bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long time series (1984–2020) of albedo variations on the Greenland ice sheet from harmonized Landsat and Sentinel 2 imagery
Authors: Feng Shunan , Cook Joseph Mitchell , Anesio Alexandre Magno , Benning Liane G. , Tranter Martyn 
Published: March 2023

AbstractAlbedo is a key factor in modulating the absorption of solar radiation on ice surfaces. Satellite measurements have shown a general reduction in albedo across the Greenland ice sheet over the past few decades, particularly along the western margin of the ice sheet, a region known as the Dark Zone (albedo < 0.45). Here we chose a combination of Landsat 4–8 and Sentinel 2 imagery to enable us to derive the longest record of albedo variations in the Dark Zone, running from 1984 to 2020. We developed a simple, pragmatic and efficient sensor transformation to provide a long time series of consistent, harmonized satellite imagery. Narrow to broadband conversion algorithms were developed from regression models of harmonized satellite data and in situ albedo from the Program for Monitoring of the Greenland Ice Sheet (PROMICE) automatic weather stations. The albedo derived from the harmonized Landsat and Sentinel 2 data shows that the maximum extent of the Dark Zone expanded rapidly between 2005 and 2007, increasing to ~280% of the average annual maximum extent of 2900 km2 to ~8000 km2 since. The Dark Zone is continuing to darken slowly, with the average annual minimum albedo decreasing at a rate of $\sim \!-0.0006 \pm 0.0004 \, {\rm a}^{-1}$ (p = 0.16, 2001–2020).
Buckling of circular cylinders due to transverse shear, axial compression and normal pressure
Authors: Meyer R. R. 
Published: March 2023

SummaryBuckling equations for stiffened cylinders under the specified loading are formulated and solved by means of double Fourier series using the Galerkin process to reduce the solution to the standard algebraic eigen-value problem. Matrices of order 80 by 80 are required for convergence reflecting the complexity of the mode shape describing the buckling patterns.Simple design curves are developed for determining buckling loads of monocoque cantilever loaded cylinders.Excellent agreement with test values is demonstrated, indicating that the cylinders are not highly sensitive to imperfections, as is the case of the uniform, axially loaded cylinder. This also follows from the fact that considerable post buckling strength exists for the cantilever loading condition.
The prediction of separated flow using a viscous-inviscid interaction method
Authors: Williams B.R. 
Published: March 2023

SummaryThe separation of boundary-layer flow from a wing or in a diffuser usually defines the limit of efficient operation, so it is important that the onset and development of separated flow can be predicted. The calculation of the interaction of the shear layout close to an aerofoil with the external inviscid flow has offered an attractive alternative to solving the Reynoldsaveraged Navier Stokes equations for attached flow: the interaction method is much faster. In this paper it is shown how the interaction approach can be extended for use with separated flows and the development of a practical method is described. The calculation of the shear layer through the singularity at separation is accomplished by using an inverse mode. Beyond separation the empirical definition of a new family of velocity profiles allows an integral calculation of the shear layer to proceed up to the reattachment. The solutions for the shear layer close to the aerofoil are matched to the external inviscid flow by a ‘semi-inverse’ method. A careful examination of the stability of this method leads to rapid convergence for separated and attached flows. As an illustration the stall and post stall behaviour of a twodimensional aerofoil is predicted and compared with experimental results.
On the teaching of the principles of wing flexure-torsion flutter
Authors: Hancock G. J. , Wright J. R. , Simpson A. 
Published: March 2023

This note attempts to clarify some basic ideas, and correct some common misunderstandings, on wing flexure-torsion flutter. Topics include:(i) an understanding of the physics of wing flexure-torsion flutter through a number of specific examples,(ii) an examination of the energy interpretation of the physics of flutter, indicating its limited usefulness,(iii) a discussion of the significant differences between wing flexure-torsion flutter and the Duncan flutter engine,(iv) a graphical representation to assess the contribution of various parameter to flutter onset,(v) subcritical response below the critical flutter speed,(vi) some practical wing flutter considerations.
An exact integral (field panel) method for the calculation of two-dimensional transonic potential flow around complex configurations
Authors: Sinclair P. M. 
Published: March 2023

