bluuebunny/crossref_metadata_2025 huggingface dataset:
Roveacrinida (Crinoidea,Articulata) from theSantonian–Maastrichtian (UpperCretaceous) ofEngland, theUS GulfCoast (Texas,Mississippi) and southernSweden
Authors: Gale Andrew Scott
Published: July 2016

Abundant new material ofRoveacrinida from the upperSantonian and lowerCampanian chalk of southernEngland, the lowerCampanianTaylorFormation ofTexas, theMaastrichtianPrairieBluffFormation ofMississippi and the lowerCampanian rocky shoreline deposits ofIvöKlack, southernSweden is described. TheSaccocomidae, subfamilySaccocominae, are represented byCostatocrinusgen. nov., with included speciesC. brydoneisp. nov. (type species) andC. mortimoreisp. nov. TheSaccocomidae, subfamilyApplinocrininae, genusApplinocrinus, includesA. cretaceus(Bather),A. texanusPeck andA. russellisp. nov.Sagittacrinusgen. nov. (type species:S. torpedosp. nov.) is represented only by highly distinctive primibrachials. The ‘ventral cover plates’ ofApplinocrininae are re‐interpreted as modified brachials.Roveacrinidae (Roveacrininae) is represented byRoveacrinus communisDouglas,R. bairstowiPeck andJakeocrinusgen. nov. (type species:J. ellisensissp. nov.). A new subfamily,Hessicrininae, characterized particularly by skeletal reduction through the development of fenestrae and foramina, and many with long processes from radials and basals, is established forPlatelicrinusDestombes &Breton,Lucernacrinusgen. nov. (type species:L. woodisp. nov.),Hessicrinusgen. nov. (type species:H. filigreesp. nov.; alsoH. scalaensissp. nov.),Stellacrinusgen. nov. (type species:S. hugesaesp. nov.; and formacristatusnov.),S. pannosussp. nov., and the aberrantCultellacrinusgen. nov.,which lacks arms (type species:C. gladiussp. nov.). TheSantonian–Maastrichtian roveacrinids represent a fourth and final radiation of the family. Cladistic analysis of theHessicrininae subfam. nov. supports the monophyly of the subfamily, and indicates that the most derived taxa areStellacrinusgen. nov. andCultellacrinusgen. nov. From adaptive morphological data, patterns of distribution and palaeoenvironmental information, it is concluded that these crinoids lived as mesoplankton. The short ranges and wide geographical distribution offer considerable biostratigraphical potential.
Classification and discrimination problems with applications, part I
Authors: Schaafsma Willem , van Vark Gerrit N.
Published: July 2016

This paper presents some of the results of the collaboration of the two authors, a mathematical‐statistician and a physical‐anthropologist, who have worked together since about 1960. Part I will consist of three chapters. Chapter I contains a description of the problems, especially concerning physical anthropology, which constitute the main motivation for this paper. Chapter 2 summarizes well‐known results which are included in order to make the paper self‐contained. Chapter 3 is mainly devoted to theunivariatetwo‐population classification problem and based on assumptions of normality and equality of the variances. Explicit expressions (Section 3.3) and confidence intervals (Section 3.4) arc obtained for the two misclassification probabilities of the maximum likelihood ruleφ* (Section 3.2) which is of application if the two kinds of error are equally bad. A Ncyman‐Pearson formulation is considered (Section 3.7). The asymptotic distribution is derived of an estimator for the posterior probability that the individual comes from Population 2 (Section 3.6). An interesting difficulty, frequently met with in physical anthropology, is that many individuals have to be classified without any (or with only small) reference samples being available from the relevant populations (Section 3.8). Part II will consist of two chapters. Chapter 4 contains new results formultivariateclassification and discrimination problems. Chapter 5 contains applications.
Prioritizing manual test cases in rapid release environments
Authors: Hemmati Hadi , Fang Zhihan , Mäntylä Mika V. , Adams Bram
Published: July 2016

Test case prioritization is an important testing activity, in practice, specially for large scale systems. The goal is to rank the existing test cases in a way that they detect faults as soon as possible, so that any partial execution of the test suite detects the maximum number of defects for the given budget. Test prioritization becomes even more important when the test execution is time consuming, for example, manual system tests versus automated unit tests. Most existing test case prioritization techniques are based on code coverage, which requires access to source code. However, manual testing is mainly performed in a black‐box manner (manual testers do not have access to the source code). Therefore, in this paper, the existing test case prioritization techniques (e.g. diversity‐based and history‐based techniques) are examined and modified to be applicable on manual black‐box system testing. An empirical study on four older releases of desktop Firefox showed that none of the techniques were strongly dominating the others in all releases. However, when nine more recent releases of desktop Firefox, where the development has been moved from a traditional to a more agile and rapid release environment, were studied, a very significant difference between the history‐based approach and its alternatives was observed. The higher effectiveness of the history‐based approach compared with alternatives also held on 28 additional rapid releases of other Firefox projects – mobile Firefox and tablet Firefox. The conclusion of the paper is that test cases in rapid release environments can be very effectively prioritized for execution, based on their historical failure knowledge. In particular, it is the recency of historical knowledge that explains its effectiveness in rapid release environments rather than other changes in the process. Copyright © 2016 John Wiley & Sons, Ltd.
The $$\upalpha +\upvarepsilon $$ Two-Phase Equilibrium in the Fe-N-C System: Experimental Investigations and Thermodynamic Calculations
Authors: Göhring HOLGER , Leineweber ANDREAS , Mittemeijer ERIC JAN
Published: July 2016

