• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.10-18
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• 2012

A high airtightness is required for the residential spaces constructed recently to save cooling and heating energy through improving insulation performance. Because the chances to release steam formed by human activity in building and inflow of water vapor in outdoor air to residential space are reduced, the natural humidity control performance of interior materials has become more important. In this study, hygroscopic performance of thermo-physically treated wood (Pinus koraiensis) was estimated. At various relative humidity condition, the water vapor adsorption and desorption rates of wooden materials were measured as well as equilibrium moisture content. Effects of roughness and surface microstructure as physical factors and functional groups as chemical factors on the hygroscopicity were analyzed. It is expected that the results from this study and further study of measuring moisture generation in residential spaces could contribute to install a system for evaluating the hygrothermal performance of wooden building.

• Journal of the Korean Society of Food Culture
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• v.23 no.5
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• pp.582-594
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• 2008

This study aimed at evaluating current sanitation management performances in Korean-Food restaurants by their operation types and to develop sanitary training posters based on the risk factors, in an attempt to improve the level of sanitation management in Korean food service facilities. Eighteen Korean-food restaurants that are managed by franchisor, franchisees as well as self-managed with large-scale and small-scale restaurants in Seoul and Gyeonggi-Do, were evaluated by on-the-spot inspectors with an auditing tool consisting of three dimensions, nine categories and thirty four items. Data were analyzed using SPSS. The total score of each group showed that restaurants managed by franchisees ranked the highest (59 out of 100 points), while self-managed, small-scale restaurants ranked the lowest (44 out of 100 points). In the categorization of sanitation management compliance, the dimensions of food hygiene during production recorded the lowest compliance rate of 47.7% (22.89/48.0 points) followed by the dimension of environmental hygiene 59.3% (20.17/34.0 points) and personal hygiene 60.5% (10.89/18.0 points). This indicated the need for urgent improvement. The items which showed the lowest compliance rates were 'proper thawing of frozen foods' (0%), 'notifying and observing heating/reheating temperature' (6%), 'using of hand-washing facility and proper hand-washing' (33%), 'monitoring temperature of frozen-foods and cold-foods' (35%), and 'prevention of cross-contamination' (36%) among thirty four items. Self-managed, small-scale restaurants, in particular, needed to improve sanitary practices such as 'sanitation education for employee', 'verifying the employee health inspection reports', 'storing food on the shelves 15 cm distance away from the wall', 'suitability of ventilation capacity of hoods' and 'cleanliness of drainage'. On the basis of the findings of this study, we developed sanitary training posters, especially for small-scale restaurant operators. This could be an effective tool to educate food service employees on sanitary knowledge and principles and could be used to improve the existing sanitary conditions in Korean food service facilities.

• Advances in nano research
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• v.16 no.4
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• pp.325-340
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• 2024

There are several novel uses for dispersing many nanoparticles into a conventional fluid, including dynamic sealing, damping, heat dissipation, microfluidics, and more. Therefore, melting heat and mass transfer characteristics of a 3-D MHD Hybrid Nanofluid flow over a rotating disc with presenting dufour and soret effects are assessed numerically in this study. In this instance, we investigated both ferric sulfate and molybdenum disulfide as nanoparticles suspended within base fluid water. The governing partial differential equations are transformed into linked higher-order non-linear ordinary differential equations by the local similarity transformation. The collection of these deduced equations is then resolved using a Chebyshev spectral collocation-based algorithm built into the Mathematica software. To demonstrate how different instances of hybrid/ nanofluid are impacted by changes in temperature, velocity, and the distribution of nanoparticle concentration, examples of graphical and numerical data are given. For many values of the material parameters, the computational findings are shown. Simulations conducted for different physical parameters in the model show that adding hybrid nanoparticle to the fluid mixture increases heat transfer in comparison to simple nanofluids. It has been identified that hybrid nanoparticles, as opposed to single-type nanoparticles, need to be taken into consideration to create an effective thermal system. Furthermore, porosity lowers the velocities of simple and hybrid nanofluids in both cases. Additionally, results show that the drag force from skin friction causes the nanoparticle fluid to travel more slowly than the hybrid nanoparticle fluid. The findings also demonstrate that suction factors like magnetic and porosity parameters, as well as nanoparticles, raise the skin friction coefficient. Furthermore, It indicates that the outcomes from different flow scenarios correlate and are in strong agreement with the findings from the published literature. Bar chart depictions are altered by changes in flow rates. Moreover, the results confirm doctors' views to prescribe hybrid nanoparticle and particle nanoparticle contents for achalasia patients and also those who suffer from esophageal stricture and tumors. The results of this study can also be applied to the energy generated by the melting disc surface, which has a variety of industrial uses. These include, but are not limited to, the preparation of semiconductor materials, the solidification of magma, the melting of permafrost, and the refreezing of frozen land.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.74-93
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• 2019

