• International Journal of Highway Engineering
• /
• v.11 no.2
• /
• pp.141-149
• /
• 2009

This study was conducted to investigate the causes that induce the T-shape cracks at the joints in the jointed concrete pavements(JCPs). The finite element models of JCP including dowel bars were developed and the stress distribution in the slab was investigated under environmental loads. To investigate the effect of dowel bars on the transverse stresses at the joints that induce the T-shape cracks, the slab curling behavior was analyzed with and without dowel bars. In addition, the stress concentration was investigated when the dowel bar was not installed at the mid-depth of the slab. The results of this study showed that the transverse stresses were not affected by the dowel bars if the dowel bars were installed at the mid-depth of the slab. However, if the dowel bars were not installed at the mid-depth, the transverse stresses were concentrated at the dowel bar locations when the slab curled. The stress concentration was dependent on the contact characteristics between the dowel bar and concrete, and was significantly large when the dowel bar not installed at the mid-depth was located far from the edge of the slab. Therefore, to mitigate T-shape cracking in JCP, dowel bars should be very carefully installed and leveled at the proper locations.

• Journal of Food Hygiene and Safety
• /
• v.15 no.4
• /
• pp.315-323
• /
• 2000

Serious consequences can arise from lack of hygiene in mass catering. Microbiological testing is of value in determining hazards for developing a HACCP plan, and in demonstrating to food handlers the reality of the microbial risk. This studies was performed to describe the overall hygiene of cooking utensils and equipments, employees, and environment in mass catering establishments. Generally, hygienic conditions of cutting board and sanitized dish cloth were better than those of other cooking utensils such as knife, sieve, and peeler. It was found that the cross-contamination of knife might be caused by the use of contaminated sanitizing solution. It was observed that there was considerable variation (10$^1$~10$^{5}$ CFU) of the number of general bacteria for employee's hands. The number of general bacteria were influenced from establishment, employee, and the period of analysis. The number of Coliform group for employee's hands was in the range of 10$^2$~10$^4$CFU only at the first analysis. Total aerial bacteria in working area of mass catering establishments was below 7 CFU/Plate and aerial Staphylococcus sp. was not detected at all except one spot.

• Korean Journal of Medicinal Crop Science
• /
• v.4 no.3
• /
• pp.241-246
• /
• 1996

This Experiment was conducted to know effect of cutting times and nitrogen split application rates on shoot and root-related characters of Atractylodes japonica. The cutting time was forced on none, once and twice along with three levels of nitrogen split application, all basic 50 -30 -20% and 40 -30 -30%. The plant height declined with increased cutting time and dry matter weight was increased with nitrogen split application under none and once cutting. Average yield of cutted shoot as edible wild plant was 257kg/10a at once cutting condition, but twice cutting condition was little and unfavorable to use edible wild plant because shoot was coarse. Yield 0 dry rhizome was the highest at once shoot cutting und­er 50 -30 -20% nitrogen split application by 471kg/10a.Especially, culture of Atractylodes japonka needed once shoot cutting one the 10th-30th of May.

• International Commerce and Information Review
• /
• v.19 no.1
• /
• pp.235-256
• /
• 2017

This study is to analyse how trust and asset specificity among partner firms affect on performance of international joint venture(IJV). Especially, the analysis was mainly based on a quadratic model. While it assumes that the previous studies was based on linear model in the relationship between trust, asset specificity and the performance, this study proceeds a empirical analysis by setting up a hypothesis; it would be quadratic relationship between trust, asset specificity and performance which are based on social capital theory and transaction cost theory. The survey was held with 74 manufactures who were established as an IJV by Korean and foreign firms together. In the result of the empirical analysis, trust shows an inverted U-shaped relationship with IJV performance. Also, asset specificity shows the U-shaped relationship with IJV performance. The results suggest that it needs to control and maintain the trust level among the partners in order not to lose an appropriate control caused by too much trust. In order to minimize the cost generated by asset specificity and to transform it into positive impact, it needs a control and the operation of monitoring system on the opportunistic action of the partners. Furthermore, it needs to keep organizational flexibility and innovativeness to continuously develop new capabilities.

• KSBB Journal
• /
• v.15 no.3
• /
• pp.285-292
• /
• 2000

Support media for yeast immobilization was prepared from a porous volcanic rock used as a moisturizer in orchid growing. The rock was broken to the size of 2-3 mm and burned at $600^{\circ}C$ in a furnace in order to remove organic materials blocking the pores or treated with HCI solution or NaOH solution to remove the inorganic dirts by dissolving. Even through both the acid and the akali solution were effective the latter was not recommendable because it broke the pore structure by dissolving the elements of the media. This media was mainly consisted of SiO2 with $Al_2O_3$ as a minor component and CaO and K2O as trace elements. It had the finely developed pores of $15-80\mu\textrm{m}$size. Yeast immobilization capacity of this media was about $5{\times108}$ cells/ml bed which is large enough to be used for the practical applications. Yeast immobilization capacities of Alumina and Cordierite were much smaller than that of silica-based media. Scanning electron micrograph of Cordierite and Alumina showed uneven surfaces and small size of pores in contrast to relatively smooth surface and large pores of silica based media which means that smooth surface and large pores are desirable for the good adsorption of microbes on the media.

