• Title/Summary/Keyword: thermal variation

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Distance Measurement of Small Moving Object using Infrared Stereo Camera (적외선 스테레오 카메라를 이용한 소형 이동체의 거리 측정)

  • Oh, Jun-Ho;Lee, Sang-Hwa;Lee, Boo-Hwan;Park, Jong-Il
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.3
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    • pp.53-61
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    • 2012
  • This paper proposes a real-time distance measurement system of high temperature and high speed target using infrared stereo camera. We construct an infrared stereo camera system that measure the difference between target and background temperatures for automatic target measurement. First, the proposed method detects target region based on target motion and intensity variation of local region using difference between target and background temperatures. Second, stereo matching by left and right target information is used to estimate disparity about real-time distance of target. In the proposed method using infrared stereo camera system, we compare distances in three dimension trajectory measuring instrument and in infrared stereo camera measurement. In this experiment from three video data, the result shows an average 9.68% distance error rate. The proposed method is suitable for distance and position measurement of varied targets using infrared stereo system.

A High Yield Rate MEMS Gyroscope with a Packaged SiOG Process (SiOG 공정을 이용한 고 신뢰성 MEMS 자이로스코프)

  • Lee Moon Chul;Kang Seok Jin;Jung Kyu Dong;Choa Sung-Hoon;Cho Yang Chul
    • Journal of the Microelectronics and Packaging Society
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    • v.12 no.3 s.36
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    • pp.187-196
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    • 2005
  • MEMS devices such as a vibratory gyroscope often suffer from a lower yield rate due to fabrication errors and the external stress. In the decoupled vibratory gyroscope, the main factor that determines the yield rate is the frequency difference between the sensing and driving modes. The gyroscope, fabricated with SOI (Silicon-On-Insulator) wafer and packaged using the anodic bonding, has a large wafer bowing caused by thermal expansion mismatch as well as non-uniform surfaces of the structures caused by the notching effect. These effects result in large distribution in the frequency difference, and thereby a lower yield rate. To improve the yield rate we propose a packaged SiOG (Silicon On Glass) technology. It uses a silicon wafer and two glass wafers to minimize the wafer bowing and a metallic membrane to avoid the notching. In the packaged SiOG gyroscope, the notching effect is eliminated and the warpage of the wafer is greatly reduced. Consequently the frequency difference is more uniformly distributed and its variation is greatly improved. Therefore we can achieve a more robust vibratory MEMS gyroscope with a higher yield rate.

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Experimental Study on the Dependence of Variation in Performance of a High-Temperature Generator on Its Operating Conditions (운전조건 변화가 고온재생기의 성능에 미치는 영향에 관한 실험적 연구)

  • Bae, Kyungjin;Kwak, Myoungseok;Cho, Honghyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.5
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    • pp.389-397
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    • 2014
  • An absorption chiller-heater using only a natural refrigerant hardly causes any environmental pollution. In an absorption chiller-heater, the performance of its high-temperature generator, which uses exhaust gases, is essential to achieving superior system performance. To investigate the performance of such a high-temperature generator, a laboratory-scale high-temperature generator working with exhaust gases was designed and tested. Changes in the performance of the high-temperature generator as a function of inlet conditions of the absorbing solution, such as air inlet temperature and mass flow, were investigated. It was observed that when the air mass flow rate ratio was increased from 80% to 120%, the heat capacity was increased by 30%, 33%, 34%, and 37%, respectively. Additionally, when the air inlet temperature was elevated from $170^{\circ}C$ to $210^{\circ}C$ for absorption solution concentrations of 56%, 55%, 545, and 53%, the heat capacity increased by 140%, 160%, 220%, and 224%, respectively.

Properties of Light-weight Expanded Bonded Leather Using Thermal Expandable Microspheres (열 팽창성 Microsphere를 적용한 경량 발포 재생피혁 특성 분석)

  • Shin, Eun-Chul;Kim, Won-Ju;Kim, Yeong-Woo
    • Journal of Adhesion and Interface
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    • v.21 no.3
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    • pp.81-85
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    • 2020
  • Shaving dust is a collagen fiber that is the leather waste occurred for thickness adjustment during the natural leather manufacturing process, and causes problems such as an environmental contamination because of a chromium (Cr) contained when it comes to reclaiming process. Various studies applying the shaving dust are currently being conducted in many countries across the world with an initiative by the EU. Of those applications, the bonded leather is being highlighted as a substitute for natural leather. Since the bonded leather, however, uses latex as a binder, accordingly it entails a high weight and a poor ventilation, which are deemed as disadvantages due to its dense internal tissues compared to other synthetic leathers. To address such disadvantages, this study employed the thermally expandable micro sphere to improve its air permeability and light weight by alleviating the internal structure. This is a study on the manufacturing of light bonded leather using the shaving dusts. In the study, the shaving dusts were forced to foam under 100~120℃ considering the heat resistance of collagen fiber after applying the thermally expandable micro sphere, and then the tendency was analyzed. In the analysis results, the most excellent foaming rate was exhibited when the shaving dusts were treated under 120℃ for 8 minutes and the variation of internal structure according to a foaming was observed through SEM analysis for the cross-section of the bonded leather.

