Oriental water content

In the polymer industry, packing material, laminates including multilayer films, pellets or molded products can be analyzed by NIR. Even polymer latex particles with up to 99 % water content may be analyzed. NIR provides information about reaction mechanisms, polymerization, crystallinity, orientation, water content and hydrogen bonding, even during the process of polymer manufacture. For example the disappearance of the double bonds in polyethylene and polypropylene can be monitored. In the NIR spectrum C=C bonds lead to a combination band at about 4740 cm and a first overtone at about 6170 cm NIR spectroscopy is applied to characterize ester-, nitrile-, or amide-based acrylic and methacrylic polymers. Other examples are the identification of polyvinylchloride, polyvinyl alcohol and polyvinyl acetates or the analysis of polymerization in epoxy and phenolic resins. 

Wetzel, R., Zirwer, D., Becker, M. Optical anisotropy of oriented deoxyribonucleic acid films of diffi-rcrit water content. Biopolymers 8 (1969) 391-401... 

Tofu has long been a source of protein in the Orient. It has much the same importance to the people of the Orient that meats, eggs and cheese have for the people in Western Countries. Tofu is usually sold in the form of a wet cake with a creamy-white color, smooth custard-like texture and a bland taste. It is highly hydrated and, depending on the water content, tofu products with different characteristics can be produced. The typical oriental type of tofu has a water content about 85%. Japanese prefer tofu having a smooth, fragile texture that contains about 88% water. The Chinese, on the other hand, produce many types of firm products with a chewy meatlike texture and a water content as low as 50-60%. Western consumers like tofu with a firm texture therefore, tofu found in the U.S. supermarkets contains 75-80% water. 

If the electrolyte is composed of HF and an organic solvent a dependence of n on the kind of solvent and on the residual water content is observed, while the substrate orientation showed no effect on ru, [Chl5],... 

Polyolefin foams are easier to model than polyurethane (PU) foams, since the polymer mechanical properties does not change with foam density. An increase in water content decreases the density of PU foams, but increases the hard block content of the PU, hence increasing its Young s modulus. However, the microstructure of semi-crystalline PE and PP in foams is not spherulitic, as in bulk mouldings. Rodriguez-Perez and co-workers (20) showed that the cell faces in PE foams contain oriented crystals. Consequently, their properties are anisotropic. Mechanical data for PE or PP injection mouldings should not be used for modelling foam properties. Ideally the mechanical properties of the PE/PP in the cell faces should be measured. However, as such data is not available, it is possible to use data for blown PE film, since this is also biaxially stretched, and the texture of the crystalline orientation is known to be similar to that in foam faces. 

In contrast to soft biologies, whose mechanical properties primarily depend upon the orientation of collagen fibers, the mechanical properties of mineralized tissues, or hard biologies, are more complicated. Factors such as density, mineral content, fat content, water content, and sample preservation and preparation play important roles in mechanical property determination. Specimen orientation also plays a key role, since most hard biologies such as bone are composite structures. For the most part, we will concentrate on the average properties of these materials and will relate these values to those of important, man-made replacement materials. 

In addition to diffraction methods, also spectroscopic techniques, especially NMR spectroscopy, are extensively used to study the complex interaction of water and the clay mineral surfaces. NMR spectroscopy has become a valuable tool to investigate the dynamics of water [41, 48-54]. The study of interaction of water with clays using NMR techniques has primarily involved measurements of H and 2H spin-lattice relaxation and lineship analysis of H and 2H in water molecules adsorbed on clays [32, 41, 51-54], Based upon the results of such studies, it is possible to calculate the distribution, orientation, and diffusion rates of water molecules bound to clays. It was found that water molecules have a preferential orientation on clays with low water contents at temperatures near 298K [52, 54]. 

Using MC simulations Delville and co-workers have investigated the clay-water interface [83-87], The number of hydration layers (2-3) increases suddenly during the swelling process [85]. For hydrated montmorillonite with interlayer sodium counterions it was determined that the water content of the pore is a function of the interlamellar distance. Water molecules are layered in successive shells, whose number (1-4) depends on the available interlayer space [87]. The MD study of structure of water in kaolinite [88] has indicated two types of adsorbed water molecules according to different orientations with respect to the structure of clay sheets with HH vector parallel or perpendicular to the surface. 

The conversion of hexanoic acid as a function of time for the three different experiments is plotted in Fig. 8.27. For orientation, the maximally obtainable conversion if no water is removed from the mixture is also plotted (79 % under the chosen conditions). The lowest curve shows a blank experiment where the liquid flows over uncoated monoliths and reacts homogeneously. The second curve represents an experiment in the autoclave where the water removal is suppressed. The comparison of these two curves indicates that, without decreasing the water contents, the catalytic activity of the BEA cannot be used efficiently. The third (highest) curve proves the effect of reactive stripping. The reaction runs much faster and easily continues beyond the equilibrium. 

The nature of the charge carriers is not yet clear and there could be at least two possibilities ionic impurities or H-bond network defects (so-called orientation and ionic defects) similar to those considered in the conduction and relaxation of ice [242,243]. Conductivity behavior due to ionic impurity is expected to increase linearly with the impurity concentration per unit volume, and the impurities would be proportional to water content. However, the normalized conductivity did not show such a linear behavior (Fig. 39), although some tendency of increase with water content can be observed. This increase of the normalized conductivity does not immediately contradict the concept of defect-conductivity, because the number of defects can also be increased by increasing water content. At the very least, diffusion of ions should also be accompanied by breaking or changing of H-bond networks around the ion molecule. Such rearrangements of H-bond networks around ions can affect the EW and may influence the main relaxation process on a cluster level. Thus, the existence of universality is most likely due to the presence of an H-bond network and its defect structure. 

In contrast to more established spectroscopic techniques, SS-NMR spectra are virtually independent of the physical properties of the sample, such as particle size, homogeneity, or residual water content. Therefore, pharmaceutical solids can be studied by NMR without a need for special sample preparations. Samples viable for SS-NMR analysis include a whole range of pharmaceutical formulations such as tablets, lyophilized powders, capsules, suspensions, and ointments. SS-NMR does not suffer from a preferred orientation restriction, which often leads to an incorrect identification of polymorphs when using XRPD. In addition, SS-NMR is a nondestructive technique that allows other analyses to be performed on the same sample after the NMR spectrum is acquired. 

Gallic acid functions as an effective silicon complexing agent in aqueous ethanolamine solutions. In the absence of it the etch rate is zero. Etch rate increases with water content. The additions of pyrazines, pyridazines, and triazoles show various catalytic effects on the etching process [140]. The catalysts that lead to faster oxidation result in faster etch rates, and the difference among the catalysts is attributed to a steric effect. Oxidative catalysts tend to influence the etching selectivity of the major crystal orientations [94]. 

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