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Knee extensors play a key role in maintaining balance and stabilizing gait. Insufficient training of knee extensors leads to muscle atrophy and progressive overall body instability. However, training knee extensors requires specific exercises which are not easily integrated in activities of daily life. For example, even if walking is one of the most popular daily exercise, its training effects are limited to lower leg muscles. To better integrate knee extensor training in daily life we are developing a training device which can apply additional mechanical load on the knee joint during daily normal walking, to extend the training effects of simple walking to knee extensors. We projected a longterm study to develop an integrated system which combines a training function with an assisting function. Integrated sensors measure the biological data of muscular activity to automatically select the proper mode in real-time. In 2019, we designed a prototype of the training device and evaluated its effects on the knee extensor muscle with preliminary experiments. The results validated the feasibility of the training system and showed that the training load need to be adapted to the gait phase during walking. In this study, we improved the training device with active resistance component to adjust the training load in real-time.

This paper describes the motion characteristics and cargo handling efficiency of the Large-Scale Floating Coal Transshipment Station (LFTS). Indonesia is the main country supplying coal in the Asia-Pacific region, it is important to ensure stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. And then, Large-scale Floating Transposition Station for Loading Coal (hereafter LFTS) was proposed, which will be used as a transposition station between small coal barge coming down the river and bulk carriers stay offshore. By installing LFTS, improvement of coal transport efficiency is expected. As a previous study, the motion characteristics of LFTS using a catenary chain in its mooring system were grasped. However, LFTS can carry up to 500,000 tons of coal, and the draft of LFTS tends to change greatly depending on the coal loading conditions. Besides, the tidal difference in the sea area where the LFTS is installed is about 2 m, and the mounting position of the mooring system on the LFTS side moves up and down by about 10 m at maximum due to changes in the draft and tidal differences. For this reason, when the mounting position of the mooring system is in the lowest state, the mooring line is loosened and the horizontal force is reduced, and it is considered that sufficient restraining force is not exhibited. And, when the mounting position of the mooring system becomes high, the mooring line tension increases and the mooring line may break in some cases. Therefore, in this study, an attempt was made to use an elastic mooring line as a mooring system for LFTS. An elastic mooring line is a mooring line that incorporates a highly stretchable material between mooring lines that connect anchors and floating body. Even if the mooring line attached to the LFTS moves up and down, an appropriate tension always acts on the elastic mooring line, and it can be expected to suppress the oscillation of the floating body and prevent the mooring line from breaking due to excessive tension. However, elastic mooring lines are mainly used for mooring small structures such as piers and aquaculture facilities, but there are no examples where these mooring lines have been applied to structures over 500m like LFTS. Therefore, elastic mooring lines are adopted for the mooring system of LFTS, systematically calculated according to various setting conditions of elastic mooring lines, and it is grasped whether elastic mooring lines can be applied to LFTS, and the motion characteristics of LFTS moored by elastic mooring lines was also grasped.

Indonesia is the main country supplying coal in the Asia-Pacific region, and in order to secure a stable supply of coal to neighboring countries, efficient coal transportation is required. East Kalimantan Island in Indonesia is the main coal-producing area, but the sea around the island is very shallow and bulk carriers for transporting coal cannot approach the coast. And then, Large-scale Floating Transposition Station for Loading Coal (hereafter LFTS) was proposed, which will be used as a transposition station between small coal barge coming down the river and bulk carriers that stays offshore. LFTS has a two-dimensional extent, and because the bulkheads for separating coal according to quality are installed on the floating body, the rigidity is partially different, and the draft also changes greatly according to the coal loading condition. In this way, LFTS has different characteristics from Mega-Float, which was built in Japan in the late 1990s with the aim of realizing a floating airport, so it is important to clarify its structural characteristics. In order to grasp the stress distribution acting on the structural member in consideration of the influence of the interaction between the overall deformation and the local deformation of LFTS, an analysis in which the entire structure is modeled in detail is desired. However, because members such as the internal bulkheads are arranged in a complicated manner in LFTS, a model in which the entire structure is modeled in detail requires enormous calculation costs in both capacity and time, it is difficult to perform the analysis. In existing research, various models have been studied, but there remains a problem in setting boundary conditions that reproduce the interaction between global and local deformations. And then, in this paper, a new modeling method of LFTS that can be analyzed efficiently was proposed. And the occurrence of stress concentration in the structural members of the LFTS was identified by systematically changing the external force conditions such as the coal loading condition and wave load assumed during the operation of the LFTS, and performing LFTS oscillation analysis and stress deformation analysis. Furthermore, the occurrence of plastic strain due to large deformation was investigated. The stiffening method that efficiently suppresses the occurrence of plastic strain was studied for the locations where the plastic strain was identified by the above analysis. These results demonstrate the importance of modeling large floating structures with complex structures.

