• Fire Science and Engineering
• /
• v.25 no.6
• /
• pp.168-177
• /
• 2011

The combustion test for real box of AC outdoor unit has been performed in this study in order to estimate the fire hazard in multi-system type of AC outdoor unit which is currently used for commercial use. The result showed that in test, there was explosion inside of AC outdoor unit, and flame erupted and fire spread through upper side grill. And then this fire burnt the combustibles such as wires, electronic control board, heat exchange copper plate and plastics etc inside the unit, refrigerant gas pipe was burst due to fire, and accelerated the explosion and flame eruption to outside while the refrigerant was erupting. It is found in this test that the maximum heat release rate of AC outdoor unit is 5,830 kW, the maximum internal temperature measured with infrared camera and thermocouple is $1,201^{\circ}C$, maximum ambient temperature is $881^{\circ}C$, and flame rose higher than about 5 m. It is concluded that the fire in AC outdoor unit cause fire to combustibles around the unit, and may give big damage by generating the secondary fire. It is expected that the result obtained from the test on the real object may be applied to fire realization of AC outdoor unit and estimation of fire spreading to the combustibles around in the future computer simulation.

• The Korean Journal of Pain
• /
• v.6 no.2
• /
• pp.231-236
• /
• 1993

Clonidine, a centrally-acting antihypertensive agent known to reduce central sympathetic outflow and modulate presynaptic transmitter's release, has shown to suppress central noradrenergic hyperactivity induced by immobilization stress in animals, by decreasing the MAC of halothane and the dose of narcotics required to prevent reflex cardiovascular response to noxious stimuli, and to have potent analgesic properties in humans. These characteristics suggest that clonidine might be a useful adjunct to the anesthetic management of patients with preexisting hypertension. Accordingly, we determined the clinical efficacy and safety on analgesia, sedation and hemodynamic stability in the perioperative period. Thirty patients(ASA physical status II-III) with a history of arterial hypertension, scheduled for elective orthopedic surgery were randomly assigned to two groups. We applied CPA-clonidine patch($6.9\;mg/cm^2$, 0.2 mg delivered daily) or placebo patch to each groups, 48 hours prior to induction of anesthesia. Antihypertensive medication was continued until the morning of the scheduled surgery. All patients received premedication of atropine and lorazepam, and induced anesthesia with thiopental and succinylcholine, and maintained with enflurane and 50% nitrous oxide, while sustaining the BP and pulse rate at acceptable range. For the relief of pain postoperatively, diclofenac and fentanyl were administered intramuscularly on demand. The results were as follows: 1) The change of hemodynamic responses in clonidine group was less compared to the placebo group. 2) Intraoperative anesthetic requirement for enflurane in clonidine group were significantly lower than placebo group. 3) Postoperative analgetic requirement in clonidine group were significantly lower than placebo group. In clonidine group, 5 cases out of 15 cases were required no analgetics, and the incidence of administration of additional fentanyl was decreased to 5 cases, comparing with 10 cases in placebo group.

• Journal of Radiation Protection and Research
• /
• v.34 no.2
• /
• pp.87-94
• /
• 2009

Tritium is the one of the dominant contributors to the internal radiation exposure of workers at pressurized heavy water reactors (PHWRs). This nuclide is likely to release to work places as tritiated water vapor (HTO) from a nuclear reactor and gets relatively easily into the body of workers by inhalation. Inhaled tritium usually reaches the equilibrium of concentration after approximately 2 hours inside the body and then is excreted from the body with a half-life of 10 days. Because tritium inside the body transports with body fluids, a whole body receives radiation exposure. Internal radiation exposure at PHWRs accounts for approximately 20-40% of total radiation exposure; most internal radiation exposure is attributed to tritium. Thus, tritium is an important nuclide to be necessarily monitored for the radiation management safety. In this paper, metabolism for tritium is established using its excretion rate results in urine samples of workers at PHWRs and an effective half-life, a key parameter to estimate the radiation exposure, was derived from these results. As a result, it was found that the effective half-life for workers at Korean nuclear power plants is shorter than that of International Commission on Radiological Protection guides, a half-life of 10 days.

