• Title/Summary/Keyword: Laser

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Design and Implementation of an Indoor Particulate Matter and Noise Monitoring System (실내 미세먼지 및 소음 모니터링 시스템 설계 및 구현)

  • Cho, Hyuntae
    • IEMEK Journal of Embedded Systems and Applications
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    • v.17 no.1
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    • pp.9-17
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    • 2022
  • As the COVID-19 pandemic situation worsens, the time spent indoors increases, and the exposure to indoor environmental pollution such as indoor air pollution and noise also increases, causing problems such as deterioration of human health, stress, and discord between neighbors. This paper designs and implements a system that measures and monitors indoor air quality and noise, which are representative evaluation criteria of the indoor environment. The system proposed in this paper consists of a particulate matter measurement subsystem that measures and corrects the concentration of particulate matters to monitor indoor air quality, and a noise measurement subsystem that detects changes in sound and converts it to a sound pressure level. The concentration of indoor particulate matters is measured using a laser-based light scattering method, and an error caused by temperature and humidity is compensated in this paper. For indoor noise measurement, the voltage measured through a microphone is basically measured, Fourier transform is performed to classify it by frequency, and then A-weighting is performed to correct loudness equality. Then, the RMS value is obtained, high-frequency noise is removed by performing time-weighting, and then SPL is obtained. Finally, the equivalent noise level for 1 minute and 5 minutes are calculated to show the indoor noise level. In order to classify noise into direct impact sound and air transmission noise, a piezo vibration sensors is mounted to determine the presence or absence of direct impact transmitted through the wall. For performance evaluation, the error of particulate matter measurement is analyzed through TSI's AM510 instrument. and compare the noise error with CEM's noise measurement system.

A Study on the Reverse Engineering and Wear Analysis for Remanufacturing Planner Miller (플래너 밀러 재제조를 위한 역설계 및 마모 분석에 관한 연구)

  • Choi, Doo-Han;Kong, Seok-Hwan;Byeon, Jeong-Won;Kim, Tae-Woo;Hong, Dae-Sun
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.6_2
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    • pp.1103-1110
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    • 2022
  • The old machine tools that have been used for a long time cause both increase in defective rate and decrease in productivity compared to new machines due to wear and failure of their components. In order to improve productivity and quality of machined components through remanufacturing, it is necessary to analyze the wear and failure of major components of old machine tools. In this study, the process for reverse engineering is designed for the remanufacture of planner millers, which belong to a very large machine tool. Also, the suitability of the designed process is verified through the analysis of the selected remanufactured components. In the first step of the process, some major components of the aging planner miller are scanned using a 3D laser scanner. In the next step, reverse engineering is performed using the data obtained through 3D scanning. Finally, wear and failure analysis is performed by comparing the reverse engineering data with the scan data. As a result, this reverse design and wear analysis can complement the insufficient design database and reduce costs in the maintenance of remanufactured products.

Tribological Characteristics of DLC-Coated Part in Compressor (컴프레서 부품의 DLC코팅 적용에 따른 트라이볼로지적 특성 연구)

  • Yoon, Joo-Yong;Seo, Kuk-Jin;Han, Jae-Ho;Chun, Jihwan;Song, Jiyoung;Koh, Youngdeog;Nam, Jahyun;Kim, Seonkyo;Kim, Dae-Eun
    • Tribology and Lubricants
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    • v.38 no.1
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    • pp.8-14
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    • 2022
  • Amorphous carbon (a-C) has excellent wear resistance and, therefore is used as a coating to protect numerous mechanical components to prolong their lifetimes. Among the a-C coatings, diamond-like carbon (DLC) and DLC-containing silicon (Si-DLC) receive extensive attention owing to their enhanced wear resistance and low frictional characteristics. In this study, the friction and wear characteristics of DLC and Si-DLC coatings are analyzed. For comparative analysis, DLC-coated and Si-DLC-coated vanes are utilized with the counterpart of a roller for the friction tests. Since the lubricated mechanical components are generally vulnerable to wear when a lubricant film does not form properly, friction tests are conducted under boundary lubrication conditions to promote wear. A cylinder-on-cylinder type tribometer is used to perform the friction tests with various normal load conditions. After the friction test, a 3D laser confocal microscope is used for quantifying the wear volume to calculate the wear rate of each specimen. Consequently, the DLC-coated specimen shows a lower coefficient of friction (COF) and wear rate than the specimen without the coating, while the Si-DLC coating shows a higher COF than the bare specimen. The results of this study are expected to contribute to improving the efficiency and reliability of compressors.

