79,503 research outputs found
Reply to Comment by Galapon on 'Almost-periodic time observables for bound quantum systems'
In a recent paper [1] (also at http://lanl.arxiv.org/abs/0803.3721), I made
several critical remarks on a 'Hermitian time operator' proposed by Galapon [2]
(also at http://lanl.arxiv.org/abs/quant-ph/0111061).
Galapon has correctly pointed out that remarks pertaining to 'denseness' of
the commutator domain are wrong [3]. However, the other remarks still apply,
and it is further noted that a given quantum system can be a member of this
domain only at a set of times of total measure zero.Comment: 3 page
Radiobiological studies with monoenergetic neutrons
The Radiological Research Accelerator Facility (RARAF) has the capability of
producing essentially monoenergetic neutron beams, ranging in energy from 16.4 MeV
down to 220 keV. In addition, two lower energy neutron beams are available which
consist of a wide spectrum of energies and are described as the 110 keV and 60 keV
spectra. Seedlings of Vicia faba have been used to measure the oxygen enhancement
ratio (OER) and the relative biological effectiveness (RBE) of each of these neutron
beams. The OER decreases as the neutron energy is reduced between 15.4 MeV and
220 keV, but does not appear to decrease further for lower energy neutrons. RBE increases
as the neutron energy is reduced from 15.4 AleV to 440 keV; the curve then
goes through a maximum at around 350 keV, and for lower energies the RBE falls again
Recent developments in the application of risk analysis to waste technologies.
The European waste sector is undergoing a period of unprecedented change driven
by business consolidation, new legislation and heightened public and government
scrutiny. One feature is the transition of the sector towards a process industry
with increased pre-treatment of wastes prior to the disposal of residues and the
co-location of technologies at single sites, often also for resource recovery
and residuals management. Waste technologies such as in-vessel composting, the
thermal treatment of clinical waste, the stabilisation of hazardous wastes,
biomass gasification, sludge combustion and the use of wastes as fuel, present
operators and regulators with new challenges as to their safe and
environmentally responsible operation. A second feature of recent change is an
increased regulatory emphasis on public and ecosystem health and the need for
assessments of risk to and from waste installations. Public confidence in waste
management, secured in part through enforcement of the planning and permitting
regimes and sound operational performance, is central to establishing the
infrastructure of new waste technologies. Well-informed risk management plays a
critical role. We discuss recent developments in risk analysis within the sector
and the future needs of risk analysis that are required to respond to the new
waste and resource management agenda
Field Release of Virus-Sprayed Adult Parasitoids of the European Pine Sawfly (Hymenoptera: Diprionidae) in Wisconsin
Rapid field release of adult parasitoids sprayed with the nucleopolyhedrosis virus of the European pine sawfly successfully transferred the virus to feeding larval colonies
Comparison of Material Properties and Microstructure of Specimens Built Using the 3D Systems Vanguard HS and Vanguard HiQ+HSSLS Systems
The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new control software. The paper compares
the tensile modulus, tensile strength, elongation at break, flexural modulus, Izod impact resistance and microstructure of two batteries of standard specimens built from recycled Duraform
PA (Nylon 12). The first set is built on a Vanguard HS system and the second on the same
system with the HiQ upgrade installed. The upgrade reduces user intervention, decreases total build time and improves surface finish. However, using the default processing parameters,
tensile, flexure and impact properties are all found to decline after the upgrade is installed.Mechanical Engineerin
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