• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2364-2369
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• 2015

In this paper, the optimum RPM was suggested comparing rotor filling rate of RPM through the analysis of rotor's filling rate as studying and developing centrifugal-casting machine's method for high precision rotor in order to increase the related types of business's productivity. The result was similar to other result in industrial site, showing 99.47% of filling rate when rotational speeds are 600 rpm, so it is considered that if this result is conducted with additional research, it will be possible to plan a better process design. Besides, the optimum temperature of compact ladle was examined to produce high quality casting product through the analysis of compact ladle's conductivity. In the case of the heating device's absence using nicrome wire, Al solution solidifies falling drastically into $427^{\circ}C$. However, it is feasible to work over $427^{\circ}C$ which is the melting temperature of aluminium solution when the heating device of nicrome wire is included. It reveals that there is little temperature change.

• Journal of the Korean Magnetics Society
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• v.24 no.2
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• pp.56-59
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• 2014

The samples of $Ba_2CoZnFe_{12}O_{22}$ was synthesized by the solid-state reaction method. The toroids of $Ba_2CoZnFe_{12}O_{22}$ were sintered with various sintering temperature at 1050, 1100, 1150, and $1200^{\circ}C$, and studied by x-ray diffractometer, vibrating sample magnetometer, network analyzer, and Mssbauer spectrometer. From the XRD patterns, the density of samples increased with increasing sintering temperature. From the magnetic hysteresis curves up to 10 kOe at 295 K, the saturation magnetization ($M_s$) of $Ba_2CoZnFe_{12}O_{22}$ samples in various sintered at 1050, 1100, 1150 ,and $1200^{\circ}C$ were showed around $M_s$= 33.0 emu/g. However, With increasing sintering temperature, the coercivity ($H_c$) of samples decrease. Complex permeability and permittivity of samples in various sintering temperatures were measured between 100MHz to 4 GHz. With increasing sintering temperature, the permeability of samples increase.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.25-32
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• 2006

Behavior of concrete pavement due to temperature gradient was investigated for 48 hours at test road using Falling Weight Deflectometer. The deflections at slab center changed similarly to those of ambient temperature and temperature gradients in the slab. And rapid variations in the deflections were observed between 8 to 12 in the morning. However, dynamic modulus of subgrade reaction and joint deflections showed reverse trends to the ambient temperature and temperature gradients. The dynamic modulus of subgrade reaction was significantly affected by temperature gradient when its value got higher. Backcalculated elastic moduli were obtained using AREA method and Method of Equivalent Thickness. The trends of the backcalculated elastic modulus were similar to those of dynamic modulus of subgrade reaction. Measured load transfer efficiencies showed maximum peak in the morning due to dowel locking. However, additional effort is necessary to verify the result.

• Electrical & Electronic Materials
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• v.3 no.1
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• pp.20-28
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• 1990

Pb(Zr, Ti)O$_{3}$-Pb(Ni, Nb)O$_{3}$계 세라믹스에 Ba를 치완시켜 Ba치환량의 증가에 따른 유전율, 전기기계결합계수 및 압전 d정수의 변화를 고찰하였다. 또한 Ba치환에 따른 세라믹스 소자의 송신감도 특성을 조사하고 큐리온도 이동에 따른 온도안정성을 고려하여 초음파 송신기용 압전소자에 응용가능함을 보였다.

• 전기의세계
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• v.28 no.2
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• pp.3-13
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• 1979

전동기는 산업설비의 동력원으로 널리 사용되고 있으며, 그 운전의 신뢰성은 설비의 가동율에 큰 영향을 미친다. 따라서 전동기의 운전신뢰성을 높이려면 예상 할 수 있는 고장원인에 대하여 여러가지 보호대책이 필요하다. 전동기의 고장원인중 권선의 소손, 열화는 전체고장원인의 50~60%를 점하고 있어 이에 대한 보호에 각별한 배려가 있어야 한다. 전동기의 소손보호는 권선온도가 소손사고에 이르기 전에 회로로부터 전동기를 회로로부터 분리하는데 있으며, 권선온도를 직접 검출하는 보호방법이 이상적인 방법이라 할 수 있다. 그러나 경제성, 취급성 등의 면에서 소손원인에 기인하는 전기적현상의 변화(주로 전류)를 감시하여 간접적으로 보호하는 방식도 많이 사용되고 있다. 여기서는 저압삼상유도전동기를 위주로 하여 고장의 원인과 그 보호장치및 보호방식에 관해서 기술코저한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.4
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• pp.892-898
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• 1990

본 연구에서는 소형 연소로에서 단입자 석탄화염을 형성하고 스펙트럼 분석기 를 통하여 순간적으로 입자 발광스펙트럼을 획득하고 이를 컴퓨터에서 분석하는 장치 를 구성하였다. 입자로부터의 발광신호(luminous signature)를 측정하여 연소과정에 서의 복사거동을 파악하여 이로부터 광학적 온도측정을 하는 방법을 보고하다. 본 논문에서는 미분탄 입자 화염의 in-situ측정에 의한 스펙트로스코피 방법을 보고하는 데에 중점이 있으므로 전형적인 화염의 스펙트럼에 의한 자료분석 방법을 제시하였고 화염조건에 따른 결과치의 변화상황은 별도로 보고한다.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.267-267
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• 2017

• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.40-44
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• 1978

Cerium (IV) ion-initiated graft copolymerizations of acrylonitrile to raw silk were investigated in an effort to carry out sericine-fixation. The change in ceric ammonium nitrate concentration exhibited a maximum in percentage of grafting at 0.003M. Also observed was that the change in nitric acid content in reaction media gave a maximum in percentage of grafting at 0.1M. Percentage of grafting was increased generally with increase in acrylonitrile concentration, reaction time and reaction temperature. Raw silk sericin grafted with acrylonitrile was not de gummed by boiling off test and optimum graft percentage was considered at 20%.

• Journal of Animal Environmental Science
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• v.11 no.1
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• pp.1-10
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• 2005

This study was carried out to measure the environmental related parameters from two types of swine houses. Indoor temperature, relative humidity, carbon dioxide level, ammonia concentration and emission were measures every 2 minutes from each house with portable monitoring units. Carbon dioxide concentration balance was used to estimate the ventilation rates of the different houses. Daily ammonia concentrations in the growing-finishing and farrowing houses ranged from 2 to 17 ppm and 6 to 15 ppm respectively. The daily ammonia emission rate from the manure averaged 4.37 g/h$\cdot$500 kg from growing-finishing house and 4.82 g/h$\cdot$500 kg from the farrowing house. The above findings proved that summer season was associated with higher ammonia emission rates due to higher ventilation rate and ambient air temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.1
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• pp.29-36
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• 2021

In spite of the highest energy potential among all domestic organic solid wastes. the research on biogas production from cattle manure is limited. In particular, effects of organic content degradation and sawdust addition during storage on biomethane potential have never been investigated. In the present work, we investigated the change of organic content during storage of cattle manure under different temperatures (20℃ and 30℃), and its impact on biomethane potential and odor emissions. 90 days of investigation results showed that 10% of organics in terms of VS and COD were degraded at 20℃ during storage, while 30% were degraded at 30℃. This result impacted on biomethane potential, while 10-13% and 24% reduction were observed from beef and dairy cattle manure, respectively. The temperature also affected on CH4 and odor emissions during storage by 3.3-3.8 times and 29 times. The effect of sawdust on lowering down biomethane potential was found to be substantial, reducing 61-75% compared to the control.