A Study on the Quality Control Plan for Bridge Pavement using drones (드론을 활용한 교면포장 품질관리 방안에 관한 연구)

  • Song, Mihwa;Gil, Heungbae
    • Journal of the Korea Convergence Society
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    • v.13 no.5
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    • pp.1-8
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    • 2022
  • In Korea, drones, which are at the core of the 4th industrial revolution, are used to promote Korean New Deal policies to digitalize the SOC. Overseas, the use of convergence sensors, such as thermal imaging cameras, on drones is increasing in various industrial fields. In this research, to improve pavement quality in highway bridge pavement construction, a thermal imaging camera was mounted on a drone to measure and verify the temperature of the pavement work section. Using a laser thermometer allows the partial measurement of pavement temperature. It was confirmed that the proposed method allows not only real-time temperature monitoring of the whole pavement work section but also uniformity verification by checking temperature distribution. The proposed method has the potential to control highway pavement quality and enable quick decision-making on traffic opening times by reducing the possibility of misjudging road opening times(pavement surface temperature ≦ 40℃).

Optimal Processing for Peptic Hydrolysate from Flounder Skin and Its Skincare Function (광어껍질을 활용한 펩신가수분해물 제조공정 최적화와 피부건강 기능성)

  • Kang, You-an;Jin, Sang-Keun;Ko, Jonghyun;Choi, Yeung Joon
    • Journal of Marine Bioscience and Biotechnology
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    • v.14 no.1
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    • pp.9-24
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    • 2022
  • Low-molecular weight peptides derived from fish collagen exhibit several bioactivities, including antioxidant, antiwrinkle, antimicrobial, antidiabetic, and antihypertension effects. These peptides are also involved in triglyceride suppression and memory improvement. This study aimed to investigate the optimal processing condition for preparing low-molecular weight peptides from flounder skin, and the properties of the hydrolysate. The optimal processing conditions for peptic hydrolysis were as follows: a ratio of pepsin to dried skin powder of 2% (w/w), pH of 2.0, and a temperature of 50℃. Peptic hydrolysate contains several low-molecular weight peptides below 300 Da. Gly-Pro-Hyp(GPHyp) peptide, a process control index, was detected only in peptic hydrolysate on matrix-assisted laser desorption/ionization-time-of-flight(MALDI-TOF) spectrum. 2,2'-azinobis-(3-3-ethylbenzothiazolline-6- sulfonic acid(ABTS) radical scavenging activity of the peptic hydrolysate was comparable to that of 1 mM ascorbic acid, which was used as a positive control at pH 5.5, whereas collagenase inhibition was five times higher with the peptic hydrolysate than with 1 mM ascorbic acid at pH 7.5. However, the tyrosinase inhibition ability of the peptic hydrolysate was lower than that of arbutin, which was used as a positive control. The antibacterial effect of the peptic hydrolysate against Propionibacterium acne was not observed. These results suggest that the peptic hydrolysate derived from a flounder skin is a promising antiwrinkle agent that can be used in various food and cosmetic products to prevent wrinkles caused by ultraviolet radiations.

Measurement of Tree Height and Diameter Using Terrestrial Laser Scanner in Coniferous Forests (지상 LiDAR를 활용한 침엽수림의 수고 및 흉고직경 측정)

