Optical observation of "band‐to‐band" scattering by time‐resolved phosphorescence line narrowing: Exciton dephasing in a quasi‐one‐dimensional solid

Abstract Unavailable

Schleiermacher and Otto on religion : a reappraisal

An interpretation of the work of Schleiermacher and Otto recently offered by Andrew Dole, according to which these two thinkers differed over the extent to which religion can be explained naturalistically, and over the sense in which the supernatural can be admitted, is examined and refuted. It is argued that there is no difference between the two thinkers on this issue. It is shown that Schleiermacher's claim that a supernatural event is at the same time a natural event does not invite, but rather forecloses the possibility of, a naturalistic explanation of the event. It is further demonstrated that Otto, like Schleiermacher, denied the existence of supernatural events interpreted as events that infringe the laws of nature

From buildings to cities: techniques for the multi-scale analysis of urban form and function

The built environment is a significant factor in many urban processes, yet direct measures of built form are seldom used in geographical studies. Representation and analysis of urban form and function could provide new insights and improve the evidence base for research. So far progress has been slow due to limited data availability, computational demands, and a lack of methods to integrate built environment data with aggregate geographical analysis. Spatial data and computational improvements are overcoming some of these problems, but there remains a need for techniques to process and aggregate urban form data. Here we develop a Built Environment Model of urban function and dwelling type classifications for Greater London, based on detailed topographic and address-based data (sourced from Ordnance Survey MasterMap). The multi-scale approach allows the Built Environment Model to be viewed at fine-scales for local planning contexts, and at city-wide scales for aggregate geographical analysis, allowing an improved understanding of urban processes. This flexibility is illustrated in the two examples, that of urban function and residential type analysis, where both local-scale urban clustering and city-wide trends in density and agglomeration are shown. While we demonstrate the multi-scale Built Environment Model to be a viable approach, a number of accuracy issues are identified, including the limitations of 2D data, inaccuracies in commercial function data and problems with temporal attribution. These limitations currently restrict the more advanced applications of the Built Environment Model

Characterization of vibrational overtones and "local" modes by emission spectroscopy

Abstract unavailable

Combustion instability sustained by unsteady vortex combustion

The determination of an internal feedback mechanism which leads to combustion instability inside a small scale laboratory combustor is presented in this paper. During combustion instability, the experimental findings show that a large vortical structure is formed at an acoustic resonant mode of the system. The subsequent unsteady burning, within the vortex as it is convected downstream, feeds energy into the acoustic field and sustains the large resonant oscillations. These vortices are formed when the acoustic velocity fluctuation at the flameholder is a large fraction of the mean flow velocity. The propagation of these vortices is not a strong function of the mean flow speed and appears to be dependent upon the frequency of the instability. Continued existence of large vortical structures which characterize unstable operation depends upon the fuel-air ratio, system acoustics, and fuel type