A direct method for speeding up the convergence of the furness biproportional method

This paper describes a direct non-iterative balancing technique which could be used as a complementary part to the Furness method to speed up the convergence to the final solution. This is particularly useful when the convergence of the Furness iterations is uneconomically slow and/or when high balancing accuracy is needed. The direct method however, might be used as a substitute to the Furness method in evaluating the consequences of a few alternative sets of small variations in the marginal totals of a two dimensional array.     

Effects of bulbous bow on cross-flow vortex structures around a streamlined submersible body at intermediate pitch maneuver: A numerical investigation

A flow field around a streamlined body at an intermediate angle of incidence is dominated by cross-flow separation and vortical flow fields. The separated flow leads to a pair of vortices on the leeside of the body; therefore, it is essential to accurately determine this pair and estimate its size and location. This study utilizes the element-based finite volume method based on RANS equations to compute a 3D axisymmetric flow around a SUBOFF bare submarined hull. Cross-flow vortex structures are then numerically simulated and compared for a submarine with SUBOFF and DRDC STR bows. Computed results of pressure and shear stress distribution on the hull surface and the strength and locations of the vortex structures are presented at an intermediate incidence angle of 20°. A wind tunnel experiment is also conducted to experimentally visualize the vortex structures and measure their core locations. These experimental results are compared with the numerical data, and a good agreement is found.     

Cavitation passive control on immersed bodies

This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator (ACG). Cyclic processes, namely, growth and implosion of bubbles around an immersed body, are the main reasons for the destruction and erosion of the said body. This paper aims to create a condition in which the cavitation bubbles reach a steady-state situation and prevent the occurrence of the cyclic processes. For this purpose, the ACG is placed on the surface of an immersed body, in particular, the suction surface of a 2D hydrofoil. A simulation was performed with an implicit finite volume scheme based on a SIMPLE algorithm associated with the multiphase and cavitation model. The modified k-ε RNG turbulence model equipped with a modification of the turbulent viscosity was applied to overcome the turbulence closure problem. Numerical simulation of water flow over the hydrofoil equipped with the ACG shows that a low-pressure recirculation area is produced behind the ACG and artificially generates stationary cavitation bubbles. The location, shape, and size of this ACG are the crucial parameters in creating a proper control. Results show that the cavitation bubble is controlled well with a well-designed ACG.     

基于耐波性试验采用棱镜致动器的新型三自由度并行机构开发的高速船运动模拟器的动力分析（英文）

In this study, we focused on a novel parallel mechanism for utilizing the motion simulator of a high-speed boat(HSB). First, we expressed the real behavior of the HSB based on a seakeeping trial. For this purpose, we recorded the motion parameters of the HSB by gyroscope and accelerometer sensors, while using a special data acquisition technique. Additionally, a Chebychev highpass filter was applied as a noise filter to the accelerometer sensor. Then, a novel 3 degrees of freedom(DoF) parallel mechanism(1T2R) with prismatic actuators is proposed and analyses were performed on its inverse kinematics, velocity, and acceleration.Finally, the inverse dynamic analysis is presented by the principle of virtual work, and the validation of the analytical equations was compared by the ADAMS simulation software package. Additionally, according to the recorded experimental data of the HSB, the feasibility of the proposed novel parallel mechanism motion simulator of the HSB, as well as the necessity of using of the washout filters, was explored.     

