• Title/Summary/Keyword: glass fibre

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A Study on Technology of Waterproofing of the Concrete Structure Which Used Soft FRP Resin and Square Groove Cutting Technique (연질 FRP 수지와 정방형 홈 컷팅 기술을 이용한 콘크리트 구조물의 방수기술에 관한 연구)

  • Lee, Hyung-Jun;Choi, Sung-Min;Kim, Sung-Sik;Ahn, Sang-Ku;Cho, Ah-Hyung;Oh, Sang-Keun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.597-600
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    • 2008
  • In this study the reason which researches the feature of the exposure type waterproofing it uses the technique of the soft FRP it uses the soft unsaturated polyester and the square groove cutting technique with respects and solves the interface separate problem because of the rigid FRP it is used with the repairs and retrofit materials it is caused by in adhesion of concrete insufficiency. The feature of this technique was the dispersion and the reinforcement of the fatigue stress due to the integration behavior and the reinforcement due to the glass-fibre of the concrete due to the soft FRP resin and, it investigated the crack appearance confrontation of concrete and the cohesion stability of the concrete due to the square groove cutting technique with importance. The result of research when it applies the soft FRP with the exposure type waterproofing, is judged with the fact that it will be able to expect a bulge resistance confrontation and creak confrontation ability and cohesion stability improvement.

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Vibration control of small horizontal axis wind turbine blade with shape memory alloy

  • Mouleeswaran, Senthil Kumar;Mani, Yuvaraja;Keerthivasan, P.;Veeraragu, Jagadeesh
    • Smart Structures and Systems
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    • v.21 no.3
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    • pp.257-262
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    • 2018
  • Vibrational problems in the domestic Small Horizontal Axis Wind Turbines (SHAWT) are due to flap wise vibrations caused by varying wind velocities acting perpendicular to its blade surface. It has been reported that monitoring the structural health of the turbine blades requires special attention as they are key elements of a wind power generation, and account for 15-20% of the total turbine cost. If this vibration problem is taken care, the SHAWT can be made as commercial success. In this work, Shape Memory Alloy (SMA) wires made of Nitinol (Ni-Ti) alloys are embedded into the Glass Fibre Reinforced Polymer (GFRP) wind turbine blade in order to reduce the flapwise vibrations. Experimental study of Nitinol (Ni-Ti) wire characteristics has been done and relationship between different parameters like current, displacement, time and temperature has been established. When the wind turbine blades are subjected to varying wind velocity, flapwise vibration occurs which has to be controlled continuously, otherwise the blade will be damaged due to the resonance. Therefore, in order to control these flapwise vibrations actively, a non-linear current controller unit was developed and fabricated, which provides actuation force required for active vibration control in smart blade. Experimental analysis was performed on conventional GFRP and smart blade, depicted a 20% increase in natural frequency and 20% reduction in amplitude of vibration. With addition of active vibration control unit, the smart blade showed 61% reduction in amplitude of vibration.

A Study on the Nutritional Assessment of Early Childhood Using Mid-Upper-Arm Circumference (상박위(上膊圍)에 의(依)한 성장기(成長期) 아동(兒童)에 영양상태(營養狀態)의 판정(判定)에 관(關)한 연구(硏究))

