39 research outputs found
The Satellite Communications Network of Excellence 'SatNEx': Removing Bariers, Integrating Research, Spreading Excellence
No full textSatNEx aims to rectify the fragmentation in satellite communications research by bringing together Europe’s leading academic institutions and research organisations in a cohesive and durable way. The resultant pan-European network provides a collective grouping of expertise and state-of-the-art laboratory facilities that would otherwise remain dispersed throughout Europe
Optimize the measurement of Poly-hydroxy-alkanoates (PHA) in biomass
No full textPoly-hydroxy-alkanoate (PHA) is an intracellular polymer that can be used as an energy and carbon source by microorganisms. Measuring PHA is important for understanding the microbial metabolism of enhanced biological phosphorus removal (EBPR) and aerobic granular sludge (AGS) systems. There is a commonly used method to measure PHA, which is based on organic solvent extraction and gas chromatography (GC). However, there are different versions of the same method with different parameters, but the role of some of these parameters is unclear. When different types of biomass are analyzed, there is a requirement to understand the parameters and obtain an optimal protocol. In this study, the effect of various digestion times, different alcohols and organic solvents, and acid concentrations were tested to obtain the optimal protocol. The results showed that a minimum digestion time was required to get the maximum yield of PHA, and the time might differ when using different types of biomass. Methanol was shown to be better for GC separation than propanol. Using different organic solvents didn’t affect the final concentration, and an optimal acid concentration was required to determine by comparison. The GC temperature program optimization showed that lower oven temperature in GC is more beneficial for peak separation. From the analysis, it would be suggested to use methanol and chloroform for digestion and keep the digestion time for 24 hours.CIE5050-09Civil Engineering | Environmental Engineerin
Glucose conversion by aerobic granular sludge
No full textAerobic granular sludge (AGS) is an innovative biotechnology extensively applied for treating municipal wastewater, and it can potentially treat sugar industry wastewater. Glucose is a prevalent substrate in sugar industry wastewater; nevertheless, the effect of glucose on AGS systems remains unexplored. In this study, an AGS reactor using glucose as the sole carbon source was operated in anaerobic-aerobic cycles. The system maintained a solids retention time (SRT) of 10 days, resulting in good granulation and enhanced biological phosphorus removal (EBPR) performance. The glucose fed was rapidly taken up within 10 minutes, with a portion stored as intracellular polymers such as glycogen and poly-hydroxy-alkanoates (PHAs), while another portion underwent anaerobic fermentation to lactate and formate. The carbon balance was not completely closed, with 16% of the carbon speculated to be utilized for the production of an unidentified polymer. The microbial community consisted of diverse organisms, with Micropruina identified as the most abundant genera and Ca. Accumulibacter (a typical type of PAOs) as the second most abundant genera based on metagenomic analysis. A batch test was conducted by adding an excess of glucose, lactate, and formate, revealing that lactate was the probable substrate utilized by PAOs. Additionally, Micropruina was hypothesized to be involved in glucose consumption, glycogen storage, and lactate production. Micropruina and Ca. Accumulibacter collaborate in utilizing glucose, providing them with a significant competitive advantage within the system. Due to their slow growth rate, these bacteria play a crucial role in achieving favorable granulation when supplied with glucose. Promoting the growth of these organisms can be a valuable strategy in engineering applications.Civil Engineering | Environmental Engineerin
The impact of COVID-19 pandemic on public transport usage and route choice: Evidences from a long-term tracking study in urban area
No full textThe COVID-19 pandemic strongly affected mobility around the world. Public transport was particularly hindered, since people may perceive it as unsafe and decide to avoid it. Moreover, in Switzerland, several restrictions were applied at the beginning of the first pandemic wave (16/03/2020), to reduce the contagion. This study observes how the pandemic affected travel behaviour of public transport users, focusing on route choice and recurrent trips. We conducted a travel survey based on GPS tracking during the first pandemic wave, following 48 users for more than 4 months. The very same users were also tracked in spring 2019, allowing a precise comparison of travel behaviour before and during the pandemic. We analyse how the pandemic affected users, in terms of travel distance, mode share and location during the day. We specifically focus on recurrent trips, commuting and non-commuting, observing how mode and route changed between the two different periods. Finally, we estimate a route choice model for public transport (Mixed Path Size Logit), based on trips during the two different years, to identify how the route choice criteria changed during the pandemic. The main differences identified in travel behaviour during the pandemic are a different perception of costs of transfers and of travel time in train, and that users no longer have a clear preferred route for a recurrent trip, but often choose different routes
