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        검색결과 46

        1.
        2023.05 구독 인증기관·개인회원 무료
        Metakaolin-based geopolymers have shown promise as suitable candidates for 14C immobilization and final disposal. It has been shown that the physicochemical properties of metakaolin wasteforms meet, and often far exceeding, the strict compression strength and leaching acceptance criteria of the South Korea radioactive waste disposal site. However, it is not possible to analyze and characterize the internal structure of the geopolymer wasteform by conventional characterization techniques such as microscopy without destruction of the wasteform; an impractical solution for inspecting wasteforms destined for final disposal. Internal inspection is important for ensuring wastes are homogenously mixed throughout the wasteform and that the wasteform itself does not pose any significant defects that may have formed either during formulation and curing or as a result of testing prior to final disposal. X-ray Computed Tomography (XCT) enables Non-Destructive Evaluation (NDE) of objects, such as final wasteforms, allowing for both their internal and external, characterization without destruction. However, for accurate quantification of an objects dimensions the spatial resolution (length and volume measures) must be know to a high degree of precision and accuracy. This often requires extensive knowledge of the equipment being used, its precise set-up, maintenance and calibration, as well as expert operation to yield the best results. A spatial resolution target consists of manufactured defects of uniformed dimensions and geometries which can be measured to a high degree of accuracy. Implementing the use of a spatial resolution target, the dimensions of which are known and certified independently, would allow for rapid dimensional calibration of XCT systems for the purpose of object metrology. However, for a spatial resolution target to be practical it should be made of the same material as the intended specimen, or at least exhibit comparable X-ray attenuation. In this study, attempts have been made to manufacture spatial resolution targets using geopolymer, silica glass, and alumina rods, as well as 3D printed materials with varying degrees of success. The metakaolin was activated by an alkaline activator KOH to from a geopolymer paste that was moulded into a cylinder (Diameter approx. 25 mm). The solidified geopolymer cylinder as well as both the silica glass rod and alumina rod (Diameter approx. 25 mm) we cut to approximately 4 mm ± 0.5 mm height with additional end caps cut measuring 17.5 mm ± 2.5 mm height. All parts were then polished to a high finish and visually inspected for their suitability as spatial resolution targets.
        3.
        2022.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The nuclear legacy that remains in the United Kingdom (UK) is complex and diverse. Consisting of legacy ponds and silos, redundant reprocessing plants, research facilities, and non-standard or one-off reactor designs, the clean-up of this legacy is under the stewardship of the Nuclear Decommissioning Authority (NDA). Through a mix of prompt and delayed decommissioning strategies, the NDA has made great strides in dealing with the UK’s nuclear legacy. Fuel debris and sludge removal from the legacy ponds and silos situated at Sellafield, as part of a prompt decommissioning strategy for the site, has enabled intolerable risks to be brought under control. Reactor defueling and waste retrievals across the Magnox fleet is enabling their transition to a period of care and maintenance; accelerated through the adopted ‘Lead and Learn’ approach. Bespoke decommissioning methods implemented by the NDA have also enabled the relevant site licence companies to tackle non-standard reactor designs and one-off wastes. Such approaches have potential to influence and shape nuclear decommissioning decision making activities globally, including in Korea.
        8,100원
        6.
        2021.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The challenges facing companies and institutions surrounding civil nuclear decommissioning are diverse and many, none more so than those faced in the United Kingdom. The UK’s Generation I nuclear power plants and early research facilities have left a ‘Nuclear Legacy’ which is in urgent need of management and clean-up. Sellafield is quite possibly the most illfamed nuclear site in the UK. This complex and challenging site houses much of what is left from the early days of nuclear research in the UK, including early nuclear reactors (Windscale Piles, Calder Hall, and the Windscale Advanced Gas Cooled Reactor) and the UK’s early nuclear weapons programme. Such a legacy now requires careful management and planning to safely deal with it. This task falls on the shoulders of the Nuclear Decommissioning Authority (NDA). Through a mix of prompt and delayed decommissioning strategies, key developments in R&D, and the implementation of site licenced companies to enact decommissioning activities, the NDA aims to safety, and in a timely manner, deal with the UK’s nuclear legacy. Such approaches have the potential to influence and shape other such approaches to nuclear decommissioning activities globally, including in Korea.
