Thermal Kinetic Effects Research Articles

Determination of running temperature in entrained flow gasifier in regard to coal ash melting thermal kinetic effects

The operating temperature of entrained flow gasifier is one of the important parameters to determine its gasification efficiency, which is empirically estimated by ash fusion temperatures (AFTs) in the industry. However, the measurements of AFTs in labs are conducted at a very low heating rate (5–10 °C/min) compared to industrial entrained flow gasifiers (several hundred °C/s). The melting behaviors of coal ash under such huge varied conditions are different due to thermo-kinetic effects. Here, the factors concerning coal ash melting thermo-kinetics including heating rate, particle size, and retention time are explored by AFTs analyzer, thermal mechanical analysis, in-situ hot stage microscope and differential scanning calorimetry. The results of the investigation demonstrated that ash particle size and retention time showed limited influence on ash fusion behavior, while the influence of heating rates can not be ignored. Furthermore, an Arrhenian-based regression model covering major thermo-kinetics was developed to quantitatively predict the running temperature. The developed model suggested using the temperature that shrinkage corresponds to 75% to extrapolate the running temperature. The model can help to determine the operating temperature of slagging gasifiers.

Nonlinear scattering of Alfvén waves off low-frequency dust modes in a magnetized dusty plasma

The three-wave nonlinear scattering of an electromagnetic Alfven wave off a low-frequency dust mode,viz. dust-Bernstein mode in a homogeneous, magnetized, hot and collisionless dusty plasma, has been analytically investigated. The Vlasov equation in terms of gyrokinetic variables has been employed to find the nonlinear response of the plasma particles including the finite-Larmor-radius thermal kinetic effects. An approximate expression for the comparative growth rates of the three-wave parametric instability has been obtained. It is noted that for the usual dusty plasma parameters the parametric scattering of the electromagnetic Alfven waves through the dust-Bernstein modes in the low-density limit is more efficient than that in the high-density limit.

Ultra-Low-Frequency Electrostatic Modes in a MagnetizedDusty Plasma

A study on the extremely low-frequency possible electrostatic modesin a finite temperature magnetized dusty plasma taking the chargeddust grains as the third component has been carried out using theappropriate Vlasov-kinetic theory for the dynamics of the electrons,ions and the dust particles. It is found that the inequalities ofcharge and number density of plasma species, and thefinite-Larmor-radius thermal kinetic effects of the mobile chargeddust grains, introduce the existence of very low-frequencyelectrostatic eigenmodes in the three-component homogeneous magnetizeddusty plasma. The relevance of the present investigation to space andastrophysical situations as well as laboratory experiments for dustCoulomb crystallization has been pointed out.

Low-frequency electrostatic waves in a hot magnetized dusty plasma.

A gyrokinetic study of low-frequency---lower than the dust cyclotron frequency---electrostatic modes in a magnetized dusty plasma has been presented. It is found that the inequalities of charge and number densities of electrons, ions, and dust particles, and the finite-Larmor-radius thermal kinetic effects of the mobile charged dust grains, introduce the existence of low-frequency electrostatic eigenmodes in a three-component hot magnetized dusty plasma. The relevance of our investigation to space and astrophysical as well as laboratory experiments for dust-particulate attraction is pointed out.

Temperature effects on enzymes from homeothermic and heterothermic tissues of the harbor seal ( Phoca vitulina)

1. 1. Lactate dehydrogenase and pyruvate kinase of arterial smooth muscle of the harbor seal ( Phoca vitulina) exhibit thermal-kinetic properties similar to those observed for enzymes of poikilotherms. Enzyme-substrate affinity is inversely proportional to temperature over the range of temperatures the heterothermic flipper tissues experience. Consequently, the temperature coefficients of the enzymatic reactions are greatly reduced at physiological substrate concentrations. 2. 2. Kinetic comparisons of enzymes from homeothermic and heterothermic arteries revealed no differences in isoenzyme composition. 3. 3. Major differences in thermal-kinetic effects were found between seal arterial pyruvate kinase and rat skeletal muscle pyruvate kinase.