• Archives of Craniofacial Surgery
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• v.20 no.1
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• pp.3-9
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• 2019

Facial nerve palsy has an effect on a person's well-being functionally and psychologically. Therefore, comprehensive patient management is essential. One of the most common uncomfortable and potentially debilitating features is associated with the incapacity for eye closure. Restoration of eye closure is a key consideration during the surgical management of facial palsy. In this article, we introduce simple surgical methods-which are relatively easy to learn and involve the upper and lower eyelids-for achieving eye closure. Correcting upper eyelid function involves facilitating the component of eye closure that is in the same direction as gravity and is, therefore, less complicated and favorable outcomes than correction of lower lid. Aesthetic aspects should be considered to correct the asymmetry caused by facial palsy. Lower eyelid function involves a force that opposes gravity for eye closure, which makes correction of lower eyelid ectropion more challenging than surgery for the upper eyelid, particularly in terms of effecting a sustained correction. Initially, proper ophthalmic evaluation is required, including identifying the chronicity and severity of ectropion. Also, it is important to determine whether or not lateral canthoplasty is necessary. The lateral tarsal strip procedure is commonly used for lower lid correction. However, effective lower lid correction can be achieved with better cosmesis when extensive supporting techniques are applied, including those involving cheek tissue.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.131-143
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• 2019

In this study, the nonlinear vibration analysis of the composite nanoplate is studied. The composite nanoplate is fabricated by the functional graded (FG) core and lipid face sheets. The material properties in the FG core vary in three directions. The Kelvin-Voigt model is used to study the viscoelastic effect of the lipid layers. By using the Von-Karman assumptions, the nonlinear differential equation of the vibration analysis of the composite nanoplate is obtained. The foundation of the system is modeled by the nonlinear Pasternak foundation. The Bubnov-Galerkin method and the multiple scale method are used to solve the nonlinear differential equation of the composite nanoplate. The free and force vibration analysis of the composite nanoplate are studied. A comparison between the presented results and the reported results is done and good achievement is obtained. The reported results are verified by the results which are obtained by the Runge-Kutta method. The effects of different parameters on the nonlinear vibration frequencies, the primary, the super harmonic and subharmonic resonance cases are investigated. This work will be useful to design the nanosensors with high biocompatibility.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.31-38
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• 2021

In this paper, we proposed an optimal design for determining the shape of a lifting lug freely by applying a multivariate function to the D-type lug, which is commonly used in shipyards. We derived the optimal aspect ratio of the lug through structural analysis and analyzed the safety and behavior of the lug aspect ratio. As a result, two types of final candidates, both lighter than the existing lug weight, were suitable for the ratio. They were found to have the greatest force at an angle of 45 degrees when a load of 100 tons was imposed. When the horizontal and vertical feature ratio of the lug was 1:3, it showed excellent results in terms of safety rates while maintaining weight reduction and functional aspects.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.531-540
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• 2020

The whirl and generated forces of rotating cylinders with different diameters placed in still water and in flow are studied experimentally. For the rotating cylinders in still water, the Same Frequency Whirl (SFW) and Different Frequency Whirl (DFW) have been identified and illustrated. The corresponding SFW and DFW areas are divided. The Root Mean Square (RMS) values of the generated force coefficient dramatically increase in the defined ranges of Resonance I and Resonance II. For the rotating cylinders in flow, the hydrodynamics, SFW and DFW are illustrated. The hydrodynamic, SFW and DFW areas are divided. The RMS values of the generated forces in the range of Resonance II are much smaller than those in still water due to the generated lift forces. The discussion suggests that the frequency of the DFW may equal multiple times or one-multiple times that of the rotating frequency: the whirl direction of the DFW with multiple times the frequency of the rotating frequency is the same as the rotating direction. The whirl direction of the DFW with one-multiple times frequency of the rotating frequency is opposite to the rotating direction.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.396-406
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• 2018

In this study, a polydioxanone (PDO) and poly(L-lactic acid) (PLLA) sheath-core biphasic monofilament was designed to develop an esophageal stent with improved mechanical properties and controlled biodegradability. The radial force of PDO/PLLA sheath-core stent was 10.24 N, while that of PDO stent was 5.64 N. Deteriorations of tensile strength, elastic modulus and elongation during degradation test were also delayed on PDO/PLLA group. Hyaluronic acid-dopamine conjugate and $BaSO_4/PDO$ conjugate coating layers provided improved tissue adhesion strength and reasonable X-ray contrast, respectively. Taken all together, the sheath-core filaments with tissue adhesive and radiopaque properties will be useful in designing esophageal stents.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2915-2923
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• 2022

