• Title/Summary/Keyword: skin and structure

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Evaluation of the effect of smart façade systems in reducing dynamic response of structures subjected to seismic loads

  • Samali, Bijan;Abtahi, Pouya
    • Earthquakes and Structures
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    • v.11 no.6
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    • pp.983-1000
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    • 2016
  • To date the engineering community has seen facade systems as non-structural elements with high aesthetic value and a barrier between the outdoor and indoor environments. The role of facades in energy use in a building has also been recognized and the industry is also witnessing the emergence of many energy efficient facade systems. This paper will focus on using exterior skin of the double skin facade system as a dissipative movable element during earthquake excitation. The main aim of this study is to investigate the potential of the facade system to act as a damper system to reduce earthquake-induced vibration of the primary structure. Unlike traditional mass dampers, which are usually placed at the top level of structures, the movable/smart double skin facade systems are distributed throughout the entire height of building structures. The outer skin is moveable and can act as a multi tuned mass dampers (MTMDs) that move and dissipate energy during strong earthquake motions. In this paper, using a three dimensional 10-storey building structure as the example, it is shown that with optimal choice of materials for stiffness and damping of brackets connecting the two skins, a substantial portion of earthquake induced vibration energy can be dissipated which leads to avoiding expensive ductile seismic designs. It is shown that the engineering demand parameters (EDPs) for a low-rise building structures subjected to moderate to severe earthquakes can be substantially reduced by introduction of a smart designed double skin system.

Enhancement of Transdermal Drug Delivery Using Ultrasound (초음파를 이용한 경피약물수송의 촉진)

  • Park, Seung-Kyu;Kim, Tae-Youl
    • The Journal of Korean Physical Therapy
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    • v.13 no.3
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    • pp.719-726
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    • 2001
  • Transdermal drug delivery offers various advantages over conventional drug delivery systems, such as avoidance gastrointestinal degradation and hepatic first-pass effect. encourages patient compliance. and possible sustained release of drugs. However, transdermal transport of drugs is low permeability of the stratum corneum, the superficial layer of the skin. Many physicochemical and biological factors influencing transdermal transport is described together with the corresponding experimental and clinical results. Phonophoresis is medical treatment with drugs introduced into the skin by ultrasound energy. Enhanced drug penetration is through to result from the biophysical alterations of skin structure by ultrasound waves. The frequency used for phonophoresis is usually from 20 kHz to 15MHz. Phonophoresis can be categorized in to three ranges: low-frequency range(below 1 MHz). therapeutic frequency range(1 to 3MHz), and high-frequency range(above 3 MHz). The depth of penetration of ultrasound into skin is inversely proportional to the frequency. Cavitation may cause mechanical stress. temperature elevation, or enhanced chemical reactivity causing drug transport. One theory is that ultrasound affects the permeation of the stratum corneum lipid structure as the limiting step in permeating through the skin. The range of indications for phonophoresis is wide. Aspecific classification of the range of indications is obtained by classification of pathological conditions. The continuous research is needed for many interesting issucs of phonophoretic transdermal delivory in new future.

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Hydrolysis , Skin Permeation and In Vivo Whitening Effect of Kojic Acid Monostearate as an Antimelanogenic Agent (멜라닌생성억제제인 코직산 모노스테아레이트의 가수분해와 피부투과성 및 in vivo 미백효과)

  • Ha, Yong-Ho;Yu, Sung-Un;Kim, Dong-Sup;Lim, Se-Jin;Choi, Young-Wook
    • YAKHAK HOEJI
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    • v.42 no.1
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    • pp.39-45
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    • 1998
  • Kojic acid, antimelanogenic agent, has been widely used in cosmetics to lighten the skin color. However, it has skin irritancy and instability against pH, temperature and light. To overcome these problems and optimize the molecular structure of kojic acid (KA), a prodrug, kojic acid monostearate(KMS), has been synthesized to modify the topical drug delivery in the point of sustained release of the parent drug via enzymatic hydrolysis during skin absorption. The prodrug was tested for enzymatic hydrolysis with cytosolic fraction of hairless mouse, skin. From the in vitro skin permeation study through hairless mouse skin, we found that KMS was retained in the skin and generated KA continuously by the skin esterase cleavage. In addition, topical formulations of o/w type creams and polyolprepolymer-containing cream were further tested for whitening effects using in vivo yellow skin guinea pig model.