• Journal of the Korean Geographical Society
• /
• v.47 no.1
• /
• pp.79-97
• /
• 2012

This study examines on the impact of biodiversity in circular greenspace of Cheongju city since 2002 greenbelt release. Research has carried out to investigate the biotope pattern change with landscape fragmentation. Major landscape fragmentation has occurred with development of residential sector and build-up of major highways. Settlement has been expanded to the entire area connected to urban district excluding the eastern forest. North-south district shows high road density, where inter-regional roads meet in the cross-section. It is found that landscape fragmentation impact on species richness as well as population size of the species varies depending on the animal species. The birds show high species richness in N2, N3, N4, S2(north-south zone) even with high fragmentation rate. This can be explained that birds can access to aquatic environment where they can find abundant food resources. The amphibians and the reptiles show almost no zonal variation in species richness than the birds. The more a zone fragmented in small patches, the species richness of the amphibians and the reptiles also tends to be declined. Information accumulation on biodiversity for integrating landscape planning in urban planning, various level of community participation in decision making process, and cross border cooperation with neighbouring Cheongwon-gun will be required for sustainable greenspace management of Cheongju City.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1115-1123
• /
• 2008

When constructing projects such as road embankments, bridge approaches, dikes or buildings on soft, compressible soils, significant settlements may occur due to the consolidation of these soils under the superimposed loads. The compressibility of the soil skeleton of a soft clay is influenced by such factors as structure and fabric, stress path, temperature and loading rate. Although it is possible to determine appropriate relations and the corresponding material parameters in the laboratory, it is well known that sample disturbance due to stress release, temperature change and moisture content change can have a profound effect on the compressibility of a clay. The early research of Tezaghi and Casagrande has had a lasting influence on our interpretation of consolidation data. The 24 hour, incremental load, oedometer test has become, more or less, the standard procedure for determining the one-dimensional, stress-strain behavior of clays. An important notion relates to the interpretation of the data is the ore-consolidation pressure ${\sigma}_p$, which is located approximately at the break in the slope on the curve. From a practical point of view, this pressure is usually viewed as corresponding to the maximum past effective stress supported by the soil. Researchers have shown, however, that the value of ${\sigma}_p$ depends on the test procedure. furthermore, owing to sampling disturbance, the results of the laboratory consolidation test must be corrected to better capture the in-situ compressibility characteristics. The corrections apply, strictly speaking, to soils where the relation between strain and effective stress is time independent. An important assumption in Terzaghi's one-dimensional theory of consolidation is that the soil skeleton behaves elastically. On the other hand, Buisman recognized that creep deformations in settlement analysis can be important. this has led to extensions to Terzaghi's theory by various investigators, including the applicant and coworkers. The main object of this study is to suggestion the modified compression index value to predict settlements by back calculating the $C_c$ from different numerical models, which are giving best prediction settlements for multi layers including very thick soft clay.

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.351-355
• /
• 2010

This study was conducted to determine the relationship of larval density of tobacco cutworm, Spodoptera litura (Fabricius) to damage in greenhouse sweet pepper. Laboratory experiments, cage experiments by artificial release and field investigation were carried out in 2008. The leaf consumption rate increased greatly with larval development. The damaged leaves had several round or oval shape holes on the surface or lost certain parts of them, and the fruit damaged had a conspicuous hole on the surface or scar marks around the calyx. In the field investigation, fruit damage was highly correlated with larval densities and reached 3.5% damage at maximum. Cage experiments showed that numbers of non-marketable fruit increased as increasing larval densities released. The larval density at two weeks before harvest had a high relationship with the percentage of damaged-fruit at harvest. Corresponding larval density caused 1, 3, 5% of damaged-fruit was 0.2, 0.5, 0.8 larvae per plant, respectively.

