• 자원리싸이클링
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• 제11권2호
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• pp.36-44
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• 2002

폐기처분되는 gamet 미분말의 재활용 측면에서 이를 적벽돌의 원료로 활용하는 방안에 관한 연구를 수행하였다. 적벽돌의 물리적 강도에 있어서 점토가 높은 $SiO_2$, $Al_2$$O_3$및 $Fe_2$$O_3$함량과 점성을 가지는 것은 매우 중요한 성질이다. 그러나 폐garnet 미분말의 경우 이들의 함량은 높지만 점성이 매우 작으므로, 점토를 대체할 수 없을 것으로 판단하여 모래의 대체제로 적용하고자 하였다. 점토의 화학성분 중 강도를 나타내는 함량이 폐garnet 미분말에서도 상당히 높은 것으로 파악되었으며, 이는 적벽돌의 강도에 긍정적인 영향을 주는 것으로 파악되었다. 적벽돌 제조시의 원료 배합은 {점토-모래}, {모래-폐gamet 미분말}, 그리고 {점토-모래-폐gamet 미분말} 조합을 무게 비율로 각각 조절하였으며, 적벽돌 공시체의 물리적 특성 실험은 압축강도.흡수율.수축율.비중에 대하여 실시하였다. 그 결과 최적의 원료 배합 조건은 무게를 기준으로 할 때 {점토50%+모래 30%+폐 gamet 미분말 20%}인 것으로 파악되었다. 본 연구의 결과 폐gamet 미분말을 재활용하여 제작한 적벽돌의 상업적 생산이 가능하며, 유효자원의 재이용 측면에서도 경제성을 가질 것으로 판단되었다.

• 유통과학연구
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• 제13권7호
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• pp.41-51
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• 2015

Purpose - This study analyzes loading efficiency by loading pattern for package standardization and reduction of logistics costs, along with the creation of revenue for the revenue review panel (RRP) of Membership Wholesale Clubs (MWC). The study aims to identify standard dimensions that can help improve the compatibility of the pallets related to display patterns preferred by the MWC and thereby explore ways to enhance logistics efficiency between manufacturers and retailers through standardization. Research design, data, and methodology - The study investigates and analyzes the current status based on actual case examples, i.e., manufacturer A and Korea's MWC (A company, B company, and C company), and thus devises improvement measures. To achieve this, the case of manufacturer A delivering to MWC was examined, and the actual pallet display patterns for each MWC were investigated by visiting each distribution site. In this study, TOPS (Total Optimization Packaging Software, USA) was used as the tool for pallet loading efficiency simulations the maximum allowable dimension was set to 0.0mm to prevent the pallet from falling outside the parameters, and the loading efficiency was analyzed with the pallet area. In other words, the study focused on dimensions (length x width x height) according to the research purpose and thereby deduced results. Results - The analysis of pallet loading patterns showed that the most preferred loading patterns for loading efficiency according to product specification, such as pinwheel, brick, and block patterns, were used in the case of the general distribution products, but the products were configured with block patterns in most cases when delivered to MWCs. The loading efficiency by loading pattern was analyzed with respect to 104 nationally listed standard dimensions. Meanwhile, No.51 (330 × 220mm) of KS T 1002 (1,100 × 1,100mm) was found to be the dimension that could bring about an improved loading efficiency, over 90.0% simultaneously in both the T-11 and T-12 pallet systems in a loading pattern configuration with the block pattern only, and the loading efficiency simulation results also confirmed this as the standard dimension that can be commonly applied to both the T-11 pallet (90.0%) and the T-12 pallet (90.7%) systems. Conclusions - The loading efficiency simulation results by loading pattern were analyzed: For the T-11 pallet system, 17 standard dimension sizes displayed the loading efficiency of 90.0% or more as block patterns, and the loading capacity was an average of 99.0%. For the T-12 pallet system, 35 standard dimension sizes displayed the loading efficiency of more than 90% as block patterns (the average loading efficiency of 98.6%). Accordingly, this study proposes that the standard dimensions of 17 sizes with the average loading efficiency of 99.0% should be applied in the use of the T-11 pallet system, and those of 35 sizes with the average loading efficiency of 98.6% should be reviewed and applied in the use of the T-12 pallet system.