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Flexural performance of double skin composite beams at the Arctic low temperature

  • Yan, Jia-Bao;Dong, Xin;Wang, Tao
    • Steel and Composite Structures
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    • v.37 no.4
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    • pp.431-446
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    • 2020
  • This paper presents the flexural performance of double skin composite beams (DSCBs) at different Arctic low temperatures. 12 DSCBs were prepared and tested under two-point loading at different Arctic low temperatures of 20, -30, -50, and -70℃. The studied parameters include low-temperature level (T), steel-faceplate thickness (t), shear span ratio (λ), and spacing of headed studs (S). The experimental investigations under two-point loading tests showed that flexural failure occurred to all DSCBs, even including the specimen designed with the small λ ratio of 2.9. The ultimate strength behaviours of DSCBs were improved due to the improved mechanical properties of constructional materials and the confinement on shear connectors. The DSCB subjected to two-point loading and low temperatures exhibits a five-stage working mechanism. The stiffness and strength indexes of DSCBs increase linearly with temperature and t value increasing, while decreasing as shear span ratio boosts. In the contrast, the change of S value from 150 to 200 mm has little effect on the ultimate strength behavior of DSCB.

A Study on Image Construction of Skin based on Expandable Patternization Process (확장적 패턴화 과정을 바탕으로 한 스킨 이미지 구축에 관한 연구)

  • Choi, Yun-Mi;Kim, Jong-Jin
    • Korean Institute of Interior Design Journal
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    • v.17 no.2
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    • pp.30-38
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    • 2008
  • It has been stated that the outer skin of an architecture should be related to and express the interior programs. It was rather moral issue than practicality. In contemporary urban cities, this nicely-linked relationship between exterior and interior has become much more complex and, in many cases, is no more valid. It tends that contemporary architectural skin is somehow separately developed and has its own logic to be independent from what is inside. This research focuses on these sort of logical design process to make unique image of skin in which conceptual thinking, spatialization and materialization are mixed together. More specifically this study articulates' expandable patternization process' based on the notion that it has a crucial role to systematically construct an image of skin. Expandable patternization has a couple of stages to complete an architectural skin. The first element is a single unit and the second is organization or arrangement of units based on a logical process. Lastly, the third is spatialization after relating the skin to the interior programs as well as environmental surroundings. It is found that, although, in most related projects, the architect or designer has followed his or her own preference or design tendencies, many skin projects has based the given unique characteristics from the beginning. This study concludes that skin design is not just an image making, but has an important role to amalgamate various aspects of an architectural projects: programs, concept of architect, environment, structure as well as image.

Improving the Skin Penetration of Cosmetics Containing Omega 3 Fatty Acids

  • KIM, Han-Sook;HAN, Sien-Ho
    • Journal of Wellbeing Management and Applied Psychology
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    • v.4 no.4
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    • pp.15-25
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    • 2021
  • Purpose: The purpose of this study is to form a new cosmetic market through the development of a composition with high skin permeability after adding omega 3 to Aloe Vera soothing gel products. Research design, data and methodology: In this study, omega-3 fatty acids were added to cosmetic products in the form of soothing gels. By applying nanoparticle technology to rapidly increase the penetration of raw materials into the skin, characteristics related to skin moisture and regeneration were determined. Omega-3 was used as a raw cosmetic material. Then 5% and 15% nanoparticle aqueous products containing omega-3 were prepared. The developed water hydrate was subjected to skin permeability test using artificial skin. Results: 53 hours of artificial transdermal penetration of the developed composition, the ethanol-based omega-3 containing nanoparticle solubilized raw material was about three times higher penetration than the ethanol-based omega-3 containing nanoparticle solubilized raw material. Conclusions: The raw material product (SR-1901) containing 5% of omega-3 nanoparticle water hydrate has skin regeneration ability and pain reduction effect. It can be expected that the skin cosmetics market will be reorganized into a new distribution structure and opportunity through omega-3 supplemented soothing gel cosmetics with improved efficacy than existing cosmetics.

Morphology and Histochemistry of the Skin of the Mud Loach, Misgurnus mizolepis, in Relation to Cutaeneous Respiration

  • Park, Jong-Young;Kim, Ik-Soo;Kim, So-Young
    • Animal cells and systems
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    • v.5 no.4
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    • pp.303-308
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    • 2001
  • The skin structure of Misgurnus mizolepis was studied based on the microanatomical investigation of skin fragments taken from four regions. The epidermis was distinguished by two types of skin glands, a small mucous cell and a large club cell. The mucous cell was acid sulfomucins (some sialomucins) but the club cell did not give any histochemical tests for mucosubstances. The presence of a well defined lymphatic system with small lymphocytes was established in the stratum germinativum layer of the epidermis. A large number of blood capillaries run very close to each other just below the basement membrane, and a definite area giving AB and PAS positive was present between the basement membrane and scale. These structural features of skin in M. mizolepis seem to be closely related with cutaneous respiration.

