Earticle

In this study, spray-drying yield and morphological characterization of spray-dried cellulose nanofibril (CNF) and TEMPO-oxidized nanocellulose (TONC) depending on spray-drying condition and surfactant addition was investigated. As spray-drying temperature increased, the yield of spray-dried CNF was increased. The highest spray-drying yields in both nanocelluloses were found at didecyl dimethyl ammonium chloride (DDAC) addition of 2.5 phr at all investigated temperatures. The spray-dried CNF was the sphere-like particle, but the spray- dried TONC showed both rod and sphere-like morphology. The average diameter of spray-dried CNF was decreased with increasing DDAC addition amount, resulting in the increase of specific surface area.

Recently, various efforts to make more speedy and precision machine tool to improve productivity and also various efforts to solve environmental problem are going on, so that dry cutting in manufacturing industry, which needs environmental conscious design and development of manufacturing technique, is becoming a very important assignment to solve. Because dry cutting does not use cutting fluid, we need other methods that can be used instead of cutting fluid, which does cooling, lubricating, chip washing, and anti-corrosion. Especially, because turning is a continuous work, the consideration of tool life and surface roughness due to continuous heat and poor lubrication is important. The purposes of this paper are the consideration of how well the compressed air can work instead of cutting fluid, and also the development of the method to select the optimum machining condition by the minimum numbers of experiments through the Taguchi method.

돼지고기 저지방 부위의 활용도를 제고하기 위해 54개의 뒷다리를 사용하여 소금 처리수준과 건조기간이 건염햄의 중량감소 및 영양적 특성에 어떠한 영향을 미치는지를 조사하기 위해 소금 처리수준을 고염구(7%), 중염구(5%), 저염구(3%)로 하여 180일, 270일, 360일 동안 건조하여 건염햄을 제조하였다. 제조단계별 소금처리량에 따른 중량감소율을 조사한 결과, 염지단계에서는 고염구의 중량감소율이 5.62%로 가장 높았고, 염지 후 정치단계에서는 저염구의 중량감소율이 12.35%로 가장 높았으며, 발효단계에서는 고염구가 저염구보다 유의적으로 높은 중량감소율을 보였다(p<0.05). 또한 건조단계에서는 모든 소금 처리수준에서 건조기간이 증가할수록 중량감소율이 증가하는 경향을 보였다(p<0.05). 원료육 대비 총 중량감소는 염지 시 사용된 소금처리 수준에는 영향을 받지 않으며, 건조기간이 길수록 감량이 많아졌다. 건조기간은 단계별 소금처리수준 모두에서 수분함량을 감소시켰으며(p<0.05), 상대적으로 조지방과 조단백질 함량이 증가하는 경향을 보였다. 또한 건조 기간은 건염햄의 지방산 조성에도 영향을 미쳤으며, 건조기간이 길어질수록 포화지방산 함량은 많아지고 불포화지방산 함량은 줄어드는 경향을 보였다.

The aim of this study was to offer information about appropriate processing method for dry cured-ham with controlled ripening condition. In this study, three different treatments were performed: High salt group(HS), 18 hams were salted with 70g kg－1 salt (w/w) Middle salt group(MS), 18 hams were salted with 50 g kg－1 salt Low salt group(LS), 18 hams were salted with 30g kg－1 salt. Also three drying periods were applied(180 days, 270 days and 360 days). The weight loss in HS was higher(5.62%) on curing step and in LS was higher(12.35%) on post-salting step compared to other groups. On fermentation stage, weight loss of HS was higher than that of LS(p<0.05). Weight loss on drying was increased as the drying period passes(p<0.05). Moisture contents were significantly(p<0.05) decreased and fat contents were significantly(p<0.05) increased in all treatment groups as drying period increased. The different drying periods affected fatty acid compositions on all salting levels; saturated fatty acid contents were increased(p<0.05) with more drying, whereas unsaturated fatty acid contents were decreased(p<0.05) as drying period increased.