• 한국산업보건학회지
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• 제9권1호
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• Asia pacific journal of information systems
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• 제17권2호
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• pp.29-47
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• 2007

Owing to the rapid growth of using the Internet, not only click-and-mortar companies but also brick-and-mortar ones have been expanding their distribution channels into online, Moreover, since online channels are more attractive than offline ones in control and maintenance, switching customers into online ones is emerged as one of very important managerial issues in a view of reduction of cost as well as expansion of services. However, the switched customers should be faced by uncertainties which could not have been experienced in offline. Specifically, in online channels, buyers and sellers are separated temporally and spacially and there are always so many kinds of threat for security as well as not enough systems and conventions for them yet. Therefore, trust has been considered as one of the most critical mechanisms for resolution of such uncertainties in online transactions. However, it is not easy to build and maintain the relationships in online since most of them are virtual and indirect generally. Therefore, in order to switch offline customers into online ones, it is very important to make strategies based on identification of the relationship between online transaction and offline trust which has been built in offline business. Generally offline trust, which has been built independent of online, could not include trust for online-dependent activities such as payment security during or after transactions, while most of online trust include it. Therefore, a customer with high offline trust does not always perceive high security and assure safe transactions. Accordingly, while online trust, where technical capabilities for online security is one of main bases, includes control trust implicitly or explicitly, offline trust does not. However. in spite of such clear discrimination and independence between offline trust and perceived security, there can be the significant dependency between these two beliefs. The customers with high offline trust believe that the company would do some activities for online security for customers' safe transactions since it has been believed of doing well for customers' trust. Theoretically, users' perception of security is interpreted as a kind of control trus, which is trust for company's technical control capacities in order to resolve technical uncertainties in online. Therefore, the relationship between two beliefs can be considered as transference from offline trust to another type trust. that is, control trust. The objective of this study is to analyze the effect of offline trust on online transaction uses mediated by perceived security. For this purpose, we suggest a research model based on technology acceptance model (TAM). Reuse intention is adopted as a dependent variable and TAM is modified by adding perceived risk (PR) as well as two beliefs of using Internet banking, perceived usefulness (PU) and perceived ease of use (PEOU). Moreover, perceive security (PS) is adopted as an external variable for PR and PU, while offline trust (OT) is an antecedent of PS. For an empirical test, sampling from 108 visitors to the banks in Daegu, Korea, we analyze our model by partial least square (PLS) approach. In result, our model is shown to explain 51.4% of the variance in reuse intention and all hypothesis are supported statistically. A theoretical implication of this study is to identify a role of PS between offline trust and reuse intention of using online transaction services. According to our result, PS can be considered as a mediation variable for bridging between two different concepts: trust that explains social aspects of customers and companies, and TAM that explains customers' reuse intention.

• World Technopolis Review
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• 제8권2호
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• pp.74-81
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• 2019

Cities will soon host two third of the population worldwide, and already today 80% of the world energy is used in the 20 largest cities. Urban areas create 80% of the greenhouse gas emission, so we should take care that urban areas are smart and sustainable as implementations have especially here the greatest impact. Smart Cities (SC) or Smart Sustainable Cities (SSC) are the actual concepts that describe methodologies how cities can handle the high density of citizens, efficiency of energy use, better quality of life indicators, high attractiveness for foreign investments, high attractiveness for people from abroad and many other critical improvements in a shifting environment. But if we talk about Entrepreneurship Ecosystem and Innovation, we do not see a lot of literature covering this topic within those SC/SSC concepts. It seems that 'Smart' implies that all is embedded, or isn't it properly covered as brick stone of SC/SSC concepts, as they are handled in another 'responsibility silo', meaning that the policy implementation of a Science and Technology Park (STP) is handled in another governing body than SC/SSC developments. If this is true, we will obviously miss a lot of synergy effects and economies of scale effects. Effects that we could have in case we stop the siloed approaches of STPs by following a more holistic concept of a Smart Sustainable City, covering also a continuous flow of innovation into the city, without necessarily always depend on large corporate SSC solutions. We try to argue that every SSC should integrate SP/STP concepts or better their features and services into their methodology. The very limited interconnectivity between these concepts within the governance models limits opportunities and performance in both systems. Redesigning the architecture of the governance models and accepting that we have to design a system-of-systems would support the possible technology flow for smart city technologies, it could support testbed functionalities and the public-private partnership approach with embedded business models. The challenge is of course in complex governance and integration, as we often face siloed approaches. But real SSC are smart as they are connecting all those unconnected siloes of stakeholders and technologies that are not yet interoperable. We should not necessarily follow anymore old greenfield approaches neither in SSCs nor in SP and STP concepts from the '80s that don't fit anymore, being replaced by holistic sustainability concepts that we have to implement in any new or revised SSC concepts. There are new demands for each SP/STP being in or close to an SC/SCC as they have a continuous demand for feeding the technology base and the application layer and should also act as testbeds. In our understanding, a big part of STP inputs and outputs are still needed, but in a revised and extended format. We know that most of the SC/STP studies claim the impact is still far from understood and often debated, therefore we must transform the concepts where SC/STPs are not own 'cities', but where they act as technology source and testbed for industry and new SSC business models, being part of the SC/STP concept and governance from the beginning.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.291-316
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• 1993

