• 제목/요약/키워드: technical potential

검색결과 1,029건 처리시간 0.027초

공공공사 기술형 입찰에서의 낙찰가격에 미치는 요인 분석 (Analysis of Factors Affecting Successful Bid Price in Public Construction Technical Bidding)

  • 이정웅;이성욱
    • 아태비즈니스연구
    • /
    • 제13권1호
    • /
    • pp.213-230
    • /
    • 2022
  • Purpose - The purpose of this study is to find out any potential factors for explanatory variables when calculating the virtual successful bid rate in case of no collusion. Design/methodology/approach - An empirical analysis was conducted in this study with a regression analysis that included 725 bid samples under the public construction technical type bidding. Findings - The result of the basic analysis showed that there are several factors affecting the successful bid rate. First, collusion variable; second, government variable; third, successful bidder design score variable and the number of bidder variable among bidding features; fourth, turnkey variable based on the alternative method; fifth, civil works variable and plant works variable based on building work; sixth, asset variable and the fourth-quarter performance difference variable. However, the technical proposal method variable among bidding features was found to be statistically insignificant in column(4). Research implications or Originality - The significance of this research is that new variable such as the government variable and the fourth-quarter performance difference variable were added in the regression model, which showed statistically significant research results.

양이온 성분이 수산화철 형성에 미치는 영향 조사 (Studying the Effect of Cation to the Formation of Iron Oxyhydroxide)

  • 오세진;이재영;권순주;유장용;주웅용
    • 한국재료학회지
    • /
    • 제12권10호
    • /
    • pp.796-802
    • /
    • 2002
  • Effect of nine different cations to the formation of iron oxyhydroxide was studied using Mossbauer spectroscopy, XRD and BET. The Redox Potential and pH were measured for the determination of the internal reaction rate, as well. The phases of iron oxyhydroxide could not be the same with each other, due to the present of different cations in solution. Although the oxyhydroxide compound were composed of the same phases, the fraction of each phase was different from each other. The internal reaction rate was varied by the substitution of cation. It could be a cause of the different phase and particle size of oxyhydroxide compound.

LCA기법을 이용한 천연펄프의 환경 영향 평가 (Environmental Impact Evaluation of Virgin Pulp Using Life Cycle Assessment Methodology)

  • 김형진;조병묵;황용우;박광호
    • 펄프종이기술
    • /
    • 제36권1호
    • /
    • pp.49-60
    • /
    • 2004
  • Life Cycle Assessment for the pulp, which is mainly used as the raw material of fine paper, base paper for food packaging and paper cup, has been carried out in this study to consider environmental aspects by quantifying the environmental emission and to evaluate its environmental impact potential. The system boundary was selected from cradle to gate stage(raw material acquisition, transportation of raw material and product manufacturing) of the product. Environmental impact was divided into 8 categories considering Korean situation: abiotic resource depletion, global warming, ozone depletion, acidification, eutrophication, photochemical oxidant creation, ecotoxicity and human toxicity. In Life Cycle Impact Assessment(LCIA) methodology phase, Ecopoint, Eco-indicator 95 and Korean eco-indicator were used and the results carried out by each methodology were compared. The results from this study were also compared with those of foreign study to verify the reliability of the results. The results of the study could be utilized as the basic data for Environmental Management System(EMS), Design for Environment(DfE) and Type III eco-labeling in the paper and paper-related industry.

Application of Dynamic Probabilistic Safety Assessment Approach for Accident Sequence Precursor Analysis: Case Study for Steam Generator Tube Rupture

  • Lee, Hansul;Kim, Taewan;Heo, Gyunyoung
    • Nuclear Engineering and Technology
    • /
    • 제49권2호
    • /
    • pp.306-312
    • /
    • 2017
  • The purpose of this research is to introduce the technical standard of accident sequence precursor (ASP) analysis, and to propose a case study using the dynamic-probabilistic safety assessment (D-PSA) approach. The D-PSA approach can aid in the determination of high-risk/low-frequency accident scenarios from all potential scenarios. It can also be used to investigate the dynamic interaction between the physical state and the actions of the operator in an accident situation for risk quantification. This approach lends significant potential for safety analysis. Furthermore, the D-PSA approach provides a more realistic risk assessment by minimizing assumptions used in the conventional PSA model so-called the static-PSA model, which are relatively static in comparison. We performed risk quantification of a steam generator tube rupture (SGTR) accident using the dynamic event tree (DET) methodology, which is the most widely used methodology in D-PSA. The risk quantification results of D-PSA and S-PSA are compared and evaluated. Suggestions and recommendations for using D-PSA are described in order to provide a technical perspective.

