bluuebunny/crossref_metadata_2025_split huggingface dataset:
Majoring in nutrition influences BMI of female college students
Authors: Hong Mee Young , Shepanski Tahirih L. , Gaylis Jaclyn B. 
Published: February 2016

AbstractMaintaining healthy eating habits in college is challenging. Interventions focused on nutrition education can assist in reversing these trends of poor eating habits among college students. The purpose of the study was to identify factors affecting the dietary habits, food choices and BMI of college females majoring in nutrition (NMs) compared with non-nutrition majors (OMs). A questionnaire-based cross-sectional survey study of dietary behaviour and food frequency of 202 college females was conducted at San Diego State University. Data were analysed by using t tests, χ2 tests and regression analysis in SPSS. NMs exhibited a lower BMI than OMs (P < 0·01); however, BMI values for both groups were within a healthy range. Interestingly, 3 % of NMs had a BMI in the range of overweight or obese; however, prevalence was three times higher for OMs, being 9·2 %. A healthier meal option was the most influential factor in NMs’ meal choices whereas convenience and weight control were influential factors in OMs’ meal choices. Most NMs read nutrition labels and reported that this affects their food choices. NMs exercised longer than OMs in the <120 min/week category. Exercise affected healthy meal conception in NMs only (P < 0·001). Taking dietary supplements influenced healthy meal awareness in OMs only (P < 0·05). University-level nutrition education is strongly associated with healthier eating habits and superior food choices among young adult females. More regular meal patterns, healthier snack choice and adherence to dietary guidelines may contribute to the lower BMI values observed among NMs compared with OMs.
Some Recent Developments in the Landing Gear Field
Authors: Lucien Rene 
Published: February 2016

What are the particular factors of the aeroplane of 1947, which have a special effect on landing gear technique?(i)Increase in the speed of take-off and landing.1940: 65 to 90 m.p.h.1947: up to 130 m.p.h.(ii)Increase in wing loading and the use of thin or laminar flow wing sections.1940: 301b. sq.ft.1947: more than 50 lb. sq. ft.(iii)Increase in physical dimensions and all-up-weight of the aircraft.1940: 80,000 lb.1947: 300,000 1b.(iv)Increase in operational altitude.1940: 10,000 to 15,000 ft.1947: 15,000 to 30,000 ft.
Heliplat®: high altitude very-long endurance solar powered UAV for telecommunication and Earth observation applications
Authors: Romeo G. , Frulla G. 
Published: February 2016

AbstractResearch is at present being carried out at the Turin Polytechnic University with the aim of designing an HAVE/UAV (high altitude very-long endurance/unmanned air vehicle). The vehicle should climb to 17-20km by mainly taking advantage of direct Sun radiation and thereafter maintain a level flight; during the night, a fuel cells energy storage system would be used. A computer program has been developed to carry out a parametric study for the platform design. The solar radiation change over one year, the altitude, masses and efficiencies of the solar and fuel cells, and the aerodynamic performances have all been taken into account. The parametric studies have shown how fuel cells and solar cells efficiency and mass have the most influence on the platform dimensions. A wide use of high modulus CFRP has been made in designing the structure in order to minimise the airframe weight. A first configuration of HELIPLAT® (HELIos PLATform) was worked out, following a preliminary parametric study. The platform is a monoplane with eight brushless electric motors, a twin-boom tail type with an oversized horizontal stabiliser and two rudders. The co-ordinates at the root and along the wing span as well as the wing planform were optimised to achieve the best efficiency. Several profiles and wing plans have been analysed using the CFD software Xfoil and Vsaero. Several wind-tunnel tests were carried out to compare the analytically predicted performances. A preliminary design of a scale-sized technological demonstrator was completed with the aim of manufacturing a proof-of-concept structure. A FEM analysis was carried by using the Msc/Patran/Nastran code to predict the static and dynamic behaviour of the UAV structure.
A novel method for the provision of flight experience and flight testing for undergraduate aeronautical engineers at the University of Strathclyde
Authors: Stickland M. T. , Scanlon T. J. 
Published: February 2016