        8,000원
        7.
        2021.03 구독 인증기관 무료, 개인회원 유료
        Being an island has often proved a health benefit in dealing with the COVID-19 pandemic. Indeed, after a year of the pandemic, virtually the only COVID-free countries are island states and territories. While both Australia and South Korea have fared well by global standards, their island provinces, Jeju and Tasmania done even better. The small island states of the South Pacific region leveraged their insularity by swiftly closing borders, tough quarantine, social distancing and public health measures when a pandemic was declared. Their marine moat contributed significantly to health security for these islands but at great cost to their fragile economies especially those with some dependence on tourism. Vaccines promise the opportunity to reopen borders to international commerce and traffic. However, the transition out of the pandemic will less swift and less secure than the initial dramatic first response. The apparent inevitability of COVID becoming an endemic disease will require ongoing public health measures as well as political decisions at the level of individual countries as when decide their pandemic measures can be relaxed. Travel bubbles are touted as a likely transitional stage for the global recovery but these have proved more aspirational than practical thus far. Post-COVID financial revitalisation will even more challenging for small island states. It is here that both Jeju and Tasmania can assist their national government in meeting the needs of the Pacific’s small island states. They have relevant island-adapted human and physical technologies that, if recognised and mobilised, could make appropriate niche recovery aid more effective.
        3,000원
        8.
        2020.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Thermal decomposition of the uranyl phosphate mineral phase meta-ankoleite (KUO2PO4·3H2O) has been considered in relation to high temperature thermal sintering for the immobilisation of a uranyl phosphate containing waste. Meta-ankoleite thermal decomposition was studied across the temperature range 25 – 1200℃ under an inert N2 atmosphere at 1 atm. It is shown that the meta-ankoleite mineral phase undergoes a double de-hydration event at 56.90 and 125.85℃. Subsequently, synthetically produced pure meta-ankoleite remains stable until at least 1150℃ exhibiting no apparent phase changes. In contrast, when present in a mixed waste the meta-ankoleite phase is not identifiable after thermal treatment indicating incorporation within the bulk waste either as an amorphous phase and/or as uranium oxide. Visual inspection of the waste post thermal treatment showed evidence of self-sintering owing to the presence of glass former materials, namely, silica (SiO2) and antimony(V) oxide (Sb2O5). Therefore, incorporation of the uranium phase into the waste as part of waste sentencing and immobilisation via high temperature sintering for the purpose of long-term disposal is deemed feasible.
        4,000원
        12.
        2018.07 구독 인증기관·개인회원 무료
        Hospitality and tourism industries have recognized that engaging with customers via social media is now a critical element of their marketing strategy. Given the high variability of success with which firms have been attracting customer interest online, businesses are clearly struggling to determine exactly the right methods to use the newest technologies. This study presents a predictive model of attributes for online posts that evoke a high level of customer engagement. The contribution to the literature is a unique set of features that have significant impact on customer engagement, using a big-data set to support findings. In accordance with theories originating from Social Belongingness and Brand Community Marketing, findings indicate that appeals to a sense of community belonging have a significant impact on customer engagement in social media. Specifically, communities have idiomatic vocabularies consisting of “activation words” that are especially effective for engaging customers on social media. This has both theoretical implications in that it constitutes a large-scale, real-world confirmation of belongingness hypotheses, and managerial implications in that it suggests best practices for maintaining an online presence.
        15.
        2017.10 구독 인증기관·개인회원 무료
        New Zealand split from the rest of Gondwana 65-80 my and is home to approximately 6000 species of beetles, manyof which are undescribed and or poorly studied. Like other iconic groups of New Zealand organisms, the beetle faunais composed of ancient relict lineages and endemic radiations, indicative of an island continental island which never hadopen ecological niches as seen in deep islands such as Hawaii or the Galapagos archipelagos. While more recent volcanismand glaciation as well as the arrival of man within the past 1000 yrs has shaped the population structure and distributionof New Zealand beetles, a new comprehensive model for the evolution of beetles is proposed.
        16.
