FT-IR Spectroscopy of Thin Biological Layers

The use of FT-IR spectroscopy as a non-destructive, structure specific technique in the study of thin biological layers is described in this thesis

Optimum IR measurement conditions for thin layers on dielectric surfaces

The importance of signal-to-noise ratio (SNR) calculations for an optimum Fourier transform-infrared spectroscopy (FT-IR) detection of thin, isotropic layers on dielectric substrates is discussed; some illustrative examples are given. It is found that the SNR increases with increasing refractive index of the substrate whereas the use of p-polarized light is preferable. Optimum measurement conditions for oriented layers were found for a Ge substrate at an angle of incidence of 50–55°

Light-induced two-dimensional FT-IR spectroscopy of BacterioRhodopsin

Two-dimensional Fourier transform infrared (2D FT-IR) spectroscopy was applied to study the slower states of the membrane protein bacterioRhodopsin (bR) photocycle, with bR adsorbed on a ZnSe attenuated total reflectance (ATR) crystal. The M and the N states of the bR photocycle could be discriminated, and 2D spectra revealed an N state absorption band at 1536 cm−1 that is normally covered by the broader and bigger 1527 cm−1 M state absorption band. 2D FT-IR absorbance changes are presented in a more convenient way for analysis than in traditional 2D FT-IR spectroscopy by using 2D-phase spectra and phase/amplitude calculations

Reactor operating procedures for start up of continuously operated chemical plants

Rules are presented for the startup of an adiabatic tubular reactor, based on a qualitative analysis of the dynamic behavior of continuously-operated vapor- and liquid-phase processes. The relationships between the process dynamics, operating criteria, and operating constraints are investigated, since a reactor startup cannot be isolated from an entire plant startup. Composition control of the process material is critical to speed up plant startup operations and to minimize the amount of offgrade materials. The initial reactor conditions are normally critical for a successful startup. For process conditioning, a plant should have an operating mode at which the reactor can be included in a recycle loop together with its feed system and downstream process section. Experimental data of an adiabatic tubular reactor startup and thermal runaway demonstrate some operational problems when such an intermediate operating stage is missing. The derived rules are applied to an industrial, highly heat-integrated reactor section, and the resulting startup strategy is summarized in an elementary-step diagram