• Journal of the Korean Society of Food Science and Nutrition
• /
• v.28 no.6
• /
• pp.1283-1287
• /
• 1999

This study was carried out to develop new processed food from cherry tomatoes. The dried cherry tomatoes were prepared by using a sequence of osmotic dehydration, air drying, vacuum drying and freeze drying. The moisture contents of dried cherry tomato products by nontreatment and osmosis treatment were about 11~13% and 7.5~ 10%, respectively. The vitamin C contents of the dried product after osmotic dehydration were higher than those of the dried products by nontreatment. The vitamin C content of the freezing dried product was the highest of the others. The vacuum dried product by nontreatment was retained color of fresh fruit in the change of color. The ΔE value of the air dried product was lower than those of the others. As a result to microscopic analysis, fresh cherry tomato was observed regular tissue, while cherry tomato treated by osmosis was observed a cell collapse following the loss of water. The dried product had cell shrinkage and dense tissue. And the cell wall of dried products after osmotic dehydration were much more damage than those of nontreatment dried product. The palatability of the air dried product was the best of three drying methods. The dried cherry tomatoes treated by osmosis were superior to the dried cherry tomatoes by nontreatment.

• The Korean Journal of Pain
• /
• v.9 no.1
• /
• pp.215-218
• /
• 1996

Frostbite involves freezing of tissues and usually affects the distal aspects of the extremities or exposed parts of the face. such as the ears, nose, chin, and cheeks. It produces tissue injury by ice crystal formation between the cells, cellular dehydration, and microvascular occulsion. There are four degrees of frostbite. First degree is accompanied by erythema and edema; second degree, by vesiculation, blistering, and eschar formation; third degree, by hemorrhagic blistering and bluish gray discoloration; and fourth degree, by injury to subcutaneous tissue, muscle, tendon, and bone leading to mottled, dry, black, and necrotic changes. We successfully treated 2 patients suffering from frostbite by performing sympathetic ganglion block with pure alcohol. We concluded sympathetic ganglion block is one of the most effective treatments for frostbite.

• Journal of The Geomorphological Association of Korea
• /
• v.24 no.3
• /
• pp.47-59
• /
• 2017

This study aims to analyze geomorphologically Jaein Falls in Hantangang Lava Plateau for the landform structure, landform classification, falls dissection and recession. The height and recession length of the Falls are approximately 18m and 340m. after dissection valley arrive at area of the Jijangbong Volcanic Rock Complex of Mesozoic era, the fall will disappear. The structure of the dissection valley shows totally well vertical columnar joint near falls and plunge pool, colluvial talus deposits toward lower reach by the freezing-thawing and wet-dry activities, and alluvial cone and delta in estuary to Hantangang River. The Falls' age date and recession rate in the valley maybe relate to the age of the lava plateau. The estimated recession rate of the fall should be 8.75m/ka to 2.3m/ka, depending on the age 500ka to 40ka in lava plateau.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.5
• /
• pp.843-851
• /
• 2022

This paper was conducted to study the conditions for the manufacture and operation of artificial snow removal and ice-making test facilities so that the test equipment can be tested in a low-temperature environment using the polar environment performance test facility. The polar environment performance test Facility is designed to artificially simulate extreme environments up to -65 ℃, and is a mid-to-large low-temperature environment test facility that can perform performance tests on offshore plant equipment, ships, leisure, and offshore structures. To verify the safety of deck work of ships operating in polar environments, artificial snow removal and artificial ice making devices were manufactured, and we conducted research on various operating environments using these facilities. For the efficient operation of artificial snow and ice making facilities, it is important to continuously supply dry air, and it has been found that installing an additional heater at the tip of the nozzle is effective in preventing freezing.

• Journal of Environmental Impact Assessment
• /
• v.32 no.6
• /
• pp.473-487
• /
• 2023

Korea's multi-purpose dams, which were constructed in the 1970s and 1980s, have a single outlet located near the bottom for hydropower generation. Problems such as freezing damage to crops due to cold water discharge and an increase the foggy days have been raised downstream of some dams. In this study, we analyzed the effect of water intake depth on the reservoir's water temperature stratification structure and outflow temperature targeting Hapcheon Reservoir, where hypolimnetic withdrawal is drawn via a fixed depth outlet. Using AEM3D, a three-dimensional hydrodynamic water quality model, the vertical water temperature distribution of Hapcheon Reservoir was reproduced and the seasonal water temperature stratification structure was analyzed. Simulation periods were wet and dry year to compare and analyze changes in water temperature stratification according to hydrological conditions. In addition, by applying the intake depth change scenario, the effect of water intake depth on the thermal structure was analyzed. As a result of the simulation, it was analyzed that if the hypolimnetic withdrawal is changed to epilimnetic withdrawal, the formation location of the thermocline will decrease by 6.5 m in the wet year and 6.8 m in the dry year, resulting in a shallower water depth. Additionally, the water stability indices, Schmidt Stability Index (SSI) and Buoyancy frequency (N²), were found to increase, resulting in an increase in thermal stratification strength. Changing higher withdrawal elevations, the annual average discharge water temperature increases by 3.5℃ in the wet year and by 5.0℃ in the dry year, which reduces the influence of the downstream river. However, the volume of the low-water temperature layer and the strength of the water temperature stratification within the lake increase, so the water intake depth is a major factor in dam operation for future water quality management.