There is an increasing interest in passive safety systems to minimize the need for operator intervention or external power sources in nuclear power plants. Because a passive system has a weak driving force, there is greater uncertainty in the performance compared with an active system. In previous studies, several methods have been suggested to evaluate passive system reliability, and many of them estimated the failure probability using thermal-hydraulic analyses and the Monte Carlo method. However, if the functional failure of a passive system is rare, it is difficult to estimate the failure probability using conventional methods owing to their high computational time. In this paper, a procedure for the application of the Chernoff bound to the evaluation of passive system reliability is proposed. A feasibility study of the procedure was conducted on a passive decay heat removal system of a micro modular reactor in its conceptual design phase, and it was demonstrated that the passive system reliability can be evaluated without performing a large number of thermal-hydraulic analyses or Monte Carlo simulations when the system has a small failure probability. Accordingly, the advantages and constraints of applying the Chernoff bound for passive system reliability evaluation are discussed in this paper.

• Smart Structures and Systems
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• v.30 no.3
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• pp.245-253
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• 2022

A two-layer beam consisting of an elastoplastic layer and a functional layer made of shape memory alloy (SMA) TiNi is considered. Constitutive relations for SMA are set by a microstructural model capable to calculate strain increment produced by arbitrary increments of stress and temperature. This model exploits the approximation of small strains. The equations to calculate the variations of the strain and the internal variables are based on the experimentally registered temperature kinetics of the martensitic transformations with an account of the crystallographic features of the transformation and the laws of equilibrium thermodynamics. Stress and phase distributions over the beam height are calculated by steps, by solving on each step the boundary-value problem for given increments of the bending moment (or curvature) and the tensile force (or relative elongation). Simplifying Bernoulli's hypotheses are applied. The temperature is considered homogeneous. The first stage of the numerical experiment is modeling of preliminary deformation of the beam by bending or stretching at a temperature corresponding to the martensitic state of the SMA layer. The second stage simulates heating and subsequent cooling across the temperature interval of the martensitic transformation. The curvature variation depends both on the total thickness of the beam and on the ratio of the layer's thicknesses.

• Journal of the Korean Burn Society
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• v.24 no.2
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• pp.74-76
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• 2021

Postburn scar contracture of sole can cause musculoskeletal deformity, restricted range of motion, and decreased quality of life. It is very important to exhibit similar characteristics of the sole when reconstructing the sole because it has to resist shearing force and weight bearing. In this case, we performed medialis pedis free flap for the postburn scar contracture of the sole and the flap survived without complication. The patient satisfied with functional and aesthetic outcomes. Medialis pedis free flap, which is harvested adjacent to the sole, can show similar characteristic of the sole and maintain adequate contour. Moreover, this flap can be harvested without sacrifice of major vessel or nerve. Due to these advantages, medialis pedis free flap can be an ideal option for the reconstruction of the sole.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.214-217
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• 2022

The effect of inductively coupled plasma (ICP) treatment with O₂ gas on the surface properties of poly(ether sulfone) (PES) was investigated. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical characteristics of the O₂ plasma-treated PES films. The surface roughness of the pristine and O₂ plasma-treated PES films for different RF powers of the ICP was determined using an atomic force microscope (AFM). The contact angles of the PES films were also measured, using which the surface free energies were calculated. The O1s XPS spectra of the PES films revealed that the number of polar functional groups increased following the O₂ plasma treatment. The AFM analysis showed the average surface roughness increased from 1.01 to 4.48 nm as the RF power of the ICP was increased. The contact angle measurements revealed that the PES films became more hydrophilic as the RF power of the ICP was increased. The total surface energy increased with the RF power of the ICP, resulting from the increased polar energy component.

• Elastomers and Composites
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• v.57 no.4
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• pp.197-204
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• 2022

Recently, the demand has increased for protective clothing materials capable of shielding the wearer from bullets, fragment bullets, knives, and swords. It is therefore necessary to develop light and soft protective clothing materials with excellent wearability and mobility. To this end, research is being conducted on hybrid design methods for various highly functional materials, such as carbon nanotube (CNT) sheets, which are well known for their low weight and excellent strength. In this study, a hybrid protective material using CNT sheets was developed and its performance was evaluated. The material design incorporated a bonding method that used a binder for interlayer combination between the CNT sheets. Four types of binders were selected according to their characteristics and impregnated within CNT sheets, followed by further combination with aramid fabric to produce the hybrid protective material. After applying the binder, the tensile strength increased significantly, especially with the phenoxy binder, which has rigid characteristics. However, as the molecular weight of the phenoxy binder increased, the adhesive force and strength decreased. On the other hand, when a 25% lightweight-design and high-molecular-weight phenoxy binder were applied, the backface signature (BFS) decreased by 6.2 mm. When the CNT sheet was placed in the middle of the aramid fabric, the BFS was the lowest. In a stab resistance test, the penetration depth was the largest when the CNT sheet was in the middle layer. As the binder was applied, the stab resistance improvement against the P1 blade was most effective.