In this study, we consider and evaluate the applicability of the FEMA’s formula which is one of the main simple formulas for calculating impact forces through the comparison with our proposed numerical simulation model. We investigated the situation of collision with a thin structure such as a pillar by numerical experiments based on the particle method, in particular, we focus on the case where the drifting speed is fast in targeting the quay of Shimizu Port, Shizuoka prefecture. We compared the results of numerical experiments obtained by detailed simulations with FEMA’s formula and evaluated the applicable range of FEMA s formula for huge vessels. As results, it was suggested that the overestimation was occurred with FEMA’s formula for large vessel using the inundation height and its velocity. FEMA’s formula calculates the impact force of large vessel on the safe side if the drifting vessel speed is used: the condition of added mass coefficient changes the results, but these indicate the safe side in this study. On the other hand, the results of safety sides are fluctuated depending on the height of the action point of force. Therefore, we confirmed that there is a need to examine the height of the impact point when using FEMA’s formula for large vessels.

Oscillating water column (OWC) type wave energy converters (WECs) have been researched and developed. OWC WECs are relatively friendly to maintain them in operation because all of mechanical units are set above a sea water surface. In addition, a feature of an OWC device is similar to an air dumper system. Thus, it should be possible not only to harvest wave energy but also to reduce motion of a floating system at the same time. As well as WEC system should be used with other ocean renewable energies as a combined system. This paper describes hydrodynamic characteristics of OWC devices and wave fields around them of multi-OWC devices equipped large floating structures. For this research, the linear potential theory based in-house programme code was applied to calculate hydrodynamic performance of OWC regions and elastic motion behaviours of the structures. Besides, calculation results were compared with some experimental results of characteristics of OWC devices on reference papers published. Then we proved validity of the calculation method. We have quantitatively summarized how much the reduction effect can be seen according to the aircushion placement and the number of aircushions on the floating body. the paper investigated arrangement of OWC devices on the floating structure with several variations. Using the prediction method, effects of arrangement of OWC devices on the performances are investigated.

This paper describes scale effects and influence of configurations of oscillating water column type wave energy converters from model tests and theoretical calculations. Many researches regarding wave energy converters (WECs) have been conducted. The behavior of an oscillating water column of an OWC type WEC is complicated because of including wave-air-turbine interaction, and thus several issues remain. One of the issues is that influence of difference in scale between small scale experimental models and full scale models is unclear. It is important to understand its characteristics accurately to improve design technologies for such as complicated systems. In this study, we carried out forced oscillation tests using multiple scales and shapes of OWC models in still water, and measured the pressure inside the air chamber and the internal mean water level with a multi-line wave probe. The experimental models used have a box like air chamber or manifold type air chamber, and which scales were 1/1, 1/2 and 1/4.The difference of the two air chambers is an orifice or a duct to be inlet-outlet of air. As a result, the difference in scale and configuration of the air chamber affected the characteristics of the air chamber. In addition, as a result of numerical calculation using the linear potential theory and comparison with experimental results, the experimental results could be reproduced by numerical calculation. Besides, we could discuss the effects and the influences of the air chamber basically.

The Great East Japan Earthquake that occurred in Japan in 2011, an innumerable number of buildings in the coastal part of the east side of Japan suffered catastrophic damage, and medical facilities in coastal areas have become dysfunctional because of the significant damage incurred due to the tsunami. And land routes are not passable, but there are records of support activities utilizing water areas such as sea and river networks being extremely effective in such disaster conditions. Therefore, as one of the effective methods of medical support in the affected area immediately after the disaster, a Floating Medical Support System (hereafter Medi-float) on big disaster that can be accessed from the water area was proposed. In the near future, the area along the Arakawa River is expected to be seriously damaged by the earthquake directly under the Tokyo metropolitan area. Therefore, by installing a Medi-float that can perform medical support activities from the water area to the land without being damaged by an earthquake, since Medi-float performs medical support activities in cooperation with medical facilities on land area, preventable death is reduced. In previous studies, a procedure to estimate the facilities scale and select a suitable site for Medi-float practically based on GIS data such as the number of collapsed buildings in the target area, distribution of injured people due to the earthquake were presented. However, even if Medi-float is installed in the target area, it cannot be denied that there is a shortage of medical facilities. In consideration of smooth transportation outside the region and cooperation with surrounding medical facilities, it is hoped that a concrete and realistic medical support system by Medi-float will be established. Therefore, in this study, in order to grasp the time it takes for the injured to be transported to the medical facility and the congestion status of the medical facility, the target area was divided into 250m meshes and a time-series simulation was performed. Specifically, the distribution of injured people during a disaster was calculated on a mesh basis from the number of buildings collapsed and the number of fires. And the transport time of the injured people is calculated from the distance between each mesh and the medical facility, the movement of the injured people in consideration of the congestion status of the medical facility was simulated, necessity of cooperation between medical facilities and wide area transportation was clarified, the effect of Medi-float, which is active in the disaster area, was also evaluated.

