• Title/Summary/Keyword: C1 reduction

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Extrusion Effect on the Reduction of Fumonisin $B_1$ in Corn Grits with/or without Sugars (당류 첨가 및 비첨가 옥수수에서의 Fumonisin $B_1$ 감소에 미치는 Extrusion 효과)

  • ;Lloyd B. Bullerman
    • The Korean Journal of Food And Nutrition
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    • v.13 no.6
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    • pp.547-552
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    • 2000
  • Corn grits spiked with fumonisin B$_1$(FB$_1$) at a level of 5 $\mu$g/g were extrusion cooked in a co-rotating twin screw extruder at different temperatures(140, 160, 18$0^{\circ}C$) and screw speed(80, 100, 120 rpm). About 41~45% of the spiked FB$_1$ was lost when the corn grits were extruded. Both the barrel temperature and the screw speed. however, did not significantly affect the FBI reduction in extruded corn grits. More reduction of FB$_1$ was found in the presence of glucose than with fructose or sucrose when the corn grits were extruded with sugar at 14$0^{\circ}C$, 120 rpm. About 51, 34 and 19% of spiked FB$_1$ were remained in extruded corn grits with glucose at levels of 2.5%, 5%, and 7.5%, respectively.

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Effects of Squealer Rim Height on Aerodynamic Losses Downstream of a High-Turning Turbine Rotor Blade

  • Lee, Sang-Woo;Chae, Byoung-Joo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.160-167
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    • 2008
  • The effects of squealer rim height on three-dimensional flows and aerodynamic losses downstream of a high-turning turbine rotor blade have been investigated for a typical tip gap-to-chord ratio of h/c=2.0%. The squealer rim height-to-chord ratio is changed to be $h_{st}/c$=0.00(plane tip), 1.37, 2.75, 5.51, and 8.26%. Results show that as $h_{st}/c$ increases, the tip leakage vortex tends to be weakened and the interaction between the tip leakage vortex and the passage vortex becomes less severe. The squealer rim height plays an important role in the reduction of aerodynamic loss when $h_{st}/c{\leq}2.75%$. In the case of $h_{st}/c{\geq}5.51%$, higher squealer rim cannot provide an effective reduction in aerodynamic loss. The aerodynamic loss reduction by increasing $h_{st}/c$ is limited only to the near-tip region within a quarter of the span from the casing wall.

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Hollow Reinforced Concrete Bridge Column Systems with Reinforcement Details for Material Quantity Reduction: I. Development and Verification (물량저감 철근상세를 갖는 중공 철근콘크리트 교각 시스템: I. 개발 및 검증)

  • Kim, Tae-Hoon;Lee, Jae-Hoon;Shin, Hyun-Mock
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.1
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    • pp.1-8
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    • 2014
  • The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction. The proposed reinforcement details have economic feasibility and rationality and make construction periods shorter. A model of hollow reinforced concrete bridge columns was tested under a constant axial load and a quasi-static cyclically reversed horizontal load. As a result, proposed reinforcement details for material quantity reduction were equal to existing reinforcement details in terms of required performance. The companion paper presents the experimental and analytical study for the performance assessment of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction.

Reaction of Potassium 2-Thexyl-1,3,2-dioxaborinane Hydride with Selected Organic Compounds Containing Representative Functional Groups

