scholarly journals ASSESSING FIRST-ORDER DEPENDENCE OF THERMOLYTIC HGR ON GLYCOLATE AT LOW GLYCOLATE CONCENTRATIONS

2021 ◽  
Author(s):  
SETH HUNTER
Keyword(s):  
First Order ◽  
Order Dependence

EXCHANGE BETWEEN THALLOUS AND THALLIC IONS IN THE PRESENCE OF SULPHATE ION

1958 ◽  
Vol 36 (1) ◽  
pp. 167-170 ◽  
Author(s):  
D. R. Wiles
Keyword(s):  
Exchange Reaction ◽  
Higher Order ◽  
Transfer Mechanism ◽  
Ion Concentration ◽  
First Order ◽  
Order Dependence

The rates of the exchange reaction between thallous and thallic ions have been measured as a function of sulphate ion concentration, at constant acidity. At high sulphate concentrations, the results agree with those of Brubaker and Mickel, indicating second- and higher-order dependence of the rate on sulphate ion concentration. At low sulphate concentrations, pure first-order dependence on sulphate is found. The inhibitive effect found in some systems is absent. A bridge-transfer mechanism is suggested.

The Decomposition of Sodium Nitrite Solutions in Aqueous Sulphuric and Perchloric Acids

1963 ◽  
Vol 16 (6) ◽  
pp. 927 ◽  
Author(s):  
NS Bayliss ◽  
DW Watts
Keyword(s):  
Aqueous Solutions ◽  
Acid Composition ◽  
Sodium Nitrite ◽  
Decomposition Rate ◽  
Rate Constants ◽  
First Order ◽  
Order Dependence ◽  
Gaseous Products ◽  
Kinetics Of

The kinetics of the decomposition of aqueous solutions of sulphuric and perchloric acids containing sodium nitrite have been investigated at a number of temperatures. The technique involved flushing the decomposing solutions with dry nitrogen to remove the gaseous products. A first-order dependence of decomposition rate on "analytical nitrite" was found, the rate constants being dependent on the solvent acid composition.

scholarly journals Kinetics and Mechanism of Oxidation of Diethanolamine and Triethanolamine by Potassium Ferrate

2011 ◽  
Vol 8 (2) ◽  
pp. 903-909 ◽  
Author(s):  
Shan Jinhuan ◽  
Zhang Jiying
Keyword(s):  
Activation Parameters ◽  
Rate Equations ◽  
Potassium Ferrate ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Order Dependence ◽  
Rate Determining Step ◽  
Thermodynamic Activation Parameters ◽  
Plausible Mechanism ◽  
Kinetics Of

The kinetics of oxidation of diethanolamine and triethanolamine by potassium ferrate(VI)in alkaline liquids at a constant ionic strength has been studied spectrophotometrically in the temperature range of 278.2K-293.2K. The reaction shows first order dependence on potassium ferrate(VI), first order dependence on each reductant, The observed rate constant (kobs) decreases with the increase in [OH-], the reaction is negative fraction order with respect to [OH-]. A plausible mechanism is proposed and the rate equations derived from the mechanism can explain all the experimental results. The rate constants of the rate-determining step and the thermodynamic activation parameters are calculated.

CO-CATALYSIS IN FRIEDEL–CRAFTS REACTIONS: VI. POLYMERIZATION OF 2-BUTENE BY BORON FLUORIDE – METHANOL

1963 ◽  
Vol 41 (4) ◽  
pp. 932-936 ◽  
Author(s):  
H. R. Allcock ◽  
A. M. Eastham
Keyword(s):  
Molecular Weight ◽  
Catalyst Concentration ◽  
Ethylene Dichloride ◽  
Low Molecular Weight ◽  
Boron Fluoride ◽  
First Order ◽  
Order Dependence ◽  
Rate Of Polymerization ◽  
Cis And Trans

2-Butene is polymerized by boron fluoride and methanol in ethylene dichloride solution at ordinary temperatures to give very low molecular weight polymers. The rate of polymerization shows exactly the same dependence on catalyst concentration as did the rate of isomerization of the cis- and trans-2-butenes, i.e. first order both in free boron fluoride and in the boron fluoride – methanol complex. The polymerization, however, shows a first-order dependence in olefin over a concentration range where the isomerization is, experimentally, virtually independent of the olefin concentration.

scholarly journals Comparing kinetic profiles between bifunctional and binary type of Zn(salen)-based catalysts for organic carbonate formation

2014 ◽  
Vol 10 ◽  
pp. 1817-1825 ◽  
Author(s):  
Carmen Martín ◽  
Arjan W Kleij
Keyword(s):  
Catalyst Concentration ◽  
Catalyst System ◽  
Bifunctional Catalyst ◽  
Cyclic Carbonates ◽  
First Order ◽  
Order Dependence ◽  
Carbonate Formation ◽  
Salen Complexes ◽  
Organic Carbonate ◽  
Binary Catalyst

Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu4I and a bifunctional system Zn(salpyr)·MeI with a built-in nucleophile. The latter system demonstrates an apparent second-order dependence on the bifunctional catalyst concentration and thus follows a different, bimetallic mechanism as opposed to the binary catalyst that is connected with a first-order dependence on the catalyst concentration and a monometallic mechanism.

scholarly journals Kinetics and Mechanism of the Oxidation of Naphthol Green B by Peroxydisulphate Ion in Aqueous Acidic Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
B. Myek ◽  
S. O. Idris ◽  
J. F. Iyun
Keyword(s):  
Acidic Medium ◽  
Reaction Medium ◽  
Intermediate Complex ◽  
Kinetic Investigation ◽  
Hydrogen Ions ◽  
First Order ◽  
Order Dependence ◽  
Naphthol Green B ◽  
Kinetics Of ◽  
Aqueous Acidic Medium