펄프 종류와 지료 내 미세분 함량이 고분자전해질 multilayering에 미치는 영향 (Effect of Pulp Type and Fines Content in a Stock on the Polyelectrolyte Multilayering onto Pulp Fiber)

  • 진성민;류재호;이성린;윤혜정
    • 펄프종이기술
    • /
    • 제40권3호
    • /
    • pp.15-22
    • /
    • 2008
  • Properties of pulp fibers can be modified by LbL multilayering technology. We evaluated the effect of stock composition on the polyelectrolyte multilayering performance of pulp fibers in this study. Stock composition was varied with pulp type and fines content. Three types of pulp-Hw-BKP, BCTMP and KOCC-were treated with polyelectrolytes of poly-DADMAC and PSS. Fines content of stock were controlled at 0, 10, 20, 30, and 40%. Zeta potential of pulp fibers and charge demand of filtrate were evaluated. The highest adsorption ratio was obtained for BCTMP because of its shortest fiber length and highest specific surface area. Higher fines content in the stock increased the adsorption ratio of polyelectrolyte onto pulp fiber and it required a higher amount of polyelectrolyte for charge neutralization. For the pulp stock with higher fines content, a higher level of polyelectrolyte and the increased layer number were required to modify and stabilize the electrochemical properties of pulp fibers.

셀룰로오스 나노피브릴 현탁액의 탈수성 평가 및 양이온성 고분자전해질 투입의 영향 (Evaluation of Dewatering of Cellulose Nanofibrils Suspension and Effect of Cationic Polyelectrolyte Addition on Dewatering)

  • 류재호;심규정;윤혜정
    • 펄프종이기술
    • /
    • 제46권6호
    • /
    • pp.78-86
    • /
    • 2014
  • Since cellulose nanofibrils (CNF) has large specific surface area and high water holding capacity, it is very difficult task to remove water from the CNF suspension. However, dewatering of CNF suspension is a prerequisite of following processes such as mat forming and drying for the application of CNF. In this study, we evaluated the drainage of cellulose fibers suspension under vacuum and pressure conditions depending on the number of grinding passes. Also, the effect of the addition of cationic polyelectrolyte on dewatering ability of CNF suspension was investigated. Regardless of dewatering condition, the total drained water amount as well as the drainage rate were decreased with an increase in the number of grinding passes. Pressure dewatering equipment enables us to prepare wet CNF mat with relatively higher grammage. The cationic polyelectrolytes improved the dewatering ability of CNF suspension by controlling the zeta potential of CNF. The fast drainage was obtained when CNF suspension had around neutral zeta potential.

CO2 sequestration and heavy metal stabilization by carbonation process in bottom ash samples from coal power plant

  • Ramakrishna., CH;Thriveni., T;Nam, Seong Young;kim, Chunsik;Ahn, Ji Whan
    • 에너지공학
    • /
    • 제26권4호
    • /
    • pp.74-83
    • /
    • 2017
  • Coal-fired power plants supply roughly 50 percent of the nation's electricity but produce a disproportionate share of electric utility-related air pollution. Coal combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash and fly ash residues. These disposal coal ash residues are however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation process has been shown to have a potential for improving the chemical stability and leaching behavior of bottom ash residues. The aim of this work was to quantify the volume of $CO_2$ that could be sequestrated with a view to reducing greenhouse gas emissions and stabilize the contaminated heavy metals from bottom ash samples. In this study, we used PC boiler bottom ash, Kanvera reactor (KR) slag and calcined waste lime for measuring chemical analysis and heavy metals leaching tests were performed and also the formation of calcite resulting from accelerated carbonation process was investigated by thermo gravimetric and differential thermal analysis (TG/DTA).

