13 Electrochemistry in Laboratory Flow Systems

Organic electrosynthesis in flow reactors is an area of increasing interest, with efficient mass transport and high electrode area to reactor volume present in many flow electrolysis cell designs facilitating higher rates of production with high selectivity. The controlled reaction environment available in flow cells also offers opportunities to develop new electrochemical processes. In this chapter, various types of electrochemical flow cells are reviewed in the context of laboratory synthesis, paying particular attention to how the different reactor environments impact upon the electrochemical processes, and the factors responsible for good cell performance. Coverage includes well-established plane-parallel-plate designs, reactors with small interelectrode gaps, extended-channel electrolysis cells, and highly sophisticated designs with rapidly rotating electrodes to enhance mass transport. In each case, illustrative electrosyntheses are presented.

Comparison of Two Approaches to Calculate Orthoscopic Interference Pictures

In this article a computer model of the polariscope is regarded as a 3D scene. In this case, the interference pictures are the result of rendering. The light rays pass through several well-specified polariscope blocks. When developing a suitable renderer, algorithms are selected and estimated for calculating the behavior of the beams based on their physical correctness, speed, etc. A plane parallel plate of an anisotropic crystal is the main block of the scene that affects the resulting image. This article discusses the calculation of the interaction of light with this plate only. Two approaches to calculate orthoscopic interference pictures of optically anisotropic transparent crystals are considered. One is described in many well-known books and bases on definite simplifications. The other is a direct physically based modeling of a light ray path through a plane parallel plate made of a uniaxial crystal taking into account all losses of intensity while passing boundaries between media. The purpose of this paper is to estimate a difference between values obtained via different approaches

Calculation of the intrinsic thermal radiation of plane-parallel quasi-anisotropic multilayer plates with smooth boundaries

The physical meaning of new algorithms for calculating the intensity of a plane homogeneous monochromatic wave of electromagnetic radiation after passing through a multilayer quasi-anisotropic plane-parallel plate is discussed, taking into account the thermal radiation of the layers. The formula connecting the brightness temperature obtained by a microwave radiometer and the effective temperature of the observed surface is used in remote sensing of the earth's surface [16].In this paper, we develop a mathematical apparatus that allows one to construct algorithms that generalize this formula to an arbitrary number of homogeneous quasi-anisotropic layers of a plane-parallel plate. The solution of the problem is complicated by the need to take into account coherent and incoherent effects in a multilayer plate, as well as by the need to construct an adequate method for identifying the waves and energy fluxes under consideration, by the need to clarify the concept of an ideal radiometer that records the observed microwave radiation. In order to test new algorithms and obtain the first results, the facts obtained earlier [19] by calculating the reflection and transmission coefficients for free ice sheets are reproduced using new algorithms for calculating intensities. For an isotropic ice plate 50 cm thick in the L-range, there is a "transparency window" in the area of observation angles of 30 degrees for both polarizations simultaneously. The influence of ice anisotropy on the effects of bleaching and anti-bleaching and related to the Brewster angle is considered. Additionally, the contribution of the ice's own radiation to the observed brightness temperature was estimated by new methods. The case of an anisotropic ice plate with the same parameters but floating in water is considered. It is shown that a change in the conditions of reflection at the ice-substrate interface can be partially compensated by a change in the ice thickness. To control and evaluate the theoretically possible accumulation of errors in calculations, physical quantities are discussed that are analogous to the components of the Poyting vector and remain constant at the boundaries of the layers. For the considered cases of ice, these values are conserved with high accuracy.

MICROSCANNER ON THE BASIS OF THE SYNCHRONOUS MOTOR WITH AN EXTERNAL ROTOR FOR THERMAL IMAGING SYSTEMS AND THE TECHNIQUE OF ITS TUNING

The results of the development of microscanning devices for third-generation thermal imagers based on an external rotor engine are presented. The component that displaces the image of the scene is made of a germanium plane-parallel plate. Method for the device adjustment is presented.