This study evaluates the energy-saving potential of hollow glass windows integrated with reflective aluminum foil louvers, tailored for hot-summer, cold-winter regions. The reflective integration minimizes solar absorption and bolsters insulation. Experimental results indicate a 14.9% reduction in heat transfer coefficient (K) (from 2.427 to 2.066 W/[m2·K]) and a 20% decrease in shading coefficient (SC) (from 0.30 to 0.24) compared to standard louvers in the closed position. Furthermore, a coupled effect between air layer thickness (δ) and louver angle (θ) on K is observed, with smaller δ intensifying θ’s influence. The reflective system demonstrates superior thermal performance at a modest cost increase of 3.4%, rendering it viable for energy-efficient applications.
Jennifer Gómez, Jessica Paredes, Eduardo Ortigoza
et al.
Lithium-ion batteries are essential for electric vehicles, requiring critical resources such as lithium and cobalt. Paraguay’s integration into the electric vehicle supply chain presents an opportunity to leverage its renewable energy and strategic location. This study evaluates potential partners for Paraguay to establish a lithium-ion battery and electric vehicle assembly plant in the Chaco region. A multi-criteria decision analysis using the Analytic Hierarchy Process and expert opinions assessed Argentina, Brazil, Bolivia, and Chile based on economic, energy, environmental, social, political, and geopolitical factors. The results indicate Chile as the most favorable partner (29.5%), followed by Argentina (25.9%), Bolivia (22.8%), and Brazil (21.6%). Chile’s strengths lie in its environmental policies and political stability, while Argentina offers logistical advantages and resource availability. The findings highlight strategic pathways for Paraguay’s integration into the electric vehicle supply chain and the importance of targeted collaboration to enhance regional lithium-ion battery production and commercialization.
Rock joints always have a smaller strength, and it plays an important influence on the overall strength of rock mass. The mechanical behavior of rock joints is mainly governed by the surface topography, normal stress, and failure degree. In this study, a series of direct shear tests for four different rough rock joints under five normal stresses was carried out. The shear and normal stiffnesses were first determined, and the shear shrinkage effect was represented by a shear-normal coupling coefficient. Assuming that the strength of the joint is composed of frictional and cohesive parts, the evolutions of cohesion, friction angle with joint roughness coefficient (JRC), and plastic shear displacement are obtained. The dilatancy behavior is described by the dilation angle, which is considered a function of JRC, plastic shear displacement, and normal stress. A cohesive-frictional elastoplastic constitutive model is hence proposed. The theoretical curves under constant normal stress conditions of the proposed model are in good agreement with the experimental results. The shear behaviors under constant normal stiffness and constant normal displacement conditions can be predicted using the new constitutive model.
Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Purpose – The design goal for the tracking interval of high-speed railway trains in China is 3 min, but it is difficult to achieve, and it is widely believed that it is mainly limited by the tracking interval of train arrivals. If the train arrival tracking interval can be compressed, it will be beneficial for China's high-speed railway to achieve a 3-min train tracking interval. The goal of this article is to study how to compress the train arrival tracking interval. Design/methodology/approach – By simulating the process of dense train groups arriving at the station and stopping, the headway between train arrivals at the station was calculated, and the pattern of train arrival headway was obtained, changing the traditional understanding that the train arrival headway is considered the main factor limiting the headway of trains. Findings – When the running speed of trains is high, the headway between trains is short, the length of the station approach throat area is considerable and frequent train arrivals at the station, the arrival headway for the first group or several groups of trains will exceed the headway, but the subsequent sets of trains will have a headway equal to the arrival headway. This convergence characteristic is obtained by appropriately increasing the running time. Originality/value – According to this pattern, there is no need to overly emphasize the impact of train arrival headway on the headway. This plays an important role in compressing train headway and improving high-speed railway capacity.
Transportation engineering, Railroad engineering and operation
Maglev vehicles apply the entire vehicle load uniformly onto bridges through levitation forces. In assessing the dynamic characteristics of the maglev train–bridge coupling system, it is reasonable to simplify the distributed levitation force as a concentrated force. This article theoretically derives the analytical response of bridge dynamics under the action of a single constant force and conducts numerical simulations for a moving single constant force and a series of equally spaced constant forces passing over simply supported beams and two-span continuous beams, respectively. The topic of discussion is the response of bridge dynamics when different degrees of force concentration are involved. High-precision displacement and acceleration sensors were utilized to conduct tests on the Shanghai maglev line to verify the accuracy of the simulation results. The results indicate that when simplifying the distributed levitation force into a concentrated force model, a frequency ratio can be used to analyze the conditions for resonance between the train and the bridge and to calculate the critical speed of the train; the levitation distribution force of a high-speed maglev vehicle can be simplified into four groups of concentrated forces based on the number of levitation frames to achieve sufficient accuracy, with the dynamic response of the bridge being close to that under distributed loads.
