David C. Stapleton
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Complexes of stable birational invariants Open
We introduce a new stable birational invariant, which takes the form of a functor sending a degenerating variety to the homotopy type of a chain complex. Our invariant is a categorification of the motivic volume of Nicaise and Shinder. Fro…
Influence of melt parameters on the microstructure of electron beam melted Ti–6Al–4V Open
Additively manufactured, Electron Beam Melted (EBM) specimens of the titanium alloy, Ti–6Al–4V, have been produced using a process window determined through a normalised energy density method. Two batches were manufactured and compared usi…
View article: Smooth limits of plane curves of prime degree and Markov numbers
Smooth limits of plane curves of prime degree and Markov numbers Open
In dimension at least 3, Mori asked if every smooth proper limit of a family of prime degree hypersurfaces is still a hypersurface. In dimensions 1 and 2, this is not the case. For example, it is well known that quintic plane curves can de…
View article: Gamma prime precipitation in as-deposited Ni-based superalloy IN713LC
Gamma prime precipitation in as-deposited Ni-based superalloy IN713LC Open
The as-deposited microstructure of an additively manufactured Ni-based superalloy fabricated using laser powder-bed-fusion has been investigated using atomic resolution transmission electron microscopy. It is shown that γ′ precipitates exi…
The fibering genus of Fano hypersurfaces Open
Kollár proved that a very general $n$-dimensional complex hypersurface of degree at least $3\lceil (n+3)/4\rceil$ is not birational to a fibration in rational curves. This is most interesting when the hypersurface is Fano, in which case it…
Minimal degree fibrations in curves and the asymptotic degree of irrationality of divisors Open
In this paper we study the degrees of irrationality of hypersurfaces of large degree in a complex projective variety. We show that the maps computing the degrees of irrationality of these hypersurfaces factor through rational fibrations of…
View article: Smooth limits of plane curves of prime degree and Markov numbers
Smooth limits of plane curves of prime degree and Markov numbers Open
For prime degree hypersurfaces of dimension at least 3, Mori asked if every smooth proper limit is still a hypersurface. Interestingly in dimensions 1 and 2, this is not the case. For example, Griffin constructed explicit families of quint…
Fano hypersurfaces with no finite order birational automorphisms Open
We use the specialization homomorphism for the birational automorphism group to study finite order birational automorphisms. For a family of varieties over a DVR, we prove that a birational automorphism of order coprime to the residue char…
Hyperkähler manifolds Open
We give an elementary introduction to hyperkähler manifolds, survey some of their interesting properties and some open problems.
Effect of Process Parameters and Build Orientation on Microstructure and Impact Energy of Electron Beam Powder Bed Fused Ti-6Al-4V Open
To fully exploit the benefits of additive manufacturing (AM), an understanding of its processing, microstructural, and mechanical aspects, and their interdependent characteristics, is necessary. In certain instances, AM materials may be de…
Research to Inform Policy: Contributions of the Mathematica Center for Studying Disability Policy Open
This article summarizes selected findings from work conducted under the Social Security Administration’s Disability Research Consortium by researchers at the Mathematica Center for Studying Disability Policy (CSDP).
The Influence of Process Parameters and Build Orientation on the Creep Behaviour of a Laser Powder Bed Fused Ni-based Superalloy for Aerospace Applications Open
Additive Layer Manufacturing (ALM) is an innovative net shape manufacturing technology that offers the ability to produce highly intricate components not possible through traditional wrought and cast procedures. Consequently, the aerospace…
High temperature mechanical deformation of an additive manufactured nickel based superalloy using small scale test methods Open
Nickel based superalloys have been utilised within numerous industrial sectors from power generation to chemical processing plants for over four decades as a result of their ability to retain mechanical properties at arduous temperatures a…
Employing Those Not Expected to Work: The Stunning Changes in the Employment of Single Mothers and People with Disabilities in the United States in the 1990s* Open
In sharp contrast to single women with children, the employment rates of men and women stunningly declined over the 1990s business cycle after rising over the 1980s business cycle. United States policy-makers were successful in increasing …
Predicting Receipt of Social Security Administration Disability Benefits Using Biomarkers and Other Physiological Measures: Evidence From the Health and Retirement Study Open
Objectives: The objective of this study was to assess how well physiological measures, including biomarkers and genetic indicators, predict receipt of Social Security Administration (SSA) disability benefits among U.S. adults aged 51 to 65…
Using the Health and Retirement Study for Disability Policy Research: A Review Open
http://deepblue.lib.umich.edu/bitstream/2027.42/196296/1/Stapleton Schimmel Using the Health and Retirement Study for Disability Policy Research.pdf