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1.
Containership stowage plans are a pivotal teaches in the system of container transportation.With the increasing containers shipping,planning containership stowage has become more and more complicated.So intelligent stowage planning for containerships is of great significance.An effective stowage plan may improve efficiency of transportation system.First,the progress of containership stowage plan at home and abroad is reviewed,including the latest developments,such as the application of various optimization methods and computer techniques to the problem.Then,the complexities of the problem are discussed and areas where investigations are still needed are pointed out.This will provide a reference for further research on the subject.  相似文献   

2.
Containership stowage plans are a pivotal teaches in the system of container transportation. With the increasing containers shipping, planning containership stowage has become more and more complicated. So intelligent stowage planning for containerships is of great significance. An effective stowage plan may improve efficiency of transportation system. First, the progress of containership stowage plan at home and abroad is reviewed, including the latest developments, such as the application of various optimization methods and computer techniques to the problem. Then, the complexities of the problem are discussed and areas where investigations are still needed are pointed out. This will provide a reference for further research on the subject.  相似文献   

3.
In a general case, container ship serves many different ports on each voyage. A stowage planning for container ship made at one port must take account of the influence on subsequent ports. So the complexity of stowage planning problem increases due to its multi-ports nature. This problem is NP-hard problem. In order to reduce the computational complexity, the problem is decomposed into two sub-problems in this paper. First, container ship stowage problem (CSSP) is regarded as “packing problem”, ship-bays on the board of vessel are regarded as bins, the number of slots at each bay are taken as capacities of bins, and containers with different characteristics (homogeneous containers group) are treated as items packed. At this stage, there are two objective functions, one is to minimize the number of bays packed by containers and the other is to minimize the number of overstows. Secondly, containers assigned to each bays at first stage are allocate to special slot, the objective functions are to minimize the metacentric height, heel and overstows. The taboo search heuristics algorithm are used to solve the subproblem. The main focus of this paper is on the first subproblem. A case certifies the feasibility of the model and algorithm.  相似文献   

4.
More and more low - level radioactive waste is carried by sea, rail and highways. These materials are generated by public uilities, industries, universities and hospitals throughout the world, The waste is transported to available low - level waste disposal sites, primarily by ships in containers designed for transportation of low - level waste. Carriers.  相似文献   

5.
The creation of geometric model of a ship to determine the characteristics of hydrostatic and hydrodynamic, and also for structural design and equipments arrangement are so important in the ship design process. Planning tunnel high speed craft is one of the crafts in which, achievement to their top speed is more important. These crafts with the use of tunnel have the aero-hydrodynamics properties to diminish the resistance, good sea-keeping behavior, reduce slamming and avoid porpoising. Because of the existence of the tunnel, the hull form generation of these crafts is more complex and difficult. In this paper, it has attempted to provide a method based on geometry creation guidelines and with an entry of the least control and hull form adjustment parameters, to generate automatically the hull form of planning tunnel craft. At first, the equations of mathematical model are described and subsequent, three different models generated based on present method are compared and analyzed. Obviously, the generated model has more application in the early stages of design.  相似文献   

6.
Because ring-stiffened cylindrical shell structures have many merits, they are widely used in many areas. However, as the strength of steel increase continuously, ensuring of the structure stability is becoming more and more important. Therefore, it is necessary to carry on a more particular analysis. Based on the understanding and analysis of the characteristics of stability for a ring-stiffened cylindrical shell under uniform external pressure and under external single pressure, the characteristics under different cross uniform external pressures are analyzed, and the regularity of it is also gotten. The curve of stability given various geometrical parameters under different cross uniform external pressures is protracted by the analysis of the theory. The conclusion not only improves the theory structural mechanics, it also was important effects on engineering calculation and design.  相似文献   

7.
In this paper, towing tank experiments are conducted to study the behavior of flow on a model of the underwater vehicle with various shapes of bows, i.e. tango and standard bows in free surface motion tests. The total resistances for different Froude numbers are considered experimentally. The towing tank is equipped with a trolley that can operate in through 0.05–6 m/s speed with ±0.02 m/s accuracy. Furthermore, the study is done on hydrodynamic coefficients i.e. total, residual and friction resistance coefficients, and the results are compared. Finally, the study on flow of wave fields around bows is done and wave filed around two bows are compared. The Froude number interval is between 0.099 and 0.349. Blockage fraction for the model is fixed to 0.005 3. The results showed that the residual resistance of the standard bow in 0.19 to 0.3 Froude number is more than the tango bow in surface motion which causes more total resistance for the submarine. Finally, details of wave generated by the bow are depicted and the effects of flow pattern on resistance drag are discussed.  相似文献   