[Objective] To compensate for the preset turnout safety gap between track beam and switch beam of the mobile turnout in the suspended monorail transit system, ensure reliable locking when turnout is in place, and improve the safety and passenger comfort when train passing through turnout area, an integrated mechanism for locking and compensation is proposed, where the locking and compensating functions share a common power source, meeting the sequential requirements for locking before compensation after the turnout is in place. [Method] The current application status of suspended monorail turnouts and the main existing problems are introduced, and the application scenarios are analyzed. The design composition of the locking and compensation mechanism between the suspended track beam and the turnout beam is presented, along with an analysis of the motion working principle of the mechanism. [Result & Conclusion] The proposed locking and compensation mechanism has a compact overall external structure, meeting the installation space constraints between the suspended monorail mobile turnout beam and the track beam. Through the spatial layout design of the integrated linkage rod, the mechanism achieves reliable locking between beams, seam compensation between the turnout beam and the track beam, and fulfills the sequential requirements for locking before compensation.
Bioinspired superhydrophobic surfaces have attracted many industrial and academic interests in recent years. Inspired by unique superhydrophobicity and anisotropic friction properties of snake scale surfaces, this study explores the feasibility to produce a bionic superhydrophobic stainless steel surface via laser precision engineering, which allows the realization of directional superhydrophobicity and dynamic control of its water transportation. Dynamic mechanism of water slid-ing on hierarchical snake scale structures is studied, which is the key to reproduce artificially bioinspired multifunctional materials with great potentials to be used for water harvesting, droplet manipulation, pipeline transportation, and vehicle acceleration.
Abstract In the history of bridge engineering, demand has always been the primary driving force for development. Driven by the huge demand for construction since China’s reform and opening-up, Chinese bridge has leapt forward both quantitatively and qualitatively in three major stages, by completing the transition from “follower” to “competitor,” and finally to “leader.” A new future is emerging for Chinese bridge engineering. As an important part of China’s transportation infrastructure, the bridge engineering industry is facing challenges in this new era on how to support the construction of a new form of transportation. This paper provides a summary of the status of bridge technology in China, based on a basic analysis of stock demand, incremental demand, and management demand. It is our belief that the Chinese bridge engineering industry must fulfill three outstanding requirements: construction efficiency, management effectiveness, and long-term service. Intelligent technology based on information technology provides a new opportunity for innovation in bridge engineering. As a result, the development path of bridge engineering needs to be changed. This paper puts forward the idea of developing a third-generation bridge project that is characterized by intelligence, and discusses this project’s implications, development focus, and plan. In this way, this work provides a direction for the improvement of the core competitiveness of China’s bridge engineering industry.
Current transportation fuels derived from petroleum can also be made from microbial systems. In particular, oleaginous yeast have naturally evolved high flux pathways for fatty acids in the form of neutral lipids, which can be converted into a variety of drop-in fuels. Here, we describe the recent advances in the use of the four most popular oleaginous yeasts for making lipids and other potential fuels - Yarrowia lipolytica, Lipomyces starkeyi, Rhodosporidium toruloides, and Cutaneotrichosporon oleaginosus. The paper is divided into three major sections focusing on (1) the important natural complex phenotypes of each yeast; (2) the development of metabolic engineering tools for each yeast; and (3) demonstrations of metabolic engineering in each yeast. At the end of each section, we provide our assessment, of which yeast is most promising in the near and long term for bioenergy production.
Abstract Organic solvent nanofiltration (OSN) membrane is an embryonic technology in chemical engineering for simultaneously purifying organic solvents and recycling nano-scale molecules. Although the inherent nano-cavity cyclodextrins (CDs) as powerful molecular hosts in supramolecular science ensure promise for separation technology, the limited synthesis toolbox and material choice impede the CDs deployment in membrane separations, especially for OSN applications. Herein, biocompatible β-cyclodextrin (β-CD) and mussel-inspired polydopamine (pDA) were discovered as the building blocks to simultaneously construct OSN membranes assisted by the host-guest interactions of supramolecular chemistry and hydrogen-bonds via one-step “green” process. Honeycomb microstructures were formed in this process, which adds the molecular transportation pathways. Such biopolymer membranes can remain extraordinarily stable in organic solvent environments, whilst achieving high rejection against angstrom-sized molecule with different charges toward environmental and energy benefits.
