Transport Network Research Articles

Study on physical properties and snow-melting performance of multilayer composite conductive-pervious concrete for improving the snow-melting efficiency and energy consumption of ECON

One of the most significant challenges facing transport networks in cold regions is snow accumulation on road surfaces. This can lead to traffic congestion and safety issues. While electrically conductive concrete (ECON) heated pavement systems (HPS) offer several advantages, including stability, and low environmental impact, they also present certain limitations, such as low snow-melting efficiency and high snow-melting energy consumption. In this study, a SiO2 aerogel mortar thermal-insulation layer and a self-compacting concrete structural layer were set underneath the reduced graphene oxide (RGO) composite conductive concrete, and the straight pervious channels were prefabricated, to reduce the snow-melting efficiency and energy consumption through the preparation of multilayer composite conductive-pervious concrete integrated specimen. The initial objective was to investigate the influence of SiO2 aerogel substitution rate on the mechanical properties and thermal conductivity of thermal-insulation mortar. Secondly, the impact of the thickness of the conductive layer and thermal-insulation layer on the mechanical properties of the integrated specimen was analyzed. Finally, the impact of SiO2 aerogel thermal-insulation mortar and straight pervious channels on the integrated specimen's snow-melting performance was evaluated through a snow-melting test, which assessed the efficiency and energy consumption of the snow-melting process. The results indicate that when the SiO2 aerogel substitution rate was 40 %, the thermal-insulation mortar exhibited favorable mechanical and thermal-insulation properties. The 5 cm conductive layer and the 1 cm thermal-insulation layer achieved good mechanical properties of the integrated specimen. In comparison to single-layer composite conductive concrete, the snow-melting time and energy consumption of multilayer composite conductive-pervious concrete integrated specimen were reduced by 23.05 % and 21.30 %, respectively. The straight pervious channels permit the immediate discharge of water produced by snow melting, thereby reducing the heat transfer from the snow-melting board to the water film. The setting of SiO2 aerogel thermal-insulation mortar enables the retention of heat for the heating of the snow-melting board and snow melting, which improves the snow-melting performance.

Fire-resistant and thermal-insulating alginate aerogel with intelligent bionic armor for exceptional mechanical and fire early-warning performance

Intelligent bio-based aerogels have attracted increasing attention in several key areas due to their unique porous structure and sustainability, but they suffer from poor fire safety, strength, and durability under harsh conditions. Here, we prepared sodium alginate/hydroxyapatite/graphene oxide (SA@HAP@GO) aerogel by in-situ growth and directional assembly technology, and an intelligent “bionic armor” was put on the surface of SA aerogel. It not only endows aerogel with high strength (2.3 MPa) and long-time water resistance (30 days) but also maintains the lightweight (0.039 g cm−3) and thermal insulation properties (0.03537 W m-1K−1) of original aerogel. Under fire conditions, the compact physical barrier makes aerogel obtain the excellent fire-resistant stability and fire-safety performance. Besides, the directional assembly of GO and the chelating effect of Ca2+ on aerogel surface promote the formation of a three-dimensional electron transport network during reduction process, thus achieving a fast and long-lasting fire early-warning response (1.95 s). The corresponding mechanism was demonstrated by molecular theoretical calculation and experiments. This multifunctional aerogel provides a new way for sustainable and high-performance thermal-insulation materials and shows a wide application in energy security.

Fluorinated metal-organic framework aerogels with enhanced moisture resistance and efficient gas diffusion for CO2 capture

Escalating CO2 levels in confined spaces threatens human well-being and safety, underscoring the urgent need for effective CO2 mitigation strategies. Metal-organic frameworks (MOFs), with their large surface areas and capacious pores, represent a promising avenue for CO2 capture. However, their application is often limited by susceptibility to moisture and lack of uniformity in mesopore distribution. Here, we present a novel approach involving ligand fluorination modification and pore reconstruction to fabricate ultralight, highly moisture resistant, and hierarchically porous UiO-66-NH2-F4 aerogels. This design ingenuity promotes the formation of an efficient gas transport network and generates an abundance of micropores decorated with hydrophobic units, effectively shielding CO2 adsorption from the interference of water molecules. The UiO-66-NH2-F4 aerogels exhibit an impressive CO2 adsorption capacity of 5.18 mmol/g (dry) and 4.48 mmol/g (70 % RH) at 298 K, a remarkable CO2/N2 selectivity of 29, and exceptional cyclability. Density functional theory (DFT) calculations further elucidate the robust binding interactions of these CO2-selective UiO-66-NH2-F4 aerogels, attributing them to the tailed pore environment created by fluorinated hydrophobic groups and the accessibility of adsorption sites. This work charts a promising course for developing moisture-resistant and hierarchically porous MOF aerogels, which are poised to revolutionize CO2 adsorption practices in confined environments.