AbstractThe Department of Mechanical Engineering at the University of Strathclyde has developed a novel flight experience/test course for undergraduate Aeronautical Engineers. In common with similar courses at undergraduate level the course contains practical instruction in how an aircraft is flown, an analysis of its stall characteristics and an assessment of an aircraft’s performance and stability. However, uniquely, the Strathclyde course consists of dual instructional flights in two seat gliders. This paper contains a detailed description of the flight experience/test course developed at Strathclyde and its incorporation into the undergraduate curriculum. A critical analysis of its delivery is also presented.
Recent developments in delta wing aerodynamics
Authors: Gursul I. 
Published: February 2016

AbstractRecent developments in delta wing aerodynamics are reviewed. For slender delta wings, recent investigations shed more light on the unsteady aspects of shear-layer structure, vortex core, breakdown and its instabilities. For nonslender delta wings, substantial differences in the structure of vortical flow and breakdown may exist. Vortex interactions are generic to both slender and nonslender wings. Various unsteady flow phenomena may cause buffeting of wings and fins, however, vortex breakdown, vortex shedding, and shear layer reattachment are the most dominant sources. Dynamic response of vortex breakdown over delta wings in unsteady flows can be characterised by large time lags and hysteresis, whose physical mechanisms need further studies. Unusual flow–structure interactions for nonslender wings in the form of self-excited roll oscillations have been observed. Recent experiments showed that substantial lift enhancement is possible on a flexible delta wing.
Design methodology and performance of an indraft wind tunnel
Authors: Johl G. , Passmore M. , Render P. 
Published: February 2016

AbstractThe design methodology and performance of Loughborough University’s new 1·9m × 1·3m, indraft wind tunnel is discussed in the following paper. To overcome severe spatial and financial constraints, a novel configuration was employed, with the inlet and exit placed adjacent to each other and opened to atmosphere. Using a fine filter mesh, honeycomb, two turbulence reduction screens and a contraction ratio of 7·3, flow uniformity in the working area of the jet at 40ms-1is shown to be within 0·3% deviation from the mean velocity, with turbulence intensity in the region of 0·15%. Working section boundary layer characteristics are shown to be consistent with that of a turbulent boundary layer growing along a flat plate, which originates at the point of inflection of the contraction. A maximum velocity of 46ms-1was achieved from a 140kW motor, compared to a prediction of 44ms-1, giving an energy ratio of 1·42. Comparison between theoretical and measured performance metrics indicate differences between the way modules perform when part of a wind tunnel system compared to data gathered from test rigs.
Optimising expansion deflection nozzles for vacuum thrust
Authors: Taylor N. V. , Hempsell C. M. 
Published: February 2016

AbstractWhile expansion deflection (ED) nozzles have traditionally been considered primarily for use as altitude compensating devices to improve the performance of single stage to orbit vehicles, they also offer the potential for enhancing high altitude propulsion systems. If intended to only operate in near vacuum conditions, the complexity of analysis and inherent risks involved in the ED concept are greatly reduced. An integrated approach to the design and performance analysis of such nozzles is presented, comprising a mixture of computational fluid dynamics, the method of characteristics, and a semi-empirical model to allow full analysis of the closed wake flow-field of an ED nozzle. While it is demonstrated that the influence of the parameters used to define the throat region is critical to the successful application of the ED nozzle, it is also shown that with careful design the weight savings possible are significant. The analysis method itself is flexible and rapid, and lends itself well to incremental improvements in accuracy as the flow under consideration becomes better understood.
Life before and after implementation of an acoustic noise reduction enclosure
Authors: Timmins B. 
Published: February 2016