Influence of polled direction on the stress distribution in piezoelectric materials

  • Ilhan, Nihat;Koc, Nagihan
    • Structural Engineering and Mechanics
    • /
    • 제54권5호
    • /
    • pp.955-971
    • /
    • 2015
  • In this paper, the influence of the polled direction of piezoelectric materials on the stress distribution is studied under time-harmonic dynamical load (time-harmonic Lamb's problem). The system considered in this study consists of piezoelectric covering layer and piezoelectric half-plane, and the harmonic dynamical load acts on the free face of the covering layer. The investigations are carried out by utilizing the exact equations of motion and relations of the linear theory of electro-elasticity. The plane-strain state is considered. It is assumed that the perfect contact conditions between the covering layer and half-plane are satisfied. The boundary value problems under consideration are solved by employing Fourier exponential transformation techniques with respect to coordinates directed along the interface line. Numerical results on the influence of the polled direction of the piezoelectric materials such as PZT-5A, PZT-5H, PZT-4 and PZT-7A on the normal stresses, shear stresses and electric potential acting on the interface plane are presented and discussed. As a result of the analyses, it is established that the polled directions of the piezoelectric materials play an important role on the values of the studied stresses and electric potential.

Quantitative Characterization of Internal Fibrillation of Pulp Fiber

  • Won, Jong-Myoung;Lee, Jae-Hun
    • 펄프종이기술
    • /
    • 제39권1호
    • /
    • pp.1-7
    • /
    • 2007
  • Internal fibrillation of pulp fiber is an important factor affecting paper properties. Internal fibrillation of pulp fiber is usually introduced with several kinds of modifications of fiber by the mechanical treatment such as refining, high shear and/or high consistency mixing, etc. Unfortunately there are no standardized methods that can characterize the extent of internal fibrillation and its contribution on the paper properties. The purpose of this study is to try and find the potential methods that can characterize the internal fibrillation of pulp fiber quantitatively. Softwood bleached kraft pulp was treated with Hobart mixer to introduce the internal fibrillation without the significant fiber damage and external fibrillation. The extent of internal fibrillation was increased with the increase of mechanical treatment consistency. Several fiber properties were measured to find the potential means that could characterize and quantity the internal fibrillation. Laminated area could not be used as a means for quantifying the internal fibrillation because of the effect of swelling and the different internal fibrillation behavior at different mechanical treatment consistency. Micro and macro internal fibrillation models were proposed for describing the different behavior for the mechanical treatment at low and high consistencies of pulp. The Internal fibrillation showed good correlation with swelling of fiber wall. This trend was confirmed through the measurement of wall thickness and/or cross section area of fiber. Therefore the internal fibrillation possibly can be described as the indices indicating the change of wall thickness and/or cross section area.

전단 조건이 중질탄산칼슘의 무세척 고분자전해질 다층흡착 처리에 미치는 영향 (Effect of Shear Condition on Washless Polyelectrolytes Multilayering Treatment on GCC)

  • 이제곤;심규정;이학래;윤혜정
    • 펄프종이기술
    • /
    • 제46권5호
    • /
    • pp.51-60
    • /
    • 2014
  • To find a practical application approach of polyelectrolyte multilayering (PEM) on inorganic filler, we introduced PEM process without washing step and investigated the effect of shear condition on the washless PEM treatment of ground calcium carbonate (GCC). Washless multilayering on GCC was conducted under various shear conditions such as stirring, homogenization, and ultrasonication. Highly charged polyelectrolytes combination of polydiallyldimethylammonium chloride (PDADMAC) and poly sodium 4-styrene sulfonate (PSS) and low charged polyelectrolytes combination with cationic starch and anionic polyacrylamide (PAM) were compared. In the case of highly charged polyelectrolytes combination, shear conditions did not affect the zeta potential and the particle size of treated GCC. However, the modified GCC particles with low charged polyelectrolytes were more dispersed under higher shear condition while maintaining the zeta potential. In addition, GCC was successfully modified through laboratory inline washless polyelectrolyte multilayering system which consists of homogenizers and pumps.