A feedback reactor with continuous injection of one reaction component using spectrophotometric indication I

1988 ◽  
Vol 53 (5) ◽  
pp. 929-938
Author(s):  
František Skopal
Keyword(s):  
Time Dependence ◽  
Rate Constants ◽  
The Other ◽  
Experimental Apparatus ◽  
Set Up ◽  
Continuous Injection ◽  
Reaction Component

The time dependence of the volume of solution of one reaction component injected continuously to the solution of the other reaction component is derived for the case that the injection is controlled by feedback to hold the absorbance of the reaction mixture constant. An experimental apparatus based on this principle has been set up and its function tested on two 2nd order reactions, whereby the theoretical relations derived for the determination of the rate constants have also been verified.

Feedback Reactor with Continuous Injection of One Reaction Component with Potentiometric Indication

1992 ◽  
Vol 57 (7) ◽  
pp. 1385-1392
Author(s):  
František Skopal
Keyword(s):  
Time Dependence ◽  
Second Order ◽  
The Other ◽  
Potential Constant ◽  
Continuous Injection ◽  
Reaction Component ◽  
Reactant Solution

The time dependence of the volume of one reactant solution injected into the other was derived. The injection is feedback-controlled to hold the reaction mixture potential constant. The theoretical relations were tested in a feedback reactor on two second-order reactions.

A feedback reactor for discontinuous feed of a reaction component with spectrophotometric indication

1985 ◽  
Vol 50 (5) ◽  
pp. 1022-1032
Author(s):  
František Skopal
Keyword(s):  
Time Dependence ◽  
Rate Constant ◽  
The Other ◽  
Irreversible Reaction ◽  
Reaction Component

The absorbance-time dependence has been derived for a repeated arbitrary feed of one reaction component into solution of the other component controlled by the feedback. On the basis of the expressions derived, methods have been suggested for determination of the rate constant of irreversible reaction of the IInd order, and they have been experimentaly tested on two reactions.

Determination of Stresses in Cemented Lap Joints

1953 ◽  
Vol 20 (3) ◽  
pp. 355-364
Author(s):  
R. W. Cornell
Keyword(s):  
Differential Equations ◽  
Infinite Number ◽  
Lap Joints ◽  
The Other ◽  
Complete Analysis ◽  
Stress Distributions ◽  
Lap Joint ◽  
Analogy Method ◽  
Set Up

Abstract A variation and extension of Goland and Reissner’s (1) method of approach is presented for determining the stresses in cemented lap joints by assuming that the two lap-joint plates act like simple beams and the more elastic cement layer is an infinite number of shear and tension springs. Differential equations are set up which describe the transfer of the load in one beam through the springs to the other beam. From the solution of these differential equations a fairly complete analysis of the stresses in the lap joint is obtained. The spring-beam analogy method is applied to a particular type of lap joint, and an analysis of the stresses at the discontinuity, stress distributions, and the effects of variables on these stresses are presented. In order to check the analytical results, they are compared to photoelastic and brittle lacquer experimental results. The spring-beam analogy solution was found to give a fairly accurate presentation of the stresses in the lap joint investigated and should be useful in analyzing other cemented lap-joint structures.

Cefoxitin interferes with the "Clini-Skreen" column method for urinary 17-hydroxycorticosteroids.

1987 ◽  
Vol 33 (7) ◽  
pp. 1219-1222
Author(s):  
M H Kroll ◽  
A J Jackson ◽  
R J Elin
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Molar Absorptivity ◽  
The Other ◽  
Absorbance Maximum ◽  
Column Method ◽  
Apparent Concentration

Abstract Cefoxitin interferes with determination of urinary 17-hydroxycorticosteroids. The apparent concentration of hormone is increased from three- to 10-fold in samples from patients receiving cefoxitin when the Amberlite XAD-2 "Clini-Skreen" column is used. To determine the mechanism of interference, we reacted aqueous solutions of cefoxitin, cortisol, cortisone, and 11-deoxycortisol with phenylhydrazine; recorded the adsorption spectra; and determined the molar absorptivities and the equilibrium and rate constants. Also, we recorded the absorption spectra of phenylhydrazine with eight other cepha antibiotics and benzylpenicillin. Cortisol, cortisone, 11-deoxycortisol, and cefoxitin react with phenylhydrazine and absorb light with superimposable spectra and absorption maxima of 410 nm. The other antibiotics react with phenylhydrazine but absorbance maxima of the products vary, none being at 410 nm. Cortisol, cortisone, and 11-deoxycortisol react with phenylhydrazine 35-fold faster, have equilibrium constants ninefold greater, and have molar absorptivities 1.6 times that of cefoxitin. Thus, cefoxitin interferes with determination of urinary 17-hydroxycorticosteroids by forming a chromophore with the same absorbance maximum and with a molar absorptivity similar to cortisol, but much more slowly.

