• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.97-100
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• 2006

This paper report the result of the investigation on the properties of drying shrinkage for alkali-activated slag mortar in different relative humidity Commonly we know that drying shrinkage means lost more moisture but the mechanism of drying shrinkage of alkali activated slag mortar is not entirely due to the quantity of weight loss of water from mortar. pore size distribution and the calcium silicate hydrate gel characteristics have a critical influence on the magnitude of drying shringkage to alkali activated slag mortar. For this investigation, Ca(OH)2, Na2SiO4 were as alkali activator with 5 dosages(6%, 9%, 12%, 15%, 20%) and curing condition were three different relative humidity(35%, 65%, 95%) at $20{\pm}3^{\circ}C$

• 공업화학
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• 제31권2호
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• pp.208-214
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• 2020

본 연구에서는 식물세포 Taxus chinensis로부터 수분 제거를 통한 바이오매스 보관 및 추출 효율 향상을 위하여, 마이크로웨이브를 이용한 건조의 특성 및 메커니즘을 조사하였다. 마이크로웨이브 파워가 100, 200, 300 W로 증가함에 따라 수분의 제거 효율은 증가하였다. 실험 데이터를 대표적 동역학적 건조 모델에 적용할 때, Page 모델과 modified Page 모델이 가장 적합한 것으로 결정되었다. 열역학적 파라미터는 마이크로웨이브를 이용한 건조의 자발적 및 흡열특성을 나타내었으며, 건조 과정에서 무질서도는 증가함을 알 수 있었다. 마이크로웨이브 파워(100~300 W)가 증가함에 따라 수분의 유효확산계수(3.445 × 10^-9~7.163 × 10^-7 ㎡/s) 및 대류물질전달계수(3.1529 × 10^-5~1.2895 × 10^-2 m/s)가 증가하였다. 작은 비오트 수(0.3890~0.7198)를 고려할 때, Taxus chinensis의 건조 진행은 외부 확산에 의해 조절됨을 알 수 있었다.

• 펄프종이기술
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• 제43권4호
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• pp.49-58
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• 2011

The maximum drying shrinkage velocity was proposed to verify bulk and stiffness improvement mechanism during drying according to papermaking parameters. It was based on the wet-web shrinkage behavior without the restraint of wet-web during drying, so intact drying impact could be measured. Bulking agent reduced the drying shrinkage and the maximum drying shrinkage velocity, so paper bulk increased and paper strength decreased. When adding cationic starch to stock with the bulking agent for strengthening, the bulk was increased further with additional decreasing of the drying shrinkage and the maximum drying shrinkage velocity. Paper strength also increased except tensile stiffness index with decreasing the drying shrinkage and the maximum drying shrinkage velocity. When using additional strength additives for strengthening of fiber interfaces extended by bulking agent and cationic starch, amphoteric strength additive increased paper stiffness without loss of paper bulk. It was considered that the added amphoteric strength additives were cross-linked to the stretched cationic starch and this cross-linking increased elasticity of fiber-polymer-fiber interfaces without changing the drying behavior. Paper bulk could be increased with decreasing the maximum drying shrinkage velocity. The drying shrinkage of paper also could be controlled by fiber-to-fiber bonding interfaces by the bulking agent. In this case, paper strength including stiffness was decreased by reducing fiber-to-fiber bonding but it could be improved by strengthening fiber-to-fiber interfaces with polymer complex without loss of bulk.

• Journal of the Korean Wood Science and Technology
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• 제36권5호
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• pp.49-55
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• 2008

This study was carried to investigate the effects of steaming and four different drying methods on the longitudinal liquid permeability of Korean pine (Pinus koraiensis Sieb.et Zucc.) board. Four drying methods were air drying, conventional kiln drying, microwave-vacuum drying and high temperature drying. Darcy equation was used for calculating the specific permeability of the small sapwood specimens taken from the treated boards while capillary rising method was used for the heartwood specimens. The sapwood specimens were extracted with water and benzene-alcohol solution to examine the mechanism of liquid flow in treated wood. No significant correlation was found between specific permeability and the number of resin canals of the sapwood specimens. Extraction decreased the differences of specific permeabilities of the sapwood specimens between the five treatment methods. The effects of extraction on the longitudinal permeability are different between five treatments. The fluid path in heartwood was observed by dynamic observation method.

• Journal of Biosystems Engineering
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• 제33권5호
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• pp.296-302
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• 2008

The effective moisture diffusivity and its dependence on drying temperature during drying of rapeseed were experimentally investigated. The data were recorded from thin layer drying experiments at nine different combinations of drying air temperatures of 40, 50, and $60^{\circ}C$ and the relative humidities of 30, 45, and 60%. The moisture diffusion equation was analyzed using stepwise multiple regression analysis. Effective moisture diffusivities were calculated based on the moisture diffusion equation for a spherical shape using Fick's second law. The effective diffusivities during the drying of rapeseed were $l.72{\times}10^{-11}$, $2.41{\times}10^{-11}$ and $3.31{\times}10^{-11}\;m^2{\cdot}s^{-1}$ at 40, 50 and $60^{\circ}C$, respectively. The activation energy for moisture diffusion during drying was $28.47\;kJ{\cdot}mol^{-1}$. The dependence of moisture diffusivity on temperature was described by an Arrhenius-type equation. Drying occurred in the falling rate period and the internal moisture diffusion phenomenon is the governing physical mechanism of the moisture movement in the particles.