The present work is dedicated to investigating the occurrence of the

$$\upalpha +\upvarepsilon $$

α
+
ε

equilibrium at temperatures typically applied for nitrocarburizing treatments. To this end, pearlitic Fe-C specimens were treated between 823 K and 863 K (550 °C and 590 °C) in gaseous nitriding and gaseous nitrocarburizing atmospheres, allowing control of the chemical potentials of N and C. Subsequently, the resulting compound-layer microstructures were investigated using light microscopy and X-ray diffraction. Thermodynamic calculations, adopting several models for the Fe-N-C system from the literature, were performed, showing significantly different predictions for both the sequence of the invariant reactions and their temperatures. Comparison of the experimental data and the theoretical calculations led to the conclusion that none of the models from the literature is able to realistically describe the experimentally observed constitution in the Fe-N-C system in the considered temperature range. Values/value ranges for the temperatures of the invariant reactions were obtained.
Self-Inflicted Nailgun-Induced Penetrating Penile Injury: Case Report and Discussion
Authors: Hernandez Jeremy Mark , Hamilton David , Upadhye Suneel
Published: July 2016

Penetrating penile injuries occur mostly in industrial/work accidents, automobile accidents, or as a result of sexual curiosity and attempts at self-expression/mutilation. In this case report, the authors describe an accidental nailgun injury to the penis of a 46-year-old man. We discuss the management of such injuries in the emergency department, including the utility of a dorsal penile block for regional anesthesia. Although exceptionally rare, familiarity with penetrating lower urinary tract injuries may reduce their long-term repercussions on genitourinary and sexual health.
Fated to be Orphans: The Consequences of Australia's Post-War Resettlement Policy on Refugee Children
Authors: Agutter Karen
Published: July 2016

Between 1947 and 1953, Australia received over 170,000 Displaced People from Europe including widows and unmarried mothers. These refugees were expected to conform to the policies and expectations of the State, in particular the adherence to a 2-year work contract. This was an impossibility for many mothers who could not find work or accommodation outside of the government supplied migrant accommodation centres, and who, as a consequence, resorted to placing their children, either temporarily or permanently, in institutions or for adoption. Through an examination of archival documents, this paper examines the policies that resulted in migrant child placement and adoption and considers the role played by Department of Immigration social workers. It asks why, when migrant children were considered amongst the most desirable of new arrivals, were many fated to become orphans?
A Concise Set of Structure and Process Indicators to Assess and Compare Antimicrobial Stewardship Programs Among EU and US Hospitals: Results From a Multinational Expert Panel
Authors: Pollack Lori A. , Plachouras Diamantis , Sinkowitz-Cochran Ronda , Gruhler Heidi , Monnet Dominique L. , Weber J. Todd ,   Transatlantic Taskforce on Antimicrobial Resistance (TATFAR) Expert Panel on Stewardship Structure and Process Indicators
Published: July 2016

OBJECTIVES

To develop common indicators, relevant to both EU member states and the United States, that characterize and allow for meaningful comparison of antimicrobial stewardship programs among different countries and healthcare systems.

DESIGN

Modified Delphi process.

PARTICIPANTS

A multinational panel of 20 experts in antimicrobial stewardship.

METHODS

Potential indicators were rated on the perceived feasibility to implement and measure each indicator and clinical importance for optimizing appropriate antimicrobial prescribing.

RESULTS

The outcome was a set of 33 indicators developed to characterize the infrastructure and activities of hospital antimicrobial stewardship programs. Among them 17 indicators were considered essential to characterize an antimicrobial stewardship program and therefore were included in a core set of indicators. The remaining 16 indicators were considered optional indicators and included in a supplemental set.

CONCLUSIONS

The integration of these indicators in public health surveillance and special studies will lead to a better understanding of best practices in antimicrobial stewardship. Additionally, future studies can explore the association of hospital antimicrobial stewardship programs to antimicrobial use and resistance.

