bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Fatigue and Other Airworthiness Aspects
Authors: Williams J. K. 
Published: July 2016

In this paper the emphasis is on safety problems connected with the use of light fixed-wing aircraft for agricultural purposes. Most of the aircraft concerned are between 2000 and 6000 lb all-up weight and are single piston-engined types. About 97 per cent of all hours flown in agricultural aviation all over the world are by such small fixed-wing aircraft, the remainder by larger aircraft such as the DC-3 and helicopters.The mass of statistics available on this type of flying is therefore confined to the small fixed-wing aircraft and since this type is obviously the most important with respect to this activity, then it is appropriate to concentrate on this type.
Magnetic Suspension and Balance System for Wind Tunnel Application
Authors: Chrisinger J. E. , Tilton E. L. , Parkin W. J. , Coffin J. B. , Covert E. E. 
Published: July 2016

SummaryIn this article a magnetic suspension and balance system suitable for wind tunnel application is discussed. General considerations are presented that illustrate the nature of the problems to be solved as well as one solution of these problems.Finally some initial wind tunnel data are presented.
The Stiffening Effect of an Overhang in a Circular Plate
Authors: Mansfield E. H. 
Published: July 2016

SummaryThe problem considered is that of a circular plate which is supported along an internal concentric circle and subjected to uniform pressure over the area bounded by the support line; the outer edge of the plate is free. This form of loading and support is used in the testing of glass panels, where the rigidity of the panel is determined from a measurement of the central deflexion. However, the formula in current use does not allow for the stiffening effect of the overhanging outer annulus.
The Engineering Reliability of Shaft-Driven Helicopters
Authors: Fitzwilliams O. L. L. 
Published: July 2016

I am honoured to have been invited to give this Third Cierva Memorial Lecture on a subject which has a general application to all forms of aircraft, and which is central to any consideration of the future of the helicopter.Reliability is a problem, the extent and urgency of which can only be appreciated fully and at first hand by the operator of a large fleet of aircraft, but most of the discussions and documents which have helped to lay the basis for this paper are not for general publication. I believe that this has helped me to concentrate on the essentials of the problem, but there is a danger that the simple arguments on which the paper is based may not carry the emphasis needed to convey to my colleagues the critical attitude of the operators.
Spar-Web Design in Relation to Thermal Stresses-The Corrugated Web
Authors: Williams D. 
Published: July 2016

SummaryThe possibilities of a vertically-corrugated web as a means of reducing thermal stresses naturally have for some time been generally appreciated by designers. The stress relief to be expected is examined in some detail here. It is shown that quite shallow corrugations can be effective in reducing thermal stress and that a flange-to-web connection at corrugation-pitch intervals can offer substantial advantages over a more continuous type of connection. Arguments are presented to show why straight-sided corrugations are superior to curved ones.
The Story of Indian Air Transport
Authors: Tata J. R. D. 
Published: July 2016

