Regression analysis of initial stress field around faults based on fault throw by displacement discontinuity method

The back analysis of initial stress is usually based on measured stress values, but the measuring of initial stress demands substantial investment. Therefore, amounts of underground engineering have no measured initial stress data, such as tunneling engineering. Focusing on this problem, a new back analysis method which does not need measured initial stress data is developed. The fault is assumed to be caused by initial load, the displacement discontinuity method (DDM) which considered non-linear fault is adopted to establish a numerical model of the engineering site, and the multivariable regression analysis of the initial stress field around the faults is carried out based on the fault throw. The result shows that the initial stress field around the faults is disturbed significantly, stress concentration appears in the tip zone, the regressive fault throw matches the measured values well, and the regressive initial stress field is reliable.     

Applying social marginal cost pricing in rail PPPs: Present state, drawbacks and ways forward

The application of social marginal cost pricing (SMCP) in PPP's in the railway sector faces several challenges. We examine in detail the practical applicability of SMCP in railway PPPs from the perspectives of cost accounting and effectiveness of SMCP towards the allocative efficiency goal, addressing the likely drawbacks in conciliating the welfare objectives of SMCP with the objectives of project financing (cost recovery) and value for money that justify the realization of PPP's. To this end, we combine theoretical analysis with the observation of empirical results of a case study. We split the analysis per type of private service provision, which can be for service operation or infrastructure management. For infrastructure management, we recommend splitting the operator remuneration and the track access charges. For service operation, we argue that the correct decision on source of funding of the service operator should depend on the characteristics of the contract.     

Measurements of Emissions to Air from a Marine Engine Fueled by Methanol

Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for ...     

青岛董家口港城公共交通安全规划探索与实践

城市交通运行安全关乎千家万户,现已成为人们越来越关注的热点,2019年,我国发生的道路交通事故共导致14527人死亡[1],交通事故产生的损失越来越大.公共交通是城市交通的重中之重,其交通安全的社会影响极大.交通事故产生原因受到人、车、道路以及周围环境等多维度因素影响,交通安全规划研究需要围绕以上因素展开.本文以董家口港城为例,多维度探索了公交安全规划的方法,从公共交通的视角剖析了交通事故原因,提出了面向港口城市交通安全治理的综合对策,制定了综合提升方案,为青岛董家口港城交通安全提升做出了积极探索和实践.     

Oil spill risk analysis of routeing heavy ship traffic in Norwegian waters

Norwegian authorities have for a long time been concerned about the risk of oil spills outside the Norwegian coast. One of the key measures adopted has been to reduce the risk of ship accidents by imposing sailing routes for heavy ship traffic (over 5,000 gross tonnages) with high environmental risk potential farther away from part of the coast. This article is based upon two reports which conducted risk assessments of imposing such sailing routes outside the entire Norwegian coast. These routes were proposed by an expert group consisting of relevant stakeholders. Data of traffic pattern and number of sailing were collected for the year 2008 using the universal Automatic Identification System (AIS). The proposed route was compared with 2008 traffic pattern in regard to the accident frequencies and the expected oil spills per year. An accident and oil spilling simulation program called MARCS was used to simulate these results. After conducting a traffic forecast for the year 2025, the simulation was again run and the results compared with the year 2008. In total, the proposed route is expected to reduce oil spills by 590 t per year in 2008 and by 3670?t in 2025. The main reason for this substantial reduction is that the number of groundings is reduced because of the distance from the shore being increased. The reduction was particularly strong for tankers.     

From Titanic to Costa Concordia—a century of lessons not learned

The recent foundering of the Costa Concordia in January 2012 demonstrated that accidents can occur even with ships that are considered masterpieces of modern technology and despite more than 100?years of regulatory and technological progress in maritime safety. The purpose of this paper is, however, not to speculate about the concrete causes of the Costa Concordia accident, but rather to consider some human and organizational factors that were present in the Costa Concordia accident as well as in the foundering of the Titanic a century ago, and which can be found in many other maritime accidents over the years. The paper argues that these factors do not work in isolation but in combination and often together with other underlying factors. The paper critically reviews the focus of maritime accident investigations and points out that these factors do not receive sufficient attention. It is argued that the widespread confidence in the efficacy of new or improved technical regulations, that characterizes the recommendations from most maritime accident investigations, has led to a lack of awareness of complex interactions of factors and components in socio-technical systems. If maritime safety is to be sustainably improved, a systemic focus must be adopted in future accident investigations.     

A study of the effects of spatial contiguity and hierarchically structured headings in a shipboard operating and maintenance manual

The notion of operating and maintenance manuals being validated as fit for purpose is based largely on conjecture, as causal factors contributing to rule-based (procedure-based) human error at sea are under-theorised and under-researched. Human factors theories offer little in terms of framework as to the constitution of a bad rule. In this study, an original equipment manufacturer (OEM) operating and maintenance manual was assessed against two rule-based error-provoking markers identified through literature review. The contribution of the original and subsequently modified OEM operating and maintenance manuals towards both behaviour modification and rule-based error was assessed through a workshop-based study. Randomly selected seafaring participants were tasked with the responsibility of executing a typical shipboard operational procedure by referring to an original or modified version of the manual. The study supported the following hypotheses: (1) the hierarchical access structure of headings in an operating and maintenance manual supports the primary function of selection, and (2) the efficacy of inference in a procedure-based task is dependent upon the spatial contiguity of corresponding text and illustrations in an operating and maintenance manual. The findings of this study suggest that a nexus exists between the structure of operating and maintenance manuals, behaviour modification and human error. Furthermore, this study demonstrates a need for further research into specific causal factors contributing towards rule-based error in shipboard operating and maintenance tasks.     

The applicability of hydrofoils as a ship control device

Centrifugal forces are commonly created when ships turn, which may cause a ship to capsize in a critical situation. A mathematical model has been developed to optimize the stability coefficients for ship, with the aim to prevent capsizing and to increase ship maneuverability in high-speed water craft. This model can be used to develop algorithms for control system improvement. The mathematical model presented in this paper optimized the use of multipurpose hydrofoils to reduce heeling and the trimming moment, maintaining an upright ship’s position and lessening the resistance via transverse force. Conventionally, the trimming and heeling of a ship are controlled using ballast water; however, under variable sea conditions it is sometimes difficult to control a ship’s motion using ballast water. In this case, a hydrofoil would be more stable and maneuverable than a ballast tank controlled vessel. A movable hydrofoil could theoretically be adapted from moveable aerofoil technology. This study proves the merit of further investigation into this possibility.