The Bird Track Site in the Haman Formation in Yongsanri (Natural Monument No. 222) was reported on the named Koreanaornis hamanensis and Jindongornipes kimi sauropod footprint Brontopodus and ichnospecies Ochlichnus formed by Nematoda. This site has outstanding academic value because it is where the second-highest number of bird tracks have been reported in the world. However, only 25% of the site remains after being designated a natural monument in 1969. This is due to artificial damage caused by worldwide fame and quarrying for flat stone used in Korean floor heating systems. The Haman Formation, including this fossil site, has lithofacies showing reddish-grey siltstone and black shale, alternately. The boundary of the two rocks is progressive, and sedimentary structures like ripple marks and sun cracks can clearly be found. This site was divided into seven formations according to sedimentary sequences and structures. The results of a nondestructive deterioration evaluation showed that chemical and biological damage rates were very low for all formations. Also, physical damage displayed low rates with 0.49% on exfoliation, 0.04% on blistering, 0.28% on break-out; however, the joint crack index was high, 6.20. Additionally, efflorescence was observed on outcrops at the backside and the northwestern side. Physical properties measured by an indirect ultrasonic analysis were found to be moderately weathered (MW). Above all, the southeastern side was much fresher, though some areas around the column of protection facility appeared more weathered. Furthermore, five kinds of discontinuity surface can be found at this site, with the bedding plane showing the higher share. There is the possibility of toppling failure occurring at this site but stable on plane and wedge failure by means of stereographic projection. We concluded that the overall level of deterioration and stability were relatively fine. However, continuous monitoring and conservation treatment and management should be performed as situations such as the physicochemical weathering of the fossil layer, and the efflorescence of the mortar adjoining the protection facility's column appear to be challenging to control.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.241-252
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• 1990

In a basic attempt to develop the prophylactic and therapeutic measures on intestinal giantcystic disease of the Israel carp, C), prinks carpio nudum, the effects of physical and chemical factors on viability or survival of the spores of Thelchcnellus kiteuei were checked in vitro by means of extrusion test on the polar filament. When the fresh spores suspended with 0.45% and 0.9% scdium chloride solution and distilled water were laid at $5^{\circ}C$ and $28^{\circ}C$ for short terms, the extrusion rates increased until the 3rd day, meanwhile when son;e of them were suspended with Tyrode's solution at $-70^{\circ}C$ the rates increased gradually until the 8th day. Viabilities of the spores suspended with 0.9% saline and added antibiotics to the suspension at $5^{\circ}C$ for long terms lasted for 997 days and 1, 256 days (presumed values) at maximum, respectively. The spores suspended with distilled water at $28^{\circ}C$ for long terms survived 152.4 days, but the spores suspended with Tyrode's solution at $-70^{\circ}C$ for long terms showed almost the same viable pattern as early freezing stages up to 780 days. The spores suspended with Tyrode's solution, frozen at $-70^{\circ}C$ and thawed at $5^{\circ}C$, showed the highest rate of extrusion of the polar filament. In the case of frozen spores, the extrusion rates during heating tend to become higher in accordance with the increase of frozen period, and the critical points of 180 day-frozen spores to be killed were generally 78.5 hr. at $60^{\circ}C$, 23.4 hr. at $70^{\circ}C$, 189.1 min. at $80^{\circ}C$ or 10.5 min. at $90^{\circ}C$. The longer the spores were frozen, the more time was needed for the death of spores after thawing; 20 days-17.4 days, 100 days-33.2 days, and 400 days-37.8 days. The longer the spores were frozen, the more time was needed for the death of spores at a conventional when they were dried air drying condition, 540 days-23.5 days, 160 days-21.0 days, and 20 days-14.4 days. On the other hand, the longer the spores were frozen, the more spores were dead rapidly when they were irradiated with 10W UV-ray; 100 days-26.0 hr, 300 days-21.9 hr, and 540 days-13.9 hr. The time needed for killing 200 days-frozen spores by various disinfectants at 1, 000 ppd was 5.2 min. by calcium oxide, 10.4 min. by potassium permanganate, 27.8 min. by malachite green and 14.3 hr. by formalin. Transient inhibitory effects of the extrusion of the polar filament were observed by various antiprotozoal and antifungal agents in the descending order of ketoconazole. metronidasole and dapsone. The above results presume that full drying, followed by spraying CaO and maintaining sunny condition for a few days on the concrete bottoms of knish farm may be an effective method for the prevention of intestinal giant.cystic disease.