Infect Control Hosp Epidemiol 2016:1–11
Maladaptive Perfectionism, Acculturative Stress and Depression in Asian International University Students
Authors: Huang Shaun L. , Mussap Alexander J.
Published: July 2016

Despite the advantages of international study — to the student, the university, and the local community — studies have reported an increased risk of stress-related psychological problems in international students. We surveyed 384 Asian international students (189 female, 193 male, 2 undeclared; aged 17 to 47 years) attending Australian universities in order to examine whether depressive symptoms in these students are related to their trait maladaptive perfectionism and the extent to which they have experienced acculturative stress while in Australia. Path analyses suggest that maladaptive perfectionism influences depression indirectly by increasing acculturative stress (mediation model) and to a lesser extent by interacting positively with acculturative stress (moderation model). The results reveal ways in which maladaptive perfectionism can affect the wellbeing of Asian international students experiencing adjustment-related stress.
THE TEACHING AND PRACTICE OF FILIAL PIETY IN BUDDHISM
Authors: Xing Guang
Published: July 2016

Buddhist scholars like Kenneth Ch'en have argued that the teaching of filial piety was a special feature of Chinese Buddhism as a response to the Chinese culture. Others, among them John Strong and Gregory Schopen, have shown that filial piety was also important in Indian Buddhism, but Strong does not consider it integral to the belief system and Schopen did not find evidence of it in early writings he examined. In this article, through an analysis of early Buddhist resources, the Nikāyas and Āgamas, I demonstrate that the practice of filial piety has been the chief good karma in the Buddhist moral teaching since its inception, although it is not as foundational for Buddhist ethics as it is for Confucian ethics. The Buddha advised people to honor parents as the Brahmā, the supreme god and the creator of human beings in Hinduism, as parents have done much for their children. Hence, Buddhism teaches its followers to pay their debts to parents by supporting and respecting them, actions that are considered the first of all meritorious deeds, or good karma, in Buddhist moral teachings. Moreover, according to the Buddhist teaching of karma, matricide and patricide are considered two of the five gravest bad deeds, and the consequence is immediate rebirth in hell. Mahāyāna Buddhism developed the idea of filial piety further and formulated the four debts to four groups of people—parents, sentient beings, rulers, and Buddhism—a teaching that became very popular in Chinese Buddhism and spread to other East Asian countries.
The Calculation of Potential Derivatives by Using NBIE for Anisotropic Potential Problems
Authors: Zhou H.-L. , Bian B.-X. , Tian Y. , Yu B. , Niu Z.-R.
Published: July 2016

The natural boundary integral equation (NBIE) is developed to calculate potential derivatives for potential problems with anisotropic media. Firstly, the governing equation of the two-dimensional anisotropic potential problem is transformed into standard Laplace equation by a coordinate transformation method. Then a potential derivative boundary integral equation named as NBIE is extended to solve the anisotropic potential problem. The most important virtue of the NBIE is that the singularity of the integral kernel function is reduced by one order in comparison with the conventional potential derivative boundary integral equation(CDBIE). Therefore the new potential derivative boundary integral equation only contains strongly singular integrals rather than hyper-singular integrals. Thus the NBIE can calculate more accurate potential derivative results for both boundary nodes and interior points. Moreover, in combination with the analytical integral regularization algorithm of nearly singular integrals, the NBIE can obtain more accurate potential derivatives of interior points very close to the boundary than the CDBIE. Numerical examples on heat conduction in anisotropic media demonstrate the accuracy and efficiency of the NBIE.
A note on subsonic aerofoil theory
Authors: Miles John W.
Published: July 2016

A linearised theory for the subsonic, lifting surface problem is formulated in terms of Fourier integral solutions to Laplace’s equation. The symmetric and anti-symmetric problems of the first kind are solved explicitly, while the problems of the second kind depend on the solution of dual integral equations. The antisymmetric problem of the second kind is cast in a variational form, from which certain well-known theorems may be deduced.
Supersonic Flow Past Bodies of Revolution with Thin Wings of Small Aspect Ratio
Authors: Stocker P. M.
Published: July 2016

The method developed by G. N. Ward for the treatment of slender pointed bodies in a uniform supersonic stream is applied to three special cases.

(i)

Supersonic flow past a body of revolution with thin wings of symmetrical section and of small aspect ratio at zero incidence.

(ii)

Supersonic flow past a body of revolution with plane wings of small aspect ratio set at incidence to the body, the whole being at incidence to the stream.

(iii)

Supersonic flow past a body of revolution with a plane fin of small aspect ratio set at incidence, the whole being at incidence to the stream.

The pressure distribution on the wing has been calculated for a special case of (i) and is given in the Appendix.
A New Approach to Thin Aerofoil Theory
Authors: Lighthill M.J.
Published: July 2016

The general technique for rendering approximate solutions to physical problems uniformly valid is here applied to the simplest form of the problem of correcting the theory of thin wings near a rounded leading edge. The flow investigated is two-dimensional, irrotational and incompressible, and therefore the results do not materially add to our already extensive knowledge of this subject, but the method, which is here satisfactorily checked against this knowledge, shows promise of extension to three-dimensional, and compressible, flow problems.

