• Title/Summary/Keyword: Weight Loss 무게감소

Search Result 185, Processing Time 0.126 seconds

Synthesis and Properties of Photocurable Epoxy Modified Acrylates Using Half-Ester Acrylates (하프-에스터 아크릴레이트를 이용한 광경화형 에폭시 변성 아크렐레이트의 합성과 물성)

  • 김동국;임진규;김우근;허정림
    • Polymer(Korea)
    • /
    • v.28 no.6
    • /
    • pp.531-537
    • /
    • 2004
  • Various half-ester acrylates were prepared from anhydrides and 2-hydroxyethyl acrylate. Photocurable epoxy modified acrylates were prepared from synthesized half-ester acrylate and neopentylglycol diglycidylether. Physical properties such as hardness, yellowing, tensile strength and elongation were tested and compared as the structure of oligomer in cured-film differs. It was found that viscosity of neopentylglycol diglycidylether-hexahydrophthalic anhydride (NP-HA) was highest. Hardness and tensile strength of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride were better than those of other photocrosslinted epoxy acrylates. And 5% weight loss temperature of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride was higher than those of other photocrosslinked epoxy acrylates. Value of yellow index of photocrosslinked neopentylglycol diglycidyl ether-succinic anhydride (NP-SA) was lower than the other products.

Desulfurization characteristics of low sulfur coal by mild pyrolysis (저온 열분해에 의한 저유황 석탄의 탈황 특성)

  • Park, KyeSung;Yun, ChaeKyung;Nam, YoungWoo
    • Clean Technology
    • /
    • v.8 no.1
    • /
    • pp.1-9
    • /
    • 2002
  • Mild pyrolysis of four different coals (two bituminous coals and two Korean antracite) was investigated. Desulfurization characteristics, weight loss and variation of heating values were studied. As operating variables of experiment, pyrolysis temperature($350{\sim}550^{\circ}C$), pyrolysis time(5~20 min.) and particle size(0~3.55mm) were examined. The maximum sulfur removal rate of bituminous coal and anthracite were 38% and 28%, respectively. The optimum mild pyrolysis conditions were 10~15 min for pyrolysis time and $450{\sim}550^{\circ}C$ for pyrolysis temperature. The mild pyrolysis was effective to reduce organic sulfur content. Heating values of char per mass after pyrolysis increased about 5% compared to raw coal. The effect of coal particle size on the desulfurization was not observed.

  • PDF

Effect of Hydrophilic Polymers on the Release of BCNU from BCNU-loaded PLGA Wafer (친수성 고분자가 BCNU 함유 PLGA 웨이퍼로부터 BCNU의 방출에 미치는 효과)

  • 안태군;강희정;문대식;이진수;성하수
    • Polymer(Korea)
    • /
    • v.26 no.5
    • /
    • pp.670-679
    • /
    • 2002
  • 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) is one of the effective chemotherapeutic agents which has been used clinically for treating malignant glioma. Poly(D,L-lactide-co-glycolide) (PLGA, molecular weight: 20000 g/mole. mole ratio of lactide to glycolide 75 : 15) is a well known biodegradable polymer used as a drug carrier for drug delivery system. In this study, we investigated the BCNU release behaviour of BCNU-loaded PLGA wafers containing poly (N-vinylpyrrolidone) (PVP) or polyethyleneoxide (PEO) and the effect of hydrophilic polymers incoporated in the wafers. BCNU-loaded PLGA microparticles with or without hydrophilic polymers were prepared by a spray drying method and fabricated into wafers by direct compression. Encapsulation efficiency of BCNU-loaded PLGA microparticles containing PVP and PEO was 85 ∼ 97% and crystallinity of BCNU encapsulated in PLGA decreased significantly initial release amount and release rate of BCNU increased with the increasing PVP or PEO amount. Morphological change and mass loss of wafers during the release test were confirmed that hydration and degradation of PLGA would be facilitated with an increase of hydrophilic polymers.

