234 research outputs found
Convective and radiative heat transfer to an ablating body, part I Final report
Convective and radiative heat transfer to entry vehicles with ablative heat shiel
Effect of shock precursor heating on radiative flux to blunt bodies
Effect of shock precursor heating on radiative flux to blunt bodie
Stagnation point flow with radiation
Coupling between inviscid and viscid flows in hypersonic stagnation region investigated at high flight velocities with significant radiative heat transfe
Innovative Delivery Of MBA Business Foundation Coursework: Does Integrated, Team Teaching Make A Difference?
Team-teaching is often viewed as a viable alternative to traditional delivery approaches in graduate business programs. However there is little research to support the benefits of team-teaching from a student learning perspective. This paper demonstrates that student achievement in “downstream” MBA courses is significantly improved when they complete integrated, team-taught business foundation courses
Density Functional for Anisotropic Fluids
We propose a density functional for anisotropic fluids of hard body
particles. It interpolates between the well-established geometrically based
Rosenfeld functional for hard spheres and the Onsager functional for elongated
rods. We test the new approach by calculating the location of the the
nematic-isotropic transition in systems of hard spherocylinders and hard
ellipsoids. The results are compared with existing simulation data. Our
functional predicts the location of the transition much more accurately than
the Onsager functional, and almost as good as the theory by Parsons and Lee. We
argue that it might be suited to study inhomogeneous systems.Comment: To appear in J. Physics: Condensed Matte
Global Investments in Pandemic Preparedness and COVID-19: Development Assistance and Domestic Spending on Health Between 1990 and 2026
Background The COVID-19 pandemic highlighted gaps in health surveillance systems, disease prevention, and treatment globally. Among the many factors that might have led to these gaps is the issue of the financing of national health systems, especially in low-income and middle-income countries (LMICs), as well as a robust global system for pandemic preparedness. We aimed to provide a comparative assessment of global health spending at the onset of the pandemic; characterise the amount of development assistance for pandemic preparedness and response disbursed in the first 2 years of the COVID-19 pandemic; and examine expectations for future health spending and put into context the expected need for investment in pandemic preparedness. Methods In this analysis of global health spending between 1990 and 2021, and prediction from 2021 to 2026, we estimated four sources of health spending: development assistance for health (DAH), government spending, out-ofpocket spending, and prepaid private spending across 204 countries and territories. We used the Organisation for Economic Co-operation and Development (OECD)’s Creditor Reporting System (CRS) and the WHO Global Health Expenditure Database (GHED) to estimate spending. We estimated development assistance for general health, COVID-19 response, and pandemic preparedness and response using a keyword search. Health spending estimates were combined with estimates of resources needed for pandemic prevention and preparedness to analyse future health spending patterns, relative to need. Findings In 2019, at the onset of the COVID-19 pandemic, US7·3 trillion (95% UI 7·2–7·4) in 2019; 293·7 times the 43·1 billion in development assistance was provided to maintain or improve health. The pandemic led to an unprecedented increase in development assistance targeted towards health; in 2020 and 2021, 37·8 billion was provided for the health-related COVID-19 response. Although the support for pandemic preparedness is 12·2% of the recommended target by the High-Level Independent Panel (HLIP), the support provided for the healthrelated COVID-19 response is 252·2% of the recommended target. Additionally, projected spending estimates suggest that between 2022 and 2026, governments in 17 (95% UI 11–21) of the 137 LMICs will observe an increase in national government health spending equivalent to an addition of 1% of GDP, as recommended by the HLIP. Interpretation There was an unprecedented scale-up in DAH in 2020 and 2021. We have a unique opportunity at this time to sustain funding for crucial global health functions, including pandemic preparedness. However, historical patterns of underfunding of pandemic preparedness suggest that deliberate effort must be made to ensure funding is maintained
The Shapes of Flux Domains in the Intermediate State of Type-I Superconductors
In the intermediate state of a thin type-I superconductor magnetic flux
penetrates in a disordered set of highly branched and fingered macroscopic
domains. To understand these shapes, we study in detail a recently proposed
"current-loop" (CL) model that models the intermediate state as a collection of
tense current ribbons flowing along the superconducting-normal interfaces and
subject to the constraint of global flux conservation. The validity of this
model is tested through a detailed reanalysis of Landau's original conformal
mapping treatment of the laminar state, in which the superconductor-normal
interfaces are flared within the slab, and of a closely-related straight-lamina
model. A simplified dynamical model is described that elucidates the nature of
possible shape instabilities of flux stripes and stripe arrays, and numerical
