• Journal of ILASS-Korea
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• v.5 no.1
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• pp.30-40
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• 2000

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturated vapor pressure of the butane(0.23MPa at 298K). The ambient pressure was held at a pressure above(0.37MPa) and below(0.15MPa) the fuel vapor pressure. The axial velocities, radial velocities, and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. The PDPA measurement showed a smaller SMD at the 0.15MPa chamber pressure, compared to the 0.37MPa case. Log-hyperbolic density function for the droplets size distribution can be fitted to the experimental results of a liquefied butane spray.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.567-569
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• 2012

An inducing current of power feeding line of high-speed railway system is varied by a relative position of telecommunication cable to the feeding line between plants. An analytical calculation formula of this inducing current is described in ITU-T Directives using multiconductor line method or two line method. In this paper, using the two line method, a variation characteristic of inducing current is simulated. The inducing current has a characteristic of hyperbolic function which is a symmetric shape of curve in the range between power feeding plants. This basic variation property can be considered when a power induction protection measure is planned.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.93-101
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• 2020

In order to predict the nonlinear behaviour of the soil, the elasto-plastic hyperbolic model was selected, which was considered to be relatively simple and highly predictable. The soil parameter determination and the behavior analysis program were developed by formalizing the functions related to the constitutive model. Each soil parameter was determined from the results of the drained triaxial compression tests of Baekma river sand with the change of relative density. The stress-strain behavior was predicted using the soil parameters determined under each condition. As a result, the deviator stress for the axial strain is verified to have a good match between the measured value and predicted value at each relative density. In the relationship between the volumetric stain and the axial strain, when the relative density is loose, the measured value and predicted value tend to match, and when relative density is dense, the predicted value of the volumetric strain appears somewhat smaller than the measured value due to the limitation of the constitutive model.

• Journal of the Korean Geotechnical Society
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• v.25 no.9
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• pp.29-43
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• 2009

As computational technologies have been developed, the load transfer analysis method using load transfer curves is widely performed. Now the load transfer analysis methods are widely used in our country. But most of the curves using in the analysis have been developed in foreign countries. In this study we gathered the data of in situ pile load tests on domestic nine sites in order to derive load transfer curves of driven steel pipe piles. Then we derived average lines of $f/f_{max}$-w/D curves for sandy and clayey soils respectively, which are expressed by hyperbolic function. And the results using these curves and the results using TZPile 2.0 (Analysis program of pile) were compared and analyzed with the results of pile load tests on domestic 3 sites in order to ascertain the applicability of the curves. The results show that the load-settlement relations using the curves in this study are more similar to the measured data and more conservative than those using TZPile 2.0.

• Geotechnical Engineering
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• v.10 no.4
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• pp.83-102
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• 1994

For estimation of Ko value depending upon the stress history of dry sand, a new type of Ko oedometer apparatus is devised, and the horizontal earth pressure is accurately measured. For this study, 2 types of one-cyclic Ko loading/unloading models have been studied experimentally using four relative densities of the sand. The results obtained in this test are as follows Kon, the coefficient of earth pressure at rest for virgin loading is a function of the angle of internal friction of the sand and is determined as Kon=1-0.914 sin, Kou the coefficient of earth pressure at -rest for virgin unloading is a function of K. and overconsolidation ratio(OCR), and is determined as Kou : Kon(OCR)". The exponent u, increases as the relative density increases. Ko,, the coefficient of earth pressure at rest for virgin reloading decreases in hyperbola type as the vertical stress, cv', increases. And, the stress path at virgin reloading lends to the maximum prestress point, independent upon the value of the minimum unloading stress. The gradient of this curve, mr, increases as OCR increases.ases.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.5-11
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• 2007

Micropiles have been used for underpinning or rehabilitation of existing foundations, and direct structural support system as well. However, relatively few studies have been done on the load-transfer mechanism of micropile systems in Korea. In addition to that, only the limited information is available for estimating the side friction values on micropiles installed in weathered soils. In this study, a full-scale test on an instrumented micropile is performed in order to establish the load-transfer curves based on a hyperbolic function. Then, an empirically derived equation that correlates the load-transfer curve of micropiles with the N values from field standard penetration tests is proposed. The results from all procedures are presented in this paper. Finally, back analysis using a finite difference method and the published field data are adopted for examination of a developed skin friction equation of micropile in weathered soils respectively.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.165-170
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• 2014

