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This study discusses the effectiveness of using a balance chair and adjusting a desk height and working position for maintaining seating posture during light-duty work. It is important for a worker to maintain good posture to improve work efficiency and protect his or her health. However, the worker’s body trunk tends to lean forward unconsciously when he or she is working on an ordinary chair. Meanwhile, a person sitting on a balance chair, which comprises a forward-declined seat and a knee pad, can maintain a posture that resembles that of standing. This study measures the body trunk angles of a subject performing light-duty work while seated on an ordinary chair and a balance chair and discusses the influence of desk height and working position.

The assessment of the safety and reliability of double hull structure under the excessive lateral pressure requires the confirmation of buckling of the skin plate panels and the post-buckling behavior of the global structure. Recent progress of the analysis tool and expanded capacity of the computer system enables to solve such complicated problems gradually. However these analysis have not been effectively applied in the actual design stage yet because the global hull structure model is too large for this kind of nonlinear analysis. In order to accurately evaluate the post buckling behavior of whole double hull structure in a practical time, the authors have developed the new assessment system by the linear FEM analysis introducing simplified plate element with equivalent stiffness of buckled panel. This system enabled the evaluation of the post buckling strength of whole hull structure in very short time, and thus, the design for optimizing the arrangement and reinforcement of structure.

We have investigated the use of polyvinyl alcohol (PVA) hydrogels for hemiarthroplasty. The PVA-hydrogels were prepared in two different solvents using a low-temperature crystallization method. The first was a conventional mixture of water and dimethyl sulfoxide (DMSO), and the second comprised water only. The hardness and wear resistance of the PVAhydrogel mixed in water (PVA-H/Water) were compared with that of PVA-hydrogel mixed in a DMSO aqueous solution (PVA-H/DMSO). The results indicated no significant difference in the indentation hardness between PVA-H/DMSO and PVA-H/Water. However, the frictional coefficients of PVA-H/DMSO were larger than those of PVA-H/Water. Fewer wear tracks were observed in PVA-H/Water than in PVA-H/DMSO.

This paper describes a method for estimating the structural response of ship structures under water impact pressure. A series of drop tests of a cylinder with a diameter of 312 mm was carried out to measure water impact pressures and strains on the surface of a cylinder. Numerical analyses were carried out for one of the drop tests to reproduce the structural response under measured time history of pressures. In spite of the existence of large local vibrations shown in the numerically estimated strain values, the numerically estimated strain values and the measured values mainly showed the same tendencies. This result confirmed that the numerical method employed here can be used for this purpose. The effects of maximum impact pressure on the maximum strain value was evaluated. Two types of pressure histograms were used to estimate the maximum strain values. The strain values obtained from the pressure histogram with maximum impact pressure showed less effect than that without maximum impact pressure. Finally, the maximum impact pressure value of the measured time history of pressures to be used for numerical analysis was modified. One had the value of twice as much as the measured value and the other had the mean value of before and after the peak value. The results showed that the maximum impact pressure value itself has little effect on the maximum strain value, while the time integration of pressure seems to have more effect than that of maximum impact pressure.

This study evaluates the usefulness of endoscopic ultrasonography in the diagnosis of chronic pancreatitis. 52 patients with chronic pancreatitis, which included 15 cases of mild pancreatitis, 19 cases of moderate pancreatitis and 18 cases of advanced pancreatitis, were diagnosed by endoscopic retrograde cholangiopancreatography and further investigated by endoscopic ultrasonography. The 4 main findings of 1) dilatation of the main pancreatic duct, 2) irregularity of the main pancreatic duct, 3) inhomogeneity of the pancreatic parenchyma and, 4) irregular configuration of the pancreas were reviewed. In all of the 18 cases of advanced pancreatitis, irregularity of the main pancreatic duct, inhomogeneity of the pancreatic parenchyma and irregular configuration of the pancreas were seen. 89% of these patients had dilatation of the main pancreatic duct. In the patients with moderate pancreatitis, on the other hand, all 4 findings occurred with a frequency of between 58% to 95%. In the patients with mild pancreatitis, irregularity of the main pancreatic duct, inhomogeneity of the pancreatic parenchyma and irregular configuration of the pancreas occurred at a rate of 40% to 93%, and dilatation of the main pancreatic duct occurred rarely in only 13% of the patients. We were able to detect abnormalties in the pancreatic parenchyma by endoscopic ultrasonography even in the early stages of chronic pancreatitis, and this suggests that this technique may be useful in the diagnosis of mild pancreatitis, which usually causes quite minor abnormal changes in the main pancreatic duct.