8.
As we know,Gatehouse (Gate-In /Gate-Out) business is one of the most important sections in the operation of container terminal(CT).On one hand,Gate-In is the first checkpoint for all export container cargoes to CTs,where we should make clear the related responsibilities of container cargoes between shippers and CTs.On the other hand,Gate-Out is the last checkpoint for all import cargoes from CTs,where the relevant liabilities of container cargoes should be distinguished by CTs and consignees,too.The CT where I work now is in Europe and ourlabor costs are much higher than those in China.In this case,in January,2010,we began to study and designanautomatic gatehouse system(AGS) in order to lower relevant costs by accelerating the passage of containers through Gate-In and Gate-Out and reducing the number of container inspectorsas well.  相似文献   

9.
Container vessels navigate among the world's ports,frequently passing through narrow and congested waters.Due to the many layers of containers on a container vessel's decks,it is difficult for the crew to be aware of all fishing vessels and other obstacles in a container vessel's radar observation blind zone.This greatly increases the risk of collisions and other accidents.Given such great challenges to safe navigation and safety management with container vessels,their security risks are severe.An effective visual monitoring system can improve the safety of the water area surrounding container vessel by eliminating a vessel's observation blind zone,providing an effective safety measure for vessels navigating fishing zones and other troublesome areas.The system has other functions,such as accident recording,ship security,and monitoring of loading and unloading operations,thus ensuring the ship operates safely.Six months'trial operation showed that the system facilitates safe navigation of container vessels.  相似文献   

10.
Eco-environment protection was given an unprecedented emphasis at the 18th National People's Congress meeting.At the same time,with the continuous increase of fuel price and the introduction of stricter emission control regulations as well as shipping industry's focus on environmental protection,application of new energy on ships has attracted more and more attention.Investment from various parties is increasing,and some scientific research projects and real vessels that are relatively mature have emerged.  相似文献   

11.
With the rapid development of China's foreign trade, the coastal and inland waterway transport has been increased rapidly. The potential market for marine engines is more and more obvious. The measurement of the engine temperature and strain becomes very important. The fluorescence fiber sensors are broadly used to measure temperature, concentration, and pH value, etc. The fluorescence sensing systems are based on different principles, namely fluorescence intensity, fluorescence intensity ratio, and fluorescence lifetime. The fluorescence lifetime is an effective parameter for sensing purpose, because it is independent of the intensity of the pumping source and does not need expensive narrow-band filters. An experiment system has been established, in which some samples were produced to measure the fluorescence lifetime and temperature characteristics and the relationship of the strain and temperature versus the fluorescence lifetime was achieved at the same time. The experiment result was fitted and analyzed. The test results show that the fluorescence lifetime decreases with the increasing of temperature. The change of fluorescence lifetime with the strain is inconspicuous comparing to that with the temperature.  相似文献   

12.
In recent years, as the composite laminated plates are widely used in engineering practice such as aerospace, marine and building engineering, the vibration problem of the composite laminated plates is becoming more and more important. Frequency, especially the fundamental frequency, has been considered as an important factor in vibration problem. In this paper, a calculation method of the fundamental frequency of arbitrary laminated plates under various boundary conditions is proposed. The vibration differential equation of the laminated plates is established at the beginning of this paper and the frequency formulae of specialty orthotropic laminated plates under various boundary conditions and antisymmetric angle-ply laminated plates with simply-supported edges are investigated. They are proved to be correct. Simple algorithm of the fundamental frequency for multilayer antisymmetric and arbitrary laminated plates under various boundary conditions is studied by a series of typical examples. From the perspective of coupling, when the number of laminated plates layers N 8–10, some coupling influence on the fundamental frequency can be neglected. It is reasonable to use specialty orthotropic laminated plates with the same thickness but less layers to calculate the corresponding fundamental frequency of laminated plates. Several examples are conducted to prove correctness of this conclusion. At the end of this paper, the influence of the selected number of layers of specialty orthotropic laminates on the fundamental frequency is investigated. The accuracy and complexity are determined by the number of layers. It is necessary to use proper number of layers of special orthotropic laminates with the same thickness to simulate the fundamental frequency in different boundary conditions.  相似文献   

