• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.143-148
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• 2016

The aim of research is inducing the optimum proportion of fly ash(FA) and blast furnace slag(BS) for ternary cement. In this research, hence, the fundamental properties of mortar mixtures were evaluated depending on various proportion of FA and BS. The results of the experiment, within the scope of the study, obtained the following conclusions. Flow of the mixtures was increased with addition of binary supplementary cementitious material(SCM), and especially, portion of FA. The air content of the mixtures was increased with addition of binary SCMs, while it was decreased with increased FA content. In the case of unit mass, increased value was obtained due to the increased air content within 25 to 45% of binary SCM content, while it was increased within 65 to 100% of binary SCM up to only 20% of FA content and decreased more than 20% of FA because of the low density of FA. The setting time of the mixtures was delayed with addition of binary SCM and FA. In the case of compressive strength, at 91-day age, the highest value was obtained with 25 and 45% of binary SCM with the proportion of FA to BS of 40 to 60. Therefore, based on the compressive strength, it is considered that the binary SCM content of 25 and 45% with the proportion of FA to BS of 2 : 3 is the most favorable conditions in this research scope.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.88-94
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• 2011

To make recycling aggregate, quantity of fine particles increase due to multi-crushing. Though this particles were mixed with recycling aggregate, those have to be disparted from aggregate in the high quality recycling aggregate, because of the cause of low quality. Considering reactivity, fine particles is better than coarse one. Therefore, it needs to develop suitable usage. We try to make cement extruding material by using the fine particles from concrete recycling, as a silicious replacement. Test results are as follows ; 1) Waste concrete powder has major ingredients such as $SiO_2$ and CaO, its density is $2.45g/cm^3$ being similar to silica powder, its diameter is range 13 to $141{\mu}m$. 2) Considering to strength properties according to particle size, specimen was made using small particles is higher strength than large one. 3) Despite of exception in the autoclaved curing, when the replacement of waste fine particle increase, strength of extruding panel shows almost same level.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.423-435
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• 1995

The purpose of this study was to observe the effect of TGF-βl, which promotes differentiation and proliferation of osteoblasts, on bone regeneration. Experimental bone defects that measured 3 mm in diameter were created on the mandibles of guinea pig by removal of bone with the use of trephine burs. In one side of mandibular body, the experimental groups, bone defects were grafted with Biogran(Orthovita Co., U.S.A) and TGF-β1(R&D System Co., U.SA). In the remaining side of the mandiblar body, the control groups, bone defects were grafted with only Biogran. Guinea pigs in the control and experimental groups were serially terminated by fours on the 3 days, the 1 week, the 2 weeks, the 3 weeks, and the 4 weeks after experiment, and both sides of the mandibular bodies were removed and fixed with 10％ neutral formalin. They were decalcified and embedded in paraffin as using the usual method. The specimen sectioned and stained with hematoxylin and eosin. Also, they were radiographed with a soft X -ray apparatus. The obtained results were as follows; 1. Hemorrhagic condition, observed in the granulation tissues, disappeared on the 1 week after experiment in both groups, and more prominent in the experimental group. The granulation tissues of the experimental group had larger number of cells than those of the control group. 2. Osteoblastic differentiation in the margin of grafted material and adjacent bone was observed on the 1 week after experiment in both groups. Also, bone formation was observed in immature form on the 1 week after experiment. and more prominent in the experimental group. 3. In the polarizing microscopic examination, bone matrix was very loose on the 1 week after experiment, but increase in density with time, and more prominent in the experimental group. 4. In the microradiographic examination, newly formed bone was observed in the experimental group on the 2 weeks after experiment, and this was observed earlier than in the control group. Newly formed bone was increased with time and defected area was markedly decreased on the 4 weeks after experiment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.465-472
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• 2017

In this study, tuna sawdust was added to extruded meat analog in order to develop a meat analog with high quality. Addition of tuna sawdust has merit for utilizing a byproduct from poultry processing. Physicochemical characteristics were examined through the extrusion cooking process. The basic mixture of sample mixed with 65% deffated soy flour 25% isolated soy protein, and 10% corn starch was setup as the raw material. Three kinds of samples were made in total by addition of 15% and 30% tuna sawdust to this mixture. The extrusion process had a screw speed of 250 rpm, die temperature of $140^{\circ}C$, and moisture content of 50%. As addition of tuna sawdust increased, breaking strength and density decreased, specific length increased, and integrity and water holding capacity decreased. Likewise, nitrogen solubility index and protein digestibility decreased as addition of tuna sawdust increased. DPPH radical scavenging activity increased as addition of tuna sawdust addition, whereas it decreased as storage period increased to 30 or 60 days. The value of rancidity decreased as addition of tuna sawdust increased. However, 60 days later, radical scavenging activity increased more or less, and a significant difference was detected 150 days later. In conclusion, addition of tuna sawdust increased soft texture, and nutrition of the basic mixture sample. The process promoting functionality such as improvement of antioxidant function was confirmed through this study.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.389-394
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• 2016

