PMM tests in a circulating water channel and nonlinear analysis

As a result of frequent marine disasters leading to the loss of human life and pollution of vast areas of the ocean, ship manoeuvrability has become a very important characteristic of ship design. Among several recent experimental techniques to determine ship manoeuvrability, the most popular is captive model testing using a planar motion mechanism (PMM). This article describes some tests, analyses, and results of PMM tests in a circulating water channel (CWC) using a model of a training ship. The hydrodynamic forces and moments acting on a model of the training ship Shioji Maru in pure yawing motion were measured, and hydrodynamic derivatives were obtained using two different methods of analysis: singular value decomposition (a least-squares fit method) and Fourier analysis. Derivatives obtained from the tests were used to simulate the turning trajectory of the actual ship, and these were compared with the results of sea trials. The results indicate that both methods of analysis yield fairly similar derivatives. The simulation results were also found to be a close match with the trial results. Received: February 7, 2002 / Accepted: May 14, 2002 Address correspondence to: K. Shoji (shoji@ipc.tosho-u.ac.jp)     

膨胀石墨吸油特性的研究

通过对不同形态和填充密度的膨胀石墨(EG)进行的毛细吸附实验，着重研究了EG的比表面积和填充密度对吸油特性的影响．实验结果表明：细颗粒状EG样品的比表面积从O．624m^2／g到34．20m^2／g显著变化时，对柴油吸附率的改善并不显著；与细颗粒状EG样品相比，大颗粒蠕虫状样品具有更高的吸附率；填充密度的变化对A级重油吸附率有显著影响．     

Limits to resources, economic growth and happiness

Terrible scenario for the future aspect of our society was issued by “The Limits to Growth”. Basic problems that we confront are the restricted natural resources and the environment. Regarding the resources, the overall average of the reserve/production ratio is predicted to fall below 10 years by 2040. Aggressive developments of mines based on the sense of urgency for metal resources cause strong confliction with the environment and the people living there. Resultantly, urban mine becomes more realistic than before. From the view point of ecological foot print, 5.3 globes are needed if all the people living in the world attain the affluent life same as USA. On the other hand, it is clear that we can get larger utility by smaller goods if our scale of satisfaction is reduced. We have to notice that happiness is our ultimate purpose, economy and industry are intermediate, and natural resources support the all from the basis.     

Basic studies on accuracy management systems based on estimating welding deformations

Accuracy management concerns various aspects of all assembly industries, e.g., final product quality, manufacturing efficiency, and manufacturing costs. In the near future, accuracy management will be even more important in manufacturing systems because of mechanization and automation. This paper considers the concept of computer-aided accuracy management systems, which are based on the concept of integrated manufacturing systems. We propose two management systems, accuracy planning and accuracy estimation, and concentrate on accuracy planning. A model of welding deformations and an easy estimation method for such deformations by computer analysis using the finite element method (FEM) are described. A prototype system based on the accuracy management concept was implemented in the authors' integrated manufacturing systems, and some examples of estimating welding deformations are given here. Translation of an article that appeared in the Journal of The Society of Naval Architects of Japan, vol. 181 (1997): The original article won the SNAJ prize, which is awarded annually to the best papers selected from the SNAJ Journal, JMST, or other quality journals in the field of naval architecture and ocean engineering.     

Studies on the block positioning metrics system for the hull erection stage

In ship hull production, the accuracy of management activities is extremely important. The block positioning operation in the erection stage is a key process in such management. The quality of the block positioning determines not only the accuracy of the final hull, but also the productivity and cost at the erection stage. We have previously proposed the basic concepts of computer-aided accuracy management. Accuracy management activities consist of "accuracy planning activities" and "accuracy measurement activities." Accuracy measurement activities involve checking and coping with inaccuracy. We have also proposed a system of accuracy measurement metrics: one is accuracy for completion (e.g., straightness, flatness), and the other is accuracy for construction (e.g., the relative joint shapes of each part). This paper explains the detailed accuracy metrics for a block positioning operation in the erection stage. The quality of the block positioning operation is estimated by this system: the accuracy of the completed hull can be evaluated by the concept of tolerance, and the accuracy of the construction process can be evaluated by the concept of labor costs. The prototype of this accuracy metrics system is then implemented. This metrics system is combined with the optimization software program iSIGHT to decide the best block positioning process. Then some examples of the block position optimizing process are shown. Received: November 2, 2001 / Accepted: December 6, 2001     

