• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.425-431
• /
• 2009

Antimicrobial coating on chicken carcasses may reduce the effects of cross-contamination and improve product shelf-life and safety. Thyme oil was mixed at 0.5%(v/v) with a pre-gelatinized pea starch coating solution. The coating solution was spread on chicken breast meat after inoculation with selected spoilage and pathogenic bacteria. After inoculation, the chicken meats were packaged in plastic bags and stored at $4^{\circ}C$. During 12 day storage, total aerobic bacteria, lactic acid bacteria, and inoculated organisms were counted at 4 day intervals. Thyme oil treatments reduced the viability of Salmonella as well as the growth of Listeria and Pseudomonas by 2 log CFU/g, and appeared to eliminate inoculated Campylobacter during storage. The addition of thyme oil increased the viscosity of the pre-gelatinized pea starch solution. The results suggested that thyme oil inclusion in an edible starch coating may be a satisfactory delivery system to enhance the safety of processed fresh meat.

• Journal of Korean Society of Water and Wastewater
• /
• v.24 no.5
• /
• pp.561-572
• /
• 2010

The efficiency of biological hydrolysis at $80^{\circ}C$ on municipal solid waste mixed with anaerobic digestion sludge was investigated in 100L batch reactors. The hydrolysis effect was observed within a day, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, and the effect was observed during two days, When the reactor used for post-treatment reactor. For both configurations, methane production rate decreased, when hydrolysis was carried out more than a day. Gaseous ammonia in the hydrolysis reactors was successtully removed by the ammonia stripping system. Microbial diversity analysis on the hydrolysis reactors indicated dependency of microbial diversity on the configuration of the hydrolysis reactors. Carbohydrate and lactate degrading microbes dominated in the hydrolysis reactor, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, while protein degrading microbes dominated in the post-treatment reactor.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.6
• /
• pp.109-116
• /
• 2004

In this study, when variable-amplitude load with various applying mode acts on the pre-crack tip, we examined how fatigue cracks behave. Hence aspects of the deformation caused by changing the applying mode of single overload and propagation behavior of fatigue crack were experimentally examined: What kinds of the deformation would be formed at pre-crack and its tip\ulcorner What aspects of the residual plastic deformation field would be formed in front of a crack\ulcorner How aspects of the plastic zone could be evaluated\ulcorner As applying mode of single overloading changes, the deformation caused by tensile and shear loading variously showed in each applying mode. The different aspects of deformation make influence on propagation behavior of cracks under constant-amplitude fatigue loading after overloading with various modes. We tried to examine the relationship between aspects of deformation and fatigue behavior by comparing the observed deformation at crack and crack propagation behavior obtained from fatigue tests.

• Clean Technology
• /
• v.20 no.3
• /
• pp.314-320
• /
• 2014

The purpose of this work is to optimize composition of mixture refrigerants used in the C3MR (Propane & Mixed Refrigerants) process by a statistical optimization technique. C3MR studied in this work is one of widely used commercial natural gas liquefaction processes with high efficiency. Process simulation was performed in a commercial process simulator and methane ($C_1$), ethane ($C_2$), propane ($C_3$), and nitrogen ($N_2$) were selected as mixed refrigerants. Using the process model, optimum composition of refrigerants mixture was determined via mixture design and central composite design to produce minimum energy consumption. As a result, it was confirmed that energy consumption is reduced down to 11.3% comparing to existing design. It was also compared with heat effectiveness through temperature profile of MCHE (main cryogenic heat exchanger).

• Transactions of Materials Processing
• /
• v.27 no.1
• /
• pp.5-11
• /
• 2018

Direct energy deposition (DED) technique uses a laser heat source to deposit a metal layer on a substrate. Many researchers have used the DED technique to study the hardfacing of molds and dies. The aim of this study is to obtain high surface hardness and a sound bonding between the AISI M4 deposits and a substrate utilizing a mixed powder that contains M4 and AISI P21 powders. To prevent interfacial cracks between the M4 deposits and the substrate, the mixed powder is pre-deposited onto a JIS S45C substrate, before the deposition of M4 powders. Interfacial defects occurring between the deposits and substrate and changes in the microhardness of the intermediate layer were examined. Observations of the cross-sections of deposited specimens revealed that the interfacial cracks appeared in samples with one and two mixed layers regardless of the mixture ratio. However, the crack was removed by increasing the mixture ratio and the number of intermediate layers. Meanwhile, the microhardness in the mixed layer was found to decrease with increasing ratio of P21 powder in the mixture and that in the upper region of the deposited layers was approximately 800 HV, which was attributed to various alloying elements in the M4 powder.

