317 research outputs found
Identifying critical links in urban transportation networks based on spatio-temporal dependency learning
No full textThe urban transportation network is crucial for societal development, but it is prone to failures like congestion caused by accidents or disasters. In particular, often network-wide failure is the result of a series of cascading failures originating from a small set of individual links. To prevent such failures, it is essential to identify these critical links and take early action. However, most existing approaches in the literature for evaluating the importance of each link rely on manually designed metrics (e.g., the Network Robustness Index). These methods are time-consuming and not suitable for large-scale urban networks. Additionally, these metrics fail to accurately capture the dynamic traffic interactions influenced by vehicle movement. In this paper, we present a novel method for identifying critical links by learning effective traffic interaction representation (the spatio-temporal dependencies) among roads. By representing the network as an un-directed graph and abstracting the road links as the nodes, we introduce a temporal graph attention model to capture spatial and temporal dependence between nodes. This model combines a graph attention network and a long short-term memory neural network and produces an attention matrix, which represents traffic interactions among links. Furthermore, we propose a traffic influence propagation model to evaluate the influence of each link for the entire road network based on the traffic interaction representation. We rank the importance of links based on their influence and then identify the critical links. A real-world case study in the city of Hangzhou, China is conducted to test our method and we use the network efficiency ratio to quantify its performance. The results suggest that our method can effectively identify the critical links at different periods
Novel N-Acylated Benzimidazolone Derivatives: Synthesis, 2D-QSAR and Targets Prediction
No full textA series of novel N-acylated benzimidazolone derivatives, were synthesized from 4-aminobenzoic acid, and their antifungal activities against Botrytis cinerea were evaluated by spore germination assay. Preliminary results indicated that most of the benzimidazolone derivatives had inhibitory effect on spore germination, among which 6-carboxylate substituted derivatives were more effective than its 5-substituted regioisomers. Furthermore, 2D-quantitative structure-activity relationship (2D-QSAR) studies revealed good predictive and statistically significant QSAR models, as well as highlighted that the activities were strongly influenced by the type of introduced acyl groups in the benzimidazolone moiety. Potential targets of the title compounds were predicted using ligand profiling and validated by molecular docking, and the results implied that the title compounds might be a new type of fatty acid synthetase inhibitor
Optimizing Dual Fluorescent Analysis to Investigate the Toxicity of AgNPs in <i>E. coli</i>
No full textMicrowave heating mechanism and self-healing performance of asphalt mixture with basalt and limestone aggregates
No full textTraditional asphalt mixtures can't absorb microwave energy efficiently, which limits the development of microwave heating technology in the field of road maintenance. Based on the microwave heating characteristics of basalt aggregates, the overall microwave self-healing rate of the asphalt mixture can be enhanced. The basalt was tested by XRF, XPS, XRD and electromagnetic parameters to reveal its microwave heating mechanism. Through the heating rate test, SCB test and fatigue test of asphalt mixture, its heating characteristics, flexural strength, fatigue resistance and self-healing performance were studied. The results showed that the excellent wave-absorbing properties of basalt are highly correlated with the elements of Si, Fe and Al. Its TanδM was slightly larger than TanδE, which indicated that basalt can absorb microwave energy through dielectric loss and magnetic loss. The aggregate type and particle size both affected the microwave heating rate of the aggregates. After microwave heating, the flexural strength and fatigue resistance of asphalt mixture with basalt and limestone aggregates can recover at least 65% and 23% respectively.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.Pavement Engineerin
Microwave heating mechanism and Self-healing performance of scrap tire pyrolysis carbon black modified bitumen
No full textConventional asphalt mixture has poor microwave absorbing performance and microwave heating efficiency. Based on the characteristics of dielectric loss of scrap tire pyrolysis carbon black (PCB), it is proposed to improve the microwave absorbing performance and self-healing rate of bitumen. The phase composition and electromagnetic parameters of PCB were tested to reveal its microwave heating mechanism. The preparation parameters, heating characteristics and self-healing properties of PCB modified bitumen were studied through the dispersion uniformity test, microwave heating test and SCB test. The main phases of PCB are microwave absorbing carbon and silicon, indicating that PCB is a good electric loss microwave absorbing material. 40 min is the recommended mixing time of 15% PCB modified bitumen. PCB's dosage, microwave frequency and microwave heating time have significant effects on the microwave heating characteristics of PCB modified bitumen. PCB can improve high-temperature stability, thermal conductance, heat storage capacity and self-healing rate of bitumen.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.Pavement Engineerin
Investigation of the moisture damage and the erosion depth on asphalt
