• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1373-1380
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• 2010

The plate loading test(PLT) and the field density test are mainly used on the construction of embankments to control the compaction of a limited layer thickness. These two test methods are very time consuming and inefficient, but they are still commonly used as the methods of quality control for soil compaction. In the last 3 decades, many devices such as geogauge, light falling weight deflectometer(LFWD) and dynamic cone penetrometer(DCP) etc., have been introduced into the engineering market with the objective of acquiring in situ stiffness properties of the compacted soil layers. Recently, a new type of sensor, called compactometer, which in mounted on the drum of a roller and measures impact forces continuously with GPS, called as Continuous Compaction Control(CCC), has come into use in many countries such as America, Germany, Japan and so on. The main objective of this paper is to assess the potential use of these new devices as quality control and assurance devices for compacted soil layers. Based on this study, compactometer and the LFWD results werestrongly correlated with the result obtained from the PLT and the field density test.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.173-182
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• 1998

This study was conducted to evaluate the effect of plant growth inhibitors on "Penncross" creeping bentgrass in the green of golf course for increasing the summer quality. Chlormequat chloride (C) 250$\times$, 500$\times$, 1000$\times$, daminozide (D) 50$\times$, 100$\times$, 200$\times$, paclobutralzol (P) 1000$\times$, 2000$\times$, 4000$\times$, trinexpac-ethyl (T) 1000$\times$, 2000$\times$, 4000$\times$, uniconazole (U) 25$\times$, 50$\times$, 100$\times$ with three concentrations, respectively, were applied to creeping bentgrass. The leaf length, leaf width, and internode length of stolon were inhibited by all plant growth retardants applied as compared to that of control in which D-50, T-2000, and trinexpac-ethyl were the most effective among treatments on the inhibition of leaf length and internode length of stolen, respectively. Leaf thickness increased more in the treatments of C-250, D-50. T-2000 and T-4000 than any other treatments. On the other hand, shoot density which was represented by number of leaves per unit area was found to be the highest in P-2000 and P-4000 treatment. In this case, all plant growth retardants with no significant differences showed increase of 15-20% in density as compared to control. Total dry weight increment was higher in P-2000 and P-4000 while leaf dry weight increment was higher in T-4000. and U-25 and 50 than other treatments. According to the visual evaluation for the purpose of turf quality measurement, it was found that paclo-butralzol, trinexpac-ethyl and uniconazole were not suitable for green maintenance and extension because of making leaves to yellow. In conclusion, it was postulated that C-250, D-50, and T-4000 had possibility to use practically in the green area of golf course.lf course.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.219-226
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• 2020

Nondestructive testing is one of the most commonly used quality inspection methods for evaluating ship structures. However, accurate evaluation is dif icult because various composite materials, such as reinforcements, resin, and fiber-reinforced plastics (FRPs), are used in hulls, and manufacturing quality differences are likely to exist owing to the fabrication environment and the skill level of workers. This possibility is especially true for FRP ships because they are significantly thicker than other structures, such as automobiles and aircraft, and are mainly manufactured using the hand lay-up method. Because the density of a material is a critical condition for ultrasonic inspection, in this study, a hull plate was selected from a vessel manufactured using e-glass fiber, which is widely used in the manufacture of FRP vessels with the weight fraction of the glass content generally considered. The most suitable ultrasonic testing conditions for the glass FRP hull plate were investigated using a pulse-echo ultrasonic gauge. A-scans were performed with three probes (1.00, 2.25, and 5.00 MHz), and the results were compared with those of the hull plate thickness measured using a Vernier caliper. It was found that when the probe frequency was higher, the eco-pulse velocity of the receiver had to be lowered to obtain accurate measurement results, whereas fewer errors occurred at a relatively low probe frequency.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.139-152
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• 2006

A spent fuel storage cask is required to prove the safety of a canister under a hypothetical accidental drop condition. A hypothetical accidental drop condition means that a canister is assumed to be a lee drop on to a pad of the storage cask during loading it into a storage cask. A pad of the storage cask absorbs shock to maintain the structural integrities of a canister under a hypothetical accidental drop condition. In this paper a finite element analysis for various pad structures was carried out to improve the structural integrity of a canister under a hypothetical accidental drop condition. A pad of a storage cask was designed a steel structure with concrete. The 1/4 height of a pad was modified with a structure composed of a steel and a polyurethane foam as a impact limiter. The effect of a shape of a steel structure was studied. The effects of the thickness of a steel structure and the density of a polyurethane foam was also studied.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.302-308
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• 2005

Nitrate is one of common contaminants frequently found in the bank filtrate. Biological autotrophic denitrification into permeable reactive barrier(PRB) system to reduce nitrate concentration in bank filtrate was implanted. The objectives of research are to investigate effect of inoculation, to evaluate alternative alkalinity sources, and to determine effect of hydraulic characteristics, such as retention time, flow rate on the performance of semi-pilot PRB system. Semi-pilot scale biological PRB system was installed using elemental sulfur and limestone/oyster shell as reactive materials near Nakdong River in Kyoungnam province, Korea. Nitrate concentration in bank filtrate was reduced by indigenous microorganisms in oyster shell as welt as by inoculating microorganisms isolated from the sludge of an anaerobic digester in a wastewater treatment plant. Oyster shell as well as limestone can be used as an alkalinity source. However, oyster shell resulted in suspended solids of effluent. As the flow rate in the system increased from 66 to 132 mL/min and accordingly the residence time decreased from 15 to 7.5 hours, nitrate concentration in effluent increased and nitrate removal efficiencies decreased from 75 to 58% at the fixed thickness of 80 cm of PRB.