studies of the highly nonlinear regime of those instabilities demonstrate
patterns like those seen experimentally. Of particular interest is the buckling
instability commonly seen in the intermediate state. The free-boundary approach
further allows for a calculation of the elastic properties of the laminar
state, which closely resembles that of smectic liquid crystals. We suggest
several new experiments to explore of flux domain shape instabilities,
including an Eckhaus instability induced by changing the out-of-plane magnetic
field, and an analog of the Helfrich-Hurault instability of smectics induced by
an in-plane field.Comment: 23 pages, 22 bitmapped postscript figures, RevTex 3.0, submitted to
Phys. Rev. B. Higher resolution figures may be obtained by contacting the
author
Possible first order transition in the two-dimensional Ginzburg-Landau model induced by thermally fluctuating vortex cores
We study the two-dimensional Ginzburg-Landau model of a neutral superfluid in
the vicinity of the vortex unbinding transition. The model is mapped onto an
effective interacting vortex gas by a systematic perturbative elimination of
all fluctuating degrees of freedom (amplitude {\em and} phase of the order
parameter field) except the vortex positions. In the Coulomb gas descriptions
derived previously in the literature, thermal amplitude fluctuations were
neglected altogether. We argue that, if one includes the latter, the vortices
still form a two- dimensional Coulomb gas, but the vortex fugacity can be
substantially raised. Under the assumption that Minnhagen's generic phase
diagram of the two- dimensional Coulomb gas is correct, our results then point
to a first order transition rather than a Kosterlitz-Thouless transition,
provided the Ginzburg-Landau correlation length is large enough in units of a
microscopic cutoff length for fluctuations. The experimental relevance of these
results is briefly discussed. [Submitted to J. Stat. Phys.]Comment: 36 pages, LaTeX, 6 figures upon request, UATP2-DB1-9
Global investments in pandemic preparedness and COVID-19
Background The COVID-19 pandemic highlighted gaps in health surveillance systems, disease prevention, and
treatment globally. Among the many factors that might have led to these gaps is the issue of the financing of national
health systems, especially in low-income and middle-income countries (LMICs), as well as a robust global system for
pandemic preparedness. We aimed to provide a comparative assessment of global health spending at the onset of the
pandemic; characterise the amount of development assistance for pandemic preparedness and response disbursed in
the first 2 years of the COVID-19 pandemic; and examine expectations for future health spending and put into context
the expected need for investment in pandemic preparedness.
Methods In this analysis of global health spending between 1990 and 2021, and prediction from 2021 to 2026, we
estimated four sources of health spending: development assistance for health (DAH), government spending, out-ofpocket spending, and prepaid private spending across 204 countries and territories. We used the Organisation for
Economic Co-operation and Development (OECD)’s Creditor Reporting System (CRS) and the WHO Global Health
Expenditure Database (GHED) to estimate spending. We estimated development assistance for general health,
COVID-19 response, and pandemic preparedness and response using a keyword search. Health spending estimates
were combined with estimates of resources needed for pandemic prevention and preparedness to analyse future
health spending patterns, relative to need.
Findings In 2019, at the onset of the COVID-19 pandemic, US7·3 trillion (95% UI 7·2–7·4) in 2019; 293·7 times the 43·1 billion in development assistance was provided to maintain or
improve health. The pandemic led to an unprecedented increase in development assistance targeted towards health; in
2020 and 2021, 37·8 billion was provided for the health-related COVID-19 response. Although the support for pandemic preparedness
is 12·2% of the recommended target by the High-Level Independent Panel (HLIP), the support provided for the healthrelated COVID-19 response is 252·2% of the recommended target. Additionally, projected spending estimates suggest
that between 2022 and 2026, governments in 17 (95% UI 11–21) of the 137 LMICs will observe an increase in national
government health spending equivalent to an addition of 1% of GDP, as recommended by the HLIP.
Interpretation There was an unprecedented scale-up in DAH in 2020 and 2021. We have a unique opportunity at this
time to sustain funding for crucial global health functions, including pandemic preparedness. However, historical
patterns of underfunding of pandemic preparedness suggest that deliberate effort must be made to ensure funding is
maintained
Ginzburg-Landau theory of vortices in a multi-gap superconductor
The Ginzburg-Landau functional for a two-gap superconductor is derived within
the weak-coupling BCS model. The two-gap Ginzburg-Landau theory is, then,
applied to investigate various magnetic properties of MgB2 including an upturn
temperature dependence of the transverse upper critical field and a core
structure of an isolated vortex. Orientation of vortex lattice relative to
crystallographic axes is studied for magnetic fields parallel to the c-axis. A
peculiar 30-degree rotation of the vortex lattice with increasing strength of
an applied field observed by neutron scattering is attributed to the multi-gap
nature of superconductivity in MgB2.Comment: 11 page
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