Smooth solutions for the dyadic model

We consider the dyadic model, which is a toy model to test issues of well-posedness and blow-up for the Navier-Stokes and Euler equations. We prove well-posedness of positive solutions of the viscous problem in the relevant scaling range which corresponds to Navier-Stokes. Likewise we prove well-posedness for the inviscid problem (in a suitable regularity class) when the parameter corresponds to the strongest transport effect of the non-linearity

Two-Photon Spiral Imaging with Correlated Orbital Angular Momentum States

The concept of correlated two-photon spiral imaging is introduced. We begin by analyzing the joint orbital angular momentum (OAM) spectrum of correlated photon pairs. The mutual information carried by the photon pairs is evaluated, and it is shown that when an object is placed in one of the beam paths the value of the mutual information is strongly dependent on object shape and is closely related to the degree of rotational symmetry present. After analyzing the effect of the object on the OAM correlations, the method of correlated spiral imaging is described. We first present a version using parametric downconversion, in which entangled pairs of photons with opposite OAM values are produced, placing an object in the path of one beam. We then present a classical (correlated, but non-entangled) version. The relative problems and benefits of the classical versus entangled configurations are discussed. The prospect is raised of carrying out compressive imaging via twophoton OAM detection to reconstruct sparse objects with few measurements

Thermomechanical deformation behavior of a dynamic strain aging alloy, Hastelloy X

An experimental study was performed to identify the effects of dynamic strain aging (solute drag) and metallurgical instabilities under thermomechanical loading conditions. The study involved a series of closely controlled thermomechanical deformation tests on the solid-solution-strenghened nickel-base superalloy, Hastelloy X. This alloy exhibits a strong isothermal strain aging peak at approximately 600 C, promoted by the effects of solute drag and precipitation hardening. Macroscopic thermomechanical hardening trends are correlated with microstructural characteristics through the use of transmission electron microscopy. These observations are compared and contrasted with isothermal conditions. Thermomechanical behavior unique to the isothermal database is identified and discussed. The microstructural characteristics were shown to be dominated by effects associated with the highest temperature of the thermomechanical cycle. Results indicate that the deformation behavior of Hastelloy X is thermomechanically path dependent. In addition, guidance is given pertaining to deformation modeling in the context of macroscopic unified theory. An internal state variable is formulated to qualitatively reflect the isotropic hardening trends identified in the TMD experiments

Livelihood Disruption and Venture Creation: Entrepreneurship as Technology Adoption, A Case of Tobacco Farmer in Kentucky

Entrepreneurship means making discrete changes in livelihood activities that involve substantial risks to income. While the rewards may be substantial, transactions costs may make decisions irreversible. This paper draws a comparison between entrepreneurship and technology adoption. Adopting a new production technology also involves substantial risks. The economics of technology adoption is a well developed literature with many accepted and testable models. Most prominent are the theories of learning by using and learning by doing. We review the technology adoption literature, drawing out lessons for entrepreneurship research. We then apply an entrepreneurship as technology adoption model to a unique dataset collected during the tobacco buyout. The uncertainty in household income and changes in economic environment during the tobacco transition payment program lead many individuals into entrepreneurial activities.entrepreneurship, technology adoption, tobacco buyout, Agribusiness, Risk and Uncertainty,

Livelihood Disruption and Venture Creation: Entrepreneurship as Technology Adoption A Comparison between Kentucky and Shaanxi Farmers

In the US, The Tobacco Transition Payment Program, also called the "tobacco buy-out," helps tobacco quota holders and producers transition to the free market. In China, the transaction of Land Use Rights providing farmers’ ability to buy or sell Land Use Rights has been seriously considered by the Chinese government. The uncertainty in household income and changes in economic environment during the US Tobacco Transition Payment Program and the Chinese Land Use Rights Regime lead many individuals into entrepreneurial activities. Entrepreneurship often means making changes in livelihood activities that involve substantial risks to income. While the rewards may be substantial, transactions costs may make decisions irreversible. This paper draws a comparison between entrepreneurship and technology adoption. Adopting a new production technology also involves substantial risks. The economics of technology adoption is a well developed literature with many accepted and testable models. Most prominent are the theories of learning by using and learning by doing. We review the technology adoption literature, drawing out lessons for entrepreneurship research. We then apply an ‘entrepreneurship as technology adoption’ model to a unique dataset collected in Kentucky, US and in Shaanxi province, China. Using a sample of 702 Kentucky farmers at the time of the buyout and 730 Chinese farmers, we test several of the implications of this model and compare significant results between Kentucky and Shaanxi farmers. This study finds that both farmers in Kentucky and Shaanxi with a strong social network are more likely to become entrepreneurs. Kentucky farmers with low income are more likely to start new businesses. The finding supports the “push” hypothesis as farmers with low income are pushed into starting a new business. The human capital factor is strongly associated with Shaanxi farmer’s entrepreneurial decision.Farm Management, Research and Development/Tech Change/Emerging Technologies,

Complete Integrability of Geodesic Motion in General Kerr-NUT-AdS Spacetimes

We explicitly exhibit n-1 constants of motion for geodesics in the general D-dimensional Kerr-NUT-AdS rotating black hole spacetime, arising from contractions of even powers of the 2-form obtained by contracting the geodesic velocity with the dual of the contraction of the velocity with the (D-2)-dimensional Killing-Yano tensor. These constants of motion are functionally independent of each other and of the D-n+1 constants of motion that arise from the metric and the D-n = [(D+1)/2] Killing vectors, making a total of D independent constants of motion in all dimensions D. The Poisson brackets of all pairs of these D constants are zero, so geodesic motion in these spacetimes is completely integrable.Comment: 4 pages. We have now found that the geodesic motion is not just integrable, but completely integrabl