• 제목/요약/키워드: chemical factory

검색결과 143건 처리시간 0.039초

Advances in Biochemistry and Microbial Production of Squalene and Its Derivatives

  • Ghimire, Gopal Prasad;Nguyen, Huy Thuan;Koirala, Niranjan;Sohng, Jae Kyung
    • Journal of Microbiology and Biotechnology
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    • 제26권3호
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    • pp.441-451
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    • 2016
  • Squalene is a linear triterpene formed via the MVA or MEP biosynthetic pathway and is widely distributed in bacteria, fungi, algae, plants, and animals. Metabolically, squalene is used not only as a precursor in the synthesis of complex secondary metabolites such as sterols, hormones, and vitamins, but also as a carbon source in aerobic and anaerobic fermentation in microorganisms. Owing to the increasing roles of squalene as an antioxidant, anticancer, and anti-inflammatory agent, the demand for this chemical is highly urgent. As a result, with the exception of traditional methods of the isolation of squalene from animals (shark liver oil) and plants, biotechnological methods using microorganisms as producers have afforded increased yield and productivity, but a reduction in progress. In this paper, we first review the biosynthetic routes of squalene and its typical derivatives, particularly the squalene synthase route. Second, typical biotechnological methods for the enhanced production of squalene using microbial cell factories are summarized and classified. Finally, the outline and discussion of the novel trend in the production of squalene with several updated events to 2015 are presented.

지하 프리캐스트 박스 암거의 구조적 성능 개선에 관한 연구 (Improvement of Structural Performance for the Precast Box Culvert)

  • 조병완;태기호;이계삼
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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    • pp.393-398
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    • 2000
  • To use concrete box culverts effectively, precast goods are manufactured at a factory, then linked and anchored with prestressing tendon at a field. However, the corrosion of rebar and prestressing tendon in the box culverts utilizing portland cement concrete is issued when the cracks occur at a underground water level. It has been reported that reported that expansive concrete, compared with portland cement concrete, has many structural advantages such as increasing capacity of watertight, controling initial crack and improving durability due to its property of expansion. During flexure test with RC beam made from expansive concrete, in the case of a constant section of concrete element, the lower steel ratio is, and in the case of a constant steel ratio, the more incremental the section of concrete element, the more incremental the amount of chemical prestress by expansive concrete is. At the segment of the box culverts using expansive concrete, the numbers of crack and its gap is reduced, and ultimate load and initial crack load is much larger than the segment at which expansive concrete is nor used. Also lay-out of tendon with a curvature generate upward force so that deflection is reduced. Through the whole procedure, it could be confirmed that performance precast box culvert by means of using expansive concrete is improved.

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에너지 절약형 공기압 시스템 특성에 관한 연구 (A Study on the Energy Saving Type Pneumatic System Characteristics)

  • 김형의;김동수;강보식;성백주
    • 연구논문집
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    • 통권25호
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    • pp.91-98
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    • 1995
  • Recently, improving the energy efficiency of a pneumatic system and reducing the consumption of compressed air were a concern of scholars at domestic and abroad. The using fields of a pneumatic system are widely used in factory automation of manufacturing line, chemical factories with explosiveness danger and petroleum industries etc. In particular, pneumatic cylinder is applied to feeding work of workpiece. jig tools and press mechanism, reciprocation and rotary motion with rack and pinion. In this study, the experimental apparatus consisted to pneumatic cylinder, dual supply pressure regulator and solenoid valve. The dual supply pressure regulator connected to outlet port of solenoid valve. The supply pressure($4.5kg_f/cm^2$) of compressed air goes into the rodless chamber 1 to drive the piston rod forward which is named working stage. The supply pressure ($2kg_f/cm^2$) of compressed air goes into the rod chamber 2 to drive the piston rod backward which is named no-working stage. Accordingly, the research results of this study can be obtained to Energy-Saving Effects of the compressed air about 35%.