No full textMoisture erosion is one of the key factors leading to asphalt pavement damage, and the erosion depth indicates the moisture damage level but it is usually neglected. In order to study the moisture erosion and the erosion depth, this study characterized the chemical structure, rheological property and adhesion property of asphalt at different depths after immersion for different periods. To further explore the diffusion mechanism of eroded asphalt, a Log-log numerical model was established based on the Fick's second law to calculate the diffusion coefficient throughout the depth. The results indicate that it takes just four hours for water to penetrate a 25 μm asphalt film. The relation between erosion depth and immersion period presents three stages, and the process can be fitted with a polynomial model. At the macroscopic level, there is a lag between the changes in adhesion property with chemical structure and rheological property. Additionally, the periodicity of moisture erosion process was verified by the calculation of diffusion factor. In summary, the diffusion mechanism of eroded asphalt by moisture can provide a theoretical basis for the development of laboratory moisture erosion test specification, thus avoiding the waste of raw materials.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.Materials and Environmen
In situ drug-receptor binding kinetics in single cells: a quantitative label-free study of anti-tumor drug resistance
Get PDFabstract: Many drugs are effective in the early stage of treatment, but patients develop drug resistance after a certain period of treatment, causing failure of the therapy. An important example is Herceptin, a popular monoclonal antibody drug for breast cancer by specifically targeting human epidermal growth factor receptor 2 (Her2). Here we demonstrate a quantitative binding kinetics analysis of drug-target interactions to investigate the molecular scale origin of drug resistance. Using a surface plasmon resonance imaging, we measured the in situ Herceptin-Her2 binding kinetics in single intact cancer cells for the first time, and observed significantly weakened Herceptin-Her2 interactions in Herceptin-resistant cells, compared to those in Herceptin-sensitive cells. We further showed that the steric hindrance of Mucin-4, a membrane protein, was responsible for the altered drug-receptor binding. This effect of a third molecule on drug-receptor interactions cannot be studied using traditional purified protein methods, demonstrating the importance of the present intact cell-based binding kinetics analysis.The final version of this article, as published in Scientific Reports, can be viewed online at: http://www.nature.com/articles/srep0660
Effects of GBFS content and curing methods on the working performance and microstructure of ternary geopolymers based on high-content steel slag
No full textAimed to address the low utilization rate of steel slag (SS) and its challenge in resource utilization in China, this study developed ternary geopolymers made by high-content (50%) SS together with fly ash (FA) and granulated blast furnace slag (GBFS). The effects of GBFS content (0–40%) and curing methods (water curing, standard curing, sealed curing, and heat curing) on the working performance and microstructure of geopolymers were investigated. Microscopic analysis such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM) were utilized to investigate the hydration process and products of geopolymers under different curing conditions and GBFS content. The results indicated that when the GBFS content increased from 0% to 40%, the fluidity of the mixture decreased by 11.7%, the initial setting time of the geopolymer slurry decreased by 76%, and the geopolymer mortar's 28d compressive strength increased from 31.9 MPa to 60.6 MPa. At room temperature, the geopolymer mortar's 28d compressive strength was higher under standard curing (70.8 MPa) compared to water curing (57.5 MPa) and sealed curing (68 MPa). The geopolymer mortar cured at 60 °C for 24 h exhibited the highest 28d compressive strength (76.3 MPa). However, excessively high curing temperatures or prolonged durations led to more shrinkage cracks and reduced the compressive strength. The microscopic analysis revealed that the main gel products of ternary geopolymer were C-(A)-S-H gel. The amount of gel products is directly related to the strength of geopolymers. The developed ternary geopolymer has the potential to promote the large-scale utilization of SS in the concrete industry, making a significant contribution to sustainable development.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.Materials and Environmen
Plasmonic-based Imaging Detection of Chemical Reactions
Get PDFabstract: An imaging measurement technique is developed using surface plasmon resonance. Plasmonic-based electrochemical current imaging (P-ECi) method has been developed to image the local electrochemical current optically, it allows us to measure the current density quickly and non-invasively [1, 2]. In this thesis, we solve the problems when we extand the P-ECi technique to the field of thin film system. The P-ECi signal in thin film structure was found to be directly proportional to the electrochemical current. The upper-limit of thin film thickness to use the proportional relationship between P-ECi signal and EC current was discussed by experiment and simulation. Furthermore, a new algorithm which can calculate the current density from P-ECi signal without any thickness limitation is developed and tested. Besides, surface plasmon resonance is useful phenomenon which can be used to detect the changes in the refractive index near the gold sensing surface. With the assistance of pH indicator, by applied EC potential on the gold film as the working electrode, the detection of H2 evolution reaction can be enhanced. This measurement technique is useful in analyzing local EC information and H2 evolution. References [1] S. Wang, et al., "Electrochemical Surface Plasmon Resonance: Basic Formalism and Experimental Validation," Analytical Chemistry, vol. 82, pp. 935-941, 2010/02/01 2010. [2] X. Shan, et al., "Imaging Local Electrochemical Current via Surface Plasmon Resonance," Science, vol. 327, pp. 1363-1366, March 12, 2010 2010.Dissertation/ThesisM.S. Electrical Engineering 201
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