• Journal of Power System Engineering
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• v.17 no.3
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• pp.44-49
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• 2013

The refrigerating system are high efficiency and comfortable due to the automation of the system as well as enhance energy saving are contributing to driving system. Previous study the rotational frequency of the compressor was confined to the fixed condition have changed load of evaporator and condenser related about the refrigerator performance characteristic according to the evaporation load and condensation load change tries to be analyze through the experiment. The useful data for the economic driving of the freezing apparatus tries to be drawn. Consequently, it confirmed that refrigerant in the compressor overheated and as the evaporation load increased the specific volume was increased and the coolant circulation rate decreased. In confirmed that condensation load increased the compression ratio and discharge gas temperature increased. It reduced the low-temperature efficiency and condensation calorie and the quality factor was decreased.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1424-1428
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• 2003

Present investigation was conducted to determine the post-thaw sperm motility and acrosomal damage of filtered and non-filtered frozen semen of Murrah buffalo bulls. Twenty semen ejaculates (from four Murrah buffalo bulls collected at weekly interval) were diluted in Tris egg yolk glycerol extender and divided into two parts. One was filtered through sephadex G-100 column and the other portion was kept as such (non-filtered). Both fractions were frozen in liquid nitrogen ($-196^{\circ}C$) by the standard method developed in the laboratory. After 24 h of freezing, non-filtered and filtered semen samples were thawed at $37^{\circ}C$ for 1 min. These samples were incubated at $37^{\circ}C$ in a water both. The different seminal characteristics i.e. percent progressive sperm motility, live and abnormal spermatozoa and spermatozoa with damaged acrosome were assessed at hourly interval till they remained motile. The filtered frozen and thawed semen showed significantly (p<0.05) high sperm viability and acrosomal integrity as compared to non-filtered semen.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.145-151
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• 2002

This paper is results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), Improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines m sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand plies was found in the range of 2.0 - 2.5 times of pile diameter.

• Journal of radiological science and technology
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• v.19 no.2
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• pp.79-83
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• 1996

The thermoluminescence(TL) response in changing annealing condition, triboluminescence, and darkroom temperature for $Mg_2SiO_4$:Tb phosphor are examined. The experimental results are summerized as follows : 1. The uniformity of TL intensity is better In the disinfected $Mg_2SiO_4$ : Tb than in contaminated one. 2. The triboluminescence of $Mg_2SiO_4$ : Tb is almost not detected even if numbers of $Mg_2SiO_4$ : Tb falling are increased. 3. The fading effect of $Mg_2SiO_4$ : Tb is scarcely affected by freezing room. The followings are resulted from the study. The disinfected $Mg_2SiO_4$ : Tb phosphor should be used in the dose measurement and the immediate reading for $Mg_2SiO_4$ : Tb after exposure is better. And if the reading is not immediately taken, a law darkroom temperature for $Mg_2SiO_4$ : Tb storage is recommended.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.117-124
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• 2007

Focused on the material-related aspect for enhancing the durability of concrete, the present study analyzed the effect of glycol ether admixture, which is a chemical admixture that can compact the structure of concrete by entraining air inside the concrete, on the basic physical properties and durability characteristic of the concrete. In analyzing the results of experiment, we examined the basic physical properties and durability characteristic of concrete according to addition rate based on OPC and selected the optimal addition rate. In addition, with the optimal addition rate, we added glycol ether admixture to concrete, which contained fly ash used as binder and high-performance water reducing agent for reducing the unit quantity, and examined changes in the characteristics of the concrete. According to the result, the optimal addition rate of glycol ether admixture was 3% of the unit quantity of cement, and the addition of binder and chemical admixture did not have a significant effect on unhardened concrete but reduced the air content. In addition, concrete showed resistance performance of around 30% to carbonation and around 40% to drying shrinkage. In addition, as for resistance to freezing and thawing, the relative dynamic modulus of elasticity was over around 85% through atmospheric curing. These performances prove the effect.

