• Journal of Korean Dental Science
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• v.17 no.2
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• pp.53-63
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• 2024

Purpose: To investigate the effects of simultaneous soft and hard tissue augmentation and the addition of polydeoxyribonucleotide (PDRN) on regenerative outcomes. Materials and Methods: In five mongrel dogs, chronic ridge defects were established in both mandibles. Six implants were placed in the mandible, producing buccal dehiscence defects. The implants were randomly allocated to one of the following groups: 1) control: no treatment; 2) GBR: guided bone regeneration (GBR) only; 3) GBR/PDRN: GBR+PDRN application to bone substitute particles; 4) GBR/CTG: GBR+connective tissue grafting (CTG); 5) GBR/VCMX: GBR+soft tissue augmentation using volume stable collagen matrix (VCMX); and 6) group GBR/VCMX/PDRN: GBR+VCMX soaked with PDRN. The healing abutments were connected to the implants to provide additional room for tissue regeneration. Submerged healing was achieved. The animals were euthanized after four months. Histological and histomorphometric analyses were then performed. Results: Healing abutments were gradually exposed during the healing period. Histologically, minimal new bone formation was observed in the dehiscence defects. No specific differences were found between the groups regarding collagen fiber orientation and density in the augmented area. No traces of CTG or VCMX were detected. Histomorphometrically, the mean tissue thickness was greater in the control group than in the other groups above the implant shoulder (IS). Below the IS level, the CTG and PDRN groups exhibited more favorable tissue thickness than the other groups. Conclusion: Failure of submerged healing after tissue augmentation deteriorated the tissue contour. PDRN appears to have a positive effect on soft tissues.

• Composites Research
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• v.37 no.3
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• pp.190-196
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• 2024

The bipolar plate is a crucial element of the vanadium redox flow battery (VRFB) as it serves as both the electrical conduit and the structural support for the cell within the VRFB stack. Although, the graphite material is primarily used for the bipolar plate due to its excellent electrical conductivity, a significant limitation of performance of the VRFB is present due to high interfacial contact resistance (ICR) arises between the electrode and bipolar plate in the cell stack. This study aims to develop an integrated electrode-bipolar plate assembly that will address the limitations of the ICR. The integrated assembly was constructed using a single carbon felt with thermoplastic and thermoset polymers utilizing hot press method. Experimental results verify that the bipolar plate assembly exhibits reduced area specific resistance (ASR) due to the continuous electrical path. Additionally, from the charge/discharge cell test results, the integrated assembly shows improved cell performance. Therefore, the developed integrated electrode-bipolar plate assembly can serve as a substitute for the conventional bipolar plate and electrode assembly.

• Advances in materials Research
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• v.13 no.2
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• pp.115-128
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• 2024

Concrete is the most significant material in the construction industry which is required to construct several facilities like roads, buildings, and bridges etc. which leads to the economic development of a country. But now days, in view of sustainable development and environmental problems, plastic waste management is one of the major environmental issues due to its non-biodegradable nature which allows it to stay in the landfills until they are cleaned up. To overcome all these concerns, plastic waste may be used as a substitute of natural fine and coarse aggregate in concrete and a valuable solution to utilize the plastic items which causes several problems. In order to, present study is focused on the affecting properties of concrete as workability, compressive strength, and tensile strength of concrete with using plastic waste and without using plastic waste. Based on the detailed literature, it was observed that the plastic waste is not affecting the quality and consistency of concrete. However, as the number of PVC particles in the mixture increased, the drying shrinkage values decreased and the inclusion of plastic flakes can mitigate drying shrinkage cracking which leads the higher durability of concrete. Based on the comprehensive literature, it was also observed that the plastic aggregate found to be suitable for low and medium strength concrete. However, the investigation on the application of plastic aggregate in the high strength concrete is found limited. It was concluded that the optimum percentage of the plastic aggregate was found about 20%.

