• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.433-439
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• 2021

In this paper, we propose a method to implement an IoT-based sensor network for each workplace of a shipyard. Here, at the most common welding workplace in shipyards, the shipbuilding blocks are used as a communication medium to transmit information such as the worker's location, welding progress, and working hour to a server using LoRa and powerline communication. To achieve the data communication, inductive couplers and hybrid modems have been manufactured and installed on wire feeders and pin jigs to establish a sensor network. As a result of field test, the proposed system shows a success rate of data transmission and a rate of successful recognition of worker's location of about 98% or more. In addition, the process management system platform can record and display the work process data generated at the field in real time. The proposed system can be a starting point for enhancing the competitiveness of Korean shipbuilding industry through the establishment of a smart shipyard.

• Preventive Nutrition and Food Science
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• v.17 no.1
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• pp.36-45
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• 2012

To produce novel cheese-like fermented soybean, the solid-state fermentation of roasted soybean flour (RSF) was performed using 1.0% inoculum Bacillus subtilis HA and Lactobacillus plantarum, with the initial 60% substrate moisture for 10 hr at $42^{\circ}$, resulting in pH 6.5, 0.82% acidity, 3.5% mucilage, 14.3 unit/g protease activity, 7.6 unit/g fibrinolytic activity, 216 mg% tyrosine content and $1.7{\times}10^{10}$ CFU/g of viable cell counts. After the second lactic acid fermentation with 10~30% skim milk powder, the fermented RSF resulted in an increase in acidity with 1.64~1.99%, tyrosine content with 246~308 mg% and protease activity in the range of 5.2~17.5 unit/g and 0.966 water activity. Viable cell counts as probiotics indicated $1.6{\times}10^8$ CFU/g of B. subtilis and $7.3{\times}10^{10}$ CFU/g of L. plantarum. The firmness of the first fermented RSF with 2,491 $g{\cdot}{\o}mm^{-1}$ greatly decreased to 1,533 $g{\cdot}{\o}mm^{-1}$ in the second fermented RSF, although firmness was slightly increased by adding a higher content of skim milk. The consistency of the second fermented RSF also decreased greatly from 55,640 to 3,264~ 3,998 in the presence of 10~30% skim milk. The effective hydrolysis of soy protein and skim milk protein in the fermented RSF was confirmed. Thus, the second fermented RSF with a sour taste and flavor showed similar textural properties to commercial soft cheese.

• Journal of Korea Foundry Society
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• v.20 no.4
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• pp.240-246
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• 2000

Surface layer properties such as composition, phase, hardness, and oxide layer condition are very important if the main failure mechanism of metals is wear. Generally, stable and dense oxide layers are known to decrease the wear rate of metals by prohibition of metallic junction occurred between bare metals. Addition of Si above 4 wt% to DCI(Ductile Cast Iron) is reported to enhance the significant oxidation resistance by forming the silicon-rich surface layer which inhibits further oxidation. And addition of up to 2 wt% Mo to high Si ductile iron produces significant increases in high temperature tensile strength, creep strength, thermal fatigue resistance and oxidation resistance. High pressure wear characteristics of unalloyed DCI(Ductile cast Iron), 4.46 wt% Si ductile iron, 4.3 wt% Si-0.52 wt% Mo ductile iron were investigated through unlubricated pin-on-disc wear test. Wear test was carried out at speed of 23m/min, under pressure of 3 MPa and 3.3 MPa. Wear surfaces of each specimen were observed by SEM to determine the wear mechanism under high pressure wear condition. Addition of Si 4.46 wt% severely deteriorated wear property of ductile iron compared to unalloyed DCI. But combined addition of Si 4.3 wt%andMo0.52wt%decreasedthefrictioncoefficient(${\mu}$)ofductileironsandremarkablydelayedthemild-severeweartransition.

• Tribology and Lubricants
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• v.35 no.1
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• pp.30-36
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• 2019

The tribological properties of paper-based friction materials are crucial to the performance of a wet clutch system. In this work, the friction and wear characteristics of a paper-based friction material in boundary lubrication state was experimentally investigated using a pin-on-reciprocating tribotester under various normal forces and temperatures. It was found that the wear rate of the friction material increased from $5.8{\times}10^{-6}mm^3/N/cycle$ to $5.5{\times}10^{-5}mm^3/N/cycle$ after 1,700 cycles of testing at $80^{\circ}C$ as normal force increased from 2 N to 7 N. The friction coefficient was also found to increase from 0.135 to 0.155 with increasing normal force from 2 N to 7 N. The increase in contact pressure with increasing normal force may be responsible for these results. In addition, as temperature increased from $20^{\circ}C$ to $80^{\circ}C$, the wear rate of the friction materials increased from $2.0{\times}10^{-5}mm^3/N/cycle$ to $3.6{\times}10^{-5}mm^3/N/cycle$ while the friction coefficient decreased from 0.163 to 0.146. This result may be associated with the decrease in the hardness of friction materials with increasing temperature. Furthermore, plastic deformation on the friction materials was mainly observed after the test. The outcome of this work may be useful to gain a better understanding of the tribological properties of friction materials, and therefore can contribute to the development of friction materials with enhanced performance for wet clutch systems.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.79-94
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• 2009

The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.153-153
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• 2016