AbstractThis paper looks back on the designs and ambitions of ARA in resolving a long term acoustic noise problem which threatened ARA with closure. This paper today briefly looks back to the original issues but deals more fully with the later phases of a two phase project implementation and construction. ARA is now a truly ‘silent site’, where closure was once threatened, ARA has achieved the implementation of a bespoke noise reduction enclosure where 24-hour running has proved to be a reality. This paper looks at the design and construction phases, the ‘before and after’ noise footprints and at some of the financial benefits ARA has achieved.The ARA transonic wind tunnel is sited on an industrial estate on the north west perimeter of Bedford. When it was first built it was on an original farm site with no appreciable residential houses in close proximity. Since the early 1950s there has been considerable residential development around the ARA site resulting in the local householders complaining about the wind tunnel acoustic noise. In early 1999 ARA was obliged to consider several options for noise reduction measures to reduce the noise to within UK government statutory requirements.This paper deals briefly with the original noise nuisance characteristics and footprint, the noise reduction design and method that ARA selected and shows the construction phases, the further noise treatment ARA had to do on other major ancillary equipment to make ARA a truly quiet industrial site.The paper shows how ARA has utilised the resulting benefits of these investments to increase productivity and reduce costs, and the influence it has had on ARA’s financial health.
Infra-red signature reduction study on a small-scale jet engine
Authors: Dix J. , Saddington A.J. , Knowles K. , Richardson M.A. 
Published: February 2016

AbstractThis paper presents infra-red signature data for a small-scale, low pressure ratio turbojet engine typical of that used in unmanned air vehicle applications. The aim of the study was to test a number of different convergent nozzle designs concentrating on those with trailing edge modifications. The engine used in the tests has a single stage centrifugal compressor and radial inflow turbine and is designed to produce approximately 150N of thrust at 103,500rpm using liquid propane fuel. The test rig consisted of a calibrated thrust stand whilst the engine was controlled through an electronic engine control unit and laptop PC. The jet plume was visualised using an infra-red spectroradiometer which yielded qualitative data across the infra-red spectrum. Simultaneous measurements were also made of the engine thrust. A Pitot probe was used to take pressure readings across different sections of the exhaust flow. Analysis of the infrared signature of the engine exhaust plume and any thrust penalty yielded a performance comparison for each of the nozzles tested. Correlation of engine thrust with engine rpm showed that, within the accuracy of the measurements, there was no significant thrust penalty associated with the notched nozzles. Infra-red imagery of the plain and 60° notched nozzles indicated that the latter reduced the length of the hottest part of the exhaust plume by approximately 33%. The spectroradiometer data shows a significant reduction in spectral radiance for the CO2wavelength of approximately 4·3µm when the notched nozzles are used. The 60° notched nozzle appeared to perform best in reducing the spectral radiance at this wavelength. Centreline total pressure measurements in the exhaust plume correlated well with the infra-red imagery in that a potential core length reduction of up to 30% could be achieved using the 60° notched nozzle. Total pressure contours recorded 20mm (0·43D) downstream of the nozzle exit plane suggest that the notched nozzles are promoting increased mixing through radial spreading of the jet possibly associated with increased streamwise vorticity (although the latter could not be confirmed). There were also signs that the jet plumes being investigated were swirling.
The birth of the practical aeroplane: An appraisal of the Wright brothers’ achievements in 1905
Authors: Padfield G. D. , Lawrence B. 
Published: February 2016

AbstractIn this second Aeronautical Journal paper providing a technical appraisal of the Wright brothers’ achievements, the authors use modelling and simulation and associated flight dynamics analysis to present the development of the first practical aeroplane. The aircraft in question, the Wright Flyer III, was deemed fit for service by the Wrights in October 1905, and had evolved significantly from the first powered aircraft of 17 December 1903. The appraisal tries to shed light on many of the flight handling problems that the Wright brothers faced during this, their third phase of aeronautical endeavour, in 1904 and 1905. They retained their unstable configuration born in the 1901 and 1902 gliders, gradually refining the performance and handling until they considered the aircraft was ready for market. Their process of refinement has been reconstructed in simulation within the Liverpool Wright project, highlighting the many important developments during a period when Wilbur and Orville’s own documentation was limited. Apart from their engineering excellence, the Wright brothers are to be acknowledged for their perseverance and resolve in overcoming setbacks, for their ability to innovate and to recover and learn from their mistakes. In many ways the Wright brothers represent a model for the modern aeronautical engineer, and it is hoped that their legacy will be better preserved through the documentation of this project.
Prediction of acoustic resonance phenomena for weapon bays using detached eddy simulation
Authors: Ashworth R. M. 
Published: February 2016

