• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.411-417
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• 1994

For the analysis of fine ceramics, which is one of the new materials difficult to be dissolved, the methods of sample pretreatments such as alkali fusion and high pressure acid digestion were studied using inductively coupled plasma-atomic emission spectrometer(ICP-AES). For the Al2O3 powder sample, the results from high pressure acid digestion method showed better reproducibility than those obtained by alkali fusion technique. In the case of the analysis of SiC powder using the former method, impurities of the powder in the range of ppm were determined without matrix interference by removing Si as Si-F volatilization. Japan Certified Reference Materials (JCRM022 and JCRM023) were analyzed by this method for ultra fine powder and the results showed high accuracy and good reproducibility.

• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.53-63
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• 2010

The performance of two serial completely stirred tank reactors (CSTRs) for treatment of swine manure (SM) with Chinese cabbage silage (CCS) was studied. The two CSTRs of 41 liters each were connected in series and first reactor was fed swine manure with Chinese cabbage silage in 3:1 proportion by VS basis. The FOS/TAC, methane content (%) and pH were utilized as the parameters for the digester stability control. The FOS/TAC value was found to be effective indicator for instant digester condition. The stability of reactors can be obtained with the FOS/TAC value up to 1.0 with accumulation of FOS value below 10,000 mg/L. Material exchange method was effective in transferring the excess volatile fatty acids (VFA) from the first reactor to the second one and maintaining stability in both the reactors. The biogas yield and the methane yield was 0.55-0.61 and 0.41-0.42 L/g VS fed, respectively, at organic loading rate (OLR) of 2.2-2.6 g VS/L with total HRT of 32 days.

• Environmental Engineering Research
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• v.19 no.1
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• pp.59-66
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• 2014

The aim of this study was to assess the effect of pre-aeration on sludge solubilization and the behaviors of nitrogen, dissolved sulfide, sulfate, and siloxane. The results of this study showed that soluble chemical oxygen demand in sewage sludge could be increased through pre-aeration. The pre-aeration process resulted in a higher methane yield compared to the anaerobic condition (blank). The pre-aeration of sewage sludge, therefore, was shown to be an effective method for enhancing the digestibility of the sewage sludge. In addition, this result confirms that the pre-aeration of sewage sludge prior to its anaerobic digestion accelerates the growth of methanogenic bacteria. Removal rates for $NH_3$-N and T-N increased simultaneously during pre-aeration, indicating simultaneous nitrification and denitrification. The siloxane concentration in sewage sludge decreased by 40% after 96 hr of pre-aeration; in contrast, the sulfide concentration in sewage sludge did not change. Therefore, pre-aeration can be employed as an efficient treatment option to achieve higher methane yield and lower siloxane concentration in sewage sludge. In addition, reduction of nitrogen loading by pre-aeration can reduce operating costs to achieve better effluent water quality in wastewater treatment plant and benefit the anaerobic process by minimizing the toxic effect of ammonia.

• Journal of the Korean Society of Industry Convergence
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• v.15 no.3
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• pp.83-86
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• 2012

This study have cross checked the change of internal sludge-recycle in Full-scale Anaerobic-Digestion, and researched about not only the improvement of Bio-gas production from the digested sludge but also the efficient method of sludge minimization. Ultimate aim of the study is to reduce the amount of sludge by the improved efficiency of contact with the organic-matter and the microbes in Anaerobic-Digestion. The sludge-recycle fluidized sludge layer and raised the activity of the sludge, The sludge-recycle ratio of optimum was 500%, VS and COD removal ratio respectively appeared with 67.8% and 70.4%. Through these result of this study, it may be positive view to treat waste sludge by the sludge-recycle ratio in terms of minimization and circulation of resources.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.33-42
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• 2009