  • Ko, Byung-Jun;Park, Se-Ik;Park, Hee-Jung;Lee, Sang-Hyun
    • Journal of Environmental Science International
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    • v.31 no.6
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    • pp.479-490
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    • 2022
  • This study was to evaluate the utilization of terrestrial light detection and ranging for forest inventory in coniferous forests. Heights and diameter of the stand trees were measured manually using the traditional measurement method and the method using terrestrial LiDAR. The results of two methods were compared and analyzed to evaluate accuracy and feasibility. The terrestrial LiDAR used fixed and handy types to compare the accuracy between different operational methods. Comparative analyses used a paired t-test and Bland-Altman plot analysis. In the case of tree heights, the average of difference between the traditional method and terrestrial LiDAR for each plot was 0.81 m, -0.07 m, and 0.13 m for fixed type; 2.88 m, 1.19 m, and 0.93 m for the handy type. In the case of tree diameter at breast height, the average value of the difference between traditional methods and terrestrial LiDAR for each plot was 0.13 cm, -0.66 cm, and -0.03 cm for fixed type; 2.36 cm, 2.13 cm, and 1.92 cm for the handy type. The values from the method using the fixed type was highly consistent with that using the traditional measurement methods; the average difference was closer to zero. The crown density influences the precision of the height measurement using terrestrial LiDAR in coniferous forests. Therefore, future studies should focus on verifying the accuracy of terrestrial LiDAR in forests and on expanding the utilization of terrestrial LiDARs according to their operational methods.

STRATEGIC RESEARCH AT ORNL EOR THE DEVELOPMENT OF ADVANCED COATED CONDUCTORS: PART - II

  • Paranthama, M. Parans;Aytug, T.;Sathyamurthy, S.;Zhai, H.Y.;Christen, H.M.;Martin, P.M.;Goyal, A.;Christen, D.K.;Kroeger, D.M.
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.340-340
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    • 2002
  • In an effort to develop alternative single buffer layer technology for YBa$_2$Cu$_3$O$_{7-{\delta}}$ (YBCO) coated conductors, we have investigated both LaMnO$_3$, (LMO) and La$_2$Zr$_2$O$_{7}$ (LZO) as potential buffer layers. High-quality LMO films were grown directly on textured Ni and Ni-W (3%) substrates using rf magnetron sputtering. Highly textured LZO buffers were grown on textured Ni substrates using sol-gel alkoxide processing route. YBCO films were then grown on both LMO and LZO buffers using pulsed laser deposition. Detailed X-ray studies have shown that YBCO films were grown on both LMO and LZO layers with a single epitaxial orientation. A high J$_{c}$ of over 1 MA/cm$^2$ at 77 K and self-field was obtained on YBCO films grown on both LMO-buffered Ni or Ni-W substrates, and also on LZO-buffered Ni substrates. We have identified LaMnO$_3$ as a good diffusion barrier layer for Ni and it also provides a good template for growing high current density YBCO films. Similarly we have also demonstrated the growth of high J$_{c}$ YBCO films on all solution buffers. We will discuss in detail about our buffer deposition processes. processes.s.s.s.s.

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Effects of hairline treatment on surface blackening and thermal diffusion of Zn-Al-Mg alloy-coated steel sheet (Zn-Al-Mg 합금도금강판의 헤어라인 처리가 표면흑색화 및 열확산도에 미치는 영향)

  • Jin Sung Park;Duck Bin Yun;Sang Heon Kim;Tae Yeob Kim;Sung Jin Kim
    • Journal of the Korean institute of surface engineering
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    • v.56 no.1
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    • pp.69-76
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    • 2023
  • The effects of hairline treatment on surface blackening and thermal diffusion behaviors of Zn-Al-Mg alloy coated steel sheet were evaluated by the three-dimensional surface profiler and laser-flash technique. The metallographic observation of coating damages by hairline treatments showed that several cracks were initiated and propagated along the interface between primary Zn/eutectic phases. As the hairline processing became more severe, the crack occurrence frequency in eutectic phase of coating layer and the surface roughness increased, which had a proportional relationship with the level of blackening on the coating surface. In addition, the higher interfacial areas of the blackened coating surface, caused by the hairline process, led to an increase in thermal diffusivity and conductivity of the coated steel sheet. On the other hand, when the coating damage by hairline treatment was excessive and the steel substrate was exposed, there was little difference between the thermal diffusivity/conductivity of the untreated sample though the blackening degree was higher than that of untreated sample. This work suggests that the increase in the surface areas of the coating layer without exposure to steel substrate through hairline treatment can be one of the effective technical strategies for the development of Zn-Al-Mg alloy coated steel sheets with higher blackening level and thermal diffusivity.

