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491.
In recent years, China’s increased interest in environmental protection has led to a promotion of energy-efficient dual fuel (diesel/natural gas) ships in Chinese inland rivers. A natural gas as ship fuel may pose dangers of fire and explosion if a gas leak occurs. If explosions or fires occur in the engine rooms of a ship, heavy damage and losses will be incurred. In this paper, a fault tree model is presented that considers both fires and explosions in a dual fuel ship; in this model, dual fuel engine rooms are the top events. All the basic events along with the minimum cut sets are obtained through the analysis. The primary factors that affect accidents involving fires and explosions are determined by calculating the degree of structure importance of the basic events. According to these results, corresponding measures are proposed to ensure and improve the safety and reliability of Chinese inland dual fuel ships. 相似文献
492.
The dispute settlement mechanism (DSM) has long been the focus of attention because of its significant role in the institutional construction of China’s free trade agreements (FTAs). Thus, this paper is to make an analysis of the DSMs of China’s established FTAs from a legal perspective of international regime study, which leads to the finding of a co-existence mode of formal and informal DSMs in China’s FTAs. This paper also discusses the motivation and significance of such a choice. 相似文献
493.
Cam-rotor vane motor (CRVM) is one of the new continuous hydraulic servo motors with the characteristics of no pulsation of instantaneous flow rate and output torque, small volume and rotating inertia. It is one of the appropriate actuators for hydraulic servo system which has good dynamic and steady-state performance requirements. The ideal output torque of CRVM is pulseless, but the actual output torque of CRVM is pulsating. This is caused by the disturbing torque of contact components, especially the friction between vane and cam-rotor. In order to get better performance of CRVM, which means more stable output torque and smaller disturbing torque, we discuss four kinds of vane end faces (VEFs). Analytic formulae of the normal contact force and the disturbing torque caused by the vane are derived from systematical force analysis. The normal contact force and the disturbing torque vary through a period under different VEF, and the reduced oil pressure is simulated in this paper. The simulation shows that the VEF with the proper round and reduced oil pressure can significantly decrease the disturbing torque and get better servo performance. The experiment results verify the correctness of the theoretical analysis and simulation. 相似文献
494.
Transportation sector, including maritime transport, exerts significant environmental impact. Public procurement as a policy strategy instrument which applies to the purchase of transport means, construction of infrastructure and the provision logistic services in supplying the goods, services and executing of works must integrate environmental considerations in the contract award procedures. While conventional life-cycle costing (LCC) is based on four categories to be assessed e.g. investment, operation, maintenance and end-of-life disposal expenses, the environmental LCC method also takes into account the external environmental costs. The paper is focused on sustainable public procurement and environmental life-cycle costing aspects of EU 2014 Directive. Analysis is made of the real cost of procurement, the externalities and the impact of maritime transport sector on the environment. The purpose of this research is to propose the framework for assessment of integral impact on the environment which combines environmental LCC approach with TBL concept using non-monetary units for measuring externalities. The authors advocate clean and energy-efficient maritime transport ensuring effective implementation of environmental policy objectives and targets and emphasize the role of public authorities and entities in fostering the inclusion of environmental externalities in calculation of LCC. 相似文献
495.
An AdBlue dosing control strategy of the selective catalytic reduction(SCR) system is developed for a heavy-duty diesel(HDD) engine. The strategy includes a raw emission prediction model, an ammonia(NH_3)coverage prediction model, a transient heat hysteresis correction algorithm, an NH_3 leakage control model for transient operation conditions, and a feedback controller(FBC). FBC has been developed by using mathematical manipulation to change output signal of sensor based on cross-sensitivity of nitrogen oxide(NO_x) sensor to NH_3.The quantification of control parameters is based on experiments and Nyquist stability criterion. FBC is enabled in most test conditions to satisfy the stability requirements. NOxconversion(DeNO_x) efficiency of SCR system is 82.4% in European steady-state cycle(ESC) test and 80.3% in European transient cycle(ETC) test, while the leakage of NH_3 is under 10-5 volume fraction in average. 相似文献
496.
