폐주불사를 혼입한 콘크리트의 내구성에 관한 연구

김태경,박정호,이정호,이주형,박제선,김연경,윤경구 강원대학교 석재복합신소재제품연구센터 1998 석재연 논문집 Vol.3 No.-

콘크리트 구조물은 자연적인 혹은 인위적인 온도의 상승, 강하로 인하여 동결-융해 작용을 받게 되어 구조물의 성능저하를 야기시킨다. 현대에 들어서면서 콘크리트의 내구특성을 파악하기 위한 연구적 요구가 증가되고 있다. 따라서 폐주물사 콘크리트를 실제 구조물에 적용하기 위해서는 내구특성에 대한 연구가 반드시 이루어져야 한다. 폐주물사를 혼입한 콘크리트의 내구특성을 파악하기 위한 동결-융해 실험은 폐주물사의 잔골재 치환율, 물-시멘트비, AE제 사용 여부를 주요 변수로 하여 실시하였다. 원형공시체를 제작하여, 동결-융해 시험기에 넣어 -18∼4℃로 급속 동결-융해를 진행시키면서 매 23싸이클마다 동탄성계수를 측정하였다. 실험결과 AE제를 첨가했을 때 물-시멘트비가 적을수록, 폐주물사의 치환율이 클수록 전반적으로 강도가 증가하는 것으로 나타났으며, 물-시멘트비가 증가함에 따라, AE제를 사용한 콘크리트가 동결-융해 저항성이 증가하는 것으로 나타났다. 특히 폐주물사 치환율이 50%일 때가 동결-융해 저항성이 가장 좋은 것으로 나타났으며 그 다음으로 25, 0% 순으로 저항성이 좋은 것으로 나타났다. 따라서 폐주물사 콘크리트가 내구성이 우수한 것으로 나타나 폐주물사를 콘크리트에 재활용 할 수 있는 것으로 나타났다. Concrete structures has been deteriorated by the freezing and thawing due to temperature gap. This study was conducted to evaluate durability of concrete which are increasingly demanded recently. Therefore the research of durability must be executed for application of waste foundry sand concrete real structures. Concrete durability properties incorporating waste foundry sand was performed with the variable of W/C ratio, Sand/Waste foundry sand ratio and Air entrainment-Non air entrainment. Cylinder specimens were made and subjected to freezing and thawing cycle at -18℃ and 4℃. Dynamic modulus of elasticity were evaluated as F/T cycle increase. The results show that strength of concrete is increased the W/C ratio decrease, the Sand/Waste foundry sand ratio increase when the concrete contains AE agent and decreasing W/C ratio and AE concrete makes improved resistance of freezing and thawing improved. Especially, resistance of freezing and thawing is improved by Fine aggregate/Waste foundry sand ratio which is 50%, 25%, 0% in a row. Therefore it is turn out the waste foundry sand could be applied to concrete from the experiment.

ERP시스템에서 생산시스템 설계(A사 사례연구 중심으로)

윤영도,양광모,강경식 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

As business operations are globalized, the management information system which have been developed to support individual tasks in many companies are focused on the ineffectiveness. That in because the entire business transactions including production, accounting, personnel management, and logistics need to be integrated with a global perspective. To meet these requirements, many enterprises are planning or adopting the ERP package which has been recently assailable with the help of advanced information technologies. The target company of this study goes ahead with plan to adopt ERP systems. Hereupon, I want to present the issues which should be considered in the process of ERP system implementation. This study focuses on the manufacturing system, but it also discusses important issues on the selected business area. This study covers the material benefits and functionalities of ERP package as well as the importance of studying and understanding on business process, organization change management, and information technology. And this case study swart with a long-term plan and consider its own unique characteristics and environmental factors. But it is regrettable that I can not make a comparative analysis with other systems because the ERP system is still on the introductory stage for the company studies and the benefits have net been realized yet. Another limitation of this research is its narrow scope of study in which only the raw material inventory system for a single company is covered. In the future, however, ERP system would be adopted by many corporations, which would help us to launch a comparative study on the results of ERP system implementation as a future direction of research.