The conclusion, in the problem studied here, is that the velocity field obtained by a straightforward expansion in powers of the disturbances, up to and including either the first or the second power, with coefficients functions of co-ordinates such that the leading edge is at the origin and the aerofoil chord is one of the axes, may be rendered a valid first approximation near the leading edge, as well as a valid first or second approximation away from it, if the whole field is shifted downstream parallel to the chord for a distance of half the leading edge radius of curvature ρL. It follows that the fluid speed on the aerofoil surface, as given on such a straightforward second approximation as a function of distance x along the chord, similarly is rendered uniformly valid (see equation (52)) if the part singular like x-1 is subtracted and the remainder is multiplied by .
Supersonic Flow over Thin Symmetrical Wings with Given Surface Pressure Distribution
Authors: Goldsworthy F. A.
Published: July 2016

The inverse problem of determining the supersonic flow past a thin symmetrical wing at zero incidence with given surface pressure distribution is solved for wings of arbitrary plan form. Expressions are obtained for the vertical derivative of the potential on the wing surface from which, using the linearised boundary condition of zero normal velocity at the surface, the profile of the wing can be designed. The integral equation method adopted by J. C. Evvard and extended by G. N. Ward is used. The analysis cannot be applied to pointed wings, whose leading edges are subsonic. The results in Part I are completely general and are applied to specific problems in Part II.
A note on the performance of ducted fans
Authors: Thwaites Bryan
Published: July 2016

The strip-theory equations of flow through a ducted fan were the basis of a method of designing a fan for a given performance. The merit of the method was that it amounted to an explicit solution of the design problem, no iteration being necessary.

In the inverse problem, of determining the flow past a given fan in conditions other than those of the design, two relations—the motor or tunnel characteristics, for example—will be given between the four quantities P, Ω, η, u (the motor power and angular velocity, the fan efficiency and the air speed at the fan). The problem is to determine the values of these four quantities together with details of the flow past any blade element.

This paper shows that to a high degree of accuracy the performance of a ducted fan can be summed up by saying that P/Ω3 and η are both functions of Ω/u only, functions which depend only on the fan shape. Solution by graphical means is therefore almost instantaneous.

The fan-tunnel combination is shown to be governed by extremely simple equations which amount to saying that the tunnel power factor is a function of Ω/u only which, again, can be calculated once for all for a given fan and tunnel.
Photoelastic Investigation on Plates with Single Interference-Fit Pins with Load Applied (a) to Pin only and (b) to Pin and Plate Simultaneously
Authors: Jessop H. T. , Snell C. , Holister G. S.
Published: July 2016

The reduction in stress concentration factors resulting from the introduction of an interference-fit pin in a circular hole in a flat plate to which a simple tension is applied has already been recorded. The same result is found to occur to an equally marked extent, and qualitatively in a very similar way, when the load is applied to the pin itself. When varying loads are applied to the pin or the plate, the effect of the interference is to produce a rise in the mean stress level at critical points on the hole boundary with a marked fall in the oscillatory stress. There appears to be an optimum value for the “interference stress” for given applied loading conditions at which the endurance of the plate will have its highest value.

When loads are applied simultaneously to pin and plate the critical stress on the hole boundary is found to be the mean of the stresses which would be produced by the total load applied separately to the pin and to the plate.
Graphite: A Future Structural Material
Authors: Kennedy A. J.
Published: July 2016

Graphite is a material with unique high-temperature properties. Its strength and modulus increase with temperature up to about 2000-2500°C., in which range it exhibits a higher strength than any known material. The development of new types of graphite (such as pyrolytic graphite, deposited from the vapour) and impregnated graphites, are both significant to future technology. The highly-oriented pyrolytic graphites in particular, with their marked thermal and mechanical anisotropy, and their superior mechanical properties (60 x 103lb./in.2strength at 2750°C, with 60 per cent ductility) offer distinct possibilities, particularly in composite structures. Graphite sublimes directly from the solid to vapour phase at 3700°C. at atmospheric pressure. As the sublimation energy is high, it is, at least in theory, a very efficient ablating material. It also has a high creep resistance. Surface reactions limit its value, particularly in oxidising environments, and coatings, or other methods of surface protection, are of high importance. The modulus of graphite is low, being about one-half of that for lead at room temperature, increasing with temperature to a maximum in the region of 2200°C. The properties vary in detail from one type of graphite to another, and with the direction in which measurements are made. Graphite has a low density (about 2·0) and is comparatively cheap, so that its low temperature limitations (zero ductility at room temperature) may be offset, at least in part, by a re-appraisal of the design factors. It can be joined and fabricated fairly readily, and appears to be a material of great value to advanced high-temperature projects in the future, where composite assemblies of various kinds will be essential.
The Vibration of Air in a Duct with a Subsonic Mean Flow
Authors: Whitehead D. S.
Published: July 2016

The effect of a subsonic mean flow on the organ-pipe type of vibration of the air in a duct of uniform area is calculated. The flow at entry to the duct is assumed to be at constant stagnation pressure, and a range of exit conditions is considered. It is found that the effect of the mean flow is to reduce the resonant frequencies by a factor of (1—M2) (where M is the Mach number in the duct) and to introduce damping of the vibration. Except when the duct is terminated by an efficient diffuser, this damping is rather large and it would require a powerful driving mechanism to produce large vibrations in the duct.
The Elastic Stress Concentration Factors in Shouldered Shafts
Authors: Allison I. M.
Published: July 2016

