Pollutant dispersion by tall buildings: laboratory experiments and Large-Eddy Simulation.

Abstract: Pollutant dispersion by a tall-building cluster within a low-rise neighbourhood of Beijing is investigated using both full-scale Large-Eddy Simulation and water flume experiments at 1:2400 model-to-full scale with Particle Image Velocimetry and Planar Laser-Induced Fluorescence. The Large-Eddy Simulation and flume results of this realistic test case agree remarkably well despite differences in the inflow conditions and scale. Tall buildings have strong influence on the local flow and the development of the rooftop shear layer which dominates vertical momentum and scalar fluxes. Additional measurements using tall-buildings-only models at both 1:2400 and 1:4800 scales indicates the rooftop shear layer is insensitive to the scale. The relatively thicker incoming boundary layer affects the Reynolds stresses, the relative size of the pollutant source affects the concentration statistics and the relative laser-sheet thickness affects the spatially averaged results of the measured flow field. Low-rise buildings around the tall building cluster cause minor but non-negligible offsets in the peak magnitude and vertical location, and have a similar influence on the velocity and concentration statistics as the scale choice. These observations are generally applicable to pollutant dispersion of realistic tall building clusters in cities. The consistency between simulations and water tunnel experiments indicates the suitability of both methodologies.

[Determination of vertical dimension of dental occlusion]. / Beethoogtebepaling in een gemutileerde dentitie.

Principles and concepts in determining the vertical dimension of occlusion in mutilated dentitions are summarized. Historically, most concepts have been developed for full dentures. However, in the rehabilitation of a mutilated dentition it is often necessary to increase or change the vertical dimension of occlusion. If the vertical dimension of occlusion has to be altered the patient's adaptability to the new position should be tested during a trial period. Determination of the vertical dimension of occlusion is apparently a combination of art, science and experience.

Making an alternative occlusal splint.

An occlusal splint is commonly used in the diagnosis and management of temporomandibular disorders. In a partially edentulous patient a poorly adapted removable partial denture can prevent the use of a conventional occlusal splint. This article describes the fabrication of an occlusal splint that also incorporates a provisional removable partial denture.