엔로플록사신 액제의 닭 호흡기 및 소화기 감염증에 대한 예방 및 치료효과

윤효인,박병권,조준형,정상희,박경환,장범수,김종춘,황윤환,임종환,이내경,박승춘 충남대학교 수의과대학 동물의과학연구소 2000 動物醫科學硏究誌 Vol.8 No.-

We evaluated the efficacy of the liquid form of enrofloxacin against poultry respiratory and digestive infections, the major problems in the poultry industry, from diverse diagnosis viewpoints. Results obtained through this study were as follows: 1. The liquid form of enrofloxacin showed good acceptability to poultry owing to no abhorrence to the drug by chickens, which indicated its suitability for mixing in drinking water. 2. The application of the enrofloxacin formulation improved the productivity of the chicken farm to a great extent by lowering the death toll of chicken raised in the farm. 3. The use of the drug shortened the days to the market, and increased the body weight at the time of marketing. 4. Preventive and therapeutic effects of the liquid enrofloxacin were observed higher than ampicillin, a major antibiotic used in poultry farming. From above results, the liquid form of enrofloxacin would find its use for the prevention and treatment of digestive and respiratory infections, let alone the growth promotion and feed efficiency, especially in the chicken farming practice.

초속경 LMC의 시험시공을 위한 시방배합 및 현장배합 연구

윤경구,김성환,정원경,최성욱 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

본 논문은 콘크리트 배합시 발생하는 과도한 기포 발생 문제점을 해결하기 위하여 최적의 소포제 종류 및 혼입률 범위를 산정하여 초속경 라텍스 개질 콘크리트 성능을 개선하는 것이다. 초속경 라텍스 개질 모르타르 실험은 4종류의 소포제 A, B, C, D와 혼입률 0, 1, 2, 3%을 주요 변수로 하여 실험을 수행하였으며, 초속경 라텍스 개질 모르타르 및 콘크리트의 특성을 분석하기 위하여 공기량 시험, 압축강도 및 휨강도 시험을 수행하였으며, 투수특성을 분석하기 위해서 염화이온 투과시험을 수행하였다. 초속경 라텍스 개질 모르타르의 공기량시험 결과 소포제 종류에 상관없이 소포제 혼입률 1%이상 첨가시 공기량은 50%이상 감소하였다. 또한, 소포제 첨가에 의한 기포발생량 감소에 의해서 압축강도의 증진을 이루었다. 초속경 라텍스 개질 콘크리트 실험은 모르타르 실험에서 우수한 특성을 나타낸 A, C 소포제로 선정하여 실험을 수행하였다. 초속경 라텍스 개질 콘크리트의 강도 특성에서는 A 소포제 혼입률 1%에서 압축강도 235 kgf/㎠, 휨강도는 조기 교통개방에 요구되는 휨강도 기준 45kgf/㎠를 초과하는 49kgf/㎠를 나타내었다. 초속경 라텍스 개질 콘크리트의 투수성을 분석하기 위한 염화이온투과시험에서 A 소포제는 각각 혼입률 1%, 2%에서 가장 우수한 투수저항성을 나타내어 재령 28일에서는 통과전하량이 100쿨롱 이하를 나타내어 불투수성을 나타내었다. The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as the basic for RSLMC with the main experimental variables such as antifiamer types (A, B, C, D), antifoamer contents (0, 1, 2, 3%), and latex contents (15%). A series of RSLMC experiments, also, were carried out with the similar main experimental variables but with the selected antifoamer types (A, C). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMM and RSLMC. Chloride ion permeability test was carried out to estimate water permeability resistance. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. Two kinds and the optimized quantities of antifoam agent were selected for using in RSLMC. The results of RELMC were obtained at a latex content of 15% and an antifoam agent quantity of 1% with antifoamer A type. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235 kgf/㎠ and 49kgf/㎠, respectively, which exceeded the flexural strength criterion of 45 kgf/㎠ in order to open the RSLMC placed to traffic. The rapid chloride permeability test was used to evaluate the permeability of RSLMC. The optimited quantity of antifoamer A and C type were 1% and 2% for the permeability test, respectively. The chloride permeability using A and C antifoamer at 28 days were below 100 coulombs, which was the permeability rating of negligible according to ASTM.

