• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.115-122
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• 2008

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.%.

• The Journal of the Korean bone and joint tumor society
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• v.10 no.2
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• pp.88-95
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• 2004

Purpose: Current treatment for osteoid osteomas is usually surgical excision of the nidus. Various minimal invasive techniques have been reported to overcome the invasiveness of the surgical excision. We treated 22 patients with osteoid osteoma by percutaneous thermoablation of the nidus under computed-tomography guidance. Materials and Methods: Twenty two consecutive patients underwent CT-guided percutaneous radio-frequency thermoablation between April 1999 and May 2004. The mean age was 26.5(7~55) years. In three cases, the diagnosis was confirmed pathologically before the prodedure while the others clinically and radiologically. Computed tomography (CT)-guided percutaneous RF ablation was performed with general or spinal anesthesia. With an RF electrode, the lesion was heated to 80 or 90 degrees C for 6(3~8) minutes. Clinical success was assessed at a mean of 30(4~62) months after the procedure at out patient clinic or by telephone interview. Results: The procedure was technically successful in all cases except a complication. Patients were discharged on 1.9 days after the procedure and resumed normal activities immediately. All patients but three (86%) remained pain free during follow-up (range 4~62 months). A second thermoablation treatment relieved the recurrent symptoms in 2 patients and the remained had persistent pain without a second prodedure. Conclusion: Percutaneous thermoablation appears to be safe and effective for osteoid osteomas, and is a minimally invasive procedure alternative to surgical resection.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.603-616
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• 2010

Based on recent dramatic increases in foodborne outbreaks in restaurants, self-managed sanitation systems are now recommended to control contributing risk factors. This study aimed to improve sanitation management practices in restaurants and had two objectives. First, we tried to develop a self-managed sanitation check-list, including risk factors contributing to foodborne illness and Korean food hygiene regulation articles. We also tried to evaluate current sanitation management practices in restaurants according to operation and restaurant type. Thirty restaurants were evaluated by on-the-spot inspectors using an auditing tool consisting of four dimensions, seventeen categories, and forty-one items. Total compliance rate categorized by operation type significantly differed between chain restaurants and self-managed restaurants, with values of 85.5% and 51.6%, respectively. Therefore, self-managed restaurants, which showed the lowest compliance rate of below 30.0%, need more strict control to improve current unsanitary management practices, specifically relating to 'sterilization of knives, chopping boards, and wiping cloths', 'sanitation training', 'not allowing access into the kitchen to outsiders', 'handling of food or utensils on shelves at a 15 cm distance away from floor', 'prevention of cross-contamination of cooked foods or vegetables', and 'records of kitchen access or inspection'. Thus, an effective food sanitation system is essential and should be implemented to improve the existing sanitary conditions in restaurants. However, the most important factor to achieving food sanitation management objectives is food handlers' self-motivation.

• Food Science and Preservation
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• v.17 no.4
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• pp.471-477
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• 2010

We explored the effects of curing and smoking conditions on the shelf life of Dombaeki (shark meat). Dombaeki cured for 12 h in an aqueous solution containing (per 100 ml) salt 5.6 g, sugar 14 g, and garlic powder 0.6 g, showed the best sensory quality among various samples cured for 0, 3, 6, 9, 12 or 24 hours. The optimum conditions for preparation of smoked Dombaeki (SD) were drying at $60^{\circ}C$ for 30 min, followed by cooking at $80^{\circ}C$ for 30 min and smoking at $65^{\circ}C$ for 40 min, as judged by sensory evaluation of taste, color, flavor, texture, and overall acceptability. The volatile basic nitrogen content of air- or vacuum-packed unsmoked Dombaeki (NSD) was above 20 mg% after storage for either 12 days or 5 weeks. However, the nitrogen contents of air- and vacuum-packed SD were less than 20 mg% after either 21 days or 10 weeks of storage at $10^{\circ}C$. The DPPH free radical-scavenging ability of SD (73.9%) was significantly higher than that of unsmoked meat (4.54%). The total polyphenol content of SD (745.6 g/g) was about 4-fold greater than that of unsmoked meat (179.5 g/g).The viable bacterial count of air- or vacuum-packed unsmoked meat was over $10^6\;CFU/g$ after storage for either 12 days or 5 weeks. However, air- or vacuum-packed SD had counts under $10^4\;CFU/g$ at all storage times tested. Changes in coliform bacterial levels paralleled those of total viable cells. The sensory quality (taste, color, flavor, appearance, texture, and overall acceptability) of SD was significantly better than that of NSD.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.278-293
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• 1998