Effect of Cabbage Powder on Baking Properties of White Breads (양배추 분말 첨가가 제빵 적성에 미치는 영향)

  • Lee, Seon-Ho
    • Food Science and Preservation
    • /
    • v.17 no.5
    • /
    • pp.674-680
    • /
    • 2010
  • This study was carried out to investigate quality characteristics of white breads with cabbage powder(CP) (0, 2.5, 5.0, 7.5 and 10.0%). L-value was significantly decreased by addition of CP, but a and b-values were increased(p<0.05). The degree of pH of dough and bread weight increased with increasing CP concentration, while bread volume, specific volume, and baking loss rate became reduced. The hardness of the breads added with CP was higher than that of the control group. Also, In sensory analysis, the breads with CP showed generally low scores in color, flavor, taste, texture and overall acceptability compared with the control. Taken together, the 2.5%, 5.0% treatment showed similar results with the control group, as compared to other treatments. Addition of CP influenced the color, bread volume and other rheological properties, which is disadvantageous for the quality of white bread. However, compared with the control group, up to 5% CP substitution for flour didn't show significant defferences in sensory test.

The Characterization of Pyrophyllite Based Ceramic Reactive Media for Permeable Reactive Barriers (투수성반응벽체 적용을 위한 납석광물 기반 세라믹 반응매질의 특성평가)

  • Cho, Kanghee;Kim, Hyunsoo;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
    • /
    • v.31 no.4
    • /
    • pp.227-234
    • /
    • 2018
  • In this work, we have prepared the reactive media with the pyrophyllite based using ceramic extrusion process. The characteristics of pyrophyllite were analyzed using XRD, XRF, DSC-TGA and Zeta-potential analysis. The study of pyrophyllite based ceramic reactive media were conducted under various roasting temperature (500 to $1,300^{\circ}C$) conditions. With increasing the roasting temperature, strength was increased but BET surface area was decreased. Thermally treated pyrophyllite were analyzed by means of weight loss and structural changes as detected by using XRD, DSC-TGA and SEM analysis. Pyrophyllite primarily transforms to pyrophyllite dehydroxylate after roasting at $1,000^{\circ}C$. Pyrophyllite dehydroxylate transforms to mullite and cristobalite at $1,300^{\circ}C$. This study demonstrates that pyrophyllite could be used as a reactive media for ceramic support layers from Permeable Reactive Barriers.

A Study on the Sound Insulation Characteristics of Honeycomb Panels for Offshore Plants (해양플랜트용 허니컴 패널의 차음 특성 연구)

  • Jung, Jae-Deok;Hong, Suk-Yoon;Song, Jee-Hun;Kwon, Hyun-Wung
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.23 no.7
    • /
    • pp.948-955
    • /
    • 2017
  • Currently, porous materials (e.g., mineral wool) are the core materials used in offshore plant panels, but in spite of their superb acoustic performance, these items must be replaced for environmental reasons. A honeycomb structure is widely used throughout the industry because of its high strength-to-weight ratio. However, research in terms of noise and vibration is minimal. An acoustic study should be conducted by taking advantage of honeycomb structures to replace porous materials. In this study, a simulation was performed assuming that a honeycomb panel is a superposition of symmetric mode and antisymmetric mode. Reliability was verified by comparing a simulation results based on a theory with a experimental results, and the possibility of the panel as a core material was evaluated by studying the sound insulation characteristics of a honeycomb. As the panel thickness increased, the coincidence frequency shifted to low frequency. As the angle between horizontal line and oblique wall and cell-size decreases, the sound insulation performance is improved. And as the cell-wall thickness increased, the sound insulation performance improved.

