Experimental analysis of hydrotreated vegetable oil (HVO) and commercial diesel fuel blend characteristics using modified CFR engine

ArticlePerformance parameters of different commercial diesel fuels is a subject of interest for fuel consumers. Fuel retailer Neste recently introduced a new brand of WWFC 5th grade diesel fuel in Baltic market, consisting of diesel fuel and hydrotreated vegetable oil (HVO) blend. Fuel samples have been recently tested on chassis dynamometer, measuring wheel power and torque and in road conditions, measuring fuel consumption. Evaluation of fuel consumption and performance parameters in road or laboratory conditions may yield uncertain results due to complexity of modern automobile engine management and emission reduction systems. To better evaluate the combustion, fuel samples have been tested in modified CFR engine at various intake air pressure, temperature and compression ratio settings. Engine indicated performance parameters and combustion phasing of regular diesel fuel and diesel fuel-HVO blend are presented. Comparing to regular diesel fuel, fuel blend with HVO showed reduced apparent heat release rate (AHRR) during premixed combustion phase at low inlet air temperature and low compression ratio conditions, comparing to regular diesel fuel. Premixed combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature and higher compression ratio conditions. Diffusion controlled combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature, higher compression ratio conditions and supercharged air supply

Mapping Settlements in the Wildland Urban Interface: A Decision Tree Approach

The wildland–urban interface (WUI) is the area where human-built structures intermingle or abut wildland vegetation. Maps of the WUI are important for resource management, particularly related to wildfire mitigation, but are often based on spatially coarse data such as housing counts from census blocks. Here, three decision tree models are used to create maps of human settlements for use in delineating the WUI. The first model uses statistics derived from image objects; the second model uses data related to topography, amenities, and accessibility; and the third model uses all available data. The accuracy of the models was evaluated in terms of the percentage of actual structures that fall within the area delineated as settlements. Overall, the three decision models performed similarly, although the third decision tree model was the best. For delineating settlements, all three decision tree models represent an improvement over a null model and the Radeloff et al. (2005) WUI mapping methodology and perform similar to the Wilmer and Aplet (2005) WUI mapping methodology. The models are also more flexible than many existing models, as they allow users to trade off accuracy and the size of the delineated settlement. The strategies described here can potentially yield improved maps of the WUI over larger areas