Submillimeter observations of solar limb-brightening in the total solar eclipse of 31 July 1981

Eight flights of the Kuiper Airborne Observatory (KAO) were devoted to solar observation. The successful observation of a total solar eclipse was accomplished. The observations were made simultaneously at 30, 50, 100, and 200 microns. The successful adaptation of the KAO for solar observations thus provided the most detailed data to date in this spectral band. The results from a preliminary analysis of the KAO data are summarized: (1) the 200 micron limb is extended about 3 arc sec above the 30 micron limb, indicating the prescence of cool dense material up to the altitudes of spicules; (2) strong radial darkening of the quiet sun intensity profile appeared at 200 microns, probably an indication that hot material in the low chromosphere is recessed into vertical magnetic flux tubes embedded in a cooler nonmagnetic substrate, which obscures the heated material approaching the limb; (3) active regions were observed to undergo a strong increase in contrast above the quiet sun background at wave lengths of 100 microns and longer; and (4) the moon was mapped for use as a photometric standard for determining the absolute intensity of the sun in all four wavelength bands

Extreme limb profiles of the sun at far-infrared and submillimeter wavelengths

Thirty, 50, 100, and 200 microns solar limb intensity profiles determined with arcsecond resolution from airborne observations of the occultation of the solar limb during the total eclipse of 1981 July 31 are presented. Two points of particular importance emerge: (1) the longer-wavelength (100 and 200 micron) limbs are significantly brighter than disk center. At 200 microns the extreme limb is about 1.22 times the brightness of disk center. This is consistent with the 6000 K temperature-plateau structure of the model chromospheres of Vernazza, Avrett, and Loeser (1973, Ap. J., 184, 605; 1981; Ap. J. Suppl., 45, 635;) and (2) the longer wavelength limbs are extended significantly further above the visible limb than Vernazza, Avrett, and Loeser predict. These results provide a strong basis for modeling of the solar chromosphere free from the assumption of gravitational-hydrostatic equilibrium

Submillimeter extensions of the solar limb determined from observations of the total eclipse of 1981 July 31

First results are presented of observations of a lunar occultation of the solar limb made from the Kuiper Airborne Observatory in the 30 micrometr, 50 micrometer, 100 micrometer, and 200 micrometer continuum during the total solar eclipse of 1981 July 31. The solar limb was extended at the longer wavelengths up to 1000 km higher than predicted from smooth plane-parallel chromospheric models. Results at both second and third contact show the infrared limb extensions to be approximately 0".8, 1"5, 2".5 and 3".0 above the visible limb in the observed bands, respectively. A possible interpretation proposes chromospheric fine structure inhomogeneities of greater density than presently incorporated in models of the middle chromosphere

Advanced secondary power system for transport aircraft

A concept for an advanced aircraft power system was identified that uses 20-kHz, 440-V, sin-wave power distribution. This system was integrated with an electrically powered flight control system and with other aircraft systems requiring secondary power. The resulting all-electric secondary power configuration reduced the empty weight of a modern 200-passenger, twin-engine transport by 10 percent and the mission fuel by 9 percent

Playful interactions: A critical inquiry into interactive art and play

My practice-based doctoral research explores how I, as an artist, can create conditions and possibilities for playful interaction in and around interactive artworks. Using practice- based research methods four artworks were created, presented and examined in relation to my research questions concerning play. The three key research questions were:1] How do the properties and affordances of materials and technologies foster play and interactions?2] How can artists conceptualise physical participation and play in interactive artworks? 3] What kind of play takes place in and around interactive artwork?My inquiry focused on the development of a model for making playful and interactive artworks and the creation of a vocabulary of play, which demonstrates the different kinds of play initiated through my practice and research. The model provides alternative ways to think about the role of play within interactive art and consists of a series of tangible making gambits for eliciting playful interactions from the audience. The model will be useful for future interactive artists, as well as other fields concerned with the creation of playful experiences. Underpinning my process of creating playful experiences were methods of observation of the participants’ interactions, which were used in order to enable change and improvement of the artworks throughout the research process.I argue that by employing a sculptural approach to interactive art, using the visual arts tradition of working with the properties of materials and affordances of technology, an invitation to play was created. I propose that to focus on the material’s affordance, rather than on interactive systems, provides additional ways to create interactivity. I also suggest that by understanding technology as a sculptural and embodied material we can move the focus from the technology to what the art does and says. In this sculptural playful interactivity audience members are allowed and encouraged to touch and physical and immersive participation is invited. I explored the body as a particular mode of interaction that can bridge the divide between doing and looking in the gallery, developing theories of the playful body and how audiences connect through play. I argue that the combination of sculptural, captivating interfaces, where the artwork reacts reliably, enables the audience to develop play mastery and become fully engaged. These playful interactions invite people to be curious and seek to engage audiences into dialogue, thereby opening up the possibility for play. Play is an essential pre-condition for the emergence of possibilities and, as such, it is the flexible structure by which meaningful interaction can arise. These interactions are not about our relation to technology but rather about new ways of experiencing culture. In this context interactive art is part of a wider change in contemporary art, where artists are creating culture to be experienced rather than consumed

