Wyniki wyszukiwania - Biblioteka Nauki

1

Kinetic analysis of the transient phase and steady state of open multicyclic enzyme cascades

100%

Varón R. , Havsteen B. H. , Valero E. , Molina-Alarcón M. , García-Cánovas F. , García-Moreno M.

Acta Biochimica Polonica

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2005

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tom 52

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nr 4

765-780

EN

This paper presents a kinetic analysis of the whole reaction course, i.e. of both the transient phase and the steady state, of open multicyclic enzyme cascade systems. Equations for fractional modifications are obtained which are valid for the whole reaction course. The steady state expressions for the fractional modifications were derived from the latter equations since they are not restricted to the condition of rapid equilibrium. Finally, the validity of our results is discussed and tested by numerical integration. Apart from the intrinsic value of knowing the kinetic behaviour of any of the species involved in any open multicyclic enzyme cascade, the kinetic analysis presented here can be the basis of future contributions concerning open multicyclic enzyme cascades which require the knowledge of their time course equations (e.g. evaluation of the time needed to reach the steady state, suggestion of kinetic data analysis, etc.), analogous to those already carried out for open bicyclic cascades.

2

Kinetic analysis of the transient phase and steady state of open multicyclic enzyme cascades

72%

Varon R. , Havsteen B. H. , Valero E. , Molina-Alarcon M. , Garcia-Canovas F. , Garcia-Moreno M.

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2005

|

tom 52

|

nr 4

EN

This paper presents a kinetic analysis of the whole reaction course, i.e. of both the transient phase and the steady state, of open multicyclic enzyme cascade systems. Equations for fractional modifications are obtained which are valid for the whole reaction course. The steady state expressions for the fractional modifications were derived from the latter equations since they are not restricted to the condition of rapid equilibrium. Finally, the validity of our results is discussed and tested by numerical integration. Apart from the intrinsic value of knowing the kinetic behaviour of any of the species involved in any open multicyclic enzyme cascade, the kinetic analysis presented here can be the basis of future contributions concerning open multicyclic enzyme cascades which require the knowledge of their time course equations (e.g. evaluation of the time needed to reach the steady state, suggestion of kinetic data analysis, etc.), analogous to those already carried out for open bicyclic cascades.

3

Influence of titanium powder characteristics and heating rate on the liquid phase sintering of Fe8%Ti powder compacts.

51%

Ciaś A. , Stoytchev M.

Inżynieria Materiałowa

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1998

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tom R. XIX, nr 4

1131-1136

EN

In view of interest in the use of titanium as an alloying element to the sintering of iron-based powder compacts, an examination has been made of the influence of the characteristics of the titanium powder and heating rate on sintering process. Transient liquid phase sintering was examined for Fe8%Ti powder mixtures. The effect of additions of narrow sized fractions of titanium powder and heating rate on the dimensional changes obtained on sintering Fe8%Ti compacts made with Hoganas NC 100.24 sponge iron and 7, 16, 56 and 200 micrometres titanium powders has been determined. The experimental plan included the effects of several processing variable, such as titanium paricle size, heating rate, sintering temperature and sintering time.Two types of experiments were used to study sintering. The effects has been examined in relation to the sintering mechanism by dilatometry, using a comuterised precision vacuum dilatometer Netzsch 402S with an extended range, constant load single pushrod. In addition to dilatometer experiments, batch sintering was conducted in a vacuum furnace. It was found that the use of fine titanium powder and controlled heating rate reduced the dimensional change.