• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.96.1-96.1
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• 2011

Halo coronal mass ejections (HCMEs) are major cause of the geomagnetic storms. To minimize the projection effect by coronagraph observations, we consider two CME cone models: an ice-cream cone model and an asymmetric cone model. These models allow us to determine three dimensional parameters of HCMEs such as radial speed, angular width, and the angle between sky plane and cone axis. In this study, we compare these parameters obtained from both models using 50 well-observed HCMEs from 2001 to 2002. Then we obtain the root mean square error (RMS error) between measured projection speeds and estimated ones for the models. As a result, we find that the radial speeds obtained from the models are well correlated with each other (R=0.89), and the correlation coefficient of angular width is 0.68. The correlation coefficient of the angle between sky plane and cone axis is 0.42, which is much smaller than what is expected. The reason may be due to the fact that the source locations of the asymmetric cone model are assumed to be near the center. The average RMS error of the asymmetric cone model (86.2km/s) is slightly smaller than that of the ice-cream cone model (88.6km/s).

• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.203-209
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• 1982

Commercial ice creams were subjected to chemical analysis and sensory evaluation by trained panel members. Chemical composition of commercial ice creams was not much different among the makers. The average contents of fat, total solid, total protein, milk solids-not-fat, milk lactose and crude ash were 8.53%, 34.18%, 3.43%, 11.02%, 6.17% and 0.84% in Carton, and 6.54%, 34.02%. 3.29%, 10.40%, 5.84% and 0.77% in Cone, respectively. Chemical properties of fat extracted from commercial ice creams were much different among the makers. The average values of acid, saponification, iodine and Reichert-Meissl value were 0.58, 221.88, 19.63 and 29.04 in Carton, and 0.65, 219.45, 18.64 and 28.82 in Cone. According to the results of triangle, ranking and scoring tests for commercial ice creams produced by four makers, significant difference on the sensory quality among four commercial ice cream samples was recognized at over 5 percent level. C and D samples had better sensory quality than A and B in both type of Carton and Cone.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.72.2-72.2
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• 2014

We have made a comparison of three cone models (an asymmetric cone model, an ice-cream cone model, and an elliptical cone model) in terms of space weather application. We found that CME angular widths obtained by three cone models are quite different one another even though their radial velocities are comparable with one another. In this study, we investigate which cone model is proper for halo CME morphology and whether cone model parameters are similar to observations. For this, we look for CMEs which are identified as halo CMEs by one spacecraft and as limb CMEs by the other ones. For this we use SOHO/LASCO and STEREO/SECCHI data during the period from 2010 December to 2011 June when two spacecraft were separated by $90{\pm}10$ degrees. From geometrical parameters of these CMEs such as their front curvature, we classify them into two groups: shallow cone (5 events) and near full-cone (28 events). Noting that the previous cone models are based on flat cone or shallow cone shapes, our results imply that a cone model based on full cone shape should be developed. For further analysis, we are estimating the angular widths of these CMEs near the limb to compare them with those from the cone models. This result shows that the angular widths of the ice-cream cone model are well correlated (CC = 0.81) with those of observations.

• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.210-218
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• 1982

Correlation between the sensory quality characteristics of commercial ice creams and chemical properties of fat extracted from those was studied. The results of evaluation of preference for appearance, flavor, texture and total quality of four commercial ice cream samples by multiple paired comparison test indicated that sample C was the best among samples in both type of carton and cone. There was some correlation between the sensory quality characteristics of commercial ice creams and chemical properties of fat extracted from those in carton, but that was not shown in cone. The results showed that flavor of ice cream in carton and appearance and flavor of ice cream in cone affected total quality, but texture did not.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.5-11
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• 2017

The 19 mm-sized aggregate was produced by melting vinyl waste (waste polyethylene film) generated from vinyl greenhouses in rural areas. It was mixed with As'cone at various weight ratios, and then insulation effect test, tension test after repeated freezing and thawing, ice pull-out strength test and field density test were conducted for the mixtures. These results demonstrated that as the mixing ratio of polyethylene aggregate increased, the insulation effect increased, due to the many pore spaces that existed in the polyethylene aggregate. After repeatedly freezing and thawing As'cone, the tensile strength significantly increased at 2.5% of the polyethylene aggregate content rather than 0% of polyethylene aggregate content but it also slightly decreased at 5% and 10% of polyethylene aggregate content in comparison to 2.5% of its polyethylene aggregate content. As'cone added with polyethylene aggregate by 2.5% resulted in lower ice pull-out strength than that of normal As'cone. As a result of the porosity test for the samples taken at the site, porosity of the As'cone, which added polyethylene aggregate, was smaller than that of the general As'cone.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.28.2-28.2
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• 2011