This paper, which describes a photoelastic determination of the elastic stress concentration factors associated with shouldered shafts subjected to pure bending, forms the second part of an investigation initiated by the Structures Committee of the Royal Aeronautical Society. A general description of the manufacture of the models, the photoelastic technique employed to evaluate the s.c.f. and the results of the tests on shouldered shafts subjected to torsion have been given in Part I (Ref. 1).
On the Interpretation of the Vector Plots of Forced Vibrations of a Linear System with Viscous Damping
Authors: Woodcock D. L.
Published: July 2016

A new method of analysing the response of linear systems to sinusoidal excitation, which avoids the assumptions of present methods, is developed in this paper. It enables one to obtain the eigenvalues and righthand eigenvectors of a system with viscous damping from the response of the system. If the inertia matrix of the system is known, the damping and stiffness matrices can also be obtained. No assumptions are made about the form of these matrices, and the method is not restricted to systems with only small amounts of damping.
The Effect of Lumped Parameters on Beam Frequencies
Authors: Leckie F. A. , Lindberg G.M.
Published: July 2016

An investigation has been made into the errors involved in using certain lumped parameter methods for the solution of beam frequencies. It is found that existing methods are not consistent for all boundary conditions. A new dynamic stiffness matrix has been formulated, which gives consistently good results for even a few elements. The error in the solution is always inversely proportional to the fourth power of the number of elements used.
Aerodynamic and Thermodynamic Effects of Coolant Injection on Axial Compressors
Authors: Hill P. G.
Published: July 2016

A study has been made of the effects of inlet coolant injection upon axial compressor performance, using the results of tests on turboshaft engines. It is shown that evaporation of the coolant changes the stage work distribution as well as the ideal compression work and that these effects may be estimated by elementary thermodynamic methods. Simplified prediction procedures are suggested and compared with experimental results.
Note on the Speed of Stall Propagation in a Cascade of Aerofoils
Authors: Cheers F. , Funnell G. C.
Published: July 2016

From an investigation of published experimental results, it appears that three types of propagating stall cells occur on isolated blade rows. On stationary blade rows, and rotating rows which have the highest blade incidence at the tip, the speed of propagation seems to depend on a parameter based on the blade section near the leading edge, and in some experiments marked changes in this speed have been observed to coincide with changes in the form of stall on the individual blades. For rotating rows with the highest incidence at root or mid-section the speed of stall propagation lies within a fairly limited range and shows no dependence on the blade geometry. When the incidence is increased well beyond that at which stall first occurs, the stall cell pattern on most rotating rows changes from multiple cells to one or two of very large amplitude, with a marked change in speed of propagation.
The Turbulent Supersonic Base Pressure Problem: A Comparison between a Theory and Some Experimental Evidence
Authors: McDonald H.
Published: July 2016

A comparative study is made of a recent theoretical approach to the problem of predicting the supersonic, turbulent base pressure and of the experimental evidence. The theory is based on the Chapman-Korst flow model of separated flows with a modified recompression process. Due allowance can be made for the presence of the initial boundary layer, with the limitation that its thickness must be less than about one step height at low Mach numbers, dropping to about one third of a step height at M=3·0. Fairly good agreement between the predicted and measured base pressure can be obtained although a predicted Reynolds number effect is not observed. The absence of this Reynolds number effect is. discussed in the light of recent experiments on flow mixing.
The Dynamic Response of Structural Members. An Improvement in Classical Methodology
Authors: Pilkey W. D.
Published: July 2016

It is shown that considerable improvement is achieved in the most popular classical approach to the vibration of structural members by giving new meaning to the generalised coordinate term in the infinite series expansion of the product of the generalised coordinate and eigenfunction. A transform employing the eigenfunction as a kernel efficiently generates a universal solution that embraces arbitrary loading, time-dependent boundary conditions, and such in-span conditions as supports and changes in cross section, axial load, and elastic foundation modulus. The method is applied to the Timoshenko beam as a representative structural member.
Calculated Pressure Distributions and Shock Shapes on Thick Conical Wings at High Supersonic Speeds
Authors: Squire L. C.
Published: July 2016

In recent papers Messiter and Hida have proposed a first-order correction to simple Newtonian theory for the pressure distributions on the lower surfaces of lifting conical bodies with detached shocks. The method involves the solution of an integral equation which Messiter solved numerically for thin delta wings, while Hida gave an approximate solution for thick wings with diamond and bi-convex cross-sections. It is shown in the present paper that Hida’s approximate solutions give poor agreement with experiment, and a series of more precise numerical solutions of the equation are given for wings with diamond cross-sections. The pressures, and shock shapes, obtained from these solutions are in very good agreement with experiment at Mach numbers as low as 4·0.