• The Research Journal of the Costume Culture
• /
• v.13 no.5 s.58
• /
• pp.686-698
• /
• 2005

In this study, simultaneous mordanting method of dyeing in the Caesalpinia sappan dye liquor mixed with the rice straw ash solution was employed. The dyeing effects were compared and reviewed according to the changes of dyeing mechanisms of pre-mordanting and simultaneous mordanting using ash solutions. By the direct addition of the ash solution, the pH of the liquor was abruptly changed. In the case of maintaining the pH value of the ash solution at about 7 or 8, compared to the pre-mordanting, $a^{*}$ values increased and $b^{*}$ values decreased. As a result, it is highly desirable in terms of selective emphasis on the reddish hue. The color development, differentiated from that obtainable by the dyeing of chitosan pre-treated fabric, was obtained due to the effect of the water soluble chitosan component on the dyeing mechanism.

• English Language & Literature Teaching
• /
• v.16 no.3
• /
• pp.141-160
• /
• 2010

This study aims to analyze the effects of explicit lexical collocation instruction on grammatical collocation knowledge, by focusing on the preposition collocations. The forty participants consisting of twenty men and twenty women are currently freshmen English majors in college. They responded to the questionnaire on their basic lexical learning strategies in pre-post tests, and carried out a lexical collocation test and a preposition collocation test as pre-post tests. They took the open class on the lexical collocations(LC) 5 times, but they did not concretely study any grammatical collocations(GC). Each test is analyzed and compared with pre-post tests by SPSS 12.0. From all the analyses, it was first revealed that most students who didn't know about the concepts, types and uses of collocations became aware of them after the class. The effects of the lexical collocations on the lexical collocation knowledge were quite revealing. Second, the correlations between the lexical collocations and grammatical collocations were not significant, although relations among the lexical collocations were quite significant. Finally, some suggestions for methods of mixed lexical chunks instruction are made for students' productive skills. Also, it is suggested that more profound attention should be paid to giving direct instructions on the basis of the lexico-grammatical continuum between LC and GC.

• Journal of Forest and Environmental Science
• /
• v.36 no.4
• /
• pp.259-266
• /
• 2020

Poplar trees from the Salicaceae family over the years have been utilized for various reasons which include prevention of deforestation as well as phytoremediation. This study aims to determine the optimal pre-treatment and soil conditions required for propagation of poplar cuttings for increased initial adaptability and survival rate. Five poplar clones (Hanan, 110, 107, DN-34, 52-225) were selected for IBA, soil composition treatments on propagation. IBA pre-treatment of cuttings were utilized 0, 10, and 100 mg l-1 concentrations. Soil compositions were amended with TKS-2+perlite 2:1 (v:v) and sandy clay loam mixed with artificial soil. According to the greenhouse results 10 mg l-1 of IBA showed a significant increase in plant height whereas 100 mg l-1 inhibited plant growth except in clone 110. Soil composition severely affected root growth and hence overall growth of the clones. Sandy clay loam soil had poor to stunted growth compared to TKS-2+perlite.

• Educational Technology International
• /
• v.19 no.2
• /
• pp.175-197
• /
• 2018

Flipped classroom (FC) has gained attention as an active learning approach. Designing effective out-of-class activities to help prepare students for in-class activities is fundamental for successful implementation of FC. This study investigated the effectiveness of Goal-Based Scenarios (GBS) for out-of-class learning in FC. Four out of twelve units in a medical humanities course for Year 2 medical students was redesigned into a FC format, where e-learning modules were designed using a GBS approach for out-of-class activities and classroom debates were implemented for in-class activities. The other eight units were delivered in a conventional classroom debate format, which included reading text materials as pre-class assignments. A formative evaluation study was conducted using questionnaires and interview methods and students' academic achievements were evaluated by comparing their pre- and post-test scores between FC and conventional units. Students had positive perceptions of the e-learning modules in GBS approach and preferred the structure of learning in the FC format. Students' pre-test scores were slightly higher in the FC units, yet their post-test scores were comparable with conventional units. This study illustrates students' perceptions that the learning was bettered structured in FC and that the out-of-class learning using the GBS approach helped them better prepared for in-class activities.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.4
• /
• pp.235-242
• /
• 2005

This study is on the evaluation of performance of polymer cement mortar which is used for pre-wetting spray method. Pre-wetting spray method is an epoch-making method to repair concrete structures damaged, which is added a small quantity water preciously to dry mortar to reduce dust and rebound and spray mortar mixed with fixed quantity water at nozzle before spray. The result showed that physical performance such like compressive, flexural and adhesive strength of polymer cement mortar, TS 100 used for pre-wetting spray method was superior to other repair mortar. Also durable performance such as resistance on permeability of chloride ion, carbonation, chemical and freezing-thawing was excellent.