• Journal of the Korean Geotechnical Society
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• 제24권10호
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• pp.147-160
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• 2008

This paper presents the results of full-scale loading tests performed on 54 passive anchors and 4 group anchored footings grouted to various lengths at several sites in Korea. The test results, the failure mechanisms as well as uplift capacities of rock anchors depend mostly on rock type and quality, embedded fixed length, properties of the discontinuities, and the strength of rebar. Anchors in poor quality rocks generally fail along the grout/rock interfaces when their depths are very shallow (a fixed length of less than 1 m). However, even in such poor rocks, we can induce a more favorable mode of rock pull-up failure by increasing the fixed length of the anchors. On the other hand, anchors in good quality rocks show rock pull-up failures with high uplift resistance even when they are embedded at a shallow depth. Laboratory test results revealed that a form of progressive failure usually occurs starting near the upper surface of the grout, and then progresses downward. The ultimate tendon-grout bond strength was measured from $18{\sim}25%$ of unconfined compressive strength of grout. One of the important findings from these tests is that the measured strains along the corrosion protection sheath were so small that practically the reduction of bond strength by the presence of sheath would be negligible. Based on test results, the main parameters governing the uplift capacity of the rock anchor system were determined. By evaluation of the ultimate uplift capacity of anchor foundations in a wide range of in situ rock masses, rock classification suitable for a transmission tower foundation was developed. Finally, a very simple and economical design procedure is proposed for rock anchor foundations subjected to uplift tensile loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제30권5B호
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• pp.437-444
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• 2010

Soil moisture has been recognized as the essential parameter when understanding the complicated relationship between land surface and atmosphere in water and energy recycling system. It has been generally known that it is related with the temperature, wind, evaporation dependent on soil properties, transpiration due to vegetations and other constituents. There is, however, little research concerned about the relationship between soil moisture and these constitutes, thus it is needed to investigate it in detail. We estimated the soil moisture and then compared with field data using the hydrometerological data such as atmospheric temperature, specific humidity, and wind obtained from the Flux tower in Selmacheon, Korea. In the winter season, subterranean temperature showed highly positive correlation with soil moisture while it was negatively correlated from the spring to the fall. Estimation of seasonal soil moisture was compared with field measurements with the correlation of determination, R=0.82, 0.81, 0.82, and 0.96 for spring, summer, fall, and winter, respectively. Comprehensive relationship from this study can supply useful information about the downscaling of soil moisture with relatively large spatial resolutions, and will help to deepen the understanding of the water and energy recycling on the earth's surface.

• Journal of the Korean Society of Safety
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• 제21권4호
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• pp.73-84
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• 2006

Standard safety management cost system was established in 1988 as a decree Number of 88-13, first time. And then, it has been revised fourteen times, up to now. A lot of practical investigations have been made for the revision but many problems at sites are continued to be put out so that it should be revised. This study is to find out hazard level of each work kinds through questionnaire and interview and investigate analyze the status which standard safety management costs have been used. Also, this study is to show reasonable rates of standard safety management costs in construction industry and to set up countermeasures against those problem after reviewing its status in korea with in Japan and Europe. Budget and actually performed amount of safety management costs in this study are investigated. costs for temporary work which is clarified in Japan is collected in order to compare domestic cost rate with Japanese one related to the total project amount. This study is to investigate eleven project kinds of domestic system, first, and to investigate eleven items of apartment bldg, office, civil work such as bridge, tunnel, dam, plant etc, secondly. Additionally, three items of gymnasium, railway, particular steel tower are investigated in this study. Also this study is to investigate and analyze performed costs of presently processing worker finished work so that it shows a new reasonable rate against standard safety management costs in construction industry, in order to make basical data and material to be systemized.

• Computers and Concrete
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• 제8권3호
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• pp.293-309
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• 2011

A long-term structural health monitoring (SHM) system comprising over 700 sensors of sixteen types has been implemented on the Guangzhou Television and Sightseeing Tower (GTST) of 610 m high for real-time monitoring of the structure at both construction and service stages. As part of this sophisticated SHM system, 48 temperature sensors have been deployed at 12 cross-sections of the reinforced concrete inner structure of the GTST to provide on-line monitoring via a wireless data transmission system. In this paper, the differential temperature profiles in the reinforced concrete inner structure of the GTST, which are mainly caused by solar radiation, are recognized from the monitoring data with the purpose of understanding the temperature-induced structural internal forces and deformations. After a careful examination of the pre-classified temperature measurement data obtained under sunny days and non-sunny days, common characteristic of the daily temperature variation is observed from the data acquired in sunny days. Making use of 60-day temperature measurement data obtained in sunny days, statistical patterns of the daily rising temperature and daily descending temperature are synthesized, and temperature distribution models of the reinforced concrete inner structure of the GTST are formulated using linear regression analysis. The developed monitoring-based temperature distribution models will serve as a reliable input for numerical prediction of the temperature-induced deformations and provide a robust basis to facilitate the design and construction of similar structures in consideration of thermal effects.

• Transactions of the Korean Society of Mechanical Engineers B
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• 제40권5호
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• pp.289-296
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• 2016

The availability of NMP, a solvent used in the manufacturing process of cathode material for lithium ion battery, depends on importation, and the price remains high because of the monopoly of BASF and ISP. For these reasons, most Lithium ion battery manufacturers reuse NMP after recovering it from the exhaust air in the drying process. In Korea, absorption method is mainly used for recovering NMP from the absorption tower using the hydrophilicity of NMP. However, this system has a few disadvantages, such as low purity (80％) of the recovered NMP and 100％ emission due to high water content of the treated gas. In this study, we develop a hybrid NMP recovery system by combining cooling condensation method with concentration method, by which it is possible to obtain an NMP recovery rate of 99.6％, and a high purity (96.1％) of the recovered NMP.

