The steel pipe manufacturing industry deals with facilities and materials. Especially thermal facilities are close to vapor cloud explosion (VCE) and may cause secondary damage to facilities because they deal with corrosive substances such as hydrofluoric acid, sulfuric acid and acid, fire, explosion, leakage etc. It is in danger. In this study, hazard identification method was conducted using HAZOP techniques and quantitative risk analysis was conducted using e-CA, a program that supports accident impact analysis. Equipment in the influence range of ERPG - 3 was determined to be a facility requiring replacement. It was decided that neutralization is necessary using slaked lime. Based on the cost of loss, We presented the proper replacement which is the timing of the dangerous facility. As a result, It was ideal to replace the facilities with 20 years of heat treatment facilities, one year of hydrofluoric acid storage tank, 20 years of sulfuric acid storage tank, and 5 years of hydrochloric acid storage tank.

This study suggests a model of production information system that can reduce manufacturing lead time and uniformize quality by using DNC S/W as a part of constructing production information management system in the industrial field of the existing marine engine block manufacturing companies. Under the effect of development of this system, the NC machine interface device can be installed in the control computer to obtain the quality information of the workpiece in real time so that the time to inspect the process quality and verify the product defect information can be reduced by more than 70%. In addition, the reliability of quality information has been improved and the external credibility has been improved. It took 30 minutes for operator to obtain, analyze and manage the quality information when the existing USB memory is used, but the communication between the NC controller computer and the NC controller in real time was completed to analyze the workpiece within 10 seconds.

With the recent development of manufacturing technology and the diversification of consumer needs, not only the process and quality control of production have become more complicated but also the kinds of information that manufacturing facilities provide the user about process have been diversified. Therefore the importance of big data analysis also has been raised. However, most small and medium enterprises (SMEs) lack the systematic infrastructure of big data management and analysis. In particular, due to the nature of domestic manufacturing companies that rely on foreign manufacturers for most of their manufacturing facilities, the need for their own data analysis and manufacturing support applications is increasing and research has been conducted in Korea. This study proposes integrated analysis platform for process and quality analysis, considering manufacturing big data database (DB) and data characteristics. The platform is implemented in two versions, Web and C/S, to enhance accessibility which perform template based quality analysis and real-time monitoring. The user can upload data from their local PC or DB and run analysis by combining single analysis module in template in a way they want since the platform is not optimized for a particular manufacturing process. Also Java and R are used as the development language for ease of system supplementation. It is expected that the platform will be available at a low price and evolve the ability of quality analysis in SMEs.

쌀 함량 100%인 쌀 쿠키를 제조하여 밀도, 퍼짐성, 색도, 경도, 지방산 함량을 측정하였다. 밀도는 밀쿠키와 쌀 쿠키에서 유의적인 차이가 나타나지 않으나, 쌀 쿠키에서 반죽의 밀도가 높은 경향을 나타냈다. 퍼짐성의 결과는 밀쿠키보다 쌀 쿠키에서 퍼짐성이 낮아지는 경향을 보였다. 쌀 쿠키의 색도는 명도를 나타내는 L값은 밀쿠키보다 쌀 쿠키에서 명도가 높게 나타났으며 적색도를 나타내는 a값은 밀쿠키보다 쌀 쿠키에서 낮은 값을 나타냈다. 황색도를 나타내는 b값은 밀쿠키와 쌀 쿠키에 차이가 나타나지 않았으며, 쌀 쿠키에서 경도가 낮아지는 경향을 보였다. 쌀 쿠키의 지방산 함량은 포화지방산은 myristic acid, palmitic acid, stearic acid로 나타났다. 밀쿠키에 비해 쌀 쿠키에서 포화지방산함량이 낮아지는 경향을 보였다. 단일불포화지방산은 주로 oleic acid로 구성된것으로 확인되었다. 다가불포화지방산의 조성은 linoleic acid로 구성된 것으로 확인되었으며, 밀쿠키보다는 쌀 쿠키에서 높게 나타났다. 필수지방산인 linoleic acid, linolenic acid, arachidonic acid의 경우, 밀로 제조한 것보다는 쌀 가루로 만든 쿠키에서 함량이 높게 나타났다.

The hydrogen reduction behavior of MoO3-CuO powder mixture for the synthesis of homogeneous Mo-20 wt% Cu composite powder is investigated. The reduction behavior of ball-milled powder mixture is analyzed by XRD and temperature programmed reduction method at various heating rates in Ar-10% H2 atmosphere. The XRD analysis of the heat-treated powder at 300oC shows Cu, MoO3, and Cu2MoO5 phases. In contrast, the powder mixture heated at 400oC is composed of Cu and MoO2 phases. The hydrogen reduction kinetic is evaluated by the amount of peak shift with heating rates. The activation energies for the reduction, estimated by the slope of the Kissinger plot, are measured as 112.2 kJ/mol and 65.2 kJ/mol, depending on the reduction steps from CuO to Cu and from MoO3 to MoO2, respectively. The measured activation energy for the reduction of MoO3 is explained by the effect of pre-reduced Cu particles. The powder mixture, hydrogen-reduced at 700oC, shows the dispersion of nano-sized Cu agglomerates on the surface of Mo powders.

