• Journal of the Korean Chemical Society
• /
• v.11 no.1
• /
• pp.12-16
• /
• 1967

Fading of Chlorantine Fast Red 5B (C.I. Direct Red 81) on cotton fabric exposed to carbon are light was examined. It was observed that the dye had anomaly in CF curve slope, while normal in CFG one. Auther considered that the reason for discrepancy of the one with the other curve slope might be appeared from Weber-Fechner law, and derived following equation $F_v=[logC_0-log(C_0-C_0F_t/100)]{\times}100/(logC_0+b)$ where $F_t$; the proportion of dye faded after t hour exposure. $F_v$; the proportion of dye faded after t hour exposure, when a pattern is judged by visual method $C_0$; initial dye concentration. b; constant. also, the reason for increasing lightfastness with dye concentration was discussed on view of the above equation.

• Journal of Food Hygiene and Safety
• /
• v.34 no.6
• /
• pp.534-541
• /
• 2019

his study assessed microbial contamination of leeks and leek-cultivated soil. Leeks and leek-cultivated soil were collected in A and B regions and accounted for 39 and 33 samples, respectively. All of the samples were analyzed for the presence of sanitary indicator bacteria (total aerobic bacteria, coliforms and Escherichia coli), Salmonella spp., E. coli O157:H7, Listeria monocytogenes, and Bacillus cereus. In A and B region, the total aerobic bacteria was in the range of 5.87-8.78 log CFU/g for leeks and 5.94-8.45 log CFU/g for leek-cultivated soil. The coliform in leeks and leek-cultivated soil was in the range of 1.20-7.36 log CFU/g and 2.45-5.87 log CFU/g, respectively. B. cereus was detected from some of the samples while other pathogens were not detected. This study provides important background information on the microbiological safety of fresh vegetable cultivation environments.

• Journal of Food Hygiene and Safety
• /
• v.29 no.4
• /
• pp.253-259
• /
• 2014

This study was conducted to investigate survival of Bacillus cereus (B. cereus) on stainless steel and polyvinyl chloride (PVC) and its transfer from two material to lettuce. The stainless steel and PVC were innoculated with B. cereus and stored at 6 combination conditions (temperature : $20^{\circ}C$ and $30^{\circ}C$, relative humidity (RH) : 43%, 69%, and 100%). Although the total numbers of B. cereus at RH 43% and RH 69% were reduced by 3.53-4.00 log CFU/coupon within 24 h regardless of material type, the spore numbers of B. cereus was lasted at 3.0 log CFU/coupon. When two materials were stored at $30^{\circ}C$, RH 100%, the spore numbers of B. cereus was rapidly increased by 3.0 log CFU/coupon. In addition, the reduction rate of B. cereus was decreased in the presence of organic matter. Transfer rate of B. cereus from surface of stainless steel and PVC to lettuce was increased by 10 times in the presence of water on the lettuce surface. As a result of this study, the presence of B. cereus on produce contact surfaces can increase the risk of cross-contamination. Thus, it is important that the packing table and conveyer belt in post harvest facility should be properly washed and sanitized after working to prevent cross-contamination.

• Journal of Food Hygiene and Safety
• /
• v.32 no.1
• /
• pp.50-56
• /
• 2017

The purpose of this study was to investigate the microbiological contamination of water and drinking cups in springs and to estimate the toxin gene, enterotoxin production ability and antibiotic susceptibility of foodborne pathogens. Ten spring water and 34 drinking cups were tested. The average number of total aerobic bacteria and coliform bacteria in spring water were 1.8 log CFU/mL and 1.2 log CFU/mL, and in drinking cups were $4.7log\;CFU/100cm^2$ and $1.7log\;CFU/100cm^2$. Salmonella spp., Staphylococcus aureus, E. coli O157:H7, Listeria monocytogenes, Vibrio parahaemolyticus, Yersinia enterocolitica were not isolated from all of samples but Bacillus cereus was detected in 5 (14.7%) of 34 drinking cups. The nheA and entFM genes were major enterotoxin genes in B. cereus isolated from drinking cups. All of B. cereus tested in this study produce non-heamolytic enterotoxin but only 2 isolates possessed heamolysin BL enterotoxin producing ability. B. cereus was resistant to ${\beta}-lactam$ antibiotics. These results revealed that the sanitary conditions of drinking cups in spring should be improved promptly. The substitution carrying a personal drinking cup for the public drinking cups equipped in springs is suggested to prevent food-borne illness.

