It has been proved mathematically that there exists an identity between the various published methods for determining the hold-up times in gas chromatography. All of these methods are based on the equation: ln t'(R) = ln (t(R) - t(M)) = a + bZ, where t(R), t'(R), and t(M) are retention times, adjusted retention times, and hold-up times, respectively; a and b are coefficients that depend on the ...

This paper proposes a new perspective in the enhancement of the closed-loop tracking performance by using the first-order hold (FOH) sensing technique. Firstly, the literature review and fundamentals of the FOH are outlined. Secondly, the performance of the most commonly used zero-order hold (ZOH) and that of the FOH are compared. Lastly, the detailed implementation of the FOH on a pendulum tra...

A method of calculating the second dimension hold-up time for comprehensive two-dimensional gas chromatographic (GC×GC) data was developed by incorporating the temperature information of the second dimension column into the calculation model. The model was developed by investigating the relationship between the coefficients in each of six literature reported nonlinear models and the relationshi...

the performance of a forced-liquid vertical tubular loop bioreactor (vtlb), a forced-liquid horizontal tubular loop bioreactor (htlb) and a gas-induced external airlift loop bioreactor (ealb) were compared for production of biomass from natural gas. hydrodynamic characteristics and mass transfer coefficients were determined as functions of design parameters, physical properties of gases as well...