Composites of P25 TiO2 and hexagonal WO3 nanorods are synthesized through ball-milling in order to study photocatalytic properties. Various composites of TiO2/WO3 are prepared by controlling the weight percentages (wt%) of WO3, in the range of 1–30 wt%, and milling time to investigate the effects of the composition ratio on the photocatalytic properties. Scanning electron microscopy, x-ray diffraction, and transmission electron microscopy are performed to characterize the structure, shape and size of the synthesized composites of TiO2/WO3. Methylene blue is used as a test dye to analyze the photocatalytic properties of the synthesized composite material. The photocatalytic activity shows that the decomposition efficiency of the dye due to the photocatalytic effect is the highest in the TiO2/ WO3 (3 wt%) composite, and the catalytic efficiency decreases sharply when the amount of WO3 is further increased. As the amount of WO3 added increases, dye-removal by adsorption occurs during centrifugation, instead of the decomposition of dyes by photocatalysts. Finally, TiO2/WO3 (3 wt%) composites are synthesized with various milling times. Experimental results show that the milling time has the best catalytic efficiency at 30 min, after which it gradually decreases. There is no significant change after 1 hour.

폴리에틸렌이민(분자량 800)에 다가이온을 갖는 정삼투용 새로운 유도용질을 합성하고 특성을 분석하였다. 폴리 에틸렌이민과 메틸 아크릴레이트의 중화반응으로 중간체를 합성하고, KOH로 가수분해하여 수용성의 카복실산 금속염 형태의 폴리에틸렌이민을 합성하였다. NMR, 점도, 삼투압을 측정하여 유도용질의 특성을 평가하였다. 그 염이 유도용질로서 사 용할 수 있는지의 여부를 정삼투 실험을 통하여 알아보았다. 유도용질로서 수투과도와 역염 투과도를 측정하여 NaCl과 비교 하였다. 정삼투와 나노여과의 혼성공정을 통하여 유도용질의 회수가능성을 보였다.

이소프로필알코올/물 혼합물은 가교된 폴리비닐알코올 복합막을 이용하여 투과특성평을 알아보았다. 검화도가 다 른 3종 PVA를 이용하여 고분자의 농도와 GA 농도에 따라서 투과특성을 확인하였다. 복합막은 PVA 용액을 PAN 지지체 위에 캐스팅한 후, 열가교를 통해 제조하였다. PVA 농도가 증가할수록 투과도는 감소하지만 선택도는 증가하는 것을 확인하였다. PVA-3이 7 wt% 농도로 코팅된 복합막에서 209 g/m2h의 투과도를 가지고, 100 이상의 선택도를 가지는 것을 확인하였다. 침지형 분리막을 제조하여 feed tank 온도와 feed 용액의 IPA 농도에 따라서 투과실험을 확인하였다. 또한 IPA 수용액에 농축실험을 지속적으로 한 결과, 60시간 후에 IPA의 농도가 99%까지 증가하는 것을 확인하였다.

본 연구에서는 활성탄소섬유를 이용하여 축전식 탈염공정에 적용할 탄소전극을 제조하였다. polyvinylidene fluoride (PVDF)를 바인더로 사용했으며 적절한 용매에 활성탄소섬유를 배합한 후 상용의 그라파이트 시트에 캐스팅하여 탄소전극을 제조하였다. 이 때 활성탄소섬유의 입자 크기를 달리하였고, 용매, 고분자 바인더 그리고 활성탄소섬유를 80 : 2 : 18, 80 : 5 : 15의 배합비율로 전극을 제조하였다. 그런 다음 염 제거 효율을 흡착전압과 시간, 탈착전압과 시간, NaCl 공급액의 농도와 유속 등에 운전조건에 대하여 염 제거 효율을 측정하였다. 대표적으로 활성탄소섬유의 입자크기가 32 μm 이하이며 80 : 2 : 18의 배합비율에서 1.2 V, 3분의 흡착조건, -0.1 V, 1분의 탈착조건, NaCl 100 mg/L, 15 mL/min의 공급액 조건에서 53.6%의 염 제거 효율을 보였다.

