Risk assessment of subway station fire by using a Bayesian network-based scenario evolution model

Subway station fires frequently result in massive casualties, economic losses and even social panic due to the massive passenger flow, semiconfined space and limited conditions for escape and smoke emissions. The combination of different states of fire hazard factors increases the uncertainty and complexity of the evolution path of subway station fires and causes difficulty in assessing fire risk. Traditional methods cannot describe the development process of subway station fires, and thus, cannot assess fire risk under different fire scenarios. To realise scenario-based fire risk assessment, the elements that correspond to each scenario state during fire development in subway stations are identified in this study to explore the intrinsic driving force of fire evolution. Accordingly, a fire scenario evolution model of subway stations is constructed. Then, a Bayesian network is adopted to construct a scenario evolution probability calculation model for calculating the occurrence probability of each scenario state during subway station fire development and identifying critical scenario elements that promote fire evolution. Xi’an subway station system is used as a case to illustrate the application of Bayesian network-based scenario evolution model, providing a practical management tool for fire safety managers. The method adopted in this study enables managers to predict fire risk in each scenario and understand the evolution path of subway station fire, supporting the establishment of fire response strategies based on “scenario–response” planning.</p

Research Progress on Flexibility Modification of Coal-Fired Generating Units

[Introduction] The strategic goal of "carbon peaking and carbon neutrality" has increased the demand for new energy power grid integration, so it is necessary to improve the flexible operation capacity of coal-fired generating units. [Method] This paper introduced the flexible transformation technology and common evaluation indicators of existing coal-fired units in detail. Flexibility transformation mainly included condensate throttling technology, coupled biomass co-combustion transformation technology of coal-fired units, flexibility technology of pulverizing system of coal-fired units, etc.; Common evaluation indicators for the flexibility of coal-fired generating units included: the power consumption rate of the generator set plant, the thermal efficiency of the boiler, the standard coal consumption rate of the generator set, etc. On this basis, this paper summarized and analyzed the flexibility transformation technology and evaluation indexes. [Result] Finally, the paper puts forward seven kinds of the technology development direction and relevant suggestions of coal-fired generating units. [Conclusion] The structural improvement of original generating units, the introduction of multi-form new energies and the coordinated regulation design of multi-heat storage will be the main direction of subsequent development. It is expected that paper can provide reference for subsequent coal-fired generating units to adapt to "dual carbon" energy planning

A Linearly and Circularly Polarization-Reconfigurable Leaky Wave Antenna Based on SSPPs-HSIW

In this manuscript, a reconfigurable leaky wave antenna is proposed with linearly polarized and circularly polarized properties, which is composed of two layers with feeding waveguide and radiation elements. The bottom layer is a half-mode substrate integrated waveguide etched with a spoof surface plasmon polaritons structure as a high-dispersion feeding waveguide to excite 8 circular patches as radiation elements in the top layer. In a unit element, the horizontal linear polarization (HLP) and right-hand circular polarization (RHCP) radiation are switched using a p-i-n diode crossing a slot of a circular metal patch. HLP performance is achieved as the p-i-n diode is switched off, and RHCP is achieved as the p-i-n diode is switched on. The measured results verify the design theory and the simulated results. Over the working band of 10.4~12.8 GHz, the proposed antenna can radiate scanning beams covering about a 73° region, including the broadside direction with HLP and RHCP

Impact of Political Connection Strength on the Internationalization Outcome of Chinese Firms: Perspectives from Market Exploration and Technology Acquisition

Although the role of a home country&rsquo;s government in firms&rsquo; internationalization processes has been investigated, there is a gap in the literature concerning the effectiveness of the government&rsquo;s effort. Based on the data of 1996 Chinese listed firms, this study investigates how the strength of Chinese firms&rsquo; political connection with their home country government impacts the outcomes of their internationalization activities. These activities are classified into market exploration and technology acquisition. We establish an index to measure the firms&rsquo; political connection strength and find that it exhibits a bimodal distribution, which indicates that some firms maintain a close relationship with the government, while the business activities of others are distant from the government. The strength of the political connection has different moderating effects on firms&rsquo; internationalization processes when either the international market context or the firms&rsquo; internationalization activities vary. A strong political connection is beneficial for firms to explore the markets and acquire beneficial technology from developed countries. Compared with its role in exploring international markets, political connection plays a more significant moderating role in augmenting the positive effect of international technology acquisition on firms&rsquo; innovation capability. Therefore, Chinese firms may perform better in the internationalization process if they maintain a close relationship with the Chinese government, which engages in promoting the internationalization of domestic firms through an array of policies that may compensate for the firms&rsquo; disadvantages. Our results show the mechanism through which emerging countries&rsquo; governments use directives and incentives to facilitate the internationalization of domestic firms

Analysis on the Enterprises’ Innovation Quality Based on the Patent Value: A Comparison between Public and Private Enterprises in China

