scholarly journals Critical ignition conditions in exothermically reacting systems: first-order reactions

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170145 ◽  
Author(s):  
Valeriy Yu. Filimonov
Keyword(s):  
Experimental Data ◽  
Order Reaction ◽  
Critical Conditions ◽  
Conversion Degree ◽  
First Order ◽  
Critical Ignition ◽  
Reacting Systems ◽  
Plane Temperature ◽  
Temperature Time ◽  
Good Agreement

In this paper, the comparative analysis of the thermal explosion (TE) critical conditions on the planes temperature–conversion degree and temperature–time was conducted. It was established that the ignition criteria are almost identical only at relatively small values of Todes parameter. Otherwise, the results of critical conditions analysis on the plane temperature–conversion degree may be wrong. The asymptotic method of critical conditions calculation for the first-order reactions was proposed (taking into account the reactant consumption). The degeneration conditions of TE were determined. The calculation of critical conditions for specific first-order reaction was made. The comparison of the analytical results obtained with the results of numerical calculations and experimental data showed that they are in good agreement.

PENYERAPAN GAS KARBONDIOKSIDA (CO 2 ) DALAM BIOGAS DENGAN LARUTAN Ca(OH)2

EKUILIBIUM ◽  
2015 ◽  
Vol 14 (1) ◽  
Author(s):  
Paryanto Paryanto
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Order Reaction ◽  
First Order Reaction ◽  
Glass Ball ◽  
Carbon Dioxide Content ◽  
First Order ◽  
Constant Rate ◽  
Rate Of Reaction ◽  
Reduce Carbon Dioxide

<p>Abstract: Carbon dioxide content in biogas produced by fermentation is still high. Because of<br />that, biogas need a process purification to reduce carbon dioxide content. In this work, Ca(OH)2<br />solution was contacted with biogas in a column for reducing the CO<br />2<br />content. This research<br />studied the effect of packing type used in absorber column on the rate of CO<br />2<br />reduction. Based<br />on experimental data and modelling, it was found that the reaction between CO<br />2<br />followed first order reaction. The constant of rate reaction was affected by the packing type<br />which using glass ball, plastic pipe, ceramic, wood, and clay roof, the constant rate were 0.781,<br />0.464, 0.916, 0.637, and 0.987 min<br />Keywords: Biogas, CO<br />2<br />, Ca(OH)2<br />-1<br />, respectively.<br />, absorber, rate of reaction</p>

Pseudo-Homogenous Kinetics Model for the Synthesis of Dimethyl Carbonate from Urea and Methanol with Heterogeneous Catalyst

2011 ◽  
Vol 233-235 ◽  
pp. 481-486
Author(s):  
Wen Bo Zhao ◽  
Ning Zhao ◽  
Fu Kui Xiao ◽  
Wei Wei
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Dimethyl Carbonate ◽  
Side Reaction ◽  
Order Reaction ◽  
Zero Order ◽  
Kinetics Model ◽  
First Order ◽  
Zero Order Reaction ◽  
Kinetics Of

The synthesis of dimethyl carbonate (DMC) from urea and methanol includes two main reactions: one amino of urea is substituted by methoxy to produce the intermediate methyl carbamate (MC) which further converts to DMC via reaction with methanol again. In a stainless steel autoclave, the kinetics of these reactions was separately investigated without catalyst and with Zn-containing catalyst. Without catalyst, for the first reaction, the reaction kinetics can be described as first order with respect to the concentrations of methanol and methyl carbamate (MC), respectively. For the second reaction, the results exhibit characteristics of zero-order reaction. Over Zn-containing catalyst, the first reaction is neglected in the kinetics model since its rate is much faster than second reaction. After the optimization of reaction condition, the macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model, in which a side reaction of DMC synthesis is incorporated since it decreases the yield of DMC drastically at high temperature. The activation energy of the reaction from MC to DMC is 104 KJ/mol while that of the side reaction of DMC is 135 KJ/mol.

scholarly journals Dynamic modeling of ships towed by kite

2018 ◽  
pp. 8-10 ◽  
Author(s):  
Nedeleg Bigi ◽  
Morgann Behrel ◽  
Kostia Roncin ◽  
Jean-Baptiste Leroux ◽  
Alain Neme ◽  
...  
Keyword(s):  
Experimental Data ◽  
Strong Coupling ◽  
Dynamic Modeling ◽  
Equations Of Motion ◽  
Critical Conditions ◽  
Ship Motions ◽  
Zero Mass ◽  
Coupling Methods ◽  
Good Agreement

A dynamic kite flight can affect ship motions. Ship equations of motion associated with the analytical zero-mass kite model are developed. Aiming a realistic amplitude modeling of the kite excitation, a linear modification of the aerodynamic kite specs with the turning rate of the kite velocity heading is proposed. A good agreement with experimental data is obtained. Equations of motion are solved on a reaching path alternatively with a weak and a strong coupling between the ship and the kite. Differences between the two coupling methods become significant when a harmonic of the kite excitation approaches the natural roll frequency of the ship. For the presented case of study, these critical conditions can be avoided with longer tethers or larger kite trajectories.

scholarly journals Alcoholysis of Nyamplung Seed Oil Using Potassium Carbonate Catalyst