IDEF0를 이용한 중소제조업 생산시스템 업무프로세스 모델링

윤경수,전태보 강원대학교 정보통신연구소 2001 정보통신논문지 Vol.5 No.-

A business process model of a small manufacturing industry applying IDEF methodology has been presented in this study. Dynamically changing and competitive market environment specifically calls industries to be agile and adaptive. A proposed direction for manufacturing industries is to synthesize the internal business processes which have frequently been functionally separated. IDEF is a useful methodology to satisfy this need and the current production system, especially business, material handling, quality, and production control functions of the considered company have rigorously been analyzed and modeled. The results obtained in this study may serve a good reference to many small industries seeking for systematic integration of the system.

CRM 구축에 대한 중점구축방안에 관한 연구

윤지태,양광모,강경식 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

With the help of the Internet, communication with customers and the frequency and speed of the problem solving has improved greatly. At this point mayor enterprises are paying much attention to CRM and their related markets are expanding rapidly I'll give a brief introduction to the CRM system and go into the problems that should be considered and which phase to emphasize when building this system.

블록들의 유사성을 고려한 Adaptive Block-Wise RPLS

윤경우,이영학,한종훈 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.5

부분 최소 자승법 (partial least squares, PLS)은 복잡한 공분산 구조를 가진 상관성이 큰 변수들이 포함된 공정을 모델링 하는데 효과적으로 사용되어 왔다. 하지만 공정 변화에 적응하는 온라인 모델을 만들기 위해 부분 최소 자승법을 이용하는 것은 많은 제약이 따른다. 그래서 많이 이용되고 있는 방법이 recursive PLS(RPLS)이다. RPLS는 새로운 데이터 샘플이 들어오면 모델을 갱신 한다. 하지만 데이터의 상당한 양이 모이거나 공정의 큰 변화가 있을 때까지 모델을 갱신하지 않을 수도 있다. 따라서 이 논문에서는 공정 변화에 잘 적응하고 모델 갱신을 블록 단위로 하는 block-wise RPLS의 온라인 적응 방법인 moving window 방법을 이용하였다. Block-wise RPLS는 희귀 모델을 만들고 검증하는데 필요한 계산 부하를 감소시키는 효과가 있다 본 연구에서는 모델을 구성하는 윈도우내에 있는 블록들 사이의 상관관계를 나타내는 지표를 정의한 다음, 그 지표를 통해 forgetting factor를 정하는 방법을 제시하였다. 이 방법은 공정에 대한 일반적인 지식이 필요하지 않고 단지 데이터 블록의 상관관계만으로 적응 모델의 예측력을 높일 수 있는 방법이다. 따라서 다른 방법들이 나타내지 못한 상관성 정보를 포함시켰다. 이 방법을 기반으로 정유 공장의 가열로의 NO_(x)(nitrogen oxides) 배출 농도를 예측하는 모델을 forgetting factor를 이용해 구성했고, 이 forgetting factor에 의해 예측력이 최소 에러 값의 95%이상 근접함을 확인하였다. Partial least squares (PLS) regression has been effectively used as one of the data-driven empirical modeling to deal with a large number of variables in the complicated covariance structure. But Partial least squarer (PLS) regression has limitations in the online model update. Therefore, recursive PLS has ken used for the online adaptation of the model. The RPLS algorithm is implemented as soon as some new samples are available. It may be desirable not to update the model until significant amount of data are collected and the process has gone through significant changes. In this paper. we used the block-wise recursive partial least squares (RPLS) algorithms with a moving window for the adaptation of the model according to the process shins. The block-wise RPLS algorithm has been used to reduce computational load in PLS regression and its cross-validation. In this work we defined the index to represent correlation between blocks and proposed how to determine the forgetting factors through it. This proposed method is to improve the prediction power of the adaptive modeling considering correlation between blocks without general process knowledge. Therefore, this proposed method included correlation information that different methods did not express. The method was tested to process heaters in the oil refining wmpany. We costructed the prediction model of the effluent NO, composition with forgetting factors and showed that the prediction power approximated more than 95% of the minimum error.