SummaryAn exact integral formulation of the two-dimensional full potential equation is presented. The well developed standard surface panel method based on the linear Prandtl-Glauert equation is extended by means of sources in the field surrounding the configuration, allowing the calculation of transonic flows.A major attraction of the Field Panel Method is that solutions can be obtained using standard surface panelling together with a field grid which has no special form. The surface panels are used to satisfy the boundary conditions so that the field grid does not have to be surface-fitted which is a requirement for existing field methods. Further, the grid need only be in a region close to the configuration where nonlinear compressibility effects are non-negligible and need not extend to the far field as generally required. Grid generation is therefore trivial allowing solutions for arbitrary configurations. Convergence, especially for flows with shock waves, is enhanced by use of a modified Approximate Factorisation scheme. Results for single aerofoils are compared with Garabedian-Korn solutions and show good agreement; and to demonstrate the ease of grid generation, results for multicomponent aerofoils are also presented. Finally, an outline is given of how the method can be extended to threedimensions.The work was carried out in conjunction with the Department of Applied Mathematics, University of Leeds together with Procurement Executive, Ministry of Defence.
The fundamentals of body-freedom flutter
Authors: Niblett LL. T 
Published: March 2023

SummaryThe object of this paper is to uncover the nature of the destabilising coupling that is the major cause of body-freedom flutter and to see whether a simple cure for the flutter can be found. To do this frequency-coalesence theory is applied to a simple aircraft. It is shown that the aircraft is liable to flutter if it has a sweptforward wing and a positive ‘tail-off’ cg margin or a sweptback wing and a negative cg margin but a simple cure for the flutter does not appear to exist.
Upstream influence on turbulent jet flows from cruciform nozzles
Authors: Quinn W. R , Marsters G. F 
Published: March 2023

The mixing of single or multiple jets is relevant in several engineering applications ranging from flame stabilisation in combustion to high lift devices for V/STOL aircraft. In some of these applications, expeditious manufacturing and ease of installation may dictate the use of sharp-edged slots in preference to nozzles with contoured upstream shaping.It has been suggested that cruciform nozzle exit shapes may be suitable for improving mixing and thus thrust augmentation in STOL aircraft. The effects of nozzle geometry on the performance of an axisymmetric thrust augmentor have been investigated experimentally and a very slight improvement in the performance of the axisymmetric thrust augmentor was observed when cruciform nozzles were used after the tests had been performed with circular nozzles.
Spurious entropy production and very accurate solutions to the Euler equations
Authors: Rizzi Arthur 
Published: March 2023

AbstractSince it is not assumed a priorito be constant, entropy can vary along streamlines in the numerical solution of the Euler equations, depending upon its accuracy, even if the flow is isentropic. The level of this spurious entropy (or equivalently loss in total pressure) produced in the solution has become a common measure for the accuracy of the solution. It was used in a recent exercise by the AGARD Working Group 07 as one of the primary criteria to judge the most accurate solutions of the Euler equations for a variety of different test problems. Of the four possible sources of this error: mesh spacing, convective difference scheme, artificial viscosity model, and boundary conditions, the latter two are found to contribute the most. The steps taken to limit the errors coming from each of these four areas are described in detail in the context of two AGARD test cases: NACA 0012 M∞, = 0·85 α= 1 deg, and NLR 7301 M∞ = 0·721 α=-0·194 deg. An accurate shock-free supercritical solution is presented for the latter case.
The interaction of a wake with a turbulent boundary layer
Authors: Zhou Ming De , Squire L.C. 
Published: March 2023

