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A Parametric Analysis of Performance of Gas Turbine Combined, Split Cylinder, Constant Volume, Pressure, Temperature, Mixed Cycle Engine (가스터빈 결합, 분리실린더, 등적.등압.등온 혼합사이클 엔진성능의 변수 분석)

  • Kim Dong-Ho;Bae Jong-Uk
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.7
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    • pp.1082-1091
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    • 2004
  • Analyzed Parametrically was an internal combustion engine combined with gas turbine the cycle of which is splitted into compression side cylinder and expansion side one, and heat adding of which is during constant volume pressure, temperature process. The advantages of each measures were analyzed by means of thermal cycle diagram. The thermal efficiency of partial load cutting off firstly isothermal heat adding and secondly isobaric heat adding also was analyzed The authors suggested some potentials about the performance as for thermal efficiency, mean effective pressure and reducing emissions and noise supposed were the operating parameter of the engine set to some values and were some problems solved.

Mechanical properties of porcelain fused gold alloy containing indium, tin and copper (인듐, 주석, 동 첨가에 따른 도재소부용 금합금의 기계적 특성 변화)

  • Nam, Sang-Yong;Kwak, Dong-Ju;Lee, Deok-Su
    • Journal of Technologic Dentistry
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    • v.24 no.1
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    • pp.65-71
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    • 2002
  • This study was performed to observe the microhardness change of the surface and the bonding strength between the porcelain and alloy specimens in order to investigate the effects of appended indium, tin and copper on interfacial properties of Au-Pd-Ag alloys. The hardness of castings was measured with a micro-Vicker's hardness tester. The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with a mechanical testing system(MTS 858.20). The microhardness of Au-Pd-Ag alloy was increased by adding indium and tin, but not increased by adding copper. The shear bonding strength of Au-Pd-Ag-Sn alloy and Au-Pd-Ag-Cu alloy showed 87MPa, 57MPa. The higher concentration of adding elements showed the higher shear bonding strength.

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Experimental Study on Properties of Concrete Incorporating Inoragnic Antifouling Agent (무기계 방오(防汚)제가 혼입된 콘크리트 특성에 관한 실험적 연구)

  • Kim, Yeon-Bong;Nam, Jae-Hyun
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.2 s.16
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    • pp.97-105
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    • 2005
  • Concrete structures in the marine environment often deteriorate in the early stage of their service life because of contact with various aggressive conditions. In recent years, the researches on the concrete in the marine environment have been carried out to increase their service life. In this experimental study, the concrete specimens were prepared with various adding contents of inorganic antifouling agent$(0\~3.0wt\%)$ composed of some fluosilicate solution. For evaluation of the properties of concretes containing inorganic antifouling agent, various tests such as setting time, slump loss, compressive strength, water absorption rate, fleering and thawing resistance and SEM of concrete, were conducted. As the results, physical and chemical properties of concretes were improved with an adding of inorganic antifouling agent. From the results of various tests, the optimal adding contents of antifouling agent was $1.0wt\%$.

Electrochemical Properties of Conducting Polymer for Supercapacitor (Supercapacitor용 도전성 고분자의 전기화학적 특성)

  • 강광우;김종욱;김명산;구할본;김형곤
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.4
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    • pp.323-327
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    • 2001
  • The purpose of this study is to research and develop conducting polymer(CP) composite electrode for supercapacitor. The radius of semicircle of CP composite cell with polyaniline(PAn) composite electrode adding 30wt% acetylene black was small. The total resistance of supercapacitor cell mainly depended on internal resistance of he electrode. The discharge capacitance of supercapacitor cell with PAn composite electrode adding 30wt% acetylene black in 1st and 50th cycles was 27F/g and 31F/g at current density of 1mA/$\textrm{cm}^2$, respectively. Supercapacitor cell with PAn composite electrode adding 30wt% acetylene black showed a good cycliability. Supercapacitor cell of CP composite electrode with 1M LiClO$_4$/PC brings out god capacitor performance below 4V.

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Water and oxygen permeation through transparent ethylene vinyl alcohol/(graphene oxide) membranes

  • Kim, Hye Min;Lee, Heon Sang
    • Carbon letters
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    • v.15 no.1
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    • pp.50-56
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    • 2014
  • We prepared ethylene vinyl alcohol (EVOH)/graphene oxide (GO) membranes by solution casting method. X-ray diffraction analysis showed that GOs were fully exfoliated in the EVOH/GO membrane. The glass transition temperatures of EVOH were increased by adding GOs into EVOH. The melting temperatures of EVOH/GO composites were decreased by adding GOs into EVOH, indicating that GOs may inhibit the crystallization of EVOH during non-isothermal crystallization. However, the equilibrium melting temperatures of EVOH were not changed by adding GOs into EVOH. The oxygen permeability of the EVOH/GO (0.3 wt%) film was reduced to 63% of that of pure EVOH film, with 84% light transmittance at 550 nm. The EVOH/GO membranes exhibited 100 times better (water vapor)/(oxygen) selectivity performance than pure EVOH membrane.