AbstractIt is argued that acoustic resonance phenomena in open cavities such as weapons bays cannot be adequately predicted through numerical solution of Reynolds averaged Navier-Stokes (RANS) equations. The requirement to resolve the growth of the shear layer instability from the lip of the cavity inevitably implies that turbulence further downstream is resolved while also being modelled thus making RANS over dissipative. Large eddy simulation (LES) models only unresolved scales and a hybrid method combining RANS near walls with LES in the cavity appears a practical alternative to pure RANS. This paper compares computations of the M219 cavity configuration made with unsteady RANS and with the hybrid method known as detached eddy simulation (DES). It is shown that whilst unsteady RANS and DES give very similar predictions for the 1st and 3rd modes of the acoustic resonance the 2nd mode (which is dominant near the centre of the cavity) is absent in the RANS results but well predicted by DES. The 2nd mode is thought to arise from an interaction with vortical structures in the shear layer which are suppressed in the highly dissipative RANS method. The 4th mode, which is much weaker than the other three modes, is over-predicted by DES and under-predicted by a smaller amount in RANS.
Impact of privatisation on the financial and economic performance of European airports
Authors: Vogel H.-A. 
Published: February 2016

AbstractThis paper assesses the financial performance of 35 European airports for the decade 1990 to 2000, comparing those subject to partial or full privatisation with those still in public ownership. In contrast to earlier research, the outcomes of partial factor productivity (PFP), financial ratio (FRA) and data envelopment analysis (DEA) are evaluated, in order to investigate differences attributable to the degree of privatisation. Changes in performance after a change in ownership structure are reviewed. The analysis of sample data reveals economically meaningful and statistically significant differences between publicly owned and privatised airports. The major differences lie in operating efficiency, capital productivity and capital structure. Although partially and fully privatised airports operate more efficiently, this does not translate into significantly higher returns on shareholders’ funds. Due to their at least indirectly government-backed credit standing, publicly owned airport companies can assume more debt relative to their respective equity. This results in considerably higher gearing and financial leverage, which compensates for the comparatively low return rate on assets.
Aerofoil profile and sweep optimisation for a blended wing-body aircraft using a discrete adjoint method
Authors: Moigne A. Le , Qin N. 
Published: February 2016

AbstractAerodynamic optimisations of a blended wing-body (BWB) aircraft are presented. A discrete adjoint solver is used to calculate efficiently the gradients, which makes it possible to optimise for a large number of design variables. The optimisations employ either a variable-fidelity method that combines low- and high-fidelity models or a direct sequential quadratic programming (SQP) method. Four Euler optimisations of a BWB aircraft are then presented. The optimisation is allowed to change a series of master sections defining the aircraft geometry as well as the sweep angle on the outer wing for two of the optimisations. Substantial improvements are obtained, not only in the Euler mode but also when the optimised geometries are evaluated using Reynolds-averaged Navier-Stokes solutions. Some interesting features of the optimised wing profiles are discussed.
Numerical exploration of starting process in supersonic nozzle
Authors: Saha S. , Chakraborty D. 
Published: February 2016

AbstractThe starting process in a supersonic nozzle is numerically simulated. The Navier Stokes equations, in axisymmetric form, are solved using a higher order spatial and temporal accurate scheme. Good comparisons between experimental and numerical values of various flow parameters form the basis of further analysis. The insight of the starting process in the nozzle, namely, the movement of primary and secondary shocks and contact discontinuity, has been obtained through analysis of various flow parameters. It has been observed that the inviscid phenomenon is more predominant in the flow development process. Parametric studies have been carried out to determine the effect of nozzle divergence angle on the starting process.
Measuring the effect of helicopter rotors on GPS reception
Authors: Brodin G. J. , Cooper J. A. , Stevens J. R. A. 
Published: February 2016