scholarly journals Flame speeds in the “inflammation” and “detonation” of moist carbonic oxide-oxygen mixtures

1931 ◽  
Vol 130 (814) ◽  
pp. 542-551
Keyword(s):  
Initial Phase ◽  
Horizontal Tube ◽  
Complete Data ◽  
The Other ◽  
Explosive Mixture ◽  
Explosion Limits ◽  
Oscillatory Movement ◽  
Set Up

Seeing that hitherto our knowledge of the flame speeds involved in the “inflammation” and “detonation” of carbonic oxide-oxygen mixtures has been mainly confined to those of the theoretical 2CO+O 2 mixture, and that complete data over the whole “explosion range” are needed for the determination of questions relating to the combustion of carbonic oxide, we have lately carried out experiments with a view to suppyling the deficiency; and this paper embodies the results thereof. Experimental. A.-Flame Speeds in the Initial Phase of "Inflammation." It may be recalled that when a quiescent explosive mixture is ignited at the open end of a horizontal tube, the other end being closed, a slow and usually uniform flame movement is initially set up. Except in mixtures very near to one or other of the explosion limits, this initial phase is soon succeeded by an oscillatory movement during which the flame swings backwards and forwards, usually with increasing amplitude, until it is either extinguished, by swinging too far backwards into its own products of combustion, or gives rise to a must accelerated movement, may be ending up in "detonation" if sufficiently accelerated during a forward swing.

scholarly journals Automation and Software of the Wanschaff Vertical Circle at Goloseevo

1986 ◽  
Vol 109 ◽  
pp. 463-464
Author(s):  
A.S. Kharin ◽  
L.A. Kukharskij ◽  
P.F. Lazorenko ◽  
N.F. Minyajlo ◽  
M.L. Tsesis
Keyword(s):  
Vertical Axis ◽  
Automatic Machine ◽  
The Other ◽  
Vertical Circle ◽  
Other Information ◽  
Set Up

The Wanschaff vertical circle, set up at Goloseevo in 1949 was built in 1914. The instrument was originally equiped with four visual microscopes for reading the circle, with a visual eyepiece micrometer, and with two levels for the determination of the inclination of the vertical axis. After the instrument had been installed in a new pavilion in 1972, the visual microscopes were replaced by photographic devices, and a semi-automatic machine for measuring the circle readings with output on punched tape was developed. In 1973,the eyepiece micrometer was equiped with a precision potentiometer of the type which together with an automatic voltmeter of the type the digitizer micrometer readings punches them on tape. The other information is punched on cards by the operator at the data desk.

The Determination of the Expansion Forces in Piping by Model Test

1939 ◽  
Vol 6 (1) ◽  
pp. A21-A24
Author(s):  
Harold W. Semar
Keyword(s):  
Steam Turbine ◽  
Model Test ◽  
The Other ◽  
Inlet Pipe ◽  
Full Size ◽  
Pipe Expansion ◽  
Measured Amount ◽  
Set Up

Abstract The paper describes apparatus for testing models of piping installations to determine the forces set up in the full-size installation due to expansion. The method consists in fixing one end of the model in a slide which can be moved a measured amount, and measuring the forces at the other end by means of a fixture which holds that end rigidly in place and permits measurement of six forces in three coordinate planes, which are the equivalent of forces in coordinate directions plus moments in coordinate planes. The slide of the movable end is placed so that its direction of motion coincides with the direction of the pipe expansion. A complete example is given showing the steps in determining the end reactions of an inlet pipe for a steam turbine.

Synthesis of N-hydroxymethylacrylamide in an aqueous solution

1986 ◽  
Vol 51 (8) ◽  
pp. 1656-1664 ◽  
Author(s):  
Alois Matějíček ◽  
Jaroslav Černý
Keyword(s):  
Aqueous Solution ◽  
Time Dependence ◽  
Equilibrium Constant ◽  
Rate Constants ◽  
Empirical Relation ◽  
Methanol Concentration ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Constant Molar Ratio

The paper deals with a reaction between acrylamide and formaldehyde leading to the synthesis of N-hydroxymethylacrylamide. The reaction was carried out in the temperature range 303.2 to 333.2 K, pH 9.2-10.35, at the methanol concentration 0-6.5239 mol l-1 at the constant molar ratio of acrylamide to formaldehyde 1 : 1. The time dependence of the loss of formaldehyde in the reaction mixture was approximated by an empirical relation (cF)0 - cF = t/(A + Bt), which was used in the determination of the rate constants for a reaction leading to the synthesis of N-hydroxymethylacrylamide and for the reversible reaction, and of the equilibrium constant of the reaction. The measurements and calculations showed that the optimal conditions for the synthesis of N-hydroxymethylacrylamide were 313.2 K, methanol concentration 1.5 mol l-1 and pH 9.8-10.1.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

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