How to resolve the contradiction between driving safety and lighting energy conservation in a highway tunnel? − An experiment on linear guiding system

Characteristics of office lighting energy consumption and its impact on air conditioning energy consumption

Conservation of light energy in photosynthesis is possible only in hydrated photoautotrophs. It requires complex biochemistry and is limited in capacity. Charge separation in reaction centres of photosystem II initiates energy conservation but opens also the path to photooxidative damage. A main mechanism of photoprotection active in hydrated photoautotrophs is controlled by light. This is achieved by coupling light flux to the protonation of a special thylakoid protein which activates thermal energy dissipation. This mechanism facilitates the simultaneous occurrence of energy conservation and energy dissipation but cannot completely prevent damage by light. Continuous metabolic repair is required to compensate damage. More efficient photoprotection is needed by desiccation-tolerant photoautotrophs. Loss of water during desiccation activates ultra-fast energy dissipation in mosses and lichens. Desiccation-induced energy dissipation neither requires a protonation reaction nor light but photoprotection often increases when light is present during desiccation. Two different mechanisms contribute to photoprotection of desiccated photoautotrophs. One facilitates energy dissipation in the antenna of photosystem II which is faster than energy capture by functional reaction centres. When this is insufficient for full photoprotection, the other one permits energy dissipation in the reaction centres themselves.

According to the characteristics of traffic accidents of long highway tunnel, this paper proposes a method to identify black spots based on improvable accident of tunnel environment. On the basis of the relationship of traffic accident and long highway tunnel system components, including the driver, the vehicle and the tunnel environment, accidents are classified into seven categories, and this paper only considers four categories relating to tunnel environment. The degree of membership of each accident in the tunnel environment component is used to represent the ability of accidents by tunnel environment improvement. Each accident is weighted by its ability. Then, the method of the equivalent of accident frequency and accident rate is used to identify black spots. Finally, the Kaoyishan tunnel in Beijing-zhuhai freeway in China was applied to analyze black spots using this method. The results show that

Investigating the uniqueness of crash injury severity in freeway tunnels: A comparative study in Guizhou, China

Skid resistance of cement concrete pavement in highway tunnel: A review

Assessment of control strategy of adaptive façades for heating, cooling, lighting energy conservation and glare prevention

The low luminance and the monotony of highway tunnels are likely to cause drivers to experience a visual illusion while driving. Drivers tend to underestimate their speed and thus are exposed to a higher risk of relatively severe traffic accidents. Finding a low-cost way to reduce this visual illusion and to improve traffic safety is a challenge for current highway tunnel operations. High-frequency visual information can make a driver overestimate speed; low-frequency visual information may induce a driver to underestimate speed. However, quantitative investigations of the influence of visual information of various frequencies and luminance levels on drivers' speed perception are lacking. This paper describes a driving simulation model created with Autodesk's 3ds Max modeling software and tests carried out with simulators and E-Prime research software. The mechanisms of speed perception and reaction time were studied to consider the effect of visual information with high frequencies and with combined high and low frequencies under different luminance levels (100%, 50%, and 25% of standard luminance). The test results revealed that speed overestimation was caused mainly by high-frequency visual information. This overestimation could be reduced by combining high-frequency visual information with low-frequency visual information. With higher luminance, speed overestimation was lessened and drivers' reaction time was shorter. It is suggested that visual information with combined frequencies be employed to control drivers' illusions of speed and to enhance traffic safety.

Highway tunnel sections are prone to accidents. In order to reduce safety risk factors generated by tunnels, strict speed limit is implemented in highway tunnels. At present, there is still a lack of research on speed limit standards for expressway tunnel sections.Firstly, this paper analyzes the general situation of highway speed limit in China and abroad, the influencing factors of highway tunnel speed limit settingf, and the driving process into the tunnel.Then a speed limit setting model of highway tunnel considering the constraint conditions of energy saving and emission reduction is proposed, based on the serial influencing factor model, the highway tunnel speed limit setting model is determined by taking the road conditions, traffic conditions, energy consumption and emission factors and environmental conditions into comprehensive consideration and combining with the analytic hierarchy process.Finally, the speed limit scheme of highway tunnel section with the consideration of energy consumption conservation and carbon emmission redectuon is put forward, and some suggestions for setting conditions and constraints of the speed limit scheme are put forward.The results show that the method can be operated and the results obtained are reliable, which can be used as an effective method for the implementation of energy conservation, emission reduction and safety scheme in the field of highway.

