• Journal of Welding and Joining
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• 제2권1호
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• pp.30-40
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• 1984

Moisture content in the coating of an electrode is known to cause defects such as porosities, fish eyes and cracks in the weld metal, however, quantitative relationship between them is not clearly understood. In this study widely consumed and the most common type of arc welding rods such as ilmenite and low hydrogen type were chosen for the investigation, and attempts were made to correlate the relationship between the mechanical properties and gas contents when welding was carried out with electrodes of various moisture contents. As the relative humidity changed from 70% to 92%, it was determined that moisture content to reach saturation was in the range of 0.6~6.8%. As the moisture content in the electrode coating was increased, the amount of gaseous components (H, O, N) in the weld metal was accordingly increased, especially diffusible hydrogen showed prominent effect, i.e. it increased proportionally to the increase of the moisture content. The mechanical properties of the weld metal was observed to become more inferior as the diffusible hydrogen was greater. It was determined for ilmenite type of electrode that the increase of hydrogen content was approximately 1.8ml per unit weight percent increase of moisture and also tensile strength resulted lowering from $45.3kg/\textrm{mm}^2$ to $42.7kg/\textrm{mm}^2$ as moisture content increased from 0.7% to 6.8%. For low hydrogen type the increase of the hyrogen was about 2.4ml per unit percent of moisture and tensile strength decreased from $63.0kg/\textrm{mm}^2$ to $53.8kg/\textrm{mm}^2$ particularly in the region of moisture content 0.1~4.2%.

• Food Science and Biotechnology
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• 제15권6호
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• pp.856-859
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• 2006

The effects of moisture content on non-fracture dynamic properties and fracture gel quality of Pacific whiting surimi were investigated to determine their relationships. Surimi samples were tested at various moisture contents (75, 78, and 81 %). Torsion test showed that shear stress decreased rapidly and strain values decreased gradually as moisture concentration increased. Dynamic storage modulus (G') also decreased as moisture content increased. A strong positive correlation ($R^2=0.90$ to 0.99) was found between the G' measured at temperatures between 10 and $45^{\circ}C$ and fracture stress values. The results indicate that dynamic rheological measurements could be used as a tool for early gel quality assessment.

• Journal of Electrical Engineering and information Science
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• 제2권4호
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• pp.72-78
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• 1997

A free space transmission method using standard gain horn antennas in the frequency range from 9.0 to 10.5GHz is applied to determine the dielectric properties of grain such as rough rice ,brown rice and barley. The dielectric constant and loss factor, which depend on the moisture content of the wetted grain are obtained from the measured attenuation and phase shift by vector network analyzer. The moisture content of grain varied from 11 to 25% based on this wetted condition. The measured values of dielectric constants as a function of moisture density are compared with values of those obtained using he predicted model for estimating dielectric constants of grain. The effect of density fluctuation, high is an important parameter governing the dielectric properties of grain, on the dielectric constant and loss factor is presented. A new density-independent model in terms of measured attenuation an moisture density is proposed of reducing the effects of density fluctuation on the moisture content measurement.

• 한국의류학회지
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• 제24권6호
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• pp.810-818
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• 2000

The purpose of this study was to analyze the effect of geometrical structure on the moisture transport properties of nonwoven batting materials. Two types of nonwovens were used such as single and double layered nonwovens. Steady and dynamic state water vapor transport properties were measured by absorption, evaporation and cobaltous chloride method respectively. The results of this study were as follows: 1) Geometrical structure affected water vapor evaporation, but there were no differences between single and double layered nonwovens in moisture absorption. Thickness and air permeability were influencing factor on water vapor transport rate. 2) Directionality of double layered nonwoven was observed both in steady and dynamic state moisture transport. There were differences between upper and lower layer of double layered nonwoven both in moisture absorption rate and color change by cobaltous chloride method. 3) In dynamic state of water vapor transport rate, single layered nonwoven reached more rapidly at the established relative humidity. It was confirmed that geometrical structure affected water vapor evaporation and hydrophilicity of fiber affected moisture absorption because there were much more water vapor transport rate by evaporation than absorption within the same period of time.