Performance evaluation of the interworking between DVB-RCS and WiMAX
No full textAiming to provide low-cost universal broadband access, this paper describes the strategy that supports the integration of hybrid satellite and WiMAX, based on the network architecture proposed in the IST Satsix project. In this context, WiMAX networks can be used as wireless local loops integrated with a satellite network, lowering the cost of the broadband internet connections and providing a universal access to rural and marine areas. The paper presents the problems concerning the interworking between DVB-RCS and WiMAX technologies and the solutions adopted in the SatSix research project, partially funded by European Commission within the Information Society Technologies (IST) 6th Framework Programme. © 2007 by SatSix consortium
New architecture for next generation broadband satellite systems: the SATSIX approach
No full textThe EU-funded IST FP6 Project Satellite-based communications systems within IPv6 (SATSIX) is implementing and validating innovative concepts and cost-effective solutions for broadband satellite systems that build upon the DVB-RCS/S2 standards and services. It promotes the introduction of IPv6 into satellite- based communications systems and the development of hybrid networks that combine the use of satellite with wireless access technologies. The main objective is to lower the cost of broadband satellite access, through the development of new satellite access techniques and the integration of wireless local loops (WiFi and WiMax). Simulations, test beds and trial networks will show how satellite broadband access can be integrated into Next Generation Networks, based on IPv6, to support new multimedia applications
The impact of COVID-19 pandemic on public transport usage and route choice: Evidences from a long-term tracking study in urban area
No full textISSN:0967-070
Antifragile Perimeter Control: Anticipating and Gaining from Disruptions with Reinforcement Learning
Full text linkThe optimal operation of transportation networks is often susceptible to
unexpected disruptions, such as traffic incidents and social events. Many
established control strategies rely on mathematical models that struggle to
cope with real-world uncertainties, leading to a significant decline in
effectiveness when faced with substantial disruptions. While previous research
works have dedicated efforts to improving the robustness or resilience of
transportation systems against disruptions, this paper applies the cutting-edge
concept of antifragility to better design a traffic control strategy for urban
road networks. Antifragility sets itself apart from robustness and resilience
as it represents a system's ability to not only withstand stressors, shocks,
and volatility but also thrive and enhance performance in the presence of such
adversarial events. Hence, modern transportation systems call for solutions
that are antifragile. In this work, we propose a model-free deep Reinforcement
Learning (RL) scheme to control a two-region urban traffic perimeter network.
The system exploits the learning capability of RL under disruptions to achieve
antifragility. By monitoring the change rate and curvature of the traffic state
with the RL framework, the proposed algorithm anticipates imminent disruptions.
An additional term is also integrated into the RL algorithm as redundancy to
improve the performance under disruption scenarios. When compared to a
state-of-the-art model predictive control approach and a state-of-the-art RL
algorithm, our proposed method demonstrates two antifragility-related
properties: (a) gradual performance improvement under disruptions of constant
magnitude; and (b) increasingly superior performance under growing disruptions.Comment: 32 pages, 13 figure
In-situ formed amorphous phase in aluminum/steel friction stir welds: Interface evolution and strength improvement
No full textAluminum/steel structures are widely proposed for weight reduction in aviation, aerospace, and automotive industries, whereas the applications of aluminum/steel structures are still limited due to the unreliable welding related to the intermetallic compounds. In this study, an amorphous layer was in-situ formed at the aluminum/steel interface, replacing the intermetallic compounds, and strengthening the welds. The effects of the plunge depth on the microstructure and mechanical properties of the Al/steel friction stir welds were further investigated. The amorphous phase was only formed when the welding tool was plunged to the interface precisely. Once the plunge depth was further increased, the amorphous layer would grow over the critical thickness of 18 nm and, subsequently, be replaced by the FeAl3 and FeAl. Different interfacial microstructure led to the different strength and fracture characteristics. The ultimate load of 6237 N was achieved with the in-situ formed amorphous layer, and it was improved by 45 %, as compared to the previous results
