• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.703-709
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• 2018

Dielectric heating materials were prepared through the thermal treatment for composites of Li and Zn type precursors that are major materials being responded to microwave under diversified conditions. The prepared heating material samples were analyzed by SEM and it was confirmed that $Li_5Fe_5O_8$ materials being formed on the surface was a major influencing factor for the heating performance. Heating materials improved the moisture removal in a sludge drying facility, for example, the moisture content of 25 v/v% sludge decreased to 15.22 v/v%. Accordingly, heating materials were confirmed to directly affect the performance and efficiency of the microwave drying process.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.28-32
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• 1993

In order to elucidate the temperature and pressure effect on the oil expression of perilla seed, recovery of expressed oil (REO) and volumetric strain of both roasted and unroasted perilla seeds were observed at different temperature, pressure and for different periods of press. In this experiment, moisture content of perilla seed was adjusted to 2.5% and temperature used were 30, 40, 50 and $60^{\circ}C$. Pressure applied were 10, 30, 50 and 70 MPa, and periods of press were 5, 7, 9 and 11 min. As temperature and pressure were increased or periods of press was lengthened, REO and volumetric strain of pressed cake were increased. Maximum REO of unroasted perilla seeds were found to be 85.59% and those of roasted perilla seeds be 85.30%, at 70 MPa, $60^{\circ}C$, and for 11 min. Viscosity of expressed oil were exponentially dependent on temperature and REO were increased as viscosity was decreased. From statistical analysis between effects of expression factors and REO and volumetric strain of pressed cake, importance of their effects was decreased in the order of pressure, temperature, $temperature{\times}pressure$ and periods of press. The multiple regression equation between REO(Y) and temperature (T), pressure (P), and periods of press (D) were as follows; $Y=7.95+36.85P+1.12T^2-0.55TP-5.08P^2\;r^2=0.97$ for unroasted perilla seed (p<0.01), $Y=4.50T+39.23P+0.83T^2-1.71P-5.07P^2\;r^2=0.99$ for roasted perilla seed (p<0.01).

• Food Science and Preservation
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• v.16 no.1
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• pp.23-32
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• 2009

This study evaluated quality characteristics of spirulina (0.63, 1.25, and 2.5%, all w/w) added noodles during storage at 4C. Total bacterial counts in raw spirulina added noodles were higher than those of the control during storage, but no bacteria were detected in cooked noodles. Escherichia coli was not detected in any group. The weight loss, volume loss, and moisture absorption of spirulina added noodles were somewhat greater than control values. Moisture contents of spirulina added noodles both before and after cooking decreased as the spirulina level increased. During storage, moisture loss from spirulina added noodles was a little greater than from the control. Hunter color values for L (lightness), a (redness), and b (yellowness) decreased during storage. The spirulina added noodles had significantly greater hardness, cohesiveness, gumminess, and chewiness compared with the control. The antioxidant activity of spirulina added noodles increased with spirulina level. A sensory preference test revealed that noodles with 1.25% spirulina received the highest scores for chewiness, overall preference, and buying intention. It is suggested that spirulina could be added to noodles at a concentration of up to 1.25% to improve quality.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.87-91
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• 2015

There is no specific data on Entomogenous fungus (DongChungHaCho) in accordance with the silkworm varieties, despite of very high value industrial use as functional materials at domestic and abroad. In this study, we investigated culture condition and characteristics of Paecilomyces tenuipes in 3 silkworm cultivars and 2 specific silkworm breeds. Infection rate of P. tenuipes for silkworm varieties was the highest Kumokjam, followed by Baegokjam, Daeseongjam, Golden silk, Yeonnokjam in that order. The optimum culture conditions were as follows: dark condition, $22^{\circ}C{\pm}1$, and about $4cm^2$ in planting density per pupa. Also, we have developed annual production technologies of P. tenuipes. First, in order that the moisture content of the infection pupa became 3% or less in the natural condition. Second, the dried pupa must be vacuum-packed and was kept under $4^{\circ}C$. Finally, by restoring the moisture content of the dried pupa and culture in optimal condition, the technique for annual production of the P. tenuipes was achieved. Therefore, we expect that the use of Kumokjam and annual production technique will contribute significantly to farm income.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.201-216
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• 2013