This paper describes characteristics of motion responses and tether tensions of a floating structure with four moon pools, on which one or two vertical axis wind turbine models are installed. Effects of several moon pools founded in a floating structure on motion characteristics have been unclear. In this study, the authors proposed a twin-VAWT installed floating system, which was a pontoon based structure. However four moon pools were set on. The study conducted model experiments in a wave tank using regular waves with 0.6 to 2.0 seconds in wave periods and 0.02 and 0.04 m in wave height. The model had four moon pools and was installed with one or two vertical axis turbine models. From it, gyroscopic moment effects were investigated. Besides, the study performed numerical calculations with the linear potential theory based method which were a Green function method. As a results, responses of the twin-turbine model are not affected by gyroscopic moment. The study discusses motion responses and tether tensions with nonlinear behaviours from mainly the experimental results. Also the effect of moon pools were investigated from the calculations. From comparisons of motion results on calculation models with same displacement but different draft, the results suggested that not only heave motion but also roll motion could be reduced because of the moon pools if the size of the moon pools were optimized.

Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, Large-Scale Floating Coal Transshipment Station (LFTS) was proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. LFTS can store coal equivalent to five times the capacity of one bulk carrier (total 500,000T), and can accommodate 2 bulk carriers at the same time during offloading. The scale of LFTS is 590m × 160m. The LFTS has a flat spread and the elastic behavior becomes the dominant Structure. The upper part of the LFTS is different rigidity partly because the partition wall to be loaded by dividing the coal into each quality is provided. Loaded coal not only changes the draft of the LFTS but also greatly deforms the LFTS and is expected to cause local stress concentration on the structural members. Therefore, this paper investigates wave response characteristics and stress characteristics with the coal loading of the LFTS, and then evaluation of structural strength by limit state design method. In this study, linear potential theory and the finite element method (FEM) were used to analyze the static hydroelastic motion under various coal loading condition and wave response of LFTS. And, to grasp the local stress concentration occurring inside the LFTS by using the response results, a detailed model modeling a complicated internal structure was prepared. Zooming analysis which is a method of giving the deformation result by the whole model of LFTS as forced displacement to the local detailed model was carried out. As a result, depending on the coal loading condition and wave conditions, it became clear that LFTS will be in a tough situation.

Oscillating water column (OWC) types of wave energy converters have still several issues to be studied because system including wave-air-turbine interaction is complex. Besides, scale effects between small scale models and full scale models have not been definite. Although the effect in initial design of OWC devices might been able to be ignored, it is important to understand its characteristics exactly. The present study carried out forced oscillation tests in a water tank corresponding to the radiation problem. Three models whose scale are 1/1, 1/2 and 1/4 were used. In the forced oscillation test, we measured mean water elevation in an airchamber to predict the air flow rate and air pressure inside of the airchamber. From the mean water elevation and the air pressure, the primary power conversion was calculated. As a result, the pressure and the elevation were affected by not only the scale reduction but also the difference of airchamber volume. Variation of the volume of an airchamber affected on hydrodynamic performance sensitively.

In 2011, Japan experienced a major catastrophe: The Great East Japan Earthquake and subsequent tsunami. After the tsunami struck, overland transport routes were cut off, and consequently, emergency supplies and people requiring medical attention could not be transported very efficiently. Many hospitals and other emergency facilities were destroyed or were operating with reduced capabilities during this period, meaning victims could not receive treatment within a reasonable timeframe. Therefore, we need to consider emergency facilities, particularly for medical support, which are resilient and versatile for use in such situations. Floating bases for disaster relief and support ships are already available for deployment along coastal regions or on rivers near affected areas. A medical support floating base has also been proposed, which is called the Medi-float hereafter, in preparation for the anticipated Tokyo Inland Earthquake. And it is determined that the primary function of this Medi-float should be as a dialysis treatment center during normal operation and primarily for the treatment of crush syndrome patients during a disaster. But the original proposal was deemed inadequate in terms of facility scale and selection of the suitable site of Medi-float. Therefore, in this research aiming at realization of Medi-float, firstly the number of people who develop crush syndrome in the target area is estimated by GIS based on the damage prediction of the huge earthquake striking Tokyo and the risk of building collapse. Based on the distribution of dialysis treatment facilities and data such as road network data in Tokyo, Voronoi diagrams were created using GIS. And facility scale required for Medi-float and suitable installed site were examined by the distribution of crushed syndrome patients obtained by analysis and Voronoi diagram.

