• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.67-73
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• 2010

Paper packaging materials are essential in protection and transportation of commercial or industrial products. Raw materials for packaging paper production are mainly obtained from various grades of waste paper. For this reason, the recycled fibers from waste paper would probably have possibility of containing heavy metals. This study was focused on the development of optimum pre-treatment method for the quantitative analysis of mercury. The optimum pre-treatment for open digestion system were obtained at the treatment conditions of acid combination with $HNO_3/HCl/H_2O_2$ or $HNO_3/H_2SO_4$ at $80^{\circ}C$. The optimum pre-treatment conditions in closed digestion system were determinated by the acid combination with $HNO_3/HCl/H_2O_2/HF$ in microwave at 320 W for 20 min. The recovery rate in open digestion system was 85~94% and in closed digestion system was indicated as about 100%. Therefore, the closed system is superior than the open system in pre-treatment method for the quantitative analysis of mercury, and the detected mercury contents in the sample of KOCC, AOCC and kraft sack paper were measured below 1 ppm.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.413-424
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• 2014

The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade the technical quality and to enhance energy efficiency. The objective of this paper is to present efficient and effective pre-treatment methods of increasing the amount of produced biogas in anaerobic digestion of activated sludge treatment process. The paper also presents a review of the effect on biogas production between pre-treated and raw sludge, and also put forward the advantages and disadvantages of each pre-treatment method.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.101-109
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• 2015

Alpha spectrometry is typically used for the assessment of uranium particle concentrations and its accuracy can be directly related to the accuracy in which the radiochemical pre-treatment is conducted. Ashing and alkali fusion methods are typically used but the ashing method requires longer analysis time and the alkali fusion method is extremely costly. Therefore, a new pre-treatment method using ultrasonic cleaning was developed and its experimental result was compared against the two conventional methods in terms of pre-treatment time, convenience, cost, and recovery rate of a target material. The results that were obtained by the conventional methods(ashing and alkali fusion) and the new method were compared. Consequently, even though the shorter pre-treatment time was required, the new technique showed almost same recovery rate comparing with two conventional methods. The new method was also featured by its relatively lower cost and a simpler process than two conventional methods.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

• The Journal of Korean Physical Therapy
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• v.11 no.1
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• pp.71-77
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• 1999

The purpose of this study was to investigate the changes of muscle power by transcutaneous electrical nerve stimulation(TBNS), low frequency-low intensity(20pps, invisible muscle contraction intensity), low frequency-high intensity(20pps, visible muscle contraction), high frequency-low intensity(100pps, invisible muscle contraction intensity) and high frequency-high intensity(100pps, visible muscle contraction). The results were as follows. 1. Increased muscle power after 30 minutes of treatment by low frequency-low intensity TENS, and post-treatment 30 minutes muscle power were increased more than pre-treatment power(p<0.05). 2. Decreased muscle power after a 30 minute treatment by low frequency-high intensity TENS, and after the 30 minute treatment was terminated muscle power didn't recover to pre-treatment levels. 3. Decreased muscle power after 30 minute treatment by high frequency-low intensity TENS, but post-treatment 30 minute, muscle power didn't recover to pre-treatment levels. 4. The muscle power was remarkably decreased by high frequency-high intensity TENS after 30 minute treatment, in addition treatment terminated after 30minutes didn,t recover to pre-treatment power(p<0.05). 5. Lower frequency-low intensity TENS are good methods for preventing muscle fatigue, buty high intensity (TENS) are increased muscle fatigue. 6. Traditional TENS by high frequency-low intensity is a good method for preventing muscle fatigue.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.43-52
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• 2013

In this study, various influent sludge pre-treatment methods were adopted to investigate their effects on the sludge digestion and methane production in combined mesophilic anaerobic and thermophilic aerobic sludge digestion process. A lab-scale sewage sludge digestion process was operated during 4 phases using different feed sludge pre-treatment strategies. In phase 1, feed sludge was supplied without any pre-treatment. In contrast, in phases 2, 3 and 4, thermal, thermal-alkaline and long time alkaline treatment (7 days) were applied to influent sludge, respectively. With sludge pre-treatment, TCOD removal was drastically increased from 44% to 76% from phases 1 to 4, respectively. Also, pre-treatment of feed sludge significantly improved the methane production rate of MAD, showing an increment from 101 to 165-256mL/L/day. Meanwhile, TCOD removal and methane production at phase 4 were not increased, compared to those at phase 3. Based on the experimental results, it was concluded that pre-treatment of feed sludge significantly increases the efficiency of sludge digestion and thermal-alkaline method was the most effective method among the pre-treatment methods examined.

