• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.237-245
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• 2009

The purpose of this study was to investigate the clinical efficacy of latex cover developed for dental handpiece on contamination of microorganisms during dental treatment and to determine whether it can be an alternative to conventional sterilization such as autoclaving. E. fecaelis was used as a experimental microorganism instead of oral flora. Experimental bowl with 2 cm of rectangular cavity was fabricated for handpiece operating instead of oral cavity. Latex covers ($Orokeeper^{(R)}$, Orobiotech Co., Korea) and several handpieces were used after sterilization by autoclave. Four experiments were performed to evaluate bacterial contamination related with (1) various parts of dental handpiece, (2) swabbing time with alcohol sponge, (3) postoperative air-water spraying time and (4) consecutive use of latex covers without autoclaving. The results show that face of handpiece uncovered with latex cover was severely contaminated than the covered area and that most bacteria were removed by swabbing face and head area of dental hand-piece and by air-water spraying more than 15 seconds nearly up to the level of sterilization. Conclusively it can be suggested that use of latex cover for handpiece during dental procedure, swabbing with alcohol sponge is air-water spraying for more than 15 seconds after use of dental handpiece should be very useful and practical for prevention of cross infection and should be an alternative method for the sterilization of dental handpiece under some difficult situations not being able to sterilize a handpiece with autoclave.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.1
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• pp.115-127
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• 2024

This research aimed to construct models with various structures based on the Transformer module and to perform land cover classification, thereby examining the applicability of the Transformer module. For the classification of land cover, the Unet model, which has a CNN structure, was selected as the base model, and a total of four deep learning models were constructed by combining both the encoder and decoder parts with the Transformer module. During the training process of the deep learning models, the training was repeated 10 times under the same conditions to evaluate the generalization performance. The evaluation of the classification accuracy of the deep learning models showed that the Model D, which utilized the Transformer module in both the encoder and decoder structures, achieved the highest overall accuracy with an average of approximately 89.4% and a Kappa coefficient average of about 73.2%. In terms of training time, models based on CNN were the most efficient. however, the use of Transformer-based models resulted in an average improvement of 0.5% in classification accuracy based on the Kappa coefficient. It is considered necessary to refine the model by considering various variables such as adjusting hyperparameters and image patch sizes during the integration process with CNN models. A common issue identified in all models during the land cover classification process was the difficulty in detecting small-scale objects. To improve this misclassification phenomenon, it is deemed necessary to explore the use of high-resolution input data and integrate multidimensional data that includes terrain and texture information.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.2
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• pp.31-39
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• 2019

Cracked component analysis is needed for structural integrity analysis under seismic loading. Under large amplitude cyclic loading conditions, the change in material properties can be complex, depending on the magnitude of plastic strain. Therefore the cracked component analysis under cyclic loading should consider appropriate cyclic hardening model. This study introduces a procedure for determining an appropriate cyclic hardening model for cracked component analysis. The test material was nuclear-grade TP316 stainless steel. The material cyclic hardening was simulated using the Chaboche combined hardening model. The kinematic hardening model was determined from standard tensile test to cover the high and wide strain range. The isotropic hardening model was determined by simulating C(T) test under cyclic loading using ABAQUS debonding analysis. The suitability of the material hardening model was verified by comparing load-displacement curves of cyclic C(T) tests under different load ratios.

• Asian Journal of Turfgrass Science
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• v.9 no.4
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• pp.293-316
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• 1995

