5,486 research outputs found
Immorality and Irrationality
Does immorality necessarily involve irrationality? The question is often taken to be among the deepest in moral philosophy. But apparently deep questions sometimes admit of deflationary answers. In this case we can make way for a deflationary answer by appealing to dualism about rationality, according to which there are two fundamentally distinct notions of rationality: structural rationality and substantive rationality. I have defended dualism elsewhere. Here, Iâll argue that it allows us to embrace a sensible â I will not say boring â moderate view about the relationship between immorality and irrationality: roughly, that immorality involves substantive irrationality, but not structural irrationality. I defend this moderate view, and argue that many of the arguments for less moderate views turn either on missing the distinction between substantive and structural rationality, or on misconstruing it
Rationality as the Rule of Reason
The demands of rationality are linked both to our subjective normative perspective (given that rationality is a person-level concept) and to objective reasons or favoring relations (given that rationality is non-contingently authoritative for us). In this paper, I propose a new way of reconciling the tension between these two aspects: roughly, what rationality requires of us is having the attitudes that correspond to our take on reasons in the light of our evidence, but only if it is competent. I show how this view can account for structural rationality on the assumption that intentions and beliefs as such involve competent perceptions of downstream reasons, and explore various implications of the account
The potential of vortex amplifiers to improve mixture preparation in spark ignition engines.
Spark ignition engines are a significant source of air pollution. Emissions are
most severe in the period after the engine has been started from cold. This is because
fuel enrichment is needed to ensure reliable combustion in the cold cylinder. The
problem is compounded by the exhaust treatment catalyst not reaching operating
temperature until some minutes after starting. As the majority of car usage is for short
journeys, engines spend much of their time in this high emission operating regime.
One route to reducing emissions is to improve mixture preparation. This is
Particularly effective after a cold start as less enrichment is required to ensure
combustion. The aim of this project has been to evaluate a Vortex'Amplifier as a route
to improving mixture preparation.
The vortex amplifier is a no moving parts fluidic control device. It regulates a
large volume supply flow by imparting swirl to it with a small volume control flow.
The control flow vortex creates a region of highly turbulent flow at the device outlet
which possesses the potential to atomise a fuel spray.
The VA has been tested experimentally. The sprays produced by the vortex
amplifier were measured by a laser diffraction technique. Numerical analysis has also
been undertaken to determine the motion of droplets within the vortex chamber and the
potential of the flow to disrupt a fuel spray.
The vortex amplifier has been found to be a highly effective atomiser. It
produces sprays with a Sauter mean diameter approximately half the size of the best current technology. However the spray impacts on the walls of any pipework
downstream of the VA due to the high tangential velocities in the flow exiting the VA.
This problem currently precludes engine us'e, but suggestions for improving the
situation are contained in the recommendations for future work
Structural and magnetic characterization of the complete delafossite solid solution (CuAlO2){1-x}(CuCrO2){x}
We have prepared the complete delafossite solid solution series between
diamagnetic CuAlO2 and the t2g^3 frustrated antiferromagnet CuCrO2. The
evolution with composition x in CuAl(1-x)Cr(x)O2 of the crystal structure and
magnetic properties has been studied and is reported here. The room-temperature
unit cell parameters follow the Vegard law and increase with x as expected. The
effective moment is equal to the Cr^3+ spin-only S = 3/2 value throughout the
entire solid solution. Theta is negative, indicating that the dominant
interactions are antiferromagnetic, and its magnitude increases with Cr
substitution. For dilute Cr compositions, J_BB was estimated by mean-field
theory to be 2.0 meV. Despite the sizable Theta, long-range antiferromagnetic
order does not develop until very large x, and is preceeded by glassy behavior.
