Miniaturization principle

Akay, G., Process Intensification and Miniaturization, Principles and Applications in Biological, Chemical and Environmental Technologies, Elsevier, New York, 2004. 

The basic principles of swimming-pool water treatment also apply to spas and hot tubs. However, spas and tubs are not miniature swimming pools but are unique in treatment requkements because of use patterns and a high ratio of bather to water. Eor example, four people in a 1.9-m (500-gal) spa or tub have a sanitizer demand equal to 160 people in a 75.7-m (20,000-gal) swimming pool. 

Rinard dedicated his research to a detailed analysis of methodological aspects of a micro-reactor plant concept which he also termed mini-plant production [85] (see also [4, 9, 10] for a commented, short description). Important criteria in this concept are JIT (Just-in-time) production, zero holdup, inherent safety, modularity and the KISS (keep it simple, stupid) principle. Based on this conceptual definition, Rinard describes different phases in plant development. Essential for his entire work is the pragmatic way of finding process solutions, truly of hybrid character ]149] (miniaturization only where really needed). Recent investigations are concerned with the scalability of hybrid micro-reactor plants and the limits thereof ]149], Expliddy he recommends jointly using micro- and meso-scale components. 

In the mid-IR, routine infrared spectroscopy nowadays almost exclusively uses Fourier-transform (FT) spectrometers. This principle is a standard method in modem analytical chemistry45. Although some efforts have been made to design ultra-compact FT-IR spectrometers for use under real-world conditions, standard systems are still too bulky for many applications. A new approach is the use of micro-fabrication techniques. As an example for this technology, a miniature single-pass Fourier transform spectrometer integrated on a 10 x 5 cm optical bench has been demonstrated to be feasible. Based upon a classical Michelson interferometer design, all... 

The FPI principle can also be used to develop thin-film-coating-based chemical sensors. For example, a thin layer of zeolite film has been coated to a cleaved endface of a single-mode fiber to form a low-finesse FPI sensor for chemical detection. Zeolite presents a group of crystalline aluminosilicate materials with uniform subnanometer or nanometer scale pores. Traditionally, porous zeolite materials have been used as adsorbents, catalysts, and molecular sieves for molecular or ionic separation, electrode modification, and selectivity enhancement for chemical sensors. Recently, it has been revealed that zeolites possess a unique combination of chemical and optical properties. When properly integrated with a photonic device, these unique properties may be fully utilized to develop miniaturized optical chemical sensors with high sensitivity and potentially high selectivity for various in situ monitoring applications. 

Miniaturizing the column i.d. is of great benefit to the sensitivity of ESl-MS, which behaves as a concentration-sensitive detection principle, because the concentration of equally abundant components in the LC mobile phase is proportional to the square of the column internal diameter. Column diameters from 150 to 15 jm with flow rates 20-200nL improve detection limits of peptides 1-2 orders magnitude over microliter flow rates. Several references referred to in other sections of this chapter discuss the use of LC-ESI MS to characterize separation products. and a sample chromatogram from Ito and coworkers. is seen in Figure 3.8. Table 3.4 provides additional and references that have used this technique. 

Since the development of HPLC as a separation technique, considerable effort has been spent on the design and improvement of suitable detectors. The detector is perhaps the second-most important component of an HPLC system, after the column that performs the actual separation it would be pointless to perform any separation without some means of identifying the separated components. To this end, a number of analytical techniques have been employed to examine either samples taken from a fraction collector or the column effluent itself. Although many different physical principles have been examined for their potential as chromatography detectors, only four main types of detectors have obtained almost universal application, namely, ultraviolet (UV) absorbance, refractive index (RI), fluorescence, and conductivity detectors. Today, these detectors are used in about 80% of all separations. Newer varieties of detector such as the laser-induced fluorescence (LIE), electrochemical (EC), evaporative light scattering (ELS), and mass spectrometer (MS) detectors have been developed to meet the demands set by either specialized analyses or by miniaturization. 

Miniaturization—chemistry and biology on a chip—has resulted only because of the confluence of science and engineering. The development of micro-fluidics technology has mainly been driven by the need to miniaturize, integrate, and automate biochemical analysis to increase speed and reduce costs. We are experiencing a revolution in the miniaturization of chemical systems for detection and analysis of hosts of chemical and biological materials and agents. Applications of basic principles of electrokinetics, hydraulics, and surface science have... 

Reducing each component would, in principle, create a miniaturized instrument or device, but in most cases, this simple idea probably would not work. Quantum mechanics becomes important at the scale of nanotechnology, and as described in the sidebar on page 20-21, its laws are different from Newtonian physics. 

Another sensor system that further expands the capabilities of the Chronotox is the Personal Tape Sampler (PTS). The PTS (Figure 5) is a miniaturized gas monitor designed primarily to be worn by a worker during his entire workshift. It operates on the principle of specific chemical colorimetric reactions occurring on a dry chemically impregnated paper tape and gives... 

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