• Title/Summary/Keyword: CSA

Search Result 521, Processing Time 0.024 seconds

The Engineering Properties of High Fluidity mortar with High Volume Slag Cement (고유동 대량치환 슬래그 모르타르의 공학적 특성)

  • Bae, Ju-Ryong;Kim, Tae-Wan;Kim, In-Tae;Kim, Min-Jeong
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.5
    • /
    • pp.12-20
    • /
    • 2017
  • This report presents the results of an investigation on the fundamental properties of mortars high fluidity high volume slag cement(HVSC) activated with sodium silicate($Na_2SiO_3$). The ordinary Portland cement(OPC) was replaced by ground granulated blast furnace slag(GGBFS) from 40% to 80% and calcium sulfoaluminate(CSA) was 2.5% or 5.0% mass. The $Na_2SiO_3$ was added at 2% and 4% by total binder(OPC+GGBFS+CSA) weight. A constant water-to-binder ratio(w/b)=0.35 was used for all mixtures. The research carried out the mini slump, V-funnel, setting time, compressive strength and drying shrinkage. The experimental results showed that the contents of superplasticizer, V-funnel, setting time and drying shrinkage increased as the contents of CSA and $Na_2SiO_3$ increase. The compressive strength increases with and an increase in CSA and $Na_2SiO_3$. One of the major reason for these results is the accelerated reactivity of GGBFS with CSA and $Na_2SiO_3$. The maximum performance was CSA 5.0% + $Na_2SiO_3$ 4% specimens.

Thermal and Electrical Behaviors of Polyethylene Oxide/Polyaniline Fibers Prepared by Electrospinning Method (전기방사법에 의해 제조된 폴리에틸렌옥사이드/폴리아닐린 섬유의 열적 및 전기적 거동)

  • Kim, Seok;Cho, Mi-Hwa;Park, Soo-Jin
    • Applied Chemistry for Engineering
    • /
    • v.17 no.1
    • /
    • pp.16-21
    • /
    • 2006
  • In this study, PEO blend fibers mixed with polyaniline (PANI)/10-camphor sulfonic acid (CSA) and PANI/dodecylbenzene sulfonic acid (DBSA) were electro spun to investigate the influence of PANI content. CSA and DBSA were used as a functionalized doping acid having a bulky volume. PANI/PEO blend solution was prepared by dissolving PEO and PANI doped with CSA or DBSA. The thermal properties were measured by thermogravimetric analyzer (TGA). As a result, with increasing of the PANI content in PANI/CSA and PANI/DBSA, although initial decomposition temperature (IDT) was decreased, thermal stability was increased due to the increase of $A^*{\cdot}K^*$ and integral procedural decomposition temperature (IPDT). The electrical conductivities measured by the 4-probe method. The electric conductivity was increased with increasing of PANI content in PANI/CSA and PANI/DBSA. However, electrical conductivity did not change significantly beyond 30% content of PANI. From CV results, PANI/CSA showed the better defined peak shpae and higher peak current density compared to PANI/DBSA. This was probably related to the slightly higher electrical conductivity or better morphology for easy charge transfer in the case of PANI/CSA.

The Fundamental Properties of High Fluidity Mortar with Activated Ternary Blended Slag Cement (활성화된 삼성분계 고유동 모르타르의 기초특성)

  • Bae, Ju-Ryong;Kim, Tae-Wan;Kim, In-Tae;Kim, Hyoung-Seok
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.21 no.6
    • /
    • pp.74-82
    • /
    • 2017
  • This research presents the results of the strength and drying shrinkage properties to study the effect of ground granulated blast furnace slag(GGBFS), fly ash(FA) and calcium sulfoaluminate(CSA) for activated ternary blended slag cement. The activated ternary blended cement(ATBC) mortar were prepared having a constant water-cementitious materials ratios of 0.4. The GGBFS contents ratios of 100%, 80%, 70% and 60%, FA replacement ratios of 10%, 20%, 30% and 40%, CSA ratios of 0%, 10%, 20% and 30% were designed. The superplasticizer of polycarboxylate type were used. The activator was used of 10% sodium hydroxide(NaOH) + 10% sodium silicate($Na_2SiO_3$) by weight of binder. Test were conducted for mini slump, setting time, V-funnel, water absorption, compressive strength and drying shrinkage. According to the experimental results, the contents of superplasticizer, V-funnel and compressive strength increases with an increase in CSA contents for all mixtures. Moreover, the setting time, water absorption ratios and drying shrinkage ratio decrease with and increase in CSA. One of the major reason for the increase of strength and decrease of drying shrinkage is the accelerated reactivity of GGBFS with alkali activator and CSA. The CSA contents is the main parameter to explain the strength development and decreased drying shrinkage in the ATBC.

