement in Poland. We organize our analysis around the concept of four stages identifiable in the development of social movements: emergence, coalescence, bureaucratization, and decline. We argue that protests in Belarus reached the bureaucratization stage, but their transformation into a more durable movement was slowed down by the brutal repressions unleashed by the Lukashenka regime propped up by Putin’s Russia. However, the spectacular changes in people’s conceptions of national identity built around symbols different from those associated with the officialdom may sustain emotional mobilization necessary for formation of higher levels of organizations in the oppressive context of today’s Belarus. The contours of this process are brought into sharp relief when compared with the long, cumulative trajectory of the 1956-89 anti-authoritarian Polish revolts. This opens the way for cautious prognostication.
A non-traditional look at safety
Authors: Gallagher M. , Foster J. L.
Published: July 2022

During the last century, general aviation (GA), including rotorcraft, has grown from humble beginnings into a mature safe transportation system. The high levels of safety achieved in GA were made possible through the combined efforts of all members of the GA community: manufacturers, owners, operators, maintainers, academia, and regulators.
‘Smart spring’ identification for hovering rotor aeroelastic-stability augmentation
Authors: Gennaretti M. , Poloni L. , Nitzsche F.
Published: July 2022

This work deals with tailoring of adaptive material included at the roots of hingeless helicopter rotor blades to be used in individual blade control (IBC) strategies.

Usually, IBC strategies involving the use of adaptive materials either consider adaptive material embedded in the blade structure for inducing strain deformations, or apply adaptive actuators for controlling segments of the blade (e.g. for moving trailing-edge flaps).

Here, the adaptive material is used to provide augmentation of modal damping in a passive control approach, that can be conveniently tuned so as to make it the most suitable for the actual rotor configuration under examination. The presentation of a procedure for tailoring this ‘smart spring’ is the aim of the paper.

The aeroelastic blade model considered consists of a cantilever slender beam undergoing flap, lead-lag and torsional motion, coupled with a strip theory approach for the prediction of the aerodynamic loads, based on the very low frequency approximation of the pulsating-free-stream Greenberg’s theory.

Starting from this model and applying the Galërkin method, generalised mass, damping and stiffness matrices of the basic blade, as well as the incremental generalised mass, damping and stiffness matrices due to the ‘smart spring’ have been determined, the latter depending on the ‘smart spring’ inertial and elastic characteristics.

It will be shown that the application of an optimal control criterion, followed by a low frequency-approximation observer, yields the identification of the most suitable ‘smart spring’ characteristics for augmentation of rotor blade aeroelastic stability. The validity of this procedure will be demonstrated by numerical results concerning the stability analysis of two hovering blade configurations.
Low cost Mercury orbiter and sample return missions using solar sail propulsion
Authors: McInnes C. R. , Hughes G. , McDonald M.
Published: July 2022

The use of solar sail propulsion is investigated for both Mercury orbiter (MO) and Mercury sample return missions (MeSR). It will be demonstrated that solar sail propulsion can significantly reduce launch mass and enhance payload mass fractions for MO missions, while MeSR missions are enabled, again with a relatively low launch mass. Previous investigations of MeSR type missions using solar electric propulsion have identified a requirement for an Ariane V launcher to deliver a lander and sample return vehicle. The analysis presented in this paper demonstrates that, in principle, a MeSR mission can be enabled using a single Soyuz-Fregat launch vehicle, leading to significant reductions in launch mass and mission costs. Similarly, it will be demonstrated that the full payload of the ESA Bepi Colombo orbiter mission can be delivered to Mercury using a Soyuz-Fregat launch vehicle, rather than Ariane V, again leading to a reduction in mission costs.
A numerical study of hypersonic laminar film cooling
Authors: Yang X. , Badcock K. J. , Richards B. E.
Published: July 2022

A computational study has been performed to investigate the effectiveness of film cooling in hypersonic laminar flows. Both the primary and the coolant flow are air. First, three different primary flow conditions are used for validation. A uniform boundary condition at the slot exit is found to give unrealistic predictions of the heat transfer rate, whilst a boundary condition involving extended coolant inlet gives improvement. Then five coolant injection rates and three slot heights are examined. It is confirmed that increasing the coolant injection rate can increase the film cooling effectiveness for laminar cases. But slot height does not play an important role under the flow conditions in this study. The computational results are compared with the experimental results and good agreement is achieved.
Flight simulation in academia HELIFLIGHT in its first year of operation at the University of Liverpool
Authors: Padfield G. D. , White M. D.
Published: July 2022