  • Jin Soon Cha;Sung Eun Lee
    • Bulletin of the Korean Chemical Society
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    • v.13 no.5
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    • pp.531-537
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    • 1992
  • The approximate rates and stoichiometry of the reaction of excess potassium 2-thexyl-1,3,2-dioxaborinane hydride(KTDBNH) with 55 selected compounds containing representative functional groups under standardized conditions (tetrahydrofuran, TEX>$0^{\circ}C$, reagent : compound=4 : 1) was examined in order to define the characteristics of the reagent for selective reductions. Benzyl alcohol and phenol evolve hydrogen immediately. However, primary, secondary and tertiary alcohols evolve hydrogen slowly, and the rate of hydrogen evolution is in order of $1^{\circ}$> $2^{\circ}$> $3^{\circ}$. n-Hexylamine is inert toward the reagent, whereas the thiols examined evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to give the corresponding alcohols. Cinnamaldehyde is rapidly reduced to cinnamyl alcohol, and further reduction is slow under these conditions. The reaction with p-benzoquinone dose not show a clean reduction, but anthraquinone is cleanly reduced to 9,10-dihydro-9,10-anthracenediol. Carboxylic acids liberate hydrogen immediately, further reduction is very slow. Cyclic anhydrides slowly consume 2 equiv of hydride, corresponding to reduction to the caboxylic acid and alcohol stages. Acid chlorides, esters, and lactones are rapidly and quantitatively reduced to the corresponding carbinols. Epoxides consume 1 equiv hydride slowly. Primary amides evolve 1 equiv of hydrogen readily, but further reduction is slow. Tertiary amides are also reduced slowly. Both aliphatic and aromatic nitriles consume 1 equiv of hydride rapidly, but further hydride uptake is slow. Analysis of the reaction mixture with 2,4-dinitrophenylhydrazine yields 64% of caproaldehyde and 87% of benzaldehyde, respectively. 1-Nitropropane utilizes 2 equiv of hydride, one for hydrogen evolution and the other for reduction. Other nitrogen compounds examined are also reduced slowly. Cyclohexanone oxime undergoes slow reduction to N-cyclohexylhydroxyamine. Pyridine ring is slowly attacked. Disulfides examined are reduced readily to the correponding thiols with rapid evolution of 1 equiv hydrogen. Dimethyl sulfoxide is reduced slowly to dimethyl sulfide, whereas the reduction of diphenyl sulfone is very slow. Sulfonic acids only liberate hydrogen quantitatively without any reduction. Finally, cyclohexyl tosylate is inert to this reagent. Consequently, potassium 2-thexyl-1,3,2-dioxaborinane hydride, a monoalkyldialkoxyborohydride, shows a unique reducing characteristics. The reducing power of this reagent exists somewhere between trialkylborohydrides and trialkoxyborohydride. Therefore, the reagent should find a useful application in organic synthesis, especially in the field of selective reduction.

Preparation of α-Linked 6-Deoxy-D-altro-heptopyranosidic Residues

  • 신영숙;천근호;Shin, E. Nam;Gerald O. Aspinall
    • Bulletin of the Korean Chemical Society
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    • v.16 no.7
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    • pp.625-630
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    • 1995
  • α-Linked D-altropyranosidic derivatives were obtained by configurational change at C-3 of α-D-mannopyranosides as the key step in preparation of allyl and methyl α-D-glycopyranosides of 6-deoxy-D-altro-heptose. The manno-altro conversion was effected by sequential reactions of Swern oxidation and stereoselective borohydride reduction. Allyl 4,6-O-benzylidene-2-O-p-methoxybenzyl-α-D-mannopyranoside was transformed to the corresponding altropyranoside via 3-oxo-arabino-hexopyranoside. Allyl 7-O-benzyl-6-deoxy-3,4-O-isopropylidene-α-D-altro-heptopyranoside has been prepared as a glycosyl acceptor to be coupled with β-D-GlcpNAc-(1→3)-α-D-Galp glycosyl donor for the synthesis of an O-antigen repeating unit of Campylobacter jejuni serotypes O:23 and O:36. Stereoselective borohydride reduction also succeeded in yielding methyl 2,4,7-tri-O-benzyl-6-deoxy-α-D-altro-heptopyranoside from the corresponding 3-oxo-α-D-arabino-heptopyranoside. C-6 Homologation was achieved by sequential reactions of cyanide displacement of 6-sulphonates, reduction of the resulting heptopyranosidurononitrile with diisobutylaluminum hydride, hydrolysis of the imine, and further reduction with sodium borohydride.

Post-earthquake capacity evaluation of R/C buildings based on pseudo-dynamic tests

  • Kang, Dae-Eon;Yi, Waon-Ho
    • Structural Engineering and Mechanics
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    • v.24 no.1
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    • pp.91-105
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    • 2006
  • In this paper, post-earthquake capacity evaluation method of reinforced concrete buildings was studied. Substructure pseudo-dynamic test and static loading test of first story column in a four-story R/C building was carried out in order to investigate the validity of the evaluation method proposed in the Damage Assessment Guideline (JBDPA 2001). In pseudo-dynamic test, different levels of damage were induced in the specimens by pre-loading, and input levels of seismic motion, at which the specimens reached to the ultimate stage, were examined. From the experimental result, no significant difference in damage levels such as residual crack width between the specimens under static and pseudo-dynamic loading was found. It is shown that the seismic capacity reduction factors ${\eta}$ can provide a reasonable estimation of post-earthquake seismic capacity of R/C buildings suffered earthquakes.

