scholarly journals Historical review of lighthouse design under wind load: the Ile Vierge lighthouse

2019 ◽  
Vol 377 (2155) ◽  
pp. 20190167 ◽  
Author(s):  
Nathalie Domede ◽  
Luisa Pena ◽  
Nicolas Fady
Keyword(s):  
Nineteenth Century ◽  
Design Method ◽  
Historical Review ◽  
Wind Load ◽  
Scientific Journals ◽  
Theme Issue ◽  
Calculation Results ◽  
European Standards ◽  
The Stability ◽  
The Uk

The purpose of the study presented here is to describe the design method used by engineers in the nineteenth and early twentieth centuries to size lighthouse structures and to compare them with current European standards. The historical information presented here is derived from two sources in particular: the archives of the Ile Vierge lighthouse, which was built at the northern tip of Brittany between 1897 and 1902, and the scientific journals, books and courses available at that time. Firstly, the article describes the structure of the Ile Vierge lighthouse, which is the tallest stone lighthouse in Europe. The wind load acting on lighthouses and chimneys was formulated in France by L. Fresnel in 1825. Fresnel's work is compared to W. J. M. Rankine's theory used in the UK. The safety coefficients applied with respect to the stability of the towers in France and the UK in the nineteenth-century are compared. On the occasion of the construction of the Ile Vierge lighthouse, the masonry strength under wind loads led to a discussion among engineers of the French lighthouse authorities. They also worried about the risk of excessive oscillations of the towers, which could cause a dysfunction of the lamp. Thirdly, the standard wind action defined in Eurocode 1 is applied to the Ile Vierge lighthouse. Calculation results are given. A comparative analysis of the ancient and modern methods is presented. Overall, this historical research shows that the designers of lighthouses in the nineteenth-century had the same objectives as today: to build strong, durable structures in which deformations under loads are compatible with serviceability. This article is part of the theme issue ‘Environmental loading of heritage structures’.

Slope Stability Analysis under the Condition of Seepage

2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin
Keyword(s):  
Finite Element Method ◽  
Shear Strength ◽  
Slope Stability ◽  
Negative Impact ◽  
Strength Reduction ◽  
Soil Slope ◽  
Failure State ◽  
Calculation Results ◽  
The Stability ◽  
Shear Strength Reduction

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.

scholarly journals A history of high-power laser research and development in the United Kingdom

2021 ◽  
Vol 9 ◽  
Author(s):  
Colin N. Danson ◽  
Malcolm White ◽  
John R. M. Barr ◽  
Thomas Bett ◽  
Peter Blyth ◽  
...  
Keyword(s):  
Research And Development ◽  
High Power ◽  
Laser Action ◽  
Historical Review ◽  
High Power Laser ◽  
Power Laser ◽  
The United Kingdom ◽  
History Of ◽  
The Uk ◽  
Made In

Abstract The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

scholarly journals Suboptimal Disturbance Observer Design Using All Stabilizing Q Filter for Precise Tracking Control

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1434 ◽  
Author(s):  
Wonhee Kim ◽  
Sangmin Suh
Keyword(s):  
Design Method ◽  
Industrial Applications ◽  
Point Of View ◽  
Observer Design ◽  
Linear Matrix ◽  
External Disturbances ◽  
Closed Loop Systems ◽  
Control Target ◽  
The Stability ◽  
Unified Index

For several decades, disturbance observers (DOs) have been widely utilized to enhance tracking performance by reducing external disturbances in different industrial applications. However, although a DO is a verified control structure, a conventional DO does not guarantee stability. This paper proposes a stability-guaranteed design method, while maintaining the DO structure. The proposed design method uses a linear matrix inequality (LMI)-based H∞ control because the LMI-based control guarantees the stability of closed loop systems. However, applying the DO design to the LMI framework is not trivial because there are two control targets, whereas the standard LMI stabilizes a single control target. In this study, the problem is first resolved by building a single fictitious model because the two models are serial and can be considered as a single model from the Q-filter point of view. Using the proposed design framework, all-stabilizing Q filters are calculated. In addition, for the stability and robustness of the DO, two metrics are proposed to quantify the stability and robustness and combined into a single unified index to satisfy both metrics. Based on an application example, it is verified that the proposed method is effective, with a performance improvement of 10.8%.

scholarly journals Synchrotron science in the UK: NINA, the SRS and Diamond

2019 ◽  
Vol 377 (2147) ◽  
pp. 20190147 ◽  
Author(s):  
S. Samar Hasnain ◽  
C. Richard A. Catlow
Keyword(s):  
Theme Issue ◽  
Synchrotron Science ◽  
The Uk

The development of synchrotron science over the last 50 years is reviewed from the perspective of the authors' own scientific programmes. This article is part of the theme issue ‘Fifty years of synchrotron science: achievements and opportunities’.

scholarly journals Actuator Saturated Fuzzy Controller Design for Interval Type-2 Takagi-Sugeno Fuzzy Models with Multiplicative Noises