The challenges of helicopter simulation are being tackled across a broad front as technology is developed to meet the needs of Industry. Traditionally, the strongest impetus has come from the training community and this is likely to continue for some time as simulation technology advances at increasing pace, raising fidelity standards. The development of PC-based simulation technologies is providing a significant spur in this development and lowering the cost, making complete simulation systems of reasonably high fidelity available to smaller organisations. This paper describes the first year of operation with such a system at the University of Liverpool – HELIFLIGHT. With its full motion, wide field-of-view visuals, programmable force-feel system and the comprehensive FLIGHTLAB modelling environment, we describe the HELIFLIGHT system as high fidelity and the first year of utilisation saw extensive use in a variety of handling qualities and pilot-vehicle technology research and teaching. Some of these are described in the paper and from a year of many highlights, the EU-funded programme to develop handling qualities for a civil tilt rotor aircraft is selected to demonstrate the versatility of the HELIFLIGHT system.
Curve fitting approach for transonic flutter prediction
Authors: Sedaghat A. , Cooper J. E. , Wright J. R. , Leung A. Y. T.
Published: July 2022

This paper outlines an initial investigation for determining nonlinear aerodynamics for unsteady transonic flows through the use of curve fitting unsteady computational fluid dynamics (CFD) data. The full aerodynamics including linear and non-linear aerodynamics can be identified as a polynomial function. Through the curve fitting method, the important non-linear terms can be identified and the smaller terms can be neglected. Having modelled the non-linear aerodynamics and included into the aeroelastic model, the characteristics and stability of non-linear aeroelastic system can then be investigated using normal form theory. The methodology is demonstrated upon a simple two-degrees-of-freedom aeroelastic wing model with structural and aerodynamics nonlinearity. A good agreement is obtained for all cases studied between analytical and simulation results.
Numerical investigation of staged transverse sonic injection in Mach 2 stream in confined environment
Authors: Chakraborty D. , Roychowdhury A. P , Ashok V. , Kumar P.
Published: July 2022

Transverse sonic injection, usually in a staged manner, in a confined environment is a necessity in the design of an efficient combustion chamber. The design requires an analysis of the mixing of the injectant with incoming stream as efficient combustion depends upon good mixing. This kind of analysis needs numerical model/simulation to assess the mixing of the two streams. To determine the suitability of an existing software package for such a study, staged transverse sonic injection into a Mach 2 stream in a confined environment is taken as a test case. The experimental conditions of McDaniel et al are reproduced for this simulation. In this experiment, staged transverse injection of sonic jet behind the backward facing step in Mach 2 stream was carried out and profiles of various flow parameters were measured. The numerical simulation solves the 3D Navier-Stokes equations with a k – ε turbulence model using the PARallel Aerodynamic Simulator PARAS3D. Computed results show a good match for injectant penetration profile although the computations predict slightly higher penetration near the orifice location. Detailed comparison of flow parameter profiles between computed and experimental data reveal that in the zone away from the injection orifice, computations predict the flow field reasonable well. However, in the vicinity of the orifice, there are some differences between experimental data and computed results. These differences could be due to non-uniform inlet profile in the experiment and/or inadequacy of the turbulence model considered in the study.
An investigation into the longitudinal dynamics and control of a flapping wing micro air vehicle at hovering flight
Authors: Loh K. , Cook M. , Thomasson P.
Published: July 2022

This paper describes the research into the flight dynamics modelling and flight control of a flapping wing micro aerial vehicle (MAV). The equations of motion based on a multi-body representation of the vehicle and the flapping wings were derived and form the basis for the simulation program, which was developed using MATLAB and SIMULINK. The aerodynamic forces were obtained through experimental methods and form the basis for the aerodynamic model.

The hovering and low speed flight of the MAV was investigated using a SIMULINK simulation model. Various flight control concepts, inspired by observation of insect and bird flight, were investigated in some detail. The concepts include the control of flap frequency, flap and pitch phasing (wing beat kinematics) and shift in centre of gravity position. The paper concludes with a comparison of the control concepts and their feasibility for a practical vehicle application.
Reduction of helicopter vibration through cyclic control of variable orifice dampers
Authors: Anusonti-Inthra P. , Gandhi F. , Miller L.
Published: July 2022

