• Title/Summary/Keyword: Deterioration factors

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A Development of Monitoring System for Evaluating Factors of Road Serviceability: Road Surface Temperature and Dynamic Loads (도로 공용성 평가를 위한 모니터링 시스템 개발: 노면온도 및 동적 하중)

  • Jo, Eun Se Sang;Jang, Junbong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.44 no.2
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    • pp.237-244
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    • 2024
  • Pavement management systems (PMS) provide procedures to quantify road serviceability based on pavement conditions such as cracks and plastic deformation and suggest proper maintenance methods. The deterioration of the road pavement is relevant to the time although the quantifications on road serviceability in PMS present road surface conditions at the evaluation. More systematic evaluation on road serviceability may need time-dependent factors of road environments and that can improve PMS. Rainfall, temperature and vehicle loads can be environmental factors for road serviceability evaluation. As no data are avablie that can link between road conditions and environmental road factors, we conducted experiments to suggest economical devices and methods to obtain relevant data. We used temperature sensors and accelerometers with Arduino to measure road surface temperature and dynamic loads and provide data to improve pavement serviceability evaluation.

A Study on the Influence of Harmonics in Power System Voltage on Arrester Diagnostics and its Compensation (피뢰기 열화진단에 있어 전원 고조파의 영향과 보정에 관한 연구)

  • Kim, Il-Kwon;Song, Jae-Yong;Han, Ju-Seop;Kil, Gyung-Suk;Rhyu, Keel-Soo;Cho, Han-Goo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.11
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    • pp.493-497
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    • 2005
  • This paper dealt with the influence of harmonic voltages on arrester diagnostics and its compensation method by using a designed Pspice arrester model. A pure sinusoidal voltage and its 3$^{rd}$ harmonic voltage were applied to the model, and the leakage current components were analyzed. The simulation results have shown that the peak value of resistive leakage current depends not only on the phase of the 3$^{rd}$ harmonic voltage but also on the magnitude of it. In this paper, an approximated 5$^{th}$ order polynomial formula by the Least-Square-Technique was derived, and correction factors which compensate the error caused by the 3$^{rd}$ harmonic voltage were calculated.

Intelligent Switching Control of the Pneumatic Artificial Muscle Manipulators

  • Ahn, Kyoung-Kwan;Thanh, TU Diep Cong
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.76-81
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    • 2004
  • Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

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Acute kidney injury and continuous renal replacement therapy in children; what pediatricians need to know

  • Cho, Myung Hyun;Kang, Hee Gyung
    • Clinical and Experimental Pediatrics
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    • v.61 no.11
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    • pp.339-347
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    • 2018
  • Acute kidney injury (AKI) is characterized by abrupt deterioration of renal function, and its diagnosis relies on creatinine measurements and urine output. AKI is associated with higher morbidity and mortality, and is a risk factor for development of chronic kidney disease. There is no proven medication for AKI. Therefore, prevention and early detection are important. Physicians should be aware of the risk factors for AKI and should monitor renal function in high-risk patients. Management of AKI includes optimization of volume status and renal perfusion, avoidance of nephrotoxic agents, and sufficient nutritional support. Continuous renal replacement therapy is widely available for critically ill children, and this review provides basic information regarding this therapy. Long-term follow-up of patients with AKI for renal function, blood pressure, and proteinuria is recommended.

Improvement of the Control Performance of Pneumatic Artificial Muscle Manipulators Using an Intelligent Switching Control Method

  • Ahn, Kyoung-Kwan;Thanh, TU Diep Cong
    • Journal of Mechanical Science and Technology
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    • v.18 no.8
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    • pp.1388-1400
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    • 2004
  • Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

A Study on the Milli-Forming of Crystalline Materials with Damage (결함을 고려한 결정 재료의 밀리 성형에 관한 연구)

  • 김용일;심경섭;이용신
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.120-126
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    • 2003
  • Finite element analysis model is suggested for analysis of milli-forming process, which forms milli-size products. Since the size of workpiece in a milli-forming process ranges from a few hundred micrometers to a few millimeters, microstructural changes such as the growth of micro-voids and the development of preferred orientation in a grain become crucial factors for the success of milli-forming. This analysis model incorporates anisotropy from deformation torture and deterioration of mechanical properties due to the growth of micro-voids. Applications of the proposed modeling to milli-forming are given and the results are carefully examined to understand the deformation characteristics such as texture development and damage evolution during extrusion/drawing of a milli-bar.