SummaryIn the flow over high-lift aerofoils there is a strong interaction between the wake from one element and the boundary layer on another element immediately downstream. A number of experimental investigation of these types of flow have been made but these studies do not allow the effects associated with the various parameters of the aerofoil to be seen easily. This paper presents the results of extensive measurements of mean and fluctuating quantities made in merging layers in zero and adverse pressure gradients downstream of aerofoils of various shapes. A general description of the emerging process is given and the effects of wake characteristics and pressure gradient are considered. The paper also contains a discussion of the modelling of the Reynolds shear stress in the merging layer.
On aircraft flight performance in a perturbed atmosphere
Authors: Campos L. M. B. C. 
Published: March 2023

SummaryWe consider the effect of atmospheric disturbances, such as wind, shears, turbulence, wakes and downflows, on aircraft performance (section 1), recalling the minimum of aerodynamics (section 2) necessary for the calculation of the effects on flight mechanics. For example, it is shown (section 3) that the relative lift change, due to wind, shear or both, coincides with the disturbance intensity G, defined as the instantaneous vertical acceleration, measured in g's, that an aircraft will experience as a consequence of atmospheric disturbances, assuming constant velocity and attitude. The disturbance intensity is a measure of the total force that the atmospheric disturbance can exert on the aircraft; this force may cause changes in normal acceleration, flight velocity and angle-of-attack, either isolated (section 5) or combined (section 6), in straight and level flight; in the case of a horizontal turn (section 7), the disturbance intensity specifies the changes in instantaneous turn rate, velocity, radius (section 8), acceleration and bank angle (section 9) due to atmospheric perturbations, and their cumulative effect over time in (section 10) deforming and displacing trajectories. These effects (section 11) are quantified by formulas and illustrated in graphics, and we indicate throughout the flight mechanical consequences of disturbances with the critical intensities G1 = — 0·17 and G2 = — 0·42; these are the disturbance intensities which, if uncompensated, would be just enough to cause an aircraft to stall (section 4) respectively at unstick on take-off and on approach to land. We conclude (section 12) with a discussion of the use of the disturbance intensity as a parameter in the reduction and analysis of flight data.
New rotary rig at RAE and experiments on HIRM
Authors: O’Leary C. O. , Rowthorn E. N. 
Published: March 2023

SummaryA rig for measurement of forces and moments due to continuous rate of roll has been commissioned at RAE Bedford. Tests have been made on a High Incidence Research Model (HIRM) in two wind tunnels at M = 0·2, 0·4 and 0·7. At present models can be tested up to 40° angle of attack at rotational speeds up to 350 rpm.Tests on HIRM included an investigation of configuration and Reynolds number effects. Results are compared with similar data from tests with another rolling rig and from small amplitude oscillatory tests.
Performance of the Wells self-rectifying air turbine
Authors: Raghunathan S. , Tan C. P. , Ombaka O. O. 
Published: March 2023

SummaryAnalytical and experimental studies of the effect of geometric and aerodynamic variables on the performance of the Wells self-rectifying air turbine are presented in this paper. Two approaches to the prediction of the Wells turbine performance are described, both of which are based on the two dimensional cascade theory and isolated aerofoil data. Experimental results are based on the investigations in Unidirectional and oscillating airflow rigs.Comparisons are made on the analytical and experimental results.
Test cases for the plane potential flow past multi-element aerofoils
Authors: Suddhoo A. , Hall I. M. 
Published: March 2023

SummaryThe method of images is used to calculate the analytical solution for an inviscid incompressible flow past four arbitrary circles which are then conformally mapped onto aerofoil sections. The analytical solution of the corresponding flow past the system of aerofoils is obtained and the pressure distributions about a particular three-element and a particular fourelement aerofoil are presented. These results are intended to be used to assess the accuracy of numerical methods.
Impact of salinity on yield-related parameters in two contrasting cultivars ofOryza glaberrimaSteud. in Benin
Authors: Prodjinoto Hermann , Gandonou Christophe , Irakoze Willy , Lutts Stanley 
Published: March 2023