This study was performed to evaluate the effect of drying methods on the polyphenol contents and antioxidant activities of Hizikia fusiformis. The seaweed was dried using four different conditions: vacuum drying (VD) at $20^{\circ}C$ and $30^{\circ}C$ and hot-air drying (HD) at $40^{\circ}C$ and $60^{\circ}C$. After drying, the total phenol content, DPPH and nitrite scavenging activities of the water extracts were determined. The total phenol contents were significantly (p<0.05) higher in the vacuum dried samples than the hot-air dried samples. DPPH radical was scavenged 82.67% and 83.45% by VD-20 and VD-30, and 70.44% and 71.23% by HD-40 and HD-60, respectively. At pH 1.2, Hizikia fusiformis scavenged 87.43%, 88.45%, 72.14% and 73.45% of nitrite by the treatment VD-20, VD-30, HD-40 and HD-60, respectively. Interestingly, the nitrite scavenging activity was much more reduced at pH 3.0 than at pH 1.2. Through these experiments, we were able to show that the drying conditions affect the total phenol contents and antioxidant capacities of Hizikia fusiformis.

The purpose of this study was to investigate the influence of processing conditions (temperature and time) and binding agent types (glutinous rice flour, potato starch, bean flour, and acorn flour) on the physicochemical and sensory characteristics of ground dried-pork meat product. For this purpose, ground dried-pork meat product was produced by adding several binding agents at different drying temperatures and times. The drying time affected moisture content and water activity in all drying temperature. However, under the similar drying conditions, the extent of drying varied depending on the type of binding agents. The results of sensory evaluation for texture degree and overall acceptability indicated the following: overall, higher drying temperatures and longer drying time heightened the degree of texture, and the overall acceptability varied depending on binding agent type. Physicochemical and sensory characteristics were analyzed to determine any possible correlation. The results revealed a high correlation between moisture content, water activity, shear forces, and sensory evaluation (p<0.01). However, there was no correlation with respect to overall acceptability.

This paper suggests the optimal conditions to prevent electrostatic charge in the laundry by the evaluation of the electrostatic characteristics during the drying process. Cotton, nylon, and polyester fabrics were used as test specimens, employing the standard washing cycle. The electrostatic characteristics of the laundry were measured after the automatic drying process. This paper investigates the optimal conditions for preventing electrostatic charges in laundry by evaluating the electrostatic characteristics that occur during the drying process. Cotton, nylon, and polyester fabrics were used as the test specimens, employing a standard washing cycle. The electrostatic characteristics of the laundry were measured immediately after the automatic drying process. The results, showed that the moisture content decreased and the electrostatic charge increased with drying time. The specimen fabrics had already dried up before completion of the standard drying cycle. Consequently, the excessive drying generated an electrostatic charge due to removal of the traces of remaining moisture and the resulting excessive friction. For cotton fabrics, the electrostatic charge was under 1000 V even for the maximum drying time due to the intrinsic high moisture regain of cotton. On the other hand, the electrostatic charge produced for nylon fabrics increased rapidly with the drying time, and amounted up to approximately 8000V after 120 minutes. The results also indicated that the electrostatic charge could be decreased by drying fabrics of only one kind. When mixed kinds of fabrics were dried, the electrostatic charge increased remarkably. Therefore, it is suggested that laundry be classified and washed according to the kinds of fiber, and not be dried excessively to reduce electrostatic charge. In addition, the proper use of a softener is effective in reducing the electrostatic charge.

Using the relatively low-cost, far-infrared dryer inhibiting the destruction of a variety of physiologically active components of the mulberry fruit, we have studied to make semidry mulberry fruit that can be kept at room temperature for a long time. By adjusting the temperature of the far-infrared dryer step-by-step, we developed a semi-dry method of maintaining the shape of the mulberry fruit. In addition, by drying the coating of honey after removing the juice generated by the mulberry fruit thawing process improved the acceptability of the taste of fruit. We conducted heat treatment mulberry fruit into a $95^{\circ}C$ infrared dryer 5 hours to thaw the frozen mulberry fruit. After 10 to 20% of honey coating, the primary drying ($95^{\circ}C$, 5 hours) was implemented. then, the secondary drying was conducted after controlling the temperature of the far infrared dryer $60^{\circ}C$, for 10 hours. These manufacture process was able to obtain semi-dried mulberry fruit. Dry weight ratio and moisture content were around 25%, and around 16% level respectively. It was to enable long-term storage at room temperature. Therefore, it is suggested that the method of using the far-infrared drying machine to manufacture semi-dried mulberry fruit can be a way to improve the farm income if applied to the farm.

A study on the heat and mass transfer for the drying time in spray freezing drying process was experimentally presented in this paper. A spray freezing dryer for the production of an inhalable powder medicine is developed and an albumin solution as protein specimen is adopted. The freeze-drying for the albumin solution is tested in three different height of the particles piled up in a tray such as 2 mm, 5 mm, 7 mm, and the drying time is estimated as 10 h, 15 h, 22 h. From this results, the correlation is suggested and the drying time with various height of the particles piled up in a tray can be estimated. The assessment on the drying time is conducted thought a microbalance and the rate of water content is measured. The results based on temperature and weight are compared. The difference of the results happens due to the heat transfer from the lateral side of the vial. It is thought that the better estimation in drying time can be predicted by considering the heat transfer effect.

