• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.546-550
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• 2014

Relative reactivity of various carbonyl and acid derivatives in MPV-type (Meerwein-Ponndorf-Verley) reduction with an DIBAL(F) model has been studied via DFT and MP2 methods. Free energies of initial adduct formation (-Gadd) of DIBAL(F) model and carbonyls are in the order of amide < ester < aldehyde < ketone < acid chloride; in the alan-amide adduct, the developed positive charge at carbonyl carbon is expected to be stabilized by amide resonance, but in the acid chloride adduct it is destabilized by inductive effect of chloride. However the TS barrier energies (${\Delta}G_{TS}$) for the MPV-type hydride reduction of the carbonyl adducts are in the order of aldehyde < ketone < acid chloride << ester < amide; presumably decreasing order of electrophilicity of carbonyl carbon at adducts, which is well correlated with experimental data. It is noted that the relative reactivity of carbonyl derivatives in MPV-type reduction with DIBAL(X) is not governed by the alan-adduct formation energies, but follows the order of electrophilicity of carbonyl carbon of transition states.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.17-18
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• 2019

In this study, the initial strength reduction of coal gasification slag fine powders was confirmed through previous studies when used in cement formulations. It is also confirmed that the blast furnace slag is mixed with cementitious coal blast furnace slag, which is similar to coal gasification slag, to incorporate gypsum in order to prevent initial strength deterioration. In order to analyze the reactivity of coal gasification slag by desulfurization gypsum, the formation of hydrates and their reactivity at early ages were confirmed by electron microscope. In order to confirm the reactivity, the gypsum samples were prepared with unincorporated type and 2% mixed type. Experimental results showed that 2% of the desulfurized gypsum specimens reacted more actively than the uninjured ones.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2133-2150
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• 2021

In this work, Esfahan light water subcritical reactor (ELWSCR) is analysed using experimental and theoretical diagnostic methods. Important neutronic parameters of the system such as prompt neutron lifetime, delayed neutron fraction, prompt neutron decay constant, negative reactivity of the core, fuel and moderator temperature coefficient of reactivity, and overall and local void coefficient of reactivity are estimated. Also, neutron flux distribution, reflector saving, water level effect, and lattice pitch of the core including operating point of the facility are studied in details. Theoretical results are calculated by MCNPX and measurements are performed utilizing zero power reactor noise method. Detailed descriptions of the results are explained in the text.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1277-1288
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• 2018

In this work, the reactor kinetics capability is used to compute the design safety parameters in a PWR due to complete loss of coolant flow during protected and unprotected accidents. A thermal-hydraulic code coupled with a point reactor kinetic model are used for these calculations; where kinetics parameters have been developed from the neutronic SRAC code to provide inputs to RELAP5-3D code to calculate parameters related to safety and guarantee that they meet the regulatory requirements. In RELAP5-3D the reactivity feedback is computed by both separable and tabular models. The results show the importance of the reactivity feedback on calculating the power which is the key parameter that controls the clad and fuel temperatures to maintain them below their melting point and therefore prevent core melt. In addition, extending modeling capability from separable to tabular model has nonremarkable influence on calculated safety parameters.

• Journal of Hydrogen and New Energy
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• v.20 no.3
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• pp.245-255
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• 2009

Effect of CO$_2$ concentration on reduction reactivity of oxygen carrier particles for chemical-looping combustor were investigated. Four particles, NiO/bentonite, OCN601-650, OCN702-1100, OCN702-1250, were used as oxygen carrier particles and two kinds of gases (CH$_4$, 5%, N$_2$ balance and CH$_4$ 5%, CO$_2$ balance) were used as reactants for reduction. For all oxygen carrier particles, higher maximum conversion, reduction rate, oxygen transfer capacity, and oxygen transfer rate were achieved when we used N$_2$ balance gas. OCN601-650 particle showed higher oxygen transfer rate for all gases than other particles, and therefore we selected OCN601-650 particle as the best candidate. For all particles, lower carbon depositions were observed when we used CO$_2$ balance gas.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2880-2900
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• 2012

Robot programming often sparks students' interest in programming, but it is not easy for them to program both procedure and reactivity of robot movements that are essential requirements. In this study, we reviewed in detail a new programming language, State-Based Squeak. It allows novice students to implement both procedure and reactivity of robots easily. The effect of this new language on robot programming education was also examined using a group of 28 middle school students. According to the results of analyzing the students' understanding of programming, reading and programming abilities the group that used State-Based Squeak (the experimental group) showed a higher completion ratio than the other (control) group. The significance of this study is that a robot programming language has been developed that addresses the concepts of both procedure and reactivity in such a way that middle school students can more easily learn how to program robots, something that is often difficult to attempt even for professional programmers.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1251-1255
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• 2003

Second-order rate constants have been determined spectrophotometrically for the reaction of phenyl 4-nitrophenyl carbonate with a series of primary amines in $H_2O$ containing 20 mol % DMSO at 25.0 ${\circ}$C. The Bronsted-type plot is linear with a ${\beta}_{nuc}\;0.69 {\pm} 0.04$, which is slightly smaller than the ${\beta}_{nuc}$ values for the reactions of 4-nitrophenyl acetate ( $\beta_{nuc}= 0.82 {\pm} 0.03$) and benzoate ( $\beta_{nuc} = 0.76 {\pm} 0.01$), indicating that the reaction proceeds through a tetrahedral zwitterionic intermediate $T^{\pm}$. The carbonate is more reactive than the corresponding acetate and benzoate. The changing Me (or Ph) to PhO has resulted in a decrease in the ${\beta}_{nuc}$ value without changing the reaction mechanism but an increase in the reactivity. The electronic effect of the substituent in the nonleaving group appears to be responsible for the enhanced reactivity of the carbonate compared with the corresponding acetate and benzoate.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.72-79
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• 2001

The selective catalytic oxidation of toxic aromatic solvents (benzene, toluene, ethylbenzene, and styrene) and their mixtures were studied on a $Pt/{\;}{\gamma}-Al_2O_3$ catalyst at temperature ranging from $160~350^{\circ}C$. The deep conversion of aromatic solvents was increased as the inlet concentration was decreased and the reaction temperature was increased. The reactivity increases in order benzene > toluene > ethylbenzene > styrene. In mixture, remarkable effects on reaction rate and selectivity have been evidence ; the strongest inhibition effect is shown by styrene and increase in a reverse order with respect to that of reactivity. The inhibition effect was increased in order styrene > ethylbenzene > toluzene > benzene. This trend is due to the competition adsorption between the two or three reactants on the oxidized catalyst. Also, the deep conversion change of benzene was a small in tertiary mixtures(including of benzene and styrene) comparing with conversion characteristics of binary mixture with styrene. This result was due to small concentration of styrene. which had very strong inhibition effect.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.604-609
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• 1995

The relative dissociation constants of 4-substituted bicyclo[2,2,2]octane-1-carboxylic acids, 4-substituted quinuclidines, and 3-and 4-substituted pyridines were collected from a number of sources. In order to understand the actual substituent effects with a combination of inductive effect (σI) and resonance effect (σR) components. The DSP correlation has been employed statistically for each of the p-and m-series. The inductive effect from the m-position was 1.2 times more effective than that from the p-position and the requirement of σR+ for the best-fit led to the conclusion that pyridine system belongs to the σ+-class reactivity. Also compared with results from Yukawa-Tsuno's LArSR treatment and relevant treatment.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.610-611
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• 1989