• 자원리싸이클링
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• 제19권6호
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• pp.43-50
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• 2010

에너지 위기로 인하여 석탄에 대한 관심이 증가하고 있다. 그 중에서도 저등급석탄에 대한 관심이 증가하고 있는데, 저등급석탄은 수분함량이 30~60%갱도로 수분함량이 높다. 이러한 저등급 석탄을 발전용 연료로 사용하기 위해서는 건조공정이 선행적으로 이루어져야 한다. 본 연구에서는 고정층 반응기를 이용하여 저등급석탄의 건조 반응속도론을 도출하였다. 건조반응속도는 입자크기, 주입가스 온도, 가스 유속, L/D의 영향을 변수로 하여 도출하였다. Reynold's number는 가스 유속과 석탄업자의 크기, L/D는 반응기 직경과 대상탄의 충진양을 보정하기 위해 고려하였다. 석탄의 건조 특성에서도 알 수 있듯이, 고정층 반응기를 이용한 저등급석탄의 건조에 있어서도 표면수분의 건조가 원활하며, 상 경계 반응이 적합한 메커니즘임을 확인 할 수 있었다.

• 한국식품과학회지
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• 제25권5호
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• pp.558-564
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• 1993

쌀보리를 시료로 하여 건조조건을 다르게 하여 유동층 건조특성에 영향을 미치는 외부요인에 대해서 조사한 결과를 요약하면 다음과 같다. 쌀보리의 유동층건조는 항률건조기가 없이 감률건조 1단계, 감률건조 2단계의 두 단계로 일어남을 알 수 있었다. 또한 건조속도상수는 충전량이 적을수록, 공기속도가 클수록, 공기온도가 높을수록, 상대습도가 낮을수록 켰으며, 감율건조단계에서의 건조속도상수는 Arrhenius형의 plot에서 좋은 직선관계를 나타내어 이 단계가 활성화 과정임을 알 수 있으며, 감률건조 제 1단계의 활성화 에너지는 1900ca1/gmol, 감률건조 제 2단계의 활성화 에너지는 2500ca1/gmol을 각각 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1053-1060
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• 2019

Thermal drying is a common process used in the food industry for the modification of agricultural products. However, while various studies have investigated the alteration in physiochemical properties and chemical composition after drying, research focusing on the relationship between different dehydration conditions and bioactivity is scarce. In the current study, we prepared dried ginger under nine different conditions by varying the processing time and temperature and compared their immunomodulatory effects. Interestingly, depending on the drying condition, there were significant differences in the immunestimulating activity of the dried ginger samples. Gingers processed at $50^{\circ}C$ 1h displayed the strongest activation of macrophages measured by $TNF-{\alpha}$ and IL-6 levels, whereas, freezedried or $70^{\circ}C$- and $90^{\circ}C$-dried ginger showed little effect. Similar results were recapitulated in primary bone marrow-derived macrophages, further confirming that different dehydration conditions can cause significant differences in the immune-stimulating activity of ginger. Induction of ERK, p38, and JNK signaling was found to be the major underlying molecular mechanism responsible for the immunomodulatory effect of ginger. These results highlight the potential to improve the bioactivity of functional foods by selectively controlling processing conditions.

• Journal of Nutrition and Health
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• 제8권4호
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• pp.33-37
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• 1975

This investigation was designed to determine the influence of drying methods on the free amino acids and free sugars in red pepper and to study the browning mechanism of brown-colored red pepper. Three different drying methods were employed: 1) Sun-drying at $25{\sim}28^{\circ}C$ for 15 days, 2) Drying in oven at $60^{\circ}C$ for 49 hours, and 3) Drying in oven at $90^{\circ}C$ for 8 hours. Dried and ground peels were used for the analysis of free amino acids and free sugars. The results were as follows; 1. Sixteen kinds of amino acids i.e. asparagine, methionine, and cystine etc. were identified. Total amino acid content of the sun-dried sample was not different from that of the fresh sample, but the samples dried at $60^{\circ}C$ and $90^{\circ}C$ in the oven were decreased to 24.9% and 67.4% respectively. Of amino acids identified, methionine, lysine and aspartic acid were decreased in all treatments. Especially, methionine ana aspartic acid were decreased rapidly to 71.8% and 73.3% , respectively. 2. Three kinds of free sugars i.e. glucose, fructose and sucrose were identified. The total content of free sugars was significantly decreased in each treatment. Among the reducing sugars, glucose was rapidly decreased; 65.9% for the glucose of sample dried at $90^{\circ}C$ in the oven. 3. At the higher drying temperature, the darker red color was found. Brown-color appeared at $90^{\circ}C-drying$ showed appreciable losses in carotenoid content, but the major color seems to be due to the large increase in browning compounds. 4. It was assumed that increased browning compounds of red pepper were due to the Maillard reaction which is a nonenzymatic browning process.

• 한국식품과학회지
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• 제25권6호
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• pp.764-768
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• 1993

자동으로 온도, 습도 및 중량을 감지하고, 히터, 송풍기, 가습기 및 제습기의 작동여부를 제어할 수 있는 자동 건조 시스템을 개발하여, 인삼을 시료로하여 열풍건조시의 건조온도와 건조기 내의 상대습도에 따른 건조특성을 구명하고, 각 건조조건에서의 이화학적 특성을 조사하였다. 인삼의 건조속도는 건조온도가 높고 건조기내의 상대 습도가 낮을수록 빨랐으며, 건조된 인삼의 hardness는 건조온도가 높을수록 높고, 건조실내의 상대습도는 25%에서 높았다. 건조온도가 높을수록 Hunter L value가 감소하고 a와 b value가 증가하는 경향을 보였으며, 갈변도가 높았다. 인삼의 건조과정중에 일어나는 수축은 건조온도가 높고 건조기내의 상대습도가 낮을수록 컸으며, 직경의 수축률이 길이의 수축률에 비해 컸다. 인삼의 조사포닌 함량은 건조온도와 상대습도에 영향을 받지 않았다.