Reconstructing and assessing global maritime transport network: based on the Port Cargo Composite Transport index

ABSTRACT Solution to the problem of limited explanatory power of transport economics due to the homogenisation of existing the Global Maritime Transport Network (GMTN) construction indicators. By integrating the Port Cargo Composite Transport (PCCT) index and considering the volume-value mismatch relationship and the type and flow of cargo transported in ports, the GMTN can be reconstructed through a bottom-up logic. Combining the complex network, natural breaks, and point mutual information method with the Leiden and PageRank algorithm, the characteristics of the GMTN were derived from three aspects, i.e. network topology, node characteristics, and inter-node dependency. The GMTN presents the characteristics as follows. Community division presents typical geographical aggregation and industrial complementarity. Node characteristics show the classic phenomenon of rich people’s clubs, with obvious heavy-tailed distribution. Maritime transport linkage preferences present a phenomenon of geographical proximity, and their expansion can clarify the direction of the main links. Enhancing their maritime links will be more targeted to support the transport of trade cargoes. These findings help us to understand the characteristics of the international maritime trade pattern, and provide decision references for industry stakeholders to provide a strategic layout of maritime transport.

F-Deepwalk: A Community Detection Model for Transport Networks.

The design of transportation networks is generally performed on the basis of the division of a metropolitan region into communities. With the combination of the scale, population density, and travel characteristics of each community, the transportation routes and stations can be more precisely determined to meet the travel demand of residents within each of the communities as well as the transportation links among communities. To accurately divide urban communities, the original word vector sampling method is improved on the classic Deepwalk model, proposing a Random Walk (RW) algorithm in which the sampling is modified with the generalized travel cost and improved logit model. Urban spatial community detection is realized with the K-means algorithm, building the F-Deepwalk model. Using the basic road network as an example, the experimental results show that the Deepwalk model, which considers the generalized travel cost of residents, has a higher profile coefficient, and the performance of the model improves with the reduction of random walk length. At the same time, taking the Shijiazhuang urban rail transit network as an example, the accuracy of the model is further verified.

Experimental evaluation of various flow meters using gaseous CO2

The need for accurate flow measurement within the Carbon Capture, Utilisation and Storage (CCUS) transport network is widely reported and understood as a requirement of Emission Trading Schemes and commercial contracts. In meeting this requirement, traceable calibration is needed in conditions which closely mimic the process conditions. However, currently accredited calibration facilities cannot meet the conditions for calibrating in gaseous CO2 and so a likely alternative solution for these custody transfer flow meters is to be calibrated with an alternative fluid and the calibration transferred. In this article, which was produced under the framework of the EMPIR project “Metrology for Decarbonising the Gas Grid”, the authors will investigate this approach with a number of flow meters tested in natural gas, nitrogen gas and finally in carbon dioxide gas at varying pressures. The results of which will suggest that orifice and Coriolis meters can be calibrated in another fluid however, an ultrasonic meter would require further work and potentially require calibration in CO2. This article will also investigate the effects of impurities in a CO2 gas stream for a rotary displacement flow meter and a thermal mass flow controller compared against a piston prover which provides a primary reference flow standard.

State management of public investment in road construction in Vietnam: Current situation and solutions

This study examines Vietnam’s state management of public investment in road construction. The development of road transport infrastructure is in extremely high demand as Vietnam undergoes an economic transition. Despite the fact that the effects of the COVID-19 pandemic have caused the economy to grow more slowly recently, public investment in the transport industry has increased significantly. Several modern, large-scale road works that have been finished and put into operation are having a significant positive impact on urbanization, connecting regions, and socioeconomic development. However, public investment in road transport construction still has a lot of issues that need to be fixed. The state’s weakness is one of the primary issues that reduces investment efficiency. This study analyzes the state management of public investment in road construction, according to the following contents: legal system and policies; formulation and implementation of public investment plans; inspection and supervision by state management agencies. The method of collecting secondary data and primary data (through sociological investigation) is used and combined with Statistical Package for the Social Sciences (SPSS) software to determine the influencing factors and find out the problems and their causes. Therefore, this study proposes a number of urgent and practical solutions to improve the state management of public investment in road construction and develop a synchronized road transport network.

