Energy-Harvesting Mechanisms for UAV Flight by Dynamic Soaring

Dynamic Soaring is a flying technique which extracts energy from an environment where wind gradients form, with the potential to increase the endurance of small unmanned vehicles. The feasibility to use dynamic soaring flight is questioned here; it requires the identification of energy-extraction mechanisms as well as accurate understanding of the way energy-harvesting performances are governed by trajectory constraints, vehicle characteristics and environment conditions. A three-dimensional energy-neutral trajectory is derived out of a specified optimization problem. Characteristic phases of flight are evidenced out of an overall closed trajectory. Simplified equations are used to evidence the physics behind energy transfers. Finally, overall energy-harvesting balance is studied through local variations of total energy along the path

The First Three Rungs of the Cosmological Distance Ladder

It is straightforward to determine the size of the Earth and the distance to the Moon without making use of a telescope. The methods have been known since the 3rd century BC. However, few amateur or professional astronomers have worked this out from data they themselves have taken. Here we use a gnomon to determine the latitude and longitude of South Bend, Indiana, and College Station, Texas, and determine a value of the radius of the Earth of 6290 km, only 1.4 percent smaller than the true value. We use the method of Aristarchus and the size of the Earth's shadow during the lunar eclipse of 2011 June 15 to derive an estimate of the distance to the Moon (62.3 R_Earth), some 3.3 percent greater than the true mean value. We use measurements of the angular motion of the Moon against the background stars over the course of two nights, using a simple cross staff device, to estimate the Moon's distance at perigee and apogee. Finally, we use simultaneous CCD observations of asteroid 1996 HW1 obtained with small telescopes in Socorro, New Mexico, and Ojai, California, to derive a value of the Astronomical Unit of (1.59 +/- 0.19) X 10^8 km, about 6 percent too large. The data and methods presented here can easily become part of a beginning astronomy lab class.Comment: 34 pages, 11 figures, accepted for publication in American Journal of Physic

Парсическая роль интеллигенции в истории

In 1661, Borelli and Ecchellensis published a Latin translation of a text which they called the Ltmmas of Archimedes. The first fifteen propositions of this translation correspond to the contents of the Arabic Book of Assumptions, which the Arabic tradition attributes to Archimedes. The work is not found in Greek and the attribution is uncertain at best. Nevertheless, the Latin translation of the fifteen propositions was adopted as a work of Archimedes in the standard editions and translations by Heiberg, Heath, Ver Eecke and others. Our paper concerns the remaining two propositions, 16 and 17, in the Latin translation by Borelli and Ecchellensis, which are not found in the Arabic Book of Assumptions. Borelli and Ecchellensis believed that the Arabic Book of Assumptions is a mutilated version of a lost "old book" by Archimedes which is mentioned by Eutodus (ca. A.D. 500) in his commentary to Proposition 4 of Book 2 of Archimedes' On the Sphere and Cylinder. This proposition is about cutting a sphere by a plane in such a way that the volumes of the segments have a given ratio. Because the fifteen propositions in the Arabic Book of Assumptions have no connection whatsoever to this problem, Borelli and Ecchellensis "restored" two more propositions, their 16 and 17. Propositions 16 and 17 concern the problem of cutting a given line segment AG at a point X in such a way that the product AX· XG2 is equal to a given volume K. This problem is mentioned by Archimedes, and although he promised a solution, the solution is not found in On the Sphere and Cylinder. In his commentary, Eutodus presents a solution which he adapted from the "old book" of Archimedes which he had found. Proposition 17 is the synthesis of the problem by means of two conic sections, as adapted by Eutodus. Proposition 16 presents the diorismos: the problem can be solved only if K::::;;; AB · BG2, where point B is defined on AG such that AB = 1/zBG. We will show that Borelli and Ecchellensis adapted their Proposition 16 not from the commentary by Eutocius but from the Arabic text On Filling the Gaps in Archimedes' Sphere and Cylinder which was written by Abu Sahl al-Kuru in the tenth century, and which was published by Len Berggren. Borelli preferred al-Kiihi's diorismos (by elementary means) to the diorismos by means of conic sections in the commentary of Eutocius, even though Eutocius says that he had adapted it from the "old book." Just as some geometers in later Greek antiquity, Borelli and Ecchellensis bdieved that it is a "sin" to use conic sections in the solution of geometrical problems if elementary Euclidean means are possible. They (incorrectly) assumed that Archimedes also subscribed to this opinion, and thus they included their adaptation of al-Kuru's proposition in their restoration of the "old book" of Archimedes. Our paper includes the Latin text and an English translation of Propositions 16 and 17 of Borelli and Ecchellensis

The Power of Words

Presenter will share unit starting with readings in which writers and leaders describe the importance of literacy despite racism, peer pressure, and poverty. Students engage in lessons exploring their struggles, making comparisons to their own literary histories, and writing a thematic essay on the Power of Words. Presentation includes interactive activity and sharing of high school and FYW students\u27 work

The Genetic Basis of Alzheimer\u27s Disease: Phenotype-Genotype Relationship in Autosomal-Dominant Alzheimer\u27s Disease

From the Washington University Office of Undergraduate Research Digest (WUURD), Vol. 12, 05-01-2017. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences. Mentor: Tammie Benzinge

Primary Cilia in Cardiac Valve Development and Disease

Cardiac valve disease is a major health burden affecting around 5% of the population. Two of the most common cardiac valve disease include mitral valve prolapse (MVP) and bicuspid aortic valve disease (BAV). Currently treatment options consist of invasive surgeries to either repair or replace the damages valve tissues. Evidence suggests that both MVP and BAV are congenital diseases that present complications in patients later in life. Treatment options for these diseases are lacking due to an incomplete understanding of the molecular causes. Mitral valve prolapse (MVP) is one of the most common forms of cardiac valve disease and affects ~2-3% of the human population. MVP can lead to secondary complications such as arrhythmias, heart failure, and sudden cardiac death and 1 in 10 patients will require valve surgery. There are no effective nonsurgical treatments for MVP and therapeutic efforts have been hindered by an incomplete understanding of its fundamental causes. One accessible source of such information may come from genetic studies of MVP. We previously reported familial and GWAS studies that identified genetic mutations and/or excellent candidate targets as causal to MVP. Pathway analyses suggested a common cellular and molecular thread between these studies and invoke the primary cilia as potential unifying mechanism. This discovery is further bolstered by our recent identification of a mutation in a cilia gene in a large family with MVP, DZIP1. Our data show genetic haploinsufficiency of primary cilia in cardiac valves leads to a non-syndromic mitral valve disease in mouse models whereas complete genetic ablation enhances mitral valve phenotype severity and generation of bicuspid aortic valve (BAV). We present, for the first time, a potential common cellular and molecular thread through which MVP and potentially BAV can arise. These studies define the primary cilia as a critical, and previously unrecognized facet of cardiac valve development. Uncovering how valve disease genes regulate downstream signaling cascades will provide key mechanistic insights into MVP and potentially BAV pathogenesis at a cellular and molecular level

Avondale

A copy of a brochure detailing Avondale history and real estate options. Likely from the 1920\u27