• Title/Summary/Keyword: Engineering, and physical parameters

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Development of Customizable Fluorescence Detection System using 3D Printer (3D 프린터를 활용한 맞춤형 휴대용 형광측정 장치 개발)

  • Cho, Kyoung-rae;Seo, Jeong-hyeok;Choe, Se-woon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2019.05a
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    • pp.278-280
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    • 2019
  • Flow cytometer is one of the instrument that can measure various optical properties of a single cell or microparticle. These parameters including size, granularity, and fluorescence intensity are determined by the physical and optical interaction of the cells with excitation light source. However, users have some difficulties such as high cost, size of instrument, and limited fluorescence selectivity. In addition, abundant data is also unintentionally acquired even though user wants to have a single optical parameter. For these reasons, the use of flow cytometer is more challenging for researchers to apply their study. Therefore, the proposed study aims to develop a low-cost portable fluorescence acquisition system using a commercially available light-emitting diode and photodiode. It is designed by a 3D printer, and fluorescence selectivities are increased by changing of the light source / optical filter / detection sensor. Various number sets of fluorescently labeled cells were measured, and its feasibility was evaluated through the proposed system. As a result, acquried fluorescence intensities were proportional to the concentration of the cells and showed high linearity.

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Study on Adsorption Equilibrium, Kinetic and Thermodynamic Parameters of Murexide by Activated Carbon (입상 활성탄에 의한 Murexide의 흡착 평형, 동력학 및 열역학 파라미터에 관한 연구)

  • Lee, Jong-Jib
    • Clean Technology
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    • v.25 no.1
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    • pp.56-62
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    • 2019
  • The equilibrium, kinetic and thermodynamic parameters of adsorption of murexide by granular activated carbon were investigated. The experiment was carried out by batch experiment with the variables of the amount of the adsorbent, the initial concentration of the dye, the contact time and the temperature. The isothermal adsorption equilibrium was best applied to the Freundlich equation in the range of 293 ~ 313 K. From the separation factor (${\beta}$) of Freundlich equation, it was found that adsorption of murexide by granular activated carbon could be the appropriate treatment method. The adsorption energy (E) obtained from the Dubinin- Radushkevich equation shows that the adsorption process is a physical adsorption process. From the kinetic analysis of the adsorption process, pseudo second order model is more consistent than pseudo first order model. It was found that the adsorption process proceeded to a spontaneous process and an endothermic process through Gibbs free energy change ($-0.1096{\sim}-10.5348kJ\;mol^{-1}$) and enthalpy change ($+151.29kJ\;mol^{-1}$). In addition, since the Gibbs free energy change decreased with increasing temperature, adsorption reaction of murexide by granular activated carbon increased spontaneously with increasing temperature. The entropy change ($147.62J\;mol^{-1}\;K^{-1}$) represented the increasing of randomness at the solid-solution interface during the adsorption reaction of murexide by activated carbon.

Application of Laser Surface Treatment Technique for Adhesive Bonding of Carbon Fiber Reinforced Composites (탄소복합재 접착공정을 위한 CFRP의 레이저 표면처리 기법의 적용)

  • Hwang, Mun-Young;Kang, Lae-Hyong;Huh, Mongyoung
    • Composites Research
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    • v.33 no.6
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    • pp.371-376
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    • 2020
  • The adhesive strength can be improved through surface treatment. The most common method is to improve physical bonding by varying the surface conditions. This study presents the effect of laser surface treatment on the adhesive strength of CFRP. The surface roughness was patterned using a 1064 nm laser. The effects of the number of laser shots and the direction and length of the pattern on the adhesion of the CFRP/CFRP single joint were investigated through tensile tests. Tests according to ASTM D5868 were performed, and the bonding mechanism was determined by analyzing the damaged surface after a fracture. The optimized number of the laser shots and the optimized depth of the roughness should be required to increase the bonding strength on the CFRP surface. When considering the shear stress in the tensile direction, the roughness pattern in the direction of 45° that increases the length of the fracture path in the adhesive layer resulted in an increase of the adhesive strength. The surface treatment of the bonding surface using a laser is a suitable method to acquire a mechanical bonding mechanism and improve the bonding strength of the CFRP bonding joint. The study on the optimized laser process parameters is required for utilizing the benefits of laser surface processing.