Ground penetrating radar (GPR) surveys were conducted in a sand tank model in a laboratory and at an alluvial field site to detect the groundwater table and to investigate the influence of saturation on GPR response in the unsaturated zone. In the sand tank model, the groundwater table and saturation in the sand layer were altered by injecting water, which was then drained by a valve inserted into the bottom of the tank. GPR vertical reflection profile (VRP) data were obtained in the sand tank model for rising and lowering of the groundwater table to estimate the groundwater table and saturation. Results of the lab-scale model provide information on the sensitivity of GPR signals to changes in the water content and in the groundwater table. GPR wave velocities in the vadose zone are controlled mainly by variations in water content (increased travel time is interpreted as an increase in saturation). At the field site, VRP data were collected to a depth of 220 m to estimate the groundwater table at an alluvial site near the Nakdong river at Iryong-ri, Haman-gun, South Korea. Results of the field survey indicate that under saturated conditions, the first reflector of the GPR is indicative of the capillary fringe and not the actual groundwater table. To measure the groundwater table more accurately, we performed a GPR survey using the common mid-point (CMP) method in the vicinity of well-3, and sunk a well to check the groundwater table. The resultant CMP data revealed reflective events from the capillary fringe and groundwater table showing hyperbolic patterns. The normal moveout correction was applied to evaluate the velocity of the GPR, which improved the accuracy of saturation and groundwater table information at depth. The GPR results show that the saturation information, including the groundwater table, is useful in assessing the hydrogeologic properties of the vadose zone in the field.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.122-134
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• 2015

This study was conducted to investigate the potential of torrefied larch wood as a raw material of pellets. First of all, larch chip was torrefied at the temperatures of 230, 250 and $270^{\circ}C$ for 30, 50 and 70 min. Secondly, moisture content, moisture absorption, higher heating value and ash content of the torrefied chip were measured to examine the effects of torrefaction conditions on the fuel characteristics of larch. Thirdly, surfaces of the torrefied chip were observed by light microscope (LM), field emission scanning microscope (FE-SEM) and SEM-energy dispersive spectroscopy (EDXS). With the increases of torrefied temperature and time, contents of lignin increased and those of hemicellulose reduced. Moisture content of torrefied larch chip was greatly lower than that of non-torrefied chip. Moisture absorption of the torrefied chip decreased as torrefaction temperature increased. As torrefaction temperature increased, higher heating value and ash content of larch chip increased. However, durability of torrefied-larch pellets was remarkably lower comparing to non-torrefied-larch pellets. When surface of larch chip was observed by LM and FE-SEM, surface color and cell wall of the chip was getting darker and more collapsed with the increases of torrefaction conditions. Through the analysis of SEM-EDXS, distribution and quantity of lignin existing on the surface of larch chip increased with the increases of torrefied conditions. In conclusion, $270^{\circ}C$/50 min might be an optimal condition for the torrefaction of larch with the aspect of fuel characteristics, but torrefaction condition of $230^{\circ}C$/30 min should be considered according to the durability of torrefied-larch pellets.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.1
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• pp.128-132
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• 1983

The water relations parameters such as original osmotic pressure $(\Pi_0)$, osmotic pressure $(\Pi_p)$, at the incipient plasmolysis, the volume of osmotic water $(V_o)$ at the full turgor, the relative water content $(RWC^*)$ at the incipient plasmolysis, the volume of osmotic water$(V_p)$ at the incipient plasmolysis, the volume of symplasmic and apoplastic water$(w_s)$ at the maximum turgor, $V_pV_o, \; V_oW_s, \; W_sD_w, \; V_oF_w$ and the elastic modulus were measured through the pressure chamber (DIK-PC-40 Model) technique with the Williams and Geumgangdaerip soybean cultivar shoots. The original osmotic pressure$(\P $i_{0}$ )$, of the both cultivars shoots were appeared insignificant differences as 8.1 bar and 7.8 bar respectively. The osmotic pressure($\pi$$_{p}$ ) at the incipient plasmolysis was 9.0 bar in Williams and 10.4 bar in Geumgangdaerip. The relative water content(RW $C^{*}$) at the incipient plasmolysis was 86.0 per cent in Geumgangdaerip and 92.6 per cent in Williams. The ratio of volume of osmotic water( $V_{p}$ ) at the incipient plasmolysis to total symplasmic water$(V_o)$ , i.e., $V_p/V_o$ was 83.4 per cent in Geumgangdaerip and 90.4 per cent in Williams. The elastic modulus of Geumgangdaerip shoots showed higher value than Williams$(8.5 $\times$ 10^2bar)$ as $1.6 \times10^5$ bar.r.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.29-37
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• 2008

The objective of this research is to evaluate the optimum treatment methods for disposal sludge cake at different temperatures and periods of time. The disposal dehydrated sewage cake used in this study was obtained from N wastewater treatment plant in the P City. This system consists of continuous conveyer thermal dryer and pyrolysis. The continual conveyer thermal dryer was operated to evaluate the optimum conditions with temperature settings, ranges from 130 to $180^{\circ}C$, loading rates of 650~750 kg/hr and operating times of 110~120 minutes. The continual pyrolysis was also operated to evaluate the optimum conditions with temperature settings, ranges from 650 to $750^{\circ}C$, loading rates of 100~158 kg/hr and operating times of 20~40 minutes. The sewage sludge cake has a moisture content of 78~80% (wt) which decreased up to 1~3%(wt) resulted in breaking of cell wall after operating the continuous conveyer thermal dryer and pyrolysis. Important parameters which were operating times, moisture contents, loading rates, conveyer velocities and rotary velocities effects on the thermal kinetics and dynamics were investigated to evaluate the optimum conditions for the continual thermal dryer and pyrolysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.11a
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• pp.35-36
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• 1997