The kinetics of the oxidation of naphthol green B (NGB3−) by peroxydisulphate ion has been carried out in aqueous acidic medium at λmax of 700 nm, T=23±1°C, and I=0.50 mol dm−3 (NaCl). The reaction shows a first-order dependence on oxidant and reductant concentration, respectively. The stoichiometry of the NGB—S2O82- reaction is 1 : 2. Change in hydrogen ions concentration of the reaction medium has no effect on the rate of the reaction. Added cations and anions decreased the rate of the reaction. The results of spectroscopic and kinetic investigation indicate that no intermediate complex is probably formed in the course of this reaction.

scholarly journals Kinetics and Mechanism of Oxidation ofL-Cystine by Hexacyanoferrate(III) in Alkaline Medium

2009 ◽  
Vol 6 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Annapurna Nowduri ◽  
Kalyan Kumar Adari ◽  
Nageswara Rao Gollapalli ◽  
Vani Parvataneni
Keyword(s):  
Alkaline Medium ◽  
Oxidation Product ◽  
Experimental Results ◽  
Cysteic Acid ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Order Dependence ◽  
Plausible Mechanism ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

Kinetics of oxidation ofL-cystine by hexacyanoferrate(III) was studied in alkaline medium at 30 °C. The reaction was followed spectrophotometrically at λmax = 420 nm. The reaction was found to be first order dependence each on [HCF(III)] and [cystine]. It was found that the rate of the reaction increases with increase in [OH-]. The oxidation product of the reaction was found to be cysteic acid. A plausible mechanism has been proposed to account for the experimental results.

scholarly journals Mechanical Impedance Control in the Human Arm While Manually Transporting an Open-Top Fluid Filled Dish

2011 ◽  
Vol 8 (3-4) ◽  
pp. 429-440 ◽  
Author(s):  
Navit Roth ◽  
Rami Seliktar ◽  
Joseph Mizrahi
Keyword(s):  
Angular Velocity ◽  
Impedance Control ◽  
Wrist Joint ◽  
Mechanical Impedance ◽  
Shoulder Girdle ◽  
Compensatory Mechanisms ◽  
First Order ◽  
Order Dependence ◽  
Future Design ◽  
Shoulder Joints

The present study deals with stabilizing aspects of a hand-held dish filled with liquid while walking steadily. This is an attempt to decipher the neuro-muscular strategies employed and the mechanical responses of the arm during certain tasks of manual materials handling. The experimental configuration included a cup and the test-subject’s hand as an ‘end-effector’ of a serial three-link system representing the upper limb. These links are connected together by the wrist, elbow and shoulder joints. The tested subjects walked at constant speed on a treadmill while aiming to minimize liquid spillage from the cup. The motion of the limb and shoulder girdle served as inputs to a model to reveal the impedance adjustments during the simultaneous control of grasping and walking under ordinary conditions, and when one of the joints is affected. A regressive function used to express stiffness, included first-order dependence on angle and on angular velocity. The function used for damping included first-order dependence on angular velocity. Redundancies in the numerical solution were eliminated using multicollinearity diagnostic algorithms. The results revealed that the wrist joint was found to have constant stiffness and damping and no regulation of these coefficients was necessary during gait. Both in the elbow and shoulder joints stiffness included a constant coefficient as well as an angular velocity-dependent coefficient. Although all tested subjects demonstrated ability to prevent spillage of liquid, there was a considerable variability among the results obtained, indicating that the compensatory mechanisms employed by each subject to regulate the mechanical impedance were subjective. These results can help in the optimization of manual materials handeling tasks in industrial settings as well as future design of prosthetic arms, robotic appliances and man machine interfacing devices.

Constant and Variable Stiffness and Damping of the Leg Joints in Human Hopping

2003 ◽  
Vol 125 (4) ◽  
pp. 507-514 ◽  
Author(s):  
Svetlana Rapoport ◽  
Joseph Mizrahi ◽  
Eitan Kimmel ◽  
Oleg Verbitsky ◽  
Eli Isakov
Keyword(s):  
Sagittal Plane ◽  
Control Strategies ◽  
Joint Stiffness ◽  
Variable Stiffness ◽  
Initial Stiffness ◽  
Contact Phase ◽  
First Order ◽  
Order Dependence ◽  
Constant Stiffness ◽  
Stiffness And Damping

The present study deals with the stiffness and damping profiles of the leg joints during the ground-contact phase of hopping. A two-dimensional (sagittal plane) jumping model, consisting of four linked rigid segments and including the paired feet, shanks, thighs, and the head–arms–trunk segment, was developed. The segments were interconnected by damped torsional springs, representing the action of the muscles, tendons and ligaments across the joint and of the other joint tissues. A regressive function was used to express stiffness and damping, and included second-order dependence on angle and first-order dependence on angular velocity. By eliminating redundancies in the numerical solution using multicollinearity diagnostic algorithms, the model results revealed that the correct and sufficient nonlinearity for the joint stiffness is of the first order. Damping was found negligible. The stiffness profiles obtained were bell-shaped with a maximum near mid-stance and nonzero edge values. In predicting the joint moments, the obtained variable joint stiffnesses provided a closer agreement compared to a constant stiffness model. The maximal stiffness was found to be in linear correlation with the initial stiffness in each joint, providing support to the of muscles’ preactivation strategy during the flight phase of hopping. All stiffnesses increased with increasing hopping frequency. The model presented provides an effective tool for future designing of artificial legs and robots and for the development of more accurate control strategies.

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