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Effect of Heating on Polymerization of Pig Skin Collagen Using Microbial Transglutaminase

  • Erwanto, Yuny;Muguruma, Michio;Kawahara, Satoshi;Tsutsumi, Takahiko;Katayama, Kazunori;Yamauchi, Kiyoshi;Morishita, Toshiro;Morishita, Toshiro;Watanabe, Shohei
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.8
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    • pp.1204-1209
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    • 2002
  • Polymerization of heated or unheated pig skin collagen using microbial transglutaminase (MTGase) was investigated. Pig skin collagen samples were heated or left unheated, then enzymatically polymerized with MTGase. SDS-PAGE was conducted to confirm the intermolecular polymer and the results showed similar bands between samples without MTGase and unheated samples with MTGase. The polymerized product of pig skin collagen was not formed in unheated samples, even when MTGase was added during incubation. Different results were obtained from samples heated at $80^{\circ}C$ and $100^{\circ}C$ for 2 min, whereas the SDS-PAGE pattern indicated that a polymer band was generated in both cases. The heat treatment successfully modified the native structure of collagen and also made collagen more reactable in the MTGase polymerization system. Scanning Electron Microscope (SEM) investigation of pig skin collagen showed a biopolymer structure through intermolecular collagen crosslinking, while there were no intermolecular crosslinks in samples not treated with MTGase. There were no significant differences in fibril diameter between treated samples and controls. These results suggest that heat treatment of native pig skin collagen enhanced the polymerization capability of MTGase.

A Portable Skin Elasticity Measuring Device Based on Indentation Method Using Piezoelectric Effect (압전효과를 이용한 압인방식의 휴대용 피부탄력 측정장치)

  • Park, Jun-Young;Kim, Myoung Nam
    • Journal of Korea Multimedia Society
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    • v.25 no.9
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    • pp.1307-1315
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    • 2022
  • In this paper, we proposed and developed a new portable skin elasticity measuring device based on the indentation method using piezoelectric effect. The proposed device is designed to minimize the uncertainty caused by the layer structure of the skin when measuring the elasticity of the skin. And, we developed a piezoelectric-based thin-film pressure sensor that can measure quantitatively and quickly during repeated measurement as a device sensor. To confirm the effectiveness of the proposed measuring device, it was compared with the experimental results of the conventional measuring devices under the same experimental conditions, and statistical correlation analysis was performed between the experimental data of the proposed measuring device and the experimental data of the conventional measuring devices. As a result of the correlation analysis, it was confirmed that the proposed measuring device had a high correlation with the conventional measuring devices. Therefore, it was confirmed that the proposed skin elasticity measuring device was effective.

Variation of Supersonic Aircraft Skin Temperature under Different Mach number and Structure (비행마하수와 형상에 따른 초음속 항공기 표면온도 변화)

  • Cha, Jong Hyun;Kim, Taehwan;Bae, Ji-Yeul;Kim, Taeil;Jung, Daeyoon;Cho, Hyung Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.4
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    • pp.463-470
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    • 2014
  • Stealth technology of combat aircraft is most significant capability in recent air battlefield. As the detector of IR missiles is being developed, IR stealth capability which is evaluated by IR signature level become more important than it was in previous generation. Among IR signature of aircraft from various sources, aerodynamic heating dominates in long-wavelength IR spectrum of $8{\sim}12{\mu}m$. Skin temperature change by aerodynamic heating which is derived by effects of Mach number and structure. The 4th and 5th generation aircraft are selected for calculation of the skin temperature, and its height and velocity in numerical conditions are 10,000 m and Ma 0.9~1.9 respectively. Aircraft skin temperature is calculated by computing convection of fluid and conduction, convection and radiation of surface. As the aircraft accelerates to higher Mach number, maximum skin temperature increases more rapidly than average temperature and temperature distribution changes in more sharp, interactive ways. The 4th generation aircraft whose shape is more complex than that of the 5th generation aircraft have complicated temperature distribution. On the other hand, the 5th generation aircraft whose shape is relatively simple shows plain temperature distribution and lower skin temperature in terms of both average and maximum value.