• Korean journal of applied entomology
• /
• v.59 no.3
• /
• pp.257-264
• /
• 2020

The purpose of this study was to investigate the attraction distance range of pheromone traps used in the control of stink bugs, which are a problem in persimmon orchards, and the effects of sticky traps in increasing the efficiency of pheromone traps. Labeled individuals were released and then recaptured on pheromone and sticky traps. Riptortus clavatus was attracted to pheromone traps up to 60 m away. The capture rates of R. clavatus on sticky traps were 35%, 27%, 34%, 2.9%, and 0.6% after 0, 1, 2, 3, and 4 weeks To improve clarity, II have added this information from the details shown in the figures. Please check whether you agree.of exposure of the traps to the environment, respectively. Besides, when both pheromone and sticky traps were used at the same time following the release-recapture method, the capture rate of R. clavatus was 12 times higher than that by using pheromone traps only.

• Food Science and Preservation
• /
• v.18 no.4
• /
• pp.517-526
• /
• 2011

The physical properties of dough with different levels (2, 4, 6, and 8%) of bamboo leaf powder were inverstigated. The bamboo leaf powder had a moisture content of 5.15%, a crude protein content of 10.48%, a crude fat content of 5.21%, a crude fiber content of 22.74%, and a crude ash content of 17.63%. The following parameters showed significant differences with the increase in the amount of bamboo leaf powder added. The gelatinization degree measured by a rapid visco-analyzer increased with the increase in the powder amount added. In the values of the farinogram parameter for dough consistency, the elasticity of the dough increased with the increase in the powder amount added. The alveogram values showed a similar tendency as those of the farinogram in terms of elasticity, absorption rate, absorption time and stability. In the rheofermentometer analysis, the volume decreased with the increase in the powder amount added, but no significant difference was found at up to 4% powder amount addition, suggesting that the about 2% and up to 4% powder amount addition is moderate.

• Korean Journal of Food Science and Technology
• /
• v.30 no.6
• /
• pp.1399-1403
• /
• 1998

We isolated wild lactic acid bacteria from kimchi and identified as Lactobacillus brevis by using API 50 CHL Kit, some morphological and physiological tests. In order to evaluate the acid tolerance of Lactobacillus brevis, its survivals rate, glycolysis assay, membrane permeability, and pH profiles of $H^+-ATPase$ were also determined. When Lactobacillus brevis were incubated in Lactobacilli MRS broth adjusted to various levels of pH for 2 hours, the decreases in its population at pH 4.0 and 3.0 were about 2.61 log cycles/mL and 5.89 log cycles/mL, respectively, but there was no decrease at pH 6.0 and 5.0. Glycolysis by Lactobacillus brevis had optimal pH about 6.5 and glucose degradation was reduced by 50% at a pH of 5.2. $Mg^{++}$ release from Lactobacillus brevis cells in medium with pHs of 4.0 and 3.0 was 24.3 and 71.2% of totals, respectively. The $H^+-ATPase$ of Lactobacillus brevis showed a maximal activity between pH values of approximately 6.5 to 7.0.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.2
• /
• pp.1013-1019
• /
• 2011

In this paper, simulation works for a multi-stage cascade refrigeration cycle using propane, ethylene and methane as refrigerants have been performed for the liquefaction of natural gas using Peng-Robinson equation of state built-in PRO/II with PROVISION release 8.3. The natural gas feed compositions were supplied from Korea Gas Corporation and the flow rate was assumed to be 5.0 million tons per annual. Supply temperature for propane refrigerant was fixed as $-40^{\circ}C$, that for ethylene refrigerant as $-95^{\circ}C$, and that for methane refrigerant as $-155^{\circ}C$. For the multi-stage refrigeration cycle, three-stage refrigeration was assumed for propane refrigeration cycle, two-stage refrigeration for ethylene refrigeration cycle and three-stage refrigeration for methane refrigeration cycle. Natural gas was finally cooled and liquefied to $-162^{\circ}C$ by Joule-Thomson expansion. Conclusively, 91.71% by mole of the natural gas liquefaction ratio was obtained through a cascade refrigeration cycle and Joule-Thomson expansion and 0.433 kW of compression power was consumed for the liquefaction of 1.0 kg/hr of natural gas.