13.
Shipping News     
Cargo volume in Pearl River Delta/HK trade going up Inland tranship goods transported between HK and the Pearl River Delta region in 1995 was 28.7m tons,accounting for 18% of the total throughput of HK. The container cargo shipped by lighter from the ports of the Pearl River Delta to HK in 1995 was 1.3m TEUs, 44% up from the year ealier. While over the first four months of this year ,the container tranship goods increased by 35% over the last same period. Now the ports of the Delta are planning to upgrade some facilities to meet the need for the growing containers.  相似文献   

14.
水下等离子体声源聚焦性能仿真及误差分析(英文)   总被引:2,自引:0,他引:2  
Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves. The sound source’s components and focusing mechanism were all analyzed. A model was built in 3D Max and wave strength was measured on the simulation platform. Error analysis was fully integrated into the model so that effects on sound focusing performance of processing-errors and installation-errors could be studied. Based on what was practical, ways to limit the errors were proposed. The results of the error analysis should guide the design, machining, placement, debugging and application of underwater plasma sound sources.  相似文献   

15.
The vibration isolation performances of typical hull structure with viscoelastic interlayer are analyzed according to wave theory,and the influences of interlayer Young’s modulus and length on the vibration reduction are discussed.The theoretical analysis shows that combination of polyurethane interlayer with blocking mass can enhance the vibration isolation performance and expand isolation frequency band.In order to verify the effectiveness of polyurethane interlayer,the model test of power cabin’s vibration is carried out.The test data shows that the reduction of 20–1 000 Hz variation acoustic level at hull shell is more than 5 dB.  相似文献   

16.
With the fast improvement of the technology of refrigeration in reefer containers (hereinafter referred to as 'reefer' or 'reefers'),the scope of containerizable reefer cargos is expanded continuously in the past years,from the fish that should be frozen at minus 60 degrees Celsius to the flower bulbs at 30 degrees Celsius and from the temperature-sensitive goods whose deviation should be less than 1 degree Celsius to the fresh fruits and vegetables controlled by humidityventilation adjustment system.Being an important node in the logistics chain,the container terminal (hereinafter referred to as ‘CT') should pay more attention to these state-of-the-art techniques and adopt the accordingly suitable technology to optimize its reefer monitoring business in order to provide the highly cost-effective services to ship owners (or their agents) and shippers / consignees (or their brokers).  相似文献   

17.
An optimized methodology to design a more robust torpedo shell is proposed. The method has taken into account reliability requirements and controllable and uncontrollable factors such as geometry, load, material properties, manufacturing processes, installation, etc. as well as human and environmental factors. The result is a more realistic shell design. Our reliability optimization design model was developed based on sensitivity analysis. Details of the design model are given in this paper. An example of a torpedo shell design based on this model is given and demonstrates that the method produces designs that are more effective and reliable than traditional torpedo shell designs. This method can be used for other torpedo system designs.  相似文献   

18.
There are many filtering methods that can be used for the initial alignment of an integrated inertial navigation system. This paper discussed the use of GPS, but focused on two kinds of filters for the initial alignment of an integrated strapdown inertial navigation system (SINS). One method is based on the Kalman filter (KF), and the other is based on the robust filter. Simulation results showed that the filter provides a quick transient response and a little more accurate estimate than KF, given substantial process noise or unknown noise statistics. So the robust filter is an effective and useful method for initial alignment of SINS. This research should make the use of SINS more popular, and is also a step for further research.  相似文献   

19.
Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory(NREL) phase VI wind turbine in downwind and upwind configurations is presented. The open source toolbox Open FOAM coupled with arbitrary mesh interface(AMI) method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.  相似文献   

20.
Most source number estimation methods based on the eigenvalues are decomposed by covariance matrix in MUSIC algorithm. To develop the source number estimation method which has lower signal to noise ratio and is suitable to both correlated and uncorrelated impinging signals, a new source number estimation method called beam eigenvalue method (BEM) is proposed in this paper. Through analyzing the space power spectrum and the correlation of the line array, the covariance matrix is constructed in a new way, which is decided by the line array shape when the signal frequency is given. Both of the theory analysis and the simulation results show that the BEM method can estimate the source number for correlated signals and can be more effective at lower signal to noise ratios than the normal source number estimation methods.  相似文献   

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