This paper describes characteristics of motion responses and tether tensions of a floating structure with four moon pools, on which one or two vertical axis wind turbines are installed. In this study, the authors proposed a twin-VAWT installed floating system, which was a pontoon based structure. However four moon pools were set on. The study conducted model experiments in a wave tank using regular waves with 0.6 to 2.0 seconds in wave periods and 0.02 and 0.04 m in wave height. The model had four moon pools and was installed with one or two vertical axis turbine models. From it, gyroscopic moment effects were investigated. Besides, the study performed numerical calculations with the linear potential theory based method which were a Green function method. As a results, responses of the twin-turbine model are not affected by gyroscopic moment. The study discusses motion responses and tether tensions with nonlinear behaviours from mainly the experimental results.

One of the reasonable methods to analyze the collision force of a tsunami drifting object against a structure is a particle method. However, when both the structure and the drifting body are composed of particles, there are various problems such as particles of the collision object slipping through particles of the structure. Therefore, the authors have constructed a particle method - analytical solution hybrid method which can analyze the collision force of a tsunami drifting object to an elastic member by constructing a structure as a boundary condition acting on a drifting object. However, since this boundary was introduced as a virtual boundary that acts only on drifting particles, the collision force of the tsunami drifting object to the structure can be analyzed, but the fluid force can’t be analyzed. Therefore, in this study, in addition to the boundary condition as the structure, we further reconstructed the collision force and the fluid force as a method that can analyze the collision force and the fluid force simultaneously by setting the mirror particle boundary condition for the fluid particle. By developing this method, it became possible to calculate the collision force in a situation where a stagnation point occurs like a flow field at the front of the wall type structure, and the drifting object is decelerating.

Several types of oscillating water column (OWC) type wave energy converters (WECs) are researched and developed in the world. They are floating types and fixed types. In case of a fixed type, wave-dissipating caissons could be replaced by WECs of an OWC type. In OWC types, installation of the projecting walls (PWs) is useful in order to improve power take-off (PTO) performance. In this study, a double-dissipating caisson was used as an OWC type WEC with PWs. A front caisson of the double caisson seems to be the area surrounded by PWs and a back caisson can be seen as an OWC. The paper studied the basic property of the primary conversion from wave power to pneumatic power from model tests in a wave tank. It was found that the wave height strongly affects the behaviors of OWC motion and air pressure. Finally, the primary conversion was affected by wave height. Besides, the concept of use of a double caisson was useful for the primary conversion over 80% evaluated using test data.

The large-scale tsunami generated by the Great East Japan Earthquake on March 11, 2011 caused a great deal of damage. In addition to tsunami hydrodynamic forces, loads generated by drifting objects such as ships and cars can cause destruction in coastal areas. As such, impact forces due to collisions of drifting objects are an important consideration in the design and planning of structures in coastal areas. Depending on the size of the drifting object, it is difficult to evaluate the effect of the impact force at the time of collision through tank experiments. Therefore, it is necessary to develop a numerical simulation method that can reasonably evaluate such effects. Such a method must consider the nonlinear interactions among drifting objects, a fluid, and fixed structures. In the present study, we used the moving particle semi-implicit (MPS) and finite element methods to calculate the effect of collisions between drifting objects and structures, and then verified the results experimentally. The MPS method was applied to calculate the loads and pressures due to the collisions. These results were then used to simulate the deformation of the structure using the finite element method. A tank experiment was then conducted in order to confirm the accuracy of the numerical calculations. The deformation of a rod-shaped steel structure was measured following collision with a floating acrylic plate. The experimental results confirmed the accuracy of the numerical calculations.

This paper describes the motion characteristics and cargo handling efficiency of the Large-Scale Floating Coal Transshipment Station (LFTS). Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, LFTS is proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. By installing LFTS, improvement of coal transport efficiency is expected. In considering feasibility of the LFTS system, it is important to know the cargo handling operation rate in the target area, LFTS can load 500,000 tons of coal and the draft will fluctuate greatly depending on the loading condition of coal. Therefore, when the draft is shallow, the freeboard becomes large and resonates with long-term component of the wind load and when the draft is deep, the wave force and fluid force including the slowly varying wave drift force affect the fluctuation. Also, LFTS and bulk carrier are large-scale structures, the fluid forces acting on both affect each other, so the influence of hydrodynamic mutual interference between two floating bodies cannot be ignored. In this study, fluid analysis in consideration of the hydrodynamic mutual interference of LFTS system is conducted. And, response analysis of LFTS and a bulk carrier in irregular wave which considered compound external forces such as wave load and slow varying wave drift force, wind load, tidal current was performed. As a result, it was confirmed that the motion response of LFTS was not upset because LFTS was large. Therefore, without considering the motion response of the LFTS, the cargo handling efficiency is calculated from the response analysis results of the bulk carrier and the oceanic condition of the setting sea area. As a result, the cargo handling efficiency is satisfied in the state where bulk carrier is installed leeward of LFTS, and it was confirmed that the LFTS system could be operated satisfactorily if the installation was appropriate.

