132571 research outputs found
Sort by
Enhancing the DNA yield intended for microbial sequencing from a low-biomass chlorinated drinking water
No full textDNA extraction yield from drinking water distribution systems and premise plumbing is a key metric for any downstream analysis such as 16S amplicon or metagenomics sequencing. This research aimed to optimize DNA yield from low-biomass (chlorinated) reverse osmosis-produced tap water by evaluating the impact of different factors during the DNA extraction procedure. The factors examined are (1) the impact of membrane materials and their pore sizes; (2) the impact of different cell densities; and (3) an alternative method for enhancing DNA yield via incubation (no nutrient spiking). DNA from a one-liter sampling volume of RO tap water with varying bacterial cell densities was extracted with five different filter membranes (mixed ester cellulose 0.2 μm, polycarbonate 0.2 μm, polyethersulfone 0.2 and 0.1 μm, polyvinylidene fluoride 0.1 μm) for biomass filtration. Our results show that (i) smaller membrane pore size solely did not increase the DNA yield of low-biomass RO tap water; (ii) the DNA yield was proportional to the cell density and substantially dependent on the filter membrane properties (i.e., the membrane materials and their pore sizes); (iii) by using our optimized DNA extraction protocol, we found that polycarbonate filter membrane with 0.2 μm pore size markedly outperformed in terms of quantity (DNA yield) and quality (background level of 16S gene copy number) of recovered microbial DNA; and finally, (iv) for one-liter sampling volume, incubation strategy enhanced the DNA yield and enabled accurate identification of the core members (i.e., Porphyrobacter and Blastomonas as the most abundant indicator taxa) of the bacterial community in low-biomass RO tap water. Importantly, incorporating multiple controls is crucial to distinguish between contaminant/artefactual and true taxa in amplicon sequencing studies of low-biomass RO tap water.BT/Environmental Biotechnolog
Fishermen landscape-From water to land: Develop resilient principles to rebuild gradient-landscape in PRD
No full textThe Pearl River Delta (PRD) has always been one of the centers of gravity for China's economic development. Over the past few decades, the PRD has been undergoing urban development at an astonishing rate, but this development momentum has begun to wane in recent years. The development dividend initially gained from the manufacturing industry is gradually diminishing, and the whole region is facing a transformation. To meet the needs of the manufacturing industry, many rural villages have rented out their land to factories, and the living space for farmers and fishermen has been continuously reduced. Pollution brought about by the establishment of factories has also seriously affected the water system of the Pearl River, bringing about the extinction of aquatic organisms.Not all groups of people have enjoyed the dividends of economic development in the Pearl River Delta. Especially the fishermen among the marginalized people, their living space and production sources are threatened by urban expansion. However, fishermen, as the first to settle in the Pearl River Delta and have lived on the land for thousands of years, have their unique wisdom about the land and the water system. Therefore, the project hopes to help the region achieve sustainable development from the perspective of the fishermen while ensuring their livelihoods.The project has developed a core fishermen's habitat framework through theoretical research. Firstly, based on this framework, the project collected data and information on typical fishing villages classified the fishing villages in the Pearl River Delta (PRD), and summarized their specific elements. Secondly, the project selected one of the fishing villages for design exploration, exploring specific habitat modifications and area-specific planning strategies. Finally, the design logic implemented in the design exploration was utilized to examine the principles of the other two types of fishing villages, and a relatively feasible way of application was proposed.Landscape has always embodied the mutual compromise between man and nature. In the past, humans have forced nature to make compromises, leading to the increasingly severe ecological degradation problems today. It is time to think differently about the relationship between man and nature, so the project hopes to help the residents of the Pearl River Delta, and nature reach a new coexistence through the means of landscape modification, which will no longer be a relationship of forcing one party to compromise, but rather a relationship of balanced development.Architecture, Urbanism and Building Sciences | Landscape Architectur
Scaling up dynamic charging infrastructure: Significant battery cost savings
No full textLarge-scale electrification of heavy-duty road freight faces challenges including scarcity of charging infrastructure and high battery costs. Dynamic charging could help overcome these challenges by enabling trucks to charge while driving. Important additional benefits for carriers related to lower required sizes and longer lifetimes of batteries could justify the required investments. The study investigates the optimal configuration of network sections to be electrified so that the balance between costs and benefits turns out positive. A case study for a highway network spanning 4 countries in Europe suggests that dynamic charging can lead to a significant reduction in overall transport system costs, up to very large network sizes. The study supports the decision-making of policymakers and road authorities by providing new insights into the costs and benefits of dynamic charging networks, and simultaneously considering the perspectives of investors and users.Transport and PlanningIntegral Design & ManagementTransport and Logistic
Physics-informed machine learning for nowcasting extreme rainfall
