• Title/Summary/Keyword: Separation resistance

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Race and Politics in Brazil: Occurrence, Development, Characteristics (브라질의 인종과 정치: 발생, 전개, 특징)

  • Kim, Dal-Kwan
    • Iberoamérica
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    • v.21 no.1
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    • pp.1-55
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    • 2019
  • In Brazil, racism exists without the clear definition of race. In other words, because there is racism without a clear concept of race, racial issues are complicated in Brazil. Racism is not just a social problem. It is, above all, a political problem that arises from economic separation, exclusion, and marginalization. From the enlargement process of European colonialism, racism has been the most profound and efficient way of governance of social, material, psychological and political domination of Brazil. From this perspective, this study seeks to research racism in Brazil as a race politics. In conclusion, racial discrimination and racial inequality exist in Brazil. Thus, to study the racial discrimination and racial inequalities in Brazil, Chapter 2 examines the origins of racial politics in Brazil. Chapter 3 explores the relations of Brazilian society and races. Chapter 4 examines Black's resistance to racism as a black movement in Brazil. The first half of Chapter 5 looks at 'racial inequality in Brazil' and the latter sees 'racism in Brazil'. Chapter 6, as a conclusion, discusses the challenges and limitations of racial politics in Brazil.

Fabrication of Porous Cellulose Acetate Propionate/Polybutylene Succinate Microfibers by High Speed Centrifugal Spinning (초고속 원심방사에 의한 아세트산프로피온산 셀룰로오스/폴리부틸렌 숙시네이트 다공성 마이크론 섬유 제조)

  • Tae Young Kim;Mi Kyung Kim;Jinsoo Kim;Jungeon Lee;Jae Hoon Jung;Youngkwon Kim;Tae Hyeon Kim;Ki Young Kim;Jeong Hyun Yeum
    • Textile Coloration and Finishing
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    • v.35 no.4
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    • pp.239-245
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    • 2023
  • Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.

IL-34 Aggravates Steroid-Induced Osteonecrosis of the Femoral Head via Promoting Osteoclast Differentiation

  • Feng Wang;Hong Sung Min;Haojie Shan;Fuli Yin;Chaolai Jiang;Yang Zong;Xin Ma;Yiwei Lin;Zubin Zhou;Xiaowei Yu
    • IMMUNE NETWORK
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    • v.22 no.3
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    • pp.25.1-25.11
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    • 2022
  • IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

Perfluoropolymer Membranes of Tetrafluoroethylene and 2,2,4Trifluofo- 5Trifluorometoxy- 1,3Dioxole.

  • Arcella, V.;Colaianna, P.;Brinati, G.;Gordano, A.;Clarizia, G.;Tocci, E.;Drioli, E.
    • Proceedings of the Membrane Society of Korea Conference
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    • 1999.07a
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    • pp.39-42
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    • 1999
  • Perfluoropolymers represent the ultimate resistance to hostile chemical environments and high service temperature, attributed to the presence of fluorine in the polymer backbone, i.e. to the high bond energy of C-F and C-C bonds of fluorocarbons. Copolymers of Tetrafluoroethylene (TEE) and 2, 2, 4Trifluoro-5Trifluorometoxy- 1, 3Dioxole (TTD), commercially known as HYFLON AD, are amorphous perfluoropolymers with glass transition temperature (Tg)higher than room temperature, showing a thermal decomposition temperature exceeding 40$0^{\circ}C$. These polymer systems are highly soluble in fluorinated solvents, with low solution viscosities. This property allows the preparation of self-supported and composite membranes with desired membrane thickness. Symmetric and asymmetric perfluoropolymer membranes, made with HYFLON AD, have been prepared and evaluated. Porous and not porous symmetric membranes have been obtained by solvent evaporation with various processing conditions. Asymmetric membranes have been prepared by th wet phase inversion method. Measure of contact angle to distilled water have been carried out. Figure 1 compares experimental results with those of other commercial membranes. Contact angles of about 120$^{\circ}$for our amorphous perfluoropolymer membranes demonstrate that they posses a high hydrophobic character. Measure of contact angles to hexandecane have been also carried out to evaluate the organophobic character. Rsults are reported in Figure 2. The observed strong organophobicity leads to excellent fouling resistance and inertness. Porous membranes with pore size between 30 and 80 nanometers have shown no permeation to water at pressures as high as 10 bars. However high permeation to gases, such as O2, N2 and CO2, and no selectivities were observed. Considering the porous structure of the membrane, this behavior was expected. In consideration of the above properties, possible useful uses in th field of gas- liquid separations are envisaged for these membranes. A particularly promising application is in the field of membrane contactors, equipments in which membranes are used to improve mass transfer coefficients in respect to traditional extraction and absorption processes. Gas permeation properties have been evaluated for asymmetric membranes and composite symmetric ones. Experimental permselectivity values, obtained at different pressure differences, to various single gases are reported in Tab. 1, 2 and 3. Experimental data have been compared with literature data obtained with membranes made with different amorphous perfluoropolymer systems, such as copolymers of Perfluoro2, 2dimethyl dioxole (PDD) and Tetrafluorethylene, commercialized by the Du Pont Company with the trade name of Teflon AF. An interesting linear relationship between permeability and the glass transition temperature of the polymer constituting the membrane has been observed. Results are descussed in terms of polymer chain structure, which affects the presence of voids at molecular scale and their size distribution. Molecular Dyanmics studies are in progress in order to support the understanding of these results. A modified Theodoru- Suter method provided by the Amorphous Cell module of InsightII/Discover was used to determine the chain packing. A completely amorphous polymer box of about 3.5 nm was considered. Last but not least the use of amorphous perfluoropolymer membranes appears to be ideal when separation processes have to be performed in hostile environments, i.e. high temperatures and aggressive non-aqueous media, such as chemicals and solvents. In these cases Hyflon AD membranes can exploit the outstanding resistance of perfluoropolymers.

