• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.85-94
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• 2012

Evaluation of the smear effect caused by mandrel penetration into soft ground for a vertical drain installation is very important to predict the consolidation time of soft ground improvement. 30 kinds of laboratory model tests considering in situ conditions were conducted to investigate the formation of a smear zone and the decrease of coefficient of permeability in the disturbed zone. Three types(C(clay):M(silt)=1:1, 0.5:0.5, and 0:1) of reconstituted samples were used for 3 dimensional smear zone test. An experimental study was performed focusing on length of mandrel penetration, mandrel shape and size, earth pressure, and ground condition(unit weight and grain size distributions). Laboratory test results show that the length of mandrel penetration is the most critical factor for the formation of smear zone. As a result, the ratio between diameter of the smear zone($d_s$) and that of mandrel($d_m$) at field using long mandrel becomes larger than conventional $d_s/d_m$. The ratio between $d_s$ and $d_m$ ranges from 1.89 and 2.48 with the sample at C:M=1:0. It was also found that the $d_s/d_m$ value with the round shape of the mandrel is smaller than that of diamond one. The value of $d_s/d_m$ decreased with larger mandrel size, lower unit weight, and higher earth pressure. However, higher silt content led to increase of $d_s/d_m$. The ratio between coefficient of horizontal permeability in the smear zone($k_{hs}$) and that of undisturbed zone($k_{ho}$) ranged from 0.70 to 0.85. The test results imply that factors and values affecting $k_{hs}/k_{ho}$ show similar tendency with $d_s/d_m$.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.185-190
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• 2016

Damages of the main engine aftmost bearing and the after stern tube bearing tend to increase due to misalignment. And as the shafting system becomes stiffer due to the large engine power, whereas the hull structure becomes more flexible due to optimization by using high tensile thin steel plates. And this is the reason that more sophisticated shaft alignments are required. In this study, the optimum shafting alignment calculation was carried out, considering the thermal expansion effect, exploiting the sensitivity index, which indicates the reasonable position of forward intermediate shaft bearing for shaft alignment. and as the main subject in this study, the elastic deformation on intermediate shaft and main engine bearings occurred by vertical load of shaft mass were examined thoroughly and analyzed allowable load of bearings, reaction influence numbers of all bearings. As the result, a reliable optimum shafting alignment was derived theoretically. To verify these results, they were referred to the engine maker's technical information of main engine installation and being used shafting alignment programs of both Korean Register of Shipping and Det Norske Veritas, their reliability were reviewed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2503-2510
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• 2014

This study chiefly aims to find out the efficient ways of designing community facility convertible to refuge in case of emergency. In order to reach this goal, this study analyzed (1) definition of terminologies regarding disaster and refuge space, (2)present situation of regarding acts and standards, (3)function and spatial specialties of existing community facilities. Besides, in order to clarify the efficient design methods of 'function-convertible-type' community facility, this study executes archival research on (1)spatial requirements, (2)methods of designing futuristic community facility. When making design directives of community facilities, it is important to consider (1)vertical integration of rescue related function, (2)spatial division and architectural installation concerning privacy, (3)proper layout of locker room, shower room, toilet, etc. (4)appropriate size of unit space. It is desirable to execute the refuge function with minimum psychological anxiety in case of disaster through design guideline for 'function-convertible-type' community facility.

• Steel and Composite Structures
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• v.21 no.5
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• pp.1157-1182
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• 2016

A newly puzzle shape of crestbond rib shear connector is a type of ductile perfobond rib shear connector. This shear connector has some advantages, including relatively easy rebar installation and cutting, as well as the higher shear resistance strength. Thus, this study proposed a newly puzzle shape of crestbond rib with a "${\mho}$" shape, and its shear resistance behaviors and shear strengths were examined using push-out tests. Five main parameters were considered in the push-out specimens to evaluate the effects of shear resistance parameters such as the dimensions of the crestbond rib, transverse rebars in the crestbond dowel, concrete strength, rebar strength, and dowel action on the shear strength. The shear loading test results were used to compare the changes in the shear behaviors, failure modes, and shear strengths. It was found that the concrete strength and number of transverse rebars in the crestbond rib were significantly related to its shear resistance. After the initial bearing resistance behavior of the concrete dowel, a relative slip occurred in all the specimens. However, its rigid behavior to shear loading decreased the ductility of the shear connection. The cross-sectional area of the crestbond rib was also shown to have a minor effect on the shear resistance of the crestbond rib shear connector. The failure mechanism of the crestbond rib shear connector was complex, and included compression, shear, and tension. As a failure mode, a crack was initiated in the middle of the concrete slab in a vertical direction, and propagated with increasing shear load. Then, horizontal cracks occurred and propagated to the front and rear faces of the specimens. Based on the results of this study, a design shear strength equation was proposed and compared with previously suggested equations.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.234-238
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• 2008

Coarse pore filter could be an alternative of membrane for solid-liquid separation in an activated sludge reactor because of inexpensive cost of the filter material and high flux at low filtration pressure. However such filter module has much less specific filtration area compared to the membrane. Therefore a certain effort is required to increase the specific filtration area in the module design of such coarse pore filter for solid-liquid separation in an activated sludge reactor. In this study, tubular type coarse pore filter was designed at various diameter and configuration. The filtration performance was investigated to separate solid in the activated sludge reactor for domestic wastewater treatment. Tubular type coarse pore filter module could be successfully applicable to solid separation in the activated sludge reactor. The design parameters were the tube diameter of 10mm and vertical installation. Smaller diameter of the tube caused faster increase of the filtration pressure because of the hydraulic head loss in the tube channel.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.6
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• pp.529-536
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• 2010

