UV line diagnostics of accretion disk winds in cataclysmic variables

The IUE data base is used to analyze the UV line shapes of cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating bi-conical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the disk and boundary layer and treats 3-D line radiation transfer in the Sobolev approximation. It is found that winds from accretion disks provide a good fit for reasonable parameters to the observed UV lines which include the P Cygni profiles for low inclination systems and pure emission at large inclination. Disk winds are preferable to spherical winds which originate on the white dwarf because they (1) require a much lower ratio of mass loss rate to accretion rate and are therefore more plausible energetically, (2) provide a natural source for a bi-conical distribution of mass outflow which produces strong scattering far above the disk leading to P Cygni profiles for low inclination systems, and pure line emission profiles at high inclination with the absence of eclipses in UV lines, and (3) produce rotation broadened pure emission lines at high inclination

Rotating Winds from Accretion Disks in Cataclysmic Variables: Eclipse Modeling of V347 Puppis

We study the eclipsing nova-like variable V347 Pup by matching its UV emission line profiles in and out of eclipse to synthetic lines using a 3D kinematic and radiation transfer model. Our results support the accretion disk origin of winds in non-magnetic CVs as opposite to the WD origin. Our main point concerns the importance of rotation for the UV emission line shapes in such systems. In particular, we show that the narrowing of the UV emission lines in V347 Pup during eclipse can be easily explained by the eclipse of the innermost part of the wind by the secondary and the resulting reduction in the contribution of rotational broadening to the width of the lines. During the eclipse, the residual line flux is very sensitive to the maximal temperature of disk radiation. Good fits for reasonable mass-loss rates have been obtained for maximum disk temperatures of 50,000 degrees. This constraint was imposed either by leveling off the inner disk temperature profiles, in agreement with recent observations of some nova-like objects, or by assuming that the accretion disk does not extend to the surface of the white dwarf, in which case V347 up would be an intermediate polar. In anticipation of high-speed spectrophotometry of CVs by the HST, we provide numerical model of a time-resolved eclipse of V347 Pup or similar such system to be verified by future observations.Comment: x pages, postscrip, compressed uuencoded. 11 figures available by anonymous ftp from ftp://asta.pa.uky.edu/shlosman/puppis/ (get *.PS.Z). To appear in Ap

A mobile water disinfection unit powered by renewable energy systems

The current method of disinfection of water used by the United States Army requires a significant amount of mobilization and demobilization time as well as being energy intensive. In an effort to improve small unit mobility a need for a light-weight, low maintenance, highly mobile disinfection system has arisen. In addition to the potential military use, a system of this type could provide a safe drinking water product during the aftermath of natural or man-made disasters, reducing the burden on emergency management services. A prototype system was developed that is self-powered, has low maintenance requirements, and can be stored for extended periods of time without requiring special storage of hazardous materials. Power was provided to the system using a hybrid renewable energy system consisting of a wind turbine and photovoltaic array. The energy generated from the renewable energy system was stored using an ultracapacitor. Disinfection of water was achieved using an ultraviolet disinfection unit. The prototype unit was field tested to evaluate the energy capability and disinfection effectiveness. The results of field testing demonstrated the feasibility of such a system, but several recommendations for modification of the system became apparent. The primary modification would be the removal of the wind turbine which was determined to be redundant, as the PV array provided sufficient energy to the system --Abstract, page iv