• Journal of Mushroom
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• v.22 no.1
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• pp.17-21
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• 2024

Mushroom-based vegan meat has thus far been used as a food for humans instead of pets. However, based on its texture and nutritional content, it is considered suitable for processing into pet treats. In the present study, we developed a prototype dog chew with a sweetening coating added to a fungal mycelium mat obtained by culturing the Basidiomycetous fungus Trametes orientalis. The palatable coating applied to the mycelium mat by plasticizing the mat with glycerol improved the taste and aroma of the existing mat, and the dog consumed it without difficulty. Future improvements may include a softening process to reduce the chewiness level and a procedure to reduce the crude fiber content. Mycelium-mat-based dog chews, manufactured using eco-friendly materials and processes that are not harmful to the environment are expected to enter the market as eco-friendly alternatives to conventional pet treats. Controlling their physical properties require further study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.137-147
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• 2006

This is an experimental study on the properties and the strength development of concrete using of the oyster shells as a substitute fine aggregate of concrete. For this purpose, the fundamental experiments of the materials and the main factors on it were considered and then the workability and many kinds of strength about the specimens were also studied. As the experimental results, there were strength differences of less than 10% between concrete with oyster shells and normal and the most excellent grain size of oyster shells is 5.0mm and less with taking uniformly and the percentage of practicable substitution of them to fine aggregate about 30%. This paper also represents the relationship equations among many kinds of strength and elastic modulus of concrete with the oyster shells decreased with increase in proportion of oyster shells and curve of it is similar about the percentage of substitution of 10%.

• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.321-327
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• 2018

Blast furnace slag has been actively used as a substitute for cement in the construction field with high value-added through resource recycling research. However, most of the slag cannot find a clear recycling purpose. This is because some slags contain unstable materials and are used for road-use asphalt and embankment, which are low value-added materials. Electric arc furnace reduction slag(ERS) has been reported to contain a large amount of unstable free CaO due to deoxidation and component adjustment. In this study, free CaO of ERS which is generated in Korean steelmakers is quantitatively evaluated by using ethylene glycol method. As a result of free CaO quantitative evaluation of ERS, it was confirmed that there is a big difference according to the location of each field. In addition, ERS generally existed in powder form as undifferentiated characteristics, but it was confirmed that free CaO content was different due to hydration product in aggregate form due to water treatment. In addition, free CaO is an amorphous material and its crystallization characteristics are different due to the influence of temperature when it is cooled. ERS requires a long-term aging period as it contains a lot of free CaO.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.85-92
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• 2002

When the United Nation classified as Korea is the one of the water deficit country. The consensus was made that the water is the one of the precious national resources. Government increases their R/D budget trying to get more clean water bodies. For instances, 'Sustainable Water Resources Development' project is the one of major title in '21 Century Frontier Research project and there are several small research projects are undergoing by the Ministry of Agriculture and KARICO. However, when the environmental preservation issue has been get more emphasis, construction of the Surface Dam met the blockage from the environmentalists due to the problem of the their water buried area. Since the most fitting site for surface dam had been used in the past, some engineer move their focus on modification of the existing Dam's height to enlarge its capacity or dredging the bottom of the reservoir recently However dredging evoke water quality problem in return by accumulated materials at the bottom. Last year the Dong Gang Dam plan has been canceled by environmental problem in water buried area of the reservoir. With the point of this view, ground water gets more focus for the one of the useful alternative for clean water bodies. Underground dam technique which had widely applied once in the early nineteen eighties by the KARICO and attenuated due to engineering insufficiency. The technique is newly studied with the advanced engineering technique. Still groundwater usage rate in Korea is much lower comparing with the advanced countries and has many rooms to develop. Wells, under ground dam and radial collector wells are typical facilities up to now. There is little application in Korea for the Recharge Dam, which had been widely used in the advanced countries. The Recharge Dam is technique to conjunct surface water and groundwater body together, This technique had developed to increase groundwater recharge at the beginning This research is the result of the study on the possibility of the development of the new technology, Groundwater Reservoir' which was modified from Recharge Dam. Groundwater Reservoir is like a deep artificial lakes trenched in hard rock aquifer to get groundwater. The advantage of the Groundwater Reservoir is followings 1) It can be developed at the plains area, not in the deep valley 2) Huge water body can be developed without dam 3) Small buried area comparing surface water dam makes the least environmental effect. 4) Trenching cost can be substitute by the income of the selling rock debris 5) Outfit of the reservoir can be modified to match with the site prospect 6) Rock debris can be used as constructing materials 7) It can be used as groundwater recharge system when the heavy rains comes 8) The reservoir looks like scenery lake with huge clean water bodies.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.636-643
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• 1999