IP3R1 is required for meiotic progression and embryonic development by regulating mitochondrial calcium and oxidative damage

Calcium ions (Ca2+) regulate cell proliferation and differentiation and participate in various physiological activities of cells. The calcium transfer protein inositol 1,4,5-triphosphate receptor (IP3R), located between the endoplasmic reticulum (ER) and mitochondria, plays an important role in regulating Ca2+ levels. However, the mechanism by which IP3R1 affects porcine meiotic progression and embryonic development remains unclear. We established a model in porcine oocytes using siRNA-mediated knockdown of IP3R1 to investigate the effects of IP3R1 on porcine oocyte meiotic progression and embryonic development. The results indicated that a decrease in IP3R1 expression significantly enhanced the interaction between the ER and mitochondria. Additionally, the interaction between the ER and the mitochondrial Ca2+ ([Ca2+]m) transport network protein IP3R1-GRP75-VDAC1 was disrupted. The results of the Duolink II in situ proximity ligation assay (PLA) revealed a weakened pairwise interaction between IP3R1-GRP75 and VDAC1 and a significantly increased interaction between GRP75 and VDAC1 after IP3R1 interference, resulting in the accumulation of large amounts of [Ca2+]m. These changes led to mitochondrial oxidative stress, increased the levels of reactive oxygen species (ROS) and reduced ATP production, which hindered the maturation and late development of porcine oocytes and induced apoptosis. Nevertheless, after treat with [Ca2+]m chelating agent ruthenium red (RR) or ROS scavenger N-acetylcysteine (NAC), the oocytes developmental abnormalities, oxidative stress and apoptosis caused by Ca2+ overload were improved. In conclusion, our results indicated IP3R1 is required for meiotic progression and embryonic development by regulating mitochondrial calcium and oxidative damage.

Modulation of electron transfer behavior on Fe2P-Co2P/NPC oxygen electrocatalyst by lattice cation substitution engineering and charge transport network design for rechargeable Zn-air batteries

Crystal structure modulation engineering on the lattice scale and charge transport network design on the micro/nano scale work together to endow oxygen electrocatalysts with high reactivity to fully release the capacity of Zn-air batteries (ZABs) as the next-generation green energy storage devices. Metal phosphide-based oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) electrocatalysts with tunable electronic structures, variable valence states, and moderate overpotentials are recognized as the most promising and ideal candidates for air cathodes. The cation substitution strategy overcomes the drawback that single metal phosphides with fewer active sites and high adsorption barriers are not sufficient to achieve satisfactory electrocatalytic performance. In this paper, the Fe2P-Co2P/NPC oxygen electrocatalyst employing lattice cation site substitution engineering and three-dimensional (3D) conductive network encapsulation strategies are constructed to successfully ensure fast electron transfer behavior and safe charge/discharge energy storage. Noteworthy, the presence of Schottky barriers at the interface of the two materials hinders the electron reflux, which promotes a unidirectional flow of electrons, and increases the electron condensation in the OER and ORR processes. Relying on these features, the Fe2P-Co2P/NPC-assembled liquid ZABs achieved power densities, specific capacities, and energy densities of 175.18 mW cm-2, 805.75 mAh gZn-1, and 958.84 Wh kg-1, respectively, and importantly good rate performances and stability were exhibited even under high-current-density operation. The corresponding flexible solid-state ZABs also possesses superior electrochemical activity and mechanical flexibility. This work paves the way for the construction of bifunctional oxygen electrocatalysts with high-speed electron transfer channels, thus advancing the development of wearable electronic devices.

Approaches to Methodological Rationale of Development of Single Backbone Transport Network and Prioritisation of Transport Infrastructure Development Projects

Approaches to Methodological Rationale of Development of Single Backbone Transport Network and Prioritisation of Transport Infrastructure Development Projects

Preparation of multicomponent mixtures to support carbon metrology

The Reference Gas Laboratory (LGR) of Portuguese Institute for Quality (IPQ) is participating in the project – Metrology Support for Carbon Capture Utilization and Storage (MetCCUS) under the new European Partnership on Metrology Program (EPM).The goal of this project is to develop a metrological infrastructure that enables monitoring and detection of carbon dioxide leaks in energy and industrial processes, in transport networks and also allow the support of a better understanding of the life cycle of carbon dioxide.The contribution of LGR involves the preparation of certified reference materials (CRM) to allow the measurement of impurities in CO2 with the associated uncertainties and metrological traceability. The study is focused on the impurities: SO2, H2S, CO, O2 and CH4. This work also involves the study of interferents based on the analytical methods used. These CRM will provide support for the calibration and validation of instrumentation used in carbon capture processes.

