• Title/Summary/Keyword: lead segregation

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Determinants of Economic Segregation and Spatial Distribution of Poverty

  • Park, Yoonhwan
    • Journal of Distribution Science
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    • v.17 no.3
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    • pp.21-30
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    • 2019
  • Purpose - While many related prior studies have focused on the segregation by race and ethnicity, the academic interest in the separation of residence by income and social class is gradually increasing. This study aims to not only investigate spatial pattern of economic segregation and poverty rate in South Korea, but also shed light on what affect residential distribution of the poor. Research design, data, and methodology - The unit of analysis is Si-Gun-Gu municipal level entities of South Korea. Most demographic, socioeconomic, and residential variables were derived from Korean Census Data in 2015. In order to examine spatial patterns of economic segregation and poverty rate in South Korea, a series of measurements and visualization was conducted through the Geo-Segregation Analyzer and ArcGIS programs. Determinants of economic segregation and local poverty rates were investigated by regression analyses using STATA. Results - The spatial patterns of areas with high poverty rates were extremely clustered, while the distribution of areas with high economic segregation was relatively evenly distributed. Demographic, residential, and local factors appeared to affect whether the poor live in particular area or spread evenly. Conclusions - The factors that raise the poverty rate result in lower level of economic segregation, while factors that reduce the poverty rate lead to severe level of economic segregation.

Historical Implications of Residential Segregation in Busan, Korea (부산시 거주공간분화의 시대사적 함의)

  • Bae, Mi-Ae
    • Journal of the Korean association of regional geographers
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    • v.13 no.5
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    • pp.477-494
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    • 2007
  • This paper offers a brief overview of the historical implications of residential segregation in Busan, Korea. It first reviews the history of residence from the early 1900s to the present and the transition of residential boundary of the City of Busan. It then considers the characteristics of residential segregation and the important factors in it. The social class of pre-industrial society led the inequality of residential areas around the Eubchee. The existed Korean residential areas were separated by newly built-up residential areas in the Japanese colonial era. After the liberation from Japanese Rule and Korean War, rapid population growth made considerable slums across the City of Busan. These slums were an important factor to segregate residential areas from prosperous areas ever afterward. The socio-economic status has related to residential segregation through the formation of differential housing classes since 1990s. The historial analysis of these periods will offer an insight into how the dominant factors lead residential segregation in a specific period by promoting a more socio-economically integrated society.

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황동볼트 손상원인 분석사례

  • Jeong, Nam-Geun
    • 열병합발전
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    • s.30
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    • pp.21-25
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    • 2002
  • According to recent Korea Electric Power Company report, yearly distribution line brass cramp bolts failure summed up to 4,400 cases emerging as one of main local break-down causes. Naturally, the need for the investigation was proposed To determine the root cause of the cramp bolt failures, mechanical and metallurgical investigation were performed for 90 samples which collected from various sites. For the understanding of the geometric characteristics, stress distribution was evaluated by CAE program and proof load of each bolts was tested. The SEM&EDS was used for metallurgical investigation. Through the investigation, the root causes of failures were confirmed. All damaged bolts showed intergrannular fracture mode and the all fractured bolt showed ß phase morphology contrast to the a&ß mixture morphology of the non-damaged samples. Additionally, EDS analysis confirmed the existence of lead rich layer on grain boundaries.

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Atomic-resolution Transmission Electron Microscopy Investigation of η2 Precipitate Growth in Al-Zn-Mg Alloy (원자단위 투과전자현미경을 활용한 알루미늄-아연-마그네슘 합금 내부 η2 석출물 성장 메커니즘 규명)

  • H. Kim;H. N. Han
    • Transactions of Materials Processing
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    • v.33 no.1
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    • pp.12-17
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    • 2024
  • Aluminum-zinc-magnesium alloy is a well-known alloy that is both strong and lightweight. Precipitation strengthening plays a significant role in the strength mechanism of this alloy, with nano-sized η-based precipitates being the representative precipitates. However, the growth of η precipitates can lead to a decrease in strength, necessitating research into ways to control their growth. In this study, we observed the atomic-level behavior of η2 precipitates and discovered that the precipitates grew through a combination with magnesium after a zinc segregation layer was formed around them.