Polyoxymethylene copolymer (POM-C) is an attractive and widely used engineering thermoplastic across many industrial sectors owing to outstanding physical, mechanical, self-lubricating and chemical properties. In this research work, the POM-C blocks were irradiated with 1 MeV electron beam energy in five doses (100, 200, 300, 500 and 700 KGy) in vacuum condition at room temperature. The tribological and physico-chemical properties of electron beam irradiated POM-C blocks have been analyzed using Pin on disk tribometer, Raman spectroscopy, SEM-EDS, Optical microscopy, 3D Nano surface profiler system and Contact angle analyzer. Electron beam irradiation at a dose of 100 kGy resulted in a decrease of the friction coefficient and wear loss of POM-C block due to well suited cross-linking, carbonization, free radicals formation and energetic electrons-atoms collisions (physical interaction). It also shows lowest surface roughness and highest water contact angle among all unirradiated and irradiated POM-C blocks. The irradiation doses at 200, 300, 500 and 700 kGy resulted in increase of the friction coefficient as compared to unirradiated POM-C block due to severe chain scission, chemical and physical structural degradation. The electron beam irradiation transferred the wear of unirradiated POM-C block from the abrasive wear, adhesive wear and scraping to mild scraping for the 1 MeV, 100 kGy irradiated POM-C block which is concluded from SEM-EDS and Optical microscopic observations. The degree of improvement for tribological attribute relies on the electron beam irradiation condition (energy and dose rate).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.92-99
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• 2008

The purpose of this study was to evaluate maxillay distraction for the cleft and other patients who were treated with RED $system^{(R)}$(Martin, Tuttlingen Germany). Eleven patients with severe maxillary hypoplasia who were treated between 2002 and 2007 in the Department of Oral and Maxillofacial surgery, Pusan National University Hospital, are reviewed for this study. Their age at the time of surgery ranged from 7 to 22 years(mean age=15.36 years). Distraction was started at 5 days after Le Fort I or III osteotomy at a rate of 1mm per day for 10 to 20days. All patients used the Rigid External Distraction II system. After distraction was completed, a 2 to 3 months period of consolidation was undertaken. The follow-up period ranged from 1 to 6 years. The mean amount of advancement of the maxilla was 14.2mm(A-point). Relapse, VPI, and local infection around the halo pin were the most common complications. In adult patients, the relapse of maxilla ranged from 21% to 35%. In the growing child, postoperative stability of the maxilla was unstable and unpredictable.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.311-317
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• 2015

Phenotypic characterization and body biometric in 13 traits (height at withers, body length, chest girth, paunch girth, ear length, tail length, length of tail up to switch, face length, face width, horn length, circumference of horn at base, distances between pin bone and hip bone) were recorded in 233 adult Gojri buffaloes from Punjab and Himachal Pradesh states of India. Traits were analysed by using varimax rotated principal component analysis (PCA) with Kaiser Normalization to explain body conformation. PCA revealed four components which explained about 70.9% of the total variation. First component described the general body conformation and explained 31.5% of total variation. It was represented by significant positive high loading of height at wither, body length, heart girth, face length and face width. The communality ranged from 0.83 (hip bone distance) to 0.45 (horn length) and unique factors ranged from 0.16 to 0.55 for all these 13 different biometric traits. Present study suggests that first principal component can be used in the evaluation and comparison of body conformation in buffaloes and thus provides an opportunity to distinguish between early and late maturing to adult, based on a small group of biometric traits to explain body conformation in adult buffaloes.

• Archives of Reconstructive Microsurgery
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• v.14 no.1
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• pp.37-41
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• 2005

Purpose: The purpose of this study was to evaluate the effectiveness of internal transport using Ilizarov apparatus with free flap surgery for infected tibial nonunion. Materials and Methods: We reviewed 8 patients of infected tibial nonunion treated with internal transport using Ilizarov apparatus and free flap surgery. Seven of eight patients were available for at least 1 year follow-up. All patients were male. The mean age at the time of the surgery was All fractures were Gustilo's type III B open fracture. The mean length of the bone defect was 8.5 cm. All used flaps for covering the soft tissue defect were free rectus abdominis muscle flap. We evaluated bone and functional results with use of the Paley and Catagni's classification. And we classified the complication with use of the Paley's classification. Results: Acceptable length and solid union of bone was achieved in all cases. The mean size of the bone length was 7.2 cm. The mean healing index was 69.5 days/cm. All but one case needed bone graft at docking site. All flaps were survived. There was no recurrence of infection. According to Paley and Catagni's classification, all cases showed excellent or good results. Complications were pin tract infection in 3 cases, persistent pain in 2 cases and limitation of joint motion in 2 cases. Conclusion: Simultaneous free-tissue transfer and Ilizarov distraction osteogenesis was thought to be an attractive treatment modality for infected nonunion of the tibia.

• Tribology and Lubricants
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• v.33 no.1
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• pp.15-22
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• 2017

Because the running speed of vehicles is increasing and a shorter braking distance is required, high heat-resistant brake pads are needed to satisfy the requirements of customers and car makers. In the near future, hazardous materials such as Cu, Cr, Zn, and Sb will be restricted from use in friction materials. Ceramic composites reinforced by carbon fibers are good candidates for eco-friendly friction materials. In this study, we develop ceramic composite friction materials. The friction materials are composed of carbon fibers, Si, SiC, graphite, and phenol resin and are prepared by hot forming and heat treatment at high temperatures. The density, void ratio, and compressive strength are $1.59-1.66g/cm^3$, 16.6-20, and 70-90 MPa, respectively. Friction and wear tests are performed using a pin-on-plate-type reciprocating friction tester at 25, 100, and $200^{\circ}C$. The counterpart material is a CrMoV steel extracted from a KTX brake disc. Friction coefficient, wear amount, and wear mechanism are measured and examined. We determine that the friction coefficients depend on the temperature and the fluctuation of the friction coefficients is larger at higher temperatures. The amount of wear increases with the surface temperatures of the specimens. The tribological properties of the developed composites are similar to those of a Cu-based sintered friction material. Through this study, it is confirmed that ceramic composite materials can be used as friction materials.