Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Formulation of Boundary Conditions in Flow Systems

1994 ◽  
Vol 59 (2) ◽  
pp. 345-358
Author(s):  
Vladimír Kudrna ◽  
Pavel Hasal ◽  
Libor Vejmola
Keyword(s):  
Boundary Conditions ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Dispersion Model ◽  
Point Of View ◽  
General Point ◽  
Engineering Systems ◽  
Boundary Conditions For Diffusion ◽  
Flow Through ◽  
The One

Problems associated with the formulation of the boundary conditions for diffusion equations describing flow-through chemical-engineering systems from the point of view of stochastic process theory are discussed. An approach to modelling such systems is presented, allowing the one-dimensional diffusion (dispersion) model of a continuous flow mixer, commonly used in chemical engineering, to be reassessed from a rather general point of view.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Non-Isothermal Flow Chemical Reactor

1996 ◽  
Vol 61 (2) ◽  
pp. 242-258 ◽  
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Stochastic Model ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Dispersion Model ◽  
Chemical Reactor ◽  
Segregation Index ◽  
One Dimensional ◽  
A Value ◽  
Isothermal Case ◽  
Flow Through

Recently developed stochastic model of a one-dimensional flow-through chemical reactor is extended in this paper also to the non-isothermal case. The model enables the evaluation of concentration and temperature profiles along the reactor. The results are compared with the commonly used one-dimensional dispersion model with Danckwerts' boundary conditions. The stochastic model also enables to evaluate a value of the segregation index.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Isothermal Continuous Flow Chemical Reactor

1994 ◽  
Vol 59 (8) ◽  
pp. 1772-1787
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Continuous Flow ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Chemical Reactor ◽  
Point Of View ◽  
General Point ◽  
Stochastic Description ◽  
One Dimensional ◽  
Reactor Operating ◽  
Parameter Values

A model of an isothermal one-dimensional continuous flow chemical reactor operating at the steady state was derived using a stochastic description of motion of the reacting molecules. The model enables evaluation of the conversion of the reacting components. At the limiting parameter values the model yields results identical to those of the simplified models conventionally used in chemical reactor engineering. The model also enables the applicability of Danckwerts' boundary conditions to be assessed from a more general point of view.

scholarly journals The homogeneous catalysis of gaseous reactions by iodine. The decomposition of propionic aldehyde, and a general discussion

1933 ◽  
Vol 142 (846) ◽  
pp. 77-88 ◽  
Keyword(s):  
Kinetic Analysis ◽  
Homogeneous Catalysis ◽  
Chemical Change ◽  
Point Of View ◽  
The Other ◽  
Side Reactions ◽  
General Point ◽  
Chemical Changes ◽  
Secondary Reactions ◽  
The One

Previous papers have dealt with the homogeneous catalysis of the decomposition of ethers and of acetaldehyde by iodine. The problem of the mechanism of these catalysed reactions can be approached in two ways: on the one hand, by seeking to obtain as complete a picture as possible of the types of chemical change which are susceptible to the action of a given catalyst, and, the catalysts which will promote a given chemical change; and, on the other hand, by investigating in detail the kinetics and molecular statistics of individual reactions. Experiments on the different kinds of reaction which iodine will catalyse are being published elsewhere. Most of the chemical changes have involved too many side reactions, or secondary reactions with the catalyst, to be suitable for complete kinetic analysis. Nevertheless, they show the chemical specificity of the action of iodine in the clearest manner, and this aspect of the problem is discussed from a general point of view in the last section of the present paper.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Dynamic Stochastic Model of Flow Mixer

1994 ◽  
Vol 59 (7) ◽  
pp. 1551-1570
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Time Distribution ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Extreme Values ◽  
Stochastic Diffusion ◽  
One Dimensional ◽  
Simplifying Assumptions ◽  
Dynamic Stochastic ◽  
The Common ◽  
The One

The one-dimensional stochastic diffusion model of a continuous flow mixer is proposed incorporating (contrary to commonly used diffusion models) a distribution of velocities of diffusing particles. Simplifying assumptions enabled us to derive an analytical expression for the liquid residence time distribution and concentration profile inside the mixer. For extreme values of parameters, the model becomes identical with the common idealized models usually adopted in chemical engineering.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Relations between Different Types of Diffusion Equations

1992 ◽  
Vol 57 (6) ◽  
pp. 1248-1261 ◽  
Author(s):  
Vladimír Kudrna ◽  
Daniel Turzík
Keyword(s):  
Differential Equations ◽  
Diffusion Equation ◽  
Stochastic Differential Equations ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Point Of View ◽  
Diffusion Equations ◽  
Complex Diffusion ◽  
Different Types ◽  
Individual Particles

The dependence is discussed between the "clasical" diffusion equation commonly used in chemical engineering and the stochastic differential equations which describe this diffusion from the point of view of micromotion of individual particles. The resulting equations can be useful above all for the modelling of more complex diffusion processes.

