Non-destructive Methods

A new, non destructive method has been developed for testing high strength bolts which is based on measuring the magnetic stress on the head of a bolt. The forces originating in the body of the bolt can be determined in this way since these forces are proportional to the stress state in the head of the bolt. 

Oxides (Ln Oj), fluorides (LnF ), sulfides (Ln S, LnS), sulfofluorides (LnSF) of lanthanides are bases of different functional materials. Analytical control of such materials must include non-destructive methods for the identification of compound s chemical forms and quantitative detenuination methods which does not require analytical standards. The main difficulties of this analysis by chemical methods are that it is necessary to transform weakly soluble samples in solution. 

The thickness of the absorbent on the TLC plates could be between 0.2mm to 2mm or more. In preparative work, the thicker plates are used and hundreds of milligrams of mixtures can be purified conveniently and quickly. The spots or areas are easily scraped off the plates and the desired substances extracted from the absorbent with the required solvent. For preparative TLC, non destructive methods for visualising spots and fractions are required. As such, the use of UV light is very useful. If substances are not UV active, then a small section of the plate (usually the right or left edge of the plate) is sprayed with a visualising agent while the remainder of the plate is kept covered. 

Crystalline material will diffract a beam of X-rays, and X-ray powder diffractometry can be used to identify components of mixtures. These X-ray procedures are examples of non-destructive methods of analysis. 

Some information relevant to the choice of appropriate methods is given in condensed form in Table 1.1, which is divided into three sections the classical techniques a selection of instrumental methods some non-destructive methods. 

It must be stressed, however, that the whole object may be the analytical sample, e.g. a specimen of moon-rock. Ideally this sample would be analysed by non-destructive methods. Occasionally the bulk material may be homogeneous (some water samples) and then only one increment may be needed to determine the properties of the bulk. This increment should be of suitable size to provide samples for replicate analyses. 

For this particular product, in addition to a decrease in analysis time, a non-destructive method is especially desirable because of other physical tests that are also required on each sample By FNAA, the total nitrogen content of a sample is first detd and then related to compn of the mixture. Since Octols contain no ingredients other than pure TNT (18.50% N) and pure HMX (37.84%), the following linear relationship is derived from the ealed nitrogen content of each ingredient ... 

Various destructive and non-destructive methods of analysis have been tested and H-l and C-13 NMR have, among other techniques provided valuable structural information on soluble humic acids and fulvic acids 48, Humin, on the other hand has withstood detailed non-destructive analysis. 

All the analytical methods mentioned to separate, identify, and quantify chlorophylls and derivatives consume time, money, and samples. As alternatives, industries have been employing non-destructive methods for surface color measurements that are not only indirectly related to chlorophyll content, but may also estimate the pigments directly in tissues, leaving the sample intact and enabling serial analyses in a relatively short time. Eood color affects consumer acceptance and is an important criterion for quality control. Color vision is a complex phenomenon that depends on both the total content and number of pigments and also on absorption, reflectance and emission spectra of each compound present. 

The use of differential UV spectroscopy is a facile analytical tool, providing a rapid, non-destructive method for determining the course and extent of degradation of PC films during accelerated or natural weathering. 

Dinkelaker B., Hahn G., Romheld V., Wolf G.A, Marschner H. Non-destructive methods for demonstrating chemical changes in the rhizosphere 1. Description of method. Plant Soil 1993 155/156 67-70. 

It is obvious that the simpler a method of analysis, the easier it will be to automate. Non-destructive methods which involve a minimum of sample treatment are the most attractive. X-ray fluorescence, for example, has been successfully applied to the continuous monitoring and control of process streams. However, the scope of automated analysis is wide and methods have been designed with a basis in nonspecific properties (pH, conductance, viscosity, density) as well as those characteristic of the che-... 

There is constant development and change in the techniques and methods of analytical chemistry. Better instrument design and a fuller understanding of the mechanics of analytical processes enable steady improvements to be made in sensitivity, precision, and accuracy. These same changes contribute to more economic analysis as they frequently lead to the elimination of time-consuming separation steps. The ultimate development in this direction is a non-destructive method, which not only saves time but leaves the sample unchanged for further examination or processing. 

The aspects which relate to the homogeneity of the sample have to be considered in the context of the nature of the analytical process. Also the nature of the analytical process is determined by the characteristics of the sample to be analysed. Hence the two groups of analytical methods, destructive and non-destructive, should be considered separately. Although both groups have wide applicability, the analytical chemist has a tendency to prefer the non-destructive methods. Since such methods act directly upon the sample, they have the advantage of partly—and with some precautions, totally—eliminating the risk of contamination of the sample. 

The choice of one or other of the methods depends on the nature of the sample. Generally, the non-destructive methods are applied to samples with relatively simple composition. However, for more complex samples or when the determination of major and minor components is required, preliminary separation of the components and concentration of the minor or trace components are necessary, before the actual determination may be performed. It follows therefore, that the analytical chemist must resort in many cases, willingly or not, to destructive methods of analysis. 

Spectroscopic techniques such as electron spin resonance (ESR) offer the possibility to "probe" the chemical environment of the interlayer regions. With the ESR technique, an appropriate paramagnetic ion or molecule is allowed to penetrate the interlayer, and chemical information is deduced from the ESR spectrum. Transition metal ions, such as Cu2+, and nitroxide radical cations, such as TEMPAMINE (4-amino-2,2,6,6-tetramethylpiperidine N-oxide) have been used as probes in this manner (6-14). Since ESR is a sensitive and non-destructive method, investigations of small quantities of cations on layer silicate clays at various stages... 

In general, the changes incurred are usually minimal and for this very reason the UV-spectrophotometry is considered to be a non-destructive method of analysis. 

A quick and non-destructive method for measuring relative reactivities of two nucleophiles towards the same aryl radical derives from repetitive cyclic voltammetry of a solution containing the substrate and the two nucleophiles (Amatore et ai, 1985b). The ratio of the peak heights corresponding to the two substitution products provides straightforwardly the ratio of the two rate constants. 