Sea areas around the Japanese Islands which is feasible for tidal current generation are not a lot because sea sites where tidal current velocity is above 2.0 m/s are a few. We can find such sea sites at a west side of the Kyushu Island especially. However, we would earn electrical energy to be generated if it is able to generate electricity long time using around 1.0 m/s in current velocity. A vertical axis turbine should be better than horizontal axis types because VATs can take relatively higher torque. It is very useful that we can set and control a marine turbine to be higher performance in various current velocity. The present study introduce variable pitch-control system to a vertical axis turbine for tidal current generation. The pitch-control system adapts a cycloidal mechanism so that to vary pitch angle of turbine blades is conducted mechanically. The study developed a vertical axis marine turbine with cycloidal pitch-controlled three blades which was based on previous studies and experimental data. The diameter of the turbine is 1.0 m, length of a blade is 1.3 m. The turbine was set on a floating structure in order to carry out towing tests at a sea. We obtained several kinds of data from the towing tests, which were turbine torque, the number of rotation of the turbine, output power from an electrical generator and acceleration of the floating structure. As a result, the turbine made 50 W power from the generator. Although the PTO was not so large, the pitch-control was effective very much. Some issues were found at the same time. We need to consider and develop more useful gears, assemble methods to be feasible of variable pitch system.

Several types of oscillating water column (OWC) type wave energy converters (WECs) are researched and developed in the world. They are floating types and fixed types. In case of a fixed type, wave dissipating caissons could be replaced to WECs of an OWC type. On OWC types, installation of the projecting-walls (PWs) is useful in order to improve PTO performance. In this study, it was considered that a double dissipating caisson was used as an OWC type WEC with PWs. A front caisson of the double caisson seems the area surrounded by PWs and a back caisson can be seen as an OWC. The paper studied basic property of the primary conversion from wave power to power of air from model tests in a wave tank. As a result, wave height strongly effects on behaviours of OWC motion as well as air pressure. Finally, the primary conversion was affected by wave height. Besides, the concept of use of a double caisson was useful from the primary conversion over 80 % evaluated using test data.

This study investigated difference of marine turbine performance due to assembling and PTO resistance by comparing with two turbine models. A turbine targeted in the study is a vertical axis type and vertical straight blades are a variable-pitch-controlled type developed. The models are basically same but how to assemble blades and resistance to obtain turbine power are different. Model A was used for basic investigation of turbine performance. Model B was redesigned for towing tests as a sea test. A setup system using Model B had an electrical generator. The authors conducted both experiments in a water flume and the sea test using Model B. Using both two models, characteristics of turbine performance of them were discussed.

This paper describes power take-off (PTO) performance by wave energy converters (WECs) and possibility of electrical power generation in a year offshore of Japanese some coasts. A corresponding WEC system is a very large floating structure installed with many WECs of a oscillating water column (OWC) type, which are arranged along edges of the structure. The corresponding VLFS is a pontoon type so that installation in offshore sea is difficult because of large elastic motion. Because OWC type WECs harvest wave power, they also have damper function against motion of a structure. To install OWC type WECs onto a VLFS provides an electrical power base offshore and that elastic motion can be reduced by themselves.

Newly developed high-strength reaction-sintered silicon carbide is an attractive material for lightweight optical mirror with two times higher bending strength than other SiC materials. The polished surface has no pore and is suited to visible region as well as infrared without CVD SiC coating. The fabrication process, with low temperature and small shrinkage, is also suited to develop large scale objects.

Japan imports coal from Indonesia, the main coal supplier in the Asia-Pacific region. Effective and efficient movement of coal down the Markham River in East Kalimantan, Indonesia, and onto bulk carriers is challenging because the river is shallow and generally cannot accommodate bulk carriers. The primary transportation system comprises small barges that are shuttled back and forth between the inland barge ports along the river and bulk carriers offshore. This system is very time-consuming. This paper proposes a large-scale floating coal transshipment station (LFTS) for loading, storing, and offloading coal. It will act as a relay base for barges and bulk carriers. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. The proposed LFTS can store 5 times the capacity of one bulk carrier and can accommodate 2 bulk carriers at the same time during offloading. The LFTS is compartmentalized by bulkheads to segregate coal according to quality. This paper discusses LFTS static stability and its elastic deformation characteristics during coal loading operations. In this study, linear potential theory and the finite element method (FEM) were used to analyze the LFTS static hydroelastic motion. Due to the compartments, coal loading conditions can vary significantly and affect the local static deflection, so we modeled the overall deformation and rigidity under various operational scenarios. The results were compared to the allowable material stress to identify conditions that will produce material failure. Moreover, we evaluated operation in the shallow Kalimantan River, since the weight of loaded coal deepens the LFTS draft, reducing the clearance between the LFTS and sea bed. We found that this reduced clearance and large added mass impact the natural frequency of the LFTS.

