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Motility enhancement of bacteria actuated microstructures using selective bacteria adhesion
Park, Sung Jun,Bae, Hyeoni,Kim, Joonhwuy,Lim, Byungjik,Park, Jongoh,Park, Sukho Royal Society of Chemistry 2010 Lab on a chip Vol.10 No.13
<P>Microrobots developed by the technological advances are useful for application in various fields. Nevertheless, they have limitations with respect to their actuator and motility. Our experiments aim to determine whether a bioactuator using the flagellated bacteria <I>Serratia marcescens</I> would enhance the motility of microrobots. In this study, we investigate that the flagellated bacteria <I>Serratia marcescens</I> could be utilized as actuators for SU-8 microstructures by bovine serum albumin-selective patterning. Firstly, we analyze the adherence of the bacteria to the SU-8 micro cube by selective patterning using 5% BSA. The results show that number of attached-bacteria in the uncoated side of the selectively- coated micro cube with BSA increased by 200% compared with that in all sides of the non treated micro cube. Secondly, the selectively BSA coated micro cube had 210% higher motility than the uncoated micro cube. The results revealed that the bacteria patterned to a specific site using 5% BSA significantly increase the motility of the bacteria actuated microstructure.</P> <P>Graphic Abstract</P><P>The bacteria patterned to a specific site using 5% BSA significantly increase the motility of the bacteria actuated microstructure. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c000463d'> </P>
박종오(Jongoh Park),이달희(Dal-Heui Lee),우익(Ik Woo) 한국암반공학회 2017 터널과지하공간 Vol.27 No.5
수압암반절개기술은 천공된 시추공에 설치된 이중패커의 인터벌에 암반의 인장응력 이상의 수압을 가하여 균열을 발생시킴으로써 암반을 절개시키는 방법이다. 본 연구에서는 흑운모화강암 사면에 대하여 다양한 배열설계 및 주입설계에 따라 수압암반절개기술을 현장에 적용하였다. 실험 결과, 주입에 따라 새로운 균열이 발생되어 주변 공과 연결되거나 기존 균열이 연장되어 암반이 파괴되었다. 특히, 본 실험에서는 유도 슬롯과 평행한 방향을 지닌 균열이 발생되어 균열 생성방향을 제어할 수 있는 가능성을 제시하였다. 균열생성에 대한 제어 기술을 발전시키기 위해선, 균열생성에 영향을 미치는 여러 요소를 고려한 다양한 배열설계 및 주입설계를 암반 현장에 적용하여야 할 것이다. Hydraulic rock splitting is a technique which leads to failure of rockmass by means of water injection with a pressure higher than the tensile strength of rockmass, using straddle packer installed in boreholes drilled from free surface. Field tests were conducted in this study for several slopes of biotite granite according to various designs for borehole layout and water injection. Test results showed that new cracks were generated to connect to adjacent holes or that pre-existed cracks were propagated by injection, finally leading to failure. In particular, this study suggests the possibility of controlling the direction of generated cracks with guide slot, since new cracks were generated parallel to the guide slots carved on a borehole wall before injection. Various types of borehole layout and injection methods should be further developed for the practical uses, considering the factors influencing on crack generation.
Investigation of Generative Contactile Force of Frog Muscle under Electrical Stimulation
Sukho Park,Changyeol Jee,Jiwoon Kwon,Sungjin Park,Byungkyu Kim,Jongoh Park 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.11
Recently, the microrobots powered by biological muscle actuators were proposed. Among the biological muscle actuators, frog muscle is well known as a good muscle actuator and has a large displacement, actuation forces and piezoelectric properties. Therefore, for the application of the biomimetic microrobot, this paper reports the electromechanical properties of frog muscle. First of all, the experimental setup has been established for measuring generative force of the frog muscle. Through the various electrical stimulating inputs to the frog muscle, we measured the contractile force of the frog muscle. From the measuring results, we found that the actuating contractile force responses of the frog muscle are determined by the amplitude, frequency, duty ratio, and wave form of the stimulation signal. This study will be beneficial for the development of the microrobot actuated by frog muscle.
박종오 ( Jongoh Park ),이달희 ( Dal-heui Lee ) 대한지질공학회 2016 지질공학 Vol.26 No.3
석회암 광산과 화강섬록암 석산에서의 수압암반절개 시험은 1과 2 자유면에서 3개와 1개의 이중패커를 이용하여 인터벌 내에 수압을 가하는 방식으로 적용하였다. 시험 결과는 약 6.5MPa과 13.0 MPa에서 2 자유면과 평행한 방향으로 균열이 발생하였으며, 1 자유면에서 14.0 MPa의 수압에 의해 상부 천공부에 있는 1개의 이중패커가 파손되었지만 암반 균열이 발생되지 않는 결과를 도출하였다. 인터벌의 수압은 기존 균열 및 신규 균열을 통해 많은 물이 분출되면서 지속적으로 수압이 걸리는 것을 확인하였다. Tests of hydraulic rock splitting were conducted using double packer at the 1, 2 free surface in the limestone mining and gra-nodiorite Suksan area, respectively. The method of hydraulic rock splitting was applying hydraulic power in the interval layer using double packer. As a result of tests, a crack occurred. At about 6.5 MPa and 13 MPa, a crack occurred in 2 free surface. Any crack did not occur in the 1 free surface. Rather, used 1 double packer was broken in the 1 free surface. Also, it was confirmed that the water pressure of the interval increased through the existing crack and the new crack in the test areas.
An Ergonomic Evaluation of an One–Touch System for Shoe Lacing
Kwangae Park,Jangwoon Park,Younggeun Choi,Hyewon Lee,Jongoh Hwang,Heecheon You 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.11
Background: Ordinary shoes have an inconvenience that the laces should be retied when they are untied, otherwise the wearer could fall down or have a safety accident. Tying shoe laces is especially uncomfortable for seniors and disabled people with difficulty using hands. Objective: Present study validates the ergonomic effects of the one-touch system developed for refining the inconvenience of tying laces and improving prevention of being untied of laces. Method: Validation of the one-touch system has been conducted with eleven seniors, ten disabled people, and ten ordinary adults. They evaluated the one-touch system and the ordinary shoe laces in terms of subjective criteria (overall satisfaction, convenience of use, wearing comfort, securing stability, and motion efficiency) and objective criteria (tying time). Results: The level of overall satisfaction of the one-touch system was 1.6 times higher than ordinary lace shoes where the one-touch system got 6.3 points each from seniors and disabled people, and 5.1 points from ordinary adults while ordinary lace shoes got 3.9 points from seniors, 3.7 points from disabled people, and 3.2 points from ordinary adults. Especially in the group of disabled people and seniors with difficulty using hands, the result of the one-touch system was 1.5 to 4.6 times higher than those of the ordinary lace shoes in terms of convenience of use, securing stability, and motion efficiency. In terms of tying time, buckling the one-touch system shoes took 2.3 to 3.8 times quicker than tying ordinary shoe laces where it took 8.6 seconds for seniors, 11.8 seconds for disabled people, and 6.9 seconds for ordinary adults to tie ordinary shoe laces, while it took 3.2 seconds for seniors, 5.2 seconds for disabled people, 1.8 seconds for ordinary adults to buckle the one-touch system shoes. Conclusion: It was validated that the way of buckling the one-touch system shoes is more satisfactory and efficient than the way of tying the ordinary shoe laces. Application: The one-touch system is highly expected to be applicable to shoes with laces. Moreover, it could be used in product design for seniors and disabled people with difficulty using hands, and children group.