• Elastomers and Composites
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• v.34 no.2
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• pp.156-176
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• 1999

Rubber chemicals such as accelerators, antidegradants, vulcanizing agents, processing agents and retarders are very important to the production and protection of tires and rubber goods. The use of accelerators and antidegradants are evaluated in various tire components. This paper will focus on how to vulcanize tires economically and maintain the physical properties of each tire component without severe degradation due to oxygen, heat and ozone. Also, new non-nitrosoamine accelerators and non-staining antiozonants will be discussed. Lastly, the future requirements of antidegradants and accelerators in the tire industry will be reviewed. Tires have been vulcanized with Sulfenamides as primary accelerators and either Guamdine's or Thiurams as secondary accelerators to achieve proper properties at service conditions. However, interior components such as the carcass can be vulcanized with Thiazoles as a primary accelerator to cure faster than the external components. Using the combination of Sulfenamide with secondary accelerators in a tire tread compound and the combination of a Thiazole and Guanidine in a carcass compound will be presented with performance data. Uniroyal Chemical and another Rubber Chemical Manufacturer have developed, "Tetrabenzyl Thiuram Disulfide," (TBzTD) as a non-Nitrosoamine accelerator, which could replace Nitrosoamine generating Thiurams. This new accelerator has been evaluated in a tread compound as a secondary accelerator. Also, Flexsys has developed N-t-butyl-2-benzothiazole Sulfenamide (TBSI) as a non-Nitrosoamine accelerator which could replace 2-(Morpholinothio) -benzothiazole (MBS), a scorch delayed Sulfendamide accelerator. TBSI has been evaluated in a Natural Rubber (NR) belt skim compound vs. MBS. An optimum low rolling resistant cure system has been developed in a NR tread with Dithiomorpholine (DTDM). Also, future requirements for developing accelerators will be discussed such as the replacement of DTDM and other stable crosslink systems. Antidegradants are divided into two different types for use in tire compounds. Internal tire compounds such as apex, carcass, liner, wire breaker, cushion, base tread and bead compounds are protected by antioxidants against degradation from oxygen and heat due to mechanical shear. The external components such as sidewall, chafer and cap tread com-pounds are protected from ozone by antiozonants and waxes. Various kinds of staining and non-staining antioxidants have been evaluated in a tire carcass compound. Also, various para-phenylene diamine antiozonants have been evaluated in a tire sidewall compound to achieve the improved lifetime of the tire. New non-staining antiozonants such as 2, 4, 6-tris-(N-1, 4-dimethylpentyl-p-phenylene diamine) 1, 3, 5 Trizine (D-37) and un-saturated Acetal (AFS) will be discussed in the tire sidewall to achieve better appearance. The future requirements of antidegradants will be presented to improve tire performance such as durability, better appearance and longer lasting tires.

• Journal of Service Research and Studies
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• v.10 no.2
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• pp.31-42
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• 2020

This study is a study on the performance of design services among export voucher projects. In particular, we have identified the actual state of use of design services from the perspective of participating companies and the corresponding problems. The purpose of the study is to provide basic data for the preparation of successful support plans in the field of design services. This study designed a quantitative survey to measure accurate performance of design services using archive records, and the survey was sent three times in total to 135 participating companies. A significant achievement of design services the study found is that the role of design were important in the export of the nation's main industries such as medical/biological/healthcare and electrical/electronic products. In addition, we could see that all participating companies were using design services regardless of the difference in sales. In particular, 96% of participating companies answered that the design service effect was the most effective service. As a result, it proved the importance of design services in export voucher projects, and suggested the importance of introducing a management system as a direction for the development of design services in future export voucher projects. He majored in advertising design at Hongik University's Graduate School of Industrial Art and at the Korea Institute of Design Promotion. It carries out the government's design policy such as design research, design education, and corporate design support. He is currently working as an Invited Designer by Korea Design Exhibition.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.6
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• pp.481-491
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• 2005

