• 유기물자원화
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• 제22권1호
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• pp.35-39
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• 2014

세계는 지속가능개발에 대한 관심을 가져왔고, 지속가능의 3가지 가치(환경보전성, 경제성장성, 사회발전성)를 중요시 여겼다. Rio+20 회담은 "녹색경제"에 대해 주목하고 지속가능개발을 위한 방안을 모색하려 했지만, 결론적으로 Rio+20에서 제시한 "The Future We Want"에 대한 답을 찾지 못하여 많은 아쉬움을 가지고 있다. 또한 지속가능개발의 3가지 가치만으로는 지속적인 발전에 한계가 있다고 판단되고, "The Future We Want"에 대한 해답과 지속가능개발의 발전을 위한 방안으로써 5가지 가치 즉, 녹색별(환경보전성, 경제성장성, 사회발전성, 과학기술성, 자율자발성)을 제안한다. 그리고 4대강사업의 결과를 녹색별로 검증함으로써 녹색별 모델을 지속가능발전을 위한 새로운 패러다임으로 제시하고, 대한민국의 안녕강국을 기대한다.

• 한국게임학회 논문지
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• 제20권6호
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• pp.13-22
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• 2020

RIO는 윈도우의 최신 네트워크 API로 낮은 부하와 지연을 통해 높은 IO 성능을 발휘하도록 설계되었으며. 고성능의 네트워크 IO를 요구하는 대규모 동시접속(MMO) 게임 서버에 적합할 것으로 기대된다. 또한 HTM은 기존의 멀티스레드 동기화 방식보다 생산성과 성능이 우수하여 MMO 게임 서버에 적용 시 성능향상이 예상된다. 본 논문에서는 MMO 게임 서버에 RIO를 적용함과 동시에 RIO의 성능을 최대한 끌어내도록 구조를 개선하고, 기존의 시야 처리 알고리즘을 HTM 방식으로 변경하여 서버의 성능을 향상시켰다. 결과적으로 동시 접속자 수를 19%가량 증가시켰으며, 벤치마킹 프로그램을 사용하여 이를 검증하였다.

• Restorative Dentistry and Endodontics
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• 제48권4호
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• pp.37.1-37.17
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• 2023

This study aimed to compare the disinfectant ability of chlorhexidine (CHX) gel and sodium hypochlorite (NaOCl). Systematic searches were conducted from inception until December 8th, 2022 (MEDLINE/PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Grey Literature databases). Only randomized clinical trials were included. The revised Cochrane risk of bias tools for randomized trials were used to assess the quality of studies. Meta-analyses were performed. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation tool. Six studies were included. Five had a low risk of bias and 1 had some concerns. Three studies assessed bacterial reduction. Two were included in the meta-analysis for bacterial reduction (mean difference, 75.03 [confidence interval, CI, -271.15, 421.22], p = 0.67; I² = 74%); and 3 in the meta-analysis for cultivable bacteria after chemomechanical preparation (odds ratio, 1.03 [CI, 0.20, 5.31], P = 0.98; I² = 49%). Five studies assessed endotoxin reduction. Three were included in a meta-analysis (mean difference, 20.59 [CI, -36.41, 77.59], p = 0.48; I² = 74%). There seems to be no difference in the disinfectant ability of CHX gel and NaOCl, but further research is necessary.

• ALGAE
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• 제33권1호
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• pp.85-99
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• 2018