The method has also been extended to Nonweiler wings at off-design when the shock wave is detached from the leading edges. Again the agreement with experiment is good provided the integral equation is solved numerically.
Application of the Discrete Element Method to the Buckling Analysis of Rectangular Plates under Arbitrary Membrane Loading
Authors: Dawe D. J.
Published: July 2016

The discrete element displacement method is used to analyse the instability of flat rectangular plates subjected to arbitrary systems of in-plane loading. Critical load intensities calculated in a range of applications, some of which include discrete reinforcing members, are compared with the predictions of past investigators and demonstrate the accuracy of the procedure.
Attitude Dynamics and Stability Conditions of a Non-Rigid Spinning Satellite
Authors: Rossi L. C. , Di San Martino R. C. Michelini , Ghigliazza R.
Published: July 2016

The attitude dynamics of a spinning satellite containing an elastically-restrained, viscously-damped mass, is investigated. This non-rigidity approximately represents the interesting practical case of equipment supported by relatively soft anti-shock mountings and the case of a particular viscous nutation damper. The linearised differential equations and the transfer functions relating the dynamic behaviour of the oscillating mass to the spinning-body components of the angular speed and the external torque are determined. On these grounds, the possibility of unstable configurations is singled out and discussed, and the stability condition is established, within the small perturbation approximations. Furthermore, the attitude dynamics for the satellite, both for large manoeuvres and fine corrections, is obtained by applying a train of pulsed torques by means of a suitable control logic and mass-ejection jets. The results are compared with those obtained from rigid-body theory. It is demonstrated that comparatively wide nutations may be produced, and the influence of the relevant parameters is determined.
An Unsteady Flow Wind Tunnel
Authors: Horlock J H
Published: July 2016

A novel low-speed wind tunnel which produces unsteady “gust” flows is described. The walls are sinusoidal in shape and are moved in the flow direction with a velocity Wwless than the mean velocity Wmof the free stream. The tunnel is useful for testing isolated aerofoils and aerofoils in cascade in non-convective gusts (Ww< Wm) so that comparisons with predictions by thin aerofoil theory may be made. However, it does not simulate precisely the unsteady flow that occurs in axial flow turbomachines.
Generation of Weak Shock Waves in a Shock Tube
Authors: Dain C G , Hodgson J P
Published: July 2016

The properties of weak shock waves in a vibrationally relaxing gas are discussed with particular application to waves in carbon dioxide. An account of various methods of generating weak shock waves in a shock tube is given. The best method requires the insertion of a perforated plate in the low pressure section of the shock tube. A suitable choice for the open-to-total area ratio of the plate leads to transmitted waves in the appropriate strength regime. These waves were observed using a Mach-Zehnder interferometer and were either fully or partly dispersed by vibrational relaxation. Values for the relaxation frequency of carbon dioxide at room temperature were obtained.
Viscous Modelling of Wing-Generated Trailing Vortices
Authors: Williams Geoffrey M
Published: July 2016

The trailing vortex wake system generated by a lifting wing of finite span is modelled with a pair of laminar, viscous vortex models of a new type. The embryonic form of this viscous wake model is matched, at several interior collocation points, to the inviscid Betz model of the wake convolution process that transforms the wing trailing-edge vortex sheet into a pair of axisymmetric trailing vortices. In the near-wake and intermediate-wake regions downstream of the wing, the viscous wake model indicates that the trailing vortex characteristics (particularly the peak swirl velocity and the circulation profile) are strongly influenced by details of the wing span load distribution. Using simple eddy viscosity concepts, the viscous wake model achieves good qualitative agreement with test results from a limited selection of published experimental wake investigations. The present laminar theory appears to offer a useful basis for developing an engineering prediction method of aeroplane wake characteristics.
Two-Dimensional Boat-Tailed Bases in Supersonic Flow
Authors: Viswanath P R , Narasimha R
Published: July 2016

Boat-tailing of aft bodies may affect the base pressure through two mechanisms: firstly by changing the angle between the approaching flow at separation and the reattachment surface, and secondly by distorting the boundary layer through the favourable pressure gradient (which can be particularly severe in the presence of a sharp corner on the body). The first effect is isolated here by tests on inclined backward-facing steps with a fully developed turbulent boundary layer at separation, at free-stream Mach numbers of 1.75 and 2.4. It is found that the base pressure increases significantly with boat-tail angle; the data have been correlated taking explicit account of the boundary layer effect, modifying and extending the approach adopted by Nash. Charts are provided for quick estimation of base pressure in engineering calculations. Some of the earlier data on boat-tailed bases, on re-examination in the light of the present correlation, suggest that strongly distorted boundary layers at separation affect the base pressure appreciably. Several features of the measured reattachment pressure distributions, including their internal similarity, are also discussed.
Numerical Solution of the Hypersonic Wake behind a Wedge
Authors: Walitt L , Liu C Y
Published: July 2016