The purposes of this study were to develop Hazard Analysis Critical Control Point-based standardized recipe applicable to cook/chilled Broiled Spanish Mackerel in school foodservice operations and to establish reasonable shelf-life limits by assessing food quality during chilled storage period of 5 days. HACCP for the production of menu items was identified in simulation study. At each critical control point, time-temperature profile was recorded and microbiological analysis was done. Also chemical analyses and sensory evaluation were conducted for 5 days of chilled storage. The results of time-temperature measurement of Broiled Spanish Mackerel by each production phase showed satisfactory condition that met the standards. Broiled Spanish Mackerel showed excellent microbiological quality from raw ingredient phase ($TPC:2.58{\pm}0.12\;Log\;CFU/g$) to holding phase ($TPC:2.70{\pm}0.42\;Log\;CFU/g$). Coliform (0.84 Log MPN/g) and fecal coliform (0.84 Log MPN/g) were detected from marinating phase ($TPC:3.82{\pm}0.52\;Log\;CFU/g$). After heating, only few mesophiles were detected ($TPC:1.83{\pm}0.49\;Log\;CFU/g$). No psychrophiles, coliforms and fecal coliforms were detected. In the phases after rapid chilling, during chilled storage and after reheating and distribution, almost none of the above microbes were detected. Salmonella and Listeria monocytogenes were not detected in all production phases. The pH immediately after cooking was 6.65 and then increased significantly to 6.81 on the third day of chilled storage (p<0.001). Acid value did not show significant changes while total volatile based nitrogen (TVBN) dramatitically increased during storage periods (p<0.01). In the result of sensory evaluation, general acceptability points had been rated high in the first day of storage, and then, the points were decreased significantly on the third day (p<0.05). General acceptability points ranged from 8.86 to 10.68. Accordingly, Broiled Spanish Mackerel is highly recommendable cook/chill system. Considering the DHSS standards for storage, the ideal shelf-life recommended for Broiled Spanish Mackerel is within 4 days excluding cooking day. For Broiled Spanish Mackerel, critical control points were purchasing and receiving of frozen Spanish Mackerel, heating, chilling, chilled storage, reheating and distribution.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.291-297
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• 2000

This study was conducted to find out the environmental factors affecting the differences in the half-life of the insecticide cyfluthrin in soil between field and laboratory tests carried out in 1998. Degradation and leaching of cyfluthrin in soil were examined under various environmental conditions that were considered to affect the residuality. Cyfluthrin was degraded 1.9 times faster in non-sterilized soil than in sterilized soil and 1.2 times at $25^{\circ}C$ than at $15^{\circ}C$. The half-lives of cyfluthrin were 61.4 days under the dark condition and 4.5 days under sunlight, and those were 11.8 days under the open condition and 23.8 days under the closed condition. The half-lives of the authentic compound and the commercial product of cyfluthrin were 15 and 1 day in the field test and 26 and 3 days in the laboratory test, respectively. Cyfluthrin was rapidly degraded with an increase in soil moisture content and decomposed faster in the alkaline solution of pH 12 than in the acidic solution of pH 3, but the half-life of cyfluthrin did not make any difference between pH 6.4 of the field test soil and pH 5.6 of the laboratory test soil. Cyfluthrin was immobile in soil from the results that $81{\sim}94%$ of the initial amount remained in the $0{\sim}2\;cm$ layer of the soil column regardless of the amount and time of rainfall after the chemical treatments. From viewing the abovementioned results, soil moisture content, sunlight and formulation type affected greatly soil microbes and volatilization affected slightly, and temperature, pH and rainfall did not affect the big difference in the half-life of cyfluthrin in soil between the field and laboratory tests in the year of 1998.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.19-30
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• 2000

LaF, KzFS1, LBO glass were manufactured successfully by using platinum crucible in LaF and using clay crucible in the KzFS1 and LBO. There was optically transparent and the refractive indexes were measured by minum deviation method of prism. LaF, KzFS1, LBO show that the refrective indexes are $n_d$ = 1.770 in LaF, $n_d$ = 1.603 in KzFS1, $n_d$ = 1.560 in LBO. The transmittance were obtained that LaF has 85%, and KzFS1 has 83% and LBO has 89% in visible range. These glasses have no any absorption spectrum under visible range. Therefore it has no any color.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.14 no.2
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• pp.79-87
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• 1978