The Sixteenth British Commonwealth Lecture, The Story of Indian Air Transport, by Mr. J. R. D. Tata, Chairman of Air-India International, was given before a distinguished audience on 18th November 1960 at the Institution of Mechanical Engineers, Birdcage Walk, London, S.W.1.The President of the Society, Dr. E. S. Moult, C.B.E., B.Sc., F.R.Ae.S., M.I.Mech.E., presided at the meeting. Before introducing the Lecturer the President explained that hitherto the election of Fellows had been initiated by the Council and announced once a year but, under the new By-Laws, Fellowship was to be regarded as a position which could be attained by any qualified member who had reached a position of eminence and responsibility in the profession of aeronautics. At the same time it had been decided that the announcement of such elections should be made not just once a year, but on occasions such as this.The names of 22 members who had been elected to Fellowship since May 1960 were then read out by the Secretary. (These names were published in the December Journal–Ed.)After congratulating the new Fellows, Dr. Moult said that the British Commonwealth series of lectures started at the end of the War in 1945, and had continued annually until the present day. Throughout the years they had had a series of outstanding lectures on subjects associated with aeronautics in the Commonwealth, given by most distinguished lecturers. The stature of this lecture was set for all time in 1954 when His Royal Highness The Duke of Edinburgh addressed them on “Aviation and the Development of Remote Areas”. Now they were to hear about the growth of aviation in one of the great members of the Commonwealth. Air Transport in India was now thirty years old1 and there was no one more suited to tell the story of that thirty years than their lecturer, Mr. J. R. D. Tata.Mr. Tata had been actively associated with this development all his working life. Indeed, it was true to say he had had a major part in it. He learned to fly in 1929 and personally flew the first scheduled transport service in India in 1932. He had been associated with aviation throughout all these years and a few years ago was president of I.A.T.A., the International Air Transport Association; he was now Chairman of Air-India International. He had great pleasure in asking Mr. Tata to give the Sixteenth British Commonwealth Lecture, “The Story of Indian Air Transport.”
Some Old Masters of the Society, and their Far-reaching Influence in Aviation
Authors: Gibbs-Smith Charles H. 
Published: July 2016

Inventors who work in secret, and whose vital creations never see the light of day until the world has passed them by, are mostly figures of romantic fiction. Most inventors take good care that their devices are brought to public notice, preferably after patents have been granted to them; and one of their main concerns in the 19th century was therefore the channels of communication open to them.Sir George Cayley wrote, in 1837, that “the experiments that have been made, and the investigation which it (the subject) has undergone, lie almost unconnected in the periodical publications of the last thirty years; and hence, every new speculator on the possibility of steering balloons takes up the subject merely on his own view”.
British Aeronautical Research Facilities
Authors: Hilton W. F. 
Published: July 2016

“And as in uffish thought he stood,The Jabberwock, with eyes of flame,Came whiffling through the tulgey wood,And burbled as it came!“Scarcely has the final history of the steam train been written, than I am asked to write the history of the aeroplane, from the research facilities’ point of view. It can only be this nostalgia for the past which has enabled me to secure the willing help of so many people in the brief three and a half weeks allowed for the compilation of this paper. Of necessity it must be incomplete, but is, I trust, accurate.
Controlled Markov set-chains with discounting
Authors: Kurano Masami , Song Jinjie , Hosaka Masanori , Huang Youqiang 
Published: July 2016

In the framework of discounted Markov decision processes, we consider the case that the transition probability varies in some given domain at each time and its variation is unknown or unobservable.
To this end we introduce a new model, named controlled Markov set-chains, based on Markov set-chains, and discuss its optimization under some partial order.
Also, a numerical example is given to explain the theoretical results and the computation.
A comparison of the ordinary and a varying parameter exponential smoothing
Authors: Bonsdorff Heikki 
Published: July 2016

An adaptive-type exponential smoothing, motivated by an insurance tariff problem, is treated. We consider the process Zn
= ß(Zn –

1)Xn
+(1 – ß (Zn

–
1))Zn

–
1, where Xn
are i.i.d. taking values in the interval [0, M], M ≦ ∞ and ß is a monotonically increasing function [0, M] → [c, d], 0 &lt; c &lt; d &lt; 1.
Together with (Zn
), we consider the ordinary exponential smoothing Yn
= αXn
+ (1 – α)Yn –

1 where α is a constant, 0 &lt; α &lt; 1. We show that (Yn
) and (Zn
) are geometrically ergodic Markov chains (in the case of finite interval we even have uniform ergodicity) and that EYn, EZn
converge to limits EY, EZ,
respectively, with a geometric convergence rate. Moreover, we show that Ez
is strictly less than EY
= EXn.
Estimation for a family of life distributions with applications to fatigue
Authors: Birnbaum Z.W. , Saunders S.C. 
Published: July 2016