The Effect of Direct Functional Magnetic Stimulation of the Lesion on Functional Motor Recovery in Spinal Cord Injured Rat (척수손상 흰 쥐의 운동기능 회복에 미치는 손상부위 직접자극을 통한 기능적 자기자극치료 효과)

  • Cho, Yun-Woo;Kim, Su-Jeong;Park, Hea-Woon;Seo, Jeong-Min;Hwang, Se-Jin;Jang, Sung-Ho;Lee, Dong-Gyu;Ahn, Sang-Ho
    • The Journal of Korean Physical Therapy
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    • v.23 no.1
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    • pp.53-58
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    • 2011
  • Purpose: The purpose of this study was to determine the effect of direct functional magnetic stimulation (FMS) of affected spinal cord on motor recovery following spinal cord injury in rats. Methods: After a contusion injury at the spinal level T9 using an NYU Impactor, functional magnetic stimulation was delivered by a magnetic stimulator through a round prototype coil (7 cm in diameter). Stimulation parameters were set as follows: repetition rate = 50 Hz (stimulus intensity 100% = 0.18 T), stimulation time = 20 min. Functional magnetic stimulation was administered twice a day, 5 days per week for 8 weeks starting 4 days after spinal cord injury. Functional magnetic stimulationwas delivered directly to the affected spinal cord. Outcomes of locomotor performance were assessed by the Basso Beattie Bresnahan (BBB) locomotor rating scale and by an inclined plane test weekly for 8 weeks. Results: In the BBB test, hindlimb motor function in the Functional magnetic stimulation group improved significantly more compared to the control group at 3, 4, 6, 7, and 8 weeks (p<0.05). In the inclined plane test, the angle of the plane in the functional magnetic stimulation group increased significantly more compared to the control group at 4, 5, 7, and 8 weeks (p<0.05). Conclusion: Our results demonstrate that direct Functional magnetic stimulation of the lesional site may have beneficial effects on motor improvement after spinal cord injury.

Optimum Abrasing Condition for Recycled Fine Aggregate Produced by Low Speed Wet Abraser Using Sulfur (황산수를 사용한 저속 습식 마쇄법에 의한 순환잔골재의 최적 마쇄조건)

  • Kim, Jin-Man;Kim, Ha-Seog;Park, Sun-Gyu;Kim, Bong-Ju;Kwak, Eun-Gu
    • Journal of the Korea Concrete Institute
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    • v.20 no.5
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    • pp.557-563
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    • 2008
  • Recently, the amount of disposed construction materials like demolished concrete is growing fast and the shortage of natural concrete aggregate is becoming serious. Therefore, recycling of aggregate extracted from the demolished concrete is getting important and use of the recycled aggregate for concrete has been seriously considered. However, the use of the recycled aggregate even for low performance concrete is very limited because recycled aggregate which contains large amount of old mortar has very low quality. Therefore, removing the paste sticked to the recycled aggregate is very important in the manufacturing of high quality recycled aggregate. We have studied a series of research according to complex crushing method, which is removed the ingredient of cement paste from recycled fine aggregate using both the low speed wet abrasion crusher as mechanical process and the acid treatment as chemical processes. This paper is to analyze the quality of the recycled fine aggregate produced by those complex method and investigate optimum manufacturing condition for recycled fine aggregate by the design of experiments. The experimental parameters considered are water ratio, coase aggregate ratio, and abrasion time. As a result, data concerning the properties of recycled sand were obtained. It was found that high quality recycled fine aggregate could be to obtain at the condition of the fifteen minute of abrasion-crusher time and the over 1.0 of recycled coarse aggregate ratio.