Crustose calcareous algae (CCA) constitute one of the main reef builders on the Abrolhos Bank, Brazil. Once CCA taxonomy is locally understood, differences in growth-forms may be useful for the delimitation of taxa using characteristics such as the presence or absence of surface protuberances. Here, growth-forms were used to identify and quantify the most common CCA taxa on the shallow reefs (3-10 m) of the Abrolhos Bank to determine possible changes in the CCA community over a period of 10 years, and the ecological significance of CCA to local reefs was interpreted. The CCA assemblages were surveyed from 2006-2015 by using fixed photoquadrats at four sites in the inner (10-20 km from the mainland) and mid-shelf reefs (40-75 km from the mainland). The five most common CCA taxa were Pneophyllum conicum, the Lithophyllum kaiserii / Lithophyllum sp. complex, Melyvonnea erubescens, the Hydrolithon boergesenii / Porolithon onkodes complex and Peyssonelia sp. The overall mean CCA cover on the reefs was 20%. A comparison with a previous monitoring study in the same region indicated that the CCA cover nearly doubled from 2003-2008 to 2006-2015. This study reveals that the coral-killing species P. conicum dominated CCA flora on the shallow Abrolhos reefs in the last decade, and the local specific abundance of CCA slightly fluctuated over time and was species- and site-specific. The information obtained in this study contributes to the understanding of the ecology of the key calcifying components of the Abrolhos reefs and provides a useful baseline for exploring the responses of CCA to future environmental changes.

• Advances in concrete construction
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• 제14권1호
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• pp.1-13
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• 2022

Due to the physical-chemical characteristics of some bottom ash (BA), there are technical, economic and environmental limitations to find a destination that will add value to it. In Brazil, this residue is eventually used for filling coal extraction pits or remains in sedimentation ponds, creating a susceptible panorama to environmental issues. The geopolymers binders are one of the alternatives to the proper use high amounts of these materials. In this work, geopolymeric binder pastes were produced with BA mixed to activators with different alkali contents (expressed as %Na₂O), as well as the incorporation of soluble silicates (Ms content). The production of binary geopolymeric pastes based on the use of two industrial wastes: fluid catalytic cracking (FCC) and aluminum anodizing sludge (AAS), was also assessed. The content in mass of BA/FCC and BA/AAS ranged from 100/0, 90/10; 80/20 and 70/30. Systems with soluble silicates as activator in a molar ratio SiO₂/Na₂O of 1.0 (Ms = 1.0) and Na₂O content of 15%, showed the best results of mechanical strength (42 MPa at day 28^th). The improvement is up to 5X when compared to NaOH based systems. For systems with partial replacement of BA of 10% of AAS and 20% of FCC (80/20), the presence of soluble silicates was also effective to increase compressive strength.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1862-1867
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• 2006

A moderately halophilic, Gram-positive, spore-forming bacterium was isolated from the roots of Blutaparon portulacoides, a plant found in sandy soil parallel to the beach line in Restinga de Jurubatiba, Rio de Janeiro, Brazil. The strain, designated $M9^T$, was motile and strictly aerobic with rod-shaped cells. It grew in the absence of NaCl and up to 20% NaCl, and was able to hydrolyze casein and starch. Strain $M9^T$ had a cell-wall peptidoglycan based on L-Orn-D-Asp, the predominant menaquinone present was menaquinone-7 (MK-7), diaminopimelic acid was not found, and anteiso-$C_{15:0}$ and iso-$C_{15:0}$ were the major fatty acids. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain $M9^T$ belonged to the genus Halobacillus and exhibited 16S rRNA gene similarity levels of 97.8-99.4% with the type strains of the other nine Halobacillus species. The DNA-DNA relatedness of strain $M9^T$ with H. trueperi, the closest relative as regards 16S rRNA gene similarity, and H. locisalis was 21% and 18%, respectively. Therefore, on the basis of phenotypic, genotypic, and phylogenetic data, strain $M9^T$ (=ATCC BAA-$1217^T$, =CIP $108771^T$, =KCTC $3980^T$) should be placed in the genus Halobacillus as a member of a novel species, for which the name Halobacillus blutaparonensis sp. nov. is proposed.