This study was performed to evaluate the hexavalent chromium content in flexography inks and organic pigments used as colorants for the ink. The digestion of sample was carried out under alkaline condition, and the content of soluble hexavalent chromium extracted from samples was determined by UV-visible colorimetric analysis method after alkaline digestion. Duplicate sampling system to obtain two digested samples, was applied in this study. To determine the hexavalent chromium content in the flexography ink and organic pigment colorimeteric analysis was employed. Because the organic pigment is the main ingredient of flexography ink it is important to remove the errors associated with the colorant of the ink in colorimetric determination. The duplicate sampling system allowed us to correct the errors associated with the colorimeteric measurement. The additional filtration was found an essential step to exclude colorimeteric error derived from the various precipitates. The soluble hexavalent chromium content in flexography inks was generally less than 5 ppm. Yellow, violet and some magenta colors showed higher soluble hexavalent chromium contents. The content of hexavalent chromium in organic pigments was greater than flexography inks, and yellow, violet and some magenta pigments contained greater amount of hexavalent chromium, which indicated that the hexavalent chromium in inks derives from the colorants. The soluble hexavalent chromium content in linerboards were below 1 ppm, and no hexavalent chromium was detected in UKP. Results suggested that flexography ink is the main factor to cause hexavalent chromium in linerboard and organic pigments.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.67-75
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• 2003

A total of 260 dogs were randomly selected from two different treed kennels that brucellosis has occurred (group 1, 126 dogs), and random selected breed kennel (group 2, 134 dogs), and monitored for Brucella canis (B. canis) by 2-mercaptoethanol rapid slide agglutination test (2ME-RSAT) and bacterial culture method. For the differentiation, PCR-RFLP using omp-31, wbkA and per genes used for 52 of B canis strains (strain I) isolated in this study and 3 of B. canis strains (strain II) isolated in 1994 in Korea. 2ME-RSAT revealed that 63/126 dogs (50.0%) and 12/134 dogs (9.0%) were positive in group I and group II, respectively. Bacterial culture revealed that 47/126 dogs (37.3%) and 5/134 dogs (3.7%) were positive in group I and group II, respectively. As the results of PCR-RFLP, $\underline{omp}-31$ was amplified from all Brucella spp, except B. abortus. All B. canis isolates showed unique PCR-RFLP pattern following digestion with Bmel8I. However, all Brucella spp. showed the same PCR-RFLP pattern following digestion with SalI. PCR-RFLP analysis of wbkA revealed that all Brucella spp. showed the same pattern following digestion with HindIII. PCR-RFLP analysis of per revealed that B. abortus 544 and B. melitensis 63/9 showed the same pattern, but different from B. suis and B. canis following digestion with HindIII.

• Preventive Nutrition and Food Science
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• v.22 no.2
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• pp.107-117
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• 2017

The purpose of this study was to evaluate the antioxidant and anticholinesterase activities of yellow and white bitter yams from South Western Nigeria using methanolic extraction and simulated gastrointestinal digestion models. The phenolic compounds in the bitter yam varieties were evaluated by high performance liquid chromatography with a diode array detector (HPLC-DAD). The total phenolic content of the bitter yams was measured by the Folin-Ciocalteu method, reductive potential by assessing the ability of the bitter yam to reduce $FeCl_3$ solution, and the antioxidant activities were determined by the 2,2-diphenyl-1-picrylhydrazyl radical ($DPPH^{\cdot}$) scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation ($ABTS^{{\cdot}+}$) scavenging activity, nitric oxide radical ($NO^{\cdot}$) scavenging ability, hydroxyl radical scavenging ability, and ability to inhibit $Fe^{2+}$-induced lipid oxidation. The HPLC-DAD analysis revealed the presence of some phenolic compounds in the studied bitter yam varieties, with varying degree of quantitative changes after cooking. The antioxidant indices (total phenolic content, total flavonoid content, reducing power, $DPPH^{\cdot}$ scavenging activity, $ABTS^{{\cdot}+}$ scavenging activity, and $NO^{\cdot}$ scavenging activity) were higher in the simulated gastrointestinal digestion model compared to the methanolic extract, with the in vitro digested cooked white bitter yam ranking higher. Similarly, the in vitro digested yams had a higher inhibitory action against lipid oxidation compared to the methanolic extracts, with the cooked white bitter yam ranking high. The methanolic extracts and in vitro enzyme digests showed no acetylcholinesterase inhibitory abilities, while methanolic extracts and the in vitro enzyme digest displayed some level of butyrylcholinesterase inhibitory activities. Therefore the studied bitter yams could be considered as possible health supplements.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.12
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• pp.1849-1857
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• 2007