Summary
The estimation problem is studied for a new two-parameter family of life length distributions which has been previously derived from a model of fatigue crack growth. Maximum likelihood estimates of both parameters are obtained and iterative computing procedures are given and examined. A simple estimate of the median life is exhibited, shown to be consistent and then compared, favorably, with the maximum likelihood estimate. More important, the asymptotic distribution of this estimate is shown to be within the same class of distributions as the observations themselves. This model, and these estimation procedures, are tried by fitting this distribution to several extensive sets of fatigue data and then some comparisons of practical significance are made.
Modelling the flow of coalescing data streams through a processor
Authors: Anantharam V. 
Published: July 2016

In a data processing network, two data streams A and B arrive at a node independently at the same Poisson rate λ. Service at exponential rate µ can take place iff there is at least one of each of A and B present. The output is the combined processed data AB. We consider models of this situation with finite buffers, with infinite buffers and with finite buffers for the excess of each input type over the other. We apply the filtering theory for point process functionals of a Markov chain to study whether the output flow is Poisson in equilibrium. The motivation is to examine, if the output is to subsequently be processed by a queueing system, whether it can be treated as an independent Poisson input to that system.
A result of independent interest is that a subset of transitions of a countable-state Markov process does not yield a Poisson process when counted, if the rate matrix of counted transitions is nilpotent, and we prove a generalization of Pakes' lemma for countable-state Markov chains.
Construction of first-passage-time densities for a diffusion process which is not necessarily time-homogeneous
Authors: Jáimez R. Gutiérrez , Gonzalez A. Juan , Román P. Román 
Published: July 2016

In Giorno et al. (1988) a new method for constructing first-passage-time probability density functions is outlined. This rests on the possibility of constructing the transition p.d.f. of a new time-homogeneous diffusion process in terms of a preassigned transition p.d.f. without making use of the classical space-time transformations of the Kolmogorov equation (Ricciardi (1976)).
In the present paper we give an extension of this result to the case of a diffusion process X(t) which is not necessarily time-homogeneous, and a few examples are presented.
Generalized adaptive exponential smoothing procedures
Authors: Herkenrath Ulrich 
Published: July 2016

The classical exponential smoothing procedure to be applied to a sequence of observations is modified into some adaptive variants and also generalized to the recursive scheme
This means that given the history of observations and smoothed values up to time n, the updated smoothed value Wn +

1 is given by a function u of Wn
and Xn
, which satisfies only certain structural properties. We study these procedures within the framework of random systems with complete connections and exploit results from Markov process theory to study the sequence . A broad class of ‘smoothing functions' u, which induce sequences with nice statistical properties, is presented. A method to estimate the limit of the expected smoothed values is also developed.,
Convex majorization with an application to the length of critical paths
Authors: Meilijson Isaac , Nádas Arthur 
Published: July 2016

1.

(Y) for all non-negative, non-decreasing convex functions φ (X is convexly smaller than Y) if and only if, for all .

2.
Let H be the Hardy–Littlewood maximal function HY
(x) = E(Y – X | Y &gt; x). Then HY
(Y) is the smallest random variable exceeding stochastically all random variables convexly smaller than Y.

3.
Let X
1
X
2 · ·· Xn
be random variables with given marginal distributions, let I
1,
I
2, ···, Ik
be arbitrary non-empty subsets of {1,2, ···, n} and let M = max (M is the completion time of a PERT network with paths Ij
, and delay times Xi
.) The paper introduces a computation of the convex supremum of M in the class of all joint distributions of the Xi
's with specified marginals, and of the ‘bottleneck probability' of each path.
A stochastic calculus and its application to some fundamental theorems of natural selection
Authors: Mode Charles J. 
Published: July 2016

Summary
In this paper a stochastic calculus, based on limits in quadratic mean and in probability, is introduced and applied to some fundamental theorems of natural selection. The paper is divided into five principal sections. In Section 2 some elements of stochastic calculus are given, and in Section 3 the stochastic calculus is applied to the haploid case. Section 4 is devoted to the development of an analysis of variance structure applicable to a haploid population, and in Section 5 the results of Sections 3 and 4 are generalized to cover the diploid case. Finally, Section 6 is devoted to two specific examples in which the results of previous sections apply.
Some Economic and Operational Questions
Authors: Jackson C. H. 
Published: July 2016