• Bulletin of the Korean Chemical Society
• /
• v.7 no.1
• /
• pp.29-35
• /
• 1986

An empirical formula for semiconductive metal oxides is proposed relating nonstoichiometric value x to a temperature or an oxygen partial pressure such that experimental data can be represented more accurately by the formula than by the well-known Arrhenius-type equation. The proposed empirical formula is log x = A + $B{\cdot}1000/T\;+\;C{\cdot}$exp$(-D{\cdot}1000/T)$ for a temperature dependence and $log\;{\times}\;=a\;+b{\cdot}log\;Po_2\;+\;c{\cdot}$exp$(-d{\cdot}log\;Po_2)$ for an oxygen partial pressure dependence. The A, B, C, D and a, b, c, d are parameters which are evaluated by means of a best-fitting method to experimental data. Subsequently, this empirical formula has been applied to the n-type metal oxides of $Zn_{1+x}O,\; Cd_{1+x}O,\;and\;PrO_{1.8003-x}$, and the p-type metal oxides of $CoO_{1+x},\; FeO_{1+x},\;and\;Cu_2O_{1+x}$. It gives a very good agreement with the experimental data through the best-fitted parameters within 6% of relative error. It is also possible to explain approximately qualitative characters of the parameters A, B, C, D and a, b, c, d from theoretical bases.

• Fisheries and Aquatic Sciences
• /
• v.19 no.2
• /
• pp.8.1-8.11
• /
• 2016

To quantitatively estimate the influence of cuttlebone on the target strength (TS) of golden cuttlefish, the cuttlebone was carefully extracted from 19 live cuttlefish caught using traps in the inshore waters around Geojedo, Korea, in early May 2010 and the TS was measured using split-beam echosounders (Simrad ES60 and EY500). The TS-length relationships for the cuttlefish (before the extraction of cuttlebone, Fish Aquat Sci. 17:361-7, 2014) and the corresponding cuttlebone were compared. The cuttlebone length ($L_b$) ranged from 151 to 195 mm (mean $L_b$ = 168.3 mm) and the mass ($W_b$) ranged from 29.3 to 53.2 g (mean $W_b$ = 38.8 g). The mean TS values at 70 and 120 kHz were -33.60 dB (std = 1.12 dB) and -32.24 dB (std = 1.87 dB), respectively. The mean TS values of cuttlebone were 0.19 dB and 0.04 dB lower than those of cuttlefish at 70 and 120 kHz, respectively. For 70 and 120 kHz combined, the mean TS value of cuttlebone was -32.87 dB, 0.11 dB lower than that of cuttlefish (-32.76 dB). On the other hand, the mean TS value of cuttlebone predicted by the regression ($TS_b$ = 24.86 $log_{10}$ $L_b$ - 4.86 $log_{10}$ ${\lambda}$ - 22.58, $r^2$ = 0.85, N = 38, P < 0.01) was -33.10 dB, 0.04 dB lower than that of cuttlefish predicted by the regression ($TS_c$ = 24.62 $log_{10}$ $L_c$ - 4.62 $log_{10}$ ${\lambda}$ - 22.64, $r^2$ = 0.85, N = 38, P < 0.01). That is, the contribution of cuttlebone to the cuttlefish TS determined by the measured results was slightly greater than that by the predicted results. These results suggest that cuttlebone is responsible for the TS of cuttlefish, and the contribution is estimated to be at least 99 % of the total echo strength.