Nitrogen fertilization and cutting practice were studied on turfgrasses and cover plants to investigate the possibility of maintaining green color during the growing season. Research also involved the effect of the nitrogen on a few morphological characteristics of leaf performance elements which might give an information to coloration and life-span of turf leaves. Treatments in the first experiment undertaken on pot included one N level: 350kgN /ha applied as compound fertilizer in split applications of one-half in mid-May and the rest both in late June and August, and four spring-summer cuts: late May, late June, late July and late August. The soil filled in pot a moderately well-drained sandy loam. In the second experiment(field observation) leaf length and width, inflorescence and flowering, and color performance were also investigated. With nitrogen fertilizer applied on turfs, desirable turf color was maintained during a period of poor coloration in specific seasons such as mid-summer for cool season grasses and late fall for warm season grasses comparing to the non-treatment. However, this was not stimulated by cutting treatment to nitrogen status existed. Cutting effect on coloration was more remarkable in both Korean lawngrass and Manilagrass than in cool season turfgrasses such as Italian rye-grass, perennial ryegrass and tall fescue. Especially down-slide of leaf color in cool season turfgrasses could he detected in mid-summer /early fall season ranging up to mid-September. In early November as well as mid-September, Italian ryegrass, perennial ryegrass and tall fes-cue retained a high level of green color as followed by nitrogen application and cutting treatment, and little detectable variation of leaf color notation between cool season turfgrasses was obtained. However, Korean la'vngrass and Manilagrass failed to retain the green color until early November. Color notations in cool season turfgrasses investigated early November on the final date of the experiment ranged from 5 GY 3/1 to 4/8 in 'Ramultra' Italian ryegrass, 'Reveile' perennial ryegrass and 'Arid' tall fescue, but those in Zoysiagrasses were 7.5 YR 4/8 in Korean lawngrass and 2.5 y 5 /6 in Manilagrass. Life-span of leaves was shorter in Italian ryegrass, perennial ryegrass and tall fescue than in beth Korean lawngrass and Manilagrass with and without nitrogen application. In general, leaves appeared in early May had a long life-span than those appeared in late April or mid-June. Nitrogen application significantly prolonged the green color retaining period in perennial ryegrass, Italian ryegrass, Korean lawngrass and Manilagrass, and this was contrasted with the fact that there was no prolonged life-span of leaves emerging in early May and mid-June in tall fescue. SPAD reading values in 48 turfs and cover plants investigated in the field trial were increasing until late June and again decreasing till September. Increasing trends of reading value could be observed in the middle of October in most of grasses. On the other hand, clovers and reed canarygrasses did not restore their color values even in October. Color differences between inter-varieties, and inter-species occurred during the growing season under the field condition implicated that selection of species and /or cultivars for mixture should be taken into consideration. In Munsell color notation investigated in the final date in the middle of November, 32 cultivars belonged under the category of 5 GY and 10 cultivars under the category of 7.5 GY. This was implying that most of cool season turfs and cover plants grown in the center zone of Korean Peninsula which are able to utilize for landscape use can bear their reasonable green color by early or mid-November when properly managed. The applicable possibilities of SPAD readings and Munsell color notation to determine the color status of turfgrasses and cover plants used in this study were discussed.

• Journal of the Korean GEO-environmental Society
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• v.9 no.6
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• pp.5-12
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• 2008

In this research, the plate load tests on sand which is reinforced by Tirecell mat were simulated by finite element method (FEM). Tirecell mat made by waste tires has the same function and similar shape to Geocell for soil reinforcement and it can also be used for civil engineering structure. The results were compared with those of field plate load tests for evaluation of suitability of modeling method. From the comparison of both results, it can be seen that the settlements by FEM were very similar to test results with small margin under the ultimate bearing capacity. For the ultimate bearing capacities of two results, difference was very small. After the confirmation of the modelling, reinforcing effects with variation of cover depth and number of reinforcement layers by Tirecell were analyzed additionally. Reinforcing effect decreases with increasing soil cover depth, and this is similar to previous test results by soil cover depth. As the number of reinforcing layers increased, reinforcing effect increased. However at more than 2 reinforcing layers, reinforcing effect was negligible. In conclusion, the modeling method in this research might be used for analysis of reinforced structures using Tirecell mat.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.2
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• pp.139-143
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• 1995

Two hundred eighty weaned Targhee lambs were grazed on annual grass-subclover pastures for 84 d under continuous and rotational defoliation grazing system. At the end of the grazing season, twenty lambs weighing 44 kg were slaughtered directly off the pasture, whereas two groups of 20 lambs each were fed either a alfalfa pellet or a 50% alfalfa/50 concentrate pellet for additional 6 wk until they reached an average live weight of 50 kg. Carcass traits and loin chop palatability were compared. Lambs slaughtered directly off the pasture were lighter than desirable market weight and some lambs had less than adequate fat cover and approximately half of them were graded U.S. Good in quality. Overall conformation and leg muscling was inferior and loin chops were less tender, less juicy and less flavorful. The lambs on alfalfa pellets for 6 wk appeared to be ideal in terms of carcass quality (all Choice except one), fat cover and yield grade. They had better taste panel scores in all palatability traits than off-the-pasture lambs, and most loin chops were acceptable. The lambs on a 50% concentrate diet for 6 wk had a higher conformation score and a greater muscling in the legs. Loin chops had more marbling and better palatability than other groups. However, some lambs had an excessive fat cover and lower yield of retail cuts. It was concluded that additional feeding for 6 wk on alfalfa pellets until the live weight reached 50 kg(for Targhee lambs) was the best way of finishing lambs at the end of grazing season in the California rangeland.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.785-791
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• 2009