The Quality Characteristics of Rice-Corn Cakes (옥수수 가루를 첨가한 Rice-Corn Cakes의 특성에 관한 연구)

  • 김영인
    • Korean journal of food and cookery science
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    • v.17 no.5
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    • pp.426-430
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    • 2001
  • This experiment was carried out to investigate the effects of adding corn flour on the quality of rice cakes. Rice-corn cakes were prepared by adding corn flour at 25%, 50% and 75%, and the quality characteristics were measured. In the expansion ratio, springiness and cohesiveness of rice-corn cakes, the 25% group(C-25) was the highest and the 75% group(C-75) was the lowest. The higher the ratio of adding corn flour was, the lower the expansion ratio, springiness and cohesiveness were. In the hardness and chewiness of rice-corn cakes, the 75 % group(C-75) was the highest and the 25% group(C-25) was the lowest. But in the taste, texture and overall acceptance of rice-corn cakes, the 50% group(C-50) was the best.

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Non-Value Adding Activities in South African Construction: A Research Agenda

  • Emuze, Fidelis;Smallwood, John
    • Journal of Construction Engineering and Project Management
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    • v.1 no.3
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    • pp.38-44
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    • 2011
  • The central issue in this particular research is the seemingly inadequate achievement of optimum performance in the construction process, either with respect to value for money for the client and the entire construction supply chain or value in terms of the utility derived from built assets in spite of efforts by government and governmental bodies such as the Construction Industry Development Board (cidb) to increase industry performance. Therefore, based upon an extensive review of related literature, the paper reports on effects and causes of non-value adding activities in the construction industry in general, and South African construction in particular. The research findings indicate that activities that can be referred to as non-value activities are not only prevalent, but they can also be held responsible for performance related issues in terms of cost, time, quality and health and safety (H&S) in construction; and the exploration of pluralism in the research methodology may result in a robust model based upon the system dynamics approach.

Effect of Additives and Control of Sintering Atomsphere on Magnetic Properties of Mn-Zn Ferrite (첨가제 및 분위기 제어가 Mn-Zn Ferrite의 자기적 특성에 미치는 영향)

  • 이웅용;이대희;김창현;이병교
    • Journal of the Korean Ceramic Society
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    • v.35 no.8
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    • pp.836-842
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    • 1998
  • In this experiment well-know additives for Mn-Zn ferrites CaO and {{{{ { SiO}_{2 } }} were added at various content and their effects on microstructures and magnetic properties with sintering atmosphere were examined. By adding up to 0.04wt% {{{{ { SiO}_{2 } }} and and 0.06wt% CaO the sintered density was increased and then decreased gra-dually. Higher sintered density and initial permeability were observed by adding both CaO and {{{{ { SiO}_{2 } }} than by adding CaO or {{{{ { SiO}_{2 } }} alone. Without any additives initial permeability and tan$\delta$/${\mu}$ decreased at 1000kHz as oxidation degree(${\gamma}$) increased.

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Effect of Organic Admixture(Calcium Lignosulfonate) (I) on the Early Hydration Process of Protland Cement (시멘트 초기 수화과정에 대한 유기혼화제의 영향(I))

  • 문정연;최상홀
    • Journal of the Korean Ceramic Society
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    • v.21 no.2
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    • pp.143-148
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    • 1984
  • In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

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A Study on Risk Assessment of Methyl Ethyl Ketone Peroxide (메틸에틸케톤 퍼옥사이드의 위험성평가에 관한 연구)

  • Mok, Yun-Soo
    • Journal of the Korean Society of Safety
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    • v.20 no.4 s.72
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    • pp.34-39
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    • 2005
  • To evaluate characteristics of explosion hazard of Methyl Ethyl Ketone Peroxide, MCPVT was used for this study. In result maximum explosion pressure and maximum explosion pressure rising velocity of MEK-PO were $12.1kgf/cm^2\;and\;106.81kgf/cm^2/s$. As a result or adding metal powder to estimate hazard of explosion, the maximum explosion pressure and maximum explosion pressure rising velocity according to adding Fe powder in MEK-PO increased. In opposite, those decreased resulting in adding Ca powder in MEK-PO.