Preparation and Characterization of Nanocrystalline Spinel Ferrites by Chemical Co-precipitation (화학적 공침법을 이용한 침상형 페라이트 합성)

  • Shen, Jiao-Wen;Lim, Yun-Hui;Jo, Young-Min
    • Applied Chemistry for Engineering
    • /
    • v.22 no.2
    • /
    • pp.185-189
    • /
    • 2011
  • In this work, nano-sized M-ferrites (M=Co, Ni, Cu, Zn) for the decomposition of carbon dioxide were synthesized by the chemical co-precipitation. From the thermogravimetric analysis, it was clear that the maximum weight loss of each sample took place below $350^{\circ}C$. High temperature calcination resulted in more systematic crystallines, smaller specific surface area and larger particle size. An analysis by FTIR in the range of $375{\sim}406cm^{-1}$ revealed the presence of chelates at the octahedral site, which implies the formation of spinel structure in the ferrites. The current work showed that a $500^{\circ}C$ is the optimum heat treatment temperature of metal ferrites for $CO_2$ decomposition reaction.

Solid Particle Erosion Behavior of Inconel 625 Thermal Spray Coating Layers (Inconel 625 열용사 코팅 층의 고상입자 침식 거동)

  • Park, Il-Cho;Han, Min-Su
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.27 no.4
    • /
    • pp.521-528
    • /
    • 2021
  • In this study, to repair damaged economizer fin tubes on ships, sealing treatment was performed after applying arc thermal spray coating technology using Inconel 625. A solid particle erosion (SPE) experiment was conducted according to ASTM G76-05 to evaluate the durability of the substrate, thermal spray coating (TSC), and thermal spray coating+sealing treatment (TSC+Sealing) specimens. The surface damage shape was observed using a scanning electron microscope and 3D laser microscope, and the durability was evaluated through the weight loss and surface roughness analysis. Consequently, the durability of the substrate was superior to that of TSC and TSC+Sealing, which was believed to be owing to numerous pore defects in the TSC layer. In addition, the mechanism of solid particle erosion damage was accompanied by plastic deformation and fatigue, which were the characteristics of ductile materials in the case of the substrate, and the tendency of brittle fracture in the case of TSC and TSC+Sealing was confirmed.

Lithium Recovery from NCM Lithium Ion Battery by Hydrogen Reduction Followed by Water Leaching (NCM계 리튬이온 배터리 양극재의 수소환원과 수침출에 의한 리튬 회수)

  • So-Yeong Lee;So-Yeon Lee;Dae-Hyeon Lee;Ho-Sang Sohn
    • Resources Recycling
    • /
    • v.33 no.1
    • /
    • pp.15-21
    • /
    • 2024
  • The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H2O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.

Quality standard of Agaricus bisporus in a market and changes of mushroom quality during storage (유통 양송이버섯의 등급별 품질규격 및 저장기간별 품질 변화)

  • Lee, Chan-Jung;Oh, Jin-A;Cheong, Jong-Chun;Jhune, Chang-Sung;Moon, Ji-Won;Kong, Won-Sik;Suh, Jang-Sun
    • Journal of Mushroom
    • /
    • v.11 no.1
    • /
    • pp.41-45
    • /
    • 2013
  • This study was carried out to improve standardization of agricultural products and investigate quality changes during preservation at various treatments. The standardization does much to improve merchantable quality, distribution efficiency and fair dealings by shipping of the standard agricultural products. Mushrooms notified as the standard are five; Pleurotus ostreatus, Pleurotus eryngii, Flammulina velutipes, Agaricus bisporus and Ganoderma lucidum. But many farmers are suffering from strict standards. Therefore, modification of these standards is required to fit farmhouse situations. Fruit-body weight of A, B and C grades of the marketed Agaricus bisporus was 19.3g, 12.2g and 10.4, respectively. Average pileus diameter of A grades was 43.3mm but B and C grades did not show significant difference. Average stipe length of A, B and C grades was 9.8mm, 13.1mm and 11.6mm, and stipes thick was the highest in A grades. The weight loss rate of stipe cutting of Agaricus bisporus was 12.6% in harvested mushrooms and the rate of stipe cutting length was 60.8%. The diameter of Agaricus bisporus stored for 5 days was 3.5~4.5cm but decreased rapidly in 15 days. The weight loss rate of the high temperature samples lowered rapidly than that of the low temperature samples. Conversely, the L value of the low temperature samples was higher than that of the high temperature samples.