A numerical method which solves the time-dependent Navier-Stokes equations for plane, two-dimensional, compressible flow problems is presented. The method was applied to obtain the steady-state flow field about a flat-based 20° wedge at a free-stream Mach number of 6.05, a free-stream Reynolds number (based on the base height of the wedge) of 1.41 × 104, and a Prandtl number of 0.75. Two wedge surface temperature boundary conditions were investigated: adiabatic and isothermal walls. Convergence of the numerical solutions was demonstrated using two different finite-difference meshes. Numerical errors in the static pressure, velocity, and static temperature were generally less than 8 per cent in the wake of the body. Comparisons with experimental results and other independent theories were also made. For the isothermal wedge, calculated pressures on the surface of the body (including its base), static pressure profiles, pitot pressures profiles, and velocity profiles in the near wake were in agreement with corresponding experimental data. A comparison of static temperature profiles in the near wake of the isothermal wedge produced significant differences between numerical and experimental results near the wake shock. It was found that these differences could be explained in terms of uncertainties in the accuracy of the experimental measurements and thermal boundary conditions on the wedge surface. For the adiabatic wedge, the ramp boundary layer profiles and pressure distribution were in agreement with theoretical predictions coming from hypersonic interaction theory.
Turbulent Boundary Layer with Pressure Gradient Alternating in Sign
Authors: Tsuji Yutaka , Morikawa Yoshinobu
Published: July 2016

An experiment was made on a turbulent boundary layer with adverse and favourable pressure gradients alternating twice along the stream. The most important findings of the present study are as follows. In the region of the adverse pressure gradient downstream of the strong acceleration, an internal boundary layer develops within the boundary layer. In this internal layer large advection of turbulent energy occurs and the flow is locally non-equilibrium even near the wall. As a result the usual logarithmic law and turbulence similarity in the viscous sublayer break down.
A Theoretical Study of Body Drag in Subcritical Axisymmetric Flow
Authors: Myring D F
Published: July 2016

A method of predicting body drag in subcritical axisymmetric flow is outlined which requires only detailed body shape, free-stream conditions and transition point to be prescribed. Results of calculations for a range of body shapes are shown essentially to confirm information in Royal Aeronautical Society Data Sheets but clearly demonstrate that fineness ratio alone is not sufficient to characterise body shape. For example, at a fixed fineness ratio of 0.18, detailed changes in body contour are shown to produce 10 per cent changes in drag coefficient.
Local Buckling of Outstands in Stiffened Plates
Authors: Fok W C , Rhodes J , Walker A C
Published: July 2016

This paper reports on an investigation of the effect of local elastic buckling of stiffener outstands on the overall behaviour of stiffened plates. A simplified mathematical model has been developed, based on the post-buckling analysis of the stiffener, and gives a simple expression which indicates that, for the plate geometry investigated, the maximum load carried varies asymptotically between the local critical load of the stiffener and a reduced Euler load. Also, there is a marked imperfection sensitivity arising from the interaction of the local and overall buckling modes. Experiments were carried out to confirm the analytical prediction for the elastic buckling behaviour of the stiffened plates. The models were constructed of Araldite, to allow large deformation within the elastic strain range. Experimental results showed very good agreement with the theory.
The Axisymmetric Impingement of Supersonic Air Jets on Cones
Authors: Jennions I.K. , Hunt B.L.
Published: July 2016

This paper reports an experimental investigation into the impingement of three jets from a convergent, conically divergent nozzle on to three cones of apex angles 120°, 90° and 60°. The exit Mach number of the nozzle was 2.2 and the jets were produced by operating with ratios of nozzle lip pressure to ambient pressure of 1, 1.2 and 2. The cones were arranged symmetrically in the jets at nozzle to apex distances of 0, 1 and 2 times the nozzle exit diameter. Surface pressures and shadowgraph pictures are presented. The most striking feature of the flows is the shock pattern produced by the interaction between the cone shock and the jet shock. This pattern can take a wide variety of forms depending on the structure of the free jet and strongly influences the form of the surface pressure distribution. For the most part, the flows can be explained on the basis of inviscid behaviour.
Part II: Spanwise Correlation and Loading
Authors: Wilkinson R.H.
Published: July 2016

The influence of spanwise correlation of fluctuating pressures due to vortex shedding on the total oscillatory loading of a long bluff cylinder in cross-flow is considered. Experimentally determined pressure correlation lengths on a stationary and vibrating cylinder of square cross section are then combined with previously obtained chordwise pressure distributions to demonstrate the amplification of the oscillatory lift on a long bluff cylinder during cross-flow vibrations.
The Aerodynamic Characteristics of D-Section Prisms in a Smooth and in a Turbulent Flow
Authors: Nakamura Y. , Tomonari Y.
Published: July 2016

A measurement of the pressure distributions on D-section prisms over wide ranges of depth to height ratio and incidence in a smooth and in a turbulent flow was made with particular reference to the onset of transverse galloping. Good correlation between the onset of galloping and the critical depth, established already for rectangular and the related prisms with sharp downstream corners, applied also to D-section prisms both in a smooth and in a turbulent flow. The development of a reattachment type pressure distribution on the side face of the prism as the critical depth is reached is responsible for this correlation. There is very little effect of turbulence on the pressure distribution and the Strouhal number of a D-section prism with a depth to height ratio of 0.5.
Non-Linear Stress-Strain Effects in the Flexural Wrinkling of Carbon Fibre Honeycomb Sandwich Beams
Authors: Ditcher A.K. , Webber J.P.H.
Published: July 2016