No full textThe thesis explores an innovative technique for enhancing the precision of short-term weather forecasts, particularly in predicting extreme weather phenomena, which present a notable challenge for existing models such as PySTEPS due to their volatile behavior. Leveraging precipitation and meteorological data sourced from the Royal Netherlands Meteorological Institute (KNMI), the research innovates through the development of a physics-informed neural network. Central to this approach is the implementation of a Physics-Informed Discriminator GAN (PID-GAN), a method that embeds physical principles directly into the adversarial training regime. The architecture is marked by the integration of a Vector Quantization Generative Adversarial Network (VQ-GAN) and a Transformer as the generator, complemented by a temporal discriminator as the discriminator component. Results from this study indicate a notable advancement over traditional numerical weather prediction and cutting-edge deep learning models, underscoring the PID-GAN model's superiority in delivering accurate precipitation nowcasting metrics.Electrical Engineering | Circuits and System
Empirical assessment of ChatGPT’s answering capabilities in natural science and engineering
No full textChatGPT is a powerful language model from OpenAI that is arguably able to comprehend and generate text. ChatGPT is expected to greatly impact society, research, and education. An essential step to understand ChatGPT’s expected impact is to study its domain-specific answering capabilities. Here, we perform a systematic empirical assessment of its abilities to answer questions across the natural science and engineering domains. We collected 594 questions on natural science and engineering topics from 198 faculty members across five faculties at Delft University of Technology. After collecting the answers from ChatGPT, the participants assessed the quality of the answers using a systematic scheme. Our results show that the answers from ChatGPT are, on average, perceived as “mostly correct”. Two major trends are that the rating of the ChatGPT answers significantly decreases (i) as the educational level of the question increases and (ii) as we evaluate skills beyond scientific knowledge, e.g., critical attitude.ChemE/Process Systems EngineeringPattern Recognition and BioinformaticsEthics & Philosophy of Technolog
Dutch Housing Commons: Non-speculative housing within and against the housing market
No full textThe Netherlands is facing a housing shortage and adequate housing provision is lacking. Citizens are eager to act on their own through bottom-up initiatives. However, bottom-up initiatives (such as cooperative housing) do not thrive within the current housing market and therefore significant development of cooperative housing in the Netherlands stays off. This research aims to support the development of cooperative housing in the Netherlands. This is being achieved through constructing an alternative reality of the housing market through composing a play script. The script is being informed by interviews, literature review and analysing case study projects. The interviews were conducted among the present stakeholders (the academic, the advocate, the architect, the bank, the cooperative, the developer, the dweller, the municipality). All together, the research hopes to transfer these thoughts and findings on cooperative housing to continue this collective process.Architecture, Urbanism and Building Sciences | Explorela
Feasibility study of Energetics in Nature-inspired Foraging for Lunar Resource Exploitation
No full textThe rediscovered interest in space exploration has led to plans to establish outposts on the Moon and beyond. The lunar bases currently planned are to be manned incrementally, with robots performing most work. With new trends in robotics, the use of collaborating swarms has become more abundant. To support lunar operation, a distinct area within swarming, namely foraging, is proposed. Foraging systems have the primary objective of recovering resources. From literature, no foraging framework was found that included system maintenance in its mechanisms. This report aims to answer the question if this is possible while maintaining the benefits of foraging.The research considers the fundamental act of recharging as its required maintenance task. To evaluate it dynamically, a rudimentary energetics model is included. For the framework of foraging, the work of [Adams] is used as a baseline. The newly proposed system implements an additional recharging region and role to perform recharging activities, both having major implications for role selection and agent operation. Furthermore, to enable navigation based on energy considerations, the experience communicated by mobile agents is amended to include the energy cost of a travelled path. In doing so, additional quality indicators of paths are available making path optimization a more dynamic process resulting in finer population behaviour. Finally, the decaying of beacons is updated and a fallback feature is introduced to maximize agent utilization.The newly developed foraging system is evaluated using data collected through simulation in Webots. Simulation scenarios included obstacles with impenetrable boundaries and surfaces with increased rolling friction to emulate cost-expensive regions. Qualitative analysis identified all features of the foraging system as expected, both in the exploration and exploitation phase. Quantitative results proved that the system is able to function with the added requirements of recharging, perform path optimization with the additional path quality indicator, and can do so in various types of scenarios. With this, the research statement that foraging functionality is achievable with the practical considerations of robotics is confirmed to hold.Double degree in Aerospace Engineering and Mechanical Engineering | Systems and ControlAerospace EngineeringMechanical Engineering | Systems and Contro
Reshaping the booking process of international train tickets in Europe: An iterative design process towards intuitive ticketing
