scholarly journals Design theories and maintenance technologies of slab tracks for high-speed railways in China: a review

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Juanjuan Ren ◽  
Shijie Deng ◽  
Kaiyao Zhang ◽  
Wei Du ◽  
Qinghong Wu
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Research Trend ◽  
Future Research ◽  
Stable Operation ◽  
High Speed Railway ◽  
Slab Track ◽  
Design Theories ◽  
Future Direction

Abstract The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways. In order to provide a solid theoretical basis and technical reference for the advancement of high-speed railway quality, this paper comprehensively discusses design theories of slab track structures, service performance evolution and maintenance technologies, and reviews the innovation happening in the industry. On top of that, the damage evolution, fatigue features and durability of slab tracks, which are highly relevant to serviceability, are summarized, and the future research trend of slab track service behaviours is pointed out. In addition, this paper summarizes the rules of establishing standards for damage maintenance, typical solutions for repairing damage and methods of evaluating the maintenance outcomes that combine field tests and numerical simulations. It also envisions a future direction where advanced testing technologies would assist the evaluation of maintenance effects.

Ketamine Treatment in Depression: A Systematic Review of Clinical Characteristics Predicting Symptom Improvement

2020 ◽  
Vol 20 (15) ◽  
pp. 1398-1414 ◽  
Author(s):  
Darby J.E. Lowe ◽  
Daniel J. Müller ◽  
Tony P. George
Keyword(s):  
Clinical Features ◽  
Clinical Characteristics ◽  
Bipolar Depression ◽  
Antidepressant Effect ◽  
Future Research ◽  
Symptom Improvement ◽  
Randomized Controlled ◽  
Treatment Of Depression ◽  
Future Direction

Ketamine has been shown to be efficacious for the treatment of depression, specifically among individuals who do not respond to first-line treatments. There is still, however, a lack of clarity surrounding the clinical features and response periods across samples that respond to ketamine. This paper systematically reviews published randomized controlled trials that investigate ketamine as an antidepressant intervention in both unipolar and bipolar depression to determine the specific clinical features of the samples across different efficacy periods. Moreover, similarities and differences in clinical characteristics associated with acute versus longer-term drug response are discussed. Similarities across all samples suggest that the population that responds to ketamine’s antidepressant effect has experienced chronic, long-term depression, approaching ketamine treatment as a “last resort”. Moreover, differences between these groups suggest future research to investigate the potential of stronger efficacy towards depression in the context of bipolar disorder compared to major depression, and in participants who undergo antidepressant washout before ketamine administration. From these findings, suggestions for the future direction of ketamine research for depression are formed.

How to balance interfirm relationships? A case from high-speed railway industry

2020 ◽  
Vol 35 (11) ◽  
pp. 1785-1799 ◽  
Author(s):  
Na Zhang ◽  
Xiaopeng Deng ◽  
Bon-Gang Hwang ◽  
Yanliang Niu
Keyword(s):  
High Speed ◽  
Superior Performance ◽  
Interfirm Relationships ◽  
High Speed Railway ◽  
Content Type ◽  
Railway Industry ◽  
Interfirm Cooperation ◽  
Relationship Structures ◽  
Interfirm Competition

Purpose Balancing interfirm relationships is important for firms’ long-term superior performance. However, prior studies mainly focus on interfirm competition or interfirm cooperation separately, ignoring the balance of interfirm relationships. To bridge this gap in knowledge, this study aims to develop a framework to evaluate the balance of interfirm competition and interfirm cooperation and propose strategies to optimize a firm’s interfirm relationships. Design/methodology/approach After an in-depth literature review, a framework was developed for evaluating and optimizing the interfirm relationships. Taking the high-speed railway industry as an example, the proposed framework was implemented. Findings The results of the case confirm that the balancing of interfirm relationships can lead to more superior firm performance. Also, rather than mutual suppression, the interfirm competition and interfirm cooperation present a roughly positive relationship. Originality/value This study would contribute to the existing knowledge body by developing a framework for balancing interfirm relationships. Also, this study can aid practitioners in evaluating and optimizing their interfirm relationship structures.

scholarly journals INDUSTRI 4.0: TELAAH KLASIFIKASI ASPEK DAN ARAH PERKEMBANGAN RISET

2018 ◽  
Vol 13 (1) ◽  
pp. 17 ◽  
Author(s):  
Hoedi Prasetyo ◽  
Wahyudi Sutopo
Keyword(s):  
Literature Review ◽  
Research Methods ◽  
Industry 4.0 ◽  
Manufacturing Industry ◽  
Industrial Revolution ◽  
Research Direction ◽  
Research Trend ◽  
Future Research ◽  
Upward Trend ◽  
Future Direction

