Big Chemical Encyclopedia

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

Articles Figures Tables About

Bases characteristics

The last part, following the method to analyse radioscopy and acoustic emission values, will be to correlate the characteristic values of the radioscopic detection of casting defects with extracted characteristic values of the acoustic emission analysis. The correlation between the time based characteristic values of acoustic emission analysis and the defect characterizing radioscopy values did not come to very satisfactory results referring the low frequency measurements. The reason can be found in the... [Pg.16]

Besides the material based characteristics, the difference of density of the used particle/substrate combination is a very important criterion. The difference of density influences the contrast of the radiographic tests. Tungsten carbides were used as mechanically resistant particles and titanium based alloys as substrate. The substrate material is marked by an advantageous relation of strength to density. This material is often used in aeronautics, astronautics, and for modification of boundary layers. The density of tungsten carbide (15.7 g/cm ) is about 3.5 times higher than the density of titanium (4.45-4.6 g/cm ). [Pg.543]

The importance of laser light, in brief, is tliat its base characteristics, coherence, spectral and polarization purity, and high brilliance allow us to manipulate its properties. Gain switching [i, 10] and mode locking [16] are prime examples of our ability to very specifically control tire laser output. It is easy to see why lasers are tire ideal sources for optoelectronic applications. [Pg.2863]

Lysine and aspartic acids are two of the amino acids found in proteins. Describe the acid-base characteristics of these compounds. [Pg.1234]

Theobald, D. L. Rapid calculation of RMSDs using a quaternion-based characteristic polynomial. Acta Crystallogr. 2005, A61, 478 80. [Pg.204]

An easy way to quantify the adsorptive and acid/base characteristics of a column is to measure the peak height as a percentage of that expected for complete and undisturbed elution. The two alkanes and three fatty acid methyl esters (non-adsorbing peaks) are connected at their apexes to provide the 100% line as shown in Figure 2.8 [190]. The column activity is then quantified... [Pg.87]

The only means by which inorganic wastes can be rendered nonhazardous are dilution, isolation (as in deep-well injection), in some cases changes in oxidation state, and neutralization. Acidic wastes made up one-fifth of the injected waste volume and involved one-third of the injection wells in 1983. Most of the volume was from inorganic acids (hydrochloric, sulfuric, and nitric). Acid-base characteristics and neutralization were discussed in detail earlier, so the remainder of this section will focus on heavy metals and other hazardous inorganics (selenium and cyanide). [Pg.819]

The 0-order rate constant, k()p is a maximal volume-based characteristic value for a biofilm and a substrate ... [Pg.31]

Absorption from the GI tract is controlled by a variety of factors. These include the acid-base characteristics of the chemical (called the pKa), the solubility, the nature of the delivery (e.g., diet vs. gavage), the nature of any vehicle (suspensions vs. solution, or aqueous vs. nonaqueous), and the gastrointestinal tract of the species under study. [Pg.699]

Extensive tabulations on experimentally determined surface equilibrium constants (Schindler and Stumm, 1987 Dzombak and Morel, 1990) reflecting the acid-base characteristic of surface hydroxyl groups and the stability of surface metal com-... [Pg.32]

In summary, the model proposed on the basis of acid-base characteristics of kaolinite platelets explains the pH-dependent charge primarily to the protonation of the hydroxyl groups at the basal gibbsite and the edge surface. We will later illustrate how this charge characteristics (surface protonation) influences the reactivity (dissolution characteristics) of kaolinite. [Pg.65]

The chemical, biological, and physical characteristics of the drug substance can be manipulated and hence optimized by conversion to a salt form. Every compound that exhibits acid or base characteristics can participate in salt formation. Various salts of the same compound often behave quite differently because of the physical, chemical, and thermodynamic properties they impart to the parent compound. Table 1 lists the top ten FDA approved commercially marketed final drug forms and Table 2... [Pg.247]

All studies show the zwitterionic nature of the spiropyran merocyanine beyond any doubt and we can further see how the acid-base characteristics of the C9 oxygen and indoline nitrogen are delocalized as alternating charges on the methine bridge, leading to the labile properties of the bridge itself. [Pg.382]

Aramendia et al. (22) investigated three separate organic test reactions such as, 1-phenyl ethanol, 2-propanol, and 2-methyl-3-butyn-2-ol (MBOH) on acid-base oxide catalysts. They reached the same conclusions about the acid-base characteristics of the samples with each of the three reactions. However, they concluded that notwithstanding the greater complexity in the reactivity of MBOH, the fact that the different products could be unequivocally related to a given type of active site makes MBOH a preferred test reactant. Unfortunately, an important drawback of the decomposition of this alcohol is that these reactions suffer from a strong deactivation caused by the formation of heavy products by aldolization of the ketone (22) and polymerization of acetylene (95). The occurrence of this reaction can certainly complicate the comparison of basic catalysts that have different intrinsic rates of the test reaction and the reaction causing catalyst decay. [Pg.251]

