This paper provides a detailed literature review of the environmental implications of vehicle platooning, a topic gaining significant attention in transportation. While previous reviews have focused ...on the safety, planning, fuel economy, and microsimulation aspects of platooning, this paper delves into environmental aspects. It identifies a lack of research adopting a holistic approach to transport and environmental benefits and emphasizes the need for further research to enhance vehicle efficiency and improve air quality and health conditions. This study traces the historical evolution of platooning, highlighting the shift in research focus over the decades. It advocates for more research on platooning’s environmental aspects, particularly pollutant emissions and air quality. The primary contributions of this work are threefold and include the following: firstly, it delineates simulation methodologies for platooning and the associated pollutant emissions; secondly, it offers a critical assessment of the existing literature on vehicle emissions, fuel consumption, and energy savings; and thirdly, it illuminates the prospective research challenges within the specialized domain of vehicle platooning.
Here, we demonstrate a strategy to convert the graded Michaelis–Menten response typical of unregulated enzymes into a sharp, effectively all-or-none response. We do so using an approach analogous to ...the “branch point effect”, a mechanism observed in naturally occurring metabolic networks in which two or more enzymes compete for the same substrate. As a model system, we used the enzymatic reaction of glucose oxidase (GOx) and coupled it to a second, nonsignaling reaction catalyzed by the higher affinity enzyme hexokinase (HK) such that, at low substrate concentrations, the second enzyme outcompetes the first, turning off the latter’s response. Above an arbitrarily selected “threshold” substrate concentration, the nonsignaling HK enzyme saturates leading to a “sudden” activation of the first signaling GOx enzyme and a far steeper dose–response curve than that observed for simple Michaelis–Menten kinetics. Using the well-known GOx-based amperometric glucose sensor to validate our strategy, we have steepen the normally graded response of this enzymatic sensor into a discrete yes/no output similar to that of a multimeric cooperative enzyme with a Hill coefficient above 13. We have also shown that, by controlling the HK reaction we can precisely tune the threshold target concentration at which we observe the enzyme output. Finally, we demonstrate the utility of this strategy for achieving effective noise attenuation in enzyme logic gates. In addition to supporting the development of biosensors with digital-like output, we envisage that the use of all-or-none enzymatic responses will also improve our ability to engineer efficient enzyme-based catalysis reactions in synthetic biology applications.
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IJS, KILJ, NUK, PNG, UL, UM
In the development of new products, both the use of residues and the use of renewable materials are important strategies for a more circular production. However, it is not enough just to idealize a ...new product as environmentally sustainable, it is also necessary to prove the hypothesis through scientifically accepted methodologies, such as life cycle assessment (LCA). Thus, the objective of this study was to evaluate and compare, through LCA, the environmental performance of two composites reinforced with sisal fibers, one produced with a Portland cement matrix and the other with a geopolymer matrix based on a residue, in this case, the sludge from a water treatment plant. When comparing the environmental performance of composites using the impact assessment methods ReCiPe 2016 Midpoint/Endpoint and EN 15804, the results were convergent; the composite with the cement matrix has less environmental impact. The composite with the Portland cement matrix and 0.4% superplasticizer, for example, in the category Global warming, using the ReCiPe 2016 Midpoint method, was 42.48% less impactful than the geopolymeric composite without the avoided product. In the category Climate change, using the EN 15804 method, the composite with the Portland cement matrix and 0.4% superplasticizer was 42.05% less impactful than the geopolymeric composite without the avoided product. The sensitivity analysis showed that the critical environmental points in the two composites are the production of potassium hydroxide and transport in the case of the geopolymer composite, and the production of cement and transport for the Portland cement composite. This research contributes scientifically by presenting potential alternatives for the construction industry that have already been evaluated from an environmental perspective. It is important to environmentally assess new products still in the development stage, since stating that a building material has superior environmental performance just because it is produced from residues or from a renewable raw material may not be a true reflection of the facts.
