• Title/Summary/Keyword: Load-cell

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Biomechanical Comparison of Inter-fragmentary Compression Pressures : Lag Screw versus Herbert Screw for Anterior Odontoid Screw Fixation

  • Park, Jin-Woo;Kim, Kyoung-Tae;Sung, Joo-Kyung;Park, Seong-Hyun;Seong, Ki-Woong;Cho, Dae-Chul
    • Journal of Korean Neurosurgical Society
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    • v.60 no.5
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    • pp.498-503
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    • 2017
  • Objective : The purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw. Methods : We compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws. Results : The mean compression pressures of the 40- and 45-mm long cannulated lag screws were $50.48{\pm}1.20N$ and $53.88{\pm}1.02N$, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was $52.82{\pm}2.17N$, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure ($60.68{\pm}2.03N$) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively). Conclusion : Our results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

Development of the Dredged Sediments Management System and Its Managing Criteria of Debris Barrier (사방댐 준설퇴적물 관리시스템 개발 및 관리기준 제안)

  • Song, Young-Suk;Yun, Jung-Mann;Jung, In-Keun
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.4
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    • pp.267-275
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    • 2018
  • The dredged sediment management system was developed to have an objective, quantitative and scientific decision for the optimum removal time of dredged sediments behind debris barrier and was set up at the real site. The dredged sediment management system is designed and developed to directly measure the dredged sediments behind debris barrier in the field. This management system is composed of Data Acquisition System (DAS), Solar System and measurement units for measuring the weight of dredge sediments. The weight of dredged sediments, the water level and the rainfall are measured in real time using the monitoring sensors, and their data can be transmitted to the office through a wireless communication method. The monitoring sensors are composed of the rain gauge to measure rainfall, the load cell system to measure the weight of dredged sediments, and water level meter to measure the water level behind debris barrier. The management criteria of dredged sediments behind debris barrier was suggested by using the weight of dredged sediments. At first, the maximum weight of dredged sediments that could be deposited behind debris barrier was estimated. And then when 50%, 70% and 90% of the maximum dredged sediments weight were accumulated behind debris barrier, the management criteria were divided into phases of Outlooks, Watch and Warning, respectively. The weight of dredged sediments can be monitored by using the dredged sediment management system behind debris barrier in real time, and the condition of debris barrier and the removal time of dredged sediments can be decided based on monitoring results.

Antibacterial and Antiviral Activities of Multi-coating Polyester Textiles (다중 코팅 폴리에스터 섬유 여재의 항균 및 항바이러스 특성)

  • Ko, Sangwon;Lee, Jae-Young;Park, Duckshin
    • Applied Chemistry for Engineering
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    • v.33 no.4
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    • pp.444-450
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    • 2022
  • The effect of coated polyester (PET) textiles with metal oxide, chitosan, and copper ion on the antibacterial and antiviral activities was evaluated to investigate the applicability of multi-coated PET textiles as antiviral materials. Compared to coated PETs with a single agent, multi-coated PETs reduced the loading amount of coating materials as well as the contact time with bacteria for a bacterial cell number of < 10 CFU/mL, which was not detectable with the naked eyes. Metal oxides generate reactive oxygen species (ROS) such as free radicals by a catalytic reaction, and copper ions can promote contact killing by the generation of ROS. Chitosan not only enhanced antibacterial activities due to amine groups, but enabled it to be a template to load copper ions. We observed that multi-coated PET textiles have both antibacterial activities for E. coli and S. aureus and antiviral efficiency of more than 99.9% for influenza A (H1N1) and SARS-CoV-2. The multi-coated PET textiles could also be prepared via a roll-to-roll coating process, which showed high antiviral efficacy, demonstrating its potential use in air filtration and antiviral products such as masks and personal protective equipment.

One-health Approach in the Post-COVID-19 Era: Focusing on Animal Infection (One-health 관점에서 본 Post-COVID-19 시대의 동물 감염)

