The Consequences for Differential Thermal a N a L Y S I S of Assuming a Reaction to Be First-order
نویسنده
چکیده
AKt;TRACT From their isothermal experiments, Murray and White drew the conclusion that the dehydration reaOions of clays are first-order with a rate factor of Arrhenius form. The object of this paper is to discuss whether differential thermal analysis can be used to confirm or refute this hypothesis. The problem, previously considered by Murray and White, of a sample heated at a constant rate throughout is recalled. Particular attention is drawn to the effect of heating rate on the temperature at which the maximum rate of reaction occurs. To apply to differential thermal analysis, the treatment must be extended to take account of thermal gradients; as the mathematics involved is cumbersome, only results are considered. The most important result concerns the effects of sample size and dilution on the position of the turning-point. A disagreement with the results of experiments on kaolinite is pointed out; it is argued that only a small part of this disagreement is due to simplifications made in developing the theory, and it is concluded that the hypothesis that the clay reactions are first-order, with a rate factor of Arrhenius form, is only approximate.
منابع مشابه
Amitraz Poisoning; A case study
A m i t r a z, a n i ns e c t i c i d e /a ca ri c i de of the f o r m a m i d i n e p e st i c i d e s group, is a ? 2 a d r e n e r g i c ag on i st a nd of t he a m i d i ne c h e m i ca l f a m il y generally us e d to c o n t r ol animal e c top a r a s i t e s. Poisoning due to am i t r a z i s r a r e and character...
متن کاملRecurrent metrics in the geometry of second order differential equations
Given a pair (semispray $S$, metric $g$) on a tangent bundle, the family of nonlinear connections $N$ such that $g$ is recurrent with respect to $(S, N)$ with a fixed recurrent factor is determined by using the Obata tensors. In particular, we obtain a characterization for a pair $(N, g)$ to be recurrent as well as for the triple $(S, stackrel{c}{N}, g)$ where $stackrel{c}{N}$ is the canonical ...
متن کاملEffects of Thermal Diffusion and Radiation on Magnetohydrodynamic (MHD) Chemically Reacting Fluid Flow Past a Vertical Plate in a Slip Flow Regime
An analysis has been conceded to study the effects of Soret and thermal radiation effects on the magnetohydrodynamic convective flow of a viscous, incompressible, electrically conducting fluid with heat and mass transfer over a plate with time-dependent suction velocity in a slip flow regime in the presence of first-order chemical reaction. The slip conditions at the boundaries for the governin...
متن کاملExact Solution for Electrothermoelastic Behaviors of a Radially Polarized FGPM Rotating Disk
This article presents an exact solution for an axisymmetric functionally graded piezoelectric (FGP) rotating disk with constant thickness subjected to an electric field and thermal gradient. All mechanical, thermal and piezoelectric properties except for Poisson’s ratio are taken in the form of power functions in radial direction. After solving the heat transfer equation, first a symmetric dist...
متن کاملمحاسبه سطح مقطع دیفرانسیلی و کل تهییج تک الکترونی هلیوم در برخورد با پروتون در انرژیهای میانی و بالا به روش فرمولبندی سه جسمی
A three-body model is devised to study differential and total cross sections for the excitation of helium atom under impact of energetic protons. The actual process is a four body one but in the present model the process is simplified into a three-body one. In this model, an electron of helium atom is assumed to be inactive and only one electron of the atom is active. Therefore, the active ele...
متن کامل