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•A comparative cradle-to-gate LCA of two sisal fibers-reinforced composites was performed.•One of the composites was produced with a waste-based geopolymeric matrix, and the other with a Portland cement matrix.•The environmental performance of the composites was evaluated using the ReCiPe 2016 Midpoint and EN15804 methods.•The Portland cement matrix composite had better environmental performance in almost all the impact categories evaluated.•In the geopolymer composite the production of potassium hydroxide is the environmental tipping point.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Atmospheric emissions related to harbor-related activities can significantly contribute to air pollution of coastal urban areas and so, could have implications to the citizens’ health that live in ...those areas. Of great concern is the local impact of the emissions that are generated while ships are at berth, since not all types of ships switch off the main engines. This paper intends to investigate the influence of the stack configuration for generic cargo ships on the exhaust smoke dispersion, using the Port of Leixões as a case study and a series of wind tunnel experiments with support of Particle Image Velocimetry (PIV) technique. For that, different configurations of the stack of a cargo ship (in terms of height, geometry and diameter) were simulated under the typical wind conditions of the study area. The PIV results indicate negligible differences between the medium and long stack height, with the short stack height presenting a strong impact on the flow field around the stack. For the short stack height, the flow field is not only disturbed by the stack, but also by the cargo ship bridge, with both obstacles promoting disturbances on the flow field and creating a large wake turbulence effect, which is important for the downwash phenomena. Regarding the effects linked with two distinct geometries (straight or curved), the results show that the straight chimney led to higher perturbation of wind field when compared with the curved geometry. The curved stack presents an increase of vorticity, indicating the generation of more turbulent structures. The PIV results also confirmed that higher wind velocity at the inlet conducts to higher vorticity levels, as well as a higher number of Kelvin–Helmholtz structures. For distinct wind conditions the PIV measurements point out different patterns, indicating the northern wind direction as the most favorable condition for the exposure of dock workers to pollutants. Overall, the results showed that a ship stack with a curved end, medium length and smaller diameter has the capability to promote the behaviors in the flow that are coherent with increased pollutant dispersion.
A produção de mudas de leucena (Leucaena leucocephala (Lam.) de Witt) é limitada pela dormência das sementes. No presente estudo foram testados diferentes métodos de superação de dormência em ...sementes de leucena, por meio de um experimento em Delineamento Inteiramente Casualizado, com seis tratamentos e quatro repetições. Os tratamentos foram compostos por T0- Controle, T1- imersão em água fria por 24 horas, T2- imersão em água fria por 48 horas, T3- imersão em ácido sulfúrico a 95% por 5 minutos, T4- escarificação mecânica, e T5- imersão em água quente a 60 oC por 15 minutos. Os dados foram analisados no programa estatístico SISVAR e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Os tratamentos por imersão em água à temperatura ambiente por 24 horas ou por 48 horas foram os melhores para a superação de dormência de sementes de leucena.
Palavras-chave: Germinação; escarificação; imersão; leucena.
A linear economic model has proven to lead society into an unsustainable situation. Current policies have been promoting the transition for a circular economy across Europe. Portugal's Action Plan ...for Circular Economy foresees the development of regional agendas, which include the characterization of regional economic metabolism. Taking resources inputs, extractions and imports into account, as well as the generated outputs, such as exports and emissions to the environment are a fundamental need for an efficient resources management. Indicators associated with regional economic metabolism allow the identification of inefficient use of natural resources and energy, and opportunities for circularity, which can promote new business models and investments. In this context and to fulfill the current need of evaluating the regional economic metabolism, this work describes the development of the REMET-UA (REgional METabolism) model. This model was developed to take into account the specificities of Portuguese regions, allowing an analysis with a high-resolution level.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The current linear economic system has led Europe to unsustainable development, aggravating several issues, such as climate change, limitation of resources, and pollution. As a sustainable ...alternative, circular economy (CE) has been promoted around the world. This economic system allows for the maximization of a product’s life, thus decreasing its environmental impact and increasing its value. The main goal of this work is to scrutinise the concepts of CE over time, from the beginning of the concept, to its implementation in Europe and its application in Portugal. In addition, the requirement for strategies that led to studies on regional urban metabolism are addressed. Another goal is to examine Portugal and see how the country is dealing with the implementation of strategies for CE, moving from concept to practice. This part of the work resulted in the creation of the REMET-UA model, a tool to assess the regional economic metabolism, which also has the potential to evaluate synergies of materials in terms of fluxes between regions, maximizing the amount of information available at this scale for municipalities and enterprises to be used, having taken into account the purpose of circular economy. The results showed that REMET-UA is fully operational and corresponds to the goal for which the model was made. Future developments have been identified and are underway to improve the model and bring it as close to reality as possible.
