3,927 research outputs found
Removing Orbital Debris with Lasers
Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the
use of LEO space is threatened by runaway collisional cascading. A problem
predicted more than thirty years ago, the threat from debris larger than about
1 cm demands serious attention. A promising proposed solution uses a high power
pulsed laser system on the Earth to make plasma jets on the objects, slowing
them slightly, and causing them to re-enter and burn up in the atmosphere. In
this paper, we reassess this approach in light of recent advances in low-cost,
light-weight modular design for large mirrors, calculations of laser-induced
orbit changes and in design of repetitive, multi-kilojoule lasers, that build
on inertial fusion research. These advances now suggest that laser orbital
debris removal (LODR) is the most cost-effective way to mitigate the debris
problem. No other solutions have been proposed that address the whole problem
of large and small debris. A LODR system will have multiple uses beyond debris
removal. International cooperation will be essential for building and operating
such a system.Comment: 37 pages, 15 figures, in preparation for submission to Advances in
Space Researc
Riparian buffer design tool for cropland: lotic systems
Non-Peer ReviewedRiparian areas function as a buffer between the upland and the aquatic systems. This area is
unique in its structure and the services it provides intercepting non-point source (NPS) pollution
from the upland. In some cases additional buffer width may be required or sought. Riparian
buffer strips are a beneficial management practice (BMP) eligible for cost-shared funding under
government programs. However, little information is available to assist landowners in
appropriate location or design considerations. This project aims to create a riparian buffer design
tool to be utilized on lotic (flowing water) systems in cropland settings. This tool will consist of
a flow chart and accompanying key. The flow chart along with air photographs, soils maps and
discussions with the landowner will help to determine where on the landscape a buffer should be
located. The final product will include case studies and guiding documents for technical staff to
utilize when assisting landowners with their riparian buffer strips
Geodynamics of the eastern sector of the Arrábida chain (W Portugal)
N.º4, p.263-267The Arrábida chain - located in the southern segment of the Lusitanian basin - is a S-wards directed fold and thrust belt of Miocene age of deformation. ENE-WSW striking frontal ramps and associated folds are connected to sinistral NNE-SSW and N-S striking lateral ramps, that show left-lateral and SE-wards reverse movements. Both frontal and oblique ramps form imbricate duplexes. Constriction increases SE-wards due to the presence of a basin boundary fault (SetúbaI- Pinhal Novo fault) that acts as a buttress to the oblique thrust movement. Kilometre scale transpressive structures can be observed along the basin boundary fault. A map scale sheath fold like structure can be observed at the Viso anticline, which is a consequence of a strong anisotropy contrast of the Mesocenozoic strata.The Arrábida chain thrusts migrated backward, i.e. to the north, according to an overstep model. Detailed geometrical reconstruction and kinematic analysis of the structures of the eastern region of Arrábida (Formosinho, Vise and Serra de S. Luis anticlines) show that a thin-skinned tectonic model (Ribeiro, A. et aI., 1990) fits very well with the geometry of the structures of the Arrábida chain
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MoonLITE – Technological feasibility of the penetrator concept
Introduction: While the surface missions to the Moon of the 1960s and 1970s achieved a great deal, scientifically a great deal was also left unresolved. The recent plethora of lunar missions (flown or proposed) reflects resurgence in interest in the Moon, not only in its own right, but also as a record of the formation of the Earth-Moon System and the interplanetary environment at 1 AU. Results from orbiter missions have indicated the possible presense of ice within permanently shaded craters at the lunar poles [1] – a situation that, if confirmed, will have profound impacts on lunar exploration
Violent and victimized bodies: sexual violence policy in England and Wales
This paper uses the notion of the body to frame an archaeology of sexual violence policy in England and Wales, applying and developing Pillow’s ideas. It argues that the dominant construction is of sexual violence as an individualized crime, with the solution being for a survivor to report, and with support often instrumentalized in relation to criminal justice objectives. However, criminal justice proceedings can intensify or create further trauma for sexual violence survivors. Furthermore, in addition to criminalizing the violent body and supporting the victimized one, there is a need for policy to produce alternative types of bodies through preventative interventions. Much sexual violence is situated within (hetero) sexual dynamics constructing a masculine aggressor and a feminine body which eventually yields. Prevention must therefore focus on developing embodied boundaries, and narratives at the margins of policy could underpin such efforts
Autofluorescence lifetime augmented reality as a means for real-time robotic surgery guidance in human patients.
Due to loss of tactile feedback the assessment of tumor margins during robotic surgery is based only on visual inspection, which is neither significantly sensitive nor specific. Here we demonstrate time-resolved fluorescence spectroscopy (TRFS) as a novel technique to complement the visual inspection of oral cancers during transoral robotic surgery (TORS) in real-time and without the need for exogenous contrast agents. TRFS enables identification of cancerous tissue by its distinct autofluorescence signature that is associated with the alteration of tissue structure and biochemical profile. A prototype TRFS instrument was integrated synergistically with the da Vinci Surgical robot and the combined system was validated in swine and human patients. Label-free and real-time assessment and visualization of tissue biochemical features during robotic surgery procedure, as demonstrated here, not only has the potential to improve the intraoperative decision making during TORS but also other robotic procedures without modification of conventional clinical protocols
'Lad culture' in higher education: agency in the sexualisation debates
This paper reports on research funded by the National Union of Students, which explored women students’ experiences of ‘lad culture’ through focus groups and interviews. We found that although laddism is only one of various potential masculinities, for our participants it dominated social and sexual spheres of university life in problematic ways. However, their objections to laddish behaviours did not support contemporary models of ‘sexual panic’, even while oppugning the more simplistic celebrations of young women’s empowerment which have been observed in debates about sexualisation. We argue that in their ability to reject ‘lad culture’, our respondents expressed a form of agency which is often invisibilised in sexualisation discussions and which could be harnessed to tackle some of the issues we uncovered
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