The present study demonstrates that cyclically varying the damping coefficient of controllable lag and flap dampers can reduce the 4/revvibratory hub loads of a four-bladed hingeless rotor helicopter in high speed forward flight. Gradient-based optimization is used to determine the optimal multi-cyclic damping variation inputs that minimise a composite vibration index comprising of all six components of vibratory hub loads. Optimal 2/rev and 3/rev variations in the lag damping coefficient virtually eliminate the vibratory hub drag force and yawing moments, and produce small reductions in the vibratory hub side force. The optimal lag damping variations, interestingly, produce increases in the 3/rev and 5/rev components of the blade root drag shear, that cancel the contributions of the blade root radial shear to the vibratory in-plane hub forces. Despite some increases in higher harmonics of blade response, damper loads, and blade and flexbeam root loads, the lower harmonics and the peak-to-peak values show little change, implying that blade and damper fatigue life would not be adversely affected. When optimal 2/rev and 3/rev variations in flap damping coefficient are introduced in conjunction with the optimal lag damping variations, 30% reductions in the hub vertical vibrations are obtained, in addition to the previous reductions in the vibratory in-plane forces and yawing moment. The cyclic flap damping variations reduce the higher harmonics of the blade root vertical shear. Reductions in hub vibration levels are obtained over a range of forward flight speeds.
Non-linearities in flight control systems
Authors: Fielding C. , Flux P. K.
Published: July 2022

Non-linear behaviour is usually undesirable for the operation of any system and it needs to be minimised in flight control systems in order to provide the pilot with a predictable and well-behaved aircraft. The non-linear response characteristics exhibited by all aircraft and their flight control systems can be characterised by using nonlinear functions to simulate and analyse their behaviour. This paper explores the types of physical non-linearities that exist in aircraft flight control systems and provides some examples. It describes how the non-linear stability might be analysed and addresses the subject of actuation systems modelling. The final section provides recommendations for minimising non-linear behaviour and gives some general guidelines on how to deal with non-linear characteristics.
Aero engines of the future
Authors: Ruffles P. C.
Published: July 2022

One hundred and two years ago, after the Wright brothers had just attempted another unsuccessful flight, they predicted that it would be another 50 years before manned flight was achieved. Only two years later and 100 years ago this year, Orville Wright achieved the first powered flight at Kitty Hawk in North Carolina, illustrating just how difficult it is to predict the future and at the same time launching the pioneering age of aviation.
Aircraft structures in the century ahead: From arts to science, from craftsmanship to multidisciplinary design and engineering
Authors: Beukers A. , van Tooren M. , Vermeeren C.
Published: July 2022

The first centennial of man's first powered flight, which was performed by Wilbur (1867–1912) and Orville (1871–1948) Wright (Fig. 1) will be celebrated in 2003. These brothers' unique and trendsetting enterprise, their skills to develop, build and commercialise controllable and load-carrying flying machines, formed the first example of a private interdisciplinary aerospace development and design initiative. It was at the same time a rare example of entrepreneurial engineering. Their work involved wind-tunnel testing of lifting devices and full-scale tests of major structural components. Equally if not more importantly they developed an essential propulsion system consisting of a lightweight 36hp engine with four cylinders in line and a fuel injected carburettor. This engine propelled two pusher propellers through a drive system of chains. Moreover they developed the systems to control their flight. The twistable wing tips that control rolling and heading during the flight were the last remains of the former trend to mimic bird flight.
Flocking of autonomous unmanned air vehicles
Authors: Crowther B.
Published: July 2022

The use of large numbers of unmanned air vehicles in a given air space presents a challenge for conventional air traffic control methods. Flocking (or schooling, swarming or herding) in nature arises when mobile organisms find benefit in living at high densities. The present paper applies rules of flocking (cohesion, alignment, separation, and migration) to the problem of managing the flight of a number of autonomous unmanned air vehicles. A six-degree of freedom aerodynamic model of an existing UAV is used to simulate the flocking flight vehicles. It is found that application of the cohesion and alignment rules is sufficient to generate true flocking behaviour in that the flight vehicle density is increased and the flock members converge on a common heading. Increasing rule strength reduces the time taken to achieve flocking behaviour. However increasing rule strength too far leads to oscillatory or unstable flight paths. It is found that flock behaviour can be adequately described using the time histories of two statistical parameters: the mean radius between flock members and the standard deviation of the flock members’ heading angles.
A flight test to demonstrate flutter and evaluate the flutterometer
Authors: Lind R. , Voracek D. F. , Truax R. , Doyle T. , Potter S. , Brenner M.
Published: July 2022