• Journal of environmental and Sanitary engineering
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• v.24 no.4
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• pp.1-26
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• 2009

We conclude the following with air pollution data measured from city measurement net administered and managed in Gwangju for the last 7 years from January in 2001 to December in 2007. In addition, some major statistics governed by Gwangju city and data administered by Gwangju as national official statistics obtained by estimating the amount of national air pollutant emission from National Institute of Environmental Research were used. The results are as follows ; 1. The distribution by main managements of air emission factory is the following ; Gwangju City Hall(67.8%) > Gwangsan District Office(13.6%) > Buk District Office(9.8%) > Seo District Office(5.5%) > Nam District Office(3.0%) > Dong District Office(0.3%) and the distribution by districts of air emission factory ; Buk District(32.8%) > Gwangsan District(22.4%) > Seo District(21.8%) > Nam District(14.9%) > Dong District(8.1%). That by types(Year 2004~2007 average) is also following ; Type 5(45.2%) > Type 4(40.7%) > Type 3(8.6%) > Type 2(3.2%) > Type 1(2.2%) and the most of them are small size of factory, Type 4 and 5. 2. The distribution by districts of the number of car registrations is the following ; Buk District(32.8%) > Gwangsan District(22.4%) > Seo District(21.8%) > Nam District(14.9%) > Dong District(8.1%) and the distribution by use of car fuel in 2001 ; Gasoline(56.3%) > Diesel(30.3%) > LPG(13.4%) > etc.(0.2%). In 2007, there was no ranking change ; Gasoline(47.8%) > Diesel(35.6%) > LPG(16.2%) >etc.(0.4%). The number of gasoline cars increased slightly, but that of diesel and LPG cars increased remarkably. 3. The distribution by items of the amount of air pollutant emission in Gwangju is the following; CO(36.7%) > NOx(32.7%) > VOC(26.7%) > SOx(2.3%) > PM-10(1.5%). The amount of CO and NOx, which are generally generated from cars, is very large percentage among them. 4. The distribution by mean of air pollutant emission(SOx, NOx, CO, VOC, PM-10) of each county for 5 years(2001~2005) is the following ; Buk District(31.0%) > Gwangsan District(28.2%) > Seo District(20.4%) > Nam District(12.5%) > Dong District(7.9%). The amount of air pollutant emission in Buk District, which has the most population, car registrations, and air pollutant emission businesses, was the highest. On the other hand, that of air pollutant emission in Dong District, which has the least population, car registrations, and air pollutant emission businesses, was the least. 5. The average rates of SOx for 5 years(2001~2005) in Gwangju is the following ; Non industrial combustion(59.5%) > Combustion in manufacturing industry(20.4%) > Road transportation(11.4%) > Non-road transportation(3.8%) > Waste disposal(3.7%) > Production process(1.1%). And the distribution of average amount of SOx emission of each county is shown as Gwangsan District(33.3%) > Buk District(28.0%) > Seo District(19.3%) > Nam District(10.2%) > Dong District(9.1%). 6. The distribution of the amount of NOx emission in Gwangju is shown as Road transportation(59.1%) > Non-road transportation(18.9%) > Non industrial combustion(13.3%) > Combustion in manufacturing industry(6.9%) > Waste disposal(1.6%) > Production process(0.1%). And the distribution of the amount of NOx emission from each county is the following ; Buk District(30.7%) > Gwangsan District(28.8%) > Seo District(20.5%) > Nam District(12.2%) > Dong District(7.8%). 