The effects of drying temperature on the microstructure of porous W fabricated by the freeze-casting process of tert-butyl alcohol slurry with WO₃ powder was investigated. Green bodies were hydrogen-reduced at 800℃ for 1 h and sintered at 1000℃ for 6 h. X-ray diffraction analysis revealed that WO₃ powders were completely converted to W without any reaction phases by hydrogen reduction. The sintered body showed pores aligned in the direction of tert-butyl alcohol growth, and the porosity and pore size decreased as the amount of WO₃ increased from 5 to 10vol%. As the drying temperature of the frozen body increased from -25℃ to -10℃, the pore size and thickness of the struts increased. The change in microstructural characteristics based on the amount of powder added and the drying temperature was explained by the growth behavior of the freezing agent and the degree of rearrangement of the solid powder during the solidification of the slurry.

본 연구는 식혜의 편이성, 유통성, 저장성을 향상시키기 위하여 피막물질을 첨가하고 분무건조를 통하여 분말화를 하고자 하였다. 최적조건 설정을 위하여 반응표면분석법을 이용하였으며 독립변수는 피막물질 maltodextrin의 첨가량(%), 분무건조기의 inlet 온도($^{\circ}C$) 그리고 분무건조기내 시료의 공급속도(mL/min)로 설정하였으며 이에 따라 영향을 받는 반응변수는 분말의 흡습량(g), 용해도(%), 입자크기(${\mu}m$)로 설정하였다. 각 반응변수에 따른 회귀식은 흡습량은 p<0.001, 용해도는 p<0.05, 입자크기는 P<0.001 수준에서 유의성이 인정되었다. 그리고 각 독립변수와 종속변수의 영향을 나타내는 반응표면그래프를 이용하여 최적 분말화 조건을 예측한 결과 각 종속변수 최적점인 MD 22%, 분무건조기의 inlet 온도 $140^{\circ}C$ 그리고 분무건조기 내로 유입되는 시료의 공급속도는 51 mL/min로 예측되었다.

Response surface methodology (RSM) is a statistical procedure frequently used for optimization studies. The purpose of this study was to determine the optimal spray drying condition for manufacturing Sikhye powder using RSM. Independent variables included the additive contents of maltodextrin (MD), inlet temperature, and velocity of sample feed velocity. The dependent variables were water uptake (g), solubility (%) and particle size (${\mu}m$). Regression models describing the changes of water uptake (g), solubility (%) and particle size (${\mu}m$) with respect to the independent variables were statistically significant with coefficients of determination, $R^2$, greater than 0.9. The results indicated that the inlet temperature of the spray dryer was the most important independent variable that affected the water uptake (g), while the additive content of MD and the sample feed velocity had maximum effects on the solubility (%) and particle size (${\mu}m$) of the Sikhye powder, respectively. The optimum final product was expected to have the lowest possible water uptake (g) and particle size (${\mu}m$) but the highest possible solubility (%). In conclusion, the best spray drying conditions were as follows: additive MD content, 22%; inlet temperature, $140^{\circ}C$ ; and spray dryer sample feed velocity, 51 mL/min.

The effects of drying temperature on the microstructure of porous W fabricated by the freeze-casting process of tert-butyl alcohol slurry with WO3 powder was investigated. Green bodies were hydrogen-reduced at 800oC for 1 h and sintered at 1000oC for 6 h. X-ray diffraction analysis revealed that WO3 powders were completely converted to W without any reaction phases by hydrogen reduction. The sintered body showed pores aligned in the direction of tertbutyl alcohol growth, and the porosity and pore size decreased as the amount of WO3 increased from 5 to 10v ol%. As the drying temperature of the frozen body increased from -25oC to -10oC, the pore size and thickness of the struts increased. The change in microstructural characteristics based on the amount of powder added and the drying temperature was explained by the growth behavior of the freezing agent and the degree of rearrangement of the solid powder during the solidification of the slurry.

