• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.97-110
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• 1999

The new stick make-up product was studied by using a gel, which is a viscous complex formed with clay minerals, vitamins A and E and fluorinated liquid polymer with a 1500 molecular weight. The gel cannot be obtained with any random combination of clay minerals and the ingredients described above. It takes the sequential manufacturing method as follows to get this kind of gel. Firstly, clay minerals and liquid polymers have to be pre-mixed in order to saturate the liquid polymers with the clay minerals. Then the on-processed gel has to be finely crystallized. The clay minerals, which are the core elements for this gel, were used as a function of Binder & Buffer and liquid polymer was mixed together for the deterioration of the surface tension of each component and to form a functional film in the gel. This liquid polymer was combined with clay minerals because it is not miscible with most oils and solvents. Waxes have a function of keeping a solid status in the stick. We reduced the usage of waxes by putting clay minerals as buffer in the proportion of 0.5:1 with oil phase. Ceramide takes care of the skin when used regularly and maintains the skin's moisture. Vitamins A and E contribute to preventing skin aging by the activation of skin cells. We could get the stable viscous gel, which has about 80% oil phase using clay minerals and liquid polymer. The crystalline structures of gel were surface-chemically-analyzed using SEM and Image Analyzer and were thermodynamically analyzed using DSC. Surface tension test and softness were done by Rheometer. In the end, these characteristics were verified by consumer panel tests in Seoul, Daegeon and Pusan in Korea and Hokkaido, Osaka and Miyazaki in Japan with correlation to the climate.

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.97-110
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• 1999

The new stick make-up product was studied by using a gel, which is a viscous complex formed with clay minerals, vitamins A and I and fluorinated liquid polymer with a 1500 molecular weight. The gel cannot be obtained with any random combination of clay minerals and the ingredients described above. It takes the sequential manufacturing method as follows to get this kind of gel. Firstly, clay minerals and liquid polymers have ·to be pre-mixed in order to saturate the liquid polymers with the clay minerals. Then tile on-processed gel has to be finely crystallized. The clay minerals, which are the core elements for this gel, were used as a function of Binder & Buffer and liquid polymer was mixed together for the deterioration of the surface tension of each component and to from a functional film in the gel. This liquid polymer was combined with clay minerals because it is not miscible with most oils and solvents. Waxes have a function of keeping a solid status in the stick. We reduced the usage of waxes by putting clay minerals as buffer in the proportion of 0.5 : 1 with oil phase. Ceramide takes care of the skin when used regularly and maintains the skin’s moisture. Vitamins A and I contribute to preventing skin’aging by the activation of skin cells. We could get the stable viscous gel, which has about 80% oil phase using clay minerals and liquid polymer, The crystal 1 me structures of gel were surface-chemical1y-analyzed using SEM and Image Analyzer and were thermodynamically analyzed using DSC, Surface tension test and softness were done by Rheometer. In the end, these characteristics were verified by consumer panel tests in Seoul, Baegeon and Pusan in Korea and Hokkaido, Oska and Miyazaki in Japan with correlation to the climate.

• Elastomers and Composites
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• v.39 no.3
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• pp.193-208
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• 2004

Morphology of injection molded polymer blend was investigated by experimental and theoretical approach. In experiments, the effects of injection speed and injection temperature on the morphology of injection molded MPPO/Nylon 6 blend were investigated. The morphology distribution across the part thickness was clearly observed in injection molded blend. We could observe several distinct regions across the thickness of molded part: skin layer, subskin layer and core region. The skin layer where the dispersed phase is fine and highly deformed to the flow direction is observed to be located near the part surface. The subskin layer located at inner region of the skin layer also observed. In the subskin layer, the dispersed phase is coarser than that of skin layer and deforms to the flow direction. Based on the experimental results, the calculation scheme to predict the morphology of injection molded polymer blend was suggested. The morphology of injection molded polymer blend could be predicted in corporation with the result of flow analysis obtained from commercial software for injection molding process and the theory of drop behavior under the flow. The suggested calculation scheme could predict the effect of injection conditions on the morphology of injection molded parts.

• Steel and Composite Structures
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• v.36 no.2
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• pp.187-196
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• 2020

Double skin composite wall system owns several structural merits in terms of high load-carrying capacity, large axial stiffness, and favorable ductility. A recently proposed form of truss connector was used to bond the steel plates to the concrete core to achieve good composite action. The structural behavior of rectangular high walls under compression and T-shaped high walls under eccentric compression has been investigated by the authors. Furthermore, the influences of the truss spacings, the wall width, and the faceplate thickness have been previously studied by the authors on short walls under uniform compression. This paper experimentally investigated the effect of width-to-thickness ratio on the compressive behavior of short walls. Compressive tests were conducted on three short specimens with different width-to-thickness ratios. Based on the test results, it is found that the composite wall shows high compressive resistance and good ductility. The walls fail by local buckling of steel plates and crushing of concrete core. It is also observed that width-to-thickness ratio has great influence on the compressive resistance, initial stiffness, and strain distribution across the section. Finally, the test results are compared with the predictions by modern codes.

• Journal of the Korean Wood Science and Technology
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• v.28 no.1
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• pp.18-27
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• 2000

Even the same materials are assembled in flush door skin panel, warping is not simply prevented under the changes of environmental conditions since wood and wood-based material have large variations in their physical and mechanical properties. The parameters such as linear movement coefficient(LMC), modulus of elasticity (MOE), required to predict warping could be estimated by oven drying method and dynamic method instead of American Society for Testing Materials(ASTM) procedure. The relationship between warping and LMC was curvilinear, while it between warping and MOE was linear. LMC had a larger effect on warping than MOE. Material propensity of skin panel such as hardboard and plywood showed normal distributions. The variation of material properties, however, was much larger in plywood than in hardboard. Monte Carlo simulation also indicated that rejection ratio of flush door due to the occurrence of warping could be predicted with consideration of the relationship of warping and parameters of probability distribution of MOE, LMC, and moisture content.