The impacts of autonomous vehicles (AV) on safety, energy and atmospheric emissions have been recognised to be important issues, but an air quality impact assessment is missing. In this study, by ...using a numerical modelling approach, the impact of AV on the air quality of a medium-sized Portuguese urban area was evaluated. For that, the air pollutants nitrogen oxides (NOx) and carbon dioxide (CO2) were considered and three scenarios were developed: i) a baseline scenario; ii) an autonomous scenario, assuming an AV market penetration rate of 30%; and iii) an electric autonomous scenario, taking into account that those 30% of AV are pure battery electric cars. A modelling system composed by a road traffic model, a road transport emission model and a Computational Fluid Dynamics air quality model was used. The autonomous scenario promoted an increase of both NOx (+1.8%) and CO2 (+0.7%) emissions, while the electric autonomous scenario resulted in emission reductions of about 30% for both air pollutants. In terms of air quality, distinct patterns were found: i) the autonomous scenario promoted both increases and decreases of NOx concentrations; and ii) the electric autonomous scenario promoted a widespread reduction of NOx concentrations (with an average value of −4%). Overall the results showed that AV have the potential to improve urban air quality, but, further research is needed to enrich the findings of this work.
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•Autonomous vehicles technology is seen as an opportunity to deal with cities air pollution.•Two autonomous vehicles scenarios were studied using the VISSIM-VSP-VADIS modelling setup.•The autonomous scenario promoted both increases and decreases of NOx concentrations.•The hybrid scenario promoted a widespread reduction of NOx concentrations.•Positive and negative effects were observed, showing the need of knowledge-based planning of traffic management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Due to the likely market penetration of autonomous vehicles (AVs) in the short-medium term, several studies have analysed their environmental impact due to changes in demand patterns or market ...models. However, there is little research on the operational impact of AVs on air quality. This work aims to explore several scenarios of Avs penetration with different driving patterns and anticipate the potential impacts of traffic performance, emissions, and air quality. An urban intersection was used as a case study, namely a roundabout located in a critical context from the air pollution exposure point of view. Results show that the introduction of Avs may lead to higher travel times at peak hours and increased emissions, mainly due to AVs with defensive behaviour. Regarding air quality, the introduction of AVs led to a degradation of air quality, especially during peak hours.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Nature based solutions were used to reduce urban heating and mitigate urban sprawl.•The effects were measured in the urban heat fluxes.•WRF-SUEWS and SULD constitute a useful tool for policy ...decision.•Urban compacting reduces the effect of nature based solutions on urban heat.
Many cities are growing and becoming more densely populated, resulting in land use changes, which promotes an increase in urban heating. Nature-based solutions (NBS) are considered sustainable, cost-effective and multi-purpose solutions for these problems. While various studies assess the effects of NBS on urban heat or urban sprawl/compaction, no studies assess their cumulative effect. The main objective of this study is to assess the short-term and medium- to long-term impacts of NBS on urban heat fluxes, taking as a case study the city of Eindhoven in The Netherlands. An integrated modelling approach, composed of a coupled meteorological and urban energy balance model (WRF-SUEWS) and an hedonic pricing simulation model (SULD), is used to assess urban heat fluxes and urban compaction effects, respectively. Results show that, in the short-term, NBS have a local cooling effect due to an increase in green/blue spaces and, in the medium to long-term, an urban compaction effect due to attraction of residents from peripheral areas to areas surrounding attractive NBS. This study provides evidence that NBS can be used to reduce the effects of urban heating and urban sprawl and that an integrated modelling approach allows to better understand its overalleffects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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