This is an experimental study on friction welding and heat treatment of engine exhaust valve materials whose welding combination is SCr4 as stem to 21-4N as head and SUH3 to 21-4N. In this study, not only the experiments of friction welding under the selected optimum welding condition and the examination of the mechanical properties were carried out, but also the heat treatment of friction welded specimens under the two selected conditions was taken to obtain the better welding character, eliminating the latent stress and the hardness peak which appeared at the welded zones of heat resisting steel(21-4N, SUH3) and low alloyed steel ($SCr_4$) friction weldments. The results obtained by the experiments and consideration in this study are as follows: I) It was experimentally proved quite reasonable that 'speed=3,OOO rpm, heating pressure Pl=8 kg/ mm2, upsetting pressure p, = 20 kg/mm', heating time $t_1$ = 3 see, upsetting time TEX>$t_2$ = 2.5 sec' was selected as the optimum welding condition for friction-welding the engine exhaust valve materials $SCr_4$ to 21-4 Nand SUH 3 to 21-4 N. 2) The results of the previous study and this one on friction welding of such dissimilar materials as SUH 3-SUH 31, SCr 4-SUH 31, SCr 4-SUH 3, SUH 3-CRK 22, SCr4-21-4 Nand SUH3-21-4 N agreed with each other substantially in the friction welding characteristics at welded interface zones. 3) It was also certified quite satisfactory that '600\ulcornerCX30 min. Xroom air cooling' as an optimum heat treatment condition of the friction welded materials SCr 4-21-4 Nand SUH 3-21-4 N was experimentally determined to eliminate the latent stress and the hardness peak at welded zones. 4) About 20% of the tensile strength before heat treatment of friction welded specimens was decreased after heat treatment 600\ulcornerCX30 min. Xair cooling, but the location of fracture was moved from heat affected zone to parent $SCr_4$ & SUH3. 5) Microscopic examination of the weld joints friction-welded and heat-treated under the above mentioned conditions revealed that the weld zone is very narrow and has a fine grained intermixed structure without any welding defects. 6) The above mentioned conditions can be also utilized as friction welding parameters of the other dissimiar materials for engine valve production.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.144-150
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• 2002

Sweet persimmon were tested in order to identify their use as secondary material which is excellent in function and taste as food. Samples were soaked for 1 and 5 min with NaCl concentration(0, 1 and 3%) at a certain heating temperature(25, 75 and 95$\^{C}$), and then tannin, vitamin C, flavonol, color intensity, sensory test and textural properties were analysed. The results of the analyses were as follows. Tannins were decreased as heating temperature, NaCl concentration and soaking time were increased, especially, that the control was 420 mg% but decreased 228 and 198 mg% at 95$\^{C}$(1 and 3% NaCl concentration) for 5 min. soaked in each. Vitamin C content also decreased more in higher temperature and NaCl concentration than control(122.4 mg%). Color intensity showed higher value in 1. and b than in heating temperature, NaCl concentration and soaked time longer remarkably, but a value decreased. The peel of sweet persimmons was analyzed myricetin(2.0 $\mu$g/g), quercetin(34.5 $\mu$g/g) and kaemperol(1.1$\mu$g/g), but in pre-treatment sample(95$\^{C}$, 1% NaCl concentration and 5 min. soaked) was showed higher myricetin(9.5 $\mu$g/g) and quercetin(5.5 $\mu$g/g). Textural properties were good in pre-treatment sample(95$\^{C}$, 1% NaCl concentration and 5 min. soaked) such as brittleness, cohesiveness, gumminess and chewiness. In sensory analysis, the pre-treatment samples(95$\^{C}$, 1% NaCl concentration and 5 min. soaked and 95$\^{C}$, 3% NaCl concentration and 1 min. soaked) were showed higher point than others.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.554-560
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• 1991

The physicochemical properties of Korean yam starches (D. aimadoimo, D. batatas and D. japonica) were investigated. The mean granular size of starches were 23.5 μm for D. aimadoimo, 23.9 μm for D. batatas and 18.2 μm for D. japonica. Amylose content, blue value and water binding capacity was $29{\sim}33%,\;0.42{\sim}0.51%\;and\;109.9{\sim}118.3%$, respectively. The optical transmittance of 0.3% (dry basis) yam starch suspensions were increased at $70{\sim}75^{\circ}C$ and D. japonica showed typical two-step transmittance curve. The swelling power and solubility patterns increased over $60^{\circ}C$, and D. aimadoimo was the highest values. Amylogram patterns of 5% (dry basis) yam starch suspensions, determined by Brabender amylograph, were similar to that of yam flours and the viscosity of D. aimadoimo had 630 BU, which was about 5 times higher than 130 BU for D. batatas and D. japonica. Observation under scanning electron microscope lefted marks of resistance to glucoamylase because these surfaces were similar to the natural granules. In rates of solubiliazation by dimethyl sulfoxide, D. aimadoimo showed the highest value. (3-Amylolysis limits of yam starches and their amylose were $71.8%{\sim}75.5%\;and\;90.2{\sim}92.1%$, respectively. Gel filtration patterns of debranched amylopectin by pullulanase were divided into 3 peaks. The weight ratios of peak III to peak II in yam starches were $2.15%{\sim}2.42%$.