Cloning and Functional Characterization of Ptpcd2 as a Novel Cell Cycle Related Protein Tyrosine Phosphatase that Regulates Mitotic Exit

  • Zineldeen, Doaa H.;Wagih, Ayman A.;Nakanishi, Makoto
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.6
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    • pp.3669-3676
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    • 2013
  • Faithful transmission of genetic information depends on accurate chromosome segregation as cells exit from mitosis, and errors in chromosomal segregation are catastrophic and may lead to aneuploidy which is the hallmark of cancer. In eukaryotes, an elaborate molecular control system ensures proper orchestration of events at mitotic exit. Phosphorylation of specific tyrosyl residues is a major control mechanism for cellular proliferation and the activities of protein tyrosine kinases and phosphatases must be integrated. Although mitotic kinases are well characterized, phosphatases involved in mitosis remain largely elusive. Here we identify a novel variant of mouse protein tyrosine phosphatase containing domain 1 (Ptpcd1), that we named Ptpcd2. Ptpcd1 is a Cdc14 related centrosomal phosphatase. Our newly identified Ptpcd2 shared a significant homology to yeast Cdc14p (34.1%) and other Cdc14 family of phosphatases. By subcellular fractionation Ptpcd2 was found to be enriched in the cytoplasm and nuclear pellets with catalytic phosphatase activity. By means of immunofluorescence, Ptpcd2 was spatiotemporally regulated in a cell cycle dependent manner with cytoplasmic abundance during mitosis, followed by nuclear localization during interphase. Overexpression of Ptpcd2 induced mitotic exit with decreased levels of some mitotic markers. Moreover, Ptpcd2 failed to colocalize with the centrosomal marker ${\gamma}$-tubulin, suggesting it as a non-centrosomal protein. Taken together, Ptpcd2 phosphatase appears a non-centrosomal variant of Ptpcd1 with probable mitotic functions. The identification of this new phosphatase suggests the existence of an interacting phosphatase network that controls mammalian mitosis and provides new drug targets for anticancer modalities.

Provenance and Microstructures of an Ancient Korean Bronze Dagger (한국(韓國) 세형동검(細形銅劍)의 미세구조(微細構造) 및 원료산지(原料産地) 추정(推定))

  • Choi, Ju;Do, Jung Man;Kim, Soo Chul;Kim, Sun Tae;Eom, Tae Yoon;Kim, Jung-Bae
    • Analytical Science and Technology
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    • v.5 no.2
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    • pp.191-197
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    • 1992
  • An ancient Korean bronze dagger excavated from Yongjai-ri, Iksan-kun, presumed to be manufactured in the pre-historical age, was examined by means of chemical analysis, energy dispersive spectrometry, optical and scanning electron microscopy. Also the measurement of lead isotope ratios was carried out in order to predict the site where raw materials were produced. The composition was identified as 75.3% Cu, 17.1% Sn and 6.8% Pb which was a typical composition of Korean bronze dagger. The microstructure was consisted of ${\alpha}$ and (${\alpha}+{\delta}$) eutectoid. The (${\alpha}+{\delta}$) eutectoid can be easily corroded in comparison with ${\alpha}$. The segregation was frequently observed in the interior of the sample. According to the lead isotopes ratios, raw materials have possibility to be from North China.

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Compressive strength and mixture proportions of self-compacting light weight concrete

  • Vakhshouri, Behnam;Nejadi, Shami
    • Computers and Concrete
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    • v.19 no.5
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    • pp.555-566
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    • 2017
  • Recently some efforts have been performed to combine the advantages of light-weight and self-compacting concrete in one package called Light-Weight Self-Compacting Concrete (LWSCC). Accurate prediction of hardened properties from fresh state characteristics is vital in design of concrete structures. Considering the lack of references in mixture design of LWSCC, investigating the proper mixture components and their effects on mechanical properties of LWSCC can lead to a reliable basis for its application in construction industry. This study utilizes wide range of existing data of LWSCC mixtures to study the individual and combined effects of the components on the compressive strength. From sensitivity of compressive strength to the proportions and interaction of the components, two equations are proposed to estimate the LWSCC compressive strength. Predicted values of the equations are in good agreement with the experimental data. Application of lightweight aggregate to reduce the density of LWSCC may bring some mixing problems like segregation. Reaching a higher strength by lowered density is a challenging problem that is investigated as well. The results show that, the compressive strength can be improved by increasing the of mixture density of LWSCC, especially in the range of density under $2000Kg/m^3$.