AbstrakIstilah Industri 4.0 lahir dari ide tentang revolusi industri keempat. Keberadaannya menawarkan banyak potensi manfaat. Guna mewujudkan Industri 4.0, diperlukan keterlibatan akademisi dalam bentuk riset. Artikel ini bertujuan untuk menelaah aspek dan arah perkembangan riset terkait Industri 4.0. Pendekatan yang digunakan adalah studi terhadap beragam definisi dan model kerangka Industri 4.0 serta pemetaan dan analisis terhadap sejumlah publikasi. Beberapa publikasi bertema Industri 4.0 dipilah menurut metode penelitian, aspek kajian dan bidang industri. Hasil studi menunjukkan Industri 4.0 memiliki empat belas aspek. Ditinjau dari metode penelitian, sebagian besar riset dilakukan melalui metode deskriptif dan konseptual. Ditinjau dari aspeknya, aspek bisnis dan teknologi menjadi fokus riset para peneliti. Ditinjau dari bidang industri penerapannya, sebagian besar riset dilakukan di bidang manufaktur. Ditinjau dari jumlahnya, riset terkait Industri 4.0 mengalami tren kenaikan yang signifikan. Artikel ini diharapkan dapat memberi gambaran mengenai apa itu Industri 4.0, perkembangan dan potensi riset yang ada di dalamnya. AbstractIndustry 4.0: Study of Aspects Classification and Future Research Direction. The term Industrial 4.0 refers to the idea about fourth industrial revolution. In order to realize Industry 4.0, academic involvement is required in the form of research. This article aims to define the aspects and future direction of research related to Industry 4.0. Literature review of various definition and concept models of Industry 4.0. was conducted to acquire the aspects. Mapping and analysis of several publications were conducted to determine the future direction of research. Publications were sorted according to research methods, aspects and type of industry. The result shows that Industry 4.0 has fourteen aspects. Based on research methods, most of the research is done through descriptive and conceptual methods. Business and technology aspects become the focus of the researchers and most of the research is done in manufacturing industry. Based on quantities, Industrial 4.0 research has experienced a significant upward trend. This article is expected to illustrate the concept, future development and research trend of Industry 4.0.Keywords: Industry 4.0; Literature Review; Research Trend

scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

scholarly journals Evolution of Rheological Behaviors of Styrene-Butadiene-Styrene/Crumb Rubber Composite Modified Bitumen after Different Long-Term Aging Processes

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2345 ◽  
Author(s):  
Yangsheng Ye ◽  
Gang Xu ◽  
Liangwei Lou ◽  
Xianhua Chen ◽  
Degou Cai ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Crumb Rubber ◽  
Modified Bitumen ◽  
High Speed Railway ◽  
Modified Asphalt ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

In this study, a new type of composite modified bitumen was developed by blending styrene-butadiene-styrene (SBS) and crumb rubber (CR) with a chemical method to satisfy the durability requirements of waterproofing material in the waterproofing layer of high-speed railway subgrade. A pressure-aging-vessel test for 20, 40 and 80 h were conducted to obtain bitumen samples in different long-term aging conditions. Multiple stress creep recovery (MSCR) tests, linear amplitude scanning tests and bending beam rheometer tests were conducted on three kinds of asphalt binders (SBS modified asphalt, CR modified asphalt and SBS/CR composite modified asphalt) after different long-term aging processes, including high temperature permanent deformation performance, resistance to low temperature thermal and fatigue crack. Meanwhile, aging sensitivities were compared by different rheological indices. Results showed that SBS/CR composite modified asphalt possessed the best properties before and after aging. The elastic property of CR in SBS/CR composite modified asphalt improved the ability to resist low temperature thermal and fatigue cracks at a range of low and middle temperatures. Simultaneously, the copolymer network of SBS and CR significantly improved the elastic response of the asphalt SBS/CR modified asphalt at a range of high temperatures. Furthermore, all test results indicated that the SBS/CR modified asphalt possesses the outstanding ability to anti-aging. SBS/CR is an ideal kind of asphalt to satisfy the demand of 60 years of service life in the subgrade of high speed railway.

Design and Construction Technologies

2010 ◽  
Author(s):  
Cailan Wu ◽  
Weixiao Cui ◽  
Chengzhi Zhang ◽  
Huaijian Li ◽  
Hongliang Yan
Keyword(s):  
High Speed ◽  
Actual Situation ◽  
Technical Standard ◽  
High Speed Railway ◽  
Deformation Control ◽  
Slab Track ◽  
Railway Construction ◽  
Scheme Optimization ◽  
Key Technologies ◽  
Design And Construction

Combining with the actual situation of China’s railway construction, this paper introduces the key technologies of design and construction of high-speed railway, such as the scheme optimization of subgrade, bridge and tunnel, technical standard, deformation control, advance geology forecast and settlement observation, etc. It also discusses the design and construction problems on the slab layout and interface of CRTS II slab track on bridge section, switch area, subgrade area and the transition with different track structures.

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