• Journal of Radiation Industry
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• v.4 no.1
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• pp.39-45
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• 2010

The pollution of antibiotics is a major cause of spreading antibiotics resistant bacteria in the environment. Applications of ozonation, UV, and ${\gamma}-ray$ irradiations have been introduced to remove antibiotics in the effluents from wastewater treatment system. In this study, we compared the chemical (HPLC) and biological (antimicrobial susceptibility test, AMS) assays in measuring of the concentrations of residual antibiotics after ${\gamma}-ray$ and UV irradiation. Most samples were degraded by ${\gamma}-ray$ irradiation (1~2 kGy). However, lincomycin and tetracycline were not degraded by UV irradiation. The concentration of residual antibiotics, that was treated with ${\gamma}-ray$ and UV irradiation, measuring by bioassay was similar to HPLC. The concentrations of ${\gamma}-ray$ irradiated cephradine measured by AMS test were 2 times higher than that of HPLC assay, indicating AMS test is more sensitive than HPLC assay. These results indicate that ${\gamma}-ray$ irradiation technique is more useful than UV irradiation, and biological assay is more useful to detect the antibiotics and toxic intermediates in antibiotics degradation.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.781-790
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• 2012

The HyperGam program was developed for the analysis of complex HPGe ${\gamma}$-ray spectra. The previous version of HyperGam was mainly limited to the analysis of ${\gamma}$-ray peaks and the manual logging of the result. In this study, it is specifically developed into a tool for the isotopic analysis of spectra. The newly developed features include nuclide identification and activity determination. An algorithm for nuclide identification was developed to identify the peaks in the spectrum by considering the yield, efficiency, energy and peak area for the ${\gamma}$-ray lines emitted from the radionuclide. The detailed performance of nuclide identification and activity determination was accessed using the IAEA 2002 set of test spectra. By analyzing the test spectra, the numbers of radionuclides identified truly (true hit), falsely (false hit) or missed (misses) were counted and compared with the results from the IAEA 2002 tests. The determined activities of the radionuclides were also compared for four test spectra of several samples. The result of the performance test is promising in comparison with those of the well-known software packages for ${\gamma}$-ray spectrum analysis.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.103-111
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• 1996

This paper provides a test of the composite hypothesis that a random sample is (two parameter) gamma distributed when both the scale and shape parameters are estimated from the data. The test statistic is a variant of the usual Anderson-Darling statistic, the primary difference being that the statistic is based on the maximum likelihood estimator of the shape parameter of the assumed gamma distribution. The percentage points are developed via simulation and are presented graphically. Examples are provided.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.85-87
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• 1964

In order to stabilze alloxan as a reagent for detection of amino acids by spot test, sugars and other reductants were added to the aqueous alloxan solution. It was found that lactose was the best for the purpose. The alloxan reagent containing lactose did not give color change on blank test and was very stable that there was no color change even it was allowed to stand in room temperature for several months. The color reaction with amino acids and some amines was not affected by lactose. This spot test for amino acids is in sensitivity as comparable to that of the previously reported methods and gave color reaction with proline and hydroxyproline to 1${\gamma}$ and 5${\gamma}$ respectively.

• Journal of Korean Society for Quality Management
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• v.43 no.2
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• pp.169-184
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• 2015

Purpose: This paper is concerned with optimally designing accelerated degradation test (ADT) plans based on a gamma process for the degradation model. Methods: By minimizing the asymptotic variance of the MLE of the q-th quantile of the lifetime distribution at the use condition, the test stress levels and the proportion of test units allocated to each stress level are optimally determined. Results: The optimal plans of ADT are developed for various combination of parameters. In addition, a method for determining the sample size is developed, and sensitivity analysis procedures are illustrated with an example. Conclusion: It is important to optimally design ADT based on a gamma process under the condition that a degradation process should be always nonnegative and strictly increasing over time.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.217-227
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• 1997

These experiments were performed to investigate the safety of the three medicinal herbs- Curcuma longa Linne, Paeonia japonica Miyabe, Scutellaria baikalensis George-irradiated with gamma rays in respect of genotoxicity. The methanol-soluble and water-soluble fractions of the methanol-water extracts of the 10 kGy gamma-irradiated herbs were examined in two short-term in vitro tests : (1) Salmonella typhimurium reversion assay (Ames test) in strain TA 98, TA 100 and TA 012 (2) Micronucleus test in cultured Chinese hamster ovary (CHO) cells. No mutagenicity was detected in the assays with or without metabolic activation. From these results, the safety of the herbs irradiated with gamma rays at practical doses could be revealed in further tests of genotoxicity in vivo, chronic and reproductive toxiceity.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.137-142
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• 2005

The genotoxicological safety of fermented vegetables pasteurized by gamma irradiation was examined to consider the possibility of the application of irradiation for extending of fermented vegetables. A fermented vegetable was irradiated at 20 kGy to assure its toxicological safety even at a high dose of radiation. The Ames test with Salmonella typhimurium (TA98, TA100, TA1535, TA1537) and Escherchia coli (WP2), and the chromosomal aberration test in Chinese hamster lung (CHL) cells were performed. In vivo micronucleus test were conducted in mouse bone marrow cells. With or without metabolic activation, negative results were obtained in the Ames test and the chromosomal aberration test. In the micronucleus test, there was no enhancement in the formation of micronucleus, and there were no such significant differences between the irradiated and non-irradiated samples. The observed results indicated that, a level of 20 kGy of gamma irradiation on the fermented vegetable did not bring about any genotoxic effects under the described experimental conditions.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.07a
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• pp.25-37
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• 2002

The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

• Economic and Environmental Geology
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• v.9 no.3
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• pp.135-141
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• 1976

The gamma-gamma logging method appplying in geophysical research are presented in this paper_ The logging probe assembly was designed which permits changing the source-to-detector spacing while conditions of proceeding ${\gamma}-{\gamma}$ logging, which a collimated gamma ray source ($^{60}Co$, 0.5mCi and/or 2 mCi) is separated from the scintillation detector as shown in Fig. 2 and 3, size is 6.0 cm in diameter and 120.0 cm in long and the exposed parts are made of stainless steel pipe. The results is confirmed by the experiment performed mainly in granite rock where a slightly constant shape was obtained but sometimes was shown sharpness shape for the measured scattered gamma-ray intensity. Consequently, the experimental results are obtained an adequate intensity of scattered gamma-rays and favourable response to density change, and also very closely correspond to between core samples of the test boring and to used this method of ${\gamma}-{\gamma}$ logging in the test bore-hole of the strata.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1192-1200
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• 2004

Gamma irradiations at 5 or 10 kGy were applied to salted and fermented anchovy sauce, for improving the hygiene Quality and evaluating the genotoxicological safety. In vitro genotoxicological safety of irradiated sauces was evaluated by Salmonella Typhimurium (TA98, TA100, TAI535 and TAI537) and E. coli WP2 uvrA, reversion assay, SOS chromotest (Escherichia coli PQ37), and chromosome aberration test (Chinese hamster lung fibroblast cells) in the absence or presence of an exogenous metabolizing system (S9 mix). The gamma-irradiated samples were not significantly different from nonirradiated-control for three in vitro tests (p＜0.05). ：In vivo micronucleus test using ICR mice (male) was not significantly different from the control at p＜0.05. The salted and fermented anchovy sauce exposed to 5 or 10 kGy-gamma ray revealed negative results in these three in vitro mutagenetic tests and in vivo micronucleus test upto 50,000 $\mu$g/plate, respectively. The results indicated that 5 or 10 kGy gamma-irradiated salted and fermented anchovy sauces did not show any mutagenicity.