Purpose: The aim of the present study is to evaluate the effect of autogenous bone and allograft material coverd with a bioresorbable membrane on bone regeneration after a simultaneous installation of implant. Materials and methods: Twelve healthy rabbits, weighing about $3{\sim}4$ kg, were used in this experiment. Following impalnt(with 3.25 mm diameter and 8 mm length) site preparation by surgical protocol of $Oraltronics^{(R)}$, artificial bony defect, 5mm sized in height and depth, was created on femoral condyle using trephine drill(with 5 mm diameter and 5 mm length). Then implant was inserted. In the experimental group A, the bony defect was filled with autogenous particulated bone and coverd with $Lyoplant^{(R)}$ resorbable membrane. In the experimental group B, the bony defect was filled with allograft material(Orthoblast $II^{(R)}$) containing demineralized bone matrix and covered with $Lyoplant^{(R)}$. In the control group, without any graft materials, the bony defect was covered with $Lyoplant^{(R)}$. The experimental group A and B were divided into each 9 cases and control group into 3 cases. The experimental animals were sacrificed at 3, 6 and 8 weeks after surgery and block specimens were obtained. With histologic and histomorphometric analysis, we observed the histologic changes of the cells and bone formation after H-E staining and then, measured BIC and bone density with KAPPA Image $Base^{(R)}$ system. Results: As a result of this experiment, bone formation and active remodeling process were examined in all experimental groups and the control. But, the ability of bone formation of the experimental group A was somewhat better than any other groups. Especially bone to-implant contact fraction ranged from 12.7% to 43.45% in the autogenous bone group and from 9.02% to 29.83% in DBM group, at 3 and 8 weeks. But, bone density ranged from 15.67% to 23.17% in the autogenous bone group and from 25.95% to 46.06% in DBM group at 3 and 6 weeks, respectively. Although the bone density of DBM group was better than that of autogenous bone group at 3 and 6weeks, the latter was better than the former at 8 weeks, 54.3% and 45.1%, respectively. Therefore these results showed that DBM enhanced the density of newly formed bone at least initially.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.93-100
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• 2016

The purpose of this study was to compare the changes of retentive force in different stud attachment systems for implant retained overdenture. Two commercially available attachments with different retentive forces were investigated: Kerator (pink, blue, red) and O-ring (orange, red). Two implant fixtures were vertically embedded in base mountings. Five pairs of each attachment were evaluated. A universal testing machine was used to evaluate the retentive force of two attachments during wear simulation. Surface characteristics of each attachment system were evaluated with scanning electron microscopy. Five pairs of each attachment were evaluated. Kerator pink showed the highest initial retention. After 2,500 cycles of wear-simulation, Kerator pink noted the largest decrease in retention. According to results of surface analysis, Worn surfaces were obtained in matrices and patrices. Heavy wears were observed in matrices. After 2 year-wear simulation, most attachments exhibited retention loss. Attachments using different kind of material exhibited dissimilar surface alterations.

• Journal of IKEEE
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• v.19 no.2
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• pp.186-192
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• 2015

This paper proposes an automatic generation technology of test case based on API in source code for software's quality improvement. The proposed technology is comprised of four processes which are analyzing source code by using the Doxygen open source tool, defining API specification by using analyzed results, creating test design, generating a test case by adapting Pairwise test technology. Analyzing source code by using the Doxygen open source tool is the phase in which API information in source code such as the API name, input parameter and return parameter are extracted. Defined API specification by using analyzed results is the phase where API informations, which is needed to generate test case, are defined as a form of database by SQLite database on the basis of extracted API information. Creating test design is the phase in which the scenario is designed in order to be composed as database by defining threshold of input and return parameters and setting limitations based on the defined API. Generating a test case by adapting Pairwise test technique is the phase where real test cases are created and changed into database by adapting Pairwise technique on the base of test design information. To evaluate the efficiency of proposed technology, the research was conducted by begin compared to specification based test case creation. The result shows wider test coverage which means the more cases were created in the similar duration of time. The reduction of manpower and time for developing products is expected by changing the process of quality improving in software developing from man-powered handwork system into automatic test case generation based on API of source code.

• Korean journal of communication and information
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• v.71
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• pp.33-51
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• 2015

In South Korea, the community building projects and so-called 'community businesses' are recently regarded as one of the popular issues for the local people and social activists. The project seems to be a miracle resolution for various social matters such as the deteriorating welfare, health care, security system and the worsening income problem, etc. But these promising social discourses and practices which encourage to build communities are not only constructing 'good governance' for the sound cooperation between the state and civil society, but also allowing government technologies to manage and regulate civil society and citizens. This irony of building community is not yet thoroughly considered. The aim of this article is to ask 'Is building community good for all of people?'; 'How does community guarantee the freedom of people who participate in?'. The reflection for community in South Korean Society has related to The May 18-community in Gwangju. The May 18-community is a keystone for understanding the ethos and pathos of community. This study tries to unravel the relation between the May Uprising and the idea of community throughout affects and hearts of participants. The lived experience and testimony of the people of Gwangju in May, 1980, reveals that community should not be in an order and an notion of security. Examining hearts of members of 'whatever community' in the May Uprising is essential to imagine a new form of community which incorporates liberation and freedom as its base.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.3
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• pp.23-35
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• 2012

The optimum location of the prehistoric sites of Ulsan Metropolitan City are investigated by both quantile and natural breaks methods through GIS, and the settlement pattern is studied based on the possibility of presence of the prehistoric sites which are also analyzed with these methods. Such factors including elevation, slope, distance from the nearest water, aspect, geological features, soil drainage classes, subsoil and land use recommended are employed in the analysis. The optimum geographical environment is the place where it includes the water-base in the area that is the southern aspect of the gentle slope land of lowland. The geology is the Quaternary alluvium. The drainage class is fine and the deep soil saturn is the fine loamy soil and the recommendation of land use is the area that is the field. As a result of the forecast of distribution, the prehistoric sites showed the higher possibility of presence in the downstream region where the Taehwa river and Dongcheon river join because the region come close to the watercourse and the drinking water use is easy. And the aspect and elevation is the low area. The alluvium accumulated from the upper stream of the Taehwa river and Dongheon river was made roomily, the area where is suitable for the farming life. Therefore, this region is judged that the possibility of presence of the prehistoric sites is high.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.110-126
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• 1995

