• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.65-78
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• 1990

For the purpose of Improving the sounding boards for the conventional GAYAKUM, I was making approximately 202 specimens of radial board, 371 specimens of tangential board by cutting along the grain and the part of stem and 31 specimens of the disjointed traditional GAYAKUM made in Paulownia coreana. And it was conducted to measure specific gravity, dynamic Young's modulus, internal friction, resonant frequency, velosity of sound and width of annual ring by the method of the frexural vibration in a free-free bar in the audio frequency range. And it confirmed the juvenile wood by measuring wood fiber length of specimens. It was also conducted to investigate dynamic properties and moisture absorption by various heat-treatment and to test dynamic Young's modulus and internal friction for the disjointed conventional GAYAKUM. The results obtained were summarized as follow: 1. The Juvenile wood is located within about 7 annual rings from the pith in Paulownia coreana. 2. As increased with the specific gravity, the dynamic Young's modulus had more and more increased, but the internal friction had slightly decreased. 3. I think that radial board would be good for sounding board wood. because radial board is higher than tangential board in dynamic Young's mudulus and internal friction is lower than tangential board. 4. The value of mean dynamic Young's modulus on the conventional GAYAKUM, radial board and tangential board of 604 samples is $0.4283\pm0.037(\times10^{11}dyne/cm^2)$, $0.4316\pm(\times10^{11}dyne/cm^2)$ and $0.4234\pm0.112(\times10^{11}dyne/cm^2)$ respectively. The value of the radial board showed little higher than that of conventional GAYAKUM, but It had a similar tendency between conventional GAYAKUM and tangential board. 5. The annual ring width by four aspect is more narrow in north and west than that of others. 6. The values of specific gravity and dynamic Young's modulus in the mature wood showed higher than those of juvenile wood. 7. As the grain angle in the butt wood more increased to bark from pith, the dynamic Young's modulus were low. Then it was not good for sounding board. 8. It appeared that the heat-treatment for sounding board wood had a more effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature. 9. As increased with the temperature, the rate of moisture absorption of heat-treatment wood had decreased. In conclusion, I thought that the sounding board wood for GAYAKUM would had the most effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature using the radial board of mature wood.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.535-543
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• 2013

The objective of this study was to analyse the residual stress in Larix kaempferi board during and after kiln-drying. The boards were primarily intended for using as laminar of cross laminated timber (CLT). In this study, the equivalence of moisture content by equalizing treatment was proved and reduction of residual stress by conditioning treatment was quantified. Prong test and slice test were carried out to analyse the residual stress in wood during drying. Transverse casehardening was measured immediately after making prong sample. Residual stress of four parts in wood from surface to center was analyzed quantitatively based on elastic deformation after just cutting slices from board. Tensile stress and compressive stress on the surface of board during drying did not exceed 2.2 MPa when boards were dried by kiln-drying schedule of T10-C4 and T12-D5. Because the tensile strength and compressive strength of transverse direction of Larix kaempferi lumber are 2.65 MPa and 4.60 MPa, application of more severe drying schedule can be recommended. Cup and twist were reduced by about 40% by equalizing and conditioning treatments after drying.

• Journal of the Korean Dietetic Association
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• v.19 no.3
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• pp.236-252
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• 2013

The purpose of this study was to assess the microbiological quality of home-delivered meals during production and delivery for children from low-income families. Production flows from a facility in Seoul that provides home-delivered meals were analyzed and the time-temperature of the food was measured. Microbiological assessment was performed for the production environment, personal hygiene, and food samples at each production and delivery step based on the process approach. It took 2 hours or longer from completion of production to meal delivery. An aerobic colony count (ACC) and coliform were not detected at knives, cutting boards, and dish towels. However, ACC (at pre-preparation, preparation, and packing areas) and coliform (at the preparation area) were detected on the hands and gloves of employees. Air-borne bacterial counts varied according to day and preparation area (ND~6 CFU/plate/15 min). Food temperatures, on the completion of production and meal delivery, fell into temperature danger zones. ACC and coliform counts of raw ingredients did not decrease after pre-preparation (washing and sanitizing) for menus involving food preparation with no cook step. ACC decreased after cooking step for menus of food preparation with cook step, but the ACC of the stir-fried and seasoned dried filefish fillet on the completion of cooking was too numerous to count due to improper heating. The ACC of seasoned young Chinese cabbages (a menu with complex food preparation) increased during delivery (from 2.5 log CFU/ml to 5.0 log CFU/ml). This qualitative assessment of foodborne pathogens revealed that B. cereus was detected in vegetable and meat product menus. These results suggest time-temperature control is necessary during production and delivery and management guidelines during production of home-delivered meals are provided for safe production.