The effect of governmental subsidies and the contractual model on the publicly-owned bus sector in Japan

The publicly-owned municipal bus sector that provides local transport in Japan is in a difficult situation because of operating deficits, inefficient operations and management, and budgetary constraints of expanding subsidies, and thus, it needs to be restructured to improve efficiency. This paper investigates the impact of subsidies and contractual settings on the cost structure of the publicly-owned bus sector in Japan. A trans-log cost function has been estimated by pooling cross-sectional data of 527 observations over the time period of 1990-2006 for a cross-section of 31 publicly-owned transport companies in Japan. Our analytical results confirm that governmental subsidies to this sector negatively affect the cost structure, while the contractual model may have a positive impact. We also discuss the implications of these results for Japan’s public transport policy.     

THE MIB-1 PROLIFERATION INDEX AND MICROVESSEL COUNT IN EARLY GASTRIC CANCER: ASSOCIATION WITH LYMPH NODE METASTASIS

Ki-67 antigen['J, which can be detected usingthe MIBl antibody['J, is a cell proliferation associ-ated nuclear antigen present in all stages of the cellcycle except G,, and thus the proliferation indexdetermined by MIB--1 reflects the cell proliferation.Recently, proliferative activity as evaluated usingthe MIB -l proliferation index (MIB-1 PI) hasbeen shown to be a prognostic factor in several tu-mors[3J. Tumors with low angiogenic activity havea reduced risk of recurrence and metastas…     

Forecasting bus ridership using a “Blended Approach”

Transportation - As sources of “Big Data” continue to grow, transportation planners and researchers seek to utilize these new resources. Given the current dependency on traditional...     

HCCI combustion characteristics during operation on DME and methane fuels

The Homogeneous Charge Compression Ignition (HCCI) engine has attracted much interest because it can simultaneously achieve high efficiency and low emissions. However, the ignition timing is difficult to control because this engine has no physical ignition mechanism. In addition, combustion proceeds very rapidly because the premixed mixture ignites simultaneously at multiple locations in the cylinder, making it difficult to increase the operating load. In this study, an HCCI engine was operated using blended test fuels comprised of dimethyl ether (DME) and methane, each of which have different ignition characteristics. The effects of mixing ratios and absolute quantities of the two types of fuel on the ignition timing and rapidity of combustion were investigated. Cool flame reaction behavior, which significantly influences the ignition, was also analyzed in detail on the basis of in-cylinder spectroscopic measurements. The experimental results revealed that within the range of the experimental conditions used in this study, the quantity of DME supplied substantially influenced the ignition timing, whereas there was little observed effect from the quantity of methane supplied. Spectroscopic measurements of the behavior of a substance corresponding to HCHO also indicated that the quantity of DME supplied significantly influenced the cool flame behavior. However, the rapidity of combustion could not be controlled even by varying the mixing ratios of DME and methane. It was made clear that changes in the ignition timing substantially influence the rapidity of combustion.     

Maneuvers of motorcycles in queues at signalized intersections

The maneuvering models of motorcycles in previous studies often considered motorcycles' traveling in terms of movements in a physical static lane and not in terms of dynamic virtual lane‐based movements. For that reason, these models are not able to imitate motorcyclists' behavior well. This paper proposes a maneuverability model framework for motorcycles in queues at signalized intersections with considering the dynamic motorcycle's lane. The model includes (i) a dynamic motorcycle's lane to identify the current, left, and right lanes of the subject motorcycle, (ii) a threshold distance to determine when a motorcyclist starts to consider maneuvering, (iii) a lane selection model to identify the lane preferred by a motorcyclist, and (iv) a gap acceptance model to describe whether or not the lead and lag gaps are acceptable for maneuvering. The model framework captures the variation across the motorcyclist population and over time observations. The models were applied to Hanoi and Hochiminh city, Vietnam, based on microscopic data collected from video images. All of the parameters were estimated using the maximum likelihood method with the statistical estimation software GAUSS. The results show that 77.88% of the observed maneuvers – either staying in the current lane or turning left or right – could be modeled correctly by the proposed models. Copyright © 2010 John Wiley & Sons, Ltd.