To investigate Chinese enterprises&rsquo; innovation quality and examine how it is determined by the enterprise ownership, this paper uses about 73.8 thousand invention patents applied by Chinese enterprises during 1985&ndash;2011 in estimating patent return based on the renewal period. We take patent return to be the measurement of innovation quality, and make a comparison between public and private enterprises. We find that the innovation quality of public enterprises is improved after restructuring, but is still lower than that of private enterprises. We may find the causes of the innovation quality differences from the allocation efficiency of R&amp;D resources. Monopolized enterprises own higher innovation quality by monopolizing industry resources, which leads to a low R&amp;D resources allocation efficiency. In comparison, the R&amp;D resources allocation efficiency of public enterprises in the competitive industry is higher than that in monopolized enterprises. R&amp;D resources allocation efficiency is generally inversely proportional to the public owned level, and proportional to the market competition level. This study generates an important policy implication, that is, the social R&amp;D resources allocation efficiency of China would be improved by disposing part of R&amp;D resources monopolized by public research institutes and public enterprises to private enterprises

Effects of green policies on household transport and energy consumption in Europe: a literature review

The European Union (EU) has formulated several rounds of energy goals to comply with the Paris Agreement. This chapter reviews and evaluates the effectiveness of EU green policies that aim at encouraging households to reduce CO2 emissions from both transportation and home energy consumption/production perspectives. The literature on energy policy, energy economics, and (applied) social and environmental psychology is reviewed and categorized into household long-term transport decisions (i.e., car ownership, new mobility tools, modeling) and household in-home behavior (i.e., prosumer, energy conservation behavior, household perception, antecedent/consequence strategies). Particular attention is given to the following evaluation criteria: (1) to what extent did the green policies result in behavioral change, reduction in conventional energy usage, and/or an increase of renewable energy production; and (2) were the effects maintained over a longer period of time

A Tunable Constant-Absolute-Bandwidth Bandpass Filter with Switchable Ability

This paper presents a tunable bandpass filter (BPF) with constant absolute bandwidth (CABW) and switchable properties. The BPF is performed by using a tri-mode cross-shape resonator (CSR) loaded with varactors. The CABW and switchable ability are achieved by adjusting the resonant frequencies. Meanwhile, the two transmission zeros (TZs) produced by center-loaded stubs strengthen the skirt selectivity in the on-state and the isolation in the off-state. For demonstration, a tri-pole switchable BPF with three control voltages is implemented and verified, and the control mechanism is simple. In the on-state, it exhibits a 120 MHz, 3 dB CABW with the measured insertion loss (IL) of 2.2–2.5 dB in the tuning range of 0.816–1.188 GHz. In the off-state, the measured isolation is better than 27 dB

Vibration isolation effect study of in-filled trench barriers to train-induced environmental vibrations

\u3cp\u3eAn in-filled trench barrier is usually used to reduce the damages from train-induced environmental vibrations. To find the vibration isolation effect of an in-filled trench barrier, this paper analyses the reflection coefficients and transmission coefficients of the Rayleigh wave at the interface between in-filled trenches and the soil. In our calculation formulas of ground vibrations, a single point and a single frequency excitation, as well as multi-point and multi-frequency excitation, are simultaneously derived in a soil-in-filled-trench system. Using these formulas and a numerical analysis, the effects of an in-filled trench barrier on the environmental vibrations induced by running trains are analyzed. The results show that the reflection coefficients increase, while the transmission coefficients decrease, with the density and elastic modulus of the in-filled material. The vibration isolation effect is clearly better than that without trenches. In a certain width range, the transmission coefficient and vertical acceleration levels decrease with the increase of trench width. The influences of the transmission coefficient and the vibration isolation effects are not clear with the trenches’ depth variation. The vertical vibrations of the ground pick-up point are all smaller than those without in-filled trenches.\u3c/p\u3

HR38, an ortholog of NR4A family nuclear receptors, mediates 20-hydroxyecdysone regulation of carbohydrate metabolism during mosquito reproduction

The Aedes aegypti mosquito is the principal vector for many dangerous human viral diseases. Carbohydrate metabolism (CM) is essential for supplying the energy necessary for host seeking, blood digestion and rapid egg development of this vector insect. The steroid hormone 20-hydroxyecdysone (20E) and the ecdysone receptor (EcR) are important regulators of CM, coordinating it with female reproductive events. We report here that the NR4A nuclear receptor AHR38 plays a critical role in mediating these actions of 20E and EcR. AHR38 RNA interference (RNAi) depletion in female mosquitoes blocked the transcriptional activation of CM genes encoding phosphoglucomutase (PGM) and trehalose-6-phophate synthase (TPS); it caused an increase of glycogen accumulation and a decrease of the circulating sugar trehalose. This treatment also resulted in a dramatic reduction in fecundity. Considering that these phenotypes resulting from AHR38 RNAi depletion are similar to those of EcR RNAi, we investigated a possible connection between these transcription factors in CM regulation. EcR RNAi inhibits the AHR38 gene expression. Moreover, the 20E-induced EcR complex directly activates AHR38 by binding to the ecdysone response element (EcRE) in the upstream regulatory region of this gene. The present work has implicated AHR38 in the 20E-mediated control of CM and provided new insight into mechanisms of 20E regulation of metabolism during female mosquito reproduction