Modeling the emissions of a dual fuel engine coupled with a biomass gasifier—supplementing the Wiebe function

There is a growing market demand for small-scale biomass gasifiers that is driven by the economic incentives and the legislative framework. Small-scale gasifiers produce a gaseous fuel, commonly referred to as producer gas, with relatively low heating value. Thus, the most common energy conversion systems that are coupled with small-scale gasifiers are internal combustion engines. In order to increase the electrical efficiency, the operators choose dual fuel engines and mix the producer gas with diesel. The Wiebe function has been a valuable tool for assessing the efficiency of dual fuel internal combustion engines. This study introduces a thermodynamic model that works in parallel with the Wiebe function and calculates the emissions of the engines. This “vis-à-vis” approach takes into consideration the actual conditions inside the cylinders—as they are returned by the Wiebe function—and calculates the final thermodynamic equilibrium of the flue gases mixture. This approach aims to enhance the operation of the dual fuel internal combustion engines by identifying the optimal operating conditions and—at the same time—advance pollution control and minimize the environmental impact.     

First principles of the MameLuke multi-actor modelling framework for land use change, illustrated with a Philippine case study

This paper presents the first principles of the MameLuke framework, an agent-based modelling framework for studying environmental issues and land use and cover change (LUCC). The MameLuke framework enhances the understanding of the relationship between societal processes and LUCC by modelling individual and group decisions and human-environment interactions. The framework allows for the transformation of real-life stories into computerised models following a predetermined sequence. By doing so, the framework allows for a truly integrative approach, because it is not bound to any particular scientific discourse. Even better, the framework enables its users to combine scientific discourses regarding human decisions and behaviour on multiple scales and levels. The agents (actors and locations) in the framework are heterogeneous. This heterogeneity of agent behaviour is established by dividing the agents into categories. If an agent is a member of an agent category or combination of categories, it has access to a defined set of implementable actions. The actions are constructed out of potential option paths (POPs) and potential option nodes (PONs). The whole of POPs represent a theoretical construct of agent behaviour and decisions that the framework user wishes to explore. The POP defines a sequence of PONs. The PON is a transaction interface between an initialising agent and a recipient agent where they exchange material and immaterial capital. This paper explains the basic architecture of the MameLuke framework and shows its applicability with a model of a Philippine case study. This case study concerns the dynamics of migration and deforestation. It is part of a larger study on land use change in the San Mariano watershed area at the forest fringe of the Sierra Madre mountains in the Philippines.     

The Environmental “Risky” Region: Identifying Land Degradation Processes Through Integration of Socio-Economic and Ecological Indicators in a Multivariate Regionalization Model

The economic policy needs to pay increasingly more attention to the environmental issues, which requires the development of methodologies able to incorporate environmental, as well as macroeconomic, goals in the design of public policies. Starting from this observation, this article proposes a methodology based upon a Simonian satisficing logic made operational with the help of goal programming (GP) models, to address the joint design of macroeconomic and environmental policies. The methodology is applied to the Spanish economy, where a joint policy is elicited, taking into consideration macroeconomic goals (economic growth, inflation, unemployment, public deficit) and environmental goals (CO₂, NO _x and SO _x emissions) within the context of a computable general equilibrium model. The results show how the government can “fine-tune” its policy according to different criteria using GP models. The resulting policies aggregate the environmental and the economic goals in different ways: maximum aggregate performance, maximum balance and a lexicographic hierarchy of the goals.     

Methanesulphonic acid (MSA) stratigraphy from a Talos Dome ice core as a tool in depicting sea ice changes and southern atmospheric circulation over the previous 140 years

Firn core methanesulphonic acid (MSA) stratigraphy from Talos Dome (East Antarctica) was compared with anomalies of the satellite-measured sea ice extent (1973–1995) in the Ross Sea and Wilkes Land oceanic sector. In spite of the sparseness of sea ice data, the MSA maxima fit with many positive sea ice anomalies in the Ross Sea. This evidence suggests that marine biogenic activity enhanced by large sea ice cover is an important, but not exclusive, factor in controlling MSA concentration in snow precipitation at Talos Dome. Other than source intensity, differences in regional atmospheric transport mechanisms affect the arrival of MSA-rich aerosol at Talos Dome. To clarify the role of transport processes in bringing biogenic aerosol to Talos Dome, a spectral analysis was applied to the MSA, SOI (South Oscillation Index), and SAM (Southern Annular Mode) record. Synchronicity or phase shift between the chemical signature and atmospheric circulation modes were tested. The variations in the MSA profile have a periodicity of 6.9, 4.9, 3.5, and 2.9 years. The 6.9 and 2.9 year periodicities show a strong positive correlation and are synchronous with corresponding SOI periodicity. This variability could be related to an increase in MSA source intensity (by dimethylsulphide from phytoplanktonic activity) linked to the sea ice extent in the Ross Sea area, but also to an increased strength in transport processes. Both of these factors are correlated with La Niña events (SOI positive values). Furthermore, SAM positive values are related to an increased sea ice extent in the Ross Sea sector and show two main periodicities 3.3 and 3.8 years. These periodicities determine the MSA variability at 3.5 years. However, the effect of intensification of the polar vortex and the consequent reduction in transport process intensity, which reduce the delivery of air masses enriched in MSA from oceanic areas to Talos Dome, make the effect of the SAM on the MSA concentration at Talos Dome less active than the SOI. In this way, snow deposition at the Talos Dome records larger MSA concentration by the combined effects of increased source emissions and more efficient transport processes. The MSA record from Talos Dome can therefore be considered a reliable proxy of sea ice extent when the effect of changes in transport processes in this region of Antarctica is considered. Over the previous 140 years, these conditions occur with a periodicity of 6.9 years.     