Antioxidant, Inhibitory on NO Production and In-vitro Cell Regeneration Effects of Pink-aloe (핑크-알로에의 항산화, NO 생성 억제 및 세포 재생 효과)

  • Lee, Kyung Ju;Jang, Wookju;Kim, You Ah;Park, Byoung Jun;Kang, Hakhee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.46 no.3
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    • pp.273-282
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    • 2020
  • Aloe vera (Aloe barbadensis Miller) has been used since ancient times to improve various skin diseases such as burns, wounds, and eczema. It has been reported that Aloe vera contains vitamin, enzyme, mineral, sugar, phenolic compound, fatty acid and amino acid. Aloe vera changes its color from green to red under the extreme thermal and arid climate to protect itself. These morphological changes induce variation of composition such as increasing of aloe-emodin content. Aloe-emodin is one of the major anthraquinone in aloe family plants. Since aloe-emodin contains a polyphenolic structure, this compound may be responsible for the reported antioxidant and anti-inflammatory effects of aloe. However, there is no research on the process of increasing the compounds of Aloe vera. Therefore, the purpose of this study is to develop a pink aloe manufacturing process that increases the aloe-emodin content and enhances the antioxidant and anti-inflammatory activities of aloe. As a result of heating aloe under appropriate conditions, pink aloe increased aloe-emodin content compared to general aloe, and exhibited effects such as increasing antioxidant activity, inhibiting NO production, and promoting cell regeneration. Through this study, the applicability of pink aloe as a new anti-aging material in the cosmetic field was confirmed.

A Numerical Model to Evaluate Fire-Resistant Capacity of the Reinforced Concrete Members (화재에 손상된 철근콘크리트 부재의 수치모델 및 내화성능해석)

  • Hwang, Jin-Wook;Ha, Sang-Hee;Lee, Yong-Hoon;Kim, Wha-Jung;Kwak, Hyo-Gyoung
    • Journal of the Korea Concrete Institute
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    • v.25 no.5
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    • pp.497-508
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    • 2013
  • This paper introduces a numerical model which can evaluate the fire-resistant capacity of reinforced concrete members. On the basis of the transient heat transfer considering the heat conduction, convection and radiation, time-dependent temperature distribution across a section is determined. A layered fiber section method is adopted to consider non-linear material properties depending on the temperature and varying with the position of a fiber. Furthermore, effects of non-mechanical strains of each fiber like thermal expansion, transient strain and creep strain are reflected on the non-linear structural analysis to take into account the extreme temperature variation induced by the fire. Analysis results by the numerical model are compared with experimental data from the standard fire tests to validate an exactness of the introduced numerical model. Also, time-dependent changes in the resisting capacities of reinforced concrete members exposed to fire are investigated through the analyses and, the resisting capacities evaluated are compared with those determined by the design code.

Feeding of Juvenile Purple Washington Clam, Saxidomus purpuratus (Sowerby): Effects of Algal Concentration and Temperature

  • Lee, Chang-Hoon;Choi, Yong-Suk;Bang, Jong-Deuk;Jo, Soo-Gun
    • Journal of Aquaculture
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    • v.15 no.4
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    • pp.253-260
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    • 2002
  • To find the optimal rearing conditions for Saxidomus purpuratus juvenile, filtering activity was estimated as functions of algal concentration and temperature by measuring the rates of clearance (CR) and ingestion (IR), when S. purpuratus was feeding. The clams were fed on unialgal diet of Isochrysis galbana at 6 algal concentrations (4.6$\times$$10^4$~2.6$\times$$10^6$ cells/ml) and at 6 temperatures (5, 10, 15, 20, 25, and 30^{\circ}C ). Algal concentration significantly affected the CR and the IR at all temperatures. At lower algal concentrations, CR increased, but decreased beyond a particular concentration. The maximum CR ($CR_{max}$) at 5, 10, 15, 20, 25, and 30^{\circ}C were 0.30, 1.73, 5.95, 15.17, 21.12, and 0.33 $l/g/h$, respectively. Below the level of 5.6$\times$10$^{5}$ cells/ml, IR increased as algal concentration increased, but was saturated at higher concentrations. To maintain high growth rate of S. purpuratus, I. galbana should be supplied with more than 5.6$\times$10$^{5}$ cells/ml. The maximum IR ($IR_{max}$) at 5, 10, 15, 20, 25 and30^{\circ}C were $2.2$\times$10^8, $1.5\times$10^9, 3.4$\times$10^9, 4.9$\times$10^9, 5.3$\times$10^9, and 1.0$\times$10^8$ cells/g/h, respectively. As for temperature, both $CR_max$ and $IR_max$ increased remarkably with raising temperature from 5 to 25^{\circ}C, but rapidly decreased at 30^{\circ}C. Between 15 and 25^{\circ}C $CR_{max} and IR_{max}$ were higher and most stable, At this temperature range, the $Q_{10}/s for CR_{max} and IR_{max}$ were 3.5 and 1.6, respectively. Therefore the optimal thermal range for the juvenile is 15~$25^{\circ}C$. The annual variation in IR$_{max}$ predicted by natural seawater temperature shows that inactive period (with lower $IR_max$) lasts for 5 months (from December to April). To ensure higher growth of juvenile during this inactive period at hatcheries, rearing temperature should be elevated to $15^{\circ}C$.>.