• Journal of Venture Innovation
• /
• v.5 no.2
• /
• pp.85-99
• /
• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

• Korean Journal of Weed Science
• /
• v.16 no.2
• /
• pp.114-121
• /
• 1996

This study was conducted to investigate seed germination, seedling growth, and responses to herbicides of Bidens tripartita L. When the field-collected seeds were stored under a dry-room temperature, dry-low temperature, wet-low temperature, or dry-high temperature condition, no seeds were germinated in a growth chamber with 14 hr photoperiod up to 35 days after the storage. Exceptionally, however, some seeds stored under a wet-room temperature condition were germinated after 25 days of the storage. This might be due to the fact that the seed coats were damaged by fungi which developed during the storage. Seeds stored under a wet-low temperature condition (stratification) began to be germinated after 3 months of the storage and the germination rate increased with a prolonged stratification. Almost all seeds were germinated after 9 months of the stratification. These results suggest that the dormancy of B. tripartita L. seeds relate to the seed coat and thus several attempts were made to induce seed germination through damaging or weakening the seed coat. Freezing($-20^{\circ}C$), drying($100^{\circ}C$), or swelling($40^{\circ}C$) of the seeds was not effective to induce the germination. Treatments of concentrated sulfuric acid, $KNO_3$, or gibberellin to the seeds had no effect on inducing the germination. However, ethrel had a stimulatory effect on the germination of the seeds with an optimum concentration of 250ppm. A seed cutting was also effective to induce the germination, but seedlings from the seeds had cutted cotyledons. Germination of the stratified seeds varied with the temperature condition to which they were subjected, but not with light. The germination rate was the highest at 35 - $40^{\circ}C$. Although the seeds were not able to germinate under a submerged condition, seedlings after 2-leaf-stage exhibited better growth under a submerged or a subirrigated condition than under an upland condition. Among the herbicides tested, pyrazosulfuton-ethyl, linuron, and bentazone were found to be effective for controlling B. tripartita L., having more herbicidal effect with an earlier application.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.14
• /
• pp.97-109
• /
• 1973

1. The relatively lower prehardening temperature was more effective on increase of the hardiness of the intermediately hardy varieties than the higher one but either the extremely hardy or nonhardy varieties did not respond to the temperature as much as the intermediate types. 2. Five degree Centigrade was generally more favorable than $2^{\circ}C$ on hardening of the plants, especially when frozen at higher temperature for shorter duration. 3. It appears that photoperiod during prehardening and hardening did not play so important role as temperature on the hardiness. 4. The higher the soil moisture content, the higher the frost injury occurred. 5. Application of nitrogen increased markedly the hardiness and % DM of the plants. Percentage of dry matter of young seedlings might be used as an easy and rough criterion for evaluating hardiness since there was a highly significant regression of varietal frost injury on the %DM. 6. Four days appeared to be enough for hardening of plants although the plants increased gradually the hardiness as duration of hardening extended. Dehardening of the plants at relativity higher temperature took place rapidly within one to four days. 7. Under this controlled environment, freezing at about $-8^{\circ}C$ for 24 hours seemed the best for the purpose of evaluating the hardiness to low temperature. 8. It is believed that assessment of frost injury should be done at least one week after freezing. Some varieties showed strong ability to recover from the damage as recovery period was extended. 9. As a whole, Cd 80 and 83 were the most hardy and followed by Cappelle and Maris Otter. Four. winter oats varieties and Jufy I belonged to the intermediate type while the other three spring varieties were nonhardy at all. Peniarth was comparable with Maris Otter in hardiness. S 147 appeared the least hardy among the winter oats varieties. 10. It is evident that water-soluble carbohydrate content is associated with the hardiness to some extent but not primary factor involved in hardiness.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.4
• /
• pp.287-294
• /
• 2019

GGBFS(Ground Granulated Blast Furnace Slag) has been widely used in concrete for its excellent resistance chloride and chemical attack, however cracks due to hydration heat and dry shrinkage are reported. In many International Standards, GGBFS with low fineness of 3,000 grade is classified for wide commercialization and crack control. In this paper, the mechanical and durability performance of concrete were investigated through two mix proportions; One (BS) has 50% of w/b(water to binder) ratio and 60% replacement ratio with low-fineness GGBFS, and the other (TS) has 50% of w/b and 60% replacement ratio with 4000 grade and FA (Fly Ash). The strength difference between TS and BS concrete was not great from 3 day to 91 day of age, and BS showed excellent performance for chloride diffusion and carbonation resistance. Two mixtures also indicate a high durability index (more than 90.0) for freezing-thawing since they contain sufficient air content. Through improvement of strength in low fineness GGBFS concrete at early age, mass concrete with low hydration heat and high durability can be manufactured.

• Journal of the Korean GEO-environmental Society
• /
• v.20 no.1
• /
• pp.67-74
• /
• 2019

Frost heave is one of the representative engineering characteristics in cold regions. In South Korea, which is located in seasonal frost area, structural damage caused by frost heave and thaw happens and the need for research on the frost heave is increasing. In this paper, newly developed transparent temperature-controllable cell is used to focus on the frost heave. Frost susceptible artificial soil is used to analyze water intake rate which is one of the important factors in frost susceptibility criteria. Frost heave rate and water intake rate have similar behavior after heave by freezing of pore water converges. O-ring installed in the upper pedestal to measure water intake rate generates side friction between the inner wall of the freezing cell and O-ring, thereby hindering frost heave. Therefore, the frost susceptibility criteria using the water intake rate is not reliable. It is appropriate to use frost heave rate which has similar behavior with water intake rate. Frost heave tests were performed under two different specimen heights. Overburden pressure, temperature gradient and dry unit weight were set under similar state. Based on laboratory testing results, frost heave is independent on the specimen height.