• Title/Summary/Keyword: Index properties

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A Study on the Mechanical Properties Optimization of Solid Propellant (고체 추진제의 기계물성 최적화 연구)

  • Choi, Yongkyu;Ryu, Taeha;Kim, Nakhyun;Kim, Jeongeun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.6
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    • pp.91-97
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    • 2015
  • The limit values of mechanical properties(MPs) of HTPB/AP/Al Solid Propellant was reviewed according to the rocket motor development procedures and the in-process values of MPs were analyzed by the tool of Process Capability Index. Based on finding the dependency among MPs, the optimization is proposed for reducing the properties defects and for improving the rocket grain safeties.

Studies on Mechanical Interfacial Properties of Kevlar-29 Fibers Reinforced Composites (Kevlar-29 섬유강화 복합재료의 기계적 계면 특성 연구)

  • Park, Soo-Jin;Seo, Min-Kang;Ma, Tae-Jun;Lee, Jae-Rock
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.158-162
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    • 2001
  • The effects of chemical treatment on Kevlar-29 fibers have been studied in a composite system. The surface characteristics of the Kevlar-29 fibers were characterized by pH, acid-base value and X-ray photoelectron spectroscopy (XPS). The mechanical interfacial properties of final composites were studied by interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). Also, the impact properties of the composites were investigated in the differentiating studies between initiation and propagation energies, and ductile index (DI) along with maximum farce and total energy. It was found that the chemical treatment with phosphoric acid ($H_3PO_4$) solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improving the mechanical interfacial strength of the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force in a composite system.

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Starch Treatment for the Improvement of Physical Properties of Hanji( II ) -Relationships between the physical properties and the surface characteristics of Hanji treated with various starches- (한지의 강도적 성질 개선을 위한 전분류 처리 ( 제 2 보 ) -전분처리 한지의 표면과 강도적 성질과의 관계 -)

  • Beak, Seung-Hee;Yoon, Seung-Lak;Jo, Jong-Soo
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.38 no.2 s.115
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    • pp.22-34
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    • 2006
  • To improve the mechanical properties of Hanji, starches such as maize, konyaku, and wheat powders were added at various concentrations in the manufacturing processes of Hanji. The effect of starches on the physical properties of Hanji was as follows. Filling rates of surface of hanji were increased with the increase of the concentration of starch. Hanji surface were completely filled at the 3.0% konyaku treatment. Konyaku powder showed higher filling rates than maize and wheat powder. The breaking length was increased with the increase of filling rates. Konyaku powder showed the highest breaking length: Tear index of hanji treated with maize and wheat powder were a little improved but that of hanji treated with konyaku powder were a little decreased compared to non-treated hanji. In conclusion, starch treatment showed the increase of the breaking length, but no effect on tear index.

The Effects of the Cutting Length of Paper Mulberry Bast Fiber on Pulping and Hanji Properties(I) - White bast of Korea grown paper mulberry - (닥나무 인피섬유의 절단장이 펄프화 및 한지의 물성에 미치는 영향(제1보) - 국산 닥 백피의 특성 -)

  • Lim, Gang-Hyouk;Choi, Tae-Ho
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.40 no.2
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    • pp.57-64
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    • 2008
  • In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

Viscosity and Dynamic Rheological Properties of Job's-tears as a Function of Moisture Content (수분함량에 따른 율무가루의 점도변화 및 동적물성 특성에 관한 연구)

  • Yoon, Won-Byung;Kim, Byung-Yong;Shin, Dong-Hoon
    • Korean Journal of Food Science and Technology
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    • v.29 no.5
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    • pp.932-938
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    • 1997
  • Changes in viscosity and dynamic theological properties of Job's-tears were measured by Bohlin dynamic tester as a function of moisture, and measurement was performed within a linear viscoelastic range. The result of the shear stress vs shear rate of Job's-tears at different moisture contents $(50{\sim}75%)$ was applied to mathematical models and Herschel-Bulkley model showed the highest correlation coefficient. Lower moisture content (55%) produced higher yield stress and consistency index, but lower flow behavior index, whereas higher moisture content showed reverse effects. Job's-tears with $50{\sim}70%$ moisture contents showed a higher storage modulus (G') than loss modulus (G') at all frequencies, showing a higher concentrated polymer characteristics. However, higher moisture content (>75%) showed crossover point between G' and G', and frequency dependency. As the moisture content was increased, the amount of viscoelastic properties such as G', G', complex viscosity decreased during heating, and initial temperature and miximum value of viscoelastic properties shifted to higher temperatures, representing the moisture-dependence of Job's-tears upon theological properties.

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Functional Properties of Maillard Conjugates Made from Whey Protein Isolate and Inulin (분리유청단백질-이눌린 유래 마이야르 공액체의 기능적 특성 연구)

  • Kim, Yeon-Woo;Lee, Se-Hee;Lee, Won-Jae
    • Journal of Dairy Science and Biotechnology
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    • v.40 no.4
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    • pp.143-150
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    • 2022
  • Maillard conjugates are formed by covalent bonds between proteins and polysaccharides. Understanding the functional properties of Maillard conjugates, including emulsifying and antioxidant properties, can be crucial when Maillard conjugates are used in processed foods. This study aimed to manufacture whey protein isolate (WPI)/Inulin Maillard conjugates and investigate how manufacturing variables including heating temperature and pH affect the functional properties of Maillard conjugates. The surface properties, emulsifying properties, and antioxidant properties of Maillard conjugates were assessed by varying heating temperature and pH. The grafting degree of WPI/Inulin Maillard conjugates increased with increasing pH and heating temperature, indicating enhanced conjugation efficiency. Surface hydrophobicity, emulsifying properties (including emulsifying activity index and emulsifying stability index), and ABTS radical scavenging ability of WPI/Inulin Maillard conjugates increased as pH and heating temperature were increased. In conclusion, WPI/Inulin Maillard conjugates were successfully manufactured, and pH and heating temperature were critical factors in enhancing Maillard conjugate functional properties.