Coronal Mass Ejections (CMEs) are enormous eruptions of plasma ejected from the Sun into interplanetary space, and mainly responsible for geomagnetic storms and solar energetic particle events. It is very important to infer their direction of propagation, speed and their 3-dimensional configurations in terms of space weather forecast. Two STEREO satellites provide us with 3-dimensional stereoscopic measurements. Using the STEREO observations, we can determine the 3-dimensional structure and radial velocity of the CME. In this study, we applied three different methods to the 2008 April 26 event: (1) Ice cream Cone Model by Xue (2005) using the SOHO/LASCO data, (2) Flux rope model by Thernisien (2009) using the STEREO/SECCHI data, (3) Flux rope model with zero angle using the STEREO/SECCHI data. The last method in which separation angle of flux rope is zero, is similar to the ice cream cone model morphologically. The comparison shows that the radial speeds from three methods are estimated to be about 750km/s and are within ${\pm}120km/s$. We will extend this comparison to other CMEs observed by STEREO and SOHO/LASCO.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.124.1-124.1
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• 2012

We have made a comparison of the WSA-ENLIL CME propagation model with three cone types and an empirical model using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters from Michalek et al. (2007) as well as their associated interplanetary (IP) shocks. For this study we consider three different cone models (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine CME cone parameters (radial velocity, angular width and source location), which are used for input parameters of the WSA-ENLIL CME propagation model. The mean absolute error (MAE) of the arrival times at the Earth for the elliptical cone model is 10 hours, which is about 2 hours smaller than those of the other models. However, this value is still larger than that (8.7 hours) of an empirical model by Kim et al. (2007). We are investigating several possibilities on relatively large errors of the WSA-ENLIL cone model, which may be caused by CME-CME interaction, background solar wind speed, and/or CME density enhancement.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.43.3-43.3
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• 2019

A coronal mass ejection (CME) mass is generally estimated by the total brightness measured from white-light coronagraph observations. The total brightness are determined from the integration of the Thomson scattering by free electrons of solar corona along the line of sight. It is difficult to estimate the masses of halo CMEs due to the projection effect. To solve this issue, we construct a synthetic halo CME with a power-law density distribution (ρ = ρ₀r^-3) based on a full ice-cream cone model using SOHO/LASCO C3 observations. Then we compute a conversion factor from observed CME mass to CME mass for each CME. The final CME mass is determined as their average value of several CME masses above 10 solar radii. Our preliminary analysis for six CMEs show that their CME mass are well determined within the mean absolute relative error in the range of 4 to 15 %.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.49-54
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• 2016

An active layer distributed on surface of an extreme cold region causes a frost heave by repeating the freezing and thawing according to the seasonal temperature change. Since the height of frost heave is greatly affected by the thickness of active layer, an accurate evaluation of the thickness of active layer is necessary for the safe design and construction of the infrastructure in the extreme cold region. In this study, dynamic cone penetrometer, which is miniaturized in-situ penetration device, is applied for the evaluation of active layer depth distribution. As the application tests, two dynamic cone penetration tests were conducted on the study sites located in Solomon and Alaska. In addition, ground temperature variations were obtained. As the results of the application tests, the depth of interface between the active layer and the permafrost was evaluated from the difference in dynamic cone penetration indexes of the active layer and the permafrost, and a layer was detected around the interface considered as an ice lens layer. Also, the interface depths between the above zero and the below zero temperature determined from the ground temperature variations correspond with the interface depths evaluated from the dynamic cone penetration tests. This study demonstrates that the dynamic cone penetrometer may be a useful tool for the evaluation of the active layer in the extreme cold region.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.611-620
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• 2018

For the past decades, the analytic model for distributed surface roughness has been developed to improve the accuracy of the icing simulation code. However, it remains limitations to validate the developed model and determine the empirical parameters due to the absence of the quantitative experimental data which were focused on the surface state. To this end, the experimental study conducted to analyze the ice covered surface state from a micro-perspective. Above all, the tendency of the smooth zone width which occurs near the stagnation point has been quantitatively analyzed. It is observed that the smooth zone width is increased as growing the ambient temperature and freestream velocity. Next, the characteristics of the ice covered surface under rime and glaze ice have been analyzed. For rime ice conditions, ice elements are developed as the opaque circular corn in the opposite direction of freestream. The height and interval of each circular corn are increased as rising the ambient temperature. For glaze ice conditions, numerous lumps of translucent ice can be observed. This is because the beads formed by gravity concentrate and froze on the lower surface.