Background: Tetrahedral-mesh geometries can be used in the MCNP code, but the MCNP code accepts only the geometry in the Abaqus input file format; hence, the existing tetrahedral-mesh models first need to be converted to the Abacus input file format to be used in the MCNP code. In the present study, we developed a simple but useful computer program, TET2MCNP, for converting TetGen-generated tetrahedral-mesh models to the Abacus input file format. Materials and Methods: TET2MCNP is written in C++ and contains two components: one for converting a TetGen output file to the Abacus input file and the other for the reverse conversion process. The TET2MCP program also produces an MCNP input file. Further, the program provides some MCNP-specific functions: the maximum number of elements (i.e., tetrahedrons) per part can be limited, and the material density of each element can be transferred to the MCNP input file. Results and Discussion: To test the developed program, two tetrahedral-mesh models were generated using TetGen and converted to the Abaqus input file format using TET2MCNP. Subsequently, the converted files were used in the MCNP code to calculate the object- and organ-averaged absorbed dose in the sphere and phantom, respectively. The results show that the converted models provide, within statistical uncertainties, identical dose values to those obtained using the PHITS code, which uses the original tetrahedral-mesh models produced by the TetGen program. The results show that the developed program can successfully convert TetGen tetrahedral-mesh models to Abacus input files. Conclusion: In the present study, we have developed a computer program, TET2MCNP, which can be used to convert TetGen-generated tetrahedral-mesh models to the Abaqus input file format for use in the MCNP code. We believe this program will be used by many MCNP users for implementing complex tetrahedral-mesh models, including computational human phantoms, in the MCNP code.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.93-98
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• 2005

The crystal growth of calcite at a low temperature range was carried out by the hydrothermal method using amorphous calcium carbonate which has excellent solubility in water. Amorphous calcium carbonate was prepared by the wet chemical reaction of a stoichiometric mixture of $CaCl_2\;and\;Na_2CO_3$. An important factor was the reaction temperature and time taken in preparation of the amorphous calcium carbonate. From the solubility results calculated by the weight loss method, $NH_4NO_3$ solutions were found to be the most promising solvents to grow calcite single crystals. The hydrothermal conditions for high growth rates of calcite single crystals were as follows: starting material: amorphous calcium carbonate, solvent: 0.01 m $NH_4NO_3$, temperature: $180^{\circ}C$, duration: 30 days. And properties of calcite single crystals were follows: dislocation density: $10^6{\sim}10cm^{-2}$, UV-visible transmittance: about 80% from 190 to 400 nm and birefringence: $0.17{\sim}0.18$. Also, it can be known from the FT-IR results that the absorption peak by injection of $HCO_3^-\;and\;OH^-$ ions was not shown.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.364-371
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• 2015

For the cost down of polymer concrete, It is very important to reduce the use amount of polymer binder, which occupies most of the production cost of polymer concrete. Fly ash and atomizing reduction steel slag are spherical materials obtained from industrial by-products. Spherical atomizing reduction steel slag was manufactured using steel slag from reduction process of ladle furnace by atomizing technology. To investigate the physical properties of polymer concrete, polymer concrete specimens were prepared with the various proportions of polymer binder and replacement ratios of atomizing steel slag. Results showed that compressive and flexural strengths of the specimens were remarkably increased with the addition amount of polymer binder and the replacement ratios of atomizing steel slag. In the hot water resistance test, compressive strength, flexural strength, bulk density and average pore diameter decreased but total pore volume and pore diameter increased. We found that polymer concrete developed in this study reduced the amount of polymer binder by 18.2% compared to the conventional product because of the remarkable improvement of workability of polymer concrete using spherical fly ash and atomizing reduction steel slag instead of calcium carbonate (filler) and river sand (fine aggregate).