        2016.06 구독 인증기관·개인회원 무료
        고속도로의 품질 보증을 위해 사용되는 시방서에는 크게 두 가지 종류 1) 방법론적 시방서와 2) 공용성 시방서가 있다. 방법론적 시방서는 목표 공용성 달성을 위해 필요한 방법의 기준과 기준의 목표치를 설정 하여 합격/불합격을 결정하는 반면, 공용성 시방서는 어떤 방법을 이용하든 최종 결과물의 품질을 평가하 여 Incentive/Dis-Incentive를 결정하는 방법이다. 방법론적 시방서는 경제적으로 방법의 기준을 맞추기 위해 노력하지만, 공용성 시방서는 시공업체들의 자체 연구를 통한 품질 향상을 기대할 수 있다. 미국의 경우 공용성 시방서는 2012년 오바마 대통령이 최종 사인한 법안인 MAP-21 (Moving Ahead for Progress in the 21st Century Act)에 의해 법적 근거를 마련하였고, 미국 몇몇 주들(뉴저지, 캘리포니 아, 텍사스, 루이지에나 등)에서 이미 사용하고 있다. 공용성 시방서를 실질적으로 고속도로 현장에 적용하기 위해 요구되어지는 것은 누가나 쉽고 빠르게 공용성 평가할 수 있는 툴을 만드는 것이다. 간단한 시험을 통해 재료의 기본 물성치를 측정하고, 측정된 값을 역학적 재료 모델과 구조해석 프로그램의 입력 값으로 사용하여 공용성을 평가함으로써 어떻게 재료 를 개발해야 하는지와 품질 관리를 할수 있을 것인가에 대한 가이드라인도 할 수 있다. 본 연구에서는 아 스팔트 재료의 피로균열과 소성변형의 공용성을 평가하기 위해 NCHRP 9-19와 9-29을 통해 개발된 간 단한 시험 장비인 Asphalt Mixture Performance Tester (AMPT)와 FHWA Hot Mix Asphalt Performance-Related Specification Based on Viscoelastoplastic Continuum Damage Models를 통 해 개발된 모델들과 3D FEM 구조해석 프로그램을 이용하였다. 개발된 모델과 구조해석 프로그램은 미 국, 캐나다, 브라질, 중국, 한국 등의 시험도로를 통해 검증되었다. 공용성 시방서를 현장에 적용하기 위하여 아스팔트 혼합물의 주요 부피 특성들 (Design VMA, Design Air Void, Density)과 공용성과의 관계를 배합 설계 단계에서 파악하였다. 이 관계를 파악하는 것을 공용 성에 근거한 배합 설계라고 하며, 현장에서 역학적 시험 없이 기존의 품질 보증 시방서에서 수행하던 부 피 특성을 측정하는 것으로 공용성을 예측할 수 있다. 골재의 입도가 공용성에 미치는 영향을 분석하기 위하여 Bailey Method를 사용하였다. Bailey Method는 골재의 Packing Principle을 이용하여 골재 입 도에 따른 VMA를 예측함으로써 배합설계의 시행착오를 줄일 수 있다. 12.5mm Superpave 고온 아스팔트 혼합물의 공용성에 근거한 배합 설계 결과, 아스팔트 혼합물의 골재 입도를 간접적으로 표현하는 Design VMA가 부피 특성들 (Volumetrics) 중 피로균열과 소성변형 공용성에 미치는 영향이 가장 큰 것으로 나타났다. Design VMA가 1% 증가할 때, 피로 균열이 73% 감소하고 소성변 형이 32% 증가하였다. 반면, Design Air Void가 1% 증가할 때, 피로균열이 40% 증가하고 소성변형이 22% 감소하였다. 마지막으로 In-Place Air Void (다짐도)가 1% 증가할 때 피로균열이 19% 증가하고 소성변형 또한 10% 증가 하였다. 공용성에 근거한 배합 설계는 Pay Factor와 Incentive/Dis-Incentive 산출에 사용 될 수 있으며 현장에서 아스팔트 혼합물의 부피 특성들을 어떻게 조정해야 하는 가이드라인을 제시 할 수 있다. 마지막으로 공용성에 근거한 배합 설계를 두 개의 아스팔트 층에 적용하여 피로균열과 소성변형의 공 용성이 최적화 될 수 있는 각층의 배합 설계 기준들을 제시하였다. 본 연구에서 소개된 공용성에 근거한 배 합설계 방법은 아스팔트 혼합물의 부피 특성을 공용성에 근거하여 어떻게 조정해야 하는지를 다양한 아스팔 트 포장의 구조에 맞게 제시한다. 추후 아스팔트 덧씌우기 (혹은 복합 포장) 공법과 포장의 두께를 산정할 때 근거자료로 활용할 수 있다.