“EVERYTHING TEEMING WITH LIFE”: A CRITICAL EXAMINATION OF THOMAS ECCLESHARE’S PASTORAL

Unlike most apocalyptic stories, Thomas Eccleshare’s play, Pastoral, flips the genre on its head with its original take on what could come of the relationship between humans and nature. Throughout the course of the play, readers follow along as an elderly woman, Moll, and her companions attempt to make sense of their new ecologically lavish environment. Rather than humankind dominating nature, Eccleshare posits the question of what could happen if nature dominated over man. Pastoral is a play in which the countryside has become intrepidly abundant; however, rather than providing for humankind, nature attacks it. Set near a shopping center an hour away from London, the play takes us into a fictional reality, making readers and viewers alike wonder if the relationship between humans and nature really is stable. Contemporary fiction, drama, and poetry often contain apocalyptic themes as writers and readers struggle with the concept of the world ending or changing drastically in some form. It often takes a “human versus nature” form. Among the numerous works of apocalyptic and dystopian literature showing a world ravaged by humankind’s harsh hand lies Eccleshare’s first play. This play is unlike other contemporary pieces of literature in that it reverses the “human versus nature” binary. By doing this, Eccleshare presents the consequence to the destruction humans have committed. In Pastoral, nature, not humans, is responsible for the destruction. The play is intriguing to watch as well as read, and since it was first performed only this year1, scholarship has yet to explore this unique take on the relationship between nature and humankind. In this paper, I will explore Pastoral using ecocriticism, gender theory, and performance theory to determine how nature is viewed by the characters in the play as well as how they react to nature’s furious destruction. The three theories intersect in the play by bringing to light the ways in which the characters struggle with making sense of the destruction as well as how the ecocrisis affects each character’s societal role. Ecocriticism, gender theory, and performance theory can all be applied to Pastoral because evidence can be found within the text. I will draw from scholarship on post-apocalyptic literature and theatre reviews to offer some insights to this play’s contribution to the genre

U.S.-Taiwan Relations: A Study on the Taiwan Relations Act

The relationship between the United States and Taiwan is of great importance to both parties. Taiwan offers certain strategic opportunities for the promotion of American national security interests, and the U.S. accordingly provides Taiwan with support of both a defensive and diplomatic nature. The official U.S. policies regarding relations with Taiwan are enumerated in the Taiwan Relations Act (United States Code Title 22 Chapter 48 Sections 3301 - 3316). The act, approved by the U.S. Congress in 1967, stipulates the terms of the bilateral relationship with regard to national defense and diplomatic relations among other factors. This paper seeks to obtain a more developed picture of sentiments on both sides of this relationship in order to understand better the U.S.\u27s influence and power in Taiwan and in the region

Tactile suppression and visual attention: Effects on tactile discrimination performance

The aim was to investigate tactile discrimination performance under various active and passive conditions and explore the influence of visual information. Participants had to discriminate the direction of lateral pin strokes on their fingertip under three conditions. In one condition (“static”) only tactile stimulation was provided. In a second condition (“active”) the shear force device was mounted on a kinesthetic feedback device so that tactile stimulation was accompanied by active arm movements. In a third condition (“passive”) the arm was moved passively using the kinesthetic device while subjects performed the discrimination task. In this first experiment vision was not controlled. Therefore, to investigate the influence of vision on tactile discrimination performance participants had to perform the tactile discrimination task in the “active” condition with either direct gaze on their hand, gaze on a live image of their hand or without sight of their hand. Results show that tactile discriminatio n performance was higher in the “static” compared to the “active” condition. Moreover, participants performed better when they were gazing on their hand compared to the no-sight condition. We conclude that active movement impairs tactile discrimination performance. However visual spatial attention can compensate to some degree for this loss of tactile sensibility

Resolving Semantic Ambiguities in Sentences: Cognitive Processes and Brain Mechanisms

fMRI studies of how the brain processes sentences containing semantically ambiguous words have consistently implicated (i) the left inferior frontal gyrus (LIFG) and (ii) posterior regions of the left temporal lobe in processing high-ambiguity sentences. This article reviews recent findings on this topic and relates them to (i) psycholinguistic theories about the underlying cognitive processes and (ii) general neuro-cognitive accounts of the relevant brain regions. We suggest that the LIFG plays a general role in the cognitive control process that are necessary to select contextually relevant meanings and to reinterpret sentences that were initially misunderstood, but it is currently unclear whether these control processes should best be characterised in terms of specific processes such as conflict resolution and controlled retrieval that are required for high-ambiguity sentences, or whether its function is better characterised in terms of a more general set of ‘unification’ processes. In contrast to the relatively rapid progress that has been made in understanding the function of the LIFG, we suggest that the contribution of the posterior temporal lobe is less well understood and future work is needed to clarify its role in sentence comprehension