13,086 research outputs found
Introduction
Crime-preventing neurointerventions (CPNs) are increasingly being used or advocated for crime prevention. There is increasing use of testosterone-lowering agents to prevent recidivism in sexual offenders, and strong political and scientific interest in developing pharmaceutical treatments for psychopathy and anti-social behaviour. Recent developments suggest that we may ultimately have at our disposal a range of drugs capable of suppressing violent aggression, and it is not difficult to imagine possible applications of such drugs in crime prevention. But should neurointerventions be used in crime prevention, and may the state ever permissibly impose CPNs as part of the criminal justice process? It is widely thought that preventing recidivism is one of the aims of criminal justice, yet existing means of pursuing this aim are often poorly effective, restrictive of basic freedoms, and harmful. Incarceration, for example, tends to be disruptive of personal relationships and careers, detrimental to physical and mental health, highly restrictive of freedom of movement and association, and rarely more than modestly effective at preventing recidivism. Neurointerventions hold the promise of preventing recidivism in ways that are more effective and more humane, but the use of CPNs in criminal justice raises several ethical concerns. CPNs could be highly intrusive and may threaten fundamental human values, such as bodily integrity and freedom of thought, and humanity has a track record of misguided, harmful, and unwarrantedly coercive use of neurotechnological ‘solutions’ to criminality. This collection brings together original contributions from emerging scholars and internationally renowned moral and political philosophers to address these issues
Semi-analytical approach to short-wavelength dispersion and modal properties of photonic crystal fibers
We consider photonic crystal fibers made from arbitrary base materials and
derive a unified semi-analytical approach for the dispersion and modal
properties which applies to the short-wavelength regime. In particular we
calculate the dispersion and the effective index and comparing to
fully-vectorial plane wave simulations we find excellent agreement. We also
calculate asymptotic results for the mode-field diameter and the V-parameter
and from the latter we predict that the fibers are endlessly single mode for a
normalized air-hole diameter smaller than 0.42, independently of the base
material.Comment: 3 pages including 3 figures. Accepted for Opt. Let
Investigation into the role of sodium chloride deposited on oxide and metal substrates in the initiation of hot corrosion
Sodium chloride is deposited on the surface of alumina substrates and exposed to air containing 1% SO2 at temperatures between 500 C and 700 C. In all cases the sodium chloride was converted to sodium sulfate. The volatilization of sodium chloride from the original salt particles was responsible for the development of a uniform coating of sodium sulfate on the alumina substrate. At temperatures above 625 C, a liquid NaCl-Na2SO4 autectic was formed on the substrate. The mechanisms for these reactions are given. One of the main roles of NaCl in low temperature hot corrosion lies in enabling a corrosive liquid to form
Localization of light on a cone: theoretical evidence and experimental demonstration for an optical fiber
The classical motion at a conical surface is bounded at one (narrower) side
of the cone and unbounded at the other. However, it is shown here that a
dielectric cone with a small half-angle gamma can perform as a high Q-factor
optical microresonator which completely confines light. The theory of the
discovered localized conical states is in excellent agreement with experimental
data. It provides both a unique approach for extremely accurate local
characterization of optical fibers (which usually have gamma ~10^-5 or less)
and a new paradigm in the field of high Q-factor resonators
Two-dimensional photonic band-gap structures as quasi-metals
By considering waves that propagate out of the transverse plane, we show that common high index materials (eg GaAs) with a 2D array of air holes can act in some ways like a 3D photonic band-gap structure. In particular, we describe a dielectric "quasi-metal" that reflects all propagating light incident from free space
Streamlined life cycle assessment of transparent silica aerogel made by supercritical drying
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierWhen developing sustainable building fabric technologies, it is essential that the energy use and CO2 burden arising from manufacture does not outweigh the respective in-use savings. This study investigates this paradigm by carrying out a streamlined life cycle assessment (LCA) of silica aerogel. This unique, nanoporous translucent insulation material has the lowest thermal conductivity of any solid, retaining up to four times as much heat as conventional insulation, whilst being highly transparent to light and solar radiation. Monolithic silica aerogel has been cited as the ‘holy grail’ of future glazing technology. Alternatively, translucent granular aerogel is now being produced on a commercial scale. In each case, many solvents are used in production, often accompanied by intensive drying processes, which may consume large amounts of energy and CO2. To date, there has been no peer-reviewed LCA of this material conducted to the ISO 14000 standard. Primary data for this ‘cradle-to-factory gate’ LCA is collected for silica aerogel made by low and high temperature supercritical drying. In both cases, the mass of raw materials and electricity usage for each process is monitored to determine the total energy use and CO2 burden. Findings are compared against the predicted operational savings arising from retrofitting translucent silica aerogel to a single glazed window to upgrade its thermal performance. Results should be treated as a conservative estimate as the aerogel is produced in a laboratory, which has not been developed for mass manufacture or refined to reduce its environmental impact. Furthermore, the samples are small and assumptions to upscale the manufacturing volume occur without major changes to production steps or equipment used. Despite this, parity between the CO2 burden and CO2 savings is achieved in less than 2 years, indicating that silica aerogel can provide a measurable environmental benefit.This work is funded by the EPSRC, Brunel University and Buro Happold Ltd, the University of Bath is funded by the EPSRC grant EP/F018622/1
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