scholarly journals Simulation of the dynamics of nitrogen metabolism in sheep

1976 ◽  
Vol 35 (1) ◽  
pp. 149-174 ◽  
Author(s):  
A. Mazanov ◽  
J. V. Nolan
Keyword(s):  
Mathematical Model ◽  
Nitrogen Metabolism ◽  
Transport Processes ◽  
Simulation Studies ◽  
Tracer Studies ◽  
First Order ◽  
Isotope Tracer ◽  
First Order Kinetics ◽  
Pool Model ◽  
N Metabolism

1. The results of isotope tracer studies of the dynamics of nitrogen metabolism in mature sheep were used to construct a seven-pool mathematical model.2. The model was extended to a nine-pool model, which incorporates lags describing the time taken for the passage of digesta through the gut of sheep.3. Simulation studies using these models satisfactorily predicted results of independent experiments.4. The dynamics of N metabolism in sheep appear to be best approximated by first-order kinetics; that is, many of the important N transport processes are substantially linear or concentration-dependent.

Estimation of Dispersion Number in Waste Stabilization Ponds

1999 ◽  
Vol 40 (7) ◽  
pp. 41-46 ◽  
Author(s):  
Ismail I. Esen ◽  
Yousif Al-Shayji
Keyword(s):  
Chemical Reactor ◽  
Simultaneous Estimation ◽  
Tracer Studies ◽  
Waste Stabilization Ponds ◽  
First Order ◽  
First Order Kinetics ◽  
Stabilization Ponds ◽  
Ideal Mixing ◽  
Waste Stabilization ◽  
Dispersion Number

The hydraulic behavior of waste stabilization ponds is rather complex, and the flow in ponds can at best be described as dispersed flow. The dispersion characteristics of existing ponds can be determined by tracer studies, but it is impractical to perform tracer studies under every possible hydraulic condition. On the other hand, in the assessment of pond performance, first-order kinetics for BOD removal and bacterial die-off have been generally adopted. In this study, a nonlinear least-squares scheme will be presented for the simultaneous estimation of the decay constant and the dispersion number from the well known Wehner-Wilhelm equation which describes the reduction in pollutant concentration in a chemical reactor exhibiting first-order kinetics and non-ideal mixing conditions. As an example, the procedure developed will be applied to actual BOD data obtained from model facultative ponds in Kuwait.

Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen
Keyword(s):  
Degradation Rate ◽  
Southern China ◽  
Catalytic Degradation ◽  
Pulp And Paper ◽  
Gaseous Pollutants ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

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