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The Origin and Formation of Korean Public Art Theories in the 1980s (1980년대 민중미술론의 기원과 형성)

  • Choi, Youl
    • The Journal of Art Theory & Practice
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    • no.7
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    • pp.37-64
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    • 2009
  • The theories of Korean Public Art originated by the artists who were against dictatorship and they associated with democratic politicians. They criticized the Fine art that were supported by the dictatorship and gave their efforts for restoration of 'resistance paintings(against dictatorship)', 'proletarian painting', 'realism painting'. In addition, they participated new social ideology(democracy) movement and demonstrated for their rights in arts. These became the main kernel the public art theory was initiated. The public artists splitted into several different parts and participated in the democratic social movement as well as the art movement for freedom. They opened various art exhibitions within different genre, diverse space for various art section such as an exhibition hall, a factories, a university, or a congregation square. Furthermore, the public art theorists published their divergent views through newspaper/broadcasting or unauthorized printed materials. Most of the public artist and the theorists kept their relationship strongly until 1985, the time when 'National Arts Association' started. In 1983 and 1984, they were clearly separated into two parts; artists(move only in art museums) and activists(move in public spaces like school, convention square etc). Their ideological separation also took out national problems. The division; professional artists and armatures, became the social issue as a social stratification matter. And in creating method, there are also other conflicts; critical realism, and public realism as well as western painting and traditional one. These kinds of separation and conflicts made different Public artists associations, under divergent names; 'Reality and Speak'(R&S), 'KwangJu Art Association', 'Durung', 'Dang(Land)', and 'Local Youth Students Association'. In addition, their ideology and pursuit toward art movements were very difference. However, the differences and conflicts weakened When the oppression of democratic education from new dictatorship(Pres. Jun, Doo Hwan) came out. In August. 1985 the government opened to the public so called, 'The draft of School stabilization law'(Hankwon Anjung Bup) to control the teachers' rights and that initiated bigger street demonstration and conflicts between police and educators. In November.1985, assembly meeting of National Arts Association in democracy opened as 'ONE' combined organization. In this presentation, I'd like to summarize the stream of art movement until 1984, and clarify the main art theories that lead the Public Art Movements in 1980s. The main theories in 1980s are crucial because they become the origin of public art theories. This presentation started with O,youn's "Hyunsil Dong In the first declaration" and explained the absent of practice in 1970s. In addition, Won, Dong Suk 's theory was mentioned as all over struggles in theories before 1980s. GA and R&S 's founding declarations in 1970s were the start of public art theorists' activities and this article reported the activities after the declarations. First, realism base on the consciousness of reality. Second, practice art democratization based on the ideology. Third, the subject of public art movement based on understanding people's social stratification structure. Fourth, the matters of national forms and creative ways in arts based on showing reality. Fifth, the strong points in arts that the practitioners accepted. About the public art theories around 1984, I discussed the dividing point of public art theories that were shown in 'generation theory', 'organization theory', and 'popularization theory' by the practitioners. The public realism theory that subjects the contradiction of reality and point out the limits of critical realism not only showing the new creative ways but also giving the feeling of solidarity to the public art activist groups. After that, public art movements expressed 'Dismentlement of Capitalism' and 'Public revolution'. In addition, the direction of public art movements were established strongly. There were various opinions and views during the start and formation of the public art theories. The foundation of theorists activities derived from the practitioners who had the concept based on stratification and nationalism. The strong trend of group division spreaded out by practitioners who opened art work together in factories, universities, squares and rural areas. Now many lively active practitioners are gone to the other field not related with arts, and others join into professional art field not public art one with unknown reason. The theorists have the same situation with the practitioners. It means to me that theory always have to be based on the practice.

