• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.89-96
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• 2012

Based on the hydroelastic theory and the matched eigenfunction expansion method(MEEM), the dynamic behavior of the porous flexible net sheet and wave forces have been investigated in monochromatic waves. The net sheet is installed vertically with the submergence depth. Top end of a net sheet is fixed and its lower end is attached by a clump weight. It is assumed that the initial tension is sufficiently large so that the effects of dynamictension variation can be neglected. The boundary condition on the porous flexible net sheet is derived based on Darcy's fine-pore model and body boundary condition. The developed analytic model can be extended to the impermeable/permeable vertical plate and the impermeable flexible membrane. The analytical model was used to study the influence of design parameters(wave characteristics, porosity, submergence depth, initial tension) on the response characteristics and wave load of the net sheet.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.1
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• pp.60-64
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• 1999

Recently, for the reconstruction of bony defect and cosmetic improvement, many graft materials and implants have been widely used in the various surgical situations. The alloplastic materials have many advantages such as simplicity of operation, no additional need of surgery, and easy manipulation. The $Medpor^{TM}$(porous high-density polyethylene, Porex Co., USA) was initially studied in 1972 for surgical implant and introduced as an implant material for oral and maxillofacial region by Sauer and King in 1988. This material permits full ingrowth of bone into the implants, substantially increasing the implant's incorporation into the recipient site. It can be shaved during the surgery, which results in an improvement and prefabricated various size and shapes to fit into the surgical defect. The $Medpor^{TM}$ was used in 32 patients from 1995 to 1997 at the maxillofacial region. It was used for paranasal augmentation in 24 cases, for malar augmentation in 2 cases, for infraorbital augmentation in 2 cases, for mandibular angle augmentation in 2 cases, for mandibular body augmentation in 2 cases, for chin vertical augmentation in 1 case. It was mainly fixed with miniplate or screw. There were few complications except one infection and one exposure of the implant.

• Steel and Composite Structures
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• v.50 no.2
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• pp.201-216
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• 2024

This paper is motivated by the lack of studies relating to vibration and nonlinear resonance of fluid-conveying cantilever porous GPLR pipes with fractional viscoelastic model resting on nonlinear foundations. A dynamical model of cantilever porous Graphene Platelet Reinforced (GPLR) pipes conveying fluid and resting on nonlinear foundation is proposed, and the vibration, natural frequencies and primary resonant of such system are explored. The pipe body is considered to be composed of GPLR viscoelastic polymeric pipe with porosity in which Halpin-Tsai scheme in conjunction with fractional viscoelastic model is used to govern the construction relation of the nanocomposite pipe. Three different porosity distributions through the pipe thickness are introduced. The harmonic concentrated force is also applied on pipe and excitation frequency is close to the first natural frequency. The governing equation for transverse motion of the pipe is derived by the Hamilton principle and then discretized by the Galerkin procedure. In order to obtain the frequency-response equation, the differential equation is solved with the assumption of small displacement, damping coefficient, and excitation amplitude by the multiple scale method. A parametric sensitivity analysis is carried out to reveal the influence of different parameters, such as nanocomposite pipe properties, fluid velocity and nonlinear viscoelastic foundation coefficients, on the primary resonance and linear natural frequency. Results indicate that the GPLs weight fraction porosity coefficient, fractional derivative order and the retardation time have substantial influences on the dynamic response of the system.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.363-368
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• 2012

Nitriding and post-sintering behavior of powder mixture compacts were investigated. As mixture compacts are different from simple Si compacts, the fabrication of a sintered body with a mixture composition has engineering implications. In this research, in specimens without a pore former, the extent of nitridation increased with $Si_3N_4$ content, while the highest extent of nitridation was measured in $Si_3N_4$-free composition when a pore former was added. Large pores made from the thermal decomposition of the pore former collapsed, and they were filled with a reaction product, reaction-bonded silicon nitride (RBSN) in the $Si_3N_4$-free specimen. On the other hand, pores from the decomposed pore former were retained in the $Si_3N_4$-added specimen. Introduction of small $Si_3N_4$ particles ($d_{50}=0.3{\mu}m$) into a powder compact consisting of large silicon particles ($d_{50}=7{\mu}m$) promoted close packing in the green body compact, and resulted in a stable strut structure after decomposition of the pore former. The local packing density of the strut structure depends on silicon to $Si_3N_4$ size ratio and affected both nitriding reaction kinetics and microstructure in the post-sintered body.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.1
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• pp.51-62
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• 2014

The purpose of this experiment was to evaluate the apatite-formation abilities of low-modulus Ti-7.5Mo substrates treated with NaOH aqueous solutions and subsequent ethyl alcohol aging before soaking them in simulated body fluid. Specimens of Ti-7.5Mo were initially treated with 5 M NaOH at $60^{\circ}C$ for 24 h, resulting in the formation of a porous network structure composed of sodium hydrogen titanate. Afterwards, the specimens were aged in ethyl alcohol at $60^{\circ}C$ for 5 or 10 min, and subsequently immersed in simulated body fluid at $37^{\circ}C$ for 3, 7 and 14 days. Ethyl alcohol aging significantly increased the apatite-forming abilities of Ti-7.5Mo. The amount of apatite deposited on the Ti-7.5Mo after NaOH treatment and subsequent ethyl alcohol aging was much greater, especially after the Ti-7.5Mo specimens were aged for 5 min. Due to its excellent combination of bioactivity, low elastic modulus and low processing costs, the Ti-7.5Mo treated with NaOH aqueous solutions and subsequently aged in ethyl alcohol has promising heavy load-bearing applications.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• Journal of Korean Philosophical Society
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• no.123
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• pp.137-185
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• 2018

