• Korean Journal of Food Science and Technology
• /
• v.37 no.3
• /
• pp.352-359
• /
• 2005

Uncertainty involved during determination of vitamin C content in infant formula was quantified by indophenol titration method. Uncertainty sources in measurand, such as purity, weight, final volume of standard, volume of standard solution used for titration, sample weight, final volume of sample, extraction solution used for titration, titration of extraction solution and standard solution by indophenol solution were identified and used as parameters for combined standard uncertainty based on Guide to the expression of uncertainty in measurement (GUM) and Draft EURACHEM/CITAC Guide. Uncertainty parameters of each source in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, repeatability, reproducibility, end point of titration, 1 mL pipet, 5 mL autopipet, and 100 mL mass flask. Each uncertainty component was evaluated by types A and B and included to calculate combined uncertainty. Analytical test result for traceability under laboratorial conditions using Certified Reference Material (CRM) test was certified as $108.4{\pm}1.7mg/100g$, which was within CRM certification range of $114.6{\pm}6.6mg/100g$. Uncertainty test result of vitamin C content of 5 g sampling was $56.7{\pm}2.44mg/100g$. Uncertainty could be reduced by identification of uncertainty sources and components related with vitamin C determination by indophenol titration method and by decreasing uncertainty sources and components.

• Korean Journal of Ichthyology
• /
• v.1 no.1_2
• /
• pp.9-18
• /
• 1989

Blenniid fish, Istiblennius stellifer(jordan et Snyder) is distributed in the coastal waters of south-eastern Korea and Japan. Matured adults of blenniid fish were collected from the rocky shore of Namchun-dong, Nam-gu, Pusan, Korea on May 15, 1988. The fertilized eggs were incubated and the larvae were reared in laboratory. The eggs of this species were demersal and adhesive, and their diameters varied from 0.84 to 0.88 mm(mean 0.86 mm, n=30). They have a number of small oil globules. The water temperature throughout incubation ranged from 18.5 to $23.3^{\circ}C$ and salinity was maintained at $28.2-29.5\;^{\circ}/_{\circ\circ}$. The hatching took place in 130 hours after fertilization. The newly hatched larvae were 2.70 mm in total length with 11 (abdominal)+22~25 (caudal)=33-36 myomeres. The larvae absorbed the yolk material and oil globule completely in 10 days after hatching and became postlarvae. Total lengths of the larvae reached 4.65 and 5.75 mm in 10 and 13 days after the hatching, respectively.

• Clean Technology
• /
• v.17 no.1
• /
• pp.62-68
• /
• 2011

Hydrodynamic characteristics in multistage annular type fluidized bed (riser: $0.01{\times}0.025{\times}2.8m^3$, J-valve: $0.009{\times}0.015m^2$)were investigated. Glass beads ($d_p=101{\mu}m$, ${\rho}_b=1,590kg/m^3$, $U_{mf}=1.25{\times}10^{-2}m/s$, Geldart classification B) was used as a bed material. Accumulated weight by the electronic balance was measured to determine the solid flow rate in batch-type. In circulation condition, we measured the accumulated weight of particle transported from riser. At the steady state condition, solid circulation rate was calculated from time interval of the heated bed material passing between two thermocouples. Solid flow rate increased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 2.2 to 23.4 kg/s. However, mean residence time decreased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 1,438 to 440 s. The solid holdup in the riser was determined by measuring pressure differences according to the riser height. These results showed a similar trend to that of simple exponential decay type except for the top section of the riser. To verify the gas bypassing from top bubbling beds to middle bubbling beds, $CO_2$ gas was injected by tracer gas in constant ratio, and then was measured $CO_2$ concentration in outlet gas by gas chromatography. Gas bypassing occurred below 2.6% which is negligible value.

• Clinical and Experimental Pediatrics
• /
• v.46 no.12
• /
• pp.1235-1241
• /
• 2003

Purpose : We assessed the dynamic characteristics of 16 nebulizer/compressor combinations currently available in Korea. Methods : The 16 nebulizer/compressor combinations(Pariboy Type 38/Long life, Pariboy Type N/Long life, Pariboy Type N/Salter 8900, Pariboy Type N/LC, Devilbiss pulmoaid-LT/Hudson, Devilbiss pulmoaid/Hudson, Mesmed neb-300/Own, San-up 3040/Hudson, Midas(Basic)/Own, AirJolie 2/Hudson, Thomas 1127/Salter 8900, Noel NE-2000/Salter 8900, Omron CX3/Hudson, Chang Woo CWN-100/Salter 8900, Voyage/Mefar, Chang Woo ASI-Pro/Medel jet pulse) were evaluated in terms of particle size and mass output. In addition, we determined the effects of nebulizer fill volume on mass output. Results : Pariboy Type N/Long life has the highest respirable mass of 0.184 mg/min and Mesmed Neb-300/Own has the lowest 0.019 mg/min. Pariboy Type N/Long life has the highest mass output of 0.68 mg/min and the shortest mass median aerodynamic diameter(MMAD) of $3.76{\mu}m$. All combinations other than Pariboy Type N/Long life produced a MMAD of over $5{\mu}m$. MMAD over a 5 min nebulization ranged 3.76 to $9.83{\mu}m$. There were no significant effects of fill volume on mass output. Conclusion : We concluded that there is a wide variation in performance of nebulizer/compressor combinations. The characteristics of nebulizer/compressor combinations should be considered in selecting products.

