• Textile Coloration and Finishing
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• v.29 no.1
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• pp.37-44
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• 2017

An issue of major concern in the utilization of laminated composites based epoxy resin is associated with the occurrence of delaminations or interlaminar cracks, which may be related to manufacturing defects or are induced in service by low-velocity impacts. A strong interfacial filament/brittle epoxy resin bonding can, however, be combined with the high fracture toughness of weak interfacial bonding, when the filaments are arranged to have alternate sections of shear stress. To improve this drawback of the epoxy resin, UV-thermal dual curable resin were developed. This paper presents UV-thermal dual curable resin which were prepared using epoxy acrylate oligomer, photoinitiators, a thermal-curing agent and thermoset epoxy resin. The UV curing behaviors and characteristics of UV-thermal dual curable epoxy resin were investigated using Photo-DSC, DMA and FTIR-ATR spectroscopy. The mechanical properties of UV-thermal dual curable epoxy resin impregnated CF prepreg by UV curable resin content were measured with Tensile, Flextural, ILSS and Sharpy impact test. The obtained results showed that UV curable resin content improves the epoxy toughness.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.27-36
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• 2011

The Dual Contouring method has an advantage over the primal polygonization methods like the Marching Cube method in terms of better expression of sharp features. In this paper, the Dual Contouring method is implemented in Spherical coordinates, not the Cartesian ones to examine some characteristics. For this purpose, our octree is defined in Spherical coordinates, which is called "S-Octree". Among some characteristics, the proposed Dual Contouring method in the S-Octree tends to produce less vertices at the same octree level. In particular, for any surface models close to surface sphere, the generated mesh surfaces are smoother and more detailed than those of the Cartesian Dual Contouring approach for specific applications including mesh compression where available geometric information is quite limited.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.551-558
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• 2009

Most of clustering schemes focusing on the energy efficiency have only a cluster head in each cluster, thus the energy consumption of cluster head in a cluster can rapidly increase. To reduce the energy consumption, recently, the dual-layered clustering which is separated a cluster ranges into two parts, i.e., data aggregation layer and data transmission layer, based on a sensor equipped with geographical positioning system (GPS), was proposed. However, the logical regions existing within the dual-layered clustering range can not distinguish efficiently. This scheme leads to many messages collision and transmission delay among member nodes. In this paper, to solve these problems, we propose a separated dual-layered routing scheme using the position information and the cluster radius. Proposed scheme clearly distinguish the dual-layered clustering range and gets the balanced number of member nodes in each cluster. Therefore, the proposed routing scheme could prolong the overall network life time about 10% compared to the previous two layered clustering scheme and LEACH.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.1
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• pp.1-9
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• 2013

PURPOSE: This study compared the effects of dual motor task training and simple task training on the balance of subacute stroke patients. METHODS: A total of 23 subacute stroke patients participated in the study. The subjects were allocated randomly to two groups: an experimental group and a control group. Both groups received conventional treatment for 50 minutes, 5 times per week for 6 weeks. In addition, the experimental group stacked blocks, moved catch cups, and moved rings while standing and gait. To evaluate the effects of the exercises, subjects were evaluated by using the balance system and the timed get up and go test(TUG) for balance measurement. The data was analyzed using a paired t-test and independent t-test to determine the statistical significance. RESULTS: The experimental group showed a significant decrease on the medial-lateral and anterior-posterior stability index compared to the control group (p<.05) for the simple task and a significant decrease on the medial-lateral and anterior-posterior stability index compared to the control group for the dual task. In addition, the experimental group showed a significant increase in TUG time compared to the control group (p<.05). CONCLUSION: These results support the perceived benefits of dual motor task training to augment the balance of subacute stroke patients. Therefore, dual motor task training is recommended for subacute stroke patients.

• Journal of Families and Better Life
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• v.31 no.4
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• pp.145-164
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• 2013

This study analyzed qualitative data to examine the attitude toward the conditions of and the barriers to the work- family balance among unmarried workers. The data was drawn from 5 focus groups consisting of 4 workers each. The 20 participants, aged 21 through 38, were interviewed in mini groups composed of 2 male workers and 2 female workers each. The research depicts four main themes about their work-family balance: the image of a dual-earner family, women's market labor, housework, and the ideal conditions of a dual-earner family. This research concluded that unmarried workers desperately want to be part of a dual earning family for economic survival. However, they also know that it would be very difficult to make ends meet and to live as dual-earner families because of the lack of a proper social support system. However, most of them believe that they must solve these problems on their own, and they do not expect to receive help from systematic public policies. They think that they should find solutions by rearranging the role divisions between the husband and the wife or by asking for help from their parents or other relatives. The only assistance they expect from the government are reliable child care facilities and governmental incentives to promote stimulate the family-friendly workplace.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.54-58
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• 2007

The trailers with electronically controlled diesel engine was converted to dual fuel engine system. To estimate economical efficiency, test vehicles have been operated on a certain driving route repeatedly. Fuel economy, mximum driving distance per refueling and driveability are examined on the road including a free way. Developed vehicle can be operated over 500 km with dual Hel and shows 85% of diesel substitution ratio. Driveability is similar with but passing acceleration. It will be improved by calibration process. Test engine was set up for investigating power output, thermal efficiency and emission. ND 13-mode tests were performed for the test cycle. The emission result of dual fuel meets K2006 regulation and the engine performance of dual fuel engine was equivalent to the performance of diesel engine.