  • Hye-Jeong Jang;Sun-Nyoung Yu;O-Yu Kwon;Soon-Cheol Ahn
    • Journal of Life Science
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    • v.33 no.2
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    • pp.199-207
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    • 2023
  • To prepare for the threat of a future epidemic in the post-COVID-19 era, research based on the one-health concept (i.e., the health of humans, animals, and the environment as "one") is essential. Cross-species infections are being identified as a result of the high infection rate and viral load of SARS-CoV-2 in humans. The possibility of transmission of SARS-CoV-2 from humans to mink has been determined. In addition, the transmission of SARS-CoV-2 from humans to cats through contact has been considered possible. The data so far show that livestock and poultry are less likely to be infected with SARS-CoV-2. However, if infections are established through a new mutation, the resulting diseases are expected to have enormous ripple effects on various fields, such as human food security, the economy, and trade. In addition, there are concerns about the endemic prospect of SARS-CoV-2 and the high accessibility of companion animals. This is because the evolution of the virus likely occurs in animal hosts. Once SARS-CoV-2 is established in other species, they might serve as intermediate hosts for the re-emergence of the virus in the human population. Thus, it is necessary to ensure a rapid response to future outbreaks by accumulating research data on the animal infection of SARS-CoV-2. These data can have implications for the development of animal models for vaccines and therapeutics against SARS-CoV-2. Therefore, in this study, epidemiological reviews were analyzed, and response strategies against SARS-CoV-2 infection in animals were presented using the One-health approach.

Effect of Voltage Range and Number of Activation Cycles in the Activation Process of a Polymer Electrolyte Fuel Cell (고분자 전해질 연료전지의 활성화과정에서 전압 범위 및 활성화 횟수의 영향)

  • Donggeun Yoo;Sohyeong Oh;Sunggi Jung;Jihong Jeong;Kwonpil Park
    • Korean Chemical Engineering Research
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    • v.61 no.1
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    • pp.58-61
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    • 2023
  • The activation process is essential for PEMFC to improve initial performance. The most commonly used activation method is a voltage change (load change) method, which may accompany degradation of the electrode catalyst if excessively performed. In many activation processes, the voltage change range is activated in a wide range from 0.4 V to OCV, and research is needed to reduce the voltage change range in order to prevent electrode catalyst degradation and shorten the activation time. Therefore, in this study, when the activation voltage range was 0.4~0.6 V, 0.4~0.8 V, and 0.4~OCV, we tried to research and develop an effective activation method by analyzing the performance and characteristics of the electrode and polymer membrane. The performance improvement was the lowest in the activation with a wide voltage range from 0.4 V to the highest OCV, and the performance decreased by 10% when activated for 56 cycles. The 0.4~0.6 V activation cycle showed the highest performance improvement up to 20% and the smallest decrease in performance due to overactivation, indicating that it is optimal method.

Characteristics of Rigid-Soft Particle Mixtures with Size Ratio (입자크기비에 따른 강-연성 혼합재의 공학적 특성)

  • Lee, Chang-Ho;Yoon, Hyung-Koo;Kim, Rae-Hyun;Lee, Woo-Jin;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.24 no.8
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    • pp.125-135
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    • 2008
  • Rigid-soft particle mixtures, which consist of sand and rubber, are investigated for the understanding of the stress-deformation and elastic moduli. Specimens are prepared with various size ratio sr between sand and rubber particles, and different volumetric sand fraction sf. Small strain shear waves are measured under $K_o$-loading condition incorporated with the stress-deformation test by using oedometer cell with bender elements. The stress-deformation and small strain shear wave characteristics of rigid-soft particle mixtures show the transition from a rigid particle behavior regime to a soft particle behavior regime under fixed size ratio. A sudden rise of $\Lambda$ factor and the maximum value of the $\zeta$ exponent in $G_{max}=\;{\Lambda}({\sigma}'_{o}/kPa)^{\zeta}$ are observed at $sf\;{\approx}\;0.4{\sim}0.6$ regardless of the size ratio sf. Transition mixture shows high sensitivity to confining stress. The volume fraction for the minimum porosity may depend on the applied stress level in the rigid-soft particle mixtures because the soft rubber particles easily distort under load. In this experimental study, the size ratio and volumetric sand fraction are the important factors which determine the behavior of rigid and soft particle mixtures.

