• Resources Recycling
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• 제14권4호
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• pp.47-52
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• 2005

Carbonate species in aqueous solution play an important role in the determination of chemical properties of water in relation with alkalinity, buffer capacity, biological productivity, and so on. These compounds also have reactive characteristics such as interphasal reactions between solid, liquid, and gas phases. In the absence of solid materials, the total amount and relative abundance of each carbonate species are directly influenced by the partial pressure of $CO_2$ gas in the atmosphere, which in turn significantly affects the properties of aquatic system. In the water/wastewater treatment process along with the wastes treatment and recycling process which occurring in aquatic environment, it is essential to figure out its characteristics for their optimization and one of its most influential features upon these processes is determined by carbonate species. To understand the fundamental aspect of the relationship between the partial pressure of $CO_2$ gas and chemical features of water, especially pH, the working partial pressure of pure $CO_2$ gas that produced by contacting the dry ice with water has been estimated based on equilibrium calculation. The equilibrium constants for the dissociation ot carbonic acid were determined using van't Hoff equation and the distribution diagram of carbonate species according to the pH has been constructed to substantiate the results of equilibrium calculation. The estimated working partial pressure of pure $CO_2$ gas was found to be a function of the concentration of carbonates in solution, which suggesting that Prior evaluation of the working partial pressure of gas is essential for a better understanding of aquatic interactions.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제38권2호
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• pp.261-268
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• 2018

The study used the simplified flooding analysis model, SIMOD, to distribute the total flood discharge by time, so research on flooding in urban areas can be conducted. The conventional flooding analysis models have limitations in constructing input data and take a long time for analysis. However, SIMOD is useful because it supports rapid decision-making process using quick modeling based on simple hydrological data, such as topography and inflow flood of the study area, to analyze submerged routes formed by flooding. Therefore, the study used the SIMOD model to analyze flooding in urban areas before conducting a comparative study with the outputs from FLO-2D, which is one of the conventional flooding analysis models, to identify the model's applicability. Seongseoje was selected as the study area, as it is located downstream the Geumho river where streams flow in the adjacent areas, and dikes are high enough to apply the "Overflow and Break" scenario for urban areas. With regard to topography, the study applied DEM data for the conventional flooding analysis and DSM data to represent urban building communities, distribution of roads, etc. Input flood discharge was calculated by applying the rectangular weir equation under the bank and break scenario through a 200-year return period of a design flood level. Comparative analysis was conducted in a flooded area with a simulation time of 1-24 hours. The time for the 24-hour simulation in SIMOD was less than 7 minutes. Compared with FLO-2D, the difference in flooded areas was less than 20%. Furthermore, the study identified the need for topography data using DSM for urban areas, as the analysis result that applies DSM showed the influence of roads and buildings.

• Journal of Distribution Science
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• 제12권12호
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• pp.75-82
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• 2014

Purpose - Due to the rapidly changing environment, the needs of information distribution are emphasized more than ever before. As information changes to cater to diversity, professionalism, and detailed segmentation, this information is produced exponentially. Many researchers working in intelligence agencies are feeling the need to establish a comprehensive information management and information distribution system in a systematic and more effective manner. Mobile marketing is based on communication when consumers can access information using GPS systems whatever their location may be when they are on a trip. Until recently, Korean companies have been struggling to perform well in the larger mobile tourism information service (MTIS) for Chinese tourists, which is regarded as a blue ocean area. The principal dimensions of the characteristics of a mobile tourism information service were analyzed, and the influence on perceived value and satisfaction was identified. Moreover, the relationship among the variable satisfaction and using intentions was empirically analyzed. Research design, data, and methodology - This study examined the structural relationship among mobile tourism information features, perceived value, satisfaction, and behavioral intentions. It is based on analyzed data from questionnaires involving advanced research. A questionnaire survey targeting Chinese students using a mobile tourism information service in Korea was conducted. A total of 230 questionnaires were circulated, and 221 questionnaires were used for empirical analysis, excluding invalid data. The data were analyzed with structural equation modeling with SPSS 21.0 statistic package reliability analysis, factor analysis, and regression analysis were implemented, and the effects of the mobile tourism information service features on perceived value, satisfaction, and using intentions were presented. Results - First, mobile tourism information service features have a direct positive effect on the practical value, and do not affect the hedonic value. Second, perceived value has a statistically positive effect on satisfaction. Third, perceived value has a positive effect on behavioral intentions. Fourth, satisfaction has a direct positive effect on behavioral intentions. Conclusion - MTIS (mobile tourism information service) involves personal, social, and technical characteristics. We have analyzed the effects of mobile tourism information service on perceived value, and on satisfaction and using intentions. First, the study shows that the characteristics of mobile tourism information service and perceived value in relation to mobile tourism information service usage are important for marketing in the Chinese market. Moreover, after using a mobile tourism information service, the effect on practical value is more than on hedonic value. We could not analyze the program for tourism information service extensively, and used only questionnaires from Chinese students in Korea. In the future, there should be research on the programs for a tourism information service. We expect to study the MTIS program in greater detail, and to improve the quality and reputation of MTIS through the analysis of its program. We hope that this research will allow an evaluation of the relationship between Korea and China regarding MTIS.