Data presented here, and that on dilute Al-substitution from Okuda et al.,
suggest that the reduction in magnetic frustration due to the presence of
non-magnetic Al does not have as dominant an effect on magnetism as chemical
disorder and dilution of the magnetic exchange. For all samples, the 5 K
isothermal magnetization does not saturate in fields up to 5 T and minimal
hysteresis is observed. The presence of antiferromagnetic interactions is
clearly evident in the sub-Brillouin behavior with a reduced magnetization per
Cr atom. An inspection of the scaled Curie plot reveals that significant
short-range antiferromagnetic interactions occur in CuCrO2 above its Neel
temperature, consistent with its magnetic frustration. Uncompensated
short-range interactions are present in the Al-substituted samples and are
likely a result of chemical disorder
Numerical simulation of centrifugal pumps
The power computers increase and the specific calculation software development have made possible, nowadays, the numerical simulation of flow and energy transfer inside the turbomachinery. To teach Fluid Mechanics is not easy not only for the professors but also for the students because the theoretical part must be complemented with a technical part where students can see the phenomena. However, specially in hydraulic turbomachinery, we canĂt see the phenomena except if we have a specific material, for example a PIV. Even if we would have this material, the access to specific parts of turbomachinery is not possible due to its constructive layout. The use of numerical simulation tools allows us to obtain data in inaccessible positions for the experimentation, as well as the study of unusual or dangerous performances. With the numerical simulation, the pressure fluctuation at any point of the pump can be easily obtained. Other important results are the radial forces on the impeller, which have a significant variation with the working points. One of the advantages of this kind of modelling is the ease to carry out changes in the geometry, parametric studies and analysis of anomalous operation conditions
An investigation into the mechanical damping characteristics of catenary contact wires and their effect on aerodynamic galloping instability
Measurement of the damped oscillation of a section of the UK East Coast Main Line (ECML) catenary/contact wire system was undertaken, and the natural frequency and mechanical damping were found to be 1.4Hz and 0.05 respectively. This information was used to assess the effect of increasing the mechanical damping ratio on the susceptibility of the system to an aerodynamic galloping instability. The section of line tested was known to gallop at wind speeds of approximately 40 mile/h, and theoretical and experimental work verified this. A friction damper arm was designed and three units were fitted to the section of line affected. The introduction of increased mechanical damping was found to raise the mechanical damping coefficient of the line to between 0.095 and 0.18, and the mathematical analysis produced a theoretical wind speed for galloping oscillation of between 75 and 141 mile/h respectively. For over a year since the units were fitted, no problems with galloping instability have been observed
Assessment of Satellite-Derived Surface Reflectances by NASAâs CAR Airborne Radiometer over Railroad Valley Playa
CAR (Cloud Absorption Radiometer) is a multi-angular and multi-spectral airborne radiometer instrument, whose radiometric and geometric characteristics are well calibrated and adjusted before and after each flight campaign. CAR was built by NASA (National Aeronautics and Space Administration) in 1984. On 16 May 2008, a CAR flight campaign took place over the well-known calibration and validation site of Railroad Valley in Nevada, USA (38.504°N, 115.692°W). The campaign coincided with the overpasses of several key EO (Earth Observation) satellites such as Landsat-7, Envisat and Terra. Thus, there are nearly simultaneous measurements from these satellites and the CAR airborne sensor over the same calibration site. The CAR spectral bands are close to those of most EO satellites. CAR has the ability to cover the whole range of azimuth view angles and a variety of zenith angles depending on altitude and, as a consequence, the biases seen between satellite and CAR measurements due to both unmatched spectral bands and unmatched angles can be significantly reduced. A comparison is presented here between CARâs land surface reflectance (BRF or Bidirectional Reflectance Factor) with those derived from Terra/MODIS (MOD09 and MAIAC), Terra/MISR, Envisat/MERIS and Landsat-7. In this study, we utilized CAR data from low altitude flights (approx. 180 m above the surface) in order to minimize the effects of the atmosphere on these measurements and then obtain a valuable ground-truth data set of surface reflectance. Furthermore, this study shows that differences between measurements caused by surface heterogeneity can be tolerated, thanks to the high homogeneity of the study site on the one hand, and on the other hand, to the spatial sampling and the large number of CAR samples. These results demonstrate that satellite BRF measurements over this site are in good agreement with CAR with variable biases across different spectral bands. This is most likely due to residual aerosol effects in the EO derived reflectance
The poverty of contractarian moral education
In A Theory of Moral Education, Michael Hand claims that a directive moral education that seeks to persuade children that a particular conception of contractarian morality is justified can be undertaken without falling foul of the requirement not to indoctrinate. In this article, we set out a series of challenges to Handâs argument. First, we argue that Handâs focus on âreasonable disagreementâ regarding the status of a moral conception is a red-herring in this conception. Second, we argue that the endorsement of moral contractarianism and the prohibition on indoctrination pull in different directions: if contractarianism is sound, then teachers or governments should be less worried about indoctrination than Hand suggests. Third, we argue that moral contractarianism is mistaken; teachers should look elsewhere for guidance on the moral norms and principles towards which they should direct their pupils
N incorporation and associated localized vibrational modes in GaSb
We present results of electronic structure calculations on the N-related localized vibrational modes in the dilute nitride alloy GaSb1âxNx. By calculating the formation energies of various possible N incorporation modes in the alloy, we determine the most favorable N configurations, and we calculate their vibrational mode frequencies using density functional theory under the generalized gradient approximation to electron exchange and correlation, including the effects of the relativistic spin-orbit interactions. For a single N impurity, we find substitution on an Sb site, NSb, to be most favorable, and for a two-N-atom complex, we find the N-N split interstitial on an Sb site to be most favorable. For these defects, as well as, for comparison, defects comprising two N atoms on neighboring Sb sites and a N-Sb split interstitial on an Sb site, we find well-localized vibration modes (LVMs), which should be experimentally observable. The frequency of the triply degenerate LVM associated with NSb is determined to be 427.6 cmâ1. Our results serve as a guide to future experimental studies to elucidate the incorporation of small concentrations of N in GaSb, which is known to lead to a reduction of the band gap and opens the possibility of using the material for long-wavelength applications
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