Restorative procedures can lead to tooth fracture due to the relatively small amount of the remaining tooth structure. It is essential to prevent fractures by having a clear concept of the designs for cavity preparations. Among the several parameters in cavity designs, profound understanding of isthmus width factor would facilitate selection of the appropriate cavity preparation for a specific clinical situation. In this study, MO amalgam cavity were prepared on maxillary first premolar and filled with amalgam. Three dimensional, model with 1365 8-node brick elements was made by serial photographic method. In this model, isthmus was varied in width at 1/4, 1/3, 1/2 and 2/3 of intercuspal width and material properties were given for three element groups, i.e., enamel, dentin and amalgam. A load of 500 N was applied vertically on amalgam and enamel. In case of enamel loading, 2 model (with and without amalgam) was compared to consider the possibility of play at the interface between tooth material and amalgam. These models were analyzed with three dimensional finite element method. The results were as follows: 1. The stress was concentrated on the facio-pulpal line angle and distal marginal ridge of the cavity. 2. With the increase of the isthmus width, the stress spread around the facio-pulpal line angle and the area of stress concentration moved toward the proximal box. 3. In case of narrow isthmus width, the initiation point of crack would be in the area of isthmus corner of the cavity, and with the increase of the isthmus width, it would move toward the proximal box and at the same time the possibility of crack increase at the distal marginal ridge. 4. The direction of crack progressed outward and downward from the facio-pulpal line angle, and with the increase of the isthmus width, it approximated vertical direction. At the marginal ridge, it occurred in vertical direction. 5. It would be favorable to make the isthmus width narrower than a third of the intercuspal width, and to cover the cusp if isthmus width were wider than half of the intercuspal width. 6. It is necessary to apply the possibility of play to the finite element analysis.

• 분석과학
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• 제30권5호
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• pp.252-261
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• 2017

천연방사성핵종을 함유한 물질들은 인간 활동에 의해 인위적인 조작과정을 거치면서 농축되는 경우 방사선 노출에 따른 위해를 증가시킬 수 있다. 본 연구는 다양한 전처리 방법 및 분석 방법 간 비교를 통해 분석정확도를 평가하고 실내 건축자재 중 $^{232}Th$, $^{235}U$, $^{238}U$의 천연방사성핵종을 분석하기 위한 최적의 분석 방법을 확립하고자 하였다. ICP-MS를 이용한 실내 건축자재 중 천연방사성핵종 분석방법을 확립하기 위하여, 인증표준물질 5종을 왕수, 불산, 과염소산의 습식산화법과 용융법의 전처리법에 따른 U, Th의 분석 정확도 및 정밀도를 평가하였고, 최적의 전처리법으로써 용융법과 $Fe(OH)_3$ 공침법을 선정하였다. 확립된 분석방법을 석고보드, 벽돌, 시멘트, 페인트, 타일과 벽지 총 51 종의 실내 건축자재 시료에 적용하여 천연방사성핵종의 농도를 정량 분석하였다. 또한 동일한 시료에 대해 감마분광분석법 중 간접측정법을 사용하여 $^{238}U$, $^{232}Th$의 농도를 정량하고 ICP-MS 분석 결과와 비교하였다.

• 콘크리트학회논문집
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• 제23권3호
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• pp.331-338
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• 2011