• Journal of the Korea Concrete Institute
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• 제27권6호
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• pp.651-659
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• 2015

Currently, social demands for long span building structures are increasing due to architectural planning purposes and economic efficiency. As a result, lighter board-type voiding materials were suggested. With the use of board-type voiding materials, a slab is able to become light weight and convenient. This process efficiently eliminates concrete where it is not required; considerably diminishing dead weight while maintaining the flexural strength of the slab. The reduction in concrete also allows for overall cost reductions and design flexibility. Also it can be ease with fixing the voided material that is composed of one body form. Although board-type voiding materials are ideal, the top and bottom concrete plates lack integrity. Because of this, test results show horizontal cracking towards the tops and bottoms of the concrete columns, or webs, connecting the slabs. The key to correcting this problem is to increase the shear strength. In order to increase the shear strength of the structure, horizontal shear area must increase. R70(100)-D-F has the largest horizontal shear area as it also shows stronger strength. As a result, shear strength ($V_{nh}$) is dependent on the horizontal shear area (N). $V_{nh}={\alpha}{\times}0.16{\sqrt{f_{ck}}}{\frac{{\pi}D^2}{4}}{\times}N({\alpha}=1.8125)$. The web columns have a shear span to depth ratio (a/d) that is less than 2; which classifies it as a deep beam. In this case, however, the shear strength of the deep beams may be as much as 2 to 3 times greater than that predicated conventional equations developed for members of normal proportions. As a result, ${\alpha}$ is suggested as an extra coefficient in the equation for shear strength ($V_{nh}$).

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1036-1040
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• 2005

Near-infrared reflectance spectroscopic (NIRS) calibrations were developed for accurate and fast prediction of whole broiler chicken carcass composition. The Feed and Forage Foss systems Model 5000 Reflectance Transport Model 5000 with near-infrared reflectance spectroscopy (NIRS)-WinISI II windows software was used for this purpose. One equation was developed for the prediction of each carcass component. One hundred and fifty freeze dried broiler whole carcass samples were ground in a Cyclotech 1,093 sample mill and analyzed for dry matter, protein, fat, calcium and phosphate. Samples were divided into two sets: a calibration set from which equations were derived and a prediction set used to validate these equations. The chemical analysis values (mean${\pm}$SD) were calculated based on dry matter basis as follows: dry matter: 33.41${\pm}$2.78 (range: 26.41-43.47), protein: 54.04${\pm}$6.63 (range: 36.20-76.09), fat 35.44${\pm}$8.34 (range: 7.50-55.03), calcium 2.55${\pm}$0.65 (range: 0.99-4.41), phosphorus 1.38${\pm}$0.26 (range: 0.60-2.28). One hundred and three samples were used to calibrate the equations and prediction values. The software used was modified to obtain partial least square regression statistics, as it is the most suitable for natural products analysis. The coefficients of determination ($R^2$) and the standard errors of prediction were 0.82 and 1.83 for the dry matter, 0.96 and 1.98 for protein, 0.99 and 1.07 for fat, 0.90 and 0.30 for calcium and 0.91 and 0.11 for phosphorus, respectively. The present study indicated that NIRS can be calibrated to predict the whole broiler carcass chemical composition, including minerals in a rapid, accurate, and cost effective manner. It neither requires skilled operators nor generates hazardous waste. These findings may have practical importance to improve instrumental procedures for quick evaluation of broiler carcass composition.