Seasonal variation in growth of Berkshire pigs in alternative production systems

  • Park, Hyeon-Suk;Oh, Sang-Hyon
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.5
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    • pp.749-754
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    • 2017
  • Objective: The objective of the present study was to investigate the effects of farrowing month (FM), parity and sex on the growth performance of Berkshire swine raised in alternative production systems. Methods: A total of 40 farrowing records from 27 sows and 1,258 body weight (BW) records from 274 piglets collected over a two-year period were used for the analysis. The BWs were recorded at birth, weaning (28 d), 56, 84, 112, and 140 days. Any BW not recorded on schedule was recalculated to conform the days of age among corresponding BW records, using growth curves drawn with polynomial functions whose power was determined by the number of existing observations for each individual. Results: The mean parity (${\pm}$standard deviation) of the sows was $3.42{\pm}2.14$. The sows that farrowed in June had the lowest number of total born with an average of $6.25{\pm}2.22$ piglets per sow. However, the lowest average number of piglets weaned at day 28 was found in sows that farrowed in May, as well as the highest number recorded for the stillborn piglets with an average of 2.67 piglets per sow. Moreover, the smallest increase in weight from birth to weaning occurred in piglets that were farrowed in May, which also corresponds with the average daily gain (ADG) of 0.29 kg and the last recorded weight measurement on day 140 of $41.69{\pm}1.45kg$. Contrastingly, the highest growth rate was found among pigs farrowed in June, with the largest increase in weight of 7.55 kg from birth to weaning, the highest ADG of 0.51 kg from birth to 140 day of age and the highest BW of $74.70{\pm}1.86kg$ recorded on day 140. Conclusion: Pigs farrowed in June also had the least number of piglets that died between birth and weaning. The zone of thermal comfort found in sows reared in indoor confinement systems did not improve the reproductive performance of the sows reared in an outdoor, alternative production system, while the growth performance of the piglets was improved when the ambient temperature was consistently hot or consistently cold.

Process Development for Production of Ultramarine Blue from Kaolin (고령토로부터 군청안료 제조)

  • Choi, Young-Yoon;Lee, Hoo-In;Kim, Byung-Su;Kim, Sang-Bae
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.2
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    • pp.107-114
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    • 2009
  • In present study, an alternative process for manufacturing ultra marine blue by using kaolin, sulfur, sodium carbonate, silica, and rosin was investigated. From the experiments, it was found in the reductive calcination process that the temperature variation with the bed height of input materials is relatively high due to the inadequate thermal conductivity of them. It was also found that the color of the ultramarine blue manufactured is sensitive for the shape of the input materials and the calcinations conditions, and specially the heating rate is very important to form ultramarine. For manufacturing green ultramarine by using sulfur, sodium carbonate, silicon, and pine resin, an optimum condition was investigated to be the heating rate region below $0.6^{\circ}C/min$, the reaction temperature of $850^{\circ}C$ and the reaction time of 4 hr. At the oxidative calcination process to manufacture ultra marine blue from green ultramarine, the optimum flow rate of air is $500{\sim}550\;{\ell}/kg$ (green ultramarine) and the reaction temperature is $500{\sim}550^{\circ}C$.

Dynamic Changes of Dissolved Oxygen during Summer Monsoon (하절기 장마동안 용존산소의 역동적 변화)

  • An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.33 no.3 s.91
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    • pp.213-221
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    • 2000
  • Seasonal oxygen content and deficit rates were evaluated from 17 sites of Taechung Reservoir during 1993${\sim}$1994. In 1993, river inflows peaked during the monsoon in July${\sim}$August and disrupted thermal stratification and anoxic layers in the headwaters, thereby confining the anoxia to the mid-lake and downlake reach. The volume of anoxic water with < 4 mg/l DO comprised only < 10% of the total lake volume in this period. In contrast, during monsoon 1994, 85% of total lake volume was subject to hypoxic conditions with oxygen concentrations < 30% saturation, resulting in massive fishkills (Hypomesus olidus). Relative areal oxygen deficit (RAOD) was -0.024mg O$_{2}$cm$^{-2}$d$^{-1}$ during monsoon 1993, whereas it rapidly decreased at the rate of 0.080mg O$_{2}$cm$^{-2}$d$^{-1}$ during monsoon 1994. Anoxic factor (AF) showed a same interannual pattern as the RAOD and was greater >50 d in 1994 (76.5 d) than 1993 (21.3 d). Thus, the reservoir showed a river-characteristics (6${\sim}$11 mg/l DO) in 1993 while lacustrine conditions (<4mg/l DO) dominated in 1994. Regression analysis showed that the variation of summer DO was mostly determined (R$^{2}$=0.99, p<0.0001) by inflow. These findings suggest that the primary factor regulating the oxygen content in this system during summer is an intensity of the monsoon rain.

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