2006 ◽  
Vol 6 (2) ◽  
pp. 66
Author(s):  
Sofiyah Sofiyah
Keyword(s):  
Potassium Carbonate ◽  
Potassium Hydroxide ◽  
Seed Oil ◽  
Catalyst Concentration ◽  
Order Reaction ◽  
First Order ◽  
Rate Of Reaction ◽  
Glycerine Content ◽  
Sodium And Potassium ◽  
Good Agreement

The production of glycerol and ester by alcoholysis of vegetable oils has been widely studied. Various catalysts, such as sodium and potassium hydroxide and sulfuric acid have been used to increase the rate of reaction. This preliminary research studied the possibility of using potassium carbonate catalyst. The experiment was conducted in an autoclave. A certain amount of nyamplung seed oil was poured into the autoclave and then the heater was switched on to heat up the oil to the required temperature of reaction. Besides, a mixture of ethanol and potassium carbonate was heated in a flask equipped with condenser to form ethanolate. As soon as the required temperature was reached, the ethanolate was quickly put into the autoclave containing the nyamplung seed oil. The temperature of the reaction was kept constant for a period of time. At the end of each process, a sample was withdrawn and analyzed for its glycerine content by acetin method. The variables studied were reaction time and catalyst concentration. The experimental data were evaluated by applying pseudo homogeneous approach. It was found that data were in good agreement with first order reaction with respect to nyamplung seed oil. Using an equivalent ratio of 5.1 ethanol to nyamplung seed oil, a temperature of lOQoC,and an agitation speed of 150 rpm, the favorable catalyst concentration was found to be at 0.008 gram of potassium carbonate per gram of nyamplung seed oil. Under this condition, the glyceride conversion was 0.5159 in 75 min.

Photodegradation of some Furocoumarins in Ethanol under UV Irradiation

2016 ◽  
Vol 683 ◽  
pp. 402-405
Author(s):  
Natalya G. Bryantseva ◽  
Olga N. Tchaikovskaya ◽  
Vlada S. Kraiukhina ◽  
Maria Gómez ◽  
Jose Luis Gómez
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Kinetic Model ◽  
Kinetic Parameter ◽  
Bulk Solution ◽  
Order Kinetic ◽  
First Order ◽  
Operational Variables ◽  
Pseudo First Order ◽  
Good Agreement

Photodegradation of 5-Methoxypsoralen (5-MOP), 4', 5'-dimethyl-3,4-cyclogeksilpsoralen (KC5) and 4'-methyl-3,4 cycloheptylpsoralen (KC4) has been carried out in an XeBr exilamps, both in the presence of H2O2, and a kinetic model, which explains the dependence of the pseudo-first order kinetic parameter on the substrate concentration and other operational variables, has been developed. In the development of the model, mass transfer of 5-MOP, KC5 and KC4from the bulk solution to the wall of the vessel was assumed as the step determining the rate of the photodegradation process, which successfully explains some singularities observed in the experimental results.By fitting the experimental data to the model, a detailed study of the influence of all operational variables on the pseudo-first order kinetic parameter has been done, in good agreement with the model hypotheses.

Fabrication of Self-Organized TiO2 Nanotubes by Anodization and its Photocatalytic Properties

2011 ◽  
Vol 322 ◽  
pp. 209-212
Author(s):  
Tian Yu Wu ◽  
Xin Tan ◽  
Juan Ru Huang ◽  
Tao Yu ◽  
Lin Zhao
Keyword(s):  
Apparent Rate Constant ◽  
Photocatalytic Performance ◽  
Anatase Phase ◽  
Order Reaction ◽  
Nanotube Arrays ◽  
Photocatalytic Reaction ◽  
First Order ◽  
Self Organized ◽  
Titania Nanotube Arrays ◽  
Good Agreement

Titania nanotube arrays(TNT) was extensively studied due to its good photocatalytic activity. This article focused on the fabrication of highly ordered TNTs. TNTs were fabricated in an electrolyte of ethylene glycol(EG), water and NH4F for 1, 2, 3, 4h and then annealed at 400°C. The influence of anodic time on the morphology and photocatalytic performance of TNT was investigated. The results indicated that the TNT could be successfully fabricated by using the electrolyte, and the diameter and length of TNT were about approximately 140nm, 5-13μm, separately. Furthermore, the results also showed anatase phase was dominant, TNT with good morphology displayed good photocatalitic properties. When the initial concentration of Rhodamine B(RhB) was 7×10−6mol﹒L−1, the removal of RhB reached 88.1% by TNT anodized for 2h with length of 9.5μm. In addition, the results showed that the photocatalytic reaction fitting the first-order reaction in good agreement with the literature, and the apparent rate constant(kapp) was 0.0251 min-1(the length of 9.5μm)．

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

2014 ◽  
Vol 28 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Lech W. Szajdak ◽  
Jerzy Lipiec ◽  
Anna Siczek ◽  
Artur Nosalewicz ◽  
Urszula Majewska
Keyword(s):  
Reaction Rate ◽  
Inorganic Compounds ◽  
Model Performance ◽  
Order Reaction ◽  
First Order Reaction ◽  
Order Kinetic ◽  
Time Data ◽  
First Order ◽  
Concentration Changes ◽  
Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

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