This paper presents the procedure and the results of numerical simulations that are applied to an impact penetration test.As a result of an accidental explosion of an energy plant of a ship, such as a boiler or a turbine settled within an engine room, fragments may scatter with high speed and collide with wall plate. When fragments perforate through the wall plate around the engine room, the equipment and operators possibly be injured.A concept of protective wall gives one of the way to avoid such hazards. It is necessary to evaluate the protective capability of the wall, when designing the protective walls.First, an impact penetration test is carried out to evaluate the protective capability of a high tensile strength steel plate against the perforation failure. The test is performed with a powder accelerator to shoot the steel plate with a simulated fragment. The simulated fragment of a cylindrical shape is shoot with the speed of 413 m/s.Speeds of the fragment and a plug after perforation are measured by strain gauges and a high speed cinematograph during the test. Deformation of the fragment and the steel wall plate are also measured after the test.Next, numerical simulations are carried out to reproduce the experiment. DYNA3D code, a three dimensional elastic plastic large deformation impact contact problem analyzing program based on the finite element spatial discretization, is used to do numerical simulations of the test. The elastic-plastic model with failure is employed to express fracture phenomena occurred during the test.The fragment and the wall plate are assumed to be axially symmetric. The edge of the wall plate is fixed and the initial speed is applied to each grid of the fragment model. The speeds of the fragment and a plug after perforation are compared with the simulated values, changing parametrically the mechanical properties of the fragment and the wall plate. The effects of the mechanical properties on the speeds after perforation are obtained.As a result, a set of reasonable material properties is obtained by the numerical simulations. The experimental results are shown to be reproduced well by the numerical simulations with this set of material properties. The numerical simulation method is shown to be an efficient way to estimate the protection capability of a steel plate against the penetration caused by high speed fragments.

Endoscopic gastric mucosal resection (EGMR), by which a large specimen can be obtained, has been developed for the diagnosis and treatment of the borderline lesion (B. L.) or early gastric cancer (EGC), since biopsy specimens obtained by conventional techniques are too small to make an accurate diagnosis in number of cases. Thirty-eight lesions in 35 cases (26 lesions in 23 cases with B. L. and 12 lesions in 12 cases with EGC) were resected for the purpose of treatment by EGMR, and 24 lesions (6 submucosal tumors, 3 B. L. s, 14 cases of EGC and 1 malignant lymphoma) for the purpose of diagnosis. By means of histological examination of the bite biopsy specimens following EGMR, twenty-three lesions in 26 cases (89%) with a B. L. and 8 in 12 cases (67%) with EGC for treatment by EGMR were found to have been completely resected. After further histological examination of EGMR specimens obtained for diagnosis, one out of 3 B. L. s was diagnosed as EGC (IIa) and the others as bengin lesions. Out of 14 EGC cases, 6 were diagnosed as carcinoma, 3 as B. L. s and 5 as benign lesions. In Group III lesions obtained by conventional endoscopic biopsy, 8 out of 40 lesions (20%) were defined as EGC, 28 lesions (70%) as a B. L. and 4 lesions (10%) as benign lesions respectively by means of histological examination of the EGMR specimens. Although obvious side effects were observed in 4 cases, these patients could be treated by endoscopic management or drug therapy. It can be concluded that EGMR, by which large specimens can be obtained, is a useful procedure for the purpose of diagnosing and treating gastric mucosal lesions without causing major risk.

