ABSTRACT
A study on the measurement of visibility by the use of light scattering has been carried out. The basis for the research was the optical forward-scatter sensor, Mira visibility sensor, developed and produced by Aanderaa Instruments. The focus of the study was on how to measure correct visibility at different weather situations (e.g. fog, rain, haze and snow) and how a sensor can provide information on the type of particles/drops which are causing reduced visibility. Optical scatter measurement of airborne dust was also investigated. The work includes theoretical calculations and experimental work. The correlations between scatter measurements and both visibility and the concentration of airborne dust are studied. A short introduction to the subject of visibility measurement is also included.
Subject(s)
Air Pollutants/analysis , Biosensing Techniques , Environmental Monitoring/methods , Scattering, Radiation , Vision, Ocular/physiology , Cities , Diagnostic Techniques, Ophthalmological , Dust/analysis , Environmental Monitoring/instrumentation , Research DesignABSTRACT
In this paper we postulate and solve the following problem: Prove in the framework of Newtonian mechanics that three Coulomb charges (-1,Q,Q) for Q>4 will leave any initial volume in a finite time and estimate this time. We also discuss possible generalizations of the problem and its relation to stability of ions and molecules.