• Computers and Concrete
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• 제20권3호
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• pp.319-327
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• 2017

Studying the structural behavior of prestressed segmented girders is quite important due to the large use this type of solution in viaducts and bridges. Thus, this work presents a nonlinear three-dimensional structural analysis of an externally prestressed segmented concrete girder through the Finite Element Method (FEM), using a customized ANSYS platform, version 14.5. Aiming the minimization of the computational effort by using the lowest number of finite elements, a new viscoelastoplastic material model has been implemented for the structural concrete with the UPF customization tool of ANSYS, adding new subroutines, written in FORTRAN programming language, to the main program. This model takes into consideration the cracking of concrete in its formulation, being based on fib Model Code 2010, which uses Ottosen rupture surface as the rupture criterion. By implementing this new material model, it was possible to use the three-dimensional 20-node quadratic element SOLID186 to model the concrete. Upon validation of the model, an externally prestressed segmented box concrete girder that was originally lab tested by Aparicio et al. (2002) has been computationally simulated. In the discretization of the structure, in addition to element SOLID186 for the concrete, unidimensional element LINK180 has been used to model the prestressing tendons, as well as contact elements CONTA174 and TARGE170 to simulate the dry joints along the segmented girder. Stresses in the concrete and in the prestressing tendons are assessed, as well as joint openings and load versus deflection diagrams. A comparison between numerical and experimental data is also presented, showing a good agreement.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.818-825
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• 2012

Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support ($q_m$) and dissociation constant ($K_d$) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at $65^{\circ}C$. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.

• Coupled systems mechanics
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• 제8권2호
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• pp.169-184
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• 2019

This research work presents a study that aims to assess the dynamic structural behaviour and also investigate the human comfort levels of a reinforced concrete building, when subjected to nondeterministic wind dynamic loadings, considering the effect of masonry infills on the global stiffness of the structural model. In general, the masonry fills most of the empty areas within the structural frames of the buildings. Although these masonry infills present structural stiffness, the common practice of engineers is to adopt them as static loads, disregarding the effect of the masonry infills on the global stiffness of the structural system. This way, in this study a numerical model based on sixteen-storey reinforced concrete building with 48 m high and dimensions of $14.20m{\times}15m$ was analysed. This way, static, modal and dynamic analyses were carried out in order to simulate the structural model based on two different strategies: no masonry infills and masonry infills simulated by shell finite elements. In this investigation, the wind action is considered as a nondeterministic process with unstable properties and also random characteristics. The fluctuating parcel of the wind is decomposed into a finite number of harmonic functions proportional to the structure resonant frequency with phase angles randomly determined. The nondeterministic dynamic analysis clearly demonstrates the relevance of a more realistic numerical modelling of the masonry infills, due to the modifications on the global structural stiffness of the building. The maximum displacements and peak accelerations values were reduced when the effect of the masonry infills (structural stiffness) were considered in the dynamic analysis. Finally, it can be concluded that the human comfort evaluation of the sixteen-storey reinforced concrete building can be altered in a favourable way to design.

• Restorative Dentistry and Endodontics
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• 제47권1호
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• pp.13.1-13.13
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• 2022

Objectives: This study evaluated the efficacy of 3 reciprocating systems and the effects of 2 instruments for irrigant activation on filling material removal. Materials and Methods: Forty mesiobuccal roots of maxillary molars were prepared up to size 25.06 and obturated. Micro-computed tomography (micro-CT) examination #1 was performed. Teeth were then divided into 4 groups (n = 10), according to the retreatment protocol: (1) manual, (2) Reciproc Blue, (3) WaveOne Gold, and (4) X1 Blue. Micro-CT examinations #2 and #3 were performed after filling removal and repreparation, respectively. Next, all teeth were divided into 2 new groups (n = 20) according to the irrigant activation protocol: XP Clean (XP Clean size 25.02) and Flatsonic (Flatsonic ultrasonic tip). Micro-CT examination #4 was performed after irrigant activation. Statistical analysis was performed with a significance level set at 5%. Results: WaveOne Gold removed a significantly greater amount of filling material than the manual group (p < 0.05). The time to reach the WL was similar for all reciprocating systems (p > 0.05). X1 Blue was faster than the manual group (p < 0.05). Only manual group improved the filling material removal after the repreparation stage (p < 0.05). Both activation protocols significantly improved the filling material removal (p < 0.05), without differences between them (p > 0.05). Conclusions: None of the tested instruments completely removed the filling material. X1 Blue size 25.06 reached the working length in the shortest time. XP Clean and Flatsonic improved the filling material removal.