        17.
        2016.04 구독 인증기관·개인회원 무료
        The pursuit of fungal biocontrol agents is a complex process but there can be no doubt that the process of finding an optimal isolate for a particular target needs to draw on a large-scale program to assess many candidate cultures. The supply of such cultures is facilitated by the existence of so enormous, comprehensive and accessible source of germplasm as exists in the USDA-ARS Collection of Entomopathogenic Fungal Cultures (ARSEF). This collection includes more than 13,000 isolates of more than 710 fungal taxa from 1,300 hosts and substrates from 2,440 locations. The global dependence on very few entomopathogenic fungal species–most notably, species of Beauveria and Metarhizium–is understandable within regulatory and commercial constraints, but might actually represent an undesirable and unhealthy degree of stability in the realm of fungal biocontrol of insect pests. deserves to be reconsidered by broadening the spectrum of highly specific pathogens and the means by which they might be applied. Unfortunately, a recent change in the rules of nomenclature applicable to such pleomorphic fungi as Beauveria, Metarhizium, Isaria, and the numerous other entomopathogens of the ascomycete order Hypocreales have not contributed to stability or certainty in how–and, indeed, which–names of fungal genera are to be applied. Some of the effects of the changes that became effective on 1 January 2012 will be discussed. Many familiar names of entomopathogenic fungi are necessarily changing under these new rules, but the choices of which names much be used and which must be discontinued may not be definitively stabilized until 2023 (at the next International Botanical Congress after the 2017 Congress in Shenzhen, China).
        19.
        2011.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present two large cosmological N-body simulations, called Horizon Run 2 (HR2) and Horizon Run 3 (HR3), made using 60003 = 216 billions and 72103 = 374 billion particles, spanning a volume of (7.200 h-1Gpc)3 and (10.815 h-1Gpc)3, respectively. These simulations improve on our previous Horizon Run 1 (HR1) up to a factor of 4.4 in volume, and range from 2600 to over 8800 times the volume of the Millennium Run. In addition, they achieve a considerably finer mass resolution, down to 1.25 X 1011h-1M⊙, allowing to resolve galaxy-size halos with mean particle separations of 1.2h-1Mpc and 1.5h-1Mpc, respectively. We have measured the power spectrum, correlation function, mass function and basic halo properties with percent level accuracy, and verified that they correctly reproduce the CDM theoretical expectations, in excellent agreement with linear perturbation theory. Our unprecedentedly large-volume N-body simulations can be used for a variety of studies in cosmology and astrophysics, ranging from large-scale structure topology, baryon acoustic oscillations, dark energy and the characterization of the expansion history of the Universe, till galaxy formation science - in connection with the new SDSS-III. To this end, we made a total of 35 all-sky mock surveys along the past light cone out to z = 0.7 (8 from the HR2 and 27 from the HR3), to simulate the BOSS geometry. The simulations and mock surveys are already publicly available at http://astro.kias.re.kr/Horizon-Run23/.
        5,200원
        20.
        2011.11 KCI 등재 구독 인증기관·개인회원 무료
        몇 십년 전만해도, 피해자가 통지를 받고, 출석하여, 진술할 수 있는 법적 권리는 거의 형사사법 체계내에서 없었다. 피해자는 재판 절차 또는 피고인의 체포나 석방에 대해 고지될 필요가 없었으므로, 그들은 재판이나 다른 절차에 출석할 권리가 없었고, 형의 선고나 기타 심리를 위해 법정에서 진술할 권리도 없었다. 더욱이, 피해자 지원 프로그램은 사실상 없는 것이나 마찬가지였다. 그 이후로, 범죄피해자의 법적인 권리를 창설하고 지원하는 프로그램에서 놀라운 진전이 있었다. 오늘날, 캘리포니아와 대부분의 다른 주는 실정법 내에 범죄피해자의 기본적인 권리와 보호를 위한 광범위한 규정체계를 가지고 있다. 피해자 권리규정은 연방, 주, 지방 형사사법제도 차원에서 피해자를 대하는 태도에 중대한 영향을 미쳤다.
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