This article aims to deconstruct the mechanism of male domination that constantly reproduces the hegemonic class of men. In order to overcome misogyny, we should no longer deny the ontological dimension of the reality of women's oppressions and the pre-eminence of the material condition of women's existence. In addition, the possibility of the category of women as a modality of resistance should be taken into consideration. First, I will highlight the correlation between penis and phallus according to which the phallus refers to the penis which is malleable and fragile and which disappears without being castrated by the external factor. From here we could deduce the fragility and imperfection, the non-absoluteness of the phallic order. Secondly, I will analyze the mechanism of penis-narcissism, which is the modality of the constitution of the individual identity of man. The penis is not only a physiological organ, but a site of self-estimation and the validity of the succession of power and authority of the father's law. With this penis-narcissism, man is constituted as a hegemonic body that can let itself go without worrying about the reactions of others. Thirdly, I will focus on the mechanism of the penis-cartel which is the modality of the formation of the collective identity. The penis-cartel is reinforced by the mutual affirmation of the superiority of men among themselves, but also by the permission and the tacit agreement of their absurdity and lack of rationality and corruption. Because the privilege of men is not monopolized by a small part of the elite, but is consciously and unconsciously shared by all men who are part of the hegemonic and collective category. In order to deconstruct the penis-narcissism and the penis-cartel, it is necessary to demonstrate that the penis is not a self-sufficient body, nor a closed and impermeable body, but that it is a porous body where the organ serves both ejaculation and urinary ejection. The penis is a porous body that is at once the site of sublimity and degradation, purity and impurity. In addition, the penis is no longer an all-powerful and aggressive organ, but it is a malleable and fluid flesh that constantly changes its shape. Linked to a phallus-organ that is the notion of Jacques-Alain Miller, it is a site of deficiency and vulnerability that is not the axis of the penis-cartel. It is through the notion of the double porosity of the penis and the phenomenology of the flesh of the penis, I try to provide the modality of undoing the reproductive mechanism of predatory masculinity. Because this would be an effective strategy to overcome misogyny.

• Journal of fish pathology
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• v.28 no.2
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• pp.79-85
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• 2015

A specimen of porous-head eelpout Bothrocara hollandi (Zoarcidae: Perciformes) caught from the East Sea was found to harbour a myxosporean parasite. Numerous whitish pseudocysts were scattered throughout the body musculature of this individual specimen. Fresh myxosporean spores were found from the squashed pseudocysts under light microscopy. They were subspherical in frontal view with a length of $11.9(11.0{\sim}13.5){\mu}m$, width of $11.6(10.7{\sim}13.6){\mu}m$, and thickness of $7.8(6.9{\sim}8.8){\mu}m$. Two polar capsules were almost equally pyriform with a length of $4.4(3.2{\sim}5.3){\mu}m$ and width of $3.3(2.4{\sim}4.2){\mu}m$. Morphometric and host ecology analysis revealed that this myxosporean parasite could be identified as Myxobolus aeglefini Auerbach 1906. Phylogenetic analysis based on 18S rDNA sequences also revealed that M. aeglefini was clustered with M. albi and M. groenlandicus in the same branch, sharing 97.7% and 96.9% sequence similarities with M. albi and M. groenlandicus, respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.578-586
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• 2005

Air mattress is now used widely to prevent the pressure ulcer by reducing the localized pressure peaks. The pressure control method based on the anthrophometric model of an air-cell mattress developed in this study is presented. The air-cell mattress has 18 cylindrical air cells made of porous material allowing air leakage. Even though the air leakage can contribute to reducing the development of pressure ulcer by lowering the pressure peak, temperature and humidity, the air pressure changes with time and the desired air-cell pressure has to be determined as an optimal value for each user. To select the desired air-cell pressure, we first divide the parts of the body into four sections such as head, trunk, hip, and leg. Then, the pressure of each section grouped with air-cells is calculated from the weight of each part estimated from the individual height and body weight. Air supply system for the air-cell mattress is implemented by using four electronic solenoid valves and an air compressor, and it is driven by a real-time microcontroller. We experimented with five subjects of the contact pressure on skin. The experimental results show that the proposed air-cell mattress is effective for the prevention of the pressure ulcer.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.1-4
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• 2004

On the background of general idea and technique of bioscience, medicine and engineering, tissue engineering aim at maintenance, improvement and repair of human body function through manufacturing and transplantation of artificial tissue and organ exchangeable human body. Basic material used in the area is scaffold that aid tissue and organ formation. Making scaffold, solvent-casting and particulate leaching technique is widely used in manufacturing of porous polymer scaffold. There are many types of particle including salt and gelatin. Salt is a most commonly used particulate because it is easily available and very easy to handle and gelatin particle is another candidate for this method because it is known as a material, which enhances cell attachment and proliferation. But there is no comparative study of two kinds of materials. In this study we compared the biocompatibility of the two scaffolds made from salt(salt scaffold) and gelatin particle (gelatin scaffold). These results demonstrated that gelatin scaffold showed better attachment of cells at the initial stage and better proliferation of cells. The better performance of gelatin scaffold is contributed to the better connection of pores in the same porosity.