Aircraft jet engine should be designed to keep the required performance against for the event of foreign object ingestion, such as bird-strike. For the purpose to realize highly efficient and more advanced design of fan blade of jet engine, a numerical simulation technique for bird-strike problem has developed. Good agreement was obtained between simulation results and the soft body impact tests described in this paper. It was also shown that bird-strike problem has to be recognized as a fluid-structure interaction problem, because the impacted bird behaves like fluid and the impact force is highly influenced by the deformation of fan blade.Copyright © 2004 by ASME

The procedure and the results of numerical simulations which are applied to high speed tensile tests are presented. These tests are conducted to evaluate the failure behaviour of both mild steel and high tensile strength steel under high strain rate. The time history of the stress and the stress-strain relation are obtained from these tests. The tests are simulated numerically by “DYNA3D” code with an elastic-plastic model with failure. A parametric approach with the numerical simulation is employed by changing the material properties. As a result, reasonable material properties are obtained. The experimental results are shown to be reproduced well by the numerical simulations with these material properties for both the mild steel and the high tensile strength steel. The local failure behaviour, such as reduction of width at the failed section, is simulated well.

A numerical method is developed to estimate the failure behaviour of ice, and the model tests are carried out to verify this method. This method employs the thick-walled shell element based on the concept of the Rigid Bodies-Spring Models. This method is equipped with some functions to deal with characteristics of ice, such as material nonlinearities, geometrical nonlinearities, differences of material properties through thickness, buoyancy and self weight effects, and cracking behaviour. The verification tests of this method are carried out in the IHI ice tank on both level ice sheets and composite ice sheets including model ice ridge, and it is shown that the results of simulations have good correspondence with experimental results.

The purpose of this study is to examine the ultimate strength of resisting type collision barriers which are installed in nuclear ships. Two kinds of ship side structures containing such barriers were designed by way of experiment as examples. The characteristic of one is that it consists of a grillage of horizontal and vertical webs, and the other's is that more deck plates are set than usual. Four series tests were carried out on these structures as follows, (1) one deck element model tests against a rigid bow model, (2) structural model tests against a rigid bow model, (3) double-hull element model tests against a rigid bow model, (4) structural model tests against two actual bow models.From the analysis of the test results, the collapse modes were classified into two patterns such as crushing collapse of only the loaded region and bending collapse of the whole structure. The strength in the former collapse could be attributed to the ultimate strength of the members which were carrying a load directly beneath it, where an effective sectional area, which was calculated by the effective width formula, was taken into account. The latter could be explained considering a limit load obtained by the plastic hinge method, where an effective full plastic moment, which was calculated with a sectional area excepting the ineffective parts due to buckling, was taken into account.Finally, a way to estimate ultimate strength was derived for the above-mentioned two kinds of ship side structures.

This paper deals with model tests and their analysis conducted to evaluate the structural strength of double bottom for two types of stranding. Striking : The bow of a ship strikes a rock, which horizontally penetrates the bottom structure. Grounding : The ship grounds on a rock, which vertically penetrates the bottom structure depending on sea condition. For the striking test, 1/4 scaled double bottom models of steel plates were made representing the bottom of usual cargo holds and more stiffened bottom of engine rooms, etc. The rock model is a rigid square piller with leading wedge of angle 90°. For the grounding test, 1/8 scaled double bottom model was made representing the bottom of engine room, etc. The rock model is a rigid cone with apex angle of 90°. The rock model was set on the head of a 600 ton Amsler universal testing machine, and forced to penetrate the bottom model set on the moving bed.Following conclusions are obtained from analysis of test results.(1) In striking situation, crushed (buckled or torn) members such as bottom plate, inner bottom plate, longitudinals and girders would have the collapse strength of 80% yielding of their material, while deflected and ruptured members such as floors would induce membrane force in proportion to rock's penetration and subsequently break at yielding of their material with 20% elongation (in case of mild steel). This assumption gives very good estimation for the relation between load and penetration of the bottom structure.(2) In grounding situation, same assumption is also valid. In this case, crushed members are floors and girders, while ruptured members are bottom plate panels supported by floors and girders.(3) The damage of an oil carrier of about 100 thousand tons with double bottom is estimated using calculation formulas acertained by the model test. On striking a rock at the bow during fully loaded running, rock's penetration would reach O.20.5 of ship length. On grounding on a locally projecting rock, the bottom plate would be ruptured at rock's reaction of 900 ton, and the rock would reach the inner bottom plate at that of 3, 600 ton.