The objective of this study was to make growth and yield models of sowthistle (Ixeris dentata Nakai) by using an expolinear functional equation in a closed-type plant production system. The growth and yield of hydroponically-grown sowthistle were investigated under four different planting distances ($15{\times}10$, $15{\times}15$, $15{\times}20$, and $15{\times}25$ cm). Shoot dry weights per plant was the highest at $15{\times}25$ cm, but was the lowest at $15{\times}10$ cm. Shoot dry weights per area was the highest at $15{\times}15$ cm, but was the lowest at $15{\times}25$ cm. The optimum planting density and planting distance for yield of sowthistle were 44 plants/$m^2$ and $15{\times}15$ cm, respectively. Shoot dry weights per plant and per area were showed as an expolinear type functional equation. A linear relationship between shoot dry and fresh weights was observed to be linear regardless of the planting distance. Crop growth rate, relative growth rate and lost time in an expolinear functional equation showed quadratic function form. Radiation use efficiency of sowthistle was $4.3-6.1g{\cdot}MJ^{-1}$. The measured and estimated shoot dry weights showed a good agreement using days after transplanting as input data. It is concluded that the expolinear growth model can be a useful tool for quantifying the growth and yield of sowthistle in a closed-type plant production system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.863-874
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• 2015

The use of pile reinforcement is considered as one of the most promising techniques for improving load carrying capacity of piles in offshore area. In this study, to consider the horizontal and uplift bearing capacity of submerged breakwater bearing pile, exclusive analysis on load-transfer behaviour of pile was conducted. First of all, check the reinforcing effect from the three-dimensional finite element method, and estimate load transfer curve (ground reaction force). Based on these results, the reinforcing effect was quantified by estimating the coefficients of horizontal and uplift reinforcement of reinforced piles. Load transfer function with consideration of the reinforcing effect was proposed from estimated coefficients. A comparison of the analysis using the proposed load transfer function with three-dimensional finite element analysis has resulted that the proposed load transfer function is displaying good accuracy of predicting behavior of the load transfer between the pile and soil reinforcement. Interpretation of the submerged structure by applying a load transfer function considering the reinforcing effect, has shown that the reinforced pile's shear, bending moment and displacement are less than that of non-reinforced piles, while the subgrade reaction modulus arises greater. Thus, it is expected to be relatively cost effective in terms of design.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.75-86
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• 2002

This paper presents sedimentation and consolidation characteristics of dredged soils mixed with sand materials through the self-weight consolidation tests adopting stepwise filling method. After completely throwing away dredged soils daily by flour kinds of S-C, which is the quantity of sand contained, results fi:om laboratory tests are compared with those from a new method using hyperbolic, which considers stage settling and consolidating characteristics, and those from the existing analyzing method. Liquid limit up to 65% had a large effect on consistency properties. Assuming that the settlement occurred only by clay content of dredged soils, it is shown that the clay void ratio is less than 2 and 4 respectively in case S-C is 0% and 50%. In the applied hyperbolic method, reinitialized curve has a linear behavior of a coefficient of correlation of almost 1, and the coefficient of slope and intercept except fur the specimen with the height of 10cm and 20cm had a tendency to fellow exponent function and a shape of zone settling and dispersing settling. The results computed by the applied hyperbolic method rather than the existing analyzing method coincide with those of laboratory tests. It is shown that the former is more suitable than the latter for the area considering the influence, of sand materials.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.81-88
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• 2006

Delayed luminescence from human hands after illumination by light at different wavelength bands was studied. A delayed luminescence measurement system equipped with photomultiplier tube (PMT), fiber optics and automatic mechanical shutter system was developed. Three spectrum band-pass filters, fer which transmissions are on 350${\~}$450 nm, 450${\~}$550 nm and 550${\~}$650 nm, were used to select irradiation wavelength, and 150W metal-halide lamp was used as an illumination source. Six volunteers put their palms (dorsa) onto the measurement system, and after light illumination, delayed luminescence were measured for 10 minutes. The results show that delayed luminescence after shorter wavelength illumination was higher than that a(ter longer wavelength one. These results indicate the existence of accepters in human skin which can be excited at short wavelengths. Furthermore, each subjects showed different delayed luminescence curve patterns. Reactive oxygen species (ROS) are known to have important roles on delayed luminescence, and this research suggests that ROS concentration can be measured noninvasively with optical methods.