Computational study of orientation effects on thermal performance of natural convection cooled lightweight high performance hollow hybrid fin heat sinks (자연대류 냉각되는 경량고성능 할로우 하이브리드 휜 히트싱크의 열성능에 대한 방향 영향의 전산연구)

  • Effendi, Nico Setiawan;Kim, Kyoung-Joon
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.9
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    • pp.786-790
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    • 2016
  • This paper discusses numerically explored orientation effects on the thermal performance of hollow hybrid fin heat sinks (HHFHSs) under natural convection. A HHFHS consists of an array of hollow pin fins concatenated with plate fins and having perforations near the fin bases. Orientation effects on the footprint-based and mass-based thermal performance of the HHFHS were numerically studied for orientation angles ranging from $0^{\circ}$ to $180^{\circ}$. The performance of the HHFHS was compared with that of a pin fin heat sink (PFHS) having similar physical parameters. The results show that the thermal resistance of the HHFHS did not vary considerably from $0^{\circ}$ to $45^{\circ}$. The thermal resistance increased from $45^{\circ}$ to $90^{\circ}$, reached its maximum at $90^{\circ}$, and decreased consistently from $90^{\circ}$ to $180^{\circ}$. Dissimilar behaviors of the thermal resistance of the HHFHS vs. the PFHS resulted mainly from the effect of heat pumping induced by the internal flows of the hollow fins. Despite various orientations, the mass-based thermal resistance of the HHFHS was found to be nearly 30% smaller than that of the PFHS. This result shows the feasibility of the HHFHS for the lightweight thermal management of electronics under natural convection.

Development of a Dose Calibration Program for Various Dosimetry Protocols in High Energy Photon Beams (고 에너지 광자선의 표준측정법에 대한 선량 교정 프로그램 개발)

  • Shin Dong Oh;Park Sung Yong;Ji Young Hoon;Lee Chang Geon;Suh Tae Suk;Kwon Soo IL;Ahn Hee Kyung;Kang Jin Oh;Hong Seong Eon
    • Radiation Oncology Journal
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    • v.20 no.4
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    • pp.381-390
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    • 2002
  • Purpose : To develop a dose calibration program for the IAEA TRS-277 and AAPM TG-21, based on the air kerma calibration factor (or the cavity-gas calibration factor), as well as for the IAEA TRS-398 and the AAPM TG-51, based on the absorbed dose to water calibration factor, so as to avoid the unwanted error associated with these calculation procedures. Materials and Methods : Currently, the most widely used dosimetry Protocols of high energy photon beams are the air kerma calibration factor based on the IAEA TRS-277 and the AAPM TG-21. However, this has somewhat complex formalism and limitations for the improvement of the accuracy due to uncertainties of the physical quantities. Recently, the IAEA and the AAPM published the absorbed dose to water calibration factor based, on the IAEA TRS-398 and the AAPM TG-51. The formalism and physical parameters were strictly applied to these four dose calibration programs. The tables and graphs of physical data and the information for ion chambers were numericalized for their incorporation into a database. These programs were developed user to be friendly, with the Visual $C^{++}$ language for their ease of use in a Windows environment according to the recommendation of each protocols. Results : The dose calibration programs for the high energy photon beams, developed for the four protocols, allow the input of informations about a dosimetry system, the characteristics of the beam quality, the measurement conditions and dosimetry results, to enable the minimization of any inter-user variations and errors, during the calculation procedure. Also, it was possible to compare the absorbed dose to water data of the four different protocols at a single reference points. Conclusion : Since this program expressed information in numerical and data-based forms for the physical parameter tables, graphs and of the ion chambers, the error associated with the procedures and different user could be solved. It was possible to analyze and compare the major difference for each dosimetry protocol, since the program was designed to be user friendly and to accurately calculate the correction factors and absorbed dose. It is expected that accurate dose calculations in high energy photon beams can be made by the users for selecting and performing the appropriate dosimetry protocol.