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A Study of Spatiality, Placeness and Environmental Values for the Regional Instruction : A Case of Jinju Area (지역학습을 위한 공간성.장소성.환경가치의 연구: 진주지역의 사례)

  • Sim, Kwang-Taek
    • Journal of the Korean association of regional geographers
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    • v.11 no.5
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    • pp.349-367
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    • 2005
  • The purpose of this paper is to establish three themes of regional instruction based on new regional geography and to examine explanation of space, understanding of place and judgement of environmental values for the Jinju regional instruction. Under the premise that region is the representation of space, place, and environmental perception, we reviewed location and space, event and place, development and environmental values in Jinju area. The results of the study are as follows: Owing to locational conditions, commercial agriculture, industrial and agroindustrial park, bio industry have been developed in Jinju. There are however some tasks that have to be solved such as rural investment, industrial park relocation and economic reconstruction. The Jinju castle combat, Farmers' resistance in 1862, Human right campaign for butchers in 1923, and educational conflict all occurred in the Jinju community. These events resulted in the integration and separation of the stratified citizens. They were represented as a variety of semiotics and landscape in the place. Citizens who live in Jinju are confronted with judging the environmental values. They ask whether inviting companies to town will ensure environmentally sound and sustainable development. The regional characteristics of knowledge, culture and environment in Jinju have been reproduced through the economic activity, place understanding, place marketing, and citizens' campaign.

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Thermal Behavior of Energy Pile Considering Ground Thermal Conductivity and Thermal Interference Between Piles (주변 지반의 열전도도를 고려한 PHC 에너지파일의 열 거동 및 파일 간 열 간섭 현상에 대한 수치해석 연구)

  • Go, Gyu Hyun;Yoon, Seok;Park, Do Won;Lee, Seung-Rae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.6
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    • pp.2381-2391
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    • 2013
  • In general, ground's thermal properties, types of heat exchanger, operational method, thermal interference between piles can be considered as key factors which affect the thermal performance of energy pile. This study focused on the effect of these factors on the performance by a numerical model reflecting a real ground condition. Depending on the degree of saturation of ground, pile's heat transfer rate showed a maximum difference of three times, and the thermal resistance of pile made a maximum difference of 8.7%. As for the type of heat exchanger effects on thermal performance, thermal efficiency of 3U type energy pile had a higher value than those of W and U types. The periodic operation (8 hours operation, 16 hours pause) can preserve about 20% of heat efficiency compared to continuous operation, and hence it has an advantage of preventing the thermal accumulation phenomenon. Thermal interference effect in group piles may vary depending on the ground condition because the extent decreases as the ground condition varies from saturated to dry. The optimal separation distance that maintains the decreasing rate of heat efficiency less than 1% was suggested as 3.2D in U type, 3.6D in W type, and 3.7D in 3U type in a general ground condition.

Construction of hsf1 Knockout-mutant of a Thermotolerant Yeast Strain Saccharomyces cerevisiae KNU5377 (고온내성 연료용 알코올 효모균주 Saccharomyces cerevisiae KNU5377에서 HSF1 유전자의 변이주 구축)