• Publications of The Korean Astronomical Society
• /
• v.34 no.3
• /
• pp.31-40
• /
• 2019

We study the internal structure under the artificial mountain of Heumkyeonggak-nu, a Korean water-powered clock in the early Joseon dynasty. All the puppets on the artificial mountain are driven by the rotational force generated by the water wheel at their designated time. We design a model that work with three parts of the artificial mountain. At the upper part of the artificial mountain to the east, west, north and south, there are four puppets called the Four Mystical Animal Divinity and four ladies called the Jade Lady respectively. The former rotates a quarter every double hour and the latter rings the bell every hour. In the middle part of this mountain is the timekeeping platform with four puppets; the Timekeeping Official (Hour Jack), the Bell-, Drum-, and Gong-Warriors. The Hour Jack controls time with three warriors each hitting his own bell, drum, and gong, respectively. In the plain there are 12 Jade Lady puppets (the lower ladies) combined with 12 Oriental Animal Deity puppets. In his own time a lady doll pops out of the hole and her animal doll gets up. Two hours later, the animal deity lies down and his lady hides in the artificial plain. These puppets are regularly moved by the signal such as iron balls, bumps, levers, and so on. We can use balls and bumps to explain the concept of the Jujeon system. Iron balls were used to manipulate puppets of the timekeeping mechanism in Borugak-nu, another Korean water-powered clock in Joseon dynasty, which was developed earlier than Heumgyeonggak-nu. According to the North Korea's previous study (Choi, 1974), it is obvious that bumps were used in the internal structure of Heumgyeonggak-nu. In 1669, The armillary clock made by Song, I-young was also utilized bumps. Finally we presented mock-ups of three timekeeping systems.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.17 no.2
• /
• pp.59-66
• /
• 2013

Purpose: Recently, there is an increase of the number of hospitals using auto dispenser to reduce occupational radiation exposure when drawing up of the $^{18}F-FDG$ dose (5.18 MBq/kg) in a syringe from the dramatic high activity of $^{18}F-FDG$ multidose vial. The aim of this study is to confirm that using auto dispenser actually reduces the radiation exposure for technologists. Also we analyzed the reproducibility of auto dispenser to find optimized dispensing method for the device. Materials and Methods: We conducted three experiments. Comparison of radiation exposure on chest and hands: The chest and hands exposure dose received by technologists during the injection were measured by electronic personal dosimeter (EPD) and ring TLD respectively. Reproducibility of dispensed volume: We draw up the normal saline into 5 and 2 mL syringe using auto dispenser by changing the volume from 1 to 15 mm for 5 times in the same setting of the volume. The weight of 5 normal saline dispensed from the device at same volume was measured using micro balance and calculated standard deviation and coefficient of variation. Reproducibility of dispensed radioactivity: We dispensed 362.6 $MBq{\pm}10%$ of $^{18}F-FDG$ in 5 and 2 mL syringes from the multidose vial of different specific activity. In the same setting of volume, we repeated dispensing for 4 times and compared standard deviation and coefficient of variation of radioactivity between 5 syringes. Results: There was significant difference in the average of chest exposure dose according to the dispensing methods (P<0.05). Also, when dispensing $^{18}F-FDG$ in manual method, exposure dose was 11.5 times higher in right hand and 4.8 times higher in left hand than in auto method. In the result of reproducibility of dispensed volume, standard deviation and coefficient of variation shows decline as the dispensing volume increases. As a result of reproducibility of dispensed radioactivity, standard deviation and coefficient of variation increases as the specific activity increases. Conclusion: We approved that the occupational radiation exposure dose of technologists were reduced when dispensing $^{18}F-FDG$ using auto dose dispenser. Secondly, using small syringes helps to increase reproducibility of auto dose dispense. And also, if you lower the specific activity of $^{18}F-FDG$ in multidose vial below 915-1,020 MBq/mL, you can use auto dispenser more effectively keeping the coefficient of variation lower than 10%.