• Advanced Composite Materials
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• v.17 no.1
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• pp.25-40
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• 2008

The research and development in soundproof materials for preventing noise have attracted great attention due to their social impact. Noise insulation materials are especially important in the field of soundproofing. Since the insulation ability of most materials follows a mass rule, the heavy weight materials like concrete, lead and steel board are mainly used in the current noise insulation materials. To overcome some weak points in these materials, fiber reinforced composite materials with lightweight and other high performance characteristics are now being used. In this paper, innovative insulation sheet materials with carbon and/or glass fabrics and nano-silica hybrid PU resin are developed. The parameters related to sound performance, such as materials and fabric texture in base fabric, hybrid method of resin, size of silica particle and so on, are investigated. At the same time, the wave analysis code (PZFlex) is used to simulate some of experimental results. As a result, it is found that both bundle density and fabric texture in the base fabrics play an important role on the soundproof performance. Compared with the effect of base fabrics, the transmission loss in sheet materials increased more than 10 dB even though the thickness of the sample was only about 0.7 mm. The results show different values of transmission loss factor when the diameters of silica particles in coating materials changed. It is understood that the effect of the soundproof performance is different due to the change of hybrid method and the size of silica particles. Fillers occupying appropriate positions and with optimum size may achieve a better effect in soundproof performance. The effect of the particle content on the soundproof performance is confirmed, but there is a limit for the addition of the fillers. The optimization of silica content for the improvement of the sound insulation effect is important. It is observed that nano-particles will have better effect on the high soundproof performance. The sound insulation effect has been understood through a comparison between the experimental and analytical results. It is confirmed that the time-domain finite wave analysis (PZFlex) is effective for the prediction and design of soundproof performance materials. Both experimental and analytical results indicate that the developed materials have advantages in lightweight, flexibility, other mechanical properties and excellent soundproof performance.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.322-331
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• 2007

In this study, electrical resistivity tomography (ERT) were conducted to find the mineralized zone at the Geumpung mine in Dojeon-ri, Susan-myeon, Jecheon-si, Chungcheongbuk-do. The deviation of the inclined borehole was measured to obtain the exact positions of the electrodes for correcting apparent resistivity values from ERT. Geophysical loggings such as resistivity and natural gamma were conducted to obtain the properties of the material near the borehole. Measurements of the physical properties of the cores, such as porosity, water content, density, susceptibility, resistivity were performed to analyze the correlation between physical properties and resistivity. Grade analysis for core sample was also conducted to identify relationship between grade and resistivity. Rock property analysis shows that the resistivity is more dominated by susceptibility and grade than by porosity and water content in the mineralized zone. The results of ERT are well consistent with geophysical logging data and geologic column. So ERT is powerful method to identify conductive mineralized zone.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.274-287
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• 2000

The use of dental implants has increased tremendously in recent years and is expected to increase even more in the future. The successful outcome of any implant procedure is surely dependent on interrelationship of the various components of an equation that includes biocompatibility of implant material, macroscopic and microscopic nature of the implant surface, the status of implant bed, surgical technique, undisturbed healing phase and subsequent prosthetic design and long-term loading phase. The purpose of this study was to clarify the effects of adrenalectomy on the osseointegration of pure titanium implants. Seventy rats, 11 weeks of age, were divided into two groups : an adrenalectomized group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm) was placed into left tibia of 70 rats, 35 in control group and 35 in the experimental group. The rats were sacrificed at different time interval (1, 2, 3, 4, 6, 8, and 12 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with fibronectin and CD44 antibody. The results obtained from this study were as follows: 1. Histopathogically, findings, newly formed bone was seen at 3 weeks control group and became lamellar bone at 12 weeks. At 6 weeks, lipocytes were observed in bone marrow space. Thickness of regenerated trabecular bone increased till 6 weeks after then, that decreased gradually. 2. By histomorphometric analysis, marrow bone density and contact ratio of marrow bone to implant decreased significantly from 8 to 12 weeks in experimental group compared to control group and also total bone to implant contact ratio decreased significantly from 4 to 12 weeks in experimental group compared to control group. 3. Fibronectin immunoreactivity was very strong at 3 and 4 weeks control group. And after that reduced gradually. But it was continuously strong from 1 to 12 weeks experimental group. 4. CD44 immunoreactivity was very strong in the newly formed osteoblasts at 3 and 4 weeks control group. But it reacted minimally later. However, it reacted continuously strong from 3 to 12 weeks experimental group. From these results, bone to implant contact ratio decreased gradually from 4 weeks in adrenalectomized group compared to control group. CD44 and fibronectin immunoreactivities were strong at all times in adrenalectomized rats. Therefore, it could be stated that immature bone remained continuously for a long time and not readily proceeded into mature status.