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Abstract In this work addition of ethanol to high viscosity jatropha methyl ester (JME) through port injection is investigated in order to determine its effect fuel viscosity reduction on diesel engine performance. In addition to viscosity alteration, the impact of ethanol addition on combustion characteristics such as combustion duration, ignition delay and emissions levels from diesel engines fuelled with blends of ethanol, diesel and JME is studied in particular. It is found that blending of oxygenated fuels with diesel modifies the chemical structure and physical properties which again alter the engine operating conditions, combustion parameters and emissions levels. However, the injection of only 5% ethanol through port injection allows for a total of 25% blending of biofuels into diesel yet keeping the fuel characteristics close to that of conventional diesel. However, both experimental and numerical results show that ethanol addition in JME blended diesel results in a slight increase in fuel consumption and thermal efficiency for the same power outputs as that of conventional diesel fuel. Also, the combustion characteristics with ethanol addition include improved maximum in-cylinder peak pressure, cumulative heat release (CHR) rate of heat release (ROHR), in-cylinder peak temperature and combustion duration. Regarding emission characteristics the experimental results show significant reduction in smoke, carbon monoxide (CO) and total hydrocarbon (THC) emissions with extended oxygen mass percentage in the fuel at higher engine loads. However, oxides of nitrogen (NOx) emissions are found to increase at high loads although the common tradeoff between smoke and NOx is found to be more prominent for the oxygenated fuels.

Abstract In this work addition of ethanol to high viscosity jatropha methyl ester (JME) through port injection is investigated in order to determine its effect fuel viscosity reduction on diesel engine performance. In addition to viscosity alteration, the impact of ethanol addition on combustion characteristics such as combustion duration, ignition delay and emissions levels from diesel engines fuelled with blends of ethanol, diesel and JME is studied in particular. It is found that blending of oxygenated fuels with diesel modifies the chemical structure and physical properties which again alter the engine operating conditions, combustion parameters and emissions levels. However, the injection of only 5% ethanol through port injection allows for a total of 25% blending of biofuels into diesel yet keeping the fuel characteristics close to that of conventional diesel. However, both experimental and numerical results show that ethanol addition in JME blended diesel results in a slight increase in fuel consumption and thermal efficiency for the same power outputs as that of conventional diesel fuel. Also, the combustion characteristics with ethanol addition include improved maximum in-cylinder peak pressure, cumulative heat release (CHR) rate of heat release (ROHR), in-cylinder peak temperature and combustion duration. Regarding emission characteristics the experimental results show significant reduction in smoke, carbon monoxide (CO) and total hydrocarbon (THC) emissions with extended oxygen mass percentage in the fuel at higher engine loads. However, oxides of nitrogen (NOx) emissions are found to increase at high loads although the common tradeoff between smoke and NOx is found to be more prominent for the oxygenated fuels.

Air is a desirable alternative to the less environmental friendly SF6 in compact medium voltage switchgear. However, the poor thermal properties of air requires better thermal designs to keep the temperature rise within the allowable industry limits to avoid premature switch degradation. This publication focuses on the temperature rise of load break switches (LBS) of different designs. A LBS with flexible braid was found to have considerably higher temperature rise than a design with the sliding contact. The study has shown that a stripped switch (with only the current path) can be used together with empirical determined heat transfer coefficients in a first approach for predicting the temperature rise of the critical parts of the LBS. Aluminum construction elements functioning as heat sinks had a huge impact on the temperature rise of the LBS, and design elements that can utilize this might be important when replacing SF6 with air.

Air is a desirable alternative to the less environmental friendly SF6 in compact medium voltage switchgear. However, the poor thermal properties of air requires better thermal designs to keep the temperature rise within the allowable industry limits to avoid premature switch degradation. This publication focuses on the temperature rise of load break switches (LBS) of different designs. A LBS with flexible braid was found to have considerably higher temperature rise than a design with the sliding contact. The study has shown that a stripped switch (with only the current path) can be used together with empirical determined heat transfer coefficients in a first approach for predicting the temperature rise of the critical parts of the LBS. Aluminum construction elements functioning as heat sinks had a huge impact on the temperature rise of the LBS, and design elements that can utilize this might be important when replacing SF6 with air.

Abstract Partial least square regression (PLS-R) methodology have been applied on dataset containing FTIR spectra and densities for a large set of MEA solvent samples. The prediction capabilities for the major compounds were tested on different set of realistic degraded solvent samples ranging from bench scale experiments to pilot plant campaigns. Generally, the methods showed good results with exception of samples with high amount of heat stabile salts (HSS). For the real samples, sample residuals (i.e. part of data not fitted by the model) were also studied, and a clear correlation between the residuals and HSS level in samples were observed. Online techniques based on PLS-R and FTIR should be an attractive alternative for monitoring the major solvent compounds in CO2 capture plants using amine solvents, as this will reduce cost of chemical analysis and could be an important tool for implementation of control strategies for energy saving in the process.

Abstract Partial least square regression (PLS-R) methodology have been applied on dataset containing FTIR spectra and densities for a large set of MEA solvent samples. The prediction capabilities for the major compounds were tested on different set of realistic degraded solvent samples ranging from bench scale experiments to pilot plant campaigns. Generally, the methods showed good results with exception of samples with high amount of heat stabile salts (HSS). For the real samples, sample residuals (i.e. part of data not fitted by the model) were also studied, and a clear correlation between the residuals and HSS level in samples were observed. Online techniques based on PLS-R and FTIR should be an attractive alternative for monitoring the major solvent compounds in CO2 capture plants using amine solvents, as this will reduce cost of chemical analysis and could be an important tool for implementation of control strategies for energy saving in the process.

AbstractEuropean climate is associated with variability and changes in the mid-latitude atmospheric circulation. In this study, we aim to investigate potential future change in circulation over Europe by using the EURO-CORDEX regional climate projections at 0.11° grid mesh. In particular, we analyze future change in 500-hPa geopotential height (Gph), 500-hPa wind speed and mean sea level pressure (MSLP) addressing different warming levels of 1 °C, 2 °C and 3 °C, respectively. Simple scaling with the global mean temperature change is applied to the regional climate projections for monthly mean 500-hPa Gph and 500-hPa wind speed. Results from the ensemble mean of individual models show a robust increase in 500-hPa Gph and MSLP in winter over Mediterranean and Central Europe, indicating an intensification of anticyclonic circulation. This circulation change emerges robustly in most simulations within the coming decade. There are also enhanced westerlies which transport warm and moist air to the Mediterranean and Central Europe in winter and spring. It is also clear that, models showing different responses to circulation depend very much on the global climate model ensemble member in which they are nested. For all seasons, particularly autumn, the ensemble mean is much more correlated with the end of the century than most of the individual models. In general, the emergence of a scaled pattern appears rather quickly.