• The Korean Journal of Pesticide Science
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• v.20 no.2
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• pp.83-92
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• 2016

New tree wound-treatment formulations (WTF) were developed in this study. Stimulating effects of plant growth regulating substance on callus formation were evaluated in vivo twig disc culture of Zelkova serrata, Ziziphus jujuba, Pinus densiflora, Ginkgo biloba. and Aesculus turbinata. Based on the evaluation, WTF were prepared with 2,4-D, NAA, and IBA using xanthan gum as an extending agent. WTF were pasted on $2{\times}10cm$ artificial wound on the stem and the effects were evaluated 12 weeks later with the thickness of new callus-tissues. The effects varied with tree species and the growth regulators. In Z. serrata and A. turbinata, 2 mg/L of 2,4-D was the best WTF. In P. koraiensis and G. biloba, 8 mg/L of NAA and 1 mg/L of IBA were the best, respectively. Callus formation was quite lower in G. biloba compared to other species. Stimulating effect of thiophanate-methyl paste was excellent only in Z. serrata and lower than certain WTF in other species. Vaseline, which was used generally as an WTF, remained longer on the wound and causing decay. From the results, it could be recommended that 2,4-D, NAA and IBA were the best WTF for Z. serrata/A. turbinata, P. koraiensis and G. biloba, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.42-50
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• 2016

Overlay welding affects the chemical components and weld hardness by dilution of the lamination layer thickness, which determines the surface properties. This study experimentally investigates different numbers of layers for overlay welding monel materials, which are anti-corrosion materials. The Fe content, weldability of the base metal and monel materials, hardness, and surface flatness were examined. Each evaluation was carried out after overlay welding with three layers on the base material and pipe base material of the plate. The Fe content was evaluated by analyzing the constituents of each layer. The Fe content was satisfactory in the three layers. The weldability of the laminate specimens was evaluated by a bending test. The hardness and bead flatness of the laminate specimens were evaluated by micro Vickers and 3D measurements. The hardness was highest in the heat-affected zone with one layer, and it decreased with increasing lamination. In the case of bead flatness, there is a sharp difference in the deviation with increasing numbers of laminations, which should be considered carefully.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.45-55
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• 2016

Light shows various optical behaviors such as reflection, absorption, and scattering on skin for individuals. In particular, reflection of light from the skin has been widely used as the brightness index of the skin of individuals through the measurement of the physical quantity of spectral reflectance. Therefore, the study of light behavior on skin would be useful for the preparation of new evaluation method in the development stage of make-up products. In this study, multi-dimensional analysis for spectral reflectance behavior of light on individual skin was performed using Kubelka-Munk model. Also, we analyzed the contribution of skin parameters such as skin thickness and hemoglobin, which could affect the spectral reflectance, using above model and literature information. Base on this, we calculated the theoretical reflectance of normal women for visual light, which showed good agreement with the measured reflectance. Our study of light propagation in skin based on Kubelka-Munk model provides useful insight for the development of personalized cosmetic in the near future.

• Membrane Journal
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• v.26 no.4
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• pp.281-290
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• 2016

Thin film composite (TFC) polyamide membranes were prepared on polysulfone (PSF) supports for forward osmosis (FO) applications. To understand the influence of polarity and porosity of support layer on the formation of polyamide structure and the final FO performance, clathochelate metal complex (MC) contained PSF supports were prepared via the phase inversion process from various PSF casting solutions containing 0.1-0.5 wt% of MC in dimethyl formamide (DMF) solvent (18 wt%). A crosslinked aromatic polyamide layer was then fabricated on top of each support to form a TFC membrane. For the porous PSF supports prepared with relatively low concentration casting solutions (12 wt%), the PET film was removed after phase inversion and crosslinked aromatic polyamide layer was then fabricated. The tested sample from PSF (18 wt%)/MC (0.5 wt%) casting solution presented outstanding FO performance, almost similar water flux (9.99 LMH) with lower reverse salt flux (RSF, 0.77 GMH) compared to commercial HTI FO membrane(10.97 LMH of flux and 2.2 GMH of RSF). By addition of MC in casting solution, the thickness of the active layer in FO membranes was reduced, however, the increased RSF value was obtained.

• Progress in Medical Physics
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• v.9 no.1
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• pp.1-9
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• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).