Is an environmental management system able to influence environmental and competitive performance? The case of the eco-management and audit scheme (EMAS) in the European union

The EMAS Regulation (Reg 761/01 EC) is EU scheme implemented by the European Commission since 1993 and it is for the implementation of an Environmental Management System (EMS) by any organization. The EMS was originally proposed by the European Commission and by the ISO as the frontrunner of a series of policy tools that enable companies to simultaneously pursue environmental objectives and competitive targets in a synergetic way.Based on the unique dataset of the EVER project, this paper investigates whether or not an EMS implemented within the EMAS Regulation has any effect on firm performance both from an environmental and a competitive point of view. Our econometric analysis shows the positive impact of a well-designed environmental management system on environmental performance and, as a consequence, on technical and organizational innovations. Effects on other competitive variables such as market performance, resource productivity and intangible assets are not strongly supported.     

A design for EoL approach and metrics to favour closed-loop scenarios for products

Recently, environmentally conscious design and extended producer responsibility have become key aspects for companies that need to develop products that are sustainable along their whole life cycle. Design for End of Life (EoL) is a strategy that aims to reduce landfill waste through the implementation of closed-loop product life cycles. It is important to consider disassembly and EoL scenario management as early as the design phase. For these reasons, this paper presents an approach to help designers in the evaluation and subsequent improvement in product EoL performance. The method is based on four innovative EoL indices that compare different EoL scenarios for each product component. In this way, the designer can modify the product structure or the liaisons to maximise the reuse and remanufacture of components as well as material recycling. The presented case studies confirm the validity of the approach in helping designers during the redesign phase of goods and products to reduce the quantity of materials and industrial wastes sent to landfill.     

District heating networks: an inter-comparison of environmental indicators

Environmental Science and Pollution Research - The installation of district heating (DH) systems constitutes an advantage from the energetic, climate, and air quality aspects. However, the...     

Comparison of different probe molecules for the quantification of hydroxyl radicals in aqueous solution

We show that the transformation of benzene into phenol is a more selective probe for the hydroxyl radical than the transformation of nitrobenzene or the generation of 4-hydroxybenzoic acid from benzoic acid. The benzene to phenol system showed adequate performance as a probe upon irradiation of lake water samples and humic acids. We show that the use of nitrobenzene and benzoic acid as hydroxyl probes should be avoided because of poor selectivity. Moreover, all the tested probe molecules underwent important interference by irradiated antraquinone-2-sulphonate, and considerably overestimated the formation of the hydroxyl radicals.     

Leaching and half-life of the herbicide tebuthiuron on a recharge area of Guarany aquifer in sugarcane fields in Brazil

This study was undertaken to evaluate the degradation and mobility of the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N'-dimethylurea) in soil under field conditions, and its potential for leaching and groundwater contamination. A watershed, Espraiado, located over a recharge area in Brazil, was chosen for soil and water studies. At Espraiado, water samples were collected from seven wells at intervals of three months from March 2004 to June 2006 and analyzed for tebuthiuron. Other samples were taken from city wells located outside of the recharge area. To assess the potential movement to the aquifer, tebuthiuron was also applied to trial plots at the recommended label rate of 1.0 kg/ha a.i. in May of 2004, with and without sugarcane coverage, on sandy soil. Soil samples were collected during the years of 2004 and 2005, at depths intervals of 20 cm from soil surface down to 120 cm and analyzed for tebuthiuron at zero, 3, 30, 60, 90, 120, 150, 180, 240, and 300 days after application. There was no clear effect of sugarcane coverage on the tebuthiuron degradation in soils, but it moved faster into the soil where there was no cover. After 180 days there were no measurable residues in the soil, and tebuthiuron was not found below 40 cm depth in any time. Tebuthiuron had a half-life of 20 days under those conditions. No tebuthiuron residue was found in ground water samples at any sampling time.