과산화수소를 일원 추진제로 사용하는 추력기용 촉매의 건조 조건에 따른 성능 변화에 대한 실험을 수행하였다. 사용한 촉매는 백금이며 촉매 지지체는 펠렛 타입의 알루미나이다. 일반적인 촉매 제작 방법인 증발건조법을 사용하였으며, 이 때 건조 조건에 따른 촉매의 성능을 평가하였다. 촉매 제작 조건 중 pH 값이 낮은 경우 촉매 제작이 유리하였기 때문에 다양한 산성 용액에서 촉매를 담지 해 실험을 수행하였다. 건조 온도는 각각 25, 50, 70, $90^{\circ}C$이며 실험 결과 $90^{\circ}C$에서 건조한 경우 높은 성능을 보임을 알 수 있었다. 이는 빠른 증발속도로 인해서 백금이 결정화를 이루지 못하고 고르게 분산되었기 때문으로 판단된다.

In this paper, performance evaluation of catalyst for hydrogen peroxide thruster with drying condition is described. Platinum was selected as a catalyst, and alumina of pellet type was chosen as a catalyst support. Evaporation method known as general method for catalyst production was used to make the catalyst. From previous experiments, it is favorable during catalyst making process that solution of active material has low pH level. Therefore, some kinds of low pH level solution had been tested. The drying temperatures are 25, 50, 70, and $90^{\circ}C$. From experimental results, it shows better performance that drying temperature was $90^{\circ}C$ since the catalyst particle could not be crystallized but be evenly spreaded out due to the rapid evaporation of solvent.

This paper studies on the behaviors of decomposition products from DCP according to various drying conditions of DCP. The decomposition products formed during crosslinking reaction have an harmful influence on XLPE. Especially explosive gases like methane which is one of decomposition products may cause explosion accident. We used the Gas Chromatography and Gas sensor for decomposition gases analysis, FT-IR for investigating the behaviors of decomposition products remained in XLPE.

Decomposition products by crosslinking reaction of PE using Dicumylperoxide(DCP) should influence on the electrical properties in XLPE. This paper studies on Behaviors of Decomposition products and Electrical Treeing ding to Drying condition. We used the Gas Chromatography for Decomposition Gases analysis FT-IR for investigating the behaviors of Decomposition products remained in XLPE Break Down Voltage Tester for Electrical Treeing measurement.

본 연구는 화재시 고강도 콘크리트의 폭렬발생에 대한 영향요인을 검토한 것으로써, 폭렬에 직접적인 상관관계에 있는 물-결합재비, 공기량 및 함수율 등을 PP섬유의 혼입률과 함께 변화시켜 실험을 실시하였다. 실험결과 유동특성은 섬유의 혼입률이 0.05 vol.% 증가함에 따라 약 11%정도 감소하는 것으로 나타났고, 공기량이 10%인 경우는 다량의 AE제 사용에 기인하여 섬유의 혼입률과 상관없이 거의 유사한 유동성을 나타냈다. 강도특성으로는 W/B 15, 25 및 35%일 경우 100, 80 및 60 MPa이상으로써 고강도 범위로 나타났으며, 공기량 변수의 경우는 H-air가 L-air에 비해 약 1/2배 정도로 낮게 나타났다. 폭렬특성으로는 KS F 2257-1에 규정되어 있는 표준가열곡선에 의해 1시간 내화시험을 실시한 결과, W/B는 고강도로 W/B가 낮을수록 심하게 발생하는데, 15%를 제외한 모든 경우에서 전반적으로 PP섬유의 혼입률 0.10 vol.%에서 폭렬이 방지되는 것으로 나타났고, 공기량을 10%로 많이 함유하는 시험체와 완전건조 시킨 시험체는 0.05 vol.% 혼입시에도 폭렬현상이 발생하지 않는 것으로 나타났다.

This paper is to investigate the affecting factors on spalling of the high strength concrete including W/B, air content and moisture condition as well as PP fiber contents subjected to fire. An increase with 0.05% of PP fiber resulted in a reduction of slump flow by as much as 11%. Ten percent of air contents due to excessive amounts of AE agent does not lead to variance of slump flow, regardless of PP fiber content. For the effect of the compressive strength, high strength concrete with 15, 25 and 35% of W/B gained 60 MPa~100 MPa of the compressive strength. High strength concrete with H-air had half of compressive strength of that with L-air due to large amount of air. Fire test was conducted in accordance with KS F 2257-1 for 1 hour. Spalling did not occur with all specimens containing more than 0.10% of PP fiber except those with 15% of W/B. Moreover, it is interesting to note that the specimens with more than 10% of air content and with oven dried condition, respectively, had no spalling even if the content of PP fiber is 0.05 vol.%.