The Effect of White Water Components on Mechanical Properties of Linerboard (라이너지 공정수의 구성 성분이 종이의 물성에 미치는 영향)

  • 윤혜정;류정용;송봉근;조미선
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.36 no.1
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    • pp.9-15
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    • 2004
  • Micro inorganic solids and dissolved materials contained in the white water of linerboard process was obtained by centrifugation, and their characteristics were analyzed along with their effects on the mechanical properties of linerboard. Micro inorganic materials had little influence on tensile index and ZDT of UKP sheets. They showed rather a positive effect on mechanical properties of KOCC sheets due to adsorbed polymer. Mechanical properties of KOCC sheets decreased remarkably when the concentration of dissolved materials increased especially above 4000 ppm.

Relationship Between Physical Properties and Compression Index for Marine Clay (해성점토의 물리적 특성과 압축지수의 상관성)

  • 김동후;김기웅;백영식
    • Journal of the Korean Geotechnical Society
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    • v.19 no.6
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    • pp.371-378
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    • 2003
  • The compression index of clay distributed in the west and south coast of the Korean Peninsula had been studied. Compression index was obtained from the conventional consolidation test, and was conducted accordingly to obtain the field virgin compression curve by means of Schmertmann's graphical correction. To examine a correlation closely between physical properties of soils($e_o$, LL, w) and compression index(Cc), linen. and non-linear regression analysis were employed based on the data collected from tests. The conclusions are as follows. The compression index obtained by means of Schmereann's graphical correction is about 1.16 times for the value of original oedometer test curve for U/D samples. Non-liner regression curve was preferable to establish a correlation equation rather than linear regression curve. All derived equations so far achieved have been summarized and given. However, linear equation is better for practical use so that part by part simplified linear equations were also suggested alternatively together with their own non-linear regression curve.

Rheological Properties of Gelatinized Potato Starch (겔라틴화(化)된 감자 전분(澱粉)의 리올로지 특성(特性))

  • Chang, Young Il;Chang, Kyu Seob;Park, Young Duck
    • Korean Journal of Agricultural Science
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    • v.18 no.1
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    • pp.41-48
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    • 1991
  • Rheological properties of gelatinized potato starch were investigated with Brookfield wide-gap viscometer at various conditions. The gelatinized potato starch at 3-7% showed a pseudoplastic behavior with yield stress, and presented thixotropic properties with time-dependent structural decays. The consistency index and yield stress of gelatinized starch were proportional to starch concentration but inversely proportional to measurement temperature, and the flow behavior index did not show constant relationship. The consistency index and yield stress of the gelatinized starch on addition of phosphate decreased as the flow behavior index increased. The values of activation energy at initial and equilibrium were 1.52 kcal/g.mole and 127 kcal/g.mole, respectively.

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Ganoderma lucidum균 전처리를 이용한 볏짚의 상압.소다펄프화

  • 주용찬;강진하
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.4
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    • pp.51-60
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    • 2002
  • This study was carried out to develop the biochemical pulping method to enhance energy saving and decrease the capital cost through the soda pulping under atmospheric pressure (100%). Nonwood substrates, rice straw, were pretreated by white-rot fungi, Ganoderma Iucidum. It has acquired several basic data that can be applied in bio-soda pulping. The results of this study were as follow. Without any nutrients or with glucose, N and glucose+N the weight losses of rice straws inoculated by Canoderma Iucidum were 8.5~29.8%, 9.3~32% 11.8~30.1% and 11.8~24.4% respectively for 5, 10, 15, 20, 25 and 30 days incubation. The more extending incubation periods, the more increasing weight losses. The yield of untreated rice saw was 54.8% after pulping. When any nutrients was not added or glucose, N and glucose+N were added for the pretreatment, the total yields were ranged 50.6~38.5%, 48.6~34.4%, 47.2~38.4% and 49.5~42.6% respectively for 5, 10, 15, 20, 25 and 30 days incubation. The yields were gradually decreased based on extending of incubation. The physical properties of rice straw soda pulps without fungal treatment, the density, breaking length, burst index, tear index and folding endurance were 0.24 g/$\textrm{cm}^3$, 2.32 km, 0.91 kPa $m^2$/g, 56.7 mN.$m^2$/g and 35 times, respectively. After pretreatment without any nutrients or with glucose, N and glucose+N as nutrients the density was 0.27~0.30 g/$\textrm{cm}^3$, the breaking length 3.14~5.25 km, burst index 1.42~2.78 kPa.$\textrm{m}^2$/g, tear index45.8~64.5 mN.$\textrm{m}^2$/g and folding endurance 47~288 times at all incubating periods when pulping was done. The physical properties were increased with the increasing incubation periods. However, when glucose+N was added, the physical properties were shown superior results each incubating duration.