Metal Recycling Technologies from Fly-Ashes by the Metal Mining Agency of Japan

  • Kazuyuki, Kikuta;Nobuyuki, Masuda;Nobuyuki, Okamoto;Eiichi, Arai;Junichi, Kobayashi
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.659-663
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    • 2001
  • In Japan, the municipal solid waste, which amounts to 50 million tons, is generated every year and most of it is incinerated. The bottom and fly ashes are disposed to the registered disposal areas under the provisions of The Waste Disposal and Public Cleaning Law. Especially, as the fly ash from the municipal waste incineration (the primary fly ash) contains heavy metals (lead, zinc, etc) and dioxins, it cannot be disposed directly without decontamination, such as moiling, cementation, chelating and dissolving processes provided in the law. However, these procedures for decontamination, except melting, are not enough for dioxins. Even in case of melting, the fly ash from the process (the secondary fly ash) contains high concentration of heavy metals (e.g., Zn; 1-20%, Pb; 1-10%). For these reasons, Metal Mining Agency of Japan (MMAJ), a governmental organization, started a four-year project to develop the treatment technologies of these fly ashes in 1999. The purpose of the project is to establish the integrated technologies to recover the valuable metals from, and to decontaminate, the primary and secondary fly-ashes in the practical scale by utilizing the existing metallurgical processes and facilities, along with the energy saving and the reduction of the environmental impact.

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Inheritance of Apiculus Color, Awn, and Long Empty Glume in Korean Rice Collection

  • Kang, Hee-Kyoung
    • Plant Resources
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    • v.6 no.2
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    • pp.98-101
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    • 2003
  • Colored apiculus, awn, and long empty glume are indicators of wildness and are usually eliminated during rice domestication. Genetic analysis was conducted to clarify the inheritance patterns of awn, apiculus color, and long empty glume in Korean rice collection. Based on individual characterization of F$_2$ progenies derived from crosses between parents with colorless and purple apiculus, two (3 colored: 1 colorless) or three dominant genes (9 purple: 3 red: 4 colorless) are estimated as controlling this character by simultaneous complementary action. Different inheritance systems were detected between S237 and S245 of 'Shareibyeo' which belong to the weedy type. To determine the genes responsible in awning and long empty glume characters, the inheritance of landrace varieties of rice ('Naengdo' and 'Yuna') was investigated. In the crosses of awned land race and awnless cultivar, three dominant genes are supposed to control the awning genetic system by 63 awned: 1 awnless individual. As for long empty glume, one recessive gene, g-l on the chromosome 4, was the one controlling the segregation ratio of 3 normal empty: 1 long empty glume. By analyzing the Korean rice collection, the inheritance systems of these wild characters may lead to a better understanding of rice domestication in the future.

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Effect of silica fume and polyepoxide-based polymer on electrical resistivity, mechanical properties, and ultrasonic response of SCLC

  • Mazloom, Moosa;Allahabadi, Ali;Karamloo, Mohammad
    • Advances in concrete construction
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    • v.5 no.6
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    • pp.587-611
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    • 2017
  • This study focused on the influences regarding the use of polyepoxide-based polymer and silica fume (SF) on the fresh and hardened state properties of self-compacting lightweight concrete (SCLC) along with their impacts on electrical resistance and ultrasonic pulse velocity (UPV). To do so, two series of compositions each of which consists of twelve mixes, with water to binder (W/B) ratios of 0.35 and 0.4 were cast. Three different silica fume/binder ratios of 0, 5%, and 10% were considered along with four different polymer/binder ratios of 0, 5%, 10%, and 15%. Afterwards, the rupture modulus, tensile strength, 14-day, 28-day, and 90-day compressive strength, the UPV and the electrical resistance of the mixes were tested. The results indicated that although the use of polymer could enhance the passing and filling abilities, it could lead to a decrease of segregation resistance. In addition, the interaction of the SF and the polymeric contents enhanced the workability. However, the impacts regarding the use of polymeric contents on fresh state properties of SCLC were more prevalent than those regarding the use of SF. Besides the fresh state properties, the durability and mechanical properties of the mixes were affected due to the use of polymeric and SF contents. In other words, the use of the SF and the polymer enhanced the durability and mechanical properties of SCLC specimens.