Analysis of Domestic and Foreign Research Trends on the Korean Medical Treatment of Avascular Necrosis of the Femoral Head (대퇴골두 무혈성 괴사의 한의학적 치료에 대한 국내·외 연구동향 분석)

  • Eun Sang Park;Hyeon Ho Hwang;Ki Hyun Park;Jun Hyo Bae;Ji Eun Koo;Kyu Hyun Hwang;Jun Hyuk Kang
    • Journal of Korean Medicine Rehabilitation
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    • v.33 no.1
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    • pp.47-59
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    • 2023
  • Objectives This paper is an analysis of domestic and foreign trends for the Korean medical treatment of avascular necrosis of the femoral head. Methods Domestic and foreign databases were searched and analyzed for Korean medical treatment interventions, research types, and treatment effects for avascular necrosis of the femoral head. Results There were 10 case reports in Korea, 2 case reports and 3 randomized controlled studies abroad. A total of 12 treatment interventions were used, and the types include acupuncture, herbal medicine, phamacopunture, electroacupuncture, cupping, physical therapy, chuna, acupotomy, moxibustion, warm acupuncture, laser acupuncture, and motion style treatment. As for the evaluation index, visual analogue scale, range of motion and harris hip score were the most common with 7 cases each. Conclusions Through this study, it was possible to understand the trends of domestic and foreign research on the treatment of avascular necrosis of the femoral head with Korean medicine. However, due to the small number of literature and no randomized control studies in Korea, treatment evidence is insufficient. It is considered that further research is needed in the future.

Utilization of sensor-based on-site measurement data to improve the accuracy of reservoir turbid water simulation (저수지 탁수모의 정확도 개선을 위한 센서기반 현장 계측자료 활용)

  • Jong Min Kim;Gwang Soo Kim;Se Woong Chung;Kim, Young Do
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.136-136
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    • 2023
  • 우리나라의 강우 특성은 하절기에 집중되어 있으며 최근 이상강우와 기상이변에 따른 집중호우 발생으로 여를철 탁수 문제 발생 빈도가 높아지고 있는 추세이다. 과거 '02년 태풍 루사', '03년 태풍 매미', '06년 에위니아'부터 20년 마이삭, 하이선과 같은 태풍 및 장마에 의해 탁수 유입이 급증되어 수중 탁도가 높아지며 저수지 탁수 문제가 발생하였다. 특히 우리나라 경우 하천 및 저수지에서 물 사용량의 대부분을 이용하고 있기에 탁수 문제가 장기화 될 시 댐 하류 지역의 농업, 공업, 수생태 등 사회적, 비용적, 환경적 문제를 발생시킨다. 이러한 문제를 파악, 대응을 위한 탁수 모의에 대한 연구가 활발히 진행되고 있다. 탁수를 모의하기 위해서는 유량, 수온, SS, 탁도 데이터가 필요하며 이를 위해 국가측정망에서 하천 및 댐 저수지 내 SS를 측정하여 탁수를 측정 하고 있다. 하지만 현재 측정의 경우 채수를 통한 점단위의 측정으로 데이터 해상도가 낮다는 한계점이 있다. 이러한 데이터 취득의 한계로 기존 조사를 통한 탁도-SS 관계식을 통해 탁수를 예측하고 있으나 과거 2003년 이후 자료를 바탕으로 산정된 식으로 불확도가 존재한다. 탁수 모의 정확도 개선을 위한 데이터 해상도 및 탁도-SS 관계식 문제를 해결 하기 위해 기존 데이터 분석을 통한 미계측 기간에 대한 보간을 필요로 하며 현장 계측을 통한 탁도, SS 자료를 취득하여 탁도-SS 관계식을 최신화 할 필요가 있다. 따라서, 본 연구에서는 탁도를 측정 센서 YSI와 SS 측정센서 레이저부유사측정기(LISST: Laser In-Situ Scattering and Transmissometry)를 활용하여 자료를 취득하고 탁도-SS 산정식을 최신화 하였다. 또한 기존 국가 수질 측정망 데이터 및 기상 자료 데이터를 취득하여 데이터 분석을 통해 미계측 기간에 대한 데이터를 보간하여 탁수 모의 입력자료를 개선하였고 이를 기반으로 탁수 모의 정확도를 개선하고자 하였다.

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