  • Kim Il-Sup;Yun Hae-Sun;Choi Hye-Jin;Sohn Ho-Yong;Yu Choon-Bal;Kim Jong-Guk;Jin Ing-Nyol
    • Journal of Life Science
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    • v.16 no.3 s.76
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    • pp.454-458
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    • 2006
  • HSF1 is the heat shock transcription factor in Saccharomyces cerevisiae. S. cerevisiae KNU5377 can ferment at high temperature such as $40^{\b{o}}C$. We have been the subjects of intense study because Hsf1p mediates gene expression not only to heat shock, but to a variety of cellular and environmental stress challenges. Basing these facts, we firstly tried to construct the hsf1 gene-deleted mutant. PCR-method for fast production of gene disruption cassette was introduced in a thermotolerant yeast S. cerevisiae KNU5377, which allowed the addition of short flanking homology region as short as 45 bp suffice to mediate homologous recombination to kanMX module. Such a cassette is composed of linking genomic DNA of target gene to the selectable marker kanMX4 that confers geneticin (G418) resistance in yeast. That module is extensively used for PCR-based gene replacement of target gene in the laboratory strains. We describe here the generation of hsf1 gene disruption construction using PCR product of selectable marker with primers that provide homology to the hsf1 gene following separation of haploid strain in wild type yeast S. cerevisiae KNU5377. Yeast deletion overview containing replace cassette module, deletion mutant construction and strain confirmation in this study used Saccharomyces Genome Deletion Project (http:://www-sequence.standard.edu/group/yeast_deletion_project). This mutant by genetic manipulation of wild type yeast KNU5377 strain will provide a good system for analyzing the research of the molecular biology underlying their physiology and metabolic process under fermentation and improvement of their fermentative properties.

Preparation of diffusion dialysis membrane for acid recovery via a phase-inversion method

  • Khan, Muhammad Imran;Wu, Liang;Hossain, Md. Masem;Pan, Jiefeng;Ran, Jin;Mondal, Abhishek N.;Xu, Tongwen
    • Membrane and Water Treatment
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    • v.6 no.5
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    • pp.365-378
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    • 2015
  • Herein, the preparation of anion exchange membrane (AEM) from brominated poly(2,6-dimethyl 1,6-phenylene oxide) BPPO and dimethylaniline (DMA) by phase-inversion process is reported. Anion exchange membranes (AEMs) are prepared by varying the DMA contents. Prepared AEMs show high thermal stability, water uptake (WR) around 202% to 226%, dimensional change ratios of 1.5% to 2.6% and ion exchange capacities (IECs) of 0.34 mmol/g to 0.82 mmol/g with contact angle of $59.18^{\circ}$ to $65.15^{\circ}$. These membranes are porous in nature as confirmed by SEM observation. The porous property of membranes are important as it could reduce the resistance of transportation of ions across the membranes. They have been used in diffusion dialysis (DD) process for recovery of hydrochloric acid (HCl) from the mixture of HCl and ferrous chloride ($FeCl_2$). Presence of $-N+(CH_3)_2C_6H_5Br^-$ as a functional group in membrane matrix facilitates its applications in DD process. The dialysis coefficients of hydrochloric acid ($U_H$) of the membranes are in range of 0.0016 m/h to 0.14 m/h and the separation factors (S) are in range of 2.09 to 7.32 in the $HCl/FeCl_2$ system at room temperature. The porous membrane structure and presence of amine functional group are responsible for the mechanism of diffusion dialysis (DD).

A study on the fatigue bending strength of quasi-isotropic CFRP laminates subjected to impact damage (축격손상을 받은 의사등방성 탄소섬유강화 복합재의 굽힘피로강도)

  • Park, Soo-Chul;Park, Seol-Hyeon;Jung, Jong-An;Cha, Cheon-Seok;Yang, Yong-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.688-695
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    • 2017
  • Compared to metal, CFRP has excellent mechanical characteristics in terms of intensity, hardness, and heat resistance as well as its light weight that it is used widely in various fields. Therefore, this material has been used recently in the aerospace field. On the other hand, the material has shortcomings in terms of its extreme vulnerability to damage occurring internally from an external impact. This study examined the intensity up to its destruction from repeated use with the internal impact of a CFRP laminated plate that had also been exposed to external impact obtain design data for the external plate of aircraft used in the aerospace field. For the experimental method, regarding the quasi-isotopic type CFRP specimen and orthotropic CFRP specimen that are produced with a different layer structure, steel spheres with a diameter of 5 mm were collided to observe the resulting impact damage. Through a 3-point flexural fatigue experiment, the progress of internal layer separation and impact damage was observed. Measurements of the flexural fatigue strength after the flexural fatigue experiment until internal damage occurs and the surface impacted by the steel spheres revealed the quasi-isotopic layer structure to have a higher intensity for both cases.