Collapse analysis of a masonry arch bridge using the applied element method

Masonry arch bridges constitute a fundamental part of the European transport network. Given their historical relevance and ongoing functional role, often under significantly higher load conditions than originally designed for, a reliable assessment of their load-bearing capacity is essential to understand whether they can guarantee adequate structural performance. To address this need, research efforts have focused on the development of computational methods capable of providing realistic simulations of the structural and collapse behavior of this kind of structures. In this context, the present paper aims to evaluate the application of the recently developed Applied Element Method (AEM) to masonry arch bridges, using the well-known Prestwood bridge (Staffordshire, UK) as a benchmark case study. The bridge was modeled using AEM and loaded until collapse simulating the actual conditions of the in situ test carried out in 1986. Results show consistency, in terms of bearing capacity and collapse mechanism, with the experimental data and previous studies that used other numerical approaches, proving the ability of the Applied Element Method to provide an accurate estimate of the collapse behavior of this kind of structures. AEM’s ability to represent collapse mechanisms involving large displacements, at a reduced computational cost, is especially useful for the design of alert and monitoring systems for structures in a damaged or pre-collapse state.

Standing at the crossroads — ‘En Ḥaẓeva in the Early Iron Age IIA

This paper presents, for the first time, an analysis of the early Iron Age IIA occupation at ‘En Ḥaẓeva. A series of radiocarbon measurements from short-lived samples obtained from the site’s earlier occupation levels (Strata VIII–VII) were all dated to the 10th century BCE. It is noteworthy, that Stratum VII occupies the second half of the 10th century BCE exclusively, with its final phase around 900 BCE. Fixing the site’s absolute chronology has far-reaching implications, enabling the placement of the early Iron Age IIA settlement within the broader historical context. Situated c. 20 kilometres from the most significant copper industry centre in the Levant — Khirbet en-Nahas, ‘En Ḥaẓeva enjoyed a strategic location in the transport network of copper through the Negev Highlands and the Beer-Sheba Valley to the Mediterranean seaports. It is claimed that the economic prosperity related to copper production at Khirbet en-Nahas during the early Iron Age IIA was ‘En Ḥaẓeva’s raison d’être.

Evaluation of robustness in underground networks

Since the development of urban public mass transport in cities, transport infrastructures are a milestone for the economies of the cities and those of their respective regions. The construction of underground systems has seen impressive growth in many transport networks in the past few years, becoming the hinge of mobility in many of the principal cities of the world. Due to the latter and because of the possibility of disruptive events (natural disasters, random failures, and intentional attacks), many scholars and governments have worried about how robust the networks are. For this reason, in this paper we reviewed the robustness of networks by using graph theory tools to analyze and measure them through a new centrality index, called Sum of Weighted Distances Index (SWDI). The index measures the percentage of changes in traveled distances in the event that the node and all edges containing it are disrupted. To evaluate the robustness of a network, we compare the outcomes of SWDI at a standard working configuration and at a degraded one, modeled as a reduction of performance at a certain edge, edge by edge. SWDI is able to show at what edges and nodes of the network the degradation will have the highest impact. Summing up the normalized SWDI outcomes for all the nodes and edges, the final evaluation of the robustness of the network is obtained. Applications to the two case studies of Boston and Barcelona are developed, compared, and discussed, limited to their topology.

Graph neural networks as strategic transport modelling alternative ‐ A proof of concept for a surrogate

AbstractPractical applications of graph neural networks (GNNs) in transportation are still a niche field. There exists a significant overlap between the potential of GNNs and the issues in strategic transport modelling. However, it is not clear whether GNN surrogates can overcome (some of) the prevalent issues. Investigation of such a surrogate will show their advantages and the disadvantages, especially throwing light on their potential to replace complex transport modelling approaches in the future, such as the agent‐based models. In this direction, as a pioneer work, this paper studies the plausibility of developing a GNN surrogate for the classical four‐step approach, one of the established strategic transport modelling approaches. A formal definition of the surrogate is presented, and an augmented data generation procedure is introduced. The network of the Greater Munich metropolitan region is used for the necessary data generation. The experimental results show that GNNs have the potential to act as transport planning surrogates and the deeper GNNs perform better than their shallow counterparts. Nevertheless, as expected, they suffer performance degradation with an increase in network size. Future research should dive deeper into formulating new GNN approaches, which are able to generalize to arbitrary large networks.