7. The distribution of the amount of carbon monoxide emission in Gwangju is shown as Road transportation(82.0%) > Non industrial combustion(10.6%) > Non-road transportation(5.4%) > Combustion in manufacturing industry(1.7%) > Waste disposal(0.3%). And the distribution of the amount of carbon monoxide emission from each county is the following ; Buk District(33.0%) > Seo District(22.3%) > Gwangsan District(21.3%) > Nam District(14.3%) > Dong District(9.1%). 8. The distribution of the amount of Volatile Organic Compound emission in Gwangju is shown as Solvent utilization(69.5%) > Road transportation(19.8%) > Energy storage & transport(4.4%) > Non-road transportation(2.8%) > Waste disposal(2.4%) > Non industrial combustion(0.5%) > Production process(0.4%) > Combustion in manufacturing industry(0.3%). And the distribution of the amount of Volatile Organic Compound emission from each county is the following ; Gwangsan District(36.8%) > Buk District(28.7%) > Seo District(17.8%) > Nam District(10.4%) > Dong District(6.3%). 9. The distribution of the amount of minute dust emission in Gwangju is shown as Road transportation(76.7%) > Non-road transportation(16.3%) > Non industrial combustion(6.1%) > Combustion in manufacturing industry(0.7%) > Waste disposal(0.2%) > Production process(0.1%). And the distribution of the amount of minute dust emission from each county is the following ; Buk District(32.8%) > Gwangsan District(26.0%) > Seo District(19.5%) > Nam District(13.2%) > Dong District(8.5%). 10. According to the major source of emission of each items, that of oxides of sulfur is Non industrial combustion, heating of residence, business and agriculture and stockbreeding. And that of NOx, carbon monoxide, minute dust is Road transportation, emission of cars and two-wheeled vehicles. Also, that of VOC is Solvent utilization emission facilities due to Solvent utilization. 11. The concentration of sulfurous acid gas has been 0.004ppm since 2001 and there has not been no concentration change year by year. It is considered that the use of sulfurous acid gas is now reaching to the stabilization stage. This is found by the facts that the use of fuel is steadily changing from solid or liquid fuel to low sulfur liquid fuel containing very little amount of sulfur element or gas, so that nearly no change in concentration has been shown regularly. 12. Concerning changes of the concentration of throughout time, the concentration of NO has been shown relatively higher than that of $NO_2$ between 6AM~1PM and the concentration of $NO_2$ higher during the other time. The concentration of NOx(NO, $NO_2$) has been relatively high during weekday evenings. This result shows that there is correlation between the concentration of NOx and car traffics as we can see the Road transportation which accounts for 59.1% among the amount of NOx emission. 13. 49.1~61.2% of PM-10 shows PM-2.5 concerning the relationship between PM-10 and PM-2.5 and PM-2.5 among dust accounts for 45.4%~44.5% of PM-10 during March and April which is the lowest rates. This proves that particles of yellow sand that are bigger than the size $2.5\;{\mu}m$ are sent more than those that are smaller from China. This result shows that particles smaller than $2.5\;{\mu}m$ among dust exist much during July~August and December~January and 76.7% of minute dust is proved to be road transportation in Gwangju.