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Struvite 결정화 공정을 이용한 새우가공폐수처리 (Treatment of shrimp processing wastewater using struvite crystallization process)

  • 정병곤
    • 수산해양기술연구
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    • 제52권3호
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    • pp.271-275
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    • 2016
  • Recently, pollution problem in coastal water has become more serious and pollution including red tide serves as a main reason for reduction of fishes resources. Particularly, nutrients such as nitrogen and phosphorus are the most serious pollutants. Normally, biological wastewater treatment process is used in removing such nutrients. However, it is difficult to adopt the biological wastewater treatment process to a small-scale fish processing factory in case of using seawater as wash water. Thus, removing nutrients through struvite crystallization is investigated in this study for treating shrimp processing wastewater. Experiments were conducted by varying molar ratio of $Mg^{2+}:NH^4-N:PO^4-P$ from 1:1:1 to 2:1:1. It can be concluded that optimum molar ratio is 1:1:1. Struvite crystallization process is compared with chemical coagulation process using PAC and struvite crystallization process is proven as the more effective process in removing nutrients from wastewater. In view of results obtained from these experiments, struvite crystallization process is a promising method in removing nitrogen and phosphorus from wastewater; however, not so good in removing organics. Thus, struvite crystallization process is suitable as the pre-treatment process in treating shrimp processing wastewater and additional biological process is needed to remove organics.

용접 불티 차단막의 방염 및 난연성능 평가 (An Evaluation of Flame and Fire Retardant Performance for Welding Blanket)

  • 이근원;권오승;하동명
    • 한국화재소방학회논문지
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    • 제15권2호
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    • pp.53-58
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    • 2001
  • 본 연구에서는 조선 및 화학공장 등 산업현장에서 용접·용단작업 공정에서 비산 되는 불티에 의한 화재 예방을 위하여 불티 차단막에 관한 방염 및 난연 성능 평가를 실시하였다. 방염성능 실험결과 기존제품의 용접불티 차단막 6종 모두 충분한 방염성능을 갖고 있었다. 그러나, 용접·용단 불꽃에 의한 난연성 실험 결과 섬유유리에 수지코팅한 제품 2종은 용접·용단 불티에 대한 화재예방성능이 부족한 것으로 나타났다. 용접 불티 차단막의 최소산소지수의 국내기준은 30이상으로 고려하는 것이 좋을 것으로 사료된다. 용접 불티 차단막의 성능향상을 위한 제속적인 연구가 필요하며, 방염 및 난연성능 기술지침 개발의 기초자료로서 활용될 수 있을 것으로 사료된다.

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유기 다공성 소재의 흡유 효과 (Oil Absorption Effects of Organic Porous Materials)

  • 강영구;한상범
    • 한국안전학회지
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    • 제21권1호
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    • pp.86-91
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    • 2006
  • Oil spills caused by the accidents have been occurred from house and factory waste, grounded tanker, the rupture of storage tank and oil pipelines, the deterioration of various industrial facilities, etc. Many oil spills result in contamination of shorelines and workplace. Fire and explosion may happen from these spills. There are several technologies used for clean-up application, which include use of oil dispersing agents, absorbents, solidifiers, booms and skimmers by physical, chemical, and biological methods. Methods for oil spill clean-up operation are classified into the absorption type, gel type and self-swelling type. Porous materials with oil absorptive properties are classified into micropore, mesopore, and macropore depending on their pore sizes. Recently, new porous materials with smaller size have been developed, but the selective oil absorption in water-in-oil interface demonstrates the macro pore size. In this study oil absorption effects were evaluated using the organic porous materials with a complex function of gel type and swelling type. Samples were subjected to analysis by FT-IR spectroscopy and were characterized in terms of gel formation and morphologies. Oil sorption capacity, pressure retention force and gel strength were also measured. From these results, the physicochemical reactivity before and after gelation was verified and the industrial applications of clean-up operation were suggested.

