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Abstract. The impact of multiphase reactions involving nitrogen dioxide (NO2) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism) was applied for the aqueous phase reactions, whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 µm and a liquid content (LC) of 50 µg m-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO2 with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may increase gas phase HONO levels under some conditions and that the extent of this effect is strongly pH dependent. Especially under moderate acidic conditions (i.e. pH above 4) this source may represent more than 75% of the total HONO/NO2 - production rate, but this contribution drops down close to zero in acidic droplets (as those often encountered in urban environments).

United Nation’s sustainable goals place emphasis on renewable energy resources to transform the world into a sustainable one and enable it to have affordable energy. Of late alternative green fuels are becoming promising sources of fuel to address the energy crisis. Waste cooking oil (WCO) is the raw material used for biodiesel preparation, which can be employed as a fuel in compression ignition (CI) engines. This article investigates the dual impact of biodiesel, a green fuel and a renewable green additive (turpentine oil) on the performance and emissions of a CI engine. The studies were performed using a B20 (20% biodiesel + 80% diesel) WCO biodiesel fuel blend with 2.5% and 5% vol. of turpentine oil as an additive. The outcome of this research showed an improvement in brake thermal efficiency for the B20 biodiesel blend with a 5% turpentine oil additive. Turpentine oil additive promoted more complete combustion and produced lower carbon monoxide (CO), hydrocarbon (HC) and smoke emissions. However, the oxides of nitrogen (NOx) emissions increased as the turpentine oil composition increased from 2.5% to 5%, which is 4.5% more than B20. The outcome of this study can be extended to accomplish the objectives of sustainable development goal 7 (affordable and clean energy) and goal 13 (climate action) which are planned to be achieved by 2030.

This research examines the economic implications of different designs for a national low carbon fuel standard (NLCFS) for the road transportation sector. A NLCFS based on the average Carbon Intensity (CI) of all fuels sold generates an incentive for fuel suppliers to reduce the measured CI of their fuels. The economic impacts are determined by the availability of low carbon fuels, estimates of which can vary widely. Also important are the compliance path, reference level CI, and the design of the credit system, particularly the opportunities for trading and banking. To quantitatively examine the implications of a NLCFS, we created the Transportation Regulation and Credit Trading (TRACT) Model. With TRACT, we model a NLCFS credit trading system among profit maximizing fuel suppliers for light- and heavy-duty vehicle fuel use for the United States from 2012 to 2030. We find that credit trading across gasoline and diesel fuel markets can lower the average costs of carbon reductions by an insignificant amount to 98% depending on forecasts of biofuel supplies and carbon intensities. Adding banking of credits on top of trading can further lower the average cost of carbon reductions by 5%–9% and greatly reduce year-to-year fluctuations in credit prices.

SignificanceMarginal emissions of CO2from the electricity sector are critical for evaluating many climate policies. We provide estimates of marginal CO2emissions for electricity use in the United States that vary by region, hour of day, and year to year. Despite a decrease in average emissions over the last decade, marginal emissions have increased. We apply our estimates to an analysis of the Biden administration’s target of having electric vehicles make up 50% of new vehicle purchases by 2030. We find that, without significant and concurrent changes to the electricity sector far more substantial than those over the last decade, the increase in electricity emissions is likely to offset more than half the emission reductions from having fewer gasoline-powered vehicles.

Abstract A recent field survey provided eight typical soffits used in the residential houses within the typhoon-prone coastal region of southeastern China. Their aerodynamic effects in alleviating rooftop extreme wind pressures were evaluated via wind tunnel testing on a series of 1/20 gable roof house models. Local pressures, area-averaged pressures and uplift forces acting on roofs were examined. Results showed that in contrast to the model without soffits, the presence of these gutters or eaves gives a rise to a significant reduction of negative peak wind pressures at edges and corners near them. However, they hardly impact wind loads on the other roof surface. Some minor simple architectural elements attached to eaves, such as cantilevered spoiler and semicircular gutter, were observed to facilitate the reduction of extreme wind pressure at edges and corners. Additionally, the reduction rate of spatially averaged wind pressures with area was found to be dependent on the size of tributary area, rather than the shape of tributary area.

Abstract This literature review was built upon recently published articles on Life Cycle Assessments (LCAs) of agricultural biogas plants, to: enhance understanding of the relevant literature in the field and the related question by readers worldwide. It was designed to highlight methodological issues and impact indicators, which best represent this research field; consequently, they should be considered in performing environmental assessments of agro-biogas derived energy systems. The literature review highlighted the wide variability of environmental results due to the ways the feedstock mixtures were produced, managed, and supplied; and due to the regions in which the anaerobic digesters were located and operated. Differences were found to be related to the aim and function of the study and to the methodological approach used, especially for the development of the environmental impact assessments. Other differences resulted from the ways the energy produced was utilised, whether it was used as an input to the natural gas national grid, and/or if it was used within the production system. The authors of this review concluded that, although much progress has been made, many unsolved challenges and methodological choices must be addressed to further improve the robustness of LCA in relation to AD and to related approaches.

The aim of this research is to find out suitable material for insulator and their flashover performance to withstand the high pollution degree in different environmental conditions. The experimental investigation was carried out on various insulating material like porcelain, glass, and rubber to find out the artificial effluence to examine alternate current flashover potentials. The result shows that the polluted flashover voltage is affected by equivalent salt deposit density and non soluble deposit density, the authorities of which are autonomous of each one on another. The correction formulae of the flashover voltage of various insulators at various salt deposit density and non soluble deposit density levels have pointed out by means of the flashover voltages examination. Also the dissimilarity existing between the flashover voltages of various types of polluted insulators. From this we are able to conclude which insulating material withstands the pollution degree better amongst the above three.