With the rapid development of the national economy, China’s transportation industry is experiencing accelerated development, and, at the same time, the number of long tunnels is constantly increasing. In order to examine the influence of jet fan spacing on gas transport law during the construction of long highway tunnels, this study used the Baima Highway Tunnel in Sichuan as an engineering prototype and established a numerical tunnel ventilation model based on Fluent numerical simulation software. The gas transport characteristics of jet fans in tunnels at different spacings (200 m, 400 m, 600 m, and 800 m) were studied. The results showed that with the increase in jet fan spacing (200 m, 400 m, 600 m, and 800 m), the gas concentration at the tunnel face showed a trend of decreasing and then increasing. Moreover, by analyzing the gas distribution cloud map and the wind flow line diagram, it was determined that the ventilation system effect was the best when the jet fan spacing was 600 m, which met the requirements of a gas concentration of less than 0.5% at the tunnel face and a minimum wind speed of 0.25 m/s. At the same time, according to the optimal spacing for the optimization of the site ventilation system, it was observed that after the ventilation was stabilized (after 600 s), the minimum value of the gas concentration in the left and right tunnel holes diminished from 0.38% to 0.31% and from 0.41% to 0.31%, with rates of reduction of 18.42% and 24.39%, respectively. This indicated that after optimizing the ventilation system at the tunnel site, the concentration significantly decreased compared with before the optimization. Moreover, when the jet fan spacing was 600 m compared with 200 m and 400 m, the annual energy savings were 1900.8 MW·h and 950.4 MW·h, respectively. The research results clarified the optimal layout parameters of jet fans in the Baima Highway Tunnel, providing a reference for the rational layout of jet fans in long-distance tunnels. In addition, the results of this study provide an important theoretical basis for the gas prevention and safe construction of long highway tunnels. Furthermore, this study contributes to research in energy conservation, emission reduction, and sustainable development of energy in the ventilation process during tunnel construction.

Due to the harsh environment of highway tunnels and frequent breakdowns of various detection sensors and surveillance devices, the operational management of highway tunnels lacks effective data support. This paper analyzes the characteristics of operational surveillance data in highway tunnels. It proposes a multimodal information fusion method based on CNN–LSTM–attention and designs and develops a digital twin for highway tunnel operations. The system addresses issues such as insufficient development and coordination of the technical architecture of operation control systems, weak information service capabilities, and insufficient data application capabilities. The system also lacks intelligent decision-making and control capabilities. The developed system achieves closed-loop management of “accurate perception–risk assessment–decision warning–emergency management” for highway tunnel operations based on data-driven approaches. The engineering demonstration application underscores the system’s capacity to enhance tunnel traffic safety, diminish tunnel management costs, and elevate tunnel driving comfort.

The impact of lighting and longitudinal slope on driver behaviour in underwater tunnels: A simulator study

Electric lighting of buildings in the United States consumes over 20% of the nation's primary electricity and is second only in magnitude to heating, ventilation and air conditioning systems. This installed lighting base is generally inefficient and is characterized by relatively low performance especially when compared to other building systems. While substantial opportunities for improving overall lighting system efficiency exist, the pathway to achievement of this goal is less clear. Lighting research and development conducted by the US Department of Energy's (DOE), Office of Energy Efficiency and Renewable Energy's (EERE), Building Technologies Program (BT) addresses this national issue and aggressively pursues a number of broad research areas that promise to yield significant increases in overall lighting system efficiency. Implementation of a successful program in lighting energy conservation depends upon a detailed assessment of energy consumption trends by lighting technology. The results of several years of research are presented that describe electricity consumption by market sector, application and lamp type. Following this lighting market assessment, an overview of the DOE's ongoing lighting research and development (LR&D) program portfolio linked to the market assessments is provided. Individual program contributions toward achieving ambitious lighting energy conservation goals are described. The BTS portfolio includes research in three broad areas: (1) light source and electronics, (2) fixtures, controls and distribution systems, and (3) human factors. An overview of each technical objective is provided, as well as a timeline for achieving specific energy conservation goals.

Ventilation system of highway tunnel is the key factors of keeping normal operations. In addition to the normal operation of keeping tunnel environment, the need to control the spread of smoke and meet requirements of escape and rescue work in fire case. This article describes the design guidelines of emergency ventilation system for different types of road tunnel. This article will help long highway tunnel ventilation system to improve the ability to deal with fire, improve operational safety.

The relationship between photosynthetic energy conservation and thermal dissipation of light energy is considered, with emphasis on organisms which tolerate full desiccation without suffering photo-oxidative damage in strong light. As soon as water becomes available to dry poikilohydric organisms, they resume photosynthetic water oxidation. Only excess light is then thermally dissipated in mosses and chlorolichens by a mechanism depending on the protonation of a thylakoid protein and availability of zeaxanthin. Upon desiccation, another mechanism is activated which requires neither protonation nor zeaxanthin although the zeaxanthin-dependent mechanism of energy dissipation remains active, provided desiccation occurs in the light. Increased thermal energy dissipation under desiccation finds expression in the loss of variable, and in the quenching of, basal chlorophyll fluorescence. Spectroscopical analysis revealed the activity of photosystem II reaction centres in the absence of water. Oxidized beta-carotene (Car+) and reduced chlorophyll (Chl-), perhaps ChlD1 next to P680 within the D1 subunit, accumulates reversibly under very strong illumination. Although recombination between Car+ and Chl- is too slow to contribute significantly to thermal energy dissipation, a much faster reaction such as the recombination between P680+ and the neighbouring Chl- is suggested to form the molecular basis of desiccation-induced energy dissipation in photosystem II reaction centres. Thermal dissipation of absorbed light energy within a picosecond time domain deactivates excited singlet chlorophyll, thereby preventing triplet accumulation and the consequent photo-oxidative damage by singlet oxygen.

Exploring factors affecting injury severity of crashes in freeway tunnels