• Korean journal of food and cookery science
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• v.30 no.1
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• pp.51-63
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• 2014

A microbiological quality evaluation on cooked food, food materials and cooking equipment was conducted in 14 school food services in Changwon area, South Korea for Ojingeochaesomoochim (vegetable salad with blanched squid) which went through cooking process after heating treatment. Only 5 schools out of the 14 (35.7%) observed the sanitization criteria of the Korean School Meals Sanitization Management for raw vegetables (concentration of chlorine solution: 100ppm, immersion time of sanitizing: 5 min). The acceptance rates regarding the microbial standards for Korean school meals showed improvement before and after of sanitization: for onions 57.1% vs 71.4%; cucumber 42.9% vs. 78.6%. However, garlic showed adverse sanitizing effect as the acceptance rate went down from 42.9% to 35.7%. Blanched squid and red pepper paste was acceptable in all 14 schools (100%), while squid seasoned with red pepper powder was acceptable in only 42.9% of the schools. Microbial results for knives, cutting boards, mixing bowls were satisfactory, however 35.7% of sanitary gloves that were put on right before the seasoning showed poor sanitization, and this indicated high probability of cross-contamination from the gloves. We calculated that 57.1% of the cooked foods were in accordance with the microbial standards for Korean school meals. Therefore, it is strongly recommended to have verification process, especially on the effectiveness of sanitization of raw vegetables, in cooking foods through cooking process after heating treatment in HACCP system of school food service.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.191-199
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• 1993

This paper describes the results of a systematic study to determine the characteristics of particle generated from various types of asbestos containing material(ACM) and manmade fiber material(MMFM) during operations of cutting and grinding in laboratory and workplace. Tests were conducted with a specially designed glove box which allowed complete sampling of the generated asbestos fibers. Specificially, air measurements were made during ACM and MMFM installation in building. All personal air samples collected were identified by polarized light microscopy(PLM), X-ray diffraction(XRD) and scanning electron microscope with energy dispersive X-ray analysis(SEM/EDXA). Also, the samples were counted by phase contrast microscope(PCM) in order to compare the results with the permissible exposure standard for workplace. Results indicate that the characterisitcs of fibers found in the roofing sheet, the ceiling and the wall insulation boards were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of rock wool. The concentrations of airborne fibers from various building materials cut by a grinder for 5 minutes were in the ranges of 0.09 $\sim$ 1.71 fibers/cc(f/cc). The highest concentration(1.71f/cc) was found during grinding the wall insulation board which also contains rock wool. The airborne fiber concentrations generated by installing at workplace were ranged from 0.0009 to 0.029 f/cc. All asbestos fibers from the ceiling insulation board at workplace were less than 20$\mu$m in length and more than 20% of them had the average aspect ratio greater than 20. Therefore, for the purpose of decreasing asbestos and man-made fiber concentrations at the workplace, the ceiling and wall board should use strong binding material to increase the binding force with fiber. Also, the permissible exposure standard for workplace(2.0f/cc) in Korea should be constituted below the maximum avaiable concentration measured at glove box.

• Journal of the Korean Dietetic Association
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• v.17 no.2
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• pp.142-160
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• 2011

The purpose of this study was to investigate food sanitation status in elderly welfare facilities and assess the performance of food sanitation practices. Twenty elderly welfare facilities out of 85 located in Seoul with a capacity of fewer than 50 persons participated. The food sanitation status of worktable, kitchen utensils (knives, cutting boards, ladles, spoons), and tableware and bowls were examined by ATP bioluminescence. The results found that the ATP value of knife was the highest. Those of ladles appeared relatively higher than others. Meanwhile, the tableware and bowls, although washed everyday after meals, had the lowest ATP value. This study also conducted a survey on the food sanitation practices of 32 cooking employees in the 20 facilities. Fifty-six percent were in their 40s, and 53% had graduated from high school. More than half (66%) of them had no certification of cooking. Half of the respondents had worked for at least 5 years in food service facilities, and had received food sanitation training. Among them, 31% said they applied food sanitation training while working, and 47% responded the training was very helpful. The foodservice employees demonstrated good food sanitation practices. The results show that food sanitation performance of the workers significantly differed according to their age, education level, total work experience in food service facilities, chef certification, and prior food sanitation experience.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.249-260
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• 1995