Vessels face uncertain factors during a voyage, such as bad weather and harsh sea conditions along a route in container liner shipping. As such, the real vessel speed during each leg of a voyage often deviates from the planned one, which may lead to fluctuations in vessel schedule and bunker consumption. This paper investigates the problem of vessel scheduling and bunker management with speed deviations (VSBMSD) for liner shipping in the presence of collaborative agreements. By establishing the worst-case scenario of the maximum bunker consumption function with vessel sailing speed as an independent variable, we develop a mixed-integer nonlinear programming model to minimize the total liner shipping route service cost. A piecewise linear secant approximation method is designed, and then a CPLEX solver is used to solve the problem. The results of the computational experiments conducted for the AEMX route indicate that VSBMSD in the presence of collaborative agreements can enable shipping companies to design vessel schedules reasonably and reduce the total cost of liner shipping route service by at least 2.95% compared to the results from similar studies.
Large-scale activities such as the Winter Olympics are usually held in areas with low temperature or other harsh environments, which greatly affects the spectating experience of pedestrians. In order to improve the travel efficiency and reduce the safety risk of pedestrians, an adaptive information-distribution strategy of VMS (variable message sign) for road networks is proposed to guide the pedestrians. In the proposed strategy, the dynamic feedback mechanism between the VMS information distribution and the state of crowded pedestrians is established, and the dynamic optimization model of the VMS information release layout is formulated. To evaluate the effectiveness of the strategy, a multiagent-based simulation method is proposed. Through numerical simulation, it is found that the guidance strategy can improve the movement efficiency by adjusting releasing duration of VMS information or improving the information obedience rate of pedestrians. In this paper, a large-scale competition area in the Xiaohaituo Mountain in Beijing was taken as an example to simulate the scenarios of ingress and egress with and without the strategy. The results show that the average walking time and the road congestion can be significantly reduced in the road network with the strategy, and the proportion of pedestrians with shorter travel time can be increased. Therefore, the research can provide theoretical foundation and data support for managers to guide passenger flows and improve the spectating experience.
Transportation engineering, Transportation and communications
Abstract Low rate of extracellular electron transfer (EET) of exoelectrogens was a major bottleneck in restricting the performance of the microbial fuel cell (MFC) from practical applications. We used synthetic biology approaches (promoter and ribosome binding site (RBS) engineering, and cell surface engineering) to rationally design Shewanella oneidensis for enhanced flavins biosynthesis and transportation in a hydrophobic chassis to boost its EET rate and performance. Graphene oxide (GO) was subsequently used to construct an engineered Shewanella-reduced GO (rGO) 3D self-assembled biohybrid, which dramatically enhanced the thickness and cell numbers in the electroactive biofilm on the anode. Meanwhile, the absorption of flavins on the rGO sheets could not only enhance the π-π interaction, but also increase the local concentration of flavins, which could enhance electron shuttle (flavins)-mediated EET rate in the anodic biofilm. As a result, the maximum output power density reached 2.63 W/m2 (~18.8-folds higher than that of the wild-type S. oneidensis), the highest record of the electricity output of MFCs inoculated with S. oneidensis. Meanwhile, the inward current density of this 3D self-assembled biohybrid biofilm reached 18.78 A/m2.
Part I: Theory -- Historical Overview -- Introduction to the Theory of Games -- Repeated Games -- Multistage Games -- Zero-Sum Differential Games -- Nonzero-Sum Differential Games -- Evolutionary Games -- Mean-Field Games -- Stochastic Games -- Learning in Games -- Network Games -- Cooperative Dynamic Games -- Numerical Methods -- Part II: Applications -- Part IIA: Economics -- Resource Economics -- Environment Economics and Climate Change -- Industrial Organization. Macroeconomics -- Energy Markets -- Health Economics -- Auctions -- Mechanism Design -- Part IIB: Management Science -- Operations Management -- Marketing -- Finance -- Accounting -- Part IIC: Engineering -- Robust Designs -- Aerospace -- Transportation -- Security -- Power Systems & Smart Grids -- Communications Networks (Pricing, Congestion Control, Routing, Flow Control) -- Part IID: Pursuit-Evasion Games -- Part IIE: Biology (Applications of Evolutionary Game Theory) -- Part IIF: Social Networks. .
Classifying and counting vehicles in road traffic has numerous applications in the transportation engineering domain. However, the wide variety of vehicles (two-wheelers, three-wheelers, cars, buses, trucks etc.) plying on roads of developing regions without any lane discipline, makes vehicle classification and counting a hard problem to automate. In this paper, we use state of the art Convolutional Neural Network (CNN) based object detection models and train them for multiple vehicle classes using data from Delhi roads. We get upto 75% MAP on an 80-20 train-test split using 5562 video frames from four different locations. As robust network connectivity is scarce in developing regions for continuous video transmissions from the road to cloud servers, we also evaluate the latency, energy and hardware cost of embedded implementations of our CNN model based inferences.