An analysis of the gust-induced overspeed trends of helicopter rotors

Equations for analyzing the potential gust-induced overspeed tendency of helicopter rotors are presented. A parametric analysis was also carried out to illustrate the sensitivity of rotor angular acceleration to changes in rotor lift, propulsive force, tip speed, and forward velocity

A theoretical and experimental investigation of cylindrical electrostatic probes at arbitrary incidence in flowing plasma

The theory for calculating the current collected by a negatively biased cylindrical electrostatic probe at an arbitrary angle of attack in a weakley ionized flowing plasma is presented. The theory was constructed by considering both random and directed motion simultaneous with dynamic coupling of the flow properties and of the electric field of the probe. This direct approach yielded a theory that is more general than static plasma theories modified to account for flow. Theoretical calculations are compared with experimental electrostatic probe data obtained in the free stream of an arc-heated hypersonic wind tunnel. The theoretical calculations are based on flow conditions and plasma electron densities measured by an independent microwave interferometer technique. In addition, the theory is compared with laboratory and satellite data previously published by other investigators. In each case the comparison gives good agreement

Devotion and Suffering in the Life of Johannes Kepler

Various heroes of Christianity have been celebrated by Protestants for centuries. From followers to devout disciples, Christians have recognized certain individuals as being role models. These people have stood as leaders of the faith and spanned from tax collectors, to fishermen, and even to government authorities. Often overlooked, though, were those who made advancements in the sciences, philosophy, mathematics, and other scholarly fields. In certain professions and studies, Protestants were persecuted and forced to deny their beliefs. Some chose to make what they believed as the center of their motivation which would lead to even greater achievements. Of those people, Johannes Kepler certainly impacted the world with his laws and even when he faced adversity, Kepler held on to his faith and progressed further

VTOL in ground effect flows for closely spaced jets

Results of a series of in ground effect twin jet tests are presented along with flow models for closely spaced jets to help predict pressure and upwash forces on simulated aircraft surfaces. The isolated twin jet tests revealed unstable fountains over a range of spacings and jet heights, regions of below ambient pressure on the ground, and negative pressure differential in the upwash flow field. A separate computer code was developed for vertically oriented, incompressible jets. This model more accurately reflects fountain behavior without fully formed wall jets, and adequately predicts ground isobars, upwash dynamic pressure decay, and fountain lift force variation with height above ground

The Only Game in town: the Relationship Between Drones and the Just War Tradition

Since he first came to Regis University in 2010, Stuart Jenkins has been driven by the question, what is the right thing to do? His desire to extend this inquiry into the subject of war inspired him to understand and evaluate the ethical issues at stake in the national debate about the use of drone. This Senior Honors Thesis explores the relationship between the principles of Just War Theory and the use of drones. It asks, what are the core principles of Just War Theory, and how have they developed over time; and, how does the Just War tradition address the issue of terrorism? It also analyzes the dynamic relationship between Just War Theory and the use of drones, and considers the challenges of applying a set of theoretical standards to the complex and difficult problem posed by counterterrorism, raising various additional questions. These questions include what are the strategic and tactical advantages of drones that inform our moral approach to drone strikes; how does the Obama administration justify the use of drones as an instrument of counterterrorism; and, what are the ethical issues that remain unresolved that are relevant to the evolution to the Just War tradition

Assessing connectivity between MPAs: Selecting taxa and translating genetic data to inform policy

This is the final version of the article. Available from the publisher via the DOI in this record.Connectivity is frequently cited as a vital component of Marine Protected Area (MPA) networks and was formally identified as one of five key principles for marine network design in European waters. Yet, without the ability to demonstrate connectivity, it is impossible to be certain that sites designated within a MPA network do in fact constitute a network, when they may –irrespective of the diversity and rarity of the taxa within them– be in reality a set of unlinked habitats and associated species assemblages. However, the process of assessing connectivity between MPAs, and which taxa to include in assessments of connectivity, is often difficult and can be dependent on a variety of factors that can be outside the control of managers, stakeholders and policymakers. Among the many methods that have been used to assess connectivity, genetic markers are often used to infer connectivity indirectly by estimating the degree of genetic differentiation between populations of a species or by inferring the origin(s) of migrants using assignment methods. While modern molecular methods can be extremely robust and are now routinely used to address conservation issues, genetic data are, to the authors’ knowledge, rarely used to inform designation of MPA networks. In this paper, several biological and methodological factors are highlighted, consideration of which may help to inform the selection of species for assessments of connectivity between MPAs in a network, and this paper suggests ways in which genetic data may be interpreted to inform MPA design and policy.This research was funded by a Natural Environment Research Council UK GW4+ DTP studentship (Grant No. NE/L002434/ 1), Natural England (Ref. PO 904130) and the University of Exeter, and forms part of the PhD of Tom L. Jenkins