Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Properties Characteristics that describe

Properties Characteristics that describe samples of matter. Chemical properties are exhibited as matter undergoes chemical changes. Physical properties are exhibited by matter with no changes in chemical composition. [Pg.41]

Chemical property characteristic that describes the ability of a substance to change to a different substance. [Pg.828]

Important characteristics that describe static mass, conformations, and dimensions of polymer molecules have been surveyed. This has been followed by hydrodynamic properties such as diffusion and viscosity. A separate section has been used to describe the salient aspects of charged polymers and colloids in solution. From there, the collective properties of polymers were briefly introduced in terms of their solution thermodynamics, the relationship of these to the scattering of light, and to phase behavior and transitions. Concentrated polymer solutions and melts become extraordinarily complex, with time response behavior depending on polymer architecture and interactions, and this has been briefly discussed in the area of rheology. In the solid-state limit of rheology, polymers take on myriad applications in materials engineering applications, in electronics, optics, and other areas. [Pg.104]

The correlation function provides a measure of how rapidly the values of a mechanical property change as a result of molecular collisions. We can define a characteristic time constant, called the correlation time of property A, that describes the relaxation of caa(0 from 1 to 0, as follows ... [Pg.207]

Properties. Hydroxypropylcellulose [9004-64-2] (HPC) is a thermoplastic, nonionic cellulose ether that is soluble in water and in many organic solvents. HPC combines organic solvent solubiUty, thermoplasticity, and surface activity with the aqueous thickening and stabilising properties characteristic of other water-soluble ceUulosic polymers described herein. Like the methylceUuloses, HPC exhibits a low critical solution temperature in water. [Pg.279]

Further developments have brought forth polymeric quats having antimicrobial properties (158—160). Different kinds of polyquats have been described with molecular weight from 2,000 to 60,000 (153). Polymeric quats have two characteristics that make them uniquely different from the monomeric quats. One is the absence of foaming, even at high concentrations. The other is their remarkably low toxicity in skin and eye irritation tests and... [Pg.129]

The elements are obtainable in a state of very high purity but some of their physical properties are nonetheless variable because of their dependence on mechanical history. Their colours (Cu reddish, Ag white and Au yellow) and sheen are so characteristic that the names of the metals are used to describe them. Gold can also be obtained in red, blue and violet colloidal forms by the addition of vtirious reducing agents to very dilute aqueous solutions of gold(III) chloride. A remarkably stable example is the Purple of Cassius , obtained by using SnCla as reductant, which not only provides a sensitive test for Au but is also used to colour glass and ceramics. Colloidal silver and copper are also obtainable but are less stable. [Pg.1177]

Special Characteristics Information that describes the functionality of the application needs to be handled in a specific manner. This information can include such properties as size, weight, geometric form, special functional elements, processing and assembly methods, and other product specific information. [Pg.606]

We have discussed the value of struts or columns in structural mechanics and described their linear elastic properties. They have another characteristic that is not quite so obvious. When columns are subject to a compressive load, they are subject to buckling. A column will compress under load until a critical load is reached. Beyond this load the column becomes unstable and lateral deformations can grow without bound. For thin columns, Euler showed that the critical force that causes a column to buckle is given by... [Pg.55]

Formula (2.2) contains only one-dimensional probability density W(xi, t ) and the conditional probability density. The conditional probability density of Markov process is also called the transition probability density because the present state comprehensively determines the probabilities of next transitions. Characteristic property of Markov process is that the initial one-dimensional probability density and the transition probability density completely determine Markov random process. Therefore, in the following we will often call different temporal characteristics of Markov processes the transition times, implying that these characteristics primarily describe change of the evolution of the Markov process from one state to another one. [Pg.360]

The method used for the safe installation of pressure relief devices is illustrated in Figure 8-1. The first step in the procedure is to specify where relief devices must be installed. Definitive guidelines are available. Second, the appropriate relief device type must be selected. The type depends mostly on the nature of the material relieved and the relief characteristics required. Third, scenarios are developed that describe the various ways in which a relief can occur. The motivation is to determine the material mass flow rate through the relief and the physical state of the material (liquid, vapor, or two phases). Next, data are collected on the relief process, including physical properties of the ejected material, and the relief is sized. Finally, the worst-case scenario is selected and the final relief design is achieved. [Pg.353]

The aim of this chapter is to discuss fluorescence concepts that are used in selected immunoassay applications. The primary focus is on fluorescence topics of recent interest that provide insight into the characteristic properties of antibodies and antigens in immunoassays, or that describe enhancements in immunoassay technologies. The basic reagents and instrumentation required for immunoassay purposes are discussed first, followed by a brief description of immunoassay formats. The principles that are utilized in various fluorescence immunoassay technologies are outlined with specific examples and their significance. Since it is beyond the scope of this chapter to review all of the applications of fluorescence immunoassays, apologies are extended to authors that this chapter fails to cite. A number of comprehensive treatments of fluorescence immunoassay (FIA) applications and related topics are available. 18 ... [Pg.450]

The use of DPH lifetimes for the analysis of phase separations and membrane properties has been described for mode) systems.n fl) In the case of both parinaric acids and DPH, one of the motivations for examining phase separation in a model lipid bilayer is the possibility that phase separations might be detectable in natural membranes. However, this technique has not been able to satisfactorily resolve lateral phase separations in natural membranes, either because they do not exist or because they are much more complex and even possibly transient in nature. Alternatively, it could be argued that if a probe could be found with the characteristics of trans-parinaric acid but perhaps with an even greater phase partitioning ability, then this approach might be reevaluated. [Pg.233]

Since these early discoveries, xylose isomerases have been isolated from many bacterial species, and these enzymes have been intense investigated, especially those of the genera Streptomyces, Lactobacillus, and Bacillus. The characteristics of substrate specificity (xylose glucose > ribose), divalent metal cation activation (Mg, Mn or Co ), and activity at alkaline pH are properties that most of the enzymes share to a certain extent, but significant variations exist. Some of these em es have been immobilized and patented for commercial use. There are many good reviews in the literature that describe the enzymatic characteristics of the xylose isomerases 9,28,29). [Pg.487]

Further analysis is based on the idea that the characteristic experimental behavior of different classes of compounds and the suitability of those or other models used to describe this behavior is ultimately related to the extent to which the chromophores or electron groups physically present in the molecular system are reflected in these models. It is easy to notice, that the MM methods work well in case of molecules with local bonds designated in Table 1 as valence bonds the QC methods apply both to the valence bonded systems, and for the systems with delocalized bonds (referred as orbital bonds in Table 1). The TMCs of interest, however, not covered either by MM or by standard QC techniques can be physically characterized as those bearing the d-shell chromophore. The magnetic and optical properties characteristic for TMCs are related to d- or /-states of metal ions. The basic features in the electronic structure of TMCs of interest, distinguishing these compounds from others are the following ... [Pg.477]


See other pages where Properties Characteristics that describe is mentioned: [Pg.123]    [Pg.564]    [Pg.40]    [Pg.9]    [Pg.269]    [Pg.304]    [Pg.484]    [Pg.123]    [Pg.10]    [Pg.403]    [Pg.284]    [Pg.86]    [Pg.575]    [Pg.655]    [Pg.5]    [Pg.155]    [Pg.97]    [Pg.229]    [Pg.302]    [Pg.6]    [Pg.252]    [Pg.325]    [Pg.350]    [Pg.469]    [Pg.110]    [Pg.116]    [Pg.41]    [Pg.39]    [Pg.204]    [Pg.334]    [Pg.140]    [Pg.267]    [Pg.69]   


SEARCH



Characteristic properties

© 2024 chempedia.info