Multi-component technology

In the field of multi-component technology, considerable progress has been made over the past decade [36 to 41 ] which can be seen in the variety of available methods and mold designs (Figure 1.66). 

Good adhesion compatibility is important in most multi-component technologies. This is obtained due to close chemical similarity. Non-adhesion is needed for movable doll limbs or venting grilles for car interiors. 

FIGURE 2.1 Example of a mold for the multi-component technology and the back injection technology... 

Multilayer coatings of different composition and thickness are widely used in materials science and in the production of high-technology materials. The single- or multi-component thin layers significantly improve important characteristics of the materials with, e.g., specific properties. 

Yu, A.B. and Standish, N., 1987. Porosity calculations of multi-component mixtures of spherical particles. Powder Technology, 52, 233-241. 

Richter, T., Ehrfeld, W., Hessel, V., Lowe, H., Storz, M., Wolf, A., A flexible multi component microreaction system for liquid phase reactions, in Ehrfeld, W. (Ed.), Microreaction Technology 3rd International Conference on Microreaction Technology, Proc. of IMRET 3,... 

The application of microwave technology to speed up chemical reactions is now an accepted and acknowledged tool among chemists. However, combining it with other methodologies such as multi-component reactions can further enhance the benefits offered by the microwaves alone. 

This chapter is a non-comprehensive summary of the available papers where microwave dielectric heating has been used in combination with multi-component reactions. The examples highlight the fabulous possibilities that can be found in the cross-section of these technologies. The numbers of papers describing the combination are still limited, but nevertheless microwave heating will have an impact in the area and most certainly, we will see an increased number of publications and increased interest in the near future. 

In process analytics, chemometrics can undergo a staling process during the early phases of implementation, the benefits of the technology are most apparent (e.g. interference rejection, multi-component analysis capabilities, and fault monitoring), but over time, as conditions change and new interferences appear, the models can lose their accuracy. This can lead to suspicions of bait and switch. ... 

Hornsby, P.R., Ahmadnia, A., Marosi, G., and Anna, P., Tailoring the fire retardant performance of polymers using multi-component processing technologies, Proceedings from Society of Plastics Engineers Annual Technical Conference (ANTEC 03), Nashville, TN, May 5-8, 2003. 

Initially, the interest was on the oxidation of model substances or, in any case, of substances whose oxidation was already studied by other technologies, the results of which could be used for comparison. Phenol and oxalic acid were often considered to model the behaviour of the aromatic and aliphatic fractions of the waste, respectively. Single component artificial solutions were firstly considered. Then, attention was focused also to different substances, such as substituted phenols, or more complex molecules such as those of dyes. Moreover, an increasing number of papers dealt with the treatment of real wastes but in any case, at the moment, the study is performed on a laboratory scale or, in a few cases, on a pilot scale. Some studies reported the treatment of multi-component solutions which better simulate the real composition of the waste, at least concerning some peculiar characteristics of it. This is the case, e.g., of works on oxidation of dyes in which chlorides were added to the model solutions. 

After evaluation of the technological parameters and in vitro release behavior of the tablets, no sharp percolation thresholds were found in these ternary systems for the employed components separately. Nevertheless, a combined percolation threshold of the hydrophilic components was found, demonstrating that a multi-component system can be reduced to a binary one using a discriminating property [39]. 

It is well-known that the nature of NG composition has a negative impact on ANG technology due to the deterioration of the adsorbent capacity on extended cyclic operation. Although this problem has been addressed by some authors, either experimentally or theoretically, the single- and multi-component adsorption data reported to date, as they apply to natural gas, are still rather scarce. 

W.J.W. Bakker, G. Zheng, M. Makkee, F. Kapteijn, J.A. Moulijn, E.R. Geus, and H. van Bekkum, Single- and Multi-component transport through metal-supported MR zeolite membranes, in Precision Process Technology (M.P.C. Weijnen and A.A.H. Drinkenbuig, eds.), Kluwer Academic Publishers, Amsterdam, 1993, p. 425. 

The solubilities of gases, liquids, and solids in multi-component solvents constitute important issues in science and technology. The aqueous multicomponent solutions represent a meaningful example because the overwhelming majority of solutions of biological and environmental interest are aqueous multicomponent solutions. 

Sievers, W. and Mersmann, A. Single and multi-component adsorption equilibria of C02, N2, CO, and CH4 in hydrogen purification process. Chemical Engineering Technology, 1997, 17, 325. 

Adsorption is a surface phenomenon. When a multi-component fluid mixture is contacted with a solid adsorbent, certain components of the mixture (adsorbates) are preferentially concentrated (selectively adsorbed) near the solid surface creating an adsorbed phase. This is because of the differences in the fluid-solid molecular forces of attraction between the components of the mixture. The difference in the compositions of the adsorbed and the bulk fluid phases forms the basis of separation by adsorption. It is a thermodynamically spontaneous process, which is exothermic in nature. The reverse process by which the adsorbed molecules are removed from the solid surface to the bulk fluid phase is called desorption. Energy must be supplied to carry out the endothermic desorption process. Both adsorption and desorption form two vital and integral steps of a practical adsorptive separation process where the adsorbent is repeatedly used. This concept of regenerative use of the adsorbent is key to the commercial and economic viability of this technology. 

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