Electric Vehicle Charging Facility Planning Based on Flow Demand—A Case Study

The location of electric vehicle charging facilities is of great significance in promoting the use of electric vehicles. Most existing electric vehicle location models, including the flow refueling location model (FRLM) and its flexible reformulation (FRFRLM), are based on flow demand. At present, these models cannot effectively deal with large-scale traffic networks within a limited time, and there has been little comparison of their relative benefits and limitations. Additionally, there have been few evaluations of the actual construction and location of charging facilities in cities. This paper describes an algorithm that can solve the large-scale transportation network problem within a reasonable time. Using this algorithm, the FRLM and FRFRLM models are compared in a case study focused on Jiading District, Shanghai, China, which provides some direction for the future development of flow demand models. Finally, to evaluate the actual construction of urban charging facilities, this paper presents an algorithm that can map the actual charging facilities to the transportation network, and compares the actual construction situation with the model output. This enables a comprehensive evaluation of the actual construction of charging facilities and provides guidance for future construction.

Percolation of heterogeneous flows uncovers the bottlenecks of infrastructure networks

Whether it be the passengers’ mobility demand in transportation systems, or the consumers’ energy demand in power grids, the primary purpose of many infrastructure networks is to best serve this flow demand. In reality, the volume of flow demand fluctuates unevenly across complex networks while simultaneously being hindered by some form of congestion or overload. Nevertheless, there is little known about how the heterogeneity of flow demand influences the network flow dynamics under congestion. To explore this, we introduce a percolation-based network analysis framework underpinned by flow heterogeneity. Thereby, we theoretically identify bottleneck links with guaranteed decisive impact on how flows are passed through the network. The effectiveness of the framework is demonstrated on large-scale real transportation networks, where mitigating the congestion on a small fraction of the links identified as bottlenecks results in a significant network improvement.

THE OPTIONS OF WASTE HEAT UTILIZATION IN A BUILDING OF MEDICAL PRODUCT’S MANUFACTURE

This article examines the possibilities of using waste heat in a building for the production of medical products. During the production, 6 compressors operate continuously, and the generated excess heat is removed through coolers or partially used in building heating, ventilation and domestic hot water production systems. The aim of this article is to model and evaluate the possibilities of using waste heat after performing the analysis of heat flow demand of all the engineering systems. The pinch method is used to achieve this goal. Heat flows and heat exchanger network are modelled using PinCH 3.0 software. The performed assessment shows that with the help of pinch analysis, in the analysed object it is possible to recover and use more than 20% of waste heat as compared to the initial design variant.

Route Configuration Method for Highway Passenger Hubs from the Perspective of Transportation Integration: A Case Study of Nanjing, China

As a result of transportation integration, the role of highway passenger transport hubs has changed dramatically; these nodes act as important links to construct a seamless regional comprehensive passenger transport system which reflects the coordination and symmetry of public transportation and the integrated transportation system. In order to optimise the efficiency of transportation organisation and improve the quality of passenger transport services, in this study we developed an optimisation method for the allocation of passenger transport hubs based on the analysis of passenger flow demand and spatial distribution. Configuration models of the departure sites of single-station and multi-station hub lines were established according to the service scope of the stations and the relative generalised travel cost, respectively. The overall optimisation method of the route allocation scheme was proposed by checking and optimising the passenger volume of each station. The developed methodology was successfully validated by applying it to the highway passenger transport hub system of Nanjing, China. The proposed methodology is expected to help management agencies and business operators to optimise existing highway passenger bus lines, thereby improving the quality of their services.

The Ecological Water Demand of Schizothorax in Tibet Based on Habitat Area and Connectivity

Water resource regulation is convenient for humans, but also changes river hydrology and affects aquatic ecosystems. This study combined a field investigation and two-dimensional hydrodynamic model (MIKE21) to simulate the hydrodynamic distribution from 1 March to 30 April of 2008–2013 and establish the HDI (habitat depth suitability index) and HVI (habitat velocity suitability index) based on static hydraulic conditions at typical points. Additionally, by using MIKE21 to simulate the hydraulic state in the study area under 20 flow conditions from 530–1060 m3/s, and combining these states with the HCI (habitat cover type suitability index), HDI, and HVI, we simulated the WUA (weighted usable area) and habitat connectivity under different runoff regulation scenarios to study the water requirements of Schizothorax during the spawning period in the Yanni wetland. The results showed the following: (1) the suitable cover type was cobble and rock substrate, with nearby sandy land; furthermore, the suitable water depth was 0.5–1.5 m, and the suitable velocity was 0.1–0.9 m/s. (2) Using the proximity index to analyse the connectivity of suitable habitats, the range of ecological discharge determined by the WUA and connectivity was 424–1060 m/s. (3) Habitat quality was divided into three levels to detail the flow demand further. When the flow was 424–530 m3/s or 848–1060 m3/s, the WUA and connectivity generally met the requirements under natural conditions. When the flow was 530–636 m3/s or 742–848 m3/s, the WUA and connectivity were in a good state. When the flow was 636–742 m3/s, the WUA and connectivity were in the best state. This study complements existing research on the suitability of Schizothorax habitat in Tibet, and introduces the connectivity index to enrich the method for calculating ecological water demand, providing a reference for resource regulation and the protection of aquatic organisms.

Effect of Oil Supply Pressure on the Force Coefficients of a Squeeze Film Damper Sealed With Piston Rings

Squeeze film dampers (SFDs) aid to both reduce rotor dynamic displacements and to increase system stability. Dampers sealed with piston rings (PR), common in aircraft engines, are proven to boost damping generation, reduce lubricant flow demand, and prevent air ingestion. This paper presents the estimation of force coefficients in a short length SFD, PR sealed, and supplied with a light lubricant at two feed pressures, Pin-1 ∼ 0.69 barg and Pin-2 ∼ 2.76 barg, i.e., low and high. Two pairs of PRs are installed in the test SFD, one set has flow conductance CS1 = 0.56 LPM/bar, whereas the other pair has CS2 = 0.89 LPM/bar. The second set leaks more as it has a larger slit gap. Dynamic load tests show that both dampers, having seal flow conductances differing by 60%, produce damping and added mass coefficients of similar magnitude, differing by at most 20%. Other experiments quantify the effect of lubricant supply pressure, Pin-1 and Pin-2, on the dynamic film pressure and force coefficients of the PR-SFD. The damper configuration with CS1 and operating with the high Pin-2 shows ∼20% more damping and added mass coefficients compared with test results for the damper supplied with Pin-1. Film pressure measurements show that the air ingestion and oil vapor cavitation coexist for operation at the low Pin-1. Computational predictions accounting for the feed holes in the physical model agree with the experimental coefficients. On the other hand, predictions from classical formulas for an idealized damper geometry, fully sealed at its ends, largely overpredict the measured force coefficients.