The experiment was carried out using fistulated multiparous Holstein Friesian crossbred (75% Holstein Friesian and 25% Red Sindhi) dairy cows in their dry period fed on untreated rice straw to evaluate the nutritive value of local protein feed resources using the in sacco method and in vitro pepsin-pancreatin digestion. Experimental feeds were cottonseed meal (CSM); soybean meal (SBM); dried brewery's grains (DBG); palm kernel meal (PSM); cassava hay (CH); leucaena leaf meal (LLM). Each feedstuff was weighed into duplicate nylon bags and incubated in each of the two rumen fistulated cows for 0, 2, 4, 8, 16, 24, and 48 h. Rumen feed residues from bags of 16 h incubation were used for estimation of lower gut digestibility by the technique of in vitro pepsin-pancreatin digestion. Ruminal ammonia-nitrogen ($NH_3-N$) concentrations did not differ between treatments or time with a mean of 5.5 mg%. Effective degradability of DM of CSM, SBM, DBG, PSM, CH and LLM were 41.9, 56.1, 30.8, 47.0, 41.1 and 47.5%, respectively. Effective degradabilities of the CP in feedstuffs were 49.6, 59.2, 40.9, 33.5, 47.3 and 65.0% for the respective feedstuffs. The CP in vitro pepsin-pancreatin digestibility as ranked from the highest to the lowest were SBM, CSM, LLM, CH, DBG, PSM, respectively. The intestinal and total tract digestion of feedstuffs in the current study were relatively lower than that obtained from previous literature. The results of this study indicate that SBM and LLM were highly degradable in the rumen, while CH, CSM and DBG were less degradable and, hence resulted in higher rumen undegradable protein. Soybean meal and LLM could be used to improve rumen ecology whilst CH, CSM and DBG could be used as rumen by-pass protein for ruminant feeding in the tropics.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.58-64
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• 2014

Management of organic waste such as livestock manure has been considered as very important issue in terms of the environment. The anaerobic digestion of livestock manure become more attractive treatment method and has been widely applied. In this work, the properties of the residue after the anaerobic digestion of livestock manure was evaluated for providing the basic data to develop new application. The lignin and the ash contents of the residue were much higher than those of other biomass such as wood. The components of the residue were also analyzed with SEM-EDS and Elemental Analyzer. The addition of the residue into the handsheet paper resulted in the higher bulk and he higher air permeability with the loss of the strength properties. The water holding capacity of the handsheet were increased until the 40 % addition of the residue.

• The Journal of the Petrological Society of Korea
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• v.20 no.3
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• pp.161-172
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• 2011

Open beaker digestion method is routinely used as the sample preparation technique for trace element determination of rock samples by inductively coupled plasma mass spectrometry, With this method, however, dissolution of Zr and Hf is not always guaranteed especially when the samples contain refractory minerals. In this study, glass bead digestion technique was compared with conventional open beaker digestion technique for the sample preparation of three USGS rock standards such as AGV-2, BHVO-2, and G-3. Thirty trace elements including rare earth elements were analysed by ICP-MS and ICP-AES. There were no clear differences in analytical results for the AGV-2 and BHVO-2 standards between the two techniques, but Zr, Hf, Y, and middle- to heavy- rare earth element concentrations of the G-3 standard prepared by open beaker digestion technique were significantly lower than the recommended values. This can be attributed to the presence of refractory mineral zircon. On the contrary, all the analytical results of the G-3 standard prepared by glass bead digestion technique were in good agreement with the recommended values, indicating complete dissolution of zircon. The analytical results show that the volatile elements such as Pb and Zn were not lost during the preparation of glass bead. Low dilution glass bead digestion technique described here will be very helpful to enhance precision and accuracy of trace element analysis for geological samples containing refractory minerals.