• Journal of Biosystems Engineering
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• 제3권2호
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• pp.62-68
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• 1978

Equilibrium moisture content of rough rice is an important factor because it has a close relationship to storage and drying problems. Determination of the EMC for 10 different varieties of rough rice were made in atmospheres of various constant humidities at three different constant temperatures. In addition , some physical properties were also measured for two different levels of moisture content of the samples. The results may be summarized as follows ; 1. Several physical properties of ten different varieties of rough were measured. Significant difference of the properties was appeared between the varieties in which the difference was pronounced in the dimensions of the varieties. Also, all the dimensions were increased as the moisture content of the rough rice was increased from 14 % to 16%. 2. Significant difference of the equilibrium moisture content was also appeared between some of the varieties in which the equilibrium moisture content of Josaengtongil and Minehikari was 24.26% while that of the others was in the range between 18 to 19% at the conditions of relative humidity of 84% and temperature of 47℃ , respectively. Similar pattern was also observed in other conditions. 3. The values of the constant of Henderson's equation were calculated from the data obtained but they are believed to be useful until more precise and complete data are obtained. There was a good agreement between the calculated and experimental results.

• 자원리싸이클링
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• 제9권3호
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• pp.37-45
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• 2000

본 논문은 가열 페타이어 재활용 아스팔트 혼합물의 습윤과 동결융해 저항성에 대한 시험결과를 나타내고 있다. 재래식 아스팔트 혼합물과 페타이어 재활용 아스팔트의 기계적 특성을 비교하기 위하여 각기 다른 습윤 조건과 동결 융해 횟수하에서 시험이 수행되었다. 또한, 두 혼합물에 대한 최적 아스팔트 함량을 결정하기 위하여 마샬배합설계가 우선 수행되었다. 본 연구에서 수행된 시험결과에 의하면 페타이어 재활용 아스팔트 혼합물의 습윤과 동결-융해 저항성이 재래식 아스팔트 혼합물보다 우수함을 나타내었다. 따라서 향후 도로포장 재료로의 페타이어 재활용은 습윤과 동결융해로 인한 피해를 최소화할 수 있을 것으로 기대된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1155-1158
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• 2003

In this paper, we studied on the electrical characteristics of insulation material of elastomer epoxy. As the results of test, properties of epoxy represent differently according to elastomer contents. Also, its permittivity, tan ${\delta}$ and BDV(Break-Down Voltage) strength show big difference when those compare before moisture absorption test and after moisture absorption test. From this test we find results that mush elastomer contents can cause insulation properties to degrade.

• 한국가구학회지
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• 제19권5호
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• pp.350-357
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• 2008

This research investigates the bending properties to predict the work-energy to maximum load and impact bending energy from static bending and impact bending test. Specimens were prepared from lumber made of thinning crop-trees. Matched specimens were used for MC 12% and green moisture specimens to measure the effect of moisture content on the absorbed energy from static and impact bending tests. The bending properties such as MOE, MOR, etc. is a good predictor to investigate the work-energy and work-energy per unit volume from static bending and impact bending test. The impact bending energy is increased with increasing moisture content. However, the work to maximum load from static bending test is increasing with increasing the MC only for higher density species.

• 한국해양공학회지
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• 제11권4호
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• pp.23-30
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• 1997

The purpose of this paper is to investigate the water environmental effect on the mechanical properties of carbon fiber/epoxy composites. Moisture concentration absorbed in CFRP under various water environment was calculated and degradation of mechanical properties for each wet composite laminates is investigated by performing the flexual and tensile test. The results show that moisture absorption is accelerated in higher temperature environment and under the same temperature sea water environment prompts more absorption than fresh water. As increasing the water temperature and moisture concentration tensile and flexual strength decreased as much as 25%-40% compared with dry condition.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.33-39
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• 2010

The moisture absorption properties such as diffusion coefficient and moisture content ratio of liquid type epoxy resin systems with the filler were investigated. Bisphenol A type and Bisphenol F type epoxy resin, Kayahard MCD as hardener and 2-methylimidazole as catalyst were used in these epoxy resin systems. The nano-sized spherical type fused silica as filler were used in order to study the moisture absorption properties of these liquid type epoxy encapsulant according to the change of filler size. The temperature of glass transition (Tg) of these epoxy resin systems was measured using Dynamic Scanning Calorimeter (DSC), and the moisture absorption properties of these epoxy resin systems according to the change of time were observed at $85^{\circ}C$ and 85% relative humidity condition using a thermo-hygrostat. The diffusion coefficients in these systems were calculated in terms of modified Crank equation based on Ficks' law. An increase of Tg and diffusion coefficient with filler size in these systems can be observed, which are attributed to the increase of free volume with Tg. The change of maximum moisture absorption ratio according to the filler size and filler content cannot be observed; however, the diffusion coefficients of these systems decreased with filler content. The diffusion via free volume is dominant in the epoxy resin systems with low nano-sized filler content; however, the diffusion with the interaction of absorption according the increase of the filler surface area is dominant in the liquid type epoxy encapsulant with high nano-sized filler content.