• Analytical Science and Technology
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• v.35 no.3
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• pp.129-135
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• 2022

We tested the pre-treatment of alumina, leucine, alumina mixed with leucine at ratios of 9:1 (Al-Leu (9:1)) and 5:1 (Al-Leu (5:1)), and alumina mixed with sodium lactate at a ratio of 5:1 (Al-Lac (5:1)) on aged fingerprints (1, 7, 14, and 30 days after natural fingerprinting) before cyanoacrylate (CA) fuming to improve the development efficacy. As a result of the experiment, fingerprints with pre-treatment of alumina, leucine, Al-Leu (9:1), Al-Leu (5:1), and Al-Lac (5:1) showed better development efficacy (area and minutiae) than fingerprints without pre-treatment. Therefore, this modified CA fuming method improved the development efficacy with five pretreatments.

• Food Science and Preservation
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• v.6 no.1
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• pp.1-6
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• 1999

Fresh gingers, harvested in Seosan, Choongcheongnam-do, were pre-treated by a washing-pasteurizing-drying process, a curing process, and non-treated, respectively. Then they were stored in a lab-scale storage room(12$^{\circ}C$, >92%RH) to investigate the effect of pre-treatment methods on the quality changes during long-term storage. Weight loss of ginger during storage showed ranges in 0.7∼4.3%, and the weight of gingers pre-treated by washing-drying process showed a tendency to change less than those treated by curing. After storage of 130 days, spoilage rates were about 20% in non-treated, 11% in curing treated, and 12% in washing-drying treated ginger,, showing the effect of pre-treatment. The final rate of sprouting was 13∼15% regardless of treatment methods. The firmness of gingers showed a tendency to decrease in stored ginger for the longer period; however, the values were ranged from 1,200 to 1,400 g/$\textrm{cm}^2$, that is hard enough to show a marketable quality. The contents of reducing sugar showed a tendency to increase with the lapse of storage time.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3313-3315
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• 1999

Si direct bonding(SDB) technology is very attractive for both Si-on-insulator(SOI) electric devices and MEMS applications because of its stress free structure and stability. This paper presents on pre-bonding according to HF pre-treatment conditions in Si wafer direct bonding. The characteristics of bonded sample were measured under different bonding conditions of HF concentration, and applied pressure. The bonding strength was evaluated by tensile strength method. The bonded interface and the void were analyzed by using SEM and IR camera respectively. A bond characteristic on the interface was analyzed by using IT- IR. Si-F bonds on Si surface after HF pre-treatment are replaced by Si-OH during a DI water rinse. Consequently, hydrophobic wafer was bonded by hydrogen bonding of Si $OH{\cdots}(HOH{\cdots}HOH{\cdots}HOH){\cdots}OH-Si$. The bond strength depends on the HF pre-treatment condition before pre- bonding (Min:$2.4kgf/crn^2{\sim}Max:14.9kgf/crn^2$)

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.171-177
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• 2013

Efficient extraction of total proteins from soil microorganisms is tedious because of small quantity. In this regard, an improved method for extraction of whole cell proteins is developed from soil microorganisms, Saccharomyces cerevisiae and Pichia pastoris. of which the cell wall are very strong. Pretreatment with NH4OH prior to the final extraction using NaOH/SDS was tried under the basis that ammonium ion was possible to enhance the permeability and/or to weaken the yeast cell walls. The pre-treatment of yeast cells with NH4OH drastically enhanced the protein extraction when it was compared with control (without NH4OH pre-treatment). At the pre-treatment of 0.04 N NH4OH at pH 9.0, about 3 fold of proteins was obtained from p. pastoris. Ammonium hydroxide appears to penetrate into the yeast cell walls more readily at basic pH. The effect of NH4OH pretreatment was pH dependent. The methods developed in this experiment might be applicable for an effective extraction of yeast proteins for the purpose of biochemical studies, especially proteomic analysis.