  • Tchai, B.S.;Nam, Y.K.;Chung, Y.J.
    • Journal of Nutrition and Health
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    • v.8 no.4
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    • pp.9-14
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    • 1975
  • Growth retardation and a variable degree of body disproportion are recognized features of malnutrition, and mild and moderate protein-calorie malnutrition(PCM). Among the various body measurements suggested to assess the prevalence of all grades of PCM as judged by growth retardation and by body disproportion, the 'mid-upper-arm circumference'-abbreviated to 'arm-circumference' has been suggested as a potential useful simple field index for the assessment of PCM showing that the measurement would give composite information simultaneously on three important effects on PCM-deficit in the muscle protein reservoirs, availability of calorie stores in the form of subcutaneous fat, and growth failure. And this is selected because of its easy accessibility, and less involvement with clinical edema. This study is conducted to make a comparison between the percentage of Korean weight for age standards and the percentage of mid-upper-arm circumference for age standards of 175 preschool children aged $3{\sim}72$ months who are selected among the low-income residents in Seoul. In this study, a comparison is made between the results obtained by expressing the observed weight of the child as a percentage of Korean standard, referred to as 'weight-for-age' and the observed arm-circumference expressed as a percentage of the age-specific arm standard of Jelliffe, referred to as 'arm-for-age'. All the measurements were taken following the techniques described by Jelliffe. The left mid upper arm was measured using a glass-fibre tape and the Fairbanks Morse beam balance was used for weighing. 80% level of weight for age Korean standard and 85% level of arm for are Jelliffe standard were used as an upper borderline limit for PCM. Comparing the 80% weight-for-age and the 85% arm-for-age standard as an upper limit for PCM, for children aged $3{\sim}72$ months, results in 84.6% agreement with the sensitivity of 86.4% and its specificity of 83.5%. If arm circumference alone had been measured and judgement made on this basis, then only 5.1% of the children would have been 'wrongly' classified. And there is a moderately close correlation between arm circumference and weight for age as the data in Table 4 shows. The problem therefore lies in the standard for arm circumference in normal children and in determining what is the lower limit of normal. Once this is clearly difined, one can rely more confidently on arm circumference measurements alone for the nutritional assessment of early childhood.

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NIRS Analysis of Liquid and Dry Ewe Milk

  • Nunez-Sanchez, Nieves;Varo, Garrido;Serradilla-Manrique, Juan M.;Ares-Cea, Jose L.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1251-1251
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    • 2001
  • The routine analysis of milk chemical components is of major importance both for the management of animals in dairy farms and for quality control in dairy industries. NIRS technology is an analytical technique which greatly simplifies this routine. One of the most critical aspects in NIRS analysis of milk is sample preparation and analysis modes which should be fast and straightforward. An important difficulty when obtaining NIR spectra of milk is the high water content (80 to 90%) of this product, since water absorbs most of the infrared radiation, and, therefore, limits the accuracy of calibrating for other constituents. To avoid this problem, the DESIR system was set up. Other ways of radiation-sample interaction adapted for liquids or semi-liquids exist, which are practically instantaneous and with limited or null necessity of sample preparation: Transmission and Folded Transmission or Transflectance. The objective of the present work is to compare the precision and accuracy of milk calibration equations in two analysis modes: Reflectance (dry milk) and Folded Transmission (liquid milk). A FOSS-NIR Systems 6500 I spectrophotometer (400-2500 nm) provided with a spinning module was used. Two NIR spectroscopic methods for milk analysis were compared: a) folded transmission: liquid milk samples in a 0.1 pathlength sample cell (ref. IH-0345) and b) reflectance: dried milk samples in glass fibre filters placed in a standard ring cell. A set of 101 milk samples was used to develop the calibration equations, for the two NIR analysis modes, to predict casein, protein, fat and dry matter contents, and 48 milk samples to predict Somatic Cell Count (SCC). The calibrations obtained for protein, fat and dry matter have an excellent quantitative prediction power, since they present $r^2$ values higher than 0.9. The $r^2$ values are slightly lower for casein and SCC (0.88 and 0.89 respectively), but they still are sufficiently high. The accuracy of casein, protein and SCC equations is not affected by the analysis modes, since their ETVC values are very similar in reflectance and folded transmission (0.19% vs 0.21%; 0.16% vs 0.19% and 55.57% vs 53.11% respectively), Lower SECV values were obtained for the prediction of fat and dry matter with the folded transmission equations (0.14% and 0.25% respectively) compared to the results with the reflectance ones (0.43% and 0.34% respectively). In terms of accuracy and speed of analytical response, NIRS analysis of liquid milk is recommended (folded transmission), since the drying procedure takes 24 hours. However, both analysis modes offer satisfactory results.

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