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Publications

Publications by CESE

2014

Can hydrogen or natural gas be alternatives for aviation? - A life cycle assessment

Authors
Pereira, SR; Fontes, T; Coelho, MC;

Publication
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

Abstract
Between 1989 and 2011 the aviation traffic has been growing 4.6% per year. The increase on aviation traffic had consequences in terms of greenhouse gases (GHGs) and local pollutant emissions (e.g. carbon monoxide - CO, hydrocarbons - HC, nitrogen oxides - NOx). In order to minimize this problem, the evaluation of sustainable alternatives to current fuel (jet fuel A) has been discussed but their impact on emissions is still unclear. The main research goals of this paper are: (i) to evaluate if the well-to-wake energy consumption in aviation can be reduced with alternative fuels as liquid natural gas (LNG) and/or liquid hydrogen (LH2) and (ii) to assess if alternative fuels can be used in aviation to minimize carbon dioxide emissions and local pollutants. In this analysis two types of flights were evaluated: short flights (<5000 km) and long flights (>5000 km) for six typical aircrafts. We verified that LH2 from SMR can provide between 13% and 21% less environmental and social impacts than jet fuel A, in the same aircraft. Copyright

2014

Emissions impact of road traffic incidents using Advanced Traveller Information Systems in a regional scale

Authors
Fontes, T; Lemos, A; Fernandes, P; Pereira, SR; Bandeira, JM; Coelho, MC;

Publication
17TH MEETING OF THE EURO WORKING GROUP ON TRANSPORTATION, EWGT2014

Abstract
Advanced Traveller Information Systems (ATIS) have been used worldwide to mitigate different road traffic impacts such as traffic congestion. However, the impact of these systems in fuel use and emissions is still an important research topic, due to their non-linear behaviour. Therefore, this paper aims to evaluate the impact of traffic incidents on a regional scale on energy and emissions levels. To achieve these objectives, several scenarios assessing different degrees of information (through the use of ATIS) were analysed. To model both traffic operations and emissions a mesoscopic traffic model (DTALite) and a road emissions methodology (EMEP/EEA) were used. The data related to the characterization of the road network was collected between Oporto and Aveiro, in Portugal. To ensure reliable results, the traffic model was calibrated and validated taking into account statistical methods that compare observed traffic flows and travel times with the values estimated by the model. The simulation platform was then used to assess the impact of traffic incident when it occurs in two different road types (a motorway and a highway), in order to evaluate the impact of usage and availability of information on emissions and fuel consumption. The results show that in a regional road network for each occurred incident, the use of ATIS can allow a maximum reduction of emissions and energy consumption on those routes where they occurred to up 2%. Nonetheless, a global analysis of the network indicates different results depending if the incident occur in a motorway or in a highway. In both cases, drivers tend to choose a route with similar costs to the previously selected. Furthermore, a non-linear trend between the availability of information and the impact on emissions and energy consumption was found. (C) 2014 Published by Elsevier B.V.

2014

Impact assessment of road fleet transitions on emissions: The case study of a medium European size country

Authors
Fontes, T; Pereira, SR;

Publication
ENERGY POLICY

Abstract
This paper aims to examine the impacts of fleet composition changes on emission due to the introduction of different road transportation policies in a medium size European country (Portugal) applying an ex-post analysis (e.g. policies based on fuel pricing, car scraping, car taxation). A baseline scenario was compared with a counterfactual scenario in order to understand what would occur in the absence of the introduction of those policies. For each scenario, four approaches were assessed using economic effects and/or human health costs. HC, CO, NOx, PM and CO2 emissions from passenger cars and light duty vehicles were evaluated. The results show high statistical significance (p <= 0.05) between CO emissions and different vehicle features as vehicle age, fuel type and engine classes. The same pattern was observed between the average vehicle age and HC, NOx and PM. After the implementation of road traffic policies, the average emission factors of the fleet decreased 28-62% for HC, CO, NOx, PM and 20-39% for CO2. However, if a counterfactual scenario would be implemented, the reduction would be 20-80% and 26-55% higher, respectively. The results demonstrates that although were recorded some benefits, the fleet characteristics distribution were more environmental friendly in 2001 than in 2011.

2014

Learning from 24 years of ozone data in Portugal

Authors
Barros, N; Silva, MP; Fontes, T; Manso, MC; Carvalho, AC;

Publication
WIT Transactions on Ecology and the Environment

Abstract
Ozone (O3) is a secondary pollutant mainly produced in the troposphere by photochemical reactions with high impact on human health. In this work hourly average O3 concentrations from the Portuguese air quality network collected during 24 years (1988–2011) were analysed. The background time series were assessed by environment type (urban, suburban and rural) and considering several criteria: the annual mean O3 concentration, the Directive 2008/50/EC O3 long-term objective and the 2005 WHO Guideline for protection of human health and, finally, the hourly information threshold exceedances. The trend of annual mean O3 concentration data and the maximum daily eight-hour mean ozone concentration data were both annually compared using an one-way ANOVA followed by a Tamhane post-hoc comparison test. In both series, although of an instable trend, a tendency for an increase of the mean O3 concentrations was found. On the other hand, after 2006, for all stations types, the normalized number of exceedances for public O3 information are significantly decreasing (p<0.05). In this paper, the O3 trend will be analyzed and discussed, contributing to improve knowledge of long time series of O3 concentrations in Portugal. © 2014 WIT Press.

2014

10.5937/fmet1403243s = Representational fidelity in distributed and remote lab environment

Authors
Spasojevic-Brkic, V; Putnik, G; Veljkovic, Z; Shah, V; Castro, H;

Publication
FME Transaction

Abstract

2014

Dashboard services for pragmatics-based interoperability in cloud and ubiquitous manufacturing

Authors
Ferreira, L; Putnik, G; Cruz Cunha, MM; Putnik, Z; Castro, H; Alves, C; Shah, V;

Publication
International Journal of Web Portals

Abstract
The real Cloud and Ubiquitous Manufacturing systems require effectiveness and permanent availability of resources, their capacity and scalability. One of the most important problems for applications management over cloud based platforms, which are expected to support efficient scalability and resources coordination following SaaS implementation model, is their interoperability. Even application dashboards need to easily incorporate those new applications, their interoperability still remains a big problem to override. So, the possibility to expand these dashboards with efficiently integrated communicational cloud based services (cloudlets) represents a relevant added value as well as contributes to solving the interoperability problem. Following the architecture for integration of enriched existing cloud services, as instances of manufacturing resources, this paper: a) proposes a cloud based web platform to support dashboard integrating communicational services, and b) describe an experimentation to sustain the theory that the effective and efficient interoperability, especially in dynamic environments, could be achieved only with human intervention. Copyright © 2014, IGI Global.

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