Biophysical and mechanical response of keratinous fibres to changes in temperature, humidity and damage

  • Skinner, Richard;Tucker, Ian;Pudney, Paul;Hannah, Teresa;Leray, Yann;Matisson, Gregory;Bell, Fraser;Devine, Karen;Carpenter, P.;Oikawa, T.;Cornwell, Paul
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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    • pp.200-200
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    • 2003
  • Intact mammalian hair and wool fibres are multi-compartmental composite materials consisting of a sulphur-rich outer protective cuticle layer surrounding elongated, highly keratinized, cortex cells. The cortex cells themselves are made up of crystalline, filamentous, low-sulphur a-helical keratin molecules embedded in a matrix of highly cross-linked, globular high-sulphur keratins. It is the structurally organised and highly disulphide cross-linked nature of these materials that provides them with their remarkable mechanical properties. However these mechanical properties are sensitive to environmental conditions such as water content, temperature and chemical treatment and the importance of their ultra-structural arrangements to overall mechanical properties in different environments is still not fully understood.(omitted)

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유전알고리즘과 신경회로망을 이용한 플라즈마 식각공정의 모델링과 최적제어입력탐색 (Modeling and optimal control input tracking using neural network and genetic algorithm in plasma etching process)

  • 고택범;차상엽;유정식;우광방;문대식;곽규환;김정곤;장호승
    • 대한전기학회논문지
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    • 제45권1호
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    • pp.113-122
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    • 1996
  • As integrity of semiconductor device is increased, accurate and efficient modeling and recipe generation of semiconductor fabrication procsses are necessary. Among the major semiconductor manufacturing processes, dry etc- hing process using gas plasma and accelerated ion is widely used. The process involves a variety of the chemical and physical effects of gas and accelerated ions. Despite the increased popularity, the complex internal characteristics made efficient modeling difficult. Because of difficulty to determine the control input for the desired output, the recipe generation depends largely on experiences of the experts with several trial and error presently. In this paper, the optimal control of the etching is carried out in the following two phases. First, the optimal neural network models for etching process are developed with genetic algorithm utilizing the input and output data obtained by experiments. In the second phase, search for optimal control inputs in performed by means of using the optimal neural network developed together with genetic algorithm. The results of study indicate that the predictive capabilities of the neural network models are superior to that of the statistical models which have been widely utilized in the semiconductor factory lines. Search for optimal control inputs using genetic algorithm is proved to be efficient by experiments. (author). refs., figs., tabs.

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부산물석회 성토지반의 지반공학적 특성 (Geotechnical Characteristics of a Waste Lime Embankment)

  • 홍승서;김영석;배규진
    • 지질공학
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    • 제25권4호
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    • pp.547-555
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    • 2015
  • 연구에서는 부산물석회 혼합토를 이용하여 조성된 시험성토체에 대한 지반공학적 특성에 대하여 고찰하였다. 연구에 사용한 부산물석회는 인천의 화학공장에서 소다회(Na2CO3)를 생산하는 공정에서 부수적으로 발생하는 부산물이다. 현장조성 후 3년이 경과된 후에 시험성토체를 대상으로 현장밀도, 평판재하시험, 동적콘관입시험, 현장 CBR시험을 수행하였다. 시험결과로부터 성토재료로써의 부산물석회 혼합토의 지반공학적 특성이 제시되었다.

반도체 산업의 작업환경과 질병의 경험들 (Working Environment and Experiences of Diseases in Semiconductor Industry)

  • 공유정옥
    • 한국산업보건학회지
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    • 제22권1호
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    • pp.32-41
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    • 2012
  • Objectives: Information of chemical in electronics industry has not been known enough, although workers' health hazards by chemicals in this industry have been regarded serious. The who always contribute to reveal and control the health hazards and risks in electronics industry have not been the industry but the occupational or environmental victims and grassroot organizations. The similar phenomena can be observed in Korea. Methods: The experiences of individual workers on the occuapational safety and health in semiconductor factory were heard separately and integrated with related literatures. Results:: The first part of this article is largely based on the memories and experiences of individual workers of semiconductor factories, mainly from S semiconductor. Common features of those experiences can be a good resource for detail understanding of the workplace, especially under the situation without any transparent disclosure of information by the governments or the companies. The second part of this article deals with several factors to be considered for control of exposure in workplace; characteristics of workplace and workforce, types of chemicals used, and the way of using the chemicals. Then the current social issues on work-relatedness of cancers of S semiconductor workers are presented briefly. Conclusions: As a conclusion, current OSH situations and issues in Korean electronics industry raise the need of changes in OSH culture. General adaptation of precautionary principle, internalization of costs, and extended responsibility of producers are needed urgently. The OSH professionals both in public and private sectors should support these agendas under their social obligation to protect workers' health.