• Journal of the Korea Institute of Building Construction
• /
• v.17 no.4
• /
• pp.341-348
• /
• 2017

The performance degradation of concrete pavement by winter deicer is very serious in Korea, and its maintenance and rehabilitation brings a high expense. Therefore, a suitable method for rehabilitation of such concrete pavement and repair material of proper performance are required. In this study, the properties of compressive strength, ability to resist chloride ion penetration, and properties of dry shrinkage of magnesium phosphate ceramics were assessed to evaluate its applicability as a repair material for concrete pavement in Korea. As a result, the mortar flow showed a normal level of 190 mm, but the viscosity was high and the self-flow ability was poor. The setting time was 12 minutes, leading very rapid-hardening, and thus a prompt work was required. The compressive strength of mortar was 38.4MPa in 2 hours, 73.8MPa in 24 hours, and 111.0MPa in 28 days, showing a significant level. As a result of the test to chloride ion penetration resistance, mortar showed 143 Coulombs, and concrete showed 172.6 Coulombs, which fell under very low level. The drying shrinkage of MPC concrete in 40 days was below $60{\times}10-6$, and comparing with normal cement concrete, it showed the level below 1/10 of other concrete to secure an excellent volume stability. As above, magnesium phosphate ceramics has excellent strength performance, chloride ion penetration resistance, and volume stability, and this in the future shall be used in construction under the consideration of working time or workability, requiring further improvement for such performance.

• Journal of Mushroom
• /
• v.8 no.4
• /
• pp.161-164
• /
• 2010

For the development of a sporeless strain of P. ostreatus we used sporeless strain ASI 2069. We have recovered both nuclear types of strain ASI 2069 as monokaryons of nh9, nh15, nh26 and nh36 (here after referred to as neohaplonts) by protoplasting the mycelium. Crosses between neohaplonts and SSI's(single spore isolates) obtained from a sporulating commercial strain ASI 2180. Five excellent strains are selected from 30 bred strains by quality of fruitbodies and spore number. To development of molecular markers linked to sporeless strain of P. ostreatus, we are screened helicase, recombinase(DMC1) and topoisomerase(Spo11) genes related meiosis by PCR and sequencing. Among three genes, Spo11 gene was identified into molecular marker of sporeless from neohaplonts and bred strains of P. ostreatus.

• Archives of design research
• /
• v.13 no.4
• /
• pp.163-174
• /
• 2000

issued in the U.S is a magazine specialized in graphic design, which has a totally different style from commercial magazines such as show case. The main motive why Rudy VanderLans, the publisher, first issued this magazine in the early 1980s is his assertion that there is no design paradigm of universial concept in the aspect of viaual communication design. Also, it started from his recognition that a medium for letting a new generation's show their liberal thinking and experimental expressions. This study looks at theologies and assertions on new graphic concept, which is called the New Wave of graphic design by classifying the plans of into form and contents, and analyzes its specialty in design. Also, this study examines the overall trends of non-Grid editorial design since the modern style. By doing so, I could have a general look at the progressive traits and their futuristic directions that become to have a shorter life cycle with the advent of the 21st century's information era, high-tech media and the change of production environment by digital technology.

• Journal of Food Hygiene and Safety
• /
• v.16 no.2
• /
• pp.103-110
• /
• 2001

Predictive food microbiology(PFM) is an emerging area of food microbiology since the later 1980’s. It does apply mathematical models to predict the responses of microorganism to specified environmental variables. Although, at present, PFM models do not completely developed, models can provide very useful information for microbiological responses in HACCP(Hazard Analysis Critical Control Point) system and Risk Assessment. This study illustrates the possible use of PFM models(PMP: Pathogen Modeling Program win5.1) with milk in several elements in the HACCP system, such as conduction of hazard analysis and determination of CCP(Critical Control Points) and CL(Critical Limits). The factors likely to affect the growth of the pathogens in milk involved storage fixed factors were pH 6.7, Aw 0.993 and NaCl 1.3%. PMPwin5.1 calculated generation time, lag phase duration, time to level of infective dose for pathogens across a range of storage (Critical Control Points) and CL(Critical Limits). The factors likely to affect the growth of the pathogens in milk involved storage temperature, pH, Aw and NaCl content. The factors likely to affect the growth of the pathogens in milk involved storage temperature, pH, Aw and NaCl content. The variable factor was storage temperature at the range of 4~15$^{\circ}C$ and the fixed factors were pH 6.7, Aw 0.993 and NaC 1.3%. PMPwin5.1 calculated generation time, lag phase duration, time to level of infective dose for pathogens across a range of storage temperature.

• Journal of Food Hygiene and Safety
• /
• v.31 no.5
• /
• pp.342-348
• /
• 2016

The objective of this study was to compare the change of S. Enteritidis with S. Typhimurium populations in liquid egg products. S. Enteritidis or S. Typhimurium was inoculated into egg white and egg yolk and stored at 8, 10, 15, 25, and $35^{\circ}C$, respectively. In egg white, no growth of S. Enteritidis and S. Typhimurium was observed at 8, 10, 15, and $35^{\circ}C$, while both S. Enteritidis and S. Typhimurium in egg white stored grew more than 1 log CFU/ml after 50 hours storage at $25^{\circ}C$. In egg yolk, there was no growth of S. Enteritidis and S. Typhimurium at $8^{\circ}C$ but growth of both strains was observed at 10, 15, 25, and $35^{\circ}C$. Since growth of S. Enteritidis and S. Typhimurium was only observed in egg yolk, primary growth models for both strains were developed using modified Gompertz equation and then secondary models for lag time (LT), specific growth rate (SGR), and maximum population density (MPD) were developed as a function of temperature. At all temperatures, more rapid growth of S. Enteritidis than S. Typhimurium was observed in egg yolk, indicating the greater risk of S. Enteritidis than S. Typhimurium in egg products. In conclusion, the results indicate that temperature control less than $8^{\circ}C$ is very important to ensure safety of liquid egg products, especially liquid egg yolk.