Equipment has dual nature: physical objects existing in nature, and artificial objects designed by human. The decision on the configuration and structural parameters of equipment is made by engineers based on technical-physical effects which control the behavioral parameters of the equipment. Sensors are mounted on the equipment to monitor the equipment state. Current methods for state monitoring and diagnosis mostly use mathematics and artificial intelligence technology to construct evaluation methods. This paper presents an integrated design and state maintenance method, in which graph and dual graph are used for recording design data and sensor arrangement and for mapping method from signals to substructures and connection pairs. An example of state maintenance of hydro power generating equipment is illustrated. 相似文献
497.
498.
Directionality of image plays a very important role in human visual system and it is important prior information of image. In this paper we propose a weighted directional total variation model to reconstruct image from its finite number of noisy compressive samples. A novel self-adaption, texture preservation method is designed to select the weight. Inspired by majorization-minimization scheme, we develop an efficient algorithm to seek the optimal solution of the proposed model by minimizing a sequence of quadratic surrogate penalties. The numerical examples are performed to compare its performance with four state-of-the-art algorithms. Experimental results clearly show that our method has better reconstruction accuracy on texture images than the existing scheme. 相似文献
499.
Thomas A. Hamade 《上海交通大学学报(英文版)》2018,23(1):112-121
A novel high-voltage electrostatics corona ions pre-charger apparatus and methods were invented earlier by Hamade related to treat various types of receptors such as but not limited to electret polymer, air filters, particulates, catalytic converters, bioaerosols, fluids, pollutants, virus, and bacteria. It is shown in this article that his work led to the construction of various prototype chargers, customized differently for each type of a receptor. In particular his recent development of biological matter corona charger (BMCC) prototype related to expose, treat, sanitize, and disinfect bioaerosols, virus, bacteria, and contaminated fluids and blood such as human immunodeficiency virus (HIV) - acquired immune deficiency syndrome (AIDS). It is shown in this paper that each previous investigated research contemplated ionized corona charger attendant to a charging process and the corona, imparts and provides enough treatment charges to receptors including the aforementioned receptors. Researchers often relied on adopting prior corona charger methods that do not necessarily and effectively solve the problems associated with them or utilize them for optimum treatment effect. The inventor exhaustively studied the characteristics of corona discharge, and has found that the greatest difficulty in corona discharge has to do with the maintenance of the corona, particularly when the receptor is being charged. This is due to variations in either the dielectric value between the corona electrode and a grounded base or flaws in the design as the receptor passes there between suppressing or hindering corona and its effectiveness. What is needed in-the-art is an apparatus and method to achieve maximum possible charge on a receptor, a charge order of magnitude greater than that used by other investigators. This often requires customizing each apparatus and method and does not just merely use one type of a charger to satisfy all applications. To satisfy this need, we build a low cost prototype BMCC that generates self-sustaining charge corona, eliminates many previous design flaws such as spark over, and make it ready for testing remotely or with apparatus. 相似文献
500.
In digital ship-design processes, surface modeling needs to be as accurate as possible for effectiveness in ship production
as well as numerical analysis of the performance. Traditionally, the form of a ship hull is constructed from a set of cross-sectional
data. This approach entails difficulties in the cross-sectional spacing and accuracy of the characteristic curves, such as
the stern and bow profiles, deck side line, bottom tangential line, and unconnected curves. Genetic algorithms (GAs) have
attracted increasing attention as a multimodal optimization solution for surface reconstruction that enable construction of
a single non-uniform B-spline (NUB) surface at the initial stage of ship design with constraints such as knuckles, discontinuity
conditions, and bulbous bows with high curvatures, . The first, simultaneous multi-fitting GA determines the boundary curves,
such as the stem and stern profiles, and finds the common knot values for both curves. Similarly, the same GA technique is
applied for other boundary curves at the bottom and the deck. The second GA is employed to fit the interior data points after
the boundary curves are fitted. The encoded design variables for surface construction are the locations of the vertices and
the knot values. Those variables are modified for improving the surface quality until a predefined degree of precision is
attained. In four instances of application, the GA technique developed in this research has been shown to provide good, single,
NUB surfaces with high efficiency. In the early design stage, a single NUB surface is more convenient for performance visualization
and finite-element methods. It can be readily translated into many CAD/CAM packages, which facilitate the smooth transition
of data across the different design stages. 相似文献