A Fundamental Study on Motion Characteristics of the Large-Scale Floating Coal Transshipment Station by Elastic Mooring Lines

2021 ◽  
Author(s):  
Hiroaki Eto ◽  
Ryo Sekiguchi ◽  
Hitomi Kashima ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
...  
Keyword(s):  
Large Scale ◽  
Mooring Lines ◽  
Fundamental Study ◽  
Motion Characteristics

A Fundamental Study on Motion Characteristics of the Large-Scale Floating Coal Transshipment Station by Elastic Mooring Lines

2020 ◽  
Author(s):  
Hiroaki Eto ◽  
Ryo Sekiguchi ◽  
Hitomi Kashima ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
...  
Keyword(s):  
Large Scale ◽  
Line Tension ◽  
Asia Pacific ◽  
Floating Body ◽  
Mooring Line ◽  
Mooring System ◽  
Mooring Lines ◽  
Fundamental Study ◽  
Bulk Carriers ◽  
Motion Characteristics

Abstract 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.

A Fundamental Study on the Optimal Design of the Floating Tsunami Protection Wharf: About the Floating Body Length

2017 ◽  
Author(s):  
Mitsuhiro Masuda ◽  
Kiyokazu Minami ◽  
Koichi Masuda
Keyword(s):  
Numerical Simulation ◽  
Body Length ◽  
Large Scale ◽  
Mitigation Measures ◽  
Floating Body ◽  
Disaster Prevention ◽  
Mooring Lines ◽  
Fundamental Study ◽  
Tsunami Disaster ◽  
Floating Pier

On the vessels moored at the wharf, the situation such as drifting and wash up on the wharf due to the breaking of the mooring lines is occurred by the tsunami. The authors are clarified for applicability of the proposed floating tsunami protection wharf (FTPW). FTPW is the floating pier for tsunami disaster. The effect of FTPW is most promising as disaster prevention and mitigation measures for the moored vessels. The authors examined large scale FTPW until now. However, when floating body length was longer than a ship breadth, the possibility that disaster prevention performance of FTPW decreased was confirmed. In this study, the examination about the influence that floating body length gives in disaster prevention performance of FTPW is performed using numerical simulation. Therefore, in the range of length of FTPW/breadth of vessel = 1.0 to 8.0, it was confirmed that tsunami protection performance of FTPW was shown enough.

Fundamental study on clarification of brain molecular pathology of Nasu-Hakola disease

Impact ◽  
2019 ◽  
Vol 2019 (8) ◽  
pp. 24-26
Author(s):  
Jun-ichi Satoh
Keyword(s):  
Multiple Sclerosis ◽  
Human Brain ◽  
Clinical Research ◽  
Neurodegenerative Diseases ◽  
Molecular Pathology ◽  
Large Scale ◽  
Molecular Pathogenesis ◽  
Novel Therapies ◽  
Brain Pathology ◽  
Fundamental Study

Brain pathology expert Dr Jun-ichi Satoh, from the Department of Bioinformatics and Molecular Neuropathology of Meiji Pharmaceutical University in Tokyo, is drawing on his expertise on neurology and neuroimmunology to delve into some of the more complex diseases impacting the human brain. His knowledge and expertise have allowed him to direct his research interests to study neurodegenerative diseases, such as Alzheimer's disease (AD), and neuroinflammatory diseases, such as multiple sclerosis (MS), and the analysis of their molecular pathogenesis by using a bioinformatics approach. His current focus is on Nasu-Hakola disease (NHD), a disease whose rarity has posed significant barriers towards performing large-scale clinical research in order to understand what exactly causes this disease and develop effective novel therapies.

Research on Motion Characteristics and Formation Mechanism of Debris Flow

2014 ◽  
Vol 711 ◽  
pp. 388-391
Author(s):  
Ji Wei Xu ◽  
Ming Dong Zhang ◽  
Mao Sheng Zhang
Keyword(s):  
Debris Flow ◽  
Formation Mechanism ◽  
Debris Flows ◽  
Catchment Area ◽  
Large Scale ◽  
Large Range ◽  
Extreme Rainfall ◽  
Small Catchment ◽  
Rainfall Characteristics ◽  
Motion Characteristics

On July 9 2013, debris flows occurred around Longchi town with large scale and wide harm, which was a great threat to people's life and property as well as reconstruction work. Debris flow ditch in the surrounding town was studied. This paper focused on loose materials, topography and rainfall characteristics, and explored the formation mechanism of debris flow in Longchi town. The result shows that: a small catchment area in valleys also have the risk of large range of accumulation of debris flow, the debris flow is caused by a lot of loose materials in mountains after earthquake and extreme rainfall. Research results contribute to a better understanding of trigger condition of debris flow after earthquake.

Effects of Seismic Incident Directionality on Ground Motion Characteristics and Responses of a Single-Mass Bi-Degree-of-Freedom System

2021 ◽  
pp. 2150119
Author(s):  
Jun Gong ◽  
Xudong Zhi ◽  
Feng Fan ◽  
Shizhao Shen ◽  
Da Qaio ◽  
...  
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Propagation Distance ◽  
Degree Of Freedom ◽  
Different Types ◽  
Single Mass ◽  
Motion Characteristics ◽  
The Impact

To investigate the variability of ground motion characteristics (GMC) with the angle of seismic incidence (ASI) and the impact of seismic incident directionality on structural responses, first, a large-scale database of recorded ground motions was used to analyze the causes of GMC variability due to the seismic incident directionality effect (SIDE). Then a single-mass bi-degree-of-freedom system (SM-BDOF-S) with different types of symmetrical sections was selected to explore the influence mechanism of SIDE on the seismic responses. The results illustrated that the GMC has substantial variability with the ASI, which is independent of the earthquake source, propagation distance, and site condition, and exhibits complex random characteristics. Additionally, a classification method for ground motions is proposed based on this GMC variability to establish a criterion for selecting ground motions in seismic analysis considering the SIDE. Moreover, for an SM-BDOF-S, the response spectral plane is proposed to explain the transition behavior of spectral responses that are very similar among different stiffness ratios, but divergent for different types of ground motions. The influence of SIDE on structures is determined by their stiffness and stiffness ratio in the [Formula: see text]- and [Formula: see text]-directions, as well as the type of ground motion.

Fundamental Study on Elastic Behavior of Large-Scale Floating Coal Stockyard

2016 ◽  
Author(s):  
Hiroaki Eto ◽  
Chiaki Sato ◽  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Tomoyuki Kishida ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Large Scale ◽  
Asia Pacific ◽  
Elastic Behavior ◽  
Loading Conditions ◽  
Floating Structure ◽  
Fundamental Study ◽  
Local Rigidity ◽  
East Kalimantan ◽  
The Impact

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.

Experimental Study on a Motion of “Underwater Platform” Including Hydro-Elastic Deformation in Waves

2015 ◽  
Author(s):  
Motohiko Murai ◽  
Ken Haneda ◽  
Jun Yamanoi ◽  
Yuta Abe
Keyword(s):  
Numerical Simulations ◽  
Elastic Deformation ◽  
Large Scale ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Condition ◽  
Small Motion ◽  
Small Water ◽  
Motion Characteristics ◽  
Plane Area

A new type of floater for floating offshore wind turbine (FOWT) was proposed. The floater, named an “underwater platform”, aims at high economic efficiency of energy generation of floating wind farm. The underwater platform is a large scale submerged structure which has small water plane area and can support several wind turbines. It is expected that the platform has small motion characteristics in waves because of its small water plane area, and it contributes for FOWT to generate energy safety. In this study, the feasibility and usefulness study about the platform was carried out through experiments and numerical simulations. The first experiment was conducted with partial rigid model of the platform to verify the feasibility. From the experiment, it was confirmed that the model has small motion characteristics in waves. The experimental results were compared with numerical simulations of potential theory and they were well matched. Besides, the coupling analysis with aero-hydro dynamics was also carried out and it was confirmed that the stability of the platform was enough in steady wind condition. The second experiment was conducted with elastic body model to study the elastic deformation of the platform in waves. From the experiment, it was confirmed that the deformation is small when the draft was 250mm (50m in the actual model).

A Fundamental Study on Collision of a Tsunami Drifting Objects Against Structures Using MPS Method and FEM

2018 ◽  
Author(s):  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Daichi Murata ◽  
Hiroaki Eto ◽  
Akihiro Matsuoka ◽  
...  
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Steel Structure ◽  
Simulation Method ◽  
Coastal Areas ◽  
Numerical Calculations ◽  
Fundamental Study ◽  
Mps Method ◽  
Acrylic Plate ◽  
The Impact

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.

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