Purpose: The Purpose of this study is to show the total survival rate of implants with maxillary sinus grafting and the effects that reach the survival rate by classifying types of graft materials, implant type, operation method, residual bone height and evaluate graft material resorption rate after sinus grafting Patients and Methods: 61 dental implants placed with sinus bone grafting in 24 patients at Wonkwang University Sanbon Dental Hospital were installed simultaneously or after regular healing. Various bone grafts (autograft, xenograft, allograft, alloplast) and fourth implant type (GSII, Xive, Implantium, Novel biocare) were used. All implants were investigated clinically and radiographically, being with average 20 months follow-up period after installation. Results: 3 fixtures were lost, resulting in 95.1% cumulative survival rate of 61 osseointegrated dental implant. Survival rate according to bone material type, Implant type, operation method, residual bone height, have no statistically significant differencies. The mean preoperative residual alveolar bone height was 4.75 mm, average postoperative height of graft materials 10.8 mm, vertical bone resorption rate was 10% after 2 years. Resorption rate according to operation method was 7% (simultaneous) and 5% (delayed) after 1 year. Conclusion: It can be suggested that maxillary sinus grafting may have predictable result with various bone graft materials and implant type, residual bone height, operation method

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.111-120
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• 1999

Leachate flow behavior due to intermediate cover soil of low hydraulic conductivity and the applicability of pumping method for reducing the leachate level in the landfill are analyzed with the numerical flow model, MODFLOW. Using the hydraulic conductivity and storativity data obtained from the field pumping and slug tests(Jang and Cho, 1999), the hydraulic condition within the landfill is validated. The optimum rate of pumping, the radius of influence, and the efficiency of horizontal drain are analyzed for reducing the leachate level in the landfill. From the results of the analyses, the barrier effect that the buried cover soil of low hydraulic conductivity prevents the vertical movement of leachate flow through the cover soil, which is found from the in-situ geotechnical studies(Jang and Cho, 1999), is identified again. Also, the installation of horizontal drains to the pumping well can increase the pumping rate from 120 ton/day per a well to 300 ton/day. The length of horizontal drain did not influence significantly on the drawdown-time curve of leachate in the landfill.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.285-294
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• 2002

Embankment Piles, which is subjected to damage due to lateral movement of soft ground, can be classified into pile slab, cap beam pile, and isolated cap pile according to the installation pattern of pile cap. In the cap beam pile and the isolated cap pile method, the soil arch is developed by the different stiffness between pile and soil, and most embankment loads are transferred into embankment piles through soil arch. In these two methods, the difference of soil arch is that the soil arch of the cap beam pile method develops like the arch from of tunnel between cap beams and the soil arch of the isolated cap pile method develops like dome between isolated caps. Therefore, theoretical analysis methods on soil arching effect of the cap beam pile and the isolated cap pile method were respectively proposed according to their own arch form considering the limiting equilibrium of stresses in a crown of soil arch. And a series of model tests were performed both to investigate the load transfer by soil arching in fills above embankment piles and to verify the reliability of the theoretical analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.50-55
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• 2017

Foamed aluminum is an eco-friendly material that is reusable and safe against fire. These superior characteristics have many advantages in the field of building and construction and in cruise ships as sound absorbers. So far, the research on foamed aluminum has been focused on the sound absorption performance using the foaming ratio. Foamed aluminum, when compared with the existing sound absorbers such as glass wool or rock wool, has a better structural performance, and it can be installed on walls in many different ways. This study conducted experiments on the sound absorption characteristics considering the various applications of foamed aluminum. The effects of painting surfaces with the finishing material were compared to that of the normal surface, and the effects of vertical installation and hanging from the ceiling was compared with the effects of installing on the floor.

• Korean Institute of Interior Design Journal
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• v.18 no.5
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• pp.175-182
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• 2009

Korea Protestant slower growth and social church's changes in the environment of the traditional worship center for the sermon to a variety of changes was required, because of this period reflects the availability of a new type of worship was to appear. These changes in the type of worship in the form of the worship space, and space configuration is affecting many more. This study was the type of church korea today, the type is classified as a traditional worship and contemporary worship, and to characterize the category by a change in the type of church worship space in the configuration that affects cases throughout the analysis was to investigate, study follows. Traditional worship the center of the altar, the altar placed platform form, a vertical elevation of the platform sheet form, the installation of the cross, place the side of the choir seats, church chair type attribute appears tradition and in part compressed pulpit appears symbolism. Contemporary worship to the exclusion of the symbolic elements of the platform open, flat sheet form and the platform was the preferred form of minor elevations of the flat, multi-purpose space used for worship to sermon platform placed around the altar of the adjustable type, the choir seats placed in scheelite, preferred form of scheelite was an individual chair. However, the characteristics of traditional and contemporary worship space features a mix of worship space, quite a lot of cases that have been found. Integrated and consistent element of the worship space, the worship of the discrepancy in the form of systematic theological depth analysis did not come true without lust about contemporary culture is changing rapidly to accommodate sprawl is judged. Therefore, the characteristics of the type of worship and prayer to understand the changes in the church building is a prerequisite to be a very important aspect.