The damage investigations that followed the Great East Japan Earthquake revealed that automobiles, shipping containers, and even ships themselves had been caught up in the resulting tsunami before being hurled into various port facilities, causing immense damage. The damage characteristics of such collisions must be an integral part of disaster mitigation measures aimed at reducing damage due to drifting ships. When considering the impact force of massive vessels on port facilities, it is necessary to take into account the changes in the drift velocity of the vessels due to waves reflected from the facilities and other coastal structures. In previous studies, the moving particle semi-implicit (MPS) method has been adopted to examine cascading tsunami flotsam damage by means of numerical simulations. In the present study, we use the MPS method to examine the drifting behavior and impact force of ships moored to an actual harbor, taking into account waves reflected from coastal area structures. Based on the results, we discuss the applicability of this method to disaster mitigation measures.

An innumerable number of buildings in the coastal part of the east side of Japan were devastated by the Great East Japan Earthquake and Tsunami. Medical institutions also suffered the damage caused by tsunami, and the function to carry out the medical act has been spoiled. And the disabled concentrated on the medical institution which avoided tsunami damage. Under such circumstances, assistance from the water area began three days after the earthquake disaster, and much support supplies reached the stricken area. It was revealed that the support from the water area including the river was extremely effective against the stricken area. And then, the Tokyo Inland Earthquake disaster was assumed, floating medical support system installed in the quay of Arakawa River in Tokyo was proposed. Floating medical support system is movable; furthermore, it is built in the structural system of having very high isolation characteristics. Therefore, feasibility study such as selection of suitable setting position of this floating structure on Arakawa River, floor planning and flow planning at the time of always and a disaster, facilities and storage of various material, structural strength of the floating base, and the effects of disaster risk reduction was carried out about floating medical support system.

In this study, we propose color images with color enhancement for congenital red–green color deficiency on the basis of the model proposed by Mochizuki et al. [In Terrassa, Spain: Proceedings for CGIV, Springfield VA: IST208–213] with the aim of facilitating color customization in displays used by color-deficient observers. Three types of color enhancements for deficiency were addressed in this study: colors were enhanced along the protan confusion line (i.e., P-enhancement), deutan confusion line (i.e., D-enhancement), and a line between the protan and deutan confusion lines (i.e., mix-enhancement). We investigated the color-enhanced image that is most preferred by each group of protan, deutan, and normal observers. Protan and deutan in this study indicate observers that are both dichromats and anomalous trichromats. Nine protan, nine deutan, and six normal observers participated in the experiment. The results showed that among the three types of color enhancements, the D-enhancement provided the best performance for protan observers. For deutan observers, all three types provided effective enhancement, although the P- and mix-enhancements were slightly better than the D-enhancement. Our results indicated that color enhancement increases the preference evaluations of protan and deutan observers. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 234–251, 2014; Published Online 20 February 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.21795

This paper proposes a large-scale floating coal stockyard (LFCS) and discusses its elastic behavior. Indonesia has recently become the main country supplying coal in the Asia-Pacific region. However, there is concern that export to Japan will decrease as coal demand increases. Therefore, the trend of coal transport in Indonesia is a very important matter in ensuring the continued stable import of coal to Japan. It is difficult for bulk carriers to traverse the shallow terrain of the seabed of the Markham River in East Kalimantan to reach coastal areas. Additionally, an LFCS can be operated as a relay base for barges, and large coal carriers have been proposed for use in offshore areas. The LFCS is capable of loading, storing, and offloading coal. Installing an LFCS offshore Kalimantan is expected to improve coal transport productivity in the region. Under such circumstances, the design plan proposed in this paper can simultaneously perform independent loading and unloading without interference. The partial mass distribution and local rigidity of the LFCS varies depending on the coal loading conditions. In addition, because the structure has a planar shape, the response of the LFCS showed elastic behavior. Design example of such a huge floating structure with the great difference of the displacement is unparalleled, it is very important to clarify a design fundamental subject. The objectives of this study are to provide a preliminary LFCS design and investigate the impact of varying the mass distribution and local rigidity on not only the distribution of the distortion and internal stress but also on the dynamic hydroelastic motion of the LFCS when it is impacted by waves. Therefore, the wave response of the LFCS was analyzed under different loading conditions.

While a type of marine turbine for tidal current generation can be chosen from several types, a vertical axis marine turbine (VAMT) should be better in Japan because sea areas around Japanese islands where current velocity is sufficient are limited. This study conducted a sea test of a VAMT of a floating type installed with six straight pitch-controllable blades. The cycloidal mechanism was adapted for the pitch control. The purpose of the study is to understand effects of ocean waves and motion of a floating body on turbine performance and behaviours of the VAMT in unideal current conditions. Besides, the data taken should be effective to consider that effects in order to design VAMTs. The setup with the setting angle of −30 degrees suggested highest performance from the sea tests, then 15% in maximum turbine power and maximum output was 40W. Ocean waves strongly affected on the turbine performance because fluid velocity changes due to ocean waves and it was unable to neglect the variation of the velocity in spite of small. The characteristics of the turbine sensitively varied because of ocean waves. The results suggested that during accelerating and decelerating incoming fluid speed, characteristics of the turbine were different in each case.