이전 연구에서 올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparicles (AgNPs)(전구체AgBF4)/pbenzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지 되는 것이 확인되었다. 하지만 전구체인 AgBF4의 가격이 고가이기 때문에, 본 연구에서는 가격 측면에서 경쟁력이 있는 AgNO3를 Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과 이미 존재하고 있는 NO3 -가 AgNPs를 감싸고 있기 때문에 분리 성능이 나오지 않는 것으로 관찰되었다. 이번 연구에서는 AgNO3를 Ag nanoparticles의 전구체로 사용하여도 높은 성능을 내기 위해 전자수용체 7,7,8,8-tetracyanoquinodimethane (TCNQ)를 사용하여 PEO, polyvinyl alcohol (PVA), polyether block amide-1657 (PEBAX-1657) 고분자 복합막을 제조한 결과, 고분자와 전자수용체의 영향과는 무관하게 분리 성능을 내지 못하는 것으로 분석되었으며, 이는 분리성능에 전구체의 음이온이 결정적 역할을 하는 것으로 분석되었다.

올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparticles (AgNPs)(전구체: AgBF4)/p-benzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지되는 것이 관찰 되었다. 분리막의 성능이 100시간까지 유지할 수 있었던 이유는 p-BQ의 첨가로 인해 Ag ion이 안정적으로 Ag nanoparticles 로 형성될 수 있었을 뿐더러 전자수용체인 p-BQ으로 인해 표면이 부분 양극성화 되어 올레핀 운반체로서 역할을 성공적으로 수행한 결과라 생각되었다. 본 연구에서는 Ag nanoparticles의 전구체로 사용된 AgBF4의 가격이 고가이기 때문에 가격 측면에서 유리한 AgNO3 Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과로서 AgNO3의 경우에는 앞선 AgBF4 과는 다르게 안정적으로 은 나노입자가 형성되지 못하고 이로 인하여 좋은 성능을 내지 못하는 것으로 분석되었다.

To improve life time of machine components, higher alloy grade materials are used by adding more metal alloy components and content. Also production processes are further complicated and subdivided such as the forging, preliminary heat treatment, quality heat treatment, rough machining and finished machining process. Those reasons become major cause of large stress in the materials, and the residual stress generated during the manufacturing process causes fatal defects, such as crack, surface tear, warping and deformation of the products. It is necessary to evaluate the residual stress on the entire processes, from forging process to final finished machining process. Also in order to avoid those problems caused by residual stresses, it is necessary to know in advance what process is important to be controlled and what parameters affect residual stress. By the hole drilling method, residual stress was measured in each manufacturing process step. In this study, the hardness of the surface, the cutting force test and the metal analysis were performed to clarify the influence of manufacturing process parameters.

본 연구에서는 polypropylene glycol(PPG) 을 이용한 수분산 폴리우레탄에 카제인을 그래프트 합성한 다음 카본블랙을 분산하여 발생하는 변화를 분석하였다. 이를 위해 카제인을 그래프트한 수분산 폴리우레탄 (PUD와 CPUD’s) 시료를 준비한뒤 카본블랙이 분산된 CPCB’s 시료를 준비하였다. 준비된 시료를 이용하여 인장강도를 측정 한 결과 카제인이 높게 함유된 CPUD3 가 3.01 kgf/㎟ 로 인장강도가 증가하였으며, CPCB’s 에서는 카본 블랙이 증가할수록 인장강도가 2.54 kgf/㎟ 로 낮게 측정되었다. 연신율은 카제인이 적게 함유된 PUD 시료가 278 % 로 측정되었으며, CPCB’s에서는 CP3CB4 가 157% 로 측정되었다. 내마모성은 CPUD3 시료가 36.97 mg.loss, CP3CB4가 41.11 mg.loss 로 표면 강도가 측정되었다. 내용제성은 PUD’s 시료와 CPCB’s 시료 양쪽 모두 물성변화가 없음을 확인 할 수 있었다.

깨다시 꽃게(Ovalipes punctatus)는 갑각류로서 우리나라에서 잡히는 매끈 꽃겟속, 주름 꽃 겟속, 톱날 꽃겟속, 민 꽃겟속, 두갈래 민꽃겟속 들 중에 하나이다. 대부분의 꽃게는 가공되지 않은 상태로 찜 또는 찜육 등 반 가공 형태로 산업화 되었지만 최근에 게로부터 생리활성을 나타내는 펩타이드를 생산하는 연구가 발표되고 있다. 본 연구는 항산화 기능성을 나타내는 펩타이드를 선별하고 생산 최저공정 확립에 연구를 수행 하였다. 사용된 효소 alcalase, bromelain, flavourzyme, neutrase, papain, protamex들 중에서 bromelain으로 생산된 꽃게육 단백질 가수분해물이 가장 높은 활성을 보여 주었다. 꽃게육 단백질의 bromelain 가수분해물의 펩타이드들의 분자량 분포는 500-3,200 Da로서 7 종류의 이상의 펩타이드들로 구성되었다. 가수분해물의 구성아미노산 분포는 항산화 기능성에 관련된 소수성 아미노산은 전체 42.54%를 차지하였다. 가수분해물의 최적 생산 수율 조건을 확립하기 위하여 공정 조건, 효소 반응 온도 40-60℃, pH 6-8, 효소의 농도 1–3%(w/v)로 표면반응 분석법을 수행한 결과 효소 반응온도 55℃, 반응 pH 6.5, 효소의 양은 3%(w/v)에서 결정되었다. 최적 조건에서 단백질 가수분해도는 최대 71.60%에 도달하였다.