Isomerization of jS-isophorone to a-isophorone has been represented as a model reaction for the characterization of solid bases 106,107). The reaction involves the loss of a hydrogen atom from the position a to the carbonyl group, giving an allylic carbanion stabilized by conjugation, which can isomerize to a species corresponding to the carbanion of a-isophorone (Scheme 9). In this reaction, zero-order kinetics has been observed at 308 K for many bases, and consequently the initial rate of the reaction is equal to the rate constant. The rate of isomerization has been used to measure the total number of active sites on a series of solid bases. Figueras et al. (106,107) showed that the number of basic sites determined by CO2 adsorption on various calcined double-layered hydroxides was proportional to the rate constants for S-isophorone isomerization (Fig. 3), confirming that the reaction can be used as a useful tool for the determination of acid-base characteristics of oxide catalysts. [Pg.253]

Lead monoxide is amphoteric in nature i.e., the oxide exhibits both the acid (weakly acidic) and base characteristics. It dissolves in acids forming their corresponding salts ... [Pg.474]

Each of the three definitions expands our concept of acids and bases. Arrhenius basic definition is adequate for understanding many of the properties of acids and bases. It is important to recognize, though, that acids and bases are not fixed labels that can be applied to a substance. Bronsted-Lowry and Lewis showed that acid-base characteristics are dependent on the reactions that take place between substances. A... [Pg.159]

Fluxes vary in characteristics such as degree of covalency, acid-base characteristics and redox behavior. While chemical reasoning may provide some insights into appropriate choices of suitable fluxes, an empirical approach to the problem is usually necessary to produce crystals of a new compound. [Pg.234]

Lately the most frequently used technique for the determination of thermodynamic and acid/base characteristics is inverse gas chromatography [30,73-75]. In IGC the unknown filler or fiber surface is characterized by compounds, usually solvents, of known properties. IGC measurements can be carried out in two different ways. In the most often applied linear, or ideal, IGC infinite concentrations of n-alkane are injected into the column containing the filler to be characterized. The net retention volume (V ) can be calculated by ... [Pg.134]

The traditional view of stagnation flow was presented in the previous sections, that is, a semi-infinite inviscid potential flow interacting with a thin viscous boundary layer near the stagnation surface. In that case there is no physically based characteristic length scale. [Pg.267]

Acid-base characteristics of silane-treated E glass fiber surfaces... [Pg.379]

This effect was used to prepare the tetrahydropyranyl ether (3) of racemic phytosphingosine,2 a base characteristic of plant sphingolipids (equation II). [Pg.487]

Niederer [100] used ion trap mass spectrometry and negative ion chemical ionisation to determine nitro- and oxypolyaromatic hydrocarbons in soils. Meyer et al. [101] have described a simple and reproducible method which provides the simultaneous determination of polycyclic aromatic hydrocarbons and het-eropolycyclic aromatic hydrocarbons (N, S, O) and their metabolites in contaminated soils. Contaminants extracted from the soil sample were separated by polarity and acid-base characteristics using solid-phase extraction on silica gel and a strong basic anion exchange material. A subfraction containing PANHs and neutral metabolites was subsequently fractionated into neutral and basic... [Pg.96]

Table 3. 1H-NMR spectrum of ketotifen base characteristics and assignments... Table 3. 1H-NMR spectrum of ketotifen base characteristics and assignments...

See other pages where Bases characteristics is mentioned: [Pg.15]    [Pg.144]    [Pg.202]    [Pg.42]    [Pg.104]    [Pg.531]    [Pg.298]    [Pg.531]    [Pg.613]    [Pg.237]    [Pg.69]    [Pg.10]    [Pg.187]    [Pg.30]    [Pg.430]    [Pg.293]    [Pg.67]    [Pg.253]    [Pg.354]    [Pg.153]    [Pg.97]    [Pg.380]    [Pg.107]    [Pg.102]   
See also in sourсe #XX -- [ Pg.352 ]

See also in sourсe #XX -- [ Pg.675 , Pg.676 , Pg.677 , Pg.678 , Pg.679 ]

See also in sourсe #XX -- [ Pg.83 ]




SEARCH



Acid-base, generally equilibria, characteristics

Acid/base characteristics

Anion acid/base characteristics

Behavior-based safety characteristics

Characteristics of textile-based implant materials

Complex bases characteristics

Compressor characteristics based

Crystals Based on Intrinsic Hydrogen-Bonding Characteristics (Lacking Preorganization)

Indicators acid-base, characteristics

Knowledge-based studies, molecular characteristics

Novolac-based resist, characteristics

Physicochemical Characteristics of Nanosystems Based on Endogenous Polymers

Physiologically based pharmacokinetic characteristics

Rubber-based adhesives: typical characteristics

Skill 12.11-Based on position in the periodic table, predict which elements have characteristics of metals, semimetals, nonmetals, and inert gases

Supply Base Characteristics

Suppository bases melting characteristics

Technical requirements of slurry surfacing based on visual assessment and surface characteristics

Zeolite-based membranes characteristics

© 2024 chempedia.info