• International Journal of Highway Engineering
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• 제20권1호
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• pp.87-95
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• 2018

PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS : From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empirical-mechanical finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analy pavement-design analysis using thesis and bonding property tests using cored specimens from public roads will be conducted in further research.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제41권7호
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• pp.629-634
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• 2017

In the case of the UHP (Ultra high performance) tire that the demand has increased rapidly, compared with the commonly used tire, severe deformation has been observed because of the low aspect ratio. When repeated deformations are applied to the sidewall rubber, accumulated fatigue damage may cause fatigue failure. Thus, the evaluation of the durability of the tire sidewall rubber has become a very important issue to prevent accidents that occur while the vehicle is running. However, the research and design criteria for the durability performance of the tire sidewall rubber hardly exist. In this study, we suggest a lifetime prediction formula using strain energy density obtained by performing tensile tests and fatigue tests on two different kinds of the tire sidewall compounds. Additionally, the applicability of our findings for low fuel consumption tires was reviewed by converting the fatigue life of the sidewall rubber into the expected mileage of the tire.

• Journal of the Korean Society of Hazard Mitigation
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• 제8권3호
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• pp.51-58
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• 2008

Development of a new design guide which is based on empirical-mechanistic concept for pavement design is in action. It is called AASHTO 2002 Design Guide in USA and the KPRP(Korean Pavement Research Project) in Korea. The material characteristic of hot mix asphalt is a key role in the design guide. Therefore it is urgent to get a proper materials database, especially the dynamic modulus of hot mix asphalt. In this research, dynamic modulus test, which is based on aged asphalt binder, has been carried out and proposed the predicted equation of dynamic modulus. Nine different hot mix asphalt with three different asphalt binder have been used for the dynamic modulus test. Short-term aging, which is covers the time for the production of asphalt plant, transportation, lay-down, and compaction, can be simulated at $135^{\circ}C$ with 2 hour curing. Long-term aging has been carried out for a performance period of asphalt pavement. The dynamic modulus of asphalt pavement increases with aging time. As the nominal aggregate size increases, the change of dynamic modulus is not big.

• Journal of the Korean Geotechnical Society
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• 제32권6호
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• pp.49-59
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• 2016

We develop liquefaction resistance curves, which represent the correlation between cyclic resistance ratio (CRR) and number of cycles (N) to estimate the build-up of residual excess pore pressure from simple shear tests performed for this study and also from published literature. The liquefaction curve is calculated from two models. The comparisons show that one of the models is not reliable because it underestimates CRR. The scatter of the data is shown to be significantly reduced when CRR is normalized to the resistance ratio at N = 15 ($CRR_{N=15}$). Use of the normalization is particularly useful because CRR can be easily estimated from field tests. From normalization, we propose mean, upper, and lower curves. The corresponding design equation and its parameters are also proposed. We believe that the proposed curves can be used for effective stress site response analyses and evaluation of the seismic performance of port structures.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제62권2호
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• pp.79-86
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• 2017

This study was conducted to analyze seasonal and annual variations in rice quality and factors affecting the quality, for quality evaluation of the brand rice varieties produced in Jeonnam region. Coefficient of variation (CV) values for the seasonal variation in the rice quality were 3.1% in Toyo value, 2.1% in whiteness, 1.6% in protein content, 1.0% in moisture content, and 0.4% in head rice ratio. Quality characteristics of the brand rice varieties generally showed a decreasing tendency after April, as the months progressed. CV values for the annual variation in the rice quality were relatively high at 5.6% in protein content and 5.2% in Toyo value whereas those for whiteness and head rice ratio were relatively low, at 2.7% and 1.8%, respectively. Palatability and protein content showed high correlations with minimum air temperature, sunshine hours, rainfall, and daily temperature range. Head rice ratio had a negative correlation with daily temperature range whereas chalky rice ratio had a positive correlation with rainfall. Based on these results, we formulated a multiple regression equation to estimate palatability of cooked rice using protein content, whiteness, head rice ratio, and moisture content as follows: y = - 6.71a + 2.27b + 1.29c + 0.51d - 15.34 ($R^2$=0.51*) (y: palatability of cooked rice, a: protein content, b: moisture content, c: whiteness, d: head rice ratio).