Abstract

The need for sustainable biofuels has initiated a global search for innovative technologies that can sustainably convert nonfood bioresources to liquid transportation fuels. While 2nd generation cellulosic ethanol has begun to address this challenge, other resources including yellow and brown grease are rapidly evolving commercial opportunities that are addressing regional biodiesel needs. This review examines the technical and environmental factors driving the collection of trap FOG (Fats, Oils, and Greases), its chemical composition and technologies currently available and future developments that facilitate the conversion of FOG into biodiesel.

Abstract

International audience; The widespread increase in the use of light emitting diodes in vehicle's head and taillights and also the use of dashboard cameras provides great prospects for the optical camera based visible light communications (VLC) technology in intelligent transport systems. In this paper, we experimentally investigate the impact of fog on the optical camera based VLC technology for vehicle-to-vehicle (V2V) communications. A range of meteorological visibilities between 5-120 m is considered based on realistic inter-vehicle distances in practical vehicular environments and using a real car taillight as the transmitter. We show a reduction in the index of modulation of the signals from 1 to 0.75 and 0.5 to allow for tracking purposes of the light source when sending '0' symbols. The results show that, the link is error-free up to 20 m meteorological visibility for the three modulation index scenarios and degrades considerably below 10 m meteorological visibility.

Abstract

Fog is a hazardous weather phenomenon, which can impact traffic (especially air traffic) and air quality. The aim of this study is to analyse fog climatology, the trends of long-term changes of fog events and factors affecting them in general, in Latvia, but especially in Riga airport. For a 50-year period of observations, the analysis of the fog frequencies, long-term changes and atmospheric conditions favourable for the occurrence of fog events in Latvia has been studied. During the analysis two inter-annual maxima of fog frequency were found in spring and autumn, and the seasonal differences in the formation of fog were also approved by the satellite data on low cloud cover.