Green-emission intensity of a $Zn_{2-x}Mn_xSiO_4$ phosphor, which is a potential candidate as a green component in PDP device, significantly increases provided that the compound is additionally heat treated at 900$^{\circ}C$ after solid state reaction at 1300$^{\circ}C$. In order to verify origin of such an intensity enhancement after the additional heat treatment in association with the electronic and local structural change at around Mn ions, the Mn K-edge X-ray absorption spectra were recorded. From the analyses of the preedge peak corresponding to $1s{\rightarrow}3d$ bound state transition and XANES spectrum, it is known that most Mn ions are in +2 oxidation state and substitute Zn ion site regardless of the thermal treatment. In addition, EXAFS analyses revealed that Mn ions formed $MnO_4$ tetrahedra with the Mn-O bond length shortened by 0.01${\AA}$ and with reduced Debye-Waller factor in the thermally treated sample.

• Journal of Periodontal and Implant Science
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• v.27 no.2
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• pp.363-377
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• 1997

The main goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal diseases. Although conventional forms of periodontal therapy show sound clinical results, the healing results in long junctional epithelium. There have been numerous materials and surgical techniques developed for new attachment and bone regeneration. Bone grafts can be catagorized into: autografts, allografts, xenografts and bone substitutes. Synthetic bone substitute materials include hydroxyapatite, tricalcium phosphate, calcium carbonate, and Plaster of Paris. Calcium sulfate has found its use in dental practice for the last 30 years. Recent animal studies suggest that periodontal regeneration in 3 wall intrabony defect may be enhanced by the presence of calcium sulfate. And it is well known that 2 wall & 1 wall defect have less osteogenic potential, So we need to study the effect of calcium sulfate in 1 wall intrabony defect in dogs. The present study evaluates the effects of calcium sulfate on the epithelial migration, alveolar bone regeneration and cementum formation in intrabony defects of dogs. Four millimeter-deep one-wall intrabony defects were surgically created in the mesial aspect of anterior teeth and mesial & distal aspects of premolars. The test group received calcium sulfate grafts with a flap procedure. The control underwent flap procedure only. Histologic analysis following 8 weeks of healing revealed the following results: 1. The lengths of junctional epithelium were: 2.52mm in the control, and 1.89mm in the test group. There was no statistical significance between the two groups. 2. Alveolar bone formation were: 0.61mm in the control, and 1.88mm in the test group. There was a statistically significant difference between the two groups (p<0.05). 3. Cementum formations were: l.lmm in the control, and 2.46mm in the test group. There was a statistically significant difference between the two groups (p<0.05). 4. The length of CT adhesion were: O.97mm in the control, and 0.17mm in the test group. There was no statistically significant differences between the two groups These results suggest that the use of calcium sulfate in intrabony defects has little effect on junctional epithelium migration, but has significant effects on new bone and new cementum formations.

• Microbiology and Biotechnology Letters
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• v.1 no.2
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• pp.79-87
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• 1973

The superior materials for substitution of bean and red pepper paste were selected through the examination of chemical compositions and the function. The following results were obtained. (1) The enzyme activities were higher in the process of koji manufacturing for brewing bean paste and red pepper paste in barley koji and in corn powder koji, but those of wheat koji were inferior (2) Corn powder was proved as the most excellent substitute, because its components and functioning were the best. (3) In the production of the paste the use of corn powder and bean with equal amount was proved as good as those product of the traditional way of the brewing. (4) By using the corn powder, the production cost can be cut down to 25％ in the production of bean paste, and to 23％ in the production of red pepper paste, comparing with those of traditional brewing products