6 Central commissary and 2 conventional school foodservice operations were assessed in terms of time-temperature relationship and microbiological quality, and monitoring control methods were identified through hazard analysis during the phases of prodution and distribution. 2 conventional schools from Seoul and 6 commissary schools from Kyungkido were participated in the survey. Meals produced in central commissary were distributed to satellites, therefore delivery practices of foods were identified as critical. Microbiological test results for commissary and conventional schools revealed that microbiological quality of foods was mainly related to time-temperature management, types of food, and equipment sanitation not to the foodservice system used. Time-temperature profiles at temperature danger zone (7.2-60$^{\circ}C$) observed were to be related to the following sanitary practices: cooked vegetables were held at temperature danger zone for relatively longer delayed time (15-38$^{\circ}C$: 15-226 min, 7-60$^{\circ}C$: 75-226 min), and same results were observed for deep-fat fried cutlets (15-38$^{\circ}C$: 15-151 min, 7-60$^{\circ}C$: 33-151 min). Menu items with various ingredients and frequent contacts with hands and equipments during the production flow were held at temperature danger zone for longer delaying time than other menu items with brief prodution stages. Based on hazard analysis critical control points, microbiological quality was collectively affected by time-temperature relationships, equipment sanitation, proper cooking methods, and sanitary management competencies of dietitians. Microbiological test results of working equipments and surface of dishes and trays showed that immediate action should be taken. Cutting boards used in central kitchen were also showed similar results of potential dager of cross-contamination. Effective sanitary control methods were urgently needed.

• Journal of the Korean Dietetic Association
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• v.17 no.3
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• pp.287-301
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• 2011

This study examined the current status of foodservice management in elderly welfare facilities and evaluated food service workers' food safety practices and knowledge. For this, the directors of 20 elderly welfare facilities (each with fewer than 50 residents) located in Seoul were interviewed and a survey of 40 foodservice workers was conducted to determine their food safety knowledge and practices. The facilities accommodated an average of 28 residents. All the facilities were self-operated and approximately 62% were dependent on payments by residents. Only 15% had a dietitian in charge of menu planning, food purchasing, and food safety management. Approximately 50% had their facility managers take responsibilities for menu planning and food safety management. Most of the facilities provided food safety training within their own facility and sanitized their utensils, cutting boards, and dishcloths on a daily basis. A limited number of foodservice workers, insufficient training programs, and budget constraints were some of the major barriers to food safety management. Their average score on food safety practices was 1.62, and that on food safety knowledge was 17.6 out of 19 points. These results indicate that the foodservice workers had good food safety knowledge and appropriate food safety practices. There was a significant correlation only between food safety practices related to receiving and storing food products and knowledge of personal hygiene.

• Food Engineering Progress
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• v.14 no.4
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• pp.316-321
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• 2010

The efficacy of the ozonated water (0.1, 0.2, 0.4, 0.6, and 1.0 ppm) in reducing the risk of food-borne disease was investigated in this study. After inoculation of Listeria monocytogenes (ATCC 19112), Salmonella enterica subsp. enterica biovar Typhimurium (ATCC 12598), Escherichia coli O157:H7 (ATCC 43890) to lettuce, spinach, and beef, inhibition effect with different washing concentrations, time, and methods with ozonated and tap water were evaluated. As a result, there were 2.16 to 3.85 log CFU/mL reduction in different foods and 7 log CFU/mL reduction on cutting boards after watering with ozonated water. Higher than 0.2 ppm of ozonated water treatment reduced the growth of food-borne disease bacteria with increasing washing time and ozone concentration. These results suggested that the ozonated water treatment effectively improved the microbiological quality and food safety.

• Journal of Conservation Science
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• v.36 no.6
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• pp.483-493
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• 2020

In this paper, we present a nondestructive analysis using X-ray and microscopic investigation to detect the structure, manufacturing technique and preservation status of the Goryeo lacquered box Inlaid with Mother-of-pearl Chrysanthemum and Scroll Design (Goryeo Lacquered Box). We confirm that the Goryeo Lacquered Box consists of the soft wood as the basic material. The soft wood was coated with textile and then lacquered. The box structure of the Goryeo Lacquered Box was formed of wooden boards with wood plants added to the side, after processing into a trefoil-shaped. The wooden sides of the Goryeo Lacquered Box were cut at regular intervals for easier processing into a curved shape. Moter-of-pearl, tortoiseshell, and metal wire were used to decorate the surface. mother-of pearl was the cutting processing, and tortoiseshell was used for back coloring. The metal line was constructed using one line and twist line.