Oriented review to potential simulator for faults modeling in diesel engine

This paper presents a literature review on most of the faults and their models that are considered on a diesel engine. Several faults that may be produced on diesel engine have been analyzed, classified, modeled, and their influences on the global system have been shown. Thus, this paper aims to prepare an important data base on diesel engine faults which may help researchers to develop precise strategies on diesel engine fault diagnosis and prognosis, and also it helps in the development of diesel engine simulators aiming to study the behavior of the diesel engine in the presence of faults. Different fault models such as analytical, empirical, degradation models which may be represented as function of time or as function of the number of cycles, data driven models such as neural network models, or simply constant are presented and analyzed. The global overall models for diesel engine integrating faults are expressed. And finally, the use of these models with the most common failure density distribution functions is proposed giving a more realistic approach to our study.     

Advantages of twin rudder system with asymmetric wing section aside a propeller

This study presents a new twin rudder system with asymmetric wing section, aside a propeller, as a new category energy saving device (ESD) for ships. The energy saving principle of the new ESD, which is called “Gate rudder”, is described and its applicability on a large bulk carrier is explored using experimental and numerical methods. The study makes emphasis on the cost-effectiveness of the proposed ESD and presents a potential energy saving up to 7–8 % with the new device as well as an attractive return investment in 0.37–0.9 year. These estimations are based on the conventional powering methods, whereas the accuracy of the ESD design method is confirmed by model test measurements.     

基于PLC的船舶空气源热泵供热水控制系统研发

为了极大限度节省船舶热水站能耗,研制出一套空气源热泵热水控制系统及PLC与变频器构成恒压供热水系统,并通过触摸屏对系统进行参数设置和实时监控,可保证昼夜不间断恒压供水,提高了船舶热水站的可靠性和经济性。     

Application of digital image correlation method to in-situ dynamic strain measurement

Application of digital image correlation (DIC) method to determination of in-situ dynamic strain is presented in this study. Firstly, an integrative software is programmed based on the DIC algorithms and point-wise least-squares fitting technique. Then, simulated speckle images are generated to study the computational accuracy of this software. The experimental setup and procedures for measuring in-situ dynamic strain through both DIC and strain gauge are proposed. The DIC results are close to those measured by strain gauge. This fact reveals that DIC is a practical and effective tool for in-situ dynamic strain measurement. Finally, the full-field in-situ dynamic strain of another specimen is measured by DIC, and the overall distribution of the strain in the measurement area is clearly shown.     

大倾角中厚煤层软弱顶底板柔性护巷技术

在大倾角中厚煤层沿空留巷中,以往的支护方式难以满足大倾角中厚煤层巷道特殊的围岩结构稳定的需要,同时无法适应工作面内矸石垮落造成留巷困难。文章针对这一难题,首次提出并采用了"柔性护巷"技术,通过利用巷道上帮形成的由垮落矸石堆积在特制钢筋网上的"包护带",允许巷道顶板有一定的下沉量,从而使矸石充分为巷道顶板组合岩梁结构提供支撑力。在总结其施工工艺的基础上,通过现场试验,研究了巷道矿压显现规律、顶板移动规律、矸石垮落堆积规律和钢筋网变形规律;实验结果表明,在利用锚、网、索、支柱联合支护的基础上,应用"柔性护巷"技术能有效地解决大倾角中厚煤层沿空留巷技术难题。     

Characteristics analysis for travel behavior of transportation hub passengers using mobile phone data

The travel behavior of passengers from the transportation hub within the city area is critical for travel demand analysis, security monitoring, and supporting traffic facilities designing. However, the traditional methods used to study the travel behavior of the passengers inside the city are time and labor consuming. The records of the cellular communication provide a potential huge data source for this study to follow the movement of passengers. This study focuses on the passengers’ travel behavior of the Hongqiao transportation hub in Shanghai, China, utilizing the mobile phone data. First, a systematic and novel method is presented to extract the trip information from the mobile phone data. Several key travel characteristics of passengers, including passengers traveling inside the city and between cities, are analyzed and compared. The results show that the proposed method is effective to obtain the travel trajectories of mobile phone users. Besides, the travel behavior of incity passengers and external passengers are quite different. Then, the correlation analysis of the passengers’ travel trajectories is provided to research the availability of the comprehensive area. Moreover, the results of the correlation analysis further indicate that the comprehensive area of the Hongqiao hub plays a relatively important role in passengers’ daily travel.

     

CT reconstruction with priori MRI images through multi-group datasets expansion

Computed tomography (CT) reconstruction with a well-registered priori magnetic resonance imaging (MRI) image can improve reconstruction results with low-dose CT, because well-registered CT and MRI images have similar structures. However, in clinical settings, the CT image of patients does not always match the priori MRI image because of breathing and movement of patients during CT scanning. To improve the image quality in this case, multi-group datasets expansion is proposed in this paper. In our method, multi-group CT-MRI datasets are formed by expanding CT-MRI datasets. These expanded datasets can also be used by most existing CT-MRI algorithms and improve the reconstructed image quality when the CT image of a patient is not registered with the priori MRI image. In the experiments, we evaluate the performance of the algorithm by using multi-group CT-MRI datasets in several unregistered situations. Experiments show that when the CT and priori MRI images are not registered, the reconstruction results of using multi-group dataset expansion are better than those obtained without using the expansion.     

Seafarers’ perceptions of competency in risk assessment and management: an empirical study

Past analysis of accident investigations suggest an absence of or inadequate practices of risk assessment and management on board vessels. Although the International Management Code for the Safe Operation of Ships and for Pollution Prevention (ISM Code) requires that the risk management process must not only be correctly formulated and implemented but also be periodically evaluated in order to verify that these objectives are attained, the correct and effective implementation and application of the process cannot be achieved without active involvement of competent seafarers on board. Due to the limited investigation of seafarers’ competencies in risk management, the reasons for the inadequacies in the process that are leading to accidents were not evident. Hence, using a survey, this paper conducted a pilot study investigating seafarers’ perceptions of competency in the various components of the risk management process conducted on board vessels. The findings of this paper suggest an overall satisfaction with the risk assessment process. However, there is certainly room for improvement as far as seafarers’ performance is concerned. The findings of this paper provided valuable insights into the current training regimes in the area of risk assessment and management paving the way towards enhanced safety procedures on board vessels.     

浅谈填砂路基施工关键技术及其环保效果

文章结合南昌市某实际工程,探讨了高速公路填砂路段施工过程的关键技术,重点从施工方案的确定、原地面的处理、排水层的施工,以及填砂施工流程等方面进行分析,以供参考。     

Automatic outer surface extraction of femoral head in CT images

Computer-aided hip surgery planning and implant design applications require accurate segmentation of femoral head and proximal acetabulum. An accurate outer surface extraction of femoral head using marching cubes algorithm remains challenging due to deformed shapes and extremely narrow inter-bone regions. In this paper, we present an automatic and fast approach for segmentation of femoral head and proximal acetabulum which leads to accurate and compact representation of femoral head using marching cubes algorithm. At first, valley-emphasized images are constructed from original images so that valleys stand out in high relief. Otsu’s multiple thresholding technique is applied to seperate the images into bone and non-bone classes. Region growing method and threedimensional (3D) morphological operations are performed to fill holes in the bone. In the reclassification process, the bone regions are further segmented, and the boundaries of the bone regions are further refined based on Bayes decision rule. Finally, marching cubes algorithm is applied to reconstruct a 3D model and extract the outer surface of femoral head and proximal acetabulum. Experimental results show that this method is an accurate segmentation technique for femoral head and proximal acetabulum and it can be applied as a tool in medical practice.