• Journal of the Korean GEO-environmental Society
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• v.17 no.11
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• pp.5-14
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• 2016

The main objective of this study was to evaluate the removal properties of Cu from existing exfoliated vermiculite (EV) coated with a mixed solution of sulfuric acid and glycerol on the $580^{\circ}C$ in heating, which uses coated with glycerol of copper ions can be removed more effectively. Serial batch kinetic tests and batch sorption tests were conducted to determine the removal characteristics for Cu in aqueous solution. The result of batch kinetic test shows that removal rate, $K_{obs}$ (1/hr), of Cu are 0.579, 0.878, 3.459, and 6.578 for MEV weight 1 g (25 g/L), 2 g (50 g/L), 3 g (75 g/L), 4 g (100 g/L), respectively. In this case the initial pH of the solution was 3.26. The removal experiment according to the concentration, $K_{obs}$ (1/hr), of Cu are 1.96, 0.878, 1.25, and 1.04 for the initial concentration of 3 mg/L, 5 mg/L, 8 mg/L, 10 mg/L, and the initial pH of the solution are 3.46, 3.26, 3.10, 2.96, respectively. Influence of initial pHs on Cu removal were tested under 1g of MEV with 5 mg/L of Cu solution. $K_{obs}$ (1/hr) were increased from 0.263 (pH 3) to 0.525 (pH 5). It leads to the conclusion that the removal rates are inversely proportional to the initial Cu concentration and are increased proportional to the initial pHs. Sorption capacity of MEV was determined by batch sorption tests. The maximum sorption capacity ($Q_{max}$) obtained from Langmuir was 0.761 mg/g, Linear and Freundlich partition coefficients were 0.494 L/g and 0.729 L/g (1/n = 0.476). These results show that the MEV could be used as an excellent adsorbent for copper contained in various types of aqueous solutions.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.1
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• pp.4038-4051
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• 1976

This study was intended to provide the basic design creteria for the refrigerated storage, and to estimate the required optimum capacity of refrigerator for the different sizes and kinds of the existing fruit storage. The structural characteristics of the existing fruit storages in Pyungtaek-khun of Kyungki-do were surveyed. The average out-door air temperature during the expected storage life after harvesting, was obtained by analyzing the weather information. The heat transfer rates through the different models of storage walls were estimated. The refrigerating load required for different models of fruit storage was analyzed in the basis of out-door air temperature. The results obtained in this study are summarized as follows: 1. The fruit storages surveyed were constructed on-ground, under-ground and sub-ground type buildings. The majority of them being the on-ground buildings are mostly made of earth bricks with double walls. Rice hull was mostly used as the insulating materials for their walls and ceilings. About 42% of the buildings were with the horizontal ceiling, 22% with sloped ceiling, and about 36% without ceiling. About 60% of the storage buildings had floor without using insulated material. They were made of compacted earth. 2. There is no difference in heat transfer among six different types of double walls. The double wall, however, gives much less heat transfer than the single wall. Therefore, the double wall is recommended as the walls of the fruit storage on the point of heat transfer. Especially, in case of the single wall using concrete, the heat transfer is about five time of the double walls. It is evident that concrete is not proper wall material for the fruit storage without using special insulating material. 3. The heat transfer through the storage walls is in inverse proportion to the thickness of rice hull which is mostly used as the insulating material in the surveyed area. It is recommended that the thickness of rice hull used as the insulating material far storage wall is about 20cm in consideration of the decreasing rate of heat transfer and the available storage area. 4. The design refrigerating load for the on-ground storages having 20 pyung area is estimated in 4.07 to 4.16 ton refrigeration for double walls, and 5.23 to 6.97 ton refrigeration for single walls. During the long storage life, however, the average daily refrigerating load is ranged from 0.93 to 0.95 ton refrigeration for double walls, and from 1.15 to 1.47 ton refrigeration for single walls, respectively. 5. In case of single walls, 50.8 to 61.4 percent to total refrigerating load during the long storage life is caused by the heat transferred into the room space through walls, ceiling and floor. On the other hand, 39.1 to 40.7 percent is for the double walls. 6. The design and average daily refrigerating load increases in linear proportion to the size of storage area. As the size increases, the increasing rate of the refrigerating load is raised in proportion to the heat transfer rate of the wall. 7. The refrigerating load during the long storage life has close relationship to the out-door air temperature. The maximum refrigeration load is shown in later May, which is amounted to about 50 percent to the design refrigerating load. 8. It is noted that when the wall material having high heat transfer rate, such as the single wall made of concrete, is used, heating facilities are required for the period of later December to early February.

• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.214-222
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• 1972

In the optic,11 grade LiF crystal, the electron traps corresponding to the thermoluminescence(abbreviated to TL) glow peak develop as irradiation dose is increased. Originally the electron trap of the crystal has two levels but as the dose reaches to the order of 10$^4$rontgen, it attains five levels as observed in the TL glow curves. The five trap depths are determined from the glow peak temperatures for two different heating rates, $\theta$=6.6$^{\circ}C$/sec and 3.4$^{\circ}C$/sec. The electron trap depths have the following values E$_1$=0.79 eV, E$_2$=0.93 eV, E$_3$=1.02 eV, E$_4$=1.35 eV, E$_{5}$=1.69eV. The special feature of thermoluminescence of optical grade LiF is that the traps, except E$_1$and E$_2$corresponding to 12$0^{\circ}C$ glow peak and 15$0^{\circ}C$ glow peak for $\theta$=6.6$^{\circ}C$/sec, have severe thermal instability, namely E$_3$, E$_4$and E$_{5}$ levels disappear during bleaching process. These defects in the optical grade LiF crystal seem annealed out during the course of TL measurement. The fresh or long time unused LiF(Mg) crystal shows only two glow peaks at 17$0^{\circ}C$ and 23$0^{\circ}C$ for $\theta$=6.6$^{\circ}C$/sec, but upon sensitization with r-ray irradiation, it converts to the six glow peak state. The four electron traps, E$_1$, E$_2$, E$_3$, and E$_{6}$ created by r-ray irradiation and corresponding to the glow peaks at T=10$0^{\circ}C$ 13$0^{\circ}C$, 15$0^{\circ}C$ and 29$0^{\circ}C$ are stable and not easily annealed out thermally, The sensitization essentially required to LiF(Mg) dosimeter is to give the crystal the stable six levels in the electron trap. In optical grade LiF, the plot between logarithm of total TL output versus logarithm of r-ray dose gives more supra-linear feature than that of LiF(Mg). However, if one takes the height of 12$0^{\circ}C$ glow peak(S=6.6$^{\circ}C$/sec), instead of the total TL output, the curve becomes close to that of LiF(Mg).

• Journal of Aquaculture
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• v.11 no.3
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• pp.371-380
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• 1998

This study has been conducted to develop the techniques for spat production of the sun and moon scallop from January 1995 to December 1996. With the adult scallops collected from the Sogwipo area, spawning induction and larvae rearing were attempted several times and monthly changes of GSI were also monitored during the experimental period. The results obtained wre as follows. 1. GSI started to increase from June and showed the maximum value of 22.17 and 14.98 in female and male respectively in November, and then gradually decreased from December. 2. Spawning induction by heating method turned out to the most efficient way showing the responding rate of 64.8~91.5%. The responding temperature was $21.4~26.4{\circ}C$ which was $3.1~8.5{\circ}C$ increased from the rearing temperature of $16.3~18.3{\circ}C$. An average number of eggs spawned was $9.2{\times}10^5$ 3. the average size of eggs after fertilization was about $72{\mu}m$ in diameter. The first polar body discharge, blastula formation, and trochopore larvae appearance occurred 30 mininutes, 18 hours, and 22 hours after fertilization respectively. 4. Settling rates in various collectors were similar one another, whereas pouring larvae in the mesh was the most efficient way for larval setting. 5. The spates grew to be 1mm in their shell length for the first 50 days after fertilization and 9.6mm in 135days. 6. Correlation between shell length (SL) of the spat and the number of days (X) after spat settlement could be expressed as $SL=257.75e ^{0.0272x}$(r=0.9100).