A theoretical analysis of the flexural wrinkling of a honeycomb sandwich beam with laminated faces having non-linear stress-strain behaviour is presented. Appropriate tangent moduli are used in the constitutive equations for the compression face and a double iteration technique is used to calculate wrinkling loads. Numerical results are given for sandwich beams with unidirectional and cross-ply carbon fibre reinforced plastic (CFRP) faces. Experimental failure loads of sandwich beams are compared with theoretical predictions, and, in general, the agreement between the two is good.
On the Torsional Modes of a Uniformly Tapered Solid Wing
Authors: Mansfield E.H.
Published: July 2016

An exact analysis is first given, within the spirit of elementary theory, of the torsional modes of a uniformly tapered solid wing whose section shape - as distinct from size - is constant. Numerical results are presented for the first five torsional modes for various values of tip chord/root chord. It is shown that the frequencies are fairly insensitive to the magnitude of the taper and a corollary to this, which is also investigated, is that an analysis based on a partially stepped representation of the taper yields close estimates of the frequencies but can yield massive differences in the higher mode shapes. An analysis is also made of warping restraint and distributed inertia effects.
Calculation of Potential Flow about Arbitrary Three Dimensional Wings using Internal Singularity Distributions
Authors: Singh N. , Bandyopadhyay G. , Basu B.C.
Published: July 2016

A first order panel method has been developed for calculating the incompressible potential flow about arbitrary three-dimensional wings. The method utilises a distribution of source and vorticity singularities on the mean camber surface of the wing and solves for the distribution by satisfying the boundary condition of zero normal flow at selected points on the surface of the wing. The method takes less computing time compared to other existing first order methods for the comparable numerical accuracy. This method can handle wings having cusped trailing edges and thin sections.
Some Properties of Nodes in Vibrating Systems
Authors: Bishop R. E. D. , Johnson D. C.
Published: July 2016

Special forms of the receptance functions of mechanical systems are shown to indicate the existence of nodes. these are associated with horizontal straight lines in receptance diagrams. the effects of this nodal condition are explained in terms of simple torsional and translational systems for the sake of simplicity; but the theory may be extended to any type of system and any set of generalised co-ordinates. a particular instance arises if principal co-ordinates are used. the paper is a sequel to an earlier paper.
Non-Linear Elasticity in Aluminium Alloys
Authors: Watts A. B.
Published: July 2016

Tests have been carried out on round bar specimens of various strong aluminium alloys (unclad) in the fully heat-treated condition in both tensile and compressive loading. A careful study of the results establishes beyond reasonable doubt that there is a progressive change in the tangent elastic modulus with stress. The variation is appreciably greater than that predicted by the consideration of second-order effects in the conventional stress and strain representation. It is found that the modulus decreases with tension and increases with compression by about 5 per cent at 30 tons/in.2, the form of the variation being a continuous function. Tests on two alloys of aluminium other than those of the normal zinc-bearing and the copper-bearing types were also carried out. The first of these was a simple fully heat-treated binary alloy of 4 per cent copper which was very similar in behaviour to D.T.D.364; the second was a 5 per cent alloy (N.S.6-½H) which, after its initial loading, showed only very slight elastic modulus variation in the subsequent loading and unloading lines. An additional test to compare naturally and artificially aged D.T.D.364 did not reveal any difference in the degree of modulus variation.

In view of the present experimental findings, the use of the “second” modulus line in the proof stress determination of unclad strong alloys should be adopted generally, if practicable. A high level of internal stress can cause slight errors in this method because the elastic limit is then prematurely reached. As an occasional check on the method when applied to routine mechanical testing, the elastic component of strain can be found for the last point on the loading line by returning to the zeroing load.

In the Appendix the difference between true and nominal stress-strain relationships is calculated. The meaning and theory of modulus variation is also discussed and aluminium alloys are compared with a high-tensile steel.

A simple expression for the form of the variation is proposed.
The Influence of the Wake on the Flutter and Vibration of Rotor
Blades
Authors: Jones J. P.
Published: July 2016

An approximate theory is described which takes into account the
influence of the wake on the aerodynamic derivatives of an oscillating rotor
blade. It is shown that the most important parameter is the number of cycles
of the oscillation which occur during one revolution of the rotor. For
integral values of this parameter the flexural damping is shown to become
very small at small angles of incidence. The flutter characteristics of a
simple rotor blade are calculated on the basis of this theory, and it is
found that the wake causes radical changes in the critical speeds. The
theory is in good qualitative agreement with experiment.
The Buckling of a Rectangular Plate under Combined Biaxial Compression, Bending and Shear
Authors: McKenzie K. I.
Published: July 2016

An analysis is presented of the buckling of a rectangular plate under combined biaxial compression, bending and shear. The sides of the plate to which bending is applied are simply-supported, the other two sides being supported by arbitrary edge members. The solution is expressed in a form suited to automatic computation and some sample results are given.