No full textInternational train travel could serve as a more sustainable alternative to flying, especially for short distance journeys up to 750 km. Though both forms of transport have negative impacts, the environmental costs of travelling by train are significantly lower than travelling by plane (European Environmental Agency, 2021). Therefore, the European Union, governments, environmentalists and railway companies see great value in promoting train travel over flying for short distance journeys (Ministry of IenW, 2022).In order to further promote this transition, a couple of action points have been identified by Donners (2018) to improve international train travel, ticketing being one of them. Unlike booking a flight ticket - which can be done within just a few clicks - finding, comparing, and booking a train ticket has proven to be a more challenging task. Recent research conducted by the University of St. Pölten in Austria (Preslmayr, 2022) revealed that one third of travellers are unable to complete their booking, highlighting the difficulty of this process. In order to promote the transition from air to rail for short distance journeys, the bookability of international train tickets in Europe needs to be improved.It is difficult to change a complex system such as the international railway industry, but we can help travellers navigate it. This project aims to do that by redesigning a booking platform and app that support holiday travellers when booking and potentially rescheduling their international train journey in Europe with an intuitive booking process that provides clarity and guidance at every step leaving them feeling confident and excited about their journey.An iterative design process led to the final design proposal. Created to be intuitive, supportive, adaptive and exciting, this redesign booking platform aims to ensure that every traveller, regardless of their prior travel experience, can easily book a suitable train ticket, leaving them feeling confident and excited about their journey ahead. The booking platform was designed to align with the user needs and decision making patterns. Core features to support this include route characteristics, transfer alternatives and search filters. A travel app was redesigned to complement the booking platform, creating a bridge between the booking process and the train journey. In case disruption does occur, the travellers are supported by the travel app that provides clear guidance for how they can continue their journey.The user evaluation of the final design proposal shows promising results with an excellent score on its usability according to the adjective rating scale of Bangor et al. (2009) and positive responses from participants. To facilitate this redesigned user journey, some supportive processes need to be improved, including open communication and collaboration between carrier and ticket distributors, updated route information database and an EU wide disruption protocol. All in all, it is difficult to change a large complex system such as the international train industry, but we can help travellers navigate it. While the railway system is expected to evolve, impactful changes may take time. Meanwhile, optimising services through redesigns can have a significant immediate effect on the travellers experience and provide access to a sizable potential customer segment. Therefore, further exploring and implementing the designs as proposed in this report will improve the bookability of international train tickets in Europe.Design for Interactio
Model Reference Adaptive Stabilizing Control with Application to Leaderless Consensus
No full textThis article describes an extension of the well-known model reference adaptive control (MRAC) approach. The extension relies on explicitly involving the tracking error in the feedback control law: it is shown that including this term along with its appropriate extra adaptive gain allows one to handle possibly unstable reference dynamics. Owing to its stabilizing nature, the proposed framework is referred to as model reference adaptive stabilizing control. Such an extension turns out to be particularly useful in leaderless consensus of heterogeneous uncertain agents, since the literature has discussed that leaderless adaptation may not avoid unstable closed-loop dynamics. In such consensus setting, the framework, referred to as model reference adaptive stabilizing consensus, generalizes the existing MRAC-based consensus schemes and can achieve consensus when state-of-the-art MRAC-based schemes may fail.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Delft Center for Systems and Contro
Hexagonal Boron Nitride Spacers for Fluorescence Imaging of Biomolecules
No full textFluorescence imaging is an invaluable tool to investigate biomolecular dynamics, mechanics, and interactions in aqueous environments. Two-dimensional materials offer large-area, atomically smooth surfaces for wide-field biomolecule imaging. Despite the success of graphene for on-chip biosensing and biomolecule manipulation, its strong fluorescence-quenching properties pose a challenge for biomolecular investigations that are based on direct optical readouts. Here, we employ few-layer hexagonal boron nitride (hBN) as a precisely tailorable fluorescence spacer between labelled lipid membranes and graphene substrates. By stacking high-quality hBN crystals in the 10–20 nm thickness range on monolayer graphene, we observe distance-dependent fluorescence intensity variations. Remarkably, with hBN spacers as thin as 20 nm, the fluorescence intensity is comparable to bare SiO2/Si substrates, while the intensity was reduced to 60 % and 80 % with ~10 nm and ~16 nm hBN thicknesses respectively. We confirm that pre-determined hBN thicknesses can be employed to control the non-radiative energy transfer properties of graphene, with fluorescence quenching following a d−4 distance-dependent behaviour. This seamless integration of electronically active and dielectric van der Waals materials into vertical heterostructures enables multifunctional platforms addressing the manipulation, localization, and visualization of biomolecules for fundamental biophysics and biosensing applications.D.H.S. and S.C. acknowledge funding from the European Union's Horizon 2020 research and innovation program (ERC StG, SIMPHONICS, Project No. 101041486). S.C. acknowledges a Delft Technology Fellowship. X.Y. acknowledges funding from the Chinese Scholarship Council (Scholarship No. 202108270002). Z.Y. acknowledges funding from NWO (Project MechanoPore).Dynamics of Micro and Nano System