• The Korean Journal of Physiology
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• v.10 no.1
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• pp.61-66
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• 1976

Rectal temperature, skin temperature and oxygen consumption were measured in five women divers during diving under two conditions a) wearing a cotton bathing suit and b) wearing a diving suit and the following results were obtained. 1. The duration of the diving period was 30 min with the cotton bathing suit whereas it was above 120 min with the diving suit. 2. The average rectal temperature fell to $34.5^{\circ}C$ after 30 min of diving with the cotton bathing suit. On the other hand, with the diving suit, immediately after submersion, the rectal temperature rose about $3^{\circ}C$ and remained at about $39^{\circ}C$ throughout the diving period of 120 min. 3. Average mean skin temperature during diving was $11^{\circ}C$ and $21^{\circ}C$ with cotton bathing suit and with the diving suit, respectively. The mean body temperature fell to $25^{\circ}C$ with the cotton bathing suit while it reached $32^{\circ}C$ with the diving suit at the end of each diving period. 4. Oxygen consumption during diving was three fold of the pre-dive level with the cotton bathing suit but it was two fold with the diving suit. 5. Total extra heat loss was 323 kcal during 120 min of diving with the diving suit. On the contrary, with the cotton bathing suit, it was 528 kcal for 30 min, These results may suggest that the prolongation of the diving period with the diving suit is primarily due to maintenance of core temperature at more or less physiological level as a result of reduction in conductive heat loss from the body surface to the water and the Preferential distribution of blood in the core area.

• Geomechanics and Engineering
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• v.31 no.1
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• pp.99-112
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• 2022

The present study examines the natural frequencies (NFs) of perfect/imperfect functionally graded sandwich beams (P/IP-FGSBs), which are composed of a porous core constructed of functionally graded materials (FGMs) and a homogenous isotropic metal and ceramic face sheets resting on elastic foundations. To accomplish this, the material properties of the FGSBs are assumed to vary continuously along the thickness direction as a function of the volume fraction of constituents expressed by the modified rule of the mixture, which includes porosity volume fraction represented using four distinct types of porosity distribution models. Additionally, to characterize the reaction of the two-parameter elastic foundation to the Perfect/Imperfect (P/IP) FGSBs, the medium is assumed to be linear, homogeneous, and isotropic, and it is described using the Winkler-Pasternak model. Furthermore, the kinematic relationship of the P/IP-FGSBs resting on the Winkler-Pasternak elastic foundations (WPEFs) is described using trigonometric shear deformation theory (TrSDT), and the equations of motion are constructed using Hamilton's principle. A closed-form solution is developed for the free vibration analysis of P/IP-FGSBs resting on the WPEFs under four distinct boundary conditions (BCs). To validate the new formulation, extensive comparisons with existing data are made. A detailed investigation is carried out for the effects of the foundation coefficients, mode numbers (MNs), porosity volume fraction, power-law index, span to depth ratio, porosity distribution patterns (PDPs), skin core skin thickness ratios (SCSTR), and BCs on the values of the NFs of the P/IP-FGSBs.

• Computers and Concrete
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• v.33 no.1
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• pp.27-39
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• 2024

In this study, the authors investigate the free vibration behavior of three-phases functionally graded sandwich plates using a novel nth-order shear deformation theory. These plates are composed of a homogeneous core and two face-sheet layers made of different functionally graded materials. This is the novel type of the sandwich structures that can be applied in many fields of mechanical engineering and industrial. The proposed theory only requires four unknown displacement functions, and the transverse displacement does not need to be separated into bending and shear parts, simplifying the theory. One noteworthy feature of the proposed theory is its ability to capture the parabolic distribution of transverse shear strains and stresses throughout the plate's thickness while ensuring zero values on the two free surfaces. By eliminating the need for shear correction factors, the theory further enhances computational efficiency. Equations of motion are established using Hamilton's principle and solved via Navier's solution. The accuracy and efficiency of the proposed theory are verified by comparing results with available solutions. The authors then use the proposed theory to investigate the free vibration characteristics of three-phases functionally graded sandwich plates, considering the effects of parameters such as aspect ratio, side-to-thickness ratio, skin-core-skin thicknesses, and power-law indexes. Through careful analysis of the free vibration behavior of three-phases functionally graded sandwich plates, the work highlighted the significant roles played by individual material ingredients in influencing their frequencies.

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.174-178
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• 2009

Purpose: We introduce arthroscopic assisted core decompression for humeral head osteonecrosis. Operative technique: After diagnostic shoulder arthroscopy is performed using posterior and anterior portal, we make a 2 cm lateral skin incision approximately 3 cm distal to 1/3 of lateral margin of the acromion and place short gray cannula to prevent adjacent soft tissue injury when insert guide pin. Under C-arm fluoroscopic and arthroscopic guidance, 3 to 4 guide pins are inserted toward the necrotic area. Then we perform drilling using 7.0 mm reamer. Conclusion: We believe this technique is a less invasive approach and avoids the complications comparing to deltopectoral approach. Arthroscopic assisted core decompression is an effective procedure in management of early stage of the humeral head osteonecoris.