• Structural Engineering and Mechanics
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• v.6 no.2
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• pp.125-141
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• 1998

Recent test results of steel moment connections repaired with a haunch on the bottom side of the beam have been shown to be a very promising solution to enhancing the seismic performance of steel moment-resisting frames. Yet, little is known about the effects of using such a repair scheme on the global seismic response of structures. When haunches are incorporated in a steel moment frame, the response prediction is complicated by the presence of "dual" panel zones. To investigate the effects of a repair on seismic performance, a case study was conducted for a 13-story steel frame damaged during the 1994 Northridge earthquake. It was assumed that only those locations with reported damage would be repaired with haunches. A new analytical modeling technique for the dual panel zone developed by the author was incorporated in the analysis. Modeling the dual panel zone was among the most significant consideration in the analyses. Both the inelastic static and dynamic analyses did not indicate detrimental side effects resulting from the repair. As a result of the increased strength in dual panel zones, yielding in these locations were eliminated and larger plastic rotation demand occurred in the beams next to the shallow end of the haunches. Nevertheless, the beam plastic rotation demand produced by the Sylmar record of 1994 Northridge earthquake was still limited to 0.017 radians. The repair resulted in a minor increase in earthquake energy input. In the original structure, the panel zones should dissipate about 80% (for the Oxnard record) and 70% (for the Sylmar record) of the absorbed energy, assuming no brittle failure of moment connections. After repair, the energy dissipated in the panel zones and beams were about equal.

• The Journal of Advanced Prosthodontics
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• v.7 no.6
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• pp.460-467
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• 2015

PURPOSE. The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. MATERIALS AND METHODS. Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The three-dimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For two-dimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. RESULTS. In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (P<.05). In three-dimensional analysis, the biggest difference was seen between intraoral scanning and dual-arch impression and the smallest difference was seen between dual-arch and full-arch impression. CONCLUSION. The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P<.05). The second premolar showed significantly bigger three-dimensional deviations than the second molar in the three-dimensional deviations (P>.05).

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.3
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• pp.159-172
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• 2015

Treatment of polymicrobial infected musculoskeletal defects continues to be a challenge in orthopaedics. This research investigated single and dual-delivery of two antibiotics, vancomycin and amikacin, targeting different classes of microorganism from a biodegradable calcium sulfate-chitosan-nHA microsphere composite scaffold. The addition of chitosan-nHA was included to provide additional structure for cellular attachment and as a secondary drug-loading device. All scaffolds exhibited an initial burst of antibiotics, but groups containing chitosan reduced the burst for amikacin at 1hr by 50%, and vancomycin by 14-25% over the first 2 days. Extended elution was present in groups containing chitosan; amikacin was above MIC ($2-4{\mu}g/mL$, Pseudomonas aeruginosa) for 7-42 days and vancomycin was above MIC ($0.5-1{\mu}g/mL$ Staphylococcus aureus) for 42 days. The antibiotic activity of the eluates was tested against S. aureus and P. aeruginosa. The elution from the dual-loaded scaffold was most effective against S. aureus (bacteriostatic 34 days and bactericidal 27 days), compared to vancomycin-loaded scaffolds (bacteriostatic and bactericidal 14 days). The dual- and amikacin-loaded scaffolds were effective against P. aeruginosa, but eluates exhibited very short antibacterial properties; only 24 hours bacteriostatic and 1-5 hours bactericidal activity. For all groups, vancomycin recovery was near 100% whereas the amikacin recovery was 41%. In conclusion, in the presence of chitosan-nHA microspheres, the dual-antibiotic loaded scaffold was able to sustain an extended vancomycin elution longer than individually loaded scaffolds. The composite scaffold shows promise as a dual-drug delivery system for infected orthopaedic wounds and overcomes some deficits of other dual-delivery systems by extending the antibiotic release.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.192-204
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• 2018

In this study, a 3D CFD analysis method for the combustion process was established for a low calorific value syngas-diesel dual-fuel engine operating under very lean fuel-air mixture condition. Also, the accuracy of computational analysis was evaluated by comparing the experimental results with the computed ones. To simulate the combustion for the dual-fuel engine, a new dual-fuel chemical kinetics set was used that was constituted by merging two verified chemical kinetic sets: n-heptane (173 species) for diesel and Gri-mech 3.0 (53 species) for syngas. For dual-fuel mode operations, the early stage of combustion was dominated by the fuel burning inside or near the spray plume. After which, the flame propagated into the syngas in the piston bowl and then proceeded toward the syngas in the squish zone. With the baseline injection system and piston shape, a significant amount of unburned syngas was discharged. To solve this problem, effects of the injection parameters and piston shape on combustion characteristics were analyzed by calculation. The change in injection variables toward increasing the spray plume volume or the penetration length were effective to cause fast burning in the vicinity of TDC by widening the spatial distribution of diesel acting as a seed of auto-ignition. As a result, the unburned syngas fraction was reduced. Changing the piston shape with the shallow depth of the piston bowl and 20% squish area ratio had a significant effect on the combustion pattern and lessened the unburned syngas fraction by half.