Modernisation of a railway tunnel for high speed. Case study – Romania

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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Investigation of a loess-mudstone landslide and the induced structural damage in a high-speed railway tunnel

Bulletin of Engineering Geology and the Environment ◽

10.1007/s10064-019-01711-y ◽

2020 ◽

Vol 79 (5) ◽

pp. 2201-2212

Author(s):

Shunhua Zhou ◽

Zhiyao Tian ◽

Honggui Di ◽

Peijun Guo ◽

Longlong Fu

Keyword(s):

Structural Damage ◽

High Speed ◽

Railway Tunnel ◽

High Speed Railway

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Removing W Polymer Residue from BEOL Structures Using DSP+ (Dilute Sulfuric-Peroxide-HF) Mixture – A Case Study

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.195.128 ◽

2012 ◽

Vol 195 ◽

pp. 128-131 ◽

Cited By ~ 1

Author(s):

Hun Hee Lee ◽

Min Sang Yun ◽

Hyun Wook Lee ◽

Jin Goo Park

Keyword(s):

High Speed ◽

Semiconductor Device ◽

Environmental Issues ◽

Low Power Consumption ◽

Device Performance ◽

Metal Gate ◽

Feature Size ◽

High K ◽

Removal Of Metal

As the feature size of semiconductor device shrinks continuously, various high-K metals for 3-D structures have been applied to improve the device performance, such as high speed and low power consumption. Metal gate fabrication requires the removal of metal and polymer residues after etching process without causing any undesired etching and corrosion of metals. The conventional sulfuric-peroxide mixture (SPM) has many disadvantages like the corrosion of metals, environmental issues etc., DSP+(dilute sulfuric-peroxide-HF mixture) chemical is currently used for the removal of post etch residues on device surface, to replace the conventional SPM cleaning [. Due to the increased usage of metal gate in devices in recent times, the application of DSP+chemicals for cleaning processes also increases [.

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The Calculation of Train Slipstreams on Platform of Underground High-Speed Rail Station

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.842.445 ◽

2013 ◽

Vol 842 ◽

pp. 445-448

Author(s):

Wei Chao Yang ◽

Chuan He ◽

Li Min Peng

Keyword(s):

High Speed ◽

Three Dimensional ◽

Horizontal Distribution ◽

Wake Flow ◽

Railway Tunnel ◽

Long Distance ◽

Near Wake ◽

High Speed Rail ◽

Numerical Work ◽

Rail Station

This paper describes the results of numerical work to determine the flow structures of the slipstream and wake of a high speed train on platforms of underground rail station using three-dimensional compressible Euler equation. The simulations were carried out on a model of a simplified three-coach train and typical cross-section of Chinese high-speed railway tunnel. A number of issues were observed: change process of slipstreams, longitudinal and horizontal distribution characteristics of train wind. Localized velocity peaks were obtained near the nose of the train and in the near wake region. Maximum and minimum velocity values were also noticed near to the nose rear tip. These structures extended for a long distance behind the train in the far wake flow. The slipstream in platform shows the typical three-dimensional characteristics and the velocity is about 4 m/s at 6 m away from the edge of platform.

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HFTViz: Visualization for the exploration of high frequency trading data

Information Visualization ◽

10.1177/14738716211064921 ◽

2021 ◽

pp. 147387162110649

Author(s):

Javad Yaali ◽

Vincent Grégoire ◽

Thomas Hurtut

Keyword(s):

Portfolio Management ◽

High Frequency ◽

High Speed ◽

High Frequency Trading ◽

Domain Experts ◽

Risk Return ◽

Visualization Tools ◽

Liquidity Measures ◽

Trading Volumes

High Frequency Trading (HFT), mainly based on high speed infrastructure, is a significant element of the trading industry. However, trading machines generate enormous quantities of trading messages that are difficult to explore for financial researchers and traders. Visualization tools of financial data usually focus on portfolio management and the analysis of the relationships between risk and return. Beside risk-return relationship, there are other aspects that attract financial researchers like liquidity and moments of flash crashes in the market. HFT researchers can extract these aspects from HFT data since it shows every detail of the market movement. In this paper, we present HFTViz, a visualization tool designed to help financial researchers explore the HFT dataset provided by NASDAQ exchange. HFTViz provides a comprehensive dashboard aimed at facilitate HFT data exploration. HFTViz contains two sections. It first proposes an overview of the market on a specific date. After selecting desired stocks from overview visualization to investigate in detail, HFTViz also provides a detailed view of the trading messages, the trading volumes and the liquidity measures. In a case study gathering five domain experts, we illustrate the usefulness of HFTViz.

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Notch-based speed trajectory optimisation for high-speed railway automatic train operation

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/09544097211042184 ◽

2021 ◽

pp. 095440972110421

Author(s):

Minling Feng ◽

Chaoxian Wu ◽

Shaofeng Lu ◽

Yihui Wang

Keyword(s):

High Speed ◽

Applied Force ◽

Mixed Integer ◽

High Speed Railway ◽

Train Operation ◽

Train Speed ◽

Automatic Train Operation ◽

The Impact ◽

Trajectory Optimisation

Automatic train operation (ATO) systems are fast becoming one of the key components of the intelligent high-speed railway (HSR). Designing an effective optimal speed trajectory for ATO is critical to guide the high-speed train (HST) to operate with high service quality in a more energy-efficient way. In many advanced HSR systems, the traction/braking systems would provide multiple notches to satisfy the traction/braking demands. This paper modelled the applied force as a controlled variable based on the selection of notch to realise a notch-based train speed trajectory optimisation model to be solved by mixed integer linear programming (MILP). A notch selection model with flexible vertical relaxation was proposed to allow the traction/braking efforts to change dynamically along with the selected notch by introducing a series of binary variables. Two case studies were proposed in this paper where Case study 1 was conducted to investigate the impact of the dynamic notch selection on train operations, and the optimal result indicates that the applied force can be flexibly adjusted corresponding to different notches following a similar operation sequence determined by optimal train control theory. Moreover, in addition to the maximum traction/braking notches and coasting, medium notches with appropriate vertical relaxation would be applied in accordance with the specific traction/braking demands to make the model feasible. In Case study 2, a comprehensive numerical example with the parameters of CRH380AL HST demonstrates the robustness of the model to deal with the varying speed limit and gradient in a real-world scenario. The notch-based model is able to obtain a more realistic optimal strategy containing dynamic notch selection and speed trajectory with an increase (1.622%) in energy consumption by comparing the results of the proposed model and the non-notch model.

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