A project was recently completed that investigated the ability to predict the onset of flutter using tools like the flutterometer. This project used an experiment called the aerostructures test wing that was flown while mounted to the flight test fixture on an F-15. Several flight tests were conducted to expand the envelope and determine the aeroelastic dynamics of the experiment. The final flight ended with destruction of the experiment due to the onset of flutter. The flutterometer attempted to predict this onset by analysing the flight data. The results indicate the flutterometer is able to generate a conservative estimate of the flight conditions associated with flutter. This paper details the flight tests of the experiment and the resulting predictions from the flutterometer.
A dynamically fuzzy gain – scheduled design for missile autopilot
Authors: Lin Chun-Liang , Hwang Chai-Lin
Published: July 2022

A dynamic backpropagation training algorithm for an adaptive fuzzy gain scheduling feedback control scheme with the application to missile autopilots is developed. This novel design methodology uses a Takagi-Sugeno fuzzy system to represent the fuzzy relationship between the scheduling variables and controller parameters. Mach number and angle-of-attack are used as measured, time-varying exogenous scheduling variables injected into the control law. By incorporating scheduling parameter variation information, the adaptation law for controller parameters is derived. Results from extensive simulation studies show that the presented approach offers satisfactory controlled system performance.
Optimisation of noise abatement arrival trajectories
Authors: Visser H. G. , Wijnen R. A. A.
Published: July 2022

This paper describes an optimisation study concerning arrival trajectories that has been conducted using a recently developed tool for the analysis and design of noise abatement procedures around airports. This new tool combines a noise model, a geographic information system, and a dynamic trajectory optimisation algorithm. The optimisation algorithm generates routings and flight-paths that minimise the noise impact in the residential communities surrounding the airport, while satisfying all imposed operational and safety constraints. The study on arrival trajectories presented herein complements an earlier study involving departure trajectories. Although the numerical results shown pertain to a particular example airport, viz Amsterdam Airport Schiphol, the study actually focuses on the development of a generic methodology that could be applied to any given airport. The results clearly demonstrate the effectiveness and flexibility of the developed tool.
Design aspects of the adaptive wing — the elastic trailing edge and the local spoiler bump
Authors: Monner H. P. , Breitbach E. , Bein Th. , Hanselka H.
Published: July 2022

Market research predicts a large growth in numbers of passengers as well as airfreight volume for the aircraft industry. An expected concomitant increase in competition for the European aircraft industry demands that the efficiency of new aircraft has to be drastically improved. One approach to achieve this is the aerodynamic optimisation of the wing. The fixed wing is designed optimally only for one flight condition. This flight condition is described by the parameters altitude, Mach number and aircraft weight which vary continuously during the mission of the aircraft. Therefore, the aircraft is just periodically near the chosen design point. To compensate for this major disadvantage, an adaptive wing for optimal adaptation and variation of the profile geometry to the actual flight conditions is under development. DaimlerChrysler Aerospace Airbus, DaimlerChrysler Research and the German Aerospace Centre (DLR) are working as project partners on concepts for a variable camber and a local spoiler bump. In this paper structural concepts developed by the German Aerospace Centre for both objectives will be presented. The concepts are designed under the aspect of adaptive structural systems and require a high integration of actuators, sensors and controllers in the structure. Special aspects of the design will be discussed and first results, analytical, numerical as well as experimental, will be presented. Part of the concept design is also the development of new actuators optimised for the specific problem. A new actuator concept for the spoiler bump based on a cylindrical tube and activated either by pressure or multifunctional materials (e.g. shape memory alloys) will additionally be shown.
A new approach to the third order calibration of internal strain gauge balances used for aerodynamic load measurement
Authors: Niven A. J. , Tait S. W.
Published: July 2022