Wearable antenna for Body area Network

  • Lim, Eng Gee;Wang, Zhao;Lee, Sanghyuk
    • Journal of Convergence Society for SMB
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    • v.3 no.2
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    • pp.27-32
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    • 2013
  • Wireless Body Area Networks (WBAN) have been made possible by the emergence of small and lightweight wireless systems such as Bluetooth, enabled devices and PDAs. Antennas are an essential part of any WBAN system and due to various technical requirements and physical constraints, careful consideration of their design and deployment is needed. This paper is proposing on the design of wearable antenna as parts of clothing to serve communications functions, such as tracking and navigation in health care applications. The substrates of the wearable antennas will be made from textile materials and since it is wearable, it should have a small size, be light weight, low maintenance, and unobtrusive. This proposed paper will also investigate the influence of different parameters for wearable antenna including types of textile/substrate to ensure that the antenna design satisfies WBAN requirements. The characteristics and behavior of the antenna need to adhere to specifications set by wireless standards and system technology requirements. This means that the transmitting and receiving frequency bands of the various units need to be chosen accordingly. Since there are restrictions on the level of power to which the human body can be exposed to, the antenna as well as other RF system components must be designed to meet these restrictions. Antenna gain, which directly affects power transmitted, is a critical parameter in ensuring power levels fall within the safety guidelines and so will be of primary importance in the design. The electromagnetic interaction between WBAN antennas and devices and the human body will also be explored.

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Development of Aqueous/Semi-Aqueous Cleaning Agent and its Field Application to Cleaning Process of Electronic Parts (수계/준수계 세정제의 개발 및 전자부품 세정공정 현장적용 연구)

  • Kim, Han-Seong;Cha, An-Jeong;Bae, Jae-Heum;Lee, Ha-Yeoul;Lee, Myung-Jin;Park, Byeong-Deog
    • Clean Technology
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    • v.10 no.2
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    • pp.61-72
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    • 2004
  • In this study, aqueous/semi-aqueous cleaning agents which consist of organic solvent, surfactant, cosurfactant, and water were developed by changing formulation parameters such as organic solvent type and contents, surfactant type and contents, and cosurfactant/surfactant(A/S) ratio, etc.. And physical properties and flux removal of the formulated cleaning agents have been evaluated. Also, the performance of oil-water separation from the rinse water contaminated during the cleaning process was evaluated for its recycling. The formulated cleaning agents in this work expected to have good penetration because of their low viscosity and low surface tension values of 30.2~32.5 dyne/cm. The flux removal with the terpene type cleaning agent was higher than that with hydrocarbon type cleaning agent and two commercial products (CPA(commercial product A), CPB(commercial product B)). And the performance of oil-water separation by gravity settling from the rinse water contaminated with formulated cleaning agent and soils was shown to be very good. The cleaning agents developed in this work were applied to surface mounting technology(SMT) cleaning process for manufacturing electronic parts at L electronic company. As a result, the newly developed cleaning agents showed two times better cleaning speed for removal of solder cream than the conventional ond containing ethanol and IPA(isopropyl alcohol). In addition, malodor and VOC problems generated by the previous organic cleaning agents have been solved in the manufacturing field through introduction of the non-volatile and environmental-friendly cleaning agents to the field.

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A Study on A Mathematical Formulation of Protection Ratio and Its Calculation for Fixed Radio Relay System with Diversity (다이버시티를 갖는 고정 무선 중계 시스템에 대한 보호비의 수학적 표현과 계산에 대한 연구)

  • Suh Kyoung-Whoan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.4 s.107
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    • pp.358-367
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    • 2006
  • In this paper, a mathematical formulation of protection ratio and its calculation method are suggested for a radio relay system with diversity techniques. The analysis of protection ratio and its physical meaning have been performed for the space or frequency diversity system, and in particular protection ratios are reviewed in terms of the parameters of diversity improvement factor, which comprises antenna gain, separation distance between antennas, frequency and its difference between carriers, and distance. As one of simulated results, the co-channel protection ratio of 60 dB is obtained for the space diversity system regarding 6.2 GHz, 60 km, 64-QAM, and 25 m between antennas, which gives 15 dB less than the co-channel protection ratio of the non-space diversity system. In addition, the co-channel protection ratio for the frequency diversity system gives 64 dB in case of frequency offset of 0.5 GHz under the same conditions as the space diversity system, which brings about 11 dB less than the co-channel protection ratio of non-frequency diversity system. In consequency, it is interesting to note that the space diversity system is less sensitive to interference in comparison to the frequency diversity system and provides better quality of service for a given interference.