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 823
Author(s):  
Wen-Jer Chang ◽  
Yu-Wei Lin ◽  
Yann-Horng Lin ◽  
Chin-Lin Pen ◽  
Ming-Hsuan Tsai
Keyword(s):  
Nonlinear Systems ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Actuator Saturation ◽  
Design Method ◽  
Fuzzy Model ◽  
The Stability ◽  
Interval Type ◽  
Takagi Sugeno

In many practical systems, stochastic behaviors usually occur and need to be considered in the controller design. To ensure the system performance under the effect of stochastic behaviors, the controller may become bigger even beyond the capacity of practical applications. Therefore, the actuator saturation problem also must be considered in the controller design. The type-2 Takagi-Sugeno (T-S) fuzzy model can describe the parameter uncertainties more completely than the type-1 T-S fuzzy model for a class of nonlinear systems. A fuzzy controller design method is proposed in this paper based on the Interval Type-2 (IT2) T-S fuzzy model for stochastic nonlinear systems subject to actuator saturation. The stability analysis and some corresponding sufficient conditions for the IT2 T-S fuzzy model are developed using Lyapunov theory. Via transferring the stability and control problem into Linear Matrix Inequality (LMI) problem, the proposed fuzzy control problem can be solved by the convex optimization algorithm. Finally, a nonlinear ship steering system is considered in the simulations to verify the feasibility and efficiency of the proposed fuzzy controller design method.

The UK and EMU: Choosing the Regime

2002 ◽  
Vol 180 ◽  
pp. 54-71 ◽  
Author(s):  
Ray Barrell
Keyword(s):  
Euro Area ◽  
Policy Framework ◽  
Medium Term ◽  
Fiscal Regimes ◽  
The Stability ◽  
The Uk

The UK has to make a decision on membership of EMU in the next two years. The monetary and fiscal regimes in the Euro Area and in the UK do not differ greatly. However, we argue that membership of EMU will increase the stability of the economy and the credibility of the policy framework, and hence will enhance the prospects for growth and higher incomes and employment. There appear to be no major problems associated with joining EMU at around 1.50 euros to the pound, although there are risks to the UK if the euro appreciates against the dollar after we have entered. However, the costs associated with this risk have to be offset against the probability of the significant output gains that could come from EMU membership in the medium term.

scholarly journals Numerical Analyses on the Stability of a Deep Coalmine Roadway Passing through a Fault Zone: A Case Study of the Gugui Coalfield in China

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2114
Author(s):  
Yongshui Kang ◽  
Congcong Hou ◽  
Jingyi Liu ◽  
Zhi Geng ◽  
Jianben Chen ◽  
...  
Keyword(s):  
Fault Zone ◽  
Distinct Element ◽  
Three Dimensional ◽  
Tectonic Stress ◽  
Three Dimensional Model ◽  
Support Strategy ◽  
Failure Theory ◽  
Calculation Results ◽  
Pass Through ◽  
The Stability

Massive deformation often occurs when deep coalmine roadways pass through a fault zone due to the poor integrity of rock mass and high tectonic stress. To study deformation characteristics of the surrounding rock in the fault zone of a coalmine, a roadway passing through the FD1041 fault zone in China’s Gugui coalfield was investigated in this research. The geo-stress characteristics of this fault zone were analyzed based on the Mohr failure theory. Furthermore, a three-dimensional model for the experimental roadway in the FD1041 fault zone was built and calculated by a numerical program based on the distinct element method. Stability conditions of the roadway, using several types of support methods, were calculated and compared. Calculation results indicated that pre-grouting provides favorable conditions for the stability of a roadway in a fault zone. Finally, an optimized support strategy was proposed and implemented in the experimental roadway. Monitored results demonstrated that the optimized support strategy is appropriate for this fault zone.

Improving lives? Child poverty and social exclusion

2017 ◽  
Author(s):  
Gill Main ◽  
Jonathan Bradshaw
Keyword(s):  
Social Exclusion ◽  
Child Poverty ◽  
Policy Context ◽  
The Stability ◽  
The Uk ◽  
Over Time

This chapter details findings on child poverty and social exclusion from the 2012 UK Poverty and Social Exclusion Survey (PSE2012).It details the turbulent policy context in relation to child poverty in the years between the PSE1999 and PSE2012.It details the stability in perceptions of child necessities over time, and adult perspectives on children’s needs in 2012.The use of adult respondents in research on child poverty, and the implications of this in relation to how data can be interpreted, are detailed – and we recommend the inclusion of children in future similar studies.Findings indicate disturbingly high levels of child poverty in the UK, within a policy context which is likely to exacerbate this even further.Contrary to policy and popular rhetoric, we find no support for the idea that parental behaviours rather than ‘genuine’ poverty are the cause of children going without.Rather, parents are making substantial and personally detrimental sacrifices to ensure that their children are provided for.

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