• Korean Journal of Food Science and Technology
• /
• v.43 no.2
• /
• pp.243-248
• /
• 2011

The prevalence and distribution of hazardous microorganisms were investigated from the major perilla cultivation area at Milyang, Gyeongnam province, Korea. Aerobic plate count (APC) and coliform count of perilla leaves were 4.82 log CFU/g and 3.85 log CFU/g, respectively. E. coli, S. aureus and B. cereus were detected in 3.0% (4/114), 7.9% (9/114) and 46.5% (53/114) of examined perilla leaves. However, E. coli O157:H7, Salmonella spp, and L. monocytogenes were not detected. The distribution of hazardous microorganisms in perilla leaf cultivation environment were compared and the concentration of APC and coliform counts were more than 3.0 log CFU/(mL, g, $100cm^2$, hand) from most of the samples. S. aureus were detected from irrigation water, packing table, packing vinyl, hand, and clothes. Also, B. cereus was frequently detected from the examined samples. Especially, packing table and collection container were contaminated with maximum 5.5 log $CFU/100cm^2$ of B. cereus. Good Agricultural Practice (GAP) system should be introduced to farms to enhance the safety of perilla leaves.

• Explosives and Blasting
• /
• v.9 no.1
• /
• pp.3-13
• /
• 1991

The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.5
• /
• pp.311-315
• /
• 2001

In order to improve a soil test-based fertilization model for nitrogen, the Mitscherlich-Baule-Spillman equation modified by Bray and his coworkers was introduced and tested for its possibility of application. The coefficients $C_1$ and $C_2$ in the equation A were calculated by applying 10 pot experimental results done by the National Institute of Agricultural Sciences and Technology. Then, a regression(B) between C_1 and x, the fertilizer level was estimated. log(Ymax-Y) = logYmax-$C_1x-C_2b$ (A) where Ymax : maximum yield. Y : yield without or with a limited amount of fertilizer applied, x : application level of fertilizer, b : content of a nutrient in soil, $C_1$ and $C_2$ : coefficients of x and b, respectively. log(0.05)=$-C_1x-C_2b$ (B) Fertilizer requirement calculated by the equation B was significantly correlated with the real level of fertilizer applied for 95 percentage of the maximum yield. A more extensive and precise study on $C_1$ and $C_2$ in the equation A in expected to improve significantly the fitness of soil analysis to the fertilizer recommendation.

• Korean Journal of Food Science and Technology
• /
• v.41 no.3
• /
• pp.334-338
• /
• 2009

To determine the contamination status of Sushi fish and rice, seventy-nine samples of Sushi were collected from wholesale markets and Japanese restaurants within the Seoul area and subsequently analyzed for food-borne pathogens. Total aerobic counts ranged from 4 to 6 log CFU/g for the sliced raw fish, and from 3 to 5 log CFU/g for the boiled rice. Higher levels of contamination were detected in bream and shrimp Sushi versus other types. Coliform counts of 3-4 log CFU/g were detected in the sliced raw fish, whereas levels in the boiled rice were one log CFU/g lower compared to the raw fish. The raw Sushi fish had higher amounts of contamination than the boiled rice, however, E.coli was not detected. The prevalence rates of pathogens, namely Staphylococcus aureus and Bacillus cereus, in the raw fish were 17% and 10%, respectively. Similarly, the prevalence rates in the boiled rice were 11% and 8% for S. aureus and B.cereus, respectively. Salmonella and Listeria monocytogenes were also detected; however, other pathogens such as Vibrio parahaemolyticus, Clostridium perfrigens, and Yersinia enterocolitica were not detected. Among the high contaminating pathogens, B.cereus was found in 13% of samples from the wholesale markets, while S.aureus was found in 30% of samples from the Japanese restaurants. Therefore, these data suggest that the primary microbial hazard factors for Sushi are S. aureus and B. cereus, in addition to V. parahaemolyticus, and further risk assessments should focus on those pathogens.