This paper presents a feasibility study for a floating medical support system, and describes its basic concept with regards to the installation location, its primary function and patient capacity. In 2011, Japan experienced a major catastrophe: the Great East Japan Earthquake and subsequent tsunami. After the tsunami struck, overland transport routes were cut off, and consequently emergency supplies and people requiring medical attention could not be transported very efficiently. Many hospitals and other emergency facilities were destroyed or were operating with reduced capabilities during this period, meaning victims could not receive treatment within a reasonable timeframe. Therefore, we need to consider emergency facilities, particularly for medical support, which are resilient and versatile for use in such situations. Floating bases for disaster relief and support ships are already available for deployment along coastal regions or on rivers near affected areas. A medical support floating base has also been proposed, which is called the Medi-float hereafter, in preparation for the anticipated Tokyo Inland Earthquake. The original proposal was deemed inadequate in terms of its choice of deployment area, and its maximum capacity for patients. The objectives of this paper are to decide the Medi-float’s primary function, the location where it should be installed, and to determine its capacity and a floor plan which adheres to the relevant regulations. It is determined that the primary function of the Medi-float should be as a dialysis treatment center during normal operation and primarily for the treatment of crush syndrome patients during a disaster. A location in Sumida ward is chosen for the installation area. In the floor plan, the Medi-float has 55 beds in dialysis treatment rooms. Also, there are areas of open space in the Medi-float to be used for coordinating the distribution of emergency supplies. The maximum capacity for patients is approximately 5,300 people, and the Medi-float can treat up to 130 patients with crush syndrome every 2 days. There is estimated to be around 106 patients with crush syndrome around the installation area in the event of a major earthquake. Therefore, this study clearly demonstrates the usefulness of the Medi-float.

Indonesia has recently become the world's second largest exporter of coal, and a great deal of coal is supplied to the Asia Pacific. However, there is concern that export to Japan will decrease as coal demand in Indonesia increases. The trend of coal transport in Indonesia is a very important matter in ensuring the continued stable import of coal to Japan. Therefore, this paper proposes LFTS (Large-Scale Floating Transshipment Station for Loading Coal) to improve the coal transportation productivity. The LFTS is installed in the estuarine waters of the Markham River in Indonesia's East Kalimantan, and it is capable of loading, storing, and offloading coal. The partial mass distribution and local rigidity of the LFTS varies depending on the coal loading conditions. In addition, because the structure has a planar shape, the response of the LFTS shows elastic behavior. Design example of such a huge floating structure with the great difference of the displacement is unparalleled, it is very important to clarify a design fundamental subject. Therefore, in this paper, a preliminary LFTS design is provided, and it's characteristics in terms of stress and stability in static, and dynamic hydroelastic motion under various coal loading condition is investigated.

Several types of oscillating water column (OWC) type wave energy converters (WECs) are researched and developed in the world. They are floating types and fixed types. In case of a fixed type, wave dissipating caissons could be replaced to WECs of an OWC type. On OWC types, installation of the projecting-walls (PWs) is useful in order to improve PTO performance. In this study, it was considered that a double dissipating caisson was used as an OWC type WEC with PWs. A front caisson of the double caisson seems the area surrounded by PWs and a back caisson can be seen as an OWC. The paper studied basic property of the primary conversion from wave power to power of air with model tests in a wave tank. As a result, wave height strongly effects on behaviors of OWC motion as well as air pressure. Finally, the primary conversion and PTO performance was affected by wave height. Besides, the concept of use of a double caisson was useful from PTO performance estimated.

Collision phenomena of drifting ship caused by tsunami are one of the major challenges on design of coastal structure. Here, FEMA[1] is recommended a calculation formula of collision force which is validated by the water tank experiment. And it is indicated its availability. However, the FEMA's formula has not considered about collision phenomena of huge ships. Then, the objective of the present study is to examine the MPS IEB's relationship with the FEMA's formula using three-dimensional particle simulation. In addition, this paper assesses the applicability of the model which is installed the non-linearity stiffness, and discusses difference of the result from the MPS-IEB. As these results, we found out knowledges which is the FEMA's formula overvalues a dimensionless collision force than the result of the MPS-IEB. The value was approximately 30.0%. Therefore, it is necessary to verify a characteristic of a behavior of an object including drift speed if you estimate collision force of a large ship using the FEMA's formula. On the other hand, we made a proposal of the MPS-IPB and conducted a simplified simulation. The displacement of the MPS-IPB is indicates an upward trend more than the previous model. The reason is due to the influence of difference of the structural stiffness which is object displacement.

The color gamut of xvYCC is wider than that of film. We evaluated the color reproduction and developed a new method of converting the video signal, which reproduced color of a film in xvYCC color space faithfully.