SummarySalinity is one of the major environmental stresses limiting growth and yield of rice. The objective of the present study was to analyze the impact of NaCl on yield-related parameters ofOryza glaberrima. Two contrasted cultivars ofOryza glaberrimapreviously tested for salt resistance at the vegetative stage [salt-resistant (TOG5307) and salt-sensitive (TOG5949)] were irrigated with a saline solution containing 30 mM NaCl (EC: 3 dS.m−1NaCl). After 6 months of treatments, mineral nutrient and yield-related parameters were assessed. Proline was quantified in the panicle leaf at the start of the grain filling stage. NaCl treatment affected most yield-related parameters: panicle length, panicle leaf dry weight, number of branches per panicle, panicle leaf length, days to 50% heading, straw fresh weight per plant, grain yield per plant, number of spikelets per panicle, and number of filled grains per panicle. The weight of 1,000 grains decreased in the salt-sensitive cultivar only, suggesting that grain filling processes were compromised. The salt-resistant cultivar TOG5307 was less affected than the salt-sensitive TOG5949 and accumulated lower amounts of Na+in the grains. For both cultivars, hulls contained higher concentration of Na+and K+than grains. TOG5307 also contained more proline in the panicle leaf than TOG5949, suggesting that TOG5307 can cope with the osmotic component of salt stress. The cultivar exhibiting the highest salt resistance at the vegetative stage also exhibited the highest resistance at the reproductive one.
Reimagining conservation practice: Indigenous self-determination and collaboration in Papua New Guinea
Authors: Aini John , West Paige , Amepou Yolarnie , Piskaut Michael Ladi , Gasot Cornelius , James Rachel S. , Roberts Jason Steadman , Nason Patrick , Brachey Anna Elyse 
Published: March 2023

AbstractHere we describe a 14-year collaboration in New Ireland, Papua New Guinea, between an Indigenous NGO, Indigenous scientists and international researchers. New Ireland is a marine province in the Western Pacific region where most residents depend on fishing, marine gleaning and small-scale gardening for their livelihoods. Ailan Awareness is a locally founded and managed NGO that focuses on the strengthening of Indigenous sovereignty regarding biological, cultural and spiritual diversity as well as fostering Indigenous epistemology practices and strengthening biocultural diversity. In partnership with anthropological researchers, Ailan Awareness has designed an approach to marine conservation informed by the growing field of decolonial research practices. By working to empower coastal communities to make decisions about their marine and cultural resources using a mix of Indigenous, anthropological and scientific methods and giving primacy to strengthening Indigenous modes of knowledge production and the role of community Elders, Ailan Awareness addresses a major gap in the efforts of the national government and international NGOs: giving the people most directly affected by declining biodiversity and loss of tradition the support and tools required to design and carry out the strengthening of both biological diversity and traditional social practices. In this paper we describe the methodology used by Ailan Awareness and the history of collaboration that resulted in these methods.
Geographical variation in hepatitis C-related severe liver disease and patient risk factors: a multicentre cross-sectional study
Authors: Nickbakhsh Sema , McWilliam Leitch E. Carol , Smith Shanley , Davis Chris , Hutchinson Sharon , Irving William L. , McLauchlan John , Thomson Emma C. 
Published: March 2023

Abstract
Despite promising steps towards the elimination of hepatitis C virus (HCV) in the UK, several indicators provide a cause for concern for future disease burden. We aimed to improve understanding of geographical variation in HCV-related severe liver disease and historic risk factor prevalence among clinic attendees in England and Scotland. We used metadata from 3829 HCV-positive patients consecutively enrolled into HCV Research UK from 48 hospital centres in England and Scotland during 2012–2014. Employing mixed-effects statistical modelling, several independent risk factors were identified: age 46–59 y (ORadj 3.06) and ≥60 y (ORadj 5.64) relative to <46 y, male relative to female sex (ORadj 1.58), high BMI (ORadj 1.73) and obesity (ORadj 2.81) relative to normal BMI, diabetes relative to no diabetes (ORadj 2.75), infection with HCV genotype (GT)-3 relative to GT-1 (ORadj 1.75), route of infection through blood products relative to injecting drug use (ORadj 1.40), and lower odds were associated with black ethnicity (ORadj 0.31) relative to white ethnicity. A small proportion of unexplained variation was attributed to differences between hospital centres and local health authorities. Our study provides a baseline measure of historic risk factor prevalence and potential geographical variation in healthcare provision, to support ongoing monitoring of HCV-related disease burden and the design of risk prevention measures.
“An Isolating Experience Aggravated by COVID”: Exploring Disconnections Between Political Science PhD Candidates and Supervisors
Authors: Rutledge-Prior Serrin , Casey Daniel 
Published: March 2023