With respect to wind tunnel aerodynamic load measurement, an internal strain gauge balance (often referred to as a sting balance) is essentially a compact load cell designed to fit within a cavity of the aerodynamic body and form a link between the model and a fixed ground point via a sting support system. The structure of an internal strain gauge balance is designed to incorporate a series of planar surfaces such that the deflection of each surface is predominantly induced by a unique aerodynamic load. Strain gauges, mounted on groups of surfaces in a Wheatstone bridge arrangement produce output signals proportional to the applied aerodynamic loads. A strain gauge balance is calibrated by applying known loads, measuring the bridge outputs and then formulating an equation which relates the two variables together. Although calibration techniques are well established, reservations have been recently expressed concerning the ability of the associated calibration equation to satisfactorily model the response of the balance when subjected to a six component aerodynamic loading. This generally accepted calibration equation (referred to here as the traditional equation) results in a quadratic approximation to the behaviour of the output signals with applied loads, whereas a more appropriate variation would be cubic. Other limitations of the traditional calibration equation are that the behaviour of the balance to two simultaneously applied loads is based upon limited combinations of the two applied loads, and that the acquisition of the required loads from the strain gauge signals is frequently based upon an approximate matrix inversion method. The proposed calibration equation, described within this paper, models the behaviour of the sting balance to the third order, takes account of all possible combinations of two simultaneously applied loads, and avoids the use of an approximate matrix inversion when deriving the desired aerodynamic loading from the signal outputs. It is also shown that the proposed method may be used to determine the interaction of all possible combinations of up to three simultaneously applied loads.
Experimental audit of the mixing-plane approach to turbomachinery analysis and a review of alternative multi-row techniques
Authors: Lockwood C. , Ivey P. C. , R. G. Wells
Published: July 2022

Detailed numerical comparisons of pressure and flow angle measurements made in stage three of a four-stage, large scale, low speed, axial compressor are presented. The measurements are in both the rotating and stationary frame and were obtained as part of a BRITE/EURAM collaborative study of cantilevered and shrouded-stator compressor configurations. The numerical analysis is 3D, considers three blade rows simultaneously and incorporates multiple row effects by use of a conservative mixing-plane model allowing circumferential variation at the mixing plane.

The paper discusses the early results of a study sponsored by Alstom Gas Turbines to examine steady-state, multiple blade-row modelling techniques. Growth in the endwall flow region due to multi-row effects is revealed from both the numerical and experimental results. The numerical simulation is conducted without altering blade gap spacings to assist numerical stability; the axial gap is increasingly being seen as a critical performance parameter for multiple row analysis. The limitations inherent in an approach using mixing-planes are presented and a review of alternative, more rigourous, treatments of these effects is then discussed. These treatments attempt to retain the unsteady flow structure in a steady-state model by the derivation of so-called deterministic stresses.
The influence of mid-chord battle damage on the aerodynamic characterstics of two-dimensional wings
Authors: Irwin A. J. , Render P. M.
Published: July 2022

This paper briefly considers the method of simulating gunfire damage to a wing and outlines the key basic assumptions used in modelling. The results of qualitative and quantitative investigations into the aerodynamic characteristics of a wing damaged at quarter chord are then presented. The results are discussed in terms of flow mechanisms, changes to surface pressure distributions and increments in lift, drag and pitching moment coefficients. For the damaged wing, the influence on force and moment coefficients was attributed to flow through the damage. This through flow was driven by the pressure differential between the upper and lower wing surfaces, and took one of two forms. The first form was a ‘weak-jet’ which formed an attached wake and resulted in small changes in force and moment coefficients. The second form resulted from either increased incidence, or damage size. This was the ‘strong-jet’, where through flow penetrated into the freestream flow, resulting in separation of the oncoming surface flow, and the development of a larger separated wake with reverse flow. The effect on force and moment coefficients was significant. The paper also compares the structure of the damage through flow with previously published results for jets in crossflows. Many similarities in the flow features were identified, although there were significant differences in the surface pressure distributions for the two cases.
An investigation of the grid fins as control surface devices for missiles
Authors: Chen S. , Khalid M. , Xu H. , Lesage F.
Published: July 2022

Recently, grid fins have been receiving increasing attention as a practical and efficient means of controlling missile trajectory. Preliminary studies at IAR have demonstrated that modern CFD methods can be used for computing flows past complex grid fin type configurations, and that these methods are more soundly physically based than the earlier vortex lattice and/or shock expansion methods.

The current paper addresses the issue of the grid fin size, in terms of both the panel thickness and the frontal shape. The study covers three thicknesses for the grid fin panel, with front shapes having a simple blunt square face, as well as a sharp knife-edge shape. In addition, an important aspect of the present investigation is to quantify the aerodynamic effect of the ramp fairing installed immediately upstream of the blunt base upon which the grid fin assembly resides. A comparison of flow field characteristics and aerodynamic coefficients of the grid fin assembly, with and without the fairing ramp, would provide a direct means of evaluating the effect of the ramp. At this stage, the investigations are based on Euler calculations. The present study focuses on a standard grid fin configuration mounted on a generic cylindrical body.
The Cranfield aircraft handling qualities rating scale: a multidimensional approach to the assessment of aircraft handling qualities
Authors: Harris D. , Gautrey J. , Payne K. , Bailey R.
Published: July 2022