An innumerable number of buildings in the coastal part of the east side of Japan were devastated by the Great East Japan Earthquake and Tsunami. Medical institutions also suffered the damage caused by tsunami, and the function to carry out the medical act has been spoiled. And the disabled concentrated on the medical institution which avoided tsunami damage. Under such circumstances, assistance from the water area began three days after the earthquake disaster, and much support supplies reached the stricken area. It was revealed that the support from the water area including the river was extremely effective against the stricken area. And then, the Tokyo Inland Earthquake disaster was assumed, floating medical support system (hereafter, Medi-Float) installed in the quay of Arakawa River in Tokyo was proposed. Medi-Float is movable; furthermore, it is built in the structural system of having very high isolation characteristics. The float proposed in this study is a facility based on a completely new concept and hence it is difficult to get approval as simply a hardware structure or facility, even if it is safe. Our study considers the constraints with respect to installing the system on the river as the basic plan of the specific Medi-Float. It takes into account the floor planning and flow planning based on operational methods, considers scale planning and weight calculation and the structural strength of the float foundation. The study conducts basic plan of the feasibility of the first-of-its-kind medical float as a marine structure. As the next step, the research on dynamic behavior of Medi-Float will be started, and the validity of this design is verified, technical issues in the design of the Medi-Float should be clarified.Copyright © 2015 by ASME

Wave energy convertors (WEC) of oscillating water column (OWC) types make compressed air due to vertical movement of a part of water column, which are surrounded by some walls in water. As a result, the compressed air works to rotate an air turbine which also works for an electrical generator. If a structural system can make to move water such like a water column, a shape of a structure would not matter. Wave dissipating caissons installed in or on the existing production line can make to transfer a water wave to a flow and to reduce wave energy by making to overflow them. The caissons which can be overflowed by the water would actuate a water region vertically such like an oscillating water column system. This study investigated if we can utilize wave dissipating caissons as a WEC. Wave dissipating caissons also decrease wave energy due to passing through themselves. Even so, when an air turbine can be installed onto the caisson in order to harvest wave energy, it would be possible to produce electricity at low cost. The study conducted model experiments using the model assumed that wave dissipating double-caissons were remodelled to OWC type WECs with side walls and evaluated performance of the primary conversion of them. In addition, effects of how to arrange the number of the WECs on the primary conversion efficiency were investigated with theoretical calculations based on the linear potential theory and the possibility of utilization of wave dissipating caissons as a WEC was examined in the study.

Lightweight mirrors of SiC (Silicon Carbide) are currently used for numerous space telescopes. The most favorable characteristics of the material are high specific stiffness, high thermal conductivity and low thermal expansion (CTE). For large-scale SiC mirrors, however, the machining cost is very high using traditional polishing process. In this study, a large-scale SiC spherical mirror (φ360mm) was designed as reducing-weight structure with many open-back triangular cells. The ELID mirror grinding technique was conducted to finish the mirror. A unique jig composed of many hydrostatic actuators was developed for reducing the deformation resulted from the grinding force. By using an on-machine measurement system, the form error of the finished surface was measured. The surface roughness of the mirror was also examined with a mobile AFM. As result, a high quality mirror surface, which has form accuracy 0.8µm P-V and roughness of Ra 7.8nm, was achieved. This paper presents the experimental procedure and results.

The high-strength reaction-sintered silicon carbide (RS-SiC) developed by TOSHIBA is one of the most excellent materials for large-scale space-borne optics. The bending strength of the high-strength RS-SiC is two times higher than other SiC ceramics. The purpose of this study is to investigate the ELID grinding properties of the high strength RS-SiC. Two types of metal bond diamond wheels (cup type and straight type) were used to grinding tests. The ground surface properties, such as roughness, subsurface damage and micro-step were made clear by measurement or observation. It was confirmed that, both the surface roughness and the depth of micro-step produced by cup-wheel were lower than those produced by straight-wheel. When a #20000 grit sized cup-wheel was used, a considerably high quality mirror surface (Ra

In the development of large-scale astronomical telescopes, certain new ceramics such as Silicon Carbides (SiC) and glass-ceramics (Zerodur) are applied for primary mirrors. However, the surface finishing of these ceramic mirrors is very time consuming by traditional polishing processes. In this study, a highly efficient process called ELID (Electrolytic In-process Dressing) grinding was conducted to grind ceramics for lightweight mirrors (CVD-SiC, Sintered-SiC, Zerodur). The dependence of subsurface properties on grinding process parameters was investigated. The subsurface damages on the ground surfaces were observed by AFM. The results demonstrated that crack-free surface could be obtained for CVD-SiC and Zerodur using cast iron bond diamond wheel with grain size of 4µm. The total depth of cut needed was found to be between 13 and 20µm. It was difficult to eliminate the subsurface damages generated on the ground surface of Sintered SiC, even though the depth of cut was as small as 0.1µm.