Research on soil composition measurement sensor configuration and UI implementation (토양 성분 측정 센서 구성 및 UI 구현에 관한 연구)

  • Ye Eun Park;Jin Hyoung Jeong;Jae Hyun Jo;Young Yoon Chang;Sang Sik Lee
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.17 no.1
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    • pp.76-81
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    • 2024
  • Recently, agricultural methods are changing from experience-based agriculture to data-based agriculture. Changes in agricultural production due to the 4th Industrial Revolution are largely occurring in three areas: smart sensing and monitoring, smart analysis and planning, and smart control. In order to realize open-field smart agriculture, information on the physical and chemical properties of soil is essential. Conventional physicochemical measurements are conducted in a laboratory after collecting samples, which consumes a lot of cost, labor, and time, so they are quickly measured in the field. Measurement technology that can do this is urgently needed. In addition, a soil analysis system that can be carried and moved by the measurer and used in Korea's rice fields, fields, and facility houses is needed. To solve this problem, our goal is to develop and commercialize software that can collect soil samples and analyze the information. In this study, basic soil composition measurement was conducted using soil composition measurement sensors consisting of hardness measurement and electrode sensors. Through future research, we plan to develop a system that applies soil sampling using a CCD camera, ultrasonic sensor, and sampler. Therefore, we implemented a sensor and soil analysis UI that can measure and analyze the soil condition in real time, such as hardness measurement display using a load cell and moisture, PH, and EC measurement display using conductivity.

Validation of Launch Vibration Isolation Performance of the Passive Vibration Isolator for the Scientific Payload BioCabinet for CAS500-3 (차세대중형위성 3호 과학탑재체 바이오캐비넷용 수동형 진동절연기의 발사진동 저감성능 검증)

  • Dong-Jae Seo;Yeon-Hyeok Park;Young-Jin Lee;Ji-Seung Lee;Kyung-Hee Kim;Soon-Hee Kim;Chan-Hum Park;Hyun-Ung Oh
    • Journal of Aerospace System Engineering
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    • v.18 no.4
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    • pp.81-88
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    • 2024
  • The payload BioCabinet of CAS500-3 is designed for 3D stem cell differentiation, culture, and analysis utilizing bio 3D printing techniques in space. The 3D printing technique was initially developed for orbital use; however, it lacks separate validation for extreme launch vibration environments, necessitating a design that mitigates the launch load on the payload. This paper proposes a passive vibration isolator with a low-stiffness elastic support structure and high damping characteristics to reduce the launch loads affecting the BioCabinet. We explore the high-damping characteristics through the superelastic effects of SMA (Shape Memory Alloys) and a multi-layered structure incorporating viscoelastic tape. The effectiveness of the proposed vibration isolation system was confirmed via launch vibration tests on a qualification model.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

BIOMECHANICS OF ABUTMENTS SUPPORTING REMOVABLE PARTIAL DENTURES UNDER UNILATERAL LOADING

  • Kim, Seong-Kyun;Heo, Seong-Joo;Koak, Jai-Young;Lee, Jeong-Taek;Roh, Hyun-Ki;Kim, Hyo-Jin;Lee, Seok-Hyung;Lee, Joo-Hee
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.6
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    • pp.753-759
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    • 2007
  • Statement of problem. In distal extension removable partial denture, the preservation of health of abutment teeth is very important, but abutment teeth are subjected to unfavorable stress under unilateral loading specially. Purpose. The purpose of this study was to investigate the biomechanical effects of mandibular removable partial dentures with various prosthetic designs under unilateral loading, using strain gauge analysis. Material and methods. Artificial teeth of both canines were anchored bilaterally in a mandibular edentulous model made of resin. Bilateral distal extension removable partial dentures with splinted and unsplinted abutments were fabricated. Group 1: Clasp-retained mandibular removable partial denture with unsplinted abutments Group 2: Clasp-retained mandibular removable partial denture with splinted abutments by 6-unit bridge. Group 3: Bar-retained mandibular removable partial denture Strain gauges were bonded on the labial plate of the mandibular resin model, approximately 2 mm dose to the abutments. Two unilateral vertical experimental loadings (30N and 100N) were applied subsequently via miniature load cell that were placed at mandibular left first molar region. Strain measurements were performed and simultaneously monitored from a computer connected to data acquisition system. For within-group evaluations, t-test was used to compare the strain values and for between-group comparisons, a one-way analysis of variance (ANOVA) was used and Tukey test was used as post hoc comparisons. Results. The strain values of group 1 and 2 were tensile under loadings. In contrast, strain values of group 3 were compressive in nature. Strain values increased as the applied load in increased from 30N to 100N (p<.05) except for right side in group 1. Under 30N loading, in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 100N loading in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 30N loading, group 2 and 3 showed higher strain values in right side than in left side. Under 100N loading, right side strain values were higher than left side ones for all groups. Conclusion. Splinting of two isolated abutments by bridge reduced the peri-abutment strain in comparison with unsplinted abutments under unilateral loading. Bar-retained removable partial denture showed the lowest strain of three groups, and compressive nature.