The argument for the supersonic transport seems to run as follows: it offers a new and faster way to go places; it might not cost more to do so; it ought to create new wealth, and its influence on human affairs, although not clearly foreseeable, surely will be beneficial. There is a certain amount of evidence to warrant optimism; there are issues of national prestige and well-being; the technical challenge is exciting; so “ Let us somehow find finance and proceed.”Operators agree that the design and operational problems of supersonic aircraft, one of the possible great advances in transport, are complex and interesting; they might also speculate on its likely social implications, though this is an unrewarding pastime. The operators accept that the aircraft probably will be developed, for it is as much a challenge of the times as have been all the great innovations of routes and vehicles from Columbus right through to our day; but as has always been the case, before any commitment, they must seek assurance of ultimate economic soundness.
A High Temperature Decompression Chamber for Developing Aircraft Environmental Control Systems
Authors: Furlong O. D. 
Published: July 2016

The greatly increased performance of both civil and military aircraft since the Second World War has raised problems undreamt of at an earlier period and, from the simple measures originally introduced to improve pilot’s well-being, have sprung the complex installations which are now essential for human survival and comfort and to ensure the proper functioning of vital equipment carried in present day machines.The term “Environmental Control System” is used for convenience to cover collectively the various cabin and equipment bay, pressure, temperature and humidity control systems that are fitted.
The Validity of the Initial Strain Concept
Authors: Argyris J. H. , Kelsey S. 
Published: July 2016

We must thank Dr. Grzedzielski for the clarification of his argument and notation contained in his second note. Unfortunately, this note only shows more clearly the fundamental misconceptions and errors in his arguments. Our own argument as to the generality and validity of the initial strain concept remains unaffected.In our previous note, we were concerned to explain the initial strain concept, which Dr. Grzedzielski had criticised as “ an oversimplification not generally admissible “ both in the calculation of thermal stresses and as a device to simulate the effects of structural cut-outs and modifications. Here, we prove independently by a direct consideration of the compatibility conditions in the final structure, that the modified stress distribution given by our analysis is the correct one—regardless of the extent of the coupling in the flexibility matrix.
The Development of Short Range Air Transport Through The Use of V/STOL Aircraft
Authors: Ziegler Henri 
Published: July 2016

The Fourteenth Louis Bleriot Lecture “ The Development of Short Range Air Transport through the use of V/STOL Aircraft,” by General Henri Ziegler, General Manager, S. A. Louis Breguet, was given before a distinguished audience which included a number of visitors from France, on 23rd March 1961 in the Society's Lecture Theatre.The President, Dr. E. S. Moult, C.B.E., B.Sc.(Eng.), F.R.Ae.S., M.I.Mech.E., presided at the meeting. Before the formal proceedings the names of 17 members elected to Fellowship of the Society since December 1960 were read by the Secretary. (These names were published in the January, February and March JOURNALS—Ed.)After congratulating the new Fellows, Dr. Moult said that this was one of those great occasions of the Society when they united with their friends from France to revere the memory of Louis BleYiot, the first aviator to cross the Channel. This was on the 25th July 1909; since then, they would agree, great things had happened in the field of aeronautics.
An Experimental Investigation of Base Flows at Supersonic Speeds
Authors: Badrinarayanan M. A. 
Published: July 2016

SummaryDetailed measurements in the wake flow behind blunt based two-dimensional and three-dimensional bodies have been made at M = 2. The results throw some light on the behaviour of separated flows and indicate the importance of flow reversal. The results for the two-dimensional body are in agreement with the Crocco and Lees’ theory on separated shear flows. A preliminary study of the effect of air injection at the base shows that the base pressures increase significantly.
Stress Concentrations in Tensile Strips with Central Notches
of Varying End Radii
Authors: Papirno Ralph 
Published: July 2016