엔로플록사신 액제의 닭유래 병원세균에 대한 시험관내 항균효과 시험

윤효인,박병권,조준형,정상희,박경환,장범수,김종춘,황윤환,임종환,이내경,박승춘 충남대학교 수의과대학 동물의과학연구소 2000 動物醫科學硏究誌 Vol.8 No.-

In this study the antimicrobial spectrum and sensitivity of a liquid formulation of enrofloxacin against the major six pathogenic bacteria isolated from the diseased poultry in Korea were evaluated in comparison with ciprfloxacin (CFX), gentamicin (GM) and penicillin (PC). A liquid form of enrofloxacin, a test material and ciprofloxacin showed at least 83% antibacterial activity against all of six test pathogenic microorganisms at the fixed concentration of 10 ㎍/㎖. Gentamicin and penicillin revealed much lower antibacterial activity at the same condition. We evaluated the liquid form of enrofloxacin as having widespread antibacterial spectrum against poultry infections. The liquid form of enrofloxacin showed potent antibacterial activity, with the MIC range being 0.12∼2 ㎍/㎖ against Gram positives, 0.06∼2 ㎍/㎖ against Gram negatives and 0.5∼2 ㎍/㎖ against Mycoplasma spp. These values were equivalent to or somewhat higher than those of ciprofloxacin, but much lower than those of gentamicn and penicillin. This new liquid form of enrofloxacin would find its way in application of mixing with drinking water for the prevention and treatment of diverse infections in chickens.

라텍스 개질 콘크리트의 건조수축특성

윤경구,홍창우,이주형 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. Therefore, the purpose of this dissertation was to study the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a same controlled environment of 60% of relative humidity and 20℃ of temperature. Test results revealed that the drying shrinkage of latex modified concrete(LMC), rapid-setting cement latex modified concrete(RSLMC) was considerably lower than that of ordinary portland cement concrete(OPC), rapid-setting cement concrete(RSC), respectively. This may be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic and colloidal properties of the latexes, resulting in reduced water evaporation.

라텍스 개질 콘크리트의 강도발현 및 내구특성

윤경구,홍창우,이주형,이종명 강원대학교 석재복합신소재제품연구센터 2001 석재연 논문집 Vol.6 No.-

본 연구는 라텍스 혼입률이 5%, 10%, 15%, 20%로 변화할 때 라텍스 개질 콘크리트의 내구 특성을 평가하는데 있다. 라텍스를 콘크리트에 혼입한 라텍스 개질 콘크리트는 보통 콘크리트의 색상과 성형성, 작업성를 갖으며, 약 20%~35%의 단위수향이 감소된다. 그리고 양생후, 콘크리트는 시멘트수화물과 라텍스 입자의 필름막에 의해 연결된 골재로 구성된다. 일반적으로 라텍스 양이 증가하면 콘크리트의 휨강도는 증가하는데, 이것은 라텍스가 시멘트 수화물과 골재사이의 점착력을 증가시키기 때문으로 판단된다. 라텍스 개질 콘크리트와 보통콘크리트와의 상대투수성을 측정하기 위하여 염소이온투과시험법을 사용하였다. 그 결과 라텍스 개질 콘크리트의 투수성은 보통콘크리트의 투수성보다 매우 낮음을 알 수 있었다. 이것은 라텍스가 미세공극을 충진하고 라텍스 입자의 필름막에 의해 골재와 시멘트수화물이 연결 때문이다. 또한 라텍스가 공극주위로 필름막을 형성하기 때문에 공기량이 투수성에 영향을 미치지 못한다는 것을 알 수 있었다. 보통콘크리트에서는 동결융해저항성을 증가시키기 위해 공기연행제를 필요로 하지만, 라텍스 개질 콘크리트에서는 적절한 양생이 이루어지면 추가적인 공기연행제는 요구되지 않는다. 또한 라텍스 혼입률이 증가함에 따라 추가적인 동결융해저항성의 증가는 나타나지 않았다. This study focused on the investigation of strength development and durability of latex modified concrete(LMC) as the latex content variated such as 5%, 10%, 15%, and 20%. When latex was added to concrete, the workability of LMC was quietly increased, compared to that of conventional concrete. This resulted in the decrease of the required water as 20% to 35% in order to obtain a same slump. In general, increasing the amount of latex decreased compressive strength a little but increased flexural strength quite a lot. This might be due to interconnection by a film of latex particles between hydrated cement and aggregates. This, also, might attribute to bonding between the hydrated cement and aggregates. The rapid chloride permeability test was used to evaluate the relative permeability of latex-modified concretes and conventional concretes. The results showed that the permeability of latex-modified concretes was considerably lower than that of conventional concretes tested, which might be due to the latex filled in voids and interconnections of hydrated cement and aggregates by a film of latex particles. Because of latex formed film surrounding the air void, air contents and voids does not effect to the permeability of latex modified concrete.