복합재는 강도가 높고 가볍기 때문에 최근 로켓의 연소관으로 널리 사용되고 있다. 그런데 이 복합재 로켓 연소관은 제조 후 대기 환경에 장기적으로 노출되어 있기 때문에 금속 연소관과는 달리 온도 또는 습도 등의 환경에 대한 영향을 고려해야 한다. 더구나 연소관은 내부에 추진제가 충전되어 있으므로 추진제의 기계적 특성이 습도에 민감함을 생각할 때 강도뿐만 아니라 습기의 투과도 또한 매우 중요한 고려 요소가 된다. 그러나 온/습도 변화에 따른 복합재 자체의 재료 특성 변화에 대한 연구는 많이 보고되었으나 습기의 투과 정도에 관한 연구는 자료가 미흡한 실정이다. 한편, 포화 함수율은 복합재에 따라서 차이가 있으나 T300/5208의 경우 문헌을 참조하면 20-$50^{\circ}C$에서 복합재 무게의 약 1.5% 정도이며 포화에 걸리는 시간은 약 100일 정도로 나타나 있다.본 연구에서는 수분이 복합재를 통하여 투과되는 정도를 고찰하기 위하여 $20^{\circ}C$,95%RH의 온/습도를 유지하는 수조를 제작하였고, 이 수조내에 보관한 복합재 연소관의 실린더 벽면으로 투과되는 습기를 측정하기 위하여 연소관 내에 습도 센서를 투입하여 상대습도를 직접 측정하였다. 복합재 연소관이 로켓에 사용될 때는 연소관 외부에 페인트로 피막 처리하고 연소관 내부에도 추진제와의 사이에 라이너가 접착되어 있어서 수분 침투 및 온도 등의 외부 환경조건에 견디기에 더 양호한 조건이나 본 연구에서는 복합재 자체의 특성을 고찰하기 위하여 섬유를 에폭시에 함침시켜 winding한 상태 그대로의 복합재 연소관 시료를 사용하였다. 습기의 투과는 내부에 라이너/인슐레이션이 피복되거나 또는 추진제가 충전된 경우 많은 감소효과를 보였다. 순수 복합재 연소관의 경우 수조에 넣고 평형에 도달한 후로부터 약 8개월의 습기 투과 상태를 볼대 벽면을 통하여 들어가는 water vapor flux는 $20^{\circ}C$,95%RH 에서 평균적으로 9.3163$\times$$10^{-8}$g/$m^2$sec로 나타났다. 이때 습기가 투과되는 연소관이 국지점을 평판으로 가정하고 Fick's law를 이용하여 구한 습기에 대한 복합재의 확산계수는 D=2.5$\times$$10^{-6}$$mm^2$sec였으며, 이는 다른 graphite/epixy 복합재의 확산계수와 유사한 값을 나타내고 있다. 또한 추진제가 충전된 연소관을 절단하여 밀폐한 후 95%RH 습도 조건에 보관함으로써 연소관 내부의 추진제 기계적 특성에 미치는 침투된 습기의 영향도 함께 고찰하였다. 추진제에 따라 차이는 있겠으나 추진제가 충전된 연소관은 순수 복합재 연소관에 비해 습기의 투과 정도가 작으며, 본 연소관에 충전된 RDX/AP계 추진제의 경우 추진제의 습기투과에 의한 추진제 물성 변화는 미미한 것으로 나타났다.

• Membrane Journal
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• v.21 no.4
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• pp.389-397
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• 2011

In this study, polymer composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) were prepared using a solution casting method with different amount of vermiculite (VMT) content. The dispersion of VMT particles in the SPAES matrix was confirmed by means of a scanning electron microscopy observation. The composite membrane containing less than 1 wt% of VMT has a smooth skin on the top and bottom, which means there is a good dispersion of VMT in the matrix. The water uptake of the composite membranes gradually increases as the temperature increases, and the results confirm that all the adsorbed water is bound water because VMT has a strong water affinity on account of its high cation exchange value. A composite membrane with a VMT content of less than 1 wt% increases the proton conductivity and reduces the methanol permeability. Of all the composite membranes, the membrane SPAES/VMT 1.0 has the best fuel cell performance in terms of membrane selectivity. The performance value of SPAES/VMT 1.0 is double that of Nafion 112, which suggests that SPAES/VMT1.0 could be an excellent candidate for direct methanol fuel cells.