The Cooper-Harper scale is currently the only well-established scale for assessing aircraft handling qualities. However, as a result of having a unidimensional format the Cooper-Harper scale lacks diagnostic power and has also been criticised for exhibiting poor reliability. The Cranfield Aircraft Handling Qualities, Rating Scale (CAHQRS) is a new, multidimensional rating scale using concepts from two established scales, the NASA-TLX workload scale and the Cooper-Harper scale. This paper provides an overview of the development of the CAHQRS and the results from a series of validation trials in an engineering flight simulator. An in-flight refuelling task and an approach and landing task using a range of control laws were used in these evaluations. The results showed that the CAHQRS had high positive correlations with the Cooper-Harper scale. However, the CAHQRS also demonstrated greater validity, diagnostic power and higher test/re-test reliability than the previous scale.
Inertial navigation and its impact on future avionics systems
Authors: McKinlay W. H.
Published: July 2022

It is now over twenty years since the first experimental inertial navigation system was built and tested in America, by MIT. Over that period inertial navigation has come of age as a technology, and many thousands of inerital systems are in service in civil and military aircraft.

Ferranti Limited have been active in this field over 15 years, developing and producing both the basic inertial instruments and complete systems for a range of aircraft and space applications. The first system was produced for the TSR-2, which was cancelled at the prototype stage. But a first generation production system has now been in RAF service for some time. A second generation system, now at an advanced stage of test and development, will equip the European Multi Role Combat Aircraft (MRCA). A version of the same system has been adopted in Japan.
Land development aircraft
Authors: Lockspeiser David
Published: July 2022

Opinions have been expressed in the past by such eminent people as the Duke of Edinburgh and E. A. Gibson and the NZ Civil Aviation Authority to this Society that there is a need throughout the world for an airborne equivalent of the tractor, or Land Rover. Current observations and market survey confirm that there is an expanding market in which this new aircraft has a huge role to play in agriculture and general land development because the existing specialist crop sprayers and converted conventional aircraft can only play but a part.
Putting a value on noise
Authors: Richards E. J.
Published: July 2022

Problems of noise at airports have now been with us for over a quarter of a century and in many ways the situation seems to be more acute than ever before. The promise of new and better sited national airports has receded to such an extent that all that remains is a vague threat of the need to find a cheaper but less environmentally suitable site, and an exhortation to permit added traffic to operate from existing airports, even though the local communities have expressed their displeasure most forcefully. The introduction of the Concorde, unlikely as it is to always meet the old noise rules, let alone the new ones, makes a mockery of those operators who are willing and have striven to accept a policy of progressive reductions of noise limits, and the present governmental tardiness to proceed with plans for retrofit will add to this unwillingness.
A view of air freight developments in the next decade
Authors: Olason M. Lynn , Reynolds A. Dean
Published: July 2022

The purpose of this paper is to provide a view of air freight developments over the next decade.

Before we try to do that, it might be very useful to look back over the past 10 or 15 years to see where we are and to develop some understanding of how we got into the position that we find ourselves in today. Therefore, we are going to go back over the past 15 years and review the economic situation and assess the impact of selected air freighters in an attempt to develop some guidance in forecasting what we might look forward to in the next 10 years.
Rewards and penalties for suppliers of equipment
Authors: Passey R. D. C.
Published: July 2022

Over the years, the evolution of legal and contractual relationships between the suppliers of equipment and their customers has been fragmentary. Fiscal incentives for the supply of economical equipment have been rare, while incentive contracts for developing military equipment have been the cause of some controversy, particularly as regards allowances for inflation.

Immediate interests have tended to take precedence over longer term characteristics, which are often of more importance to customers. Relative merits of rewards, penalties and other motivating factors have received little attention in the literature, and philosophical considerations have been neglected.
Engineering and development problems of Spacelab
Authors: Hoffmann H. E. W.
Published: July 2022

In the past thirty years the exploration and exploitation of space has been one of the few new eras into which man has penetrated and opened a new frontier. Naturally, this drive was made by the two world powers which possess the resources and which are pushed by their competitive fight for public prestige and world-wide admiration. Once again Europe supplied many of the ideas and many of the leading people. And what did we do for ourselves?

In the beginning of post Second World War space activities we missed the start. The first satellites were already in orbit when the first space activities in Europe were proposed. But when we began to move in 1961 we began to move in the right direction. For our purpose the essential factor was the creation of the European agencies—ELDO and ESRO at that time—in which the national efforts of the member states were combined and co-ordinated towards the common goal.