AbstractThis paper describes an experiment which was performed using an offshore transport helicopter to investigate the impact of the rotor blades upon Global Positioning System (GPS) reception.The test aircraft was fitted with two separate GPS antennas which were positioned to isolate the effects caused by the main and tail rotors. Testing was undertaken with the aircraft on the ground and this allowed an assessment to be performed at different rotor speeds with accurate control over the relative geometry between the antenna, rotors and satellites.Recorded data from a measurement system incorporating three dissimilar GPS receivers (including a technical standard order (TSO)-C129() compliant aviation unit and a custom research receiver) was analysed to identify the effect of the rotors at the correlator level and to determine the impacts upon ranging accuracy, the availability of ranging measurements, and the receivers’ signal level estimates.Correlation data was used to demonstrate that the rotor blades were capable of generating both destructive and constructive interference effects, and the periodic nature of these oscillations was shown to correspond directly to the blade passing frequency. It was identified that signal degradation was not limited to satellite signal paths which intersected the rotor discs.No evidence was found for any increase in code measurement error due to the rotor interference, but it was demonstrated that there could be a significant impact upon a receiver’s ability to maintain continuous tracking of the satellite signals. The overall effect of this availability problem for a given installation and type of operation will be dependent upon satellite geometry and other factors which are beyond the scope of this study.The ability of a receiver to identify the presence of rotor interference was investigated by examining estimates of carrier-to-noise, and this revealed inconsistencies between the results from different receivers implying differences in the estimation algorithms employed. It was also identified that two alternative ‘textbook’ estimators do not give identical results in the presence of rotor interference and it is suggested that such data should therefore be interpreted with caution.
Three-dimensional tensile stress concentration in countersunk rivet holes
Authors: Bhargava A. , Shivakumar K. N. 
Published: February 2016

AbstractA detailed and accurate three-dimensional finite element stress analysis was conducted on countersunk rivet holes in a plate subjected to tension loading. The analysis included a wide range of countersunk depths, plate thicknesses, countersunk angles and plate widths. The study confirmed some of the previous results, addressed their differences, provided many new results, and investigated countersunk angle and width effects. Using the detailed FE results and the limiting conditions, a design equation for stress concentration was developed and verified.
Experimental and computational
investigation into the use of co-flow fluidic thrust
vectoring on a small gas turbine
Authors: Banazadeh A. , Saghafi F. , Ghoreyshi M. , Pilidis P. 
Published: February 2016

AbstractThis paper presents the application of a relatively new
technique of fluidic thrust-vectoring (FTV), named
Co-flow, for a small gas-turbines. The performance
is obtained via experiment and computational fluid
dynamics (CFD). The effects of a few selected
parameters including the engine throttle setting,
the secondary air mass-flow rate and the secondary
slot height upon thrust-vectoring performance are
provided. Thrust vectoring performance is
characterised by the ability of the system to
deflect the engine thrust with respect to the
delivered secondary air mass-flow rate. The
experimental study was conducted under static
conditions in an outdoor environment at Cranfield
University workshop that was especially designed for
this purpose. As part of this investigation, the
system was modelled by CFD techniques, using
Pointwise’s Gridgen software and the
three-dimensional flow solver, Fluent. Also,
Cranfield’s gas-turbine performance code
(TurboMatch) was utilised to estimate boundary
conditions for the CFD analysis with respect to the
integrated nozzle. The presented technique is
easy-to-use approach and offers better result for
thrust-vectoring problems than previously published
works. Experimental results do show the overall
viability of the blowing slot mechanism as a means
of vectoring the engine thrust, with the current
configuration. Computational predictions are shown
to be consistent with the experimental observations
and make the CFD model a reliable tool for
predicting Co-flow fluidic thrust-vectoring
performance of similar systems.