ABSTRACTTo what extent did the COVID-19 pandemic impact PhD candidates in political science? To what extent were their supervisors aware of this impact? PhD candidates in political science are not strangers to the lack of available and stable academic employment and the potentially isolating experience of research. Our survey of Australian PhD candidates in political science and international relations (N = 109) confirms that the COVID-19 pandemic exacerbated these preexisting challenges. By comparing political science PhD candidates and their supervisors in relation to their experiences during the pandemic, our survey also reveals that there has been a disconnect between the two groups relative to the former’s experience of COVID-19. Although supervisors recognize the stressors that candidates have faced, they are more likely than candidates to report that department support relative to pandemic-related challenges was available, and they appear to be somewhat unaware of the impact that COVID-19 has had on candidates’ career plans. The survey also reveals substantial disagreement between candidates and supervisors about perceived career-mentoring styles. These points of disconnect must be addressed to ensure the success and well-being of current and future PhD candidates.
To protest or not to protest? Migrant workers’ participation in protests in China
Authors: Chen Yen-Hsin , Mason T. David 
Published: March 2023

AbstractWe present a theoretical explanation for why migrant workers in China should be less likely to participate in protests than other categories of workers. While grievance-based theories of protest would suggest that migrant workers have more incentive to protest than other categories of workers, resource mobilization theory suggests that their capacity to mobilize for collective action is impeded by the conditions of their work situation and their residence. Using survey data from CGSS 2010, we test propositions derived from this framework. We find that a greater sense of relative deprivation is associated with a greater likelihood of participating in protest across all categories of workers. However, we also find that migrant worker status functions as a moderator between grievances and protest participation: compared to urban registered workers, migrant workers are significantly less likely to take part in protest activities when both of them have high levels of perceived unfairness. These findings are robust across all models.
Planetary geodynamics and age constraints on circumstellar habitable zones around main sequence stars
Authors: Mello Fernando de Sousa , Friaça Amâncio César Santos 
Published: March 2023

AbstractPlanetary geodynamics may have an important influence over planetary habitability and the boundaries of the circumstellar habitable zone (CHZ) in space and time. To investigate this we use a minimal parameterized model of the co-evolution of the geosphere and atmosphere of Earth-like planets around F, G, K and M main sequence stars. We found the CHZ for the present Solar System located between 0.92 and 1.09 au for a 1.0 M$_{\oplus }$Earth-like planet, extendible to 1.36 au for a 4.0 M$_{\oplus }$planet. In the literature, the CHZ varies considerably in width and border location, but the outer edges tend to be more spread out than the inner edges, showing a higher difficulty in determining the outer edge. Planetary mass has a considerable effect on planetary geodynamics, with low-mass planets cooling down faster and being less capable of maintaining a rich carbon dioxide atmosphere for several billions of years. Age plays a particularly important role in the width of the CHZ as the CHZ contracts in both directions: from the inner edge (as stellar luminosity increases with time), and from the outer edge (as planetary heat flux and seafloor spreading rate decrease with time). This strongly affects long-lived habitability as the 5 Gyr continuous CHZ may be very narrow or even non-existent for low-mass planets (<0.5 M$_{\oplus }$) and fast-evolving high-mass stars (>1.1 M$_{\odot }$). Because of this, the mean age of habitable terrestrial planets in our Galaxy today may be younger than Earth's age. Our results suggest that the best targets for future surveys of biosphere signatures may be planets between 0.5 and 4.0 M$_{\oplus }$, in systems younger than the Solar System. These planets may present the widest and long-lived CHZ.