The formation of external innovation linkages of the periphery within multiplex regional networks: a multilayer exponential random graph modelling approach

ABSTRACT Innovation in peripheral areas relies more on external linkages to overcome peripherality than in core areas. We study how these linkages are formed, especially through the interaction with diverse networks like transport and investment networks that connect the periphery with external areas. Using data from peripheral Zhejiang, China, we construct a four-layer network with co-patenting and three explanatory layers: transport, investment, and university headquarters-branch linkages. We use multilayer exponential random graph modelling to examine factors driving the formation of the co-patent network, specifically cross-layer interactions between co-patenting and the other three networks. Results show a tendency for the periphery to be linked to the core through co-patenting. All the other three layers have a positive association with the co-patent network, and their intersections show a stronger correlation with the network. This is especially true for the university headquarter-branch network and its intersection with the investment network. The main contribution of this paper is expanding the analysis of peripheral innovation by considering broader intercity networks rather than solely focusing on innovation linkages. Our findings also have policy implications for overcoming innovation constraints in peripheral areas and reducing spatial disparities in Zhejiang and similar regions.

High-speed optical channels of advanced optical transport networks OTN/DWDM. Part 2: Communication range, spectral efficiency and symbol rate.

The series of articles presents analytical materials on the throughput and evolution of modulation formats of OTN/DWDM optical channels (part 1), on the communication range, spectral efficiency and symbol rate of OTN/DWDM optical channels (part 2).

LncRNAs: New players of cancer drug resistance via targeting ABC transporters.

Cancer drug resistance poses a significant obstacle to successful chemotherapy, primarily driven by the activity of ATP-binding cassette (ABC) transporters, which actively efflux chemotherapeutic agents from cancer cells, reducing their intracellular concentrations and therapeutic efficacy. Recent studies have highlighted the pivotal role of long noncoding RNAs (lncRNAs) in regulating this resistance, positioning them as crucial modulators of ABC transporter function. lncRNAs, once considered transcriptional noise, are now recognized for their complex regulatory capabilities at various cellular levels, including chromatin modification, transcription, and post-transcriptional processing. This review synthesizes current research demonstrating how lncRNAs influence cancer drug resistance by modulating the expression and activity of ABC transporters. lncRNAs can act as molecular sponges, sequestering microRNAs that would otherwise downregulate ABC transporter genes. Additionally, they can alter the epigenetic landscape of these genes, affecting their transcriptional activity. Mechanistic insights reveal that lncRNAs contribute to the activity of ABC transporters, thereby altering the efflux of chemotherapeutic drugs and promoting drug resistance. Understanding these interactions provides a new perspective on the molecular basis of chemoresistance, emphasizing the regulatory network of lncRNAs and ABC transporters. This knowledge not only deepens our understanding of the biological mechanisms underlying drug resistance but also suggests novel therapeutic strategies. In conclusion, the intricate interplay between lncRNAs and ABC transporters is crucial for developing innovative solutions to combat cancer drug resistance, underscoring the importance of continued research in this field.

The Adequacy of Cost-Benefit Analysis in the Assessment of Public Value: A Case Study from the Transportation Sector

The complexity of the public value discussion has hindered the development of consensual measurement guidelines for use in public administration practice. This article explores the use of the cost-benefit analysis (CBA) framework in the transportation sector and considers its relevance in assessing public value. A case study is presented on the reconfiguration of a public transport network in the municipality of Arganil, Portugal. The CBA did not fully capture the effects of the network reconfiguration, demonstrating its limitations in assessing public value.

Pt nanoclusters confined in the pores of hollow carbon spheres boost adsorption and electrochemical redox reaction for lithium-sulfur batteries

Sulfur (S) cathode is considered an ideal energy storage material for secondary batteries due to the high specific capacity and energy density. However, the insulating nature of S and lithium sulfide and slow electrochemical reaction kinetics, among many other issues, limit its power and energy output. Precious metals are vigorous catalytic materials and have been applied in various fields. However, the investigation of small-sized precious metal nanoclusters as the catalytic for polysulfide conversion in lithium-sulfur (Li-S) batteries has yet to be deepened. Herein, small-sized Pt nanoclusters are successfully synthesized and confined in the pores of hollow carbon spheres as the host for Li-S batteries cathode. The resultant PtNC@HCS provides the space for storing S and the electron transport network. Meanwhile, the Pt nanoclusters in the pores serve as catalytic sites for adsorbing and accelerating polysulfide conversion, thus effectively suppressing the shuttle effect. As a result, PtNC@HCS exhibits an initial capacity of 1460 mAh g−1 and a reversible capacity of 1316 mAh g−1 at 0.2C, with outstanding capacity retention, which confirms that such precious metal nanocluster catalytic material design effectively can optimize the electrochemical performance of Li-S batteries.