附录：PortletConfig对象详解

本部分将讲述PortletConfig对象及其PortletContext对象的概念及应用。     

Error analysis of indirect force determination and a regularisation method to reduce force determination error

Accurate estimation of dynamic forces acting on a structure is very difficult, since, at certain frequency regions, the identified forces may contain an unacceptable amount of error. In this study, by investigating the characteristics of the inverse transfer function and frequency response function (FRF) error, the indirect force determination error is analysed statistically, and the special frequency regions where force determination error is very large are searched for each case of the number of response measurements and applied forces. It is shown that the large force determination error near the first kind of inverse pole frequencies is mainly due to the rank deficiency of the FRF submatrix, while the large error in the vicinity of resonance frequencies comes from the larger FRF error. The idea was tested both analytically and experimentally. Also a regularisation process to reduce the error especially near the first kind of inverse pole frequencies is proposed. Since the degree of singularity of the FRF submatrix near the first kind of inverse pole frequencies is mainly related to system damping, a regularisation procedure is suggested by adding additional damping. An optimal regularisation constant is also derived. It is shown that, the greater the order of magnitude of the FRF error is than that of modal damping ratio, the larger the force determination error reduction is obtained with the suggested regularisation procedure. The proposed regularisation method was tested experimentally and its effects examined.     

Awardee Selection Procedures,With Special Reference to the Frank Wilcoxon and Jack Youden Prizes

The selection procedures used currently and since 1977 for award of the Frank Wilcoxon and Jack Youden prizes are described. Using real data from the 1976 awards competition, it is shown that different methods of combining judges' ratings would yield different winners, and that which procedure is best is not intuitively obvious. Finally it is shown how the current method was chosen on the basis of probability of correct selection considerations.     

非线性系统的观测反馈线性化及其在活性污水处理过程中的应用

本文首先证明了一类非线性系统完全线性化的充分和必要条件,并且提出一种用于线性化系统的闭环观测器的设计方法,然后将上述结果具体地运用在活性污水处理过程的研究。计算机模拟结果表明:具有闭环观测器的完全线性化方法是行之有效的。     

An intelligent real-time multi-vessel collision risk assessment system from VTS view point based on fuzzy inference system

Due to brisk industrial growth, the marine traffic has become an imperative subject in the open sea nowadays. The crew inside the vehicle traffic service (VTS) centre is facing challenging issues on account of continuous growth in vessel number. Currently, most of VTS centers’ are using the ARPA RADAR based conventional vehicle traffic management system and VTS staff has to carry out most of the things manually to guide the ship’s captain properly. Therefore, there is a strong impetus in the field of ocean engineering to develop a smart system which can take the data from RADAR and autonomously manipulate it, to calculate the degree of collision risk among all vessels from the VTS centre. Later on, the traffic management officer utilizes this information for intelligent decision making. In the past, several researchers have addressed this issue to facilities the VTS crew and captain of the ship but mostly, their research work was for academic purposes and could not get popularity because of extra manual workload. Our proposed vessel collision risk assessment system is an intelligent solution which is based on fuzzy inference system and has the ability to solve the said issues. We calculated the DCPA, TCPA, bearing and VCD among all vessels ships from the VTS centre by using conventional marine equipments and exploited the extracted information to calculate and display the degree of collision risk among all vessels. Furthermore, we developed the RADAR filtration algorithm which helps the VTS officer to gauge out the degree of collision risk around a particular ship. To authenticate the validity and to monitor the performance efficiency, we developed RADAR operated intelligent software which directly gets the required data from RADAR and displays the vessels list based on their degree of collision severity. The laboratory experiments confirm the validity of the proposed system.     

Multipurpose simulation network with a single amplifier

A network consisting of an operational amplifier, one or two capacitors and several resistors can be connected to form several f.d.n.r. circuits or an inductance-simulation circuit.     

EFFECT OF CARBON AND BORON ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A SINGLE CRYSTAL SUPERALLOY RR 2072

Carbon and boron have been considered to strengthen grain boundaries that might form during single crystal casting. In this study the effect of boron on solidification behavior and creep properties of the carbon doped single crystal RR 2072 has been investigated. In order to understand solidification behavior with boron addition, the solid/liquid interface morphology and solidification microstructare were examined with solidification rate. The relationship between microstructaral evolution and creep properties of the carbon and boron modified single crystal has been also investigated.     

Evaluation of Enhanced Heat Transfer Within a Four Row Finned Tube Array of an Air Cooled Steam Condenser

Air cooled steam condensers (ACSC) consist of finned-tube arrays bundled in an A-frame structure. Inefficient performance under extreme temperature operating conditions is a common problem in ACSCs. The purpose of this study was to improve the heat transfer characteristics of an annular finned-tube system for better performance in extreme climatic conditions. Perforations were created on the surface of the annular fins to increase heat transfer coefficient (h). Mesh generation and finite volume analyses were performed using Gambit 2.4.6 and Fluent 6.3 with an RNG k–? turbulent model to calculate pressure drop (ΔP), heat flux (q), and heat transfer coefficient (h). Solid (no perforations) finned-tubes were simulated with free stream velocity ranging between 1 m/s–5 m/s and validated with the published data. Computations were performed for perforations at 30° interval starting at ±60°, ±90°, ±120°, ±150°, and ±180° from the stagnation point. Five cases with single perforation and three cases with multiple perforations were evaluated for determining the maximum q and h, as well as minimum ΔP. For the perforated case (perforations starting from 60° at interval of 30°), the fin q and h performance ratios increased by 5.96% and 7.07%, respectively. Consequently, the fin ΔP performance ratio increased by 11.87%. Thus, increased q and h is accompanied with a penalty of higher ΔP. In contrast, a single perforation location at 120° provided favorable results with a 1.70% and 2.23% increase in q and h performance ratios, respectively, while there was a relatively smaller increase (only 1.39%) of ΔP performance ratio. Perforations in the downstream region at ±120°, ±150°, and ±180° also resulted in a similar favorable outcome. Furthermore, the spacing of the fins along the arms of an A-frame ACSC was altered to decrease ΔP across the finned-tube array. Fin spacing in the A-frame structure with sparsely spaced fins in the center resulted in a 1.80% reduction in ΔP. Thus, penalty in ΔP for a perforated fin can possibly be offset by changing the fin spacing along the arms of an A-frame structure.     

Time-dependent nanoscale plasticity of ZnO nanorods

External stresses are applied during operation or storage in flexible electronics, which makes understanding time-dependent plastic deformation of nanobuilding blocks more crucial for ensuring the reliability of the devices. Here, we systematically explored the time-dependent nanoscale plasticity of single-crystal ZnO nanorods and its size effects. A series of compression creep tests under different low stresses (in elastic regime) were performed on vertically oriented rods having equivalent diameters in the range of ～200 to ～2000 nm. It was revealed that creep indeed occurs in the rods even at ambient temperature, and is more pronounced in smaller nanorods. Analyzing the stress exponent and the activation volume suggests that the enhanced plasticity may be controlled by the diffusion creep (through the “space-charge layer” near the surface and/or along the interface between the punch and the top surface of the rod), which is supported by the results from in situ creep tests under electron-beam irradiation and in situ electric measurements.