Foundations of aeroelastic optimization and some applications to continuous systems

Static and dynamic aeroelastic problems in optimization of continuous system

Alien Registration- Morin, Armand L. (Biddeford, York County)

https://digitalmaine.com/alien_docs/4401/thumbnail.jp

First experimental demonstration of temporal hypertelescope operation with a laboratory prototype

In this paper, we report the first experimental demonstration of a Temporal HyperTelescope (THT). Our breadboard including 8 telescopes is firstly tested in a manual cophasing configuration on a 1D object. The Point Spread Function (PSF) is measured and exhibits a dynamics in the range of 300. A quantitative analysis of the potential biases demonstrates that this limitation is related to the residual phase fluctuation on each interferometric arm. Secondly, an unbalanced binary star is imaged demonstrating the imaging capability of THT. In addition, 2D PSF is recorded even if the telescope array is not optimized for this purpose.Comment: Accepted for publication in MNRAS. 11 pages, 25 figure

Slow flows of yield stress fluids: complex spatio-temporal behaviour within a simple elasto-plastic model

A minimal athermal model for the flow of dense disordered materials is proposed, based on two generic ingredients: local plastic events occuring above a microscopic yield stress, and the non-local elastic release of the stress these events induce in the material. A complex spatio-temporal rheological behaviour results, with features in line with recent experimental observations. At low shear rates, macroscopic flow actually originates from collective correlated bursts of plastic events, taking place in dynamically generated fragile zones. The related correlation length diverges algebraically at small shear rates. In confined geometries bursts occur preferentially close to the walls yielding an intermittent form of flow localization.Comment: 4 pages, 4 figure

Local yield stress statistics in model amorphous solids

We develop and extend a method presented in [S. Patinet, D. Vandembroucq, and M. L. Falk, Phys. Rev. Lett., 117, 045501 (2016)] to compute the local yield stresses at the atomic scale in model two-dimensional Lennard-Jones glasses produced via differing quench protocols. This technique allows us to sample the plastic rearrangements in a non-perturbative manner for different loading directions on a well-controlled length scale. Plastic activity upon shearing correlates strongly with the locations of low yield stresses in the quenched states. This correlation is higher in more structurally relaxed systems. The distribution of local yield stresses is also shown to strongly depend on the quench protocol: the more relaxed the glass, the higher the local plastic thresholds. Analysis of the magnitude of local plastic relaxations reveals that stress drops follow exponential distributions, justifying the hypothesis of an average characteristic amplitude often conjectured in mesoscopic or continuum models. The amplitude of the local plastic rearrangements increases on average with the yield stress, regardless of the system preparation. The local yield stress varies with the shear orientation tested and strongly correlates with the plastic rearrangement locations when the system is sheared correspondingly. It is thus argued that plastic rearrangements are the consequence of shear transformation zones encoded in the glass structure that possess weak slip planes along different orientations. Finally, we justify the length scale employed in this work and extract the yield threshold statistics as a function of the size of the probing zones. This method makes it possible to derive physically grounded models of plasticity for amorphous materials by directly revealing the relevant details of the shear transformation zones that mediate this process

Malaria’s Missing Number: Calculating the Human Component of R0 by a Within-Host Mechanistic Model of Plasmodium falciparum Infection and Transmission

Human infection by malarial parasites of the genus Plasmodium begins with the bite of an infected Anopheles mosquito. Current estimates place malaria mortality at over 650,000 individuals each year, mostly in African children. Efforts to reduce disease burden can benefit from the development of mathematical models of disease transmission. To date, however, comprehensive modeling of the parameters defining human infectivity to mosquitoes has remained elusive. Here, we describe a mechanistic within-host model of Plasmodium falciparum infection in humans and pathogen transmission to the mosquito vector. Our model incorporates the entire parasite lifecycle, including the intra-erythrocytic asexual forms responsible for disease, the onset of symptoms, the development and maturation of intra-erythrocytic gametocytes that are transmissible to Anopheles mosquitoes, and human-to-mosquito infectivity. These model components were parameterized from malaria therapy data and other studies to simulate individual infections, and the ensemble of outputs was found to reproduce the full range of patient responses to infection. Using this model, we assessed human infectivity over the course of untreated infections and examined the effects in relation to transmission intensity, expressed by the basic reproduction number R0 (defined as the number of secondary cases produced by a single typical infection in a completely susceptible population). Our studies predict that net human-to-mosquito infectivity from a single non-immune individual is on average equal to 32 fully infectious days. This estimate of mean infectivity is equivalent to calculating the human component of malarial R0. We also predict that mean daily infectivity exceeds five percent for approximately 138 days. The mechanistic framework described herein, made available as stand-alone software, will enable investigators to conduct detailed studies into theories of malaria control, including the effects of drug treatment and drug resistance on transmission

Shots Fired, Shots Refused: Scientific, Ethical & Legal Challenges Surrounding the U.S. Military\u27s COVID-19 Vaccine Mandate

The COVID-19 pandemic provided uncertain and challenging circumstances under which to lead a nation and the military that protects it. Those in charge and in command faced unique challenges—scientific, ethical, and legal—at our various levels of government to both keep people safe while keeping government and society functioning. While there were many successes to celebrate, there are also many criticisms for how this “whole-of-government approach” may have degraded some of our most cherished liberties along the way. The authors focus on the U.S. military’s vaccine mandate and propose military leaders may have failed to fully consider the evolving science, weigh the prevailing ethics, and appropriately apply the relevant law regarding exemptions, and instead adopted a more uniform approach that aligned with other federal agencies and not to the military’s unique population. And along the way, military leaders lost some of the trust and the faith of those they were seeking to protect, prompting the other two branches of government, the Judiciary and Congress, to intervene. Drawing from our diverse experiences as both practitioners and academics, this Article not only seeks to document the past but also provides some suggestions for the future should we face another such pandemic

Shots Fired, Shots Refused: Scientific, Ethical & Legal Challenges Surrounding the U.S. Military\u27s COVID-19 Vaccine Mandate

The COVID-19 pandemic provided uncertain and challenging circumstances under which to lead a nation and the military that protects it. Those in charge and in command faced unique challenges—scientific, ethical, and legal—at our various levels of government to both keep people safe while keeping government and society functioning. While there were many successes to celebrate, there are also many criticisms for how this “whole-of-government approach” may have degraded some of our most cherished liberties along the way. The authors focus on the U.S. military’s vaccine mandate and propose military leaders may have failed to fully consider the evolving science, weigh the prevailing ethics, and appropriately apply the relevant law regarding exemptions, and instead adopted a more uniform approach that aligned with other federal agencies and not to the military’s unique population. And along the way, military leaders lost some of the trust and the faith of those they were seeking to protect, prompting the other two branches of government, the Judiciary and Congress, to intervene. Drawing from our diverse experiences as both practitioners and academics, this Article not only seeks to document the past but also provides some suggestions for the future should we face another such pandemic