24,523 research outputs found
Future of V/STOL aircraft systems: A survey of opinions
The recent success of the British Harriers in the Falkland Islands conflict vividly underscored the potential of V/STOL aircraft in military operations in a difficult environment. Despite this apparent success of the Harrier, there has been a major decline of V/STOL funding in the research and development budgets of the U.S. government and industry. The recent funding history of V/STOL systems is examined. Responses to a questionnaire which asked the question, Should there be an operational V/STOL aircraft other than the AV-8A and AV-8B in the military aircraft fleet of the U.S.A.? are presented and discussed
Quantitying the Effects of Traffic Calming on Emissions Using on-road Measurement
The objective of this work was to determine the effect of
one form of traffic calming on emissions. Traffic calming
is aimed at reducing average vehicle speeds, especially
in residential neighborhoods, often using physical road
obstructions such as speed bumps, but it also results in
a higher number of acceleration/deceleration events
which in turn yield higher emissions. Testing was
undertaken by driving a warmed-up Euro-1 spark ignition
passenger car over a set of speed bumps on a level
road, and then comparing the emissions output to a noncalmed
level road negotiated smoothly at a similar
average speed. For the emissions measurements, a
novel method was utilized, whereby the vehicle was
fitted with a portable Fourier Transform Infrared (FTIR)
spectrometer, capable of measuring up to 51 different
components in real-time on the road. The results
showed that increases in emissions were much greater
than was previously reported by other researchers using
different techniques. When traffic-calmed results were
compared to a smooth non-calmed road, there were
substantial increases in CO2 (90%), CO (117%), NOx
(195%) and THC (148%). These results form the basis
for a good argument against traffic calming using speed
bumps, especially for aggressive drivers. Slowing traffic
down with speed restrictions enforced by speed
cameras is a more environmentally friendly option
Evaluation of a FTIR Emission Measurement System for Legislated Emissions Using a SI Car
A series of chassis dynamometer test trials were
conducted to assess the performance of a Fourier
Transform Infra Red (FTIR) system developed for
on-road vehicle exhaust emissions measurements.
Trials used a EURO 1 emission compliant SI passenger
car which, alongside the FTIR, was instrumented to
allow the routine logging of engine speed, road speed,
throttle position, air-fuel ratio, air flow and fuel flow in
addition to engine, exhaust and catalyst temperatures.
The chassis dynamometer facility incorporated an
‘industry standard’ measurement system comprising
MEXA7400 gas analyzer and CVS bag sampling which
was the ‘benchmark’ for the evaluation of FTIR
legislated gas-phase emissions (CO, NOx, THC and
CO2) measurements.
Initial steady state measurements demonstrated strong
correlations for CO, NOx and THC (R2 of 0.99, 0.97
0.99, respectively) and a good correlation for CO2 (R2 =
0.92). Subsequent transient and total mass emissions
measurements from replicate samplings of four different
driving cycles (two standard cycles, FTP75 and NEDC,
and two novel cycles based on real-world data collected
in Leeds) also show good response of FTIR and
satisfied agreement between the FTIR and CVS bag
sampling measurements.
In general, the trial results demonstrate that the
on-board FTIR emission measurement system provides
reliable in-journey emissions data
Restorative Justice-Informed Moral Acquaintance: Resolving the Dual Role Problem in Correctional and Forensic Practice
The issue of dual roles within forensic and correctional fields has typically been conceptualized as dissonance—experienced by practitioners— when attempting to adhere to the conflicting ethical requirements associated with client well-being and community protection. In this paper, we argue that the dual role problem should be conceptualized more broadly; to incorporate the relationship between the offender and their victim. We also propose that Restorative Justice (RJ) is able to provide a preliminary ethical framework to deal with this common ethical oversight. Furthermore, we unite the RJ framework with that of Ward’s (2013) moral acquaintance model to provide a more powerful approach—RJ informed moral acquaintance—aimed at addressing the ethical challenges faced by practitioners within forensic and correctional roles
Six-wave mixing: secular resonances in a higher-order mechanism for second-harmonic generation
Spin-charge separation in ultra-cold quantum gases
We investigate the physical properties of quasi-1D quantum gases of fermion
atoms confined in harmonic traps. Using the fact that for a homogeneous gas,
the low energy properties are exactly described by a Luttinger model, we
analyze the nature and manifestations of the spin-charge separation. Finally we
discuss the necessary physical conditions and experimental limitations
confronting possible experimental implementations.Comment: 4 pages, revtex4, 2 eps figure
Comparison of explosion characteristics of Colombian and Kellingley coal
Coal continues to be one of the main fuels used for generation of energy in the UK. Despite government’s plans to decarbonise the energy sector in order to meet GHG emission targets, co-firing of coal and biomass is attractive due to the low investment required and since gas prices remain high, the consumption of coal is still considerable in power generation. Pulverised coal has been known to pose explosion risks since the 19th century. The objective of the present work was to compare the explosibility of two coal samples used in UK power stations which potentially can be used co-fired with biomass. Both samples of coal were fully characterised for their chemical composition as well as particle size and morphology. The 1m3 ISO explosion vessel was used to determine the explosion characteristics: deflagration index (Kst), maximum explosion pressure (Pmax) and minimum explosible concentration (MEC). Flame speeds were also measured. The remaining residues after explosion were also analysed. The results were compared to the explosion characteristics of other types of coal available in the literature. Despite the very similar composition of both fuels, the reactivity of Colombian coal was much higher, with a Kst value of 129 barms-1 as opposed to 73 barms-1 for Kellingley coal (Fig.1). There was significant difference between these two coals as the surface area of Colombian coal was 5 times higher than that of Kellingley coal. There was little difference in the elemental composition, but Colombian coal contained more volatiles and less ash. Thus the results indicate a strong impact of particle surface area and volatile content on the reactivity of coal
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