Evaluation of a Fabricated Charge Sensitive Amplifier for a Semiconductor Radiation Detector

  • Kim, Han-Soo;Ha, Jang-Ho;Park, Se-Hwan;Lee, Jae-Hyung;Lee, Cheol-Ho
    • Journal of Radiation Protection and Research
    • /
    • v.35 no.2
    • /
    • pp.81-84
    • /
    • 2010
  • A CSA(Charge Sensitive Amplifier) was designed and fabricated for application in a radiation detection system based on a semiconductor detector such as Si, SiC, CdZnTe and etc.. A fabricated hybrid.type CSA was evaluated by comparison with a commercially available CSA. A comparison was performed by using calculation of ENC (Equivalent Noise Charge) and by using energy resolutions of fabricated radiation detectors based on Si. In energy resolution comparison, a fabricated CSA showed almost the same performance compared with a commercial one. In this study, feasibility of a fabricated CSA was discussed.

중금속이 칼슘설포알루미네이트의 클링커 반응 및 에트링자이트 생성에 미치는 영향

  • 유광석;안지환;천성민;김환
    • Cement Symposium
    • /
    • no.32
    • /
    • pp.103-106
    • /
    • 2005
  • 유해 중금속을 다량 함유하고 있는 산업폐기물의 고화 처리에 사용되는 칼슘설포알루미네이트(4CaO$\cdot$$3Al_2O_3$$\cdot$$SO_4$이후부터 CSA로 기입) 의 제조를 위해 철강부산물인 압연 슬러지를 활용하여 그 특성에 대해 조사하였다. 본 연구에서는 철강 부산물인 압연슬러지 외에 석회석 미분물, 인산부산 석고를 혼합하여 칼슘알루미네이트상을 합성하였다. 합성 결과 소성온도 1250$^{\circ}C$에서부터 CSA가 합성되었고, 이와 함께 칼슘실리케이트 (2CaO$\cdot$$SiO_2$)와 칼슘알루미노페라이트(4CaO$\cdot$$Al_2O_3$$\cdot$$Fe_2O_3$)도 함께 합성되었다. CSA 합성에 미치는 중금속 영향을 관찰한 결과 원료의 중금속이 CSA 합성 온도를 낮추는 효과가 있는 것으로 나타났다. CSA를 이용한 철강산업 폐기물의 중금속 고용 처리 연구에서도 본 실험에서 합성된 CSA가 폐기물의 중금속 고화 처리에 효과가 있는 것으로 나타났다.

  • PDF

Electrical Properties of Coatings of Polyaniline (Polyaniline을 이용한 코팅막의 전기적 특성)

  • 김언령;김종은;서광석
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.11a
    • /
    • pp.310-313
    • /
    • 2000
  • Polyaniline Emeraldine Base (PANI EB) polymerized by chemical oxidative polymerization was doped with Camphorsulfonic Acid(CSA). Polyaniline-Camphorsulfonic Acid Emeraldine Salt(PANI-CSA ES) solutions were solved in organic solvents and sonificated at the room temperature for different solvents in PANI-CSA ES solution and sonification time. PANI-CSA ES solutions was coated on PET films using bar coater. 1-Step oxidatively-polymerized Polyaniline-Camphorsulfonic Acid Emeraldine Salt(PANI-CSA ES) was solved in m-cresol:chloroform 1:1 co-solvents and their solution was bar-coated on PET film. The surface resistivities of these coated films were measured, The surface resistivity of PANI-CSA ES solution in m-cresol:chloroform 1:1 co-solvent system was 5${\times}$10$^2$$\Omega$/$\square$.

  • PDF

Topology and size optimization of truss structures using an improved crow search algorithm

  • Mashayekhi, Mostafa;Yousefi, Roghayeh
    • Structural Engineering and Mechanics
    • /
    • v.77 no.6
    • /
    • pp.779-795
    • /
    • 2021
  • In the recent decades, various optimization algorithms have been considered for the optimization of structures. In this research, a new enhanced algorithm is used for the size and topology optimization of truss structures. This algorithm, which is obtained from the combination of Crow Search Algorithm (CSA) and the Cellular Automata (CA) method, is called CA-CSA method. In the first iteration of the CA-CSA method, some of the best designs of the crow's memory are first selected and then located in the cells of CA. Then, a random cell is selected from CA, and the best design is chosen from the selected cell and its neighborhood; it is considered as a "local superior design" (LSD). In the optimization process, the LSD design is used to modify the CSA method. Numerical examples show that the CA-CSA method is more effective than CSA in the size and topology optimization of the truss structures.