SummaryUsing relations derived by Dixon and Inglis, the values of the elastic stress concentration factor for a fixed length notch in a finite width tensile strip with a varying notch end radius have been obtained in the form:Photoelastic tests on internally notched tensile strip models showed excellent agreement with the analytical results.
Economics of Ramjets as Satellite Launchers
Authors: Probert R. P. , Mallinson D. H 
Published: July 2016

Although this talk, to conform to the general pattern of the Symposium has the word “Economics” in its title, the plain fact is that nobody at the present time is able to make a reliable assessment of the economics, in the usual financial sense, of ramjet launchers.Rockets have already demonstrated their ability to fill this role and assessments of the cost can be based upon real experience, as Mr. Rothrock's paper clearly shows. The use of ramjets for this duty, or more strictly for part of the duty, since we cannot hope to provide ramjet power all the way from take-off to orbit, remains problematical. The first step must be to prove the feasibility of using ramjets and only when some of the major problems on which feasibility hinges have been solved, can any really rational assessment of the probable cost be made.
Economics of Ground Stations
Authors: Milne K. 
Published: July 2016

The Ground Stations to be discussed are the large Radio Stations required for a variety of Astronautical applications. The principle categories are:–
Radio Astronomy,Telemetry and Control,Communications,Military applications,
and many examples can be found in each category. The Radio Astronomer is interested in the distribution, intensity and spectrum of all extra-terrestial radiations. He will also be interested in telemetry of signals from earth satellites used as observatories beyond the earth's atmosphere. At the other end of the scale, the military authorities are involved in the detection and tracking of hostile satellites as well as the telemetry of data from their own reconnaissance satellites.
Elastic Instability of a Stringer on Thin Sheets
Authors: Caldwell J. B. 
Published: July 2016

Figure 1 illustrates a load diffusion problem which occurs in ship structural design, and which may also be relevant to aircraft structures. A load applied to one end of a stringer is diffused into the attached sheet and eventually reacted by shearing forces at the longitudinal edges. The transverse edges of the sheet and the other end of the stringer are not loaded.Various methods, which differ in their assumptions regarding stresses and displacements in the sheet, are available for tackling this problem. For calculating the distribution of load or stress in the stringer it makes little difference which method is used. The “finite stringer” method of reference (1) is the simplest and should be sufficiently accurate for most cases.
Radioactive Contamination of Commercial Aircraft
Authors: Doran D. 
Published: July 2016

SummaryWhen atmospheric testing of nuclear devices was resumed in the latter part of 1961 it was found that certain commercial aircraft were being contaminated by airborne radioactive debris to such a degree that decontamination was required, with associated protection of personnel. Some airlines seemed reluctant to publish detailed information on the position. BOAC, however, recognised the phenomenon as a virtually permanent one and in recent months has been setting a lead in developing the process of measurement and control from a somewhat academic exercise to a properly understood engineering routine. When the nature of the hazard is understood—and particularly the all-important distinction between external radiation and internal radiation—it can be seen that, in fact, passengers and crews are not at risk at all, and that handling and maintenance personnel need not be concerned if the contaminated surfaces are washed by an essentially wet process and personal hygiene rules are observed where necessary.
Some Boundary Layer Measurements on a Slender Wing at Supersonic Speeds
Authors: Griffiths R. T. 
Published: July 2016

SummaryBoundary layer measurements have been made at four positions on a slender gothic wing of aspect ratio 0·75. Test's were made over a range of incidence at M=1·42 and 1·82. With transition fixed by roughness near the leading edge the boundary layer thickness varied little with small positive or negative incidence but was reduced at larger incidences, this being most marked at positive incidence for positions nearest the leading edge due to the influence of the wing vortex. With the exception of positions in the vicinity of the vortex, a good estimate of the boundary layer thickness was given by the theory for incompressible flow over a flat plate and an excellent estimate of the variation of local static pressure and Mach number with incidence was given by not-so-slender wing theory.