• Korea Journal of Hospital Management
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• 제15권3호
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• pp.143-169
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• 2010

This is a case study of Seoul St. Mary's Hospital applying a real-time enterprise (RTE) strategy to improve customer satisfaction and operational efficiency with the main process of medical institutions. The hospital is applying an RTE strategy to get real-time information on occurrences at each contact point of the main process of the medical institution from reservation to discharge through dashboard and to resolve issues through rapid decision-making. The RTE strategy of the hospital has some summaries: First, the hospital has linked a hospital management strategy to the RTE strategy to build a patient-centered treatment process. Second, the hospital has operated a control tower for change management and implementation monitoring in the process of implementing the RTE strategy. Third, the hospital has built systematic RTE-based environment as an application program in which the nU System is linked to Business Processor Renovation (BPR) promoted from 2006 on. Fourth, the hospital is applying a strategy to improve efficiency in operating the hospital by increasing customer satisfaction, removing inefficiency and variability, and managing medical resources efficiently through the RTE strategy. Fifth, it has established an information-sharing system through authority management for each user in terms of RTE information. Sixth, it has supplemented limitations of short-term information of the RTE strategy by linking the key performance index to the cost information system in order to improve performance of the RTE strategy. Seventh, it has improved customer satisfaction and achieved higher performance in improving operational efficiency, as compared with rival hospitals, through the RTE strategy.

• Journal of Korean Society of Forest Science
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• 제98권6호
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• pp.799-805
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• 2009

To construct the production system of forest biomass as a small scale heating energy source, energy availability of wood-chip was examined by cost and energy balance analysis in the production process. The costs to produce wood-chip of 1 kg was calculated by yarding machines and their operational gradient conditions. As a result, 195.45~210.54 won/kg were required as production costs of wood-chip. Input energy rate (%) which is output to input energy in wood-chip production process were showed as 26.58~27.38%. Energy input rate by operational gradient was not significantly difference, and scenario B with tower yarder system appeared by more efficient than scenario A with tractor yarding system in opposition to production costs analysis.

• Applied Chemistry for Engineering
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• 제21권3호
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• pp.295-300
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• 2010

A binary system of 1-propanol and bromochloromethane which exhibits an azeotropic point and a considerable nonideal phase behavior probably due to the large boiling point difference is not amenable in the actual chemical processes such as the distillation tower and absorber. Therefore, experimental data of phase behavior data of this mixture are indispensable in understanding the inherent thermodynamic characteristics for an efficient application of the system in the industrial processes. In this work, the isobaric vapor-liquid equilibrium of a binary mixture consisting of 1-propanol and bromochloromethane was measured by using a recirculating equilibrium cell at various pressures ranging from 30 to 70 kPa. The measured VLE data were correlated in a satisfactory manner by using the UNIQUAC and NRTL models along with the thermodynamic consistency test based on Gibbs/Duhem equation. In addition, the excess molar volume of the mixture was also measured by using a vibrating densitometer and correlated with a Redlich-Kister polynomial.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.768-773
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• 2009

Measuring method being applied for off-shore works is performed by using data logger or manual measuring instrument with wiring the cable connected from the sensor up to the position where measuring is allowed.(upper part of embankment or marine structure) Measuring management by using existing measuring method may be acceptable on the condition that the ground deformation volume(vertical, horizontal) is generally minimal and the site condition is good. But loss of measuring instrument, sensor cable failure or cutting is taken place frequently due to significant change of ground behavior caused by an external force change(embankment, excavation) under very soft ground condition(N value below 0-4). In case of the marine works, in particular, loss rate of measuring instrument is highly represented due to the factors of working barge anchoring, constructional interference and natural disaster. In order to solve these problems, measuring management was performed with employing underground wireless system at the immersed tunnel site. Measuring data was obtained freely under the marine environment by using underground wireless communication and cable cutting potential by ground behavior could be reduced. Measuring cost savings and its installation convenience were maximized by way of off-shore tower installation or cabling and by minimizing constructional interference of off-shore working barge. This case of measuring management was accomplished successfully.

• Journal of Hydrogen and New Energy
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• 제22권1호
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• pp.13-20
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• 2011

$SO_2$ has been absorbed and separated selectively by an ionic liquid from $SO_2/O_2$ mixture decomposed from sulfuric acid during the thermochemical SI cycle for the water splitting. In order to design and operate high pressure $SO_2/O_2$ separation system, the solubility of $SO_2$ in [EMIm]$EtSO_4$ (1-ethyl-3-methylimidazolium ethylsulfate) has been measured by Magnetic Suspension Balance at high pressure and temperature. Based on the measured solubility, a pressurized separation system was set up and operated. 194 L/h of $SO_2$($SO_2:O_2$=0.65:1) has been separated with 99.85% of $O_2$ at the vent of absorption tower, which is 22.7% of the theoretically ideal capacity of the system. This discrepancy results from the reduced contact between the gaseous $SO_2$ and the ionic liquid. Increased $SO_2$ supply, scale-up of the absorption column, and a faster ionic liquid circulation speed were suggested to improve the separation capacity.