Review on Carbonation Curing and Thermal Stability of Calcium Sulfoaluminate Cement (칼슘설포알루미네이트 시멘트의 탄산화 양생과 열 안정성에 관한 검토)

  • Wu, Xuanru;Kunal Krishna, Das;Jang, Jeong Gook
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2023.05a
    • /
    • pp.53-54
    • /
    • 2023
  • In recent decades, climate change has become an issue of global importance. The calcium sulfoaluminate (CSA) cement emits lower CO2 than the Portland cements while manufacturing. However, ettringite, which is a main hydration product of CSA cement, starts dehydrating at a temperature above 100℃, hence it may limit the CSA cement for high temperature application. Recently, an early carbonation curing of cement-based material has been extensively studied in terms of carbon neutralization. The carbonation curing of CSA cement has a potential to transform the AFt and AFm phases into calcium carbonate, and the transformation of unstable hydrates to stable hydrates can increase the resistance to elevated temperature. This review study summarizes and discusses the carbonation curing effect of CSA cement and the thermal stability of CSA cement exposed to elevated temperatures.

  • PDF

Study on Activity, Type and Establishment of Community Supported Agriculture in USA and Japan (미국과 일본의 CSA운동의 등장, 유형 및 활동사례)

  • 정진영;손상목;김영호
    • Korean Journal of Organic Agriculture
    • /
    • v.9 no.1
    • /
    • pp.1-16
    • /
    • 2001
  • With increasing global concern that intensively synthetic-chemical based farming systems accelerated the decline in environmental quality, the sustainability of modem agriculture became the subject of great concern. It is well known that the movement of Community Supported Agriculture(CSA) has been contributed significantly to the development of organic agriculture in USA and Japan. It was supposed that CSA could be one of the best way to promote the movement of organic agriculture since there is little reliability on the organically grown food by consumer. In this paper it was focussed to study the movement of CSA in USA and Europe in order to provide an idea for establishment and movement of CSA in Korea to support the organic agriculture. In a CSA system, the farmer grows food for a group of shareholders who pledge to buy a portion of the farm's crop that season. This arrangement gives growers up-front cash to finance their operation and higher prices for produce, since the middleman has been eliminated. For most shareholder for CSA saving money is a secondary consideration, but fresh safe products and environmentally sound farming system. People become shareholder of CSA since they expect an organic farming which can ; \circled1protect the environment, minimize pollution, promote health, \circled2replenish and maintain long-term soil fertility by providing optimal conditions for soil biological activity, \circled3maintain diversity within the farming system and its surroundings and protect plant and wildlife habit, \circled4recycle materials and resources to the greatest extent possible within the farm and its surrounding community, \circled5maintain the integrity of organic food and processed products through each step of the process from planting to consumption, \circled6develop and adopt new technologies with consideration for their long range social and ecological impact. In all CSAs, the farmer develops a crop plan and a budget, which details costs for a growing season, including fair wages for the farmers. Experienced Information on increasing shareholder retention, the future of CSA, and getting started such as ideas for ongoing marketing, printed materials that set realistic expectations, working members, production, pick-up and delivery, setting prices, and receiving feedback were also briefly introduced.

  • PDF

Effect of Carthami Semen Aquacupunture(CSA) on Mercury-Induced Alterations in Tubular Transport Function in Rabbits (홍화자약침액(紅花子藥鍼液)이 수은(水銀)에 의한 가토(家兎)의 신세뇨관(腎細尿管) 물질이동(物質移動) 변화(變化)에 미치는 영향(影響))

  • Choi, Young-gyu;Youn, Hyoun-min;Song, Choon-ho;Jang, Kyung-jeon;Abn, Chang-beohm
    • Journal of Acupuncture Research
    • /
    • v.19 no.5
    • /
    • pp.199-208
    • /
    • 2002
  • Objective : This study was undertaken to determine if Carthami Semen Aquacupunc- ture(CSA) exerts protective effect against alterations in membrane transport function rabbits with mercury chloride(HG)-induced acute renal failure. Methods : The administration of Hg at a subcutaneous single dose of 10 mg/kg caused a reduction in GFR and an increase in fractional Na excretion, indicating generation of acute renal failure. When CSA were given for 7 days prior to Hg administration, such changes were significantly attenuated. The fractional excretion of glucose and phosphate was increased in rabbits treated with Hg alone. Results : The increase in rabbits treated with Hg following CSA are significantly lower than that in animals treated with Hg alone. Uptakes of glucose and phosphate in purified isolated brush-border membrane and Na-K-ATPase activity in microsomal fraction were inhibited in rabbits treated with Hg alone. Such changes were prevented by CSA. Uptakes of organic ions, PAH and TEA, in renal cortical slices were inhibited by the administration of Hg, which was prevented by CSA. Exposure of renal cortical slices to Hg in vitro caused an increased LDH release and lipid peroxidation, which was significantly prevented by CSA extract. Conclusions : These results indicate that the administration of Hg causes impairment in reabsorption of solutes in the proximal tubule via the generation of reactive oxygen species. CSA provides the protection against the impairment in proximal reabsorption, and its effect may be resulted from its antioxidant effect.

  • PDF