Carry-through properties

Carry through properties Very good Fair-Good Fair-Good Poor Good... 

In most countries, use of synthetic antioxidants is regulated and the safety of the compounds involved has been tested based on long-term toxicity studies. The ability of an antioxidant to withstand thermal treatment (e.g., frying or baking) and to retain sufficient stabilizing activity for the food (fried or baked) is termed as carry through property. Table 6 provides a summary of physical properties of commonly used synthetic antioxidants. Several researchers have smdied the effectiveness of these compounds in suppressing lipid oxidation in fats and oil, and Tables 7 and 8 provide comparative effects of synthetic antioxidants (82). 

Butylated Hydroxytoluene (BHT) BHT is also a monohydroxyphenol (Figure 4) and is widely used in foods. This fat-soluble antioxidant is available as a white crystalline compound. BHA is less stable than BHT at high temperatures and has lower carry-through properties. BHA and BHT act synergistically, and several commercial antioxidant formulations contain both of these antioxidants. BHT is effectively used in oxidation retardation of animal fats. It is postulated that BHA... 

The method using GC/MS with selected ion monitoring (SIM) in the electron ionization (El) mode can determine concentrations of alachlor, acetochlor, and metolachlor and other major corn herbicides in raw and finished surface water and groundwater samples. This GC/MS method eliminates interferences and provides similar sensitivity and superior specificity compared with conventional methods such as GC/ECD or GC/NPD, eliminating the need for a confirmatory method by collection of data on numerous ions simultaneously. If there are interferences with the quantitation ion, a confirmation ion is substituted for quantitation purposes. Deuterated analogs of each analyte may be used as internal standards, which compensate for matrix effects and allow for the correction of losses that occur during the analytical procedure. A known amount of the deuterium-labeled compound, which is an ideal internal standard because its chemical and physical properties are essentially identical with those of the unlabeled compound, is carried through the analytical procedure. SPE is required to concentrate the water samples before analysis to determine concentrations reliably at or below 0.05 qg (ppb) and to recover/extract the various analytes from the water samples into a suitable solvent for GC analysis. 

FTA [5-7] is a version of continuous-flow analysis based on a nonsegmented flowing stream into which highly reproducible volumes of sample are injected, carried through the manifold, and subjected to one or more chemical or biochemical reactions and/or separation processes. Finally, as the stream transports the Anal solution, it passes through a flow cell where a detector is used to monitor a property of the solution that is related to the concentration of the analyte as a... 

Considerable efforts have also been made toward the development of novel compounds with superior antioxidant properties. Some attempts were also made to introduce new synthetic polymeric compounds which are non-absorbable and non-toxic. These are generally hydroxyaromatic polymers with various alkyl and alkoxyl substitutions. Such compounds are usually very large molecules and their absorption from the intestinal tract is practically nil. In addition to their reportedly high antioxidant activity, they are non-volatile under deep-fat frying conditions, which result in nearly quantitative carry-through to the fried items, but they have not yet received FDA approval. 

Another source of error in the investigation of the surface properties of titanium dioxide is its tendency to adsorb acids or ions. Phosphate ions are very strongly adsorbed (see Table XIX) as well as sulfuric acid. Commercial pigments often have considerable sulfate contents. When titania is precipitated from sulfate solution, sulfate ions are strongly adsorbed (308). They are carried through all further stages of pigment manufacture. 

The ionization properties of side-chain substituents will usually carry through into the peptide or protein and influence the behaviour of the polymer. However, the actual pATa values of the amino acid side-chains in the protein are modified somewhat by the position of the amino acid in the chain, and the environment created by other substituents. Typical pATa values are shown in Table 13.2. 

Write the steady-state mass and heat balance equations for this system, assuming constant physical properties and constant heat of reaction. (Note Concentrate your modeling effort on the adiabatic nonisothermal reactor, and for the rest of the units, carry through a simple mass and heat balance in order to define the feed conditions for the reactor.)... 

If the desorption rate is sufficiently large, chromatographic separation and analyses of mixed suspensions become possible. Dependence of adsorption and desorption rates upon particle properties causes some components of a pulse of mixed particles carried through a packed bed to be eluted more quickly than others. This mechanism is analogous to conventional gas chromatography, and all the formalisms developed for the latter may be applied. 

The approach that will be used in this text is different, in that the description of electronic structures is greatly simplified to provide a more vivid understanding of the properties numerical estimates of properties will be obtained with calculations that can be carried through by hand rather than machine. We shall concentrate on the physics of the problem. In this context a scmicmpirical determination of matrix elements is appropriate. The first attempt at this (Harrison, 1973c) followed Phillips (1970) in obtaining the principal matrix element Kj from the measured dielectric constant. A second attempt (Harrison and Ciraci,... 

Atomic-like f electron states in condensed matter were first studied in rare-earth and actinide metallic or non metallic compounds. There the multiplicity of the f states and related properties like magnetic moment, Curie-Weiss susceptibilities and spectra (where the crystal field splitting is measured) indicate that for most of the rare-earth series (RE) it is a good approximation indeed to consider those f electrons as atomic-like states. Then for the calculation of properties we can treat the f electrons in those compounds within the same approximations as for the core electrons and assume that the interaction between f electrons in different sites is carried through the conduction or the valence electrons. 

The goal of electronic-structure calculations is to provide information on real materials. The field of electronic-structure calculations is therefore placed somewhere between experiment and theory. I.e., by carrying through such calculations on specific systems one obtains results that cannot be manipulated but instead have to be interpreted. This resembles the situation of experiment. On the other hand, by modifying the systems one is able to follow the changes in the properties also to idealized situations that lie outside the range of experiment, which is a typical approach within theory. 

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