• Korean Journal of Medicinal Crop Science
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• v.23 no.6
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• pp.431-438
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• 2015

Background : This study was conducted to determine out the effect of storage temperature on the quality of fresh ginseng (Panax ginseng C. A. Meyer) during distribution. Methods and Results : Fresh ginseng was washed, packed in $30{\mu}m$ low density polyethylene (LDPE) film, then stored at 0, -2 and $-4^{\circ}C$. After 4 weeks of storage, ginseng was then stored at $5^{\circ}C$, as a simulation of the distribution process. Ginseng stored at $-4^{\circ}C$ showed higher respiration rate, ethylene production and electrolyte conductivity during the distribution phase than those stored at 0 and $-2^{\circ}C$. Decay and browning rate rapidly increased following 3 weeks of distribution in samples stored $-4^{\circ}C$. However ginseng stored $-2^{\circ}C$, which is below freezing point, for 4 weeks did not show the physiological change or quality deterioration. Ginsenoside contents decreased during storage for all plant, but did not differ significantly between storage temperatures. Conclusions : Storage at temperatures below $-2^{\circ}C$ can negatively affect respiratory characteristics and electrolyte leakage and increase quality deterioration and decay rates during distribution.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.3
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• pp.41-49
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• 2015

The repair of manhole raise has been caused much construction times and disruption of traffic flow, serious environmental pollution from crushed construction wastes, and budget waste due to the repeated repair construction works. In order to overcome such problems, we have developed the new manhole repairing composite structures by using a glass fiber-reinforced polymer (GFRP) pipe, which can raise manhole to the regular height of the overlayed road pavement with rapid construction and minimum traffic jams. This environmental-friendly technology is method completed by the methyl methacrylate monomer (MMA) double wide flanged GFRP pipe composite structures in order to raise manhole to the regular height. In this paper, two kinds of the compressive strength tests of MMA mortar composites were conducted and evaluated by a general compressive strength test, and compressive strength test after freezing-thawing resistance test. It was found that this MMA mortar composites will be used for the application of the double wide flanged GFRP pipe composite structures.

• Journal of Powder Materials
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• v.21 no.5
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• pp.366-370
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• 2014

The present study demonstrates the effect of solidification condition on the pore structure in freeze drying process using the slurries of CuO/sublimable vehicles. Camphene and Camphor-45 wt% naphthalene based slurries with 14 vol% CuO powder were frozen into a mold at $-25^{\circ}C$, followed by sublimation at room temperature. The green bodies were hydrogen-reduced and sintered at $500^{\circ}C$ for 1 h. The porous Cu specimen, frozen the CuO/camphene slurry into the heated mold of the upper part, showed large pores with unidirectional pore channels and small pores in their internal wall. Also, it was observed that the size of large pores was decreasing near the bottom part of specimen. The change of pore structure depending on the freezing condition was explained by the nucleation behavior of camphene crystals and rearrangement of solid powders during solidification. In case of porous Cu prepared from CuO/Camphor-naphthalene system, the pore structure exhibited plate shape as a replica of the original structure of crystallized vehicles with hypereutectic composition.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.76-93
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• 1997

Activated carbon is widely used for the treatment of water, wastewater and other liquid wastes. Biological activated carbon (BAC) process is water and wastewater treatment process developed in the 1970's. In addition to activated carbon adsorption, biodegradation organic pollutants occurs in the BAC bed where a large amount of aerobic biomass grows. This results in a long operation time of the carbon before having to be regenerated and thus a low treatment cost. Although the BAC process has been widely used, its mechanisms have not been well understood, especially the relationship between biodegradation and carbon adsorption, whether these two reactions can promote each other or whether they just simultaneously exist in the BAC bed. Also, the phenomenon of bioregeneration has been confused that previously occupied adsorption sites appear to be made available through the actions of microorganisms. And that, because biological process is influenced by low temperature, the mechanism of the BAC process is also effected by temperature variation in our country of winter temperature near the freezing point. Therefore, the objective of this study examines closely the mechanism of the BAC process by temperature variation using phenol as substrate. From this study, biological activated carbon is good substrate removal better than non adsorbing materials (charcoal, sand) as temperature variation, especially low temperature(near $5^{\circ}C$).

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.21-22
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• 2009

This paper presents the results of an experimental study on flexural behavior and cracking process of concrete beams subjected to cycles of freezing and thawing after patch-repaired with strain-hardening cement composites (SHCCs). The SHCCs were reinforced with hybrid 0.75% PVA and 0.75% PE fibers. Experimental testing of concrete beams patch-repaired with SHCCs revealed that the SHCC patch-repair system without freeze thaw (FT) exposure showed average 3.31 times increased load carrying capacity and for beams exposed to 300 FT cycles, load carrying capacity increased up to 2.42 times. Cracking damage of SHCC patch-repaired beams mitigated compared to plain concrete beams but this trend decreased under FT exposure.