Korean economy has been developed successfully in the course of implementing the five year economic development plans since 1962. The gap of incomes and quality of life between rural and urban area has been widened and it made rural farm laborers drain to urban areas. Therefore the prevailing situation of labor shortage and wage hike in rural area has made farm management deteriorate in recent years. Under the internal and international unfavorable economic conditions, marginal farm land of 66.5 thousand ha has been idled as of end of 1993. The total area outside agricultural development zone with bad farming conditions including irrigation and drainage, and land consolidation for mechanization were estimated at 360.4thousand ha equivalent to 17.5% of the total farm land area in Korea. Considering the topographical conditions of marginal lands, the effective use of marginal lands should be studied from the view point of public interest rather than from the view point of individual economic conditions. Considering the present agricultural economic settings, such as price decrease, unfavourable benefits of farm products, labour shrotage, free trade of farm products and poor physical condition of marginal lands, the institutional and realistical measures for the effective utilization of idle and marginal land should be studied as soon as possible. Detail land use pattern should be surveyed in the areas outside agricultural development zone and have to be classified as orchard farms, grass land, fish culture farms, lawn and ornamental tree farm, sight seeing and leisure farms for urban peoples, special crops production farms and common farms to be developed for farm mechanization. According to the surveyed results, the expected utilization patterns of the idle and marginal lands could be considerd as village common use, farm land base development, leisure farm development, mutual complementary utilization between urban and rural areas, G't purchase and management, credit supply and new extension services, improvement of cropping patterns and sight seeing and leisure farm patterns. For the successful and reasonable management of the marginal lands, the actions such as institutional improvement, prohibition of idle marginal land, enforcement of activities of farm management committee members and land banking system of RDC including development and utilization systems should be included.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.191-197
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• 2010

The objective of this research was to determine the influence of the physical and chemical properties of root substrates used during the production of 'Maehyang' strawberry propaguleson the growth of the mother plants and the rate of daughter plant formation. Plants were cultured in plastic bags containing six different formulations of root substrates composed of: a) 50% coir dust and 50% perlite (5:5 by volume, A), b) 60% coir dust and 40% perlite (6:4, B), c) 70% coir dust and 30% perlite (7:3, C), d) 70% coir dust and 30% coconut chip (7:3 D), e) 60% coir dust and 40% coconut chip (60:40, E), or f) 50% sphagnum peat and 50% vermiculite (50:50, F). All media formulations contained a moderate level of base fertilizers. Physical and chemical properties of each formulation were determined before plant establishment and after 120 days of stock plant culture and runner production. Total porosity (TP) and container capacity (CC) of all substrate formulations were higher than 85% and 55%, respectively, allowing a suitable range of air and water holding characteristics. Formulation F provided the highest TP and CC values among the all substrate modifications evaluated. Substrate formulations A, B, C and F had higher electrical conductivity (EC) and $NO_3{^-}$-N concentrations than formulations D and E, when determined before and after plant culture. Formulations A, B, C, and F, having higher EC readings, also performed better as root substrates thanthe formulations D and E in increasing fresh and dry weights of the runners as well as the production of daughter plants per plant. The 'Maehyang' strawberry plants grown in the formulation F had the highest tissue N content, followed by those grown in substrate B, A, C, or D for 120 days after transplanting. Formulation F also facilitated accumulation of higher tissue phosphorus (P) and copper (Cu) contents compared to other treatments. Results of this experiment suggest that the chemical properties, rather than physical properties, of root substrates had a major influence on the growth of mother plants and the occurrence of healthy daughter plants during the bag-culture phase of propagation.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.266-272
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• 2003

This study was conducted to evaluate effects of 2 constructed wetlands with different vegetation states (plumpton park wetland and Woodcroft park wetland) for reducing non-point source pollution from small watershed consisted of residential and agricultural area in suburban district of Sydney, Australia. The total nitrogen and phosphate removal efficiency of Plumpton park constructed wetland, composed of stable and dense vegetation, were 38.3% and 26.2% and Woodcroft park constructed wetland having still poor vegetation due to the short time to settle down transplanted plants after construction, showed relatively low removal efficiency of 20.2% and 14.0%. The removal efficiency of inorganic nutrients such as $NH_4-N$, $NO_3-N$, $PO_4^{-3}$ were higher than total nitrogen and phosphate because plants and microorganisms in rhizosphere of constructed wetlands took up inorganic nutrients shortly. According to the type of wetland inflow, the nutrients removal efficiency of storm water flow was lower than base flow.