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Early Warning System for Desertification in I. R. of Iran (An Application of GIS and Remote Sensing)

  • Sepehr A.;BodaghJamali J.;Javanmard S.
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.189-192
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    • 2005
  • Desertification is one of the main global environmental phenomena. It has resulted in deterioration environment and poor economy, and imposed threat to the surviving environment of the overall mankind. Therefore, creating of methods for monitoring and estimate of risk desertification are necessary. Early warning system is one of important ways for monitoring and forecasting of desertification. Remote Sensing and GIS technology are as suitable tools and methods for early warning system. In this aim, we have evaluated of applications of remote sensing and GIS in monitoring and estimating desertification process (case study in Fars Province of Iran). In this research, we have considered erosion and vegetation cover parameters as main factors affecting in desertification process. The result shows that remote sensing and GIS technology could be useful in evaluation of desertification as one method for desertification early warning. Also, Results suggested that erosion and plant cover are affecting in develop the desertification process in study area.

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Resistance on the Magnesium Sulfate Attack of Mortars with Silica Fume (실리카흄 혼합 모르타르의 황산마그네슘 저항성)

  • 문한영;이승태;유지훈;최강식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.379-384
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    • 2002
  • The deterioration of concrete due to sulfate ions in various sulfate environments such as groundwater, soil and seawater is one of important factors degrading the durability of concrete structure. The aim of this paper is to evaluate on the magnesium sulfate alttack resistance of mortars with silica fume. In this study, compressive strength loss and length change of prismatic mortars, containing silica fume, immersed in 5% magnesium sulfate solution for 270 days were investigated. Additionally, paste powders with same binder were used to observe reactants of cement matrices through the instrumental analysis such as XRD, SEM and MIP. Results obtained from this study indicate that the greater damaging effects of the magnesium soulution are due to the decomposition of the C-S-H gel to M-C-S-H.

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An Experimental Study on the Salt Resistance Properties with Concrete Materials under Marine Environment (해양환경에 노출시킨 콘크리트의 내염성능 평가)

  • Ko Jeong-Jae;Kim Young-Ung;Kim Dong-Chul;Shin Do-Chul;Kim Sang-Yong;Byun Dae-Bong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.790-793
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    • 2004
  • The factors influencing concrete deterioration in marine environment can be generally divided into the physical and chemical action. The physical attack due to drying and wetting would increase the internal stress of concrete. The chemical attack resulting from the diffusion of ions$(i,e,\;Cl^-,SO_4^{2-},Mg^+)$ from seawater through the pores in concrete. The objective of this study is to evaluate corrosion characteristics of steel when using the various concrete materials under marine exposure environment. After 3 years of exposure, concrete specimen incorporating $40\%$ blast-furnace slag as replacement for type I cement with low w/c ratio of 0.42 and using the inhibitor shows excellent performance.

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The Physical Therapy Approaches on Post-Mastectomy (유방절제술 후 물리치료적 접근)

  • Jeon, You-Jin
    • Journal of Korean Physical Therapy Science
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    • v.7 no.2
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    • pp.439-457
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    • 2000
  • The causes, risk factors and sequelae of mastectomy were studied, and the physical therapy approaches on post-mastectomy was discussed in this study. It was found that the patients taken mastectomy have experienced pins and needles in muscle, weakening of muscle, pains, deterioration of motion in joint region and activities of daily living, psychiatric sequelae, and etc even after the conservertive therapies like the chemical therapy, radiotherapy, immunotherapy, and hormone therapy. However, few study on the physical therapy approaches for patients with breast cancer has been carried in Korea at present. The followings were proposed as the physical therapy approaches. 1. Shoulder joint motion approach to relax the limit of range of motion 2. Control of breathing exercise for dealing with removal of the pectorailis muscle 3. Method to reduce the edema of arms for tackling the cut of lymph node 4. Method to reduce pains, pins and needles 5. Support home exercise program after discharging from hospital, sexual life and pregnancy, and activities of daily living training method.

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