Using artificial rainfall simulator, the soil loss, which is deemed as the most cause of muddy water problem among Non-point source (NPS) pollutant, was studied by the analysis of direct runoff, groundwater discharge, and soil water storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared soil as slope increases from 5% to 20%. The direct runoff volume from straw covered surface were much lower than bared surface. The infiltration capacity of straw covered surface increased, because the surface sealing by fine material of soil surface didn't occur due to the straw covering. Under the same rainfall intensity and slope condition, 2.4~8.2 times of sediment yield were occurred from bared surface more than straw covered surface. The volume of infiltration increased due to straw cover and the direct runoff flow decreased with decrease of tractive force in surface. To understand the relationship of the rate of direct runoff, groundwater discharge, and soil water storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, except between the rate of groundwater storage and rainfall intensity.

• Steel and Composite Structures
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• v.33 no.6
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• pp.849-864
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• 2019

One way to achieve sustainable construction is to reduce concrete consumption by use of more sustainable and higher strength concrete. Modern building codes do not cover the use of ultra-high strength concrete (UHSC) in the design of composite structures. Against such background, this paper investigates experimentally the mechanical properties of steel fibre-reinforced UHSC and then the structural behaviors of UHSC encased steel (CES) members under both concentric and eccentric compressions as well as pure bending. The effects of steel-fibre dosage and spacing of stirrups were studied, and the applicability of Eurocode 4 design approach was checked. The test results revealed that the strength of steel stirrups could not be fully utilized to provide confinement to the UHSC. The bond strength between UHSC and steel section was improved by adding the steel fibres into the UHSC. Reducing the spacing of stirrups or increasing the dosage of steel fibres was beneficial to prevent premature spalling of the concrete cover thus mobilize the steel section strength to achieve higher compressive capacity. Closer spacing of stirrups and adding 0.5% steel fibres in UHSC enhanced the post-peak ductility of CES columns. It is concluded that the code-specified reduction factors applied to the concrete strength and moment resistance can account for the loss of load capacity due to the premature spalling of concrete cover and partial yielding of the encased steel section.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.197-206
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• 2010

Recently, developed countries have continuously been trying to recognize many issues about heat island in urban area and to make up countermeasures for them. This research is designed to extract change of land cover in the area under condition of land development with satellite images and to analyze its effect on the heat change in there. Heat change upon change of land cover in daejeon was analyzed with the four Landsat satellite images taken in April 1985, August 1994, May 2001, and May 2009. In order to measure the temperature on the surface in the city, the land surface temperature was produced with Landsat TM Band 6. Heat change is to detected with it. As a result, The urban area has been increased up to 23.59 percent. On the other hand, the forest area has been decreased up to 27.91%. Due to the urbanization, the temperature on the surface in urban center was higher than surrounding area. In that case, the temperature of urban center area was higher 2.4 to $5.7^{\circ}C$ compared with the forest area.

• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.13-17
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• 2008

The Congo has a maritime coastline of 40 km, covering an area of $2,345,409km^2$. The fluvial system covers around $34,000km^2$ in a network of more than 33,000 km of rivers, principal tributaries, and streams. There are around 1,000 known species of fish, essentially freshwater and some brackish. The lakes of the Rift Valley contain the richest lacustrine fauna in the world. The family of Cichlidae alone has more than 900 species. At the same time, the lakes are profoundly different. Lake Tanganyika has 250 species of fish, of which 216 are endemic, whereas Lake Kivu contains only 32 and 16, respectively. A dense hydrographic network of water surfaces, inundated plains and lakes cover around $86,080km^2$ (3.5% of the national area) and have a considerable aquatic potential. The large peripheral lakes of the East cover around $48,000km^2$ of which 47% are under Congolese jurisdiction. The respective areas belonging to the Congo are: Lake Tanganyika, $14,800km^2$; Lake Albert, $2,420km^2$; Lake Kivu, $1,700km^2$; Lake Edward, $1,630km^2$; Lake Mo$\ddot{e}$ro, $1,950km^2$. Another two important lakes in the interior, Lake Tumba and Lake Mai-Ndombe, cover (between them) 2,300 and $7,000km^2$, depending on season (less in the dry season and more in the rainy season). There are also the lakes of the Kamalondo depression ($6,256km^2$), Lake Tshangalele ($446km^2$) and Lake N'Zilo ($280km^2$).