对台湾海峡隧道通行方式与施工方案的探讨

针对台湾海峡通道隧道与桥梁方案通行方式存在差异及施工技术更为复杂的问题,对通行电动汽车的可能性和隧道布置方案进行探讨,对台湾海峡隧道TBM施工的通风、运输、设备可靠性及工期控制等关键制约因素进行分析,认为从技术可靠、工期可控的原则出发,有必要布置人工岛对隧道施工段落进行分割。对人工岛的功能、结构方案提出了设想,对今后的研究工作提出了建议。     

医源性高位胆管损伤的外科处理

目的探讨医源性胆管损伤和狭窄的类型、重建时机、促成损伤因素及胆道重建技术等对疗效的影响。方法回顾性分析了94例医源性胆管损伤患者,分为术中诊断、术后早期发现、引流或重建术后又出现狭窄等3组接受胆道再建手术。结果本组病例无手术死亡情况。术中诊断的31例中,22例系未辨清胆囊管和肝总管、胆总管联合部。随诊3-15年,疗效优者75例(79.8%),良者13例(13.8%),优良率达93.6%,差者6例(6.4%)。差者中已死亡5例(占5.3%,5/94)。结论除熟悉病理解剖关系外,经验和谨慎对预防医源性胆管损伤至关重要。胆道重建的疗效主要受Bismuth分型和胆道重建技术等因素的影响。     

Development of 19-plex Y STR system and polymorphism studies in Pakistani population

For the development of 19-plex Y STR system and polymorphism studies in locl ethnic populations sixteen markers of non-recombining regions (NRY) of Y chromosome, which show high power of discrimination among individuals, were selected in this study. Blood samples (600) were e.ollected from the males of three most common castes of Pakistani population (Arnin, Awan and Rajput) with different parent lineages. Three markers (DYS385a/b, DYS389Ⅰ/Ⅱ and YCAⅡa/b) among 16 Y STRs are double-targeted regions of the Y chromosome and thus provide two polymorphie peaks for each respective primer set. These 16 Y-STRs were developed into Megaplex system for simultaneous amplification of all markers within the population. The overall power of discrimination observed in focused populations was 60.5%, 66.5% and 55% in Rajput, Awan and Arain casts respectively. This discrimination power will be helpful in haman identification for forensic casework studies including sexual assaults and paternity testing.     

Exposure to noise inside transit buses in Kuwait: Measurements and passenger attitudes

Noise levels were measured, for the first time, inside 115 randomly selected transit buses, operating on 12 sample representative routes in Metropolitan Kuwait. Simultaneously with the monitoring of noise levels, the attitudes of 679 riders concerning the annoyance and long-term health impacts of noise were also surveyed. The noise and passenger attitude data were collected over 10 months (March - December 2000). The percentile distribution, equivalent noise level, traffic noise index and noise pollution levels inside four types of transit buses are presented. Riders' perceived annoyance and awareness of the long-term health impacts of noise were also determined and are discussed. The level of service and performance deficiencies of the public transit system in Kuwait, as perceived by its passengers, are also identified. A number of recommendations end the paper.     

A fuzzy AHP decision support system for selecting yard cranes in marine container terminals

One of the most important issues that planners and developers of ports have to address at the planning process of container terminals is how to effectively optimize truck turnaround times. The time that a truck spends at a container terminal for loading and/or unloading of cargo is a real cost scenario which affects not only the smooth operation of ports but also the overall cost of the container trade. The main objective of this article is to provide a decision support tool for selecting the best container yard gantry crane for loading/discharging operation of trucks at the landside of marine container terminals. Achieving this goal, this study aims at introducing and recommending the multiple attribute decision-making and the fuzzy analytical hierarchy process models that have been proven to provide a concrete basis for such a selection decision.     

作用在双圆柱桩上波浪力准确解和有限差分解的比较

The wave force exerted on vertical piles of offshore structures is the main criterion in designing them.In structures with more than one large pile,the influence of piles on each other is one of the most important issues being concerned in past researches.An efficient method for determining the interaction of piles is introduced in present research.First the wave force is calculated by the exact method using the diffraction theory,then in the finite difference numerical method the force is calculated by adding the velocity potentials of each pile and integration of pressure on their surface.The results showed that the ratio of the wave force on each of the double piles to a single pile has a damped oscillation around unity in which the amplitude of oscillation decreases with the increase in the spacing parameter.Also different wave incident directions and diffraction parameters were used and the results showed that the numerical solution has acceptable accuracy when the diffraction parameter is larger than unity.