이 연구는 미생물 혹은 생물의 다양한 기능을 이용한 환경의 수복(bioremediation)을 활용한 자연 친화형 수질 정화 시멘트 벽돌로서의 가능성을 검토하고자 하였다. 현재 유용 미생물을 건축 소재에 활용하여 수질을 개선하는 연구들이 제안되어 왔다. 이 연구에서는 이러한 미생물의 수질 정화 능력을 이용하는 것으로서 선행 연구의 낫토균 이외에 된장균, 대구 S환경사업소에서 미생물을 탐색하여 16S rDNA 염기서열 분석법에 의해 동정된 유용 미생물 자원들을 이용하였으며, 이렇게 확보된 수질 정화 능력을 가진 유용 미생물 자원들에 대한 시멘트 벽돌에서의 수질 정화 특성을 검토하였다. 또한 시멘트 벽돌에 미생물을 흡착시키기 위하여 제올라이트를 사용 하였으며, SEM 분석을 통하여 제올라이트에 미생물이 흡착되어 있는 것을 확인 할 수 있었다. 실험 결과 유용 미생물을 이용 하였을 때 우수한 오염물질 제거율이 나타났기 때문에 자연 친화형 건설재료의 유용 미생물 활용이 가능하다고 판단되며, 이 연구에서 소개한 미생물 이외에도 다양한 미생물 자원들을 확보하여 건축 소재에 활용 가능한 수질 개선용 유용 미생물 자원들을 확보할 수 있을 것으로 기대된다.

• 대한지리학회지
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• 제51권3호
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• pp.441-454
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• 2016

이 연구는 지붕 형태, 지붕 재료, 외벽 재료에 초점을 두고 울릉도 산지 촌락 가옥의 유형과 특성을 고찰하는 연구이다. 그리고 울릉도 산지의 촌락 가옥 유형을 제주도와 경남의 촌락 가옥 유형과 비교하면서 그 특성도 논의한다. 울릉도 산지 촌락 가옥의 지붕 형태를 보면, 팔작지붕(42.1%)이 가장 많이 나타나고, 그 다음으로는 맞배지붕(25.8%), 우진각지붕(11.8%), 단순평지붕(10.7%) 등이 많이 나타난다. 지붕 재료를 보면, 컬러강판(69.1%), 아스팔트싱글(11.8%), 시멘트(10.7%) 등이 많이 나타난다. 컬러강판을 지붕 재료로 사용한 가옥이 압도적으로 많고, 기와나 슬레이트를 지붕 재료로 사용한 가옥은 한 채도 없다. 그리고 외벽 재료에서는 시멘트(27.5%), 사이딩(21.3%), 함석(16.8%), 목재(6.7%) 등이 많이 나타난다. 지붕 형태와 지붕 재료의 결합 관계로 본 가옥 유형에서는 팔작지붕-컬러강판 가옥 유형(73채; 41.0%)이 가장 많이 나타나고, 지붕 형태를 중심으로 해서 지붕 재료와 외벽 재료의 결합 관계로 본 가옥 유형에서는 팔작지붕-컬러강판-시멘트 가옥 유형(32채; 18.0%)이 가장 많이 나타난다. 울릉도 산지 촌락 가옥의 지붕/외벽 재료로 함석을 사용하는 빈도가 높은 것, 기와나 슬레이트를 지붕 재료로 사용하지 않는 것, 적벽돌이나 석재를 외벽 재료로 사용하는 빈도가 낮은 것 등은 건축 자재의 운송비용과 관련이 있을 것이다.

• Interdisciplinary Bio Central
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• 제4권3호
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• pp.10.1-10.12
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• 2012

Introduction: We investigated frameshift suppressor tRNAs previously reported to use five-base anticodon-codon interactions in order to provide a collection of frameshift suppressor tRNAs to the synthetic biology community and to develop modular frameshift suppressor logic devices for use in synthetic biology applications. Results and Discussion: We adapted eleven previously described frameshift suppressor tRNAs to the BioBrick cloning format, and built three genetic logic circuits to detect frameshift suppression. The three circuits employed three different mechanisms: direct frameshift suppression of reporter gene mutations, frameshift suppression leading to positive feedback via quorum sensing, and enzymatic amplification of frameshift suppression signals. In the course of testing frameshift suppressor logic, we uncovered unexpected behavior in the frameshift suppressor tRNAs. The results led us to posit a four-base binding hypothesis for the frameshift suppressor tRNA interactions with mRNA as an alternative to the published five-base binding model. Conclusion and Prospects: The published five-base anticodon/codon rule explained only 17 of the 58 frameshift suppression experiments we conducted. Our deduced four-base binding rule successfully explained 56 out of our 58 frameshift suppression results. In the process of applying biological knowledge about frameshift suppressor tRNAs to the engineering application of frameshift suppressor logic, we discovered new biological knowledge. This knowledge leads to a redesign of the original engineering application and encourages new ones. Our study reinforces the concept that synthetic biology is often a winding path from science to engineering and back again; scientific investigations spark engineering applications, the implementation of which suggests new scientific investigations.