Influence of Sintering Parameters on the Mechanical Performance of PM Steels Pre-alloyed with Chromium

  • Bergman, Ola;Lindqvist, Bjorn;Bengtsson, Sven
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.280-281
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    • 2006
  • Powder grades pre-alloyed with 1.5-3 wt% chromium can be successfully sintered at the conventional temperature $1120^{\circ}C$ although well-monitored sintering atmospheres are required to avoid oxidation. Mechanical properties of the Cr-alloyed PM grades are enhanced by a higher sintering temperature in the range $1120-1250^{\circ}C$, due to positive effects from pore rounding, increased density and more effective oxide reduction. Astaloy CrM (Fe-3 wt% Cr-0.5 wt% Mo) with 0.6 wt% graphite added obtains an ultimate tensile strength of 1470 MPa and an impact strength of 31 J at density $7.1\;g/cm^3$, after sintering at $1250^{\circ}C$ followed by cooling at $2.5^{\circ}C/s$ and tempering.

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Preparation of Nickel Fine Powders from Aqueous Nickel Chloride Solution Containing Organic Solvents (유기용매를 함유한 염화니켈 수용액으로부터 Ni 미분말 제조)

  • 최은영;이상근;이윤복;문영태;김광호
    • Journal of the Korean Ceramic Society
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    • v.40 no.5
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    • pp.488-493
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    • 2003
  • Nickel fine powders were prepared from aqueous nickel chloride solution containing organic solvents and the effect of the addition of the organic solvent on the formation of nickel powders were investigated. All products were spherical particles in the range of 0.1∼1.0 $\mu\textrm{m}$ and the agglomeration of particles did not appear. In case of containing 40 vol% of 1-propanol, the particle size reduction and homogeneity of the powders were remarkable. The average particle size and the specific surface area of the powders produced with 40 vol% of 1-propanol were 0.3 $\mu\textrm{m}$ and 16.4 m$^2$/g respectively. The reduction reaction time by hydrazine decreased with increasing of the content of 1-propanol, and was 5 min for 40 vol% of 1-propanol. The oxidation of synthesized nickel powders occurred at 320$^{\circ}C$ and weight loss at 300$^{\circ}C$ was due to dehydration of Ni(OH)$_2$.

Fabrication and properties of Calcium-aluminate electride thin films using by sol-gel process (Sol-Gel 법을 이용한 칼슘-알루미네이트계 전자화물 박막의 제조와 특성)

  • Kim, K.H.;Park, J.S.;Chae, J.H.;Seo, W.S.;So, S.M.;Kim, T.K.;Kim, H.S.;Lee, B.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.6
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    • pp.262-266
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    • 2010
  • The Calcium-aluminate electride thin films on the quartz substrates was coated by sol-gel process. The crystallization of the C12A7 thin film was observed at $800^{\circ}C$ and high density C12A7 thin film was achieved on heat treatment at $1,200^{\circ}C$ for 1 hour. The reduction heat treatment of C12A7 thin film could be converted from insulator to conductor and the electrical conductivity was 120 S/cm in the C12A7 thin film heat treated at $1,200^{\circ}C$ with $H_2$ gas for 48 hours.

A Study on Reduction of Food Waste (음식물 쓰레기 소멸화에 관한 연구)

  • 서명교;이상봉;이국의;이상훈
    • Journal of Environmental Health Sciences
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    • v.27 no.1
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    • pp.14-19
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    • 2001
  • The physical and chemical transformation and reduction degree of food waste were investigated in a food waste reduction machine using thermophilic bacteria. The first operation of the reduction machine for grain, vegetables, fishes and flesh wastes proceeded during three weeks. The first and second reduction percentages of the wastes were 98.3% and 93.2%, respectively. The residue of food waste was composed of fruits, fish, and vegetables. The temperature distribution of the reduction machine ranged between 30 and 6$0^{\circ}C$ appropriate for growth of thermophilic bacteria. At initial stage the pH in the reduction machine decreased with organic acids produced, but increased as the organic acids decomposed by different thermophilic bacteria. In the reduction machine, the moisture content of the food waste was reduced from 80-90% to 10-20% after 24 hours, and the salinity of residue was 0.29% after the second operation. The degree of odor was most high between 2 and 4 hours.

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