Vernunftbegründung in der Ethik

1993 ◽  
Vol 37 (1) ◽  
pp. 22-32
Author(s):  
Christofer Frey
Keyword(s):  
Natural Law ◽  
Present Situation ◽  
Roman Catholic ◽  
Point Of View ◽  
The Other ◽  
General Point ◽  
A Posteriori ◽  
Moral Systems ◽  
The One ◽  
Ethical Systems

Abstract This contribution to a colloquy of Roman-catholic moral theologians and Protestant teachers of ethics challenges the simple juxtaposition of reasonable and biblical foundation of norms and moral systems. The hypothesis of this paper however, presupposes, that >foundation< implies more than a simple deduction from a general point of view or a formal (but a posteriori) Iegitimation of single norms by the principle of universalizability, but it includes transeendental considerations- concerning the problern of human freedom- and the regulating idea of a communion by consensus, integrated into basic perspectives ofconduct oflife. Biblical points ofview regulating ethical systems presuppose such perspectives. Appeals to reason in Protestant ethics transport questions and ideas of the natural-law-tradition even in systems which are deeply linked with a theology of revelation. If this analysis indicates correctly the present situation of Protestant ethics at least in Germany, the often assumed antagonism of a humanist and reason-oriented ethics on the one hand and a heteronomaus ethics relying on revelation on the other tends to be delusive.

Understanding functional illiteracy from a policy, adult education, and cognition point of view: Towards a joint referent framework

2019 ◽  
Vol 30 (2) ◽  
pp. 109-122
Author(s):  
Aleksandar Bulajić ◽  
Miomir Despotović ◽  
Thomas Lachmann
Keyword(s):  
Adult Education ◽  
Operational Definition ◽  
Literacy Skills ◽  
Point Of View ◽  
Industrialized Countries ◽  
Functional Illiteracy ◽  
Scale Levels ◽  
Components Of Reading ◽  
The One ◽  
Definition Of

Abstract. The article discusses the emergence of a functional literacy construct and the rediscovery of illiteracy in industrialized countries during the second half of the 20th century. It offers a short explanation of how the construct evolved over time. In addition, it explores how functional (il)literacy is conceived differently by research discourses of cognitive and neural studies, on the one hand, and by prescriptive and normative international policy documents and adult education, on the other hand. Furthermore, it analyses how literacy skills surveys such as the Level One Study (leo.) or the PIAAC may help to bridge the gap between cognitive and more practical and educational approaches to literacy, the goal being to place the functional illiteracy (FI) construct within its existing scale levels. It also sheds more light on the way in which FI can be perceived in terms of different cognitive processes and underlying components of reading. By building on the previous work of other authors and previous definitions, the article brings together different views of FI and offers a perspective for a needed operational definition of the concept, which would be an appropriate reference point for future educational, political, and scientific utilization.

Recommendations of The Ombudsman’s Dilemma: Between Law Enforcement Officials and Protection of Credibility

2018 ◽  
Vol 2 ◽  
pp. 1-12
Author(s):  
Dyah Adriantini Sintha Dewi
Keyword(s):  
Law Enforcement ◽  
Public Service ◽  
Public Services ◽  
Point Of View ◽  
Law Enforcement Officials ◽  
Muslim Majority ◽  
The Republic ◽  
The Government ◽  
The One ◽  
Oversight Body

The Ombudsman as an external oversight body for official performance, in Fikih Siyasah (constitutionality in Islam) is included in the supervision stipulated in legislation (al-musahabah al-qomariyah). Supervision is done so that public service delivery to the community is in accordance with the rights of the community. This is done because in carrying out its duties, officials are very likely to conduct mal administration, which is bad public services that cause harm to the community. The Ombudsman is an institution authorized to resolve the mal administration issue, in which one of its products is by issuing a recommendation. Although Law No. 37 of 2018 on the Ombudsman of the Republic of Indonesia states that the recommendation is mandatory, theombudsman's recommendations have not been implemented. This is due to differences in point of view, ie on the one hand in the context of law enforcement, but on the other hand the implementation of the recommendation is considered as a means of opening the disgrace of officials. Recommendations are the last alternative of Ombudsman's efforts to resolve the mal administration case, given that a win-win solution is the goal, then mediation becomes the main effort. This is in accordance with the condition of the Muslim majority of Indonesian nation and prioritizes deliberation in resolving dispute. Therefore, it is necessary to educate the community and officials related to the implementation of the Ombudsman's recommendations in order to provide good public services for the community, which is the obligation of the government.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

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