Treatment options for recurrent glioblastoma: a network meta-analysis

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:. To evaluate the effectiveness of further treatment/s for first and subsequent recurrence of glioblastoma multiforme (GBM) among people who have received the standard of care for primary treatment of the disease (chemoradiotherapy) or following development of GBM from a lower grade (radiotherapy with subsequent temozolomide at relapse); and to prepare a brief economic commentary on the available evidence

Water Footprint and Life Cycle Assessment as approaches to assess potential impacts of products on water consumption: Key learning points from pilot studies on tea and margarine

Water accounting and environmental impact assessment across the product's life cycle is gaining prominence. This paper presents two case studies of applying the Life Cycle Assessment (LCA) and Water Footprint (WF) approaches to tea and margarine. The WF, excluding grey water, of a carton of 50 g tea is 294 L green water and 10 L blue water, and that of a 500 g tub of margarine is 553 L green water, 109 L blue water. The inventory results in the LCA studies (blue water) are 13 L for tea and 114 L for margarine. In the impact assessment phase of WF, Coonoor in Southern India appears as a potential hotspot for tea production, although the water consumed in energy to boil the kettle and by the consumer are also significant. For margarine the main potential hotspot is irrigated sunflower around Zaporizhia in Ukraine. The impact assessment results of LCA for tea causes the water in the consumer use phase to be down-weighted and stresses the contribution from Coonoor due to the higher water scarcity of this region. Similarly the LCA impact assessment of margarine causes the palm oil contribution to be down-weighted due to the low water scarcity of Medan in Indonesia. From these case studies we identify similarities, differences and synergies at both the water accounting and impact assessment levels for both approaches with the purpose of improving and advancing the water resource assessment process

A Coherence-Based Approach for Tracking Waves in the Solar Corona

We consider the problem of automatically (and robustly) isolating and extracting information about waves and oscillations observed in EUV image sequences of the solar corona with a view to near real-time application to data from the Atmospheric Imaging Array (AIA) on the Solar Dynamics Observatory (SDO). We find that a simple coherence / travel-time based approach detects and provides a wealth of information on transverse and longitudinal wave phenomena in the test sequences provided by the Transition Region and Coronal Explorer (TRACE). The results of the search are "pruned" (based on diagnostic errors) to minimize false-detections such that the remainder provides robust measurements of waves in the solar corona, with the calculated propagation speed allowing automated distinction between various wave modes. In this paper we discuss the technique, present results on the TRACE test sequences, and describe how our method can be used to automatically process the enormous flow of data (~1Tb/day) that will be provided by SDO/AIA after launch in late 2008.Comment: 34 pages, 16 figures - in press Solar Physic

Atomic level termination for passivation and functionalisation of silicon surfaces

Chemical treatments play an essential role in the formation of high quality interfaces between materials, including in semiconductor devices, and in the functionalisation of surfaces. We have investigated the effects of hydrogen and fluorine termination of (100)-orientation silicon surfaces over a range of length scales. At the centimetre scale, lifetime measurements show clean silicon surfaces can be temporarily passivated by a short treatment in both HF(2%) : HCl(2%) and HF(50%) solutions. The lifetime, and hence surface passivation, becomes better with immersion time in the former, and worse with immersion time in the latter. At the nanometre scale, X-ray photoelectron spectroscopy and atomic force microscopy show treatment with strong HF solutions results in a roughened fluorine-terminated surface. Subsequent superacid-derived surface passivation on different chemically treated surfaces shows considerably better passivation on surfaces treated with HF(2%) : HCl(2%) compared to HF. Lifetime data are modelled to understand the termination in terms of chemical and field effect passivation at the centimetre scale. Surfaces passivated with Al2O3 grown by atomic layer deposition behave similarly when either HF(2%) : HCl(2%) or HF(50%) are used as a pre-treatment, possibly because of the thin silicon dioxide interlayer which subsequently forms. Our study highlights that chemical pre-treatments can be extremely important in the creation of high quality functionalised surfaces

Predictability of large future changes in a competitive evolving population

The dynamical evolution of many economic, sociological, biological and physical systems tends to be dominated by a relatively small number of unexpected, large changes (`extreme events'). We study the large, internal changes produced in a generic multi-agent population competing for a limited resource, and find that the level of predictability actually increases prior to a large change. These large changes hence arise as a predictable consequence of information encoded in the system's global state.Comment: 10 pages, 3 figure