In this study, baked rice donuts with added psyllium seed husk were manufactured and their quality and retrogradation characteristics were investigated. Control (Con) was made only with wheat flour; Psyllium seed husk in the amount of 8, 12, 16 and 20 grams was added to make rice donuts (P8, P12, P16 and P20). Higher amounts of psyllium seed husk reduced the moisture loss and baking loss, and increased the moisture content and water holding capacity of the donuts. The specific volume of Con was the highest of all the groups. As the amount of psyllium seed husk increased, the lightness and yellowness of the crumb decreased, and the redness of the crumb increased. Hardness also increased as the amount of psyllium seed husk increased. The hardness of P16 was the most similar to that of Con. The scanning electron microscopy images also identified that the structure of the donuts got denser as the amount of psyllium seed husk increased. Rate constant (k) of the rice donuts with psyllium seed husk were lower than that of Con. In conclusion, it is considered that P16 is the sample that is the most similar to Con in terms of texture, but the retrogradation was more retarded in P16 than Con.

Using a high pressure homonizer, we report on the electrochemical performance of Li4Ti5O12(LTO) particles manufactured as anode active material for lithium ion battery. High-pressure synthesis processing is performed under conditions in which the mole fraction of Li/Ti is 0.9, the synthesis pressure is 2,000 bar and the numbers of passings-through are 5, 7 and 10. The observed X-ray diffraction patterns show that pure LTO is manufactured when the number of passings-through is 10. It is found from scanning electron microscopy analysis that the average size of synthesized particles decreases as the number of passings-through increases. LiCoO2-based active cathode materials are used to fabricate several coin half/full cells and their battery characteristics such as lifetime, rate capability and charge transfer resistance are then estimated, revealing quite good electrochemical performance of the LTO particles as an effective anode active material for lithium secondary batteries.

This study focuses on the fabrication of a WC/Co composite powder from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere for the recycling of WC/Co hardmetal. Mixed powders are manufactured by mechanically milling the oxide powder of WC-13 wt% Co hardmetal scrap and carbon black with varying powder/ball weight ratios. The oxide powder of WC-13 wt% Co hardmetal scrap consists of WO3 and CoWO4. The mixed powder mechanically milled at a lower powder/ball weight ratio (high mechanical milling energy) has a more rapid carbothermal reduction reaction in the formation of WC and Co phases compared with that mechanically milled at a higher powder/ball weight ratio (lower mechanical milling energy). The WC/Co composite powder is fabricated at 900℃ for 6 h from the oxide of WC/Co hardmetal scrap using solid carbon in a hydrogen gas atmosphere. The fabricated WC/Co composite powder has a particle size of approximately 0.25-0.5 μm.

In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M HNO3, a reaction temperature of 75℃, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, NaBH4 and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

F-containing TiO2 nanopowders are synthesized using simple wet processes (precipitation-based and hydrothermal) from ammonium hexafluorotitanate (AHFT, (NH4)2TiF6) as a precursor to apply as a photocatalyst for the degradation of rhodamine B (RhB). The surface properties of the prepared samples are evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results confirm that the synthesized anatase TiO2 has sphere-like shapes, with numerous small nanoparticles containing fluorine on the surface. The photocatalytic activity of F-containing TiO2 compared with F-free TiO2 is characterized by measuring the degradation of RhB using a xenon lamp. The photocatalytic degradation of F-containing TiO2 exhibits improved photocatalytic activity, based on the positive effects of adsorbed F ions on the surface.

The microstructure and mechanical characteristics of SUS630 specimens fabricated using the direct energy deposition (DED) process are investigated. In DED, several process parameters such as laser scan speed, chamber gas flow, powder carrier gas flow, and powder feed rate are kept fixed; the laser power is changed as 150 W, 180 W, and 210 W. As the laser power increases, the surface becomes smooth, the thickness uniformity improves, and the size and number of pores decreases. With the increase in laser power, the hardness deviation decreases and the average hardness increases. The microstructure of the material is columnar; pores are formed preferentially along the columnar interface. The lath-martensite phase governs the overall microstructure. The volumetric fraction of the retained austenite phase is measured to increase with the increase of laser input power.