• Journal of Food Hygiene and Safety
• /
• v.26 no.2
• /
• pp.142-149
• /
• 2011

An isocratic high performance liquid chromatography (HPLC) method for routine analysis of deoxynivalenol in noodles was validated and estimated the measurement uncertainty. Noodles (dried noodle and ramyeon) were analyzed by HPLC-ultraviolet detection using immunoaffinity column for clean-up. The limits of detection (LOD) and quantification (LOQ) were 7.5 ${\mu}g$/kg and 18.8 ${\mu}g$/kg, respectively. The calibration curve showed a good linearity, with correlation coefficients $r^2$ of 0.9999 in the concentration range from 20 to 500 ${\mu}g$/kg. Recoveries and Repeatabilities expressed as coefficients of variation (CV) spiked with 200 and 500 ${\mu}g$/kg were $82{\pm}2.7%$ and $87{\pm}1.3%$% in dried noodle, and $97{\pm}1.6%$ and $91{\pm}12.0%$ in ramyeon, respectively. The uncertainty sources in measurement process were identified as sample weight, final volume, and sample concentration in extraction volume as well as components such as standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. Deoxynivalenol concentration and expanded uncertainty in two matrixes spiked with 200 ${\mu}g$/kg and 500 ${\mu}g$/kg were estimated to be $163.8{\pm}52.1$ and $435.2{\pm}91.6\;{\mu}g$/kg for dried noodle, and $194.3{\pm}33.0$ and $453.2{\pm}91.1\;{\mu}g$/kg for ramyeon using a coverage factor of two which gives a level of statistical confidence with approximately 95%. The most influential component among uncertainty sources was the recovery of matrix, followed by calibration curve.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.2
• /
• pp.169-178
• /
• 2011

BACKGROUND: This study aimed to estimate the measurement uncertainty associated with determination of cadmium and lead from tomato paste by ICP/MS. The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, molecular weight, working standard solution, calibration curve, recovery and repeatability) in associated with the analysis of cadmium and lead were evaluated. METHODS AND RESULTS: The guide to the expression of uncertainty was used for the GUM (Guide to the expression of Uncertainty in Measurement) and Draft EURACHEM/CITAC (EURACHEM: A network of organization for analytical chemistry in Europe/Co-Operation on International Traceability in Analytical Chemistry) Guide with mathematical calculation and statistical analysis. The uncertainty components were evaluated by either Type A or Type B methods and the combined standard uncertainty were calculated by statistical analysis using several factors. Expected uncertainty of cadmium and lead was $0.106{\pm}0.015$ mg/kg (k=2.09) and $0.302{\pm}0.029$ mg/kg (k=2.16), on basis of 95% confidence of Certified Reference Material (CRM) which was within certification range of $0.112{\pm}0.007$ mg/kg for cadmium (k=2.03) and $0.316{\pm}0.021$ mg/kg for lead (k=2.01), respectively. CONCLUSION(s): The most influential components in the uncertainty of heavy metals analysis were confirmed as recovery, standard calibration curve and standard solution were identified as the most influential components causing uncertainty of heavy metal analysis. Therefore, more careful consideration is required in these steps to reduce uncertainty of heavy metals analysis in tomato paste.

• Korean journal of food and cookery science
• /
• v.6 no.3 s.12
• /
• pp.95-104
• /
• 1990

This survey was performed to investigate the actual holding conditions of the electric tools, gas tools and small cooking tools in the four Korean big cities; Seoul, Pusan, Kwangju and Taejon. The results were as follows; 1. Each family had more than 8 items on the average, of 24 kinds of electric tools under investigation. The holding ratio of refrigerators was the highest (99.6%), and that of dish washers was the lowest (3.4%). 2. The holding ratio of gas-ranges was the highest(92.2%) and that of gas-ovens was the lowest (2.2%) of 4 kinds of gas tools under investigation. 3. Each family had more than 45 items on the average, of 86 kinds of small cooking tools under investigation. The holdings ratios of openers and wicker baskets were very high (98.2% and 96.6%, respectively), and those of noodle tools and Shinsonros were very low (13.8% and 13.6%, respectively). 4. The holding ratios of various kinds of cooking tools had interrelations with the size of city, housewife's educational background, family income, house style, private residence, etc.

• Korean journal of food and cookery science
• /
• v.9 no.1
• /
• pp.7-13
• /
• 1993

This survey was performed to investigate the holding amount of the various kinds of cooking tools of the farm and fishing villages in Chungnam area. The results were as follows: 1. The holding ratio of refrigerators was the highest (97.9%), and that of toasters was the lowest (1.9%) among the electric tools. 2. The holding ratio of gas-ranges was the highest (95.7%) and that of gas oven-ranges was the lowest (1.2%) among 4 kinds of gas tools under investigation. 3. The holding amount of pans was the highest among the cooking tools and that of wicker baskets was very high among the small cooking tools. The holding ratios of egg-cutters and lemon-squeezers were very low (4.1% and 2.9%, respectively). 4. The holding ratios of various kinds of cooking tools were related to the housewife's educational background and family income.