• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.294-300
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• 2002

In this study, we fabricated thermopile infrared sensor with floating membrane structure. Floating membrane was formed by SOI(Silicon On Insulator) structure. In SOI structure, silicon dioxide layer between top silicon layer and bottom silicon substrate was etched by HF solution, then membrane was floated over substrate. After membrane was floated, thermopile pattern was formed on membrane. By insertion of SOI technology, we could obtain thermal isolation structure easily and passivation process for sensor pattern protection was not required during fabrication process. Then, the amplifier circuit for thermopile sensor was fabricated by using $1.5{\mu}m$ CMOS process. The voltage gain of fabricated amplifier was about two hundred.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.32-37
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• 2009

An analytic similarity shape solution was studied for a two-dimensional floating and fluid-filled membrane structure. The static shape of a membrane structure can be expressed as a set of nonlinear ordinary differential equations. The integration of curvature leads to an analytic solution for the shape, which contains unknown boundary values. Matching the upper and lower shapes at the free surface incorporated with their buoyancy allowed the unknowns to be determined. Some characteristic values of similarity shapes were evaluated and shapes are illustrated for various density ratios and volume efficiency ratios.

• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.19-28
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• 2005

The present paper outlines the numerical investigation of the incident wave interactions with fully submerged and floating dual double hull pontoon/vertical porous membrane breakwaters. Two dimensional five fluid-domains hydro-elastic formulation was carried out in the context of linear wave body interaction theory to study the wave interaction with the double hull of pontoon-membranes. The submerged circular pontoon is consisted of double hulls, which is filled with water in the void space between the outer structure and inner solid buoyant structure. Hydrodynamic characteristics of the proposed system with dual floating double-hull-pontoons filled with water have been studied numerically for the various incident waves. This study is a beginning stage research for the dual double hull porous pontoons/vertical porous membranes breakwaters which is ideally designed in order to suppress significantly the transmitted and reflected waves simultaneously.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.11-21
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• 2001

The focus of this paper is on the numerical investigation of obliquely incident wav interactions with a system composed of fully submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing between two systems. The fully submerged two systems allow surface and bottom gaps to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of the second kind) that satisfy the Helmholz governing equation in fluid domains. A boundary element program for three fluid domains based on a discrete membrane dynamic model and simple source distribution method is developed. Using this developed computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, gaps, spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters can, if it is properly tuned to the coming waves, have good performances in reflecting the obliquely incident waves over a wide range of wave frequency and headings.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.22-32
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• 2001

The numerical investigation of obliquely incident wave interactions with fully submerged dual buoy/porous-membrane floating breakwaters placed in parallel with spacing is studied based on linear potential theory and Darcy's law. The numerical solutions are obtained by using a discrete-membrane dynamic model and second-kind modified Bessel function distribution over the entire boundaries of fluid regions. First, numerical solutions for an idealized dual submerged system without buoys are obtained. Second, a more practical dual submerged system with membrane tension provided by buoys at its tops is investigated by the multi-domain boundary element method particularly devised for dual buoy/porous-membrane problems with gaps. The velocity potentials of wave motion are coupled with porous-membrane deformation, and solved simultaneously since the boundary condition on porous-membrane is not known in advance. The effects of varying permeability on membranes and wave characteristics are discussed for the optimum design parameters of systems previously studied. The inclusion of permeability on membrane eliminates the resonances that aggravate the breakwater performance. The system is highly efficient when waves generated by the buoys and membranes were mutually canceled and its energy at resonance frequency dissipates through fine pores on membranes.

• Ocean Systems Engineering
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• v.9 no.4
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• pp.409-422
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• 2019

Sloshing is a phenomenon which may lead to dynamic stability and damages on the local structure of the tank. Hence, several anti-sloshing devices are introduced in order to reduce the impact pressure and free surface elevation of liquid. A fixed baffle is the most prevailing anti-sloshing mechanism compared to the other methods. However, the additional of the baffle as the internal structure of the LNG tank can lead to frequent damages in long-term usage as this structure absorbs the sloshing loads and thus increases the maintenance cost and downtime. In this paper, a novel type of floating baffle is proposed to suppress the sloshing effect in LNG tank without the need for reconstructing the tank. The sloshing phenomenon in a membrane type LNG tank model was excited under sway motion with 30% and 50% filling condition in the model test. A regular motion by a linear actuator was applied to the tank model at different amplitudes and constant period at 1.1 seconds. Three pressure sensors were installed on the tank wall to measure the impact pressure, and a high-speed camera was utilized to record the sloshing motion. The floater baffle was modeled on the basis of uniform-discretization of domain and tested based on parametric variations. Data of pressure sensors were collected for cases without- and with-floating baffle. The results indicated successful reduction of surface run-up and impulsive pressure by using a floating baffle. The findings are expected to bring significant impacts towards safer sea transportation of LNG.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.342-347
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• 2015

Floating LNG is a new concept which is used as LNG regasification/receiving facility and for LNG production/export facility. LNG Floating Production Storage and Offloading(FPSO) concept will put vitality into marginal gas fields which were delayed because of excessive investment cost in the world. LNG Floating Storage Regasification Unit(FSRU) also provides commercially competitive and effective solutions to the areas where onshore infrastructure is not well established. LNG cargo containment system is one of the key functions for FLNG to store produced LNG on a floating structure. This paper presents a new technology related to a LNG containment system; a combined cargo containment system utilizing the advantages of iIndependent tank type and membrane system. Technical advantages have been validated through research work.

• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.39-42
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• 2019

We report on the design of oil-water separators and the selection of materials for the effective application of highly selective membranes fabricated by commercial PET (polyester) fabrics. The waterproof ability of PET fabrics was optimized to improve the separation selectivity. The density of individual PET fabrics should be over $60g/m^2$, and the multi-layered structure is more favorable for the waterproof ability together with maintaining the removal efficiency. For the continuous adsorption and removal process, the rotating perforated cylinder was selected, and covered with membranes. Furthermore, more improved and stable removal efficiency was obtained by installing floating baffles which forces the oil content to move toward membranes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.802-807
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• 2002

This study was conducted to see effects of dietary bacterial fiber produced by Gluconoucetobacter hansenii on gross structure, and disaccharidase activities of small intestine and body lipid status in rats. Bacterial fiber was prepared by drying and alkali treatment of floating membrane produced IS days after the bacterial culture using coconut juice media. Male Sprague-Dawely rats of 320+10 g were grouped into three and fed 0.5% (w/w) cholesterol diets with three different dietary fibers, i .e. cellulose, and pectin and bacterial fiber, at the level of 2% (w/w). During four-week experimental period, food intakes and body weight gains were not different among three groups. Total lengths and jejunal fragment weights of small intestine did not differ among the three groups but cecal weight was higher in bacterial fiber groups than those of the other two groups. Colon content and fecal dry weight were lower in bacterial fiber group. Sucrase activity of the jejunal mucosa was lower in bacterial fiber group but maltase activity was not different from those of the other two groups. Plasma total cholesterol level was lower and that of HDL-cholesterol higher in pectin group than those of cellulose and bacterial fiber groups, the latter of which did not differ. Both in plasma and liver triglyceride levels were lower in bacterial fiber group than cellulose and pectin groups, and liver cholesterol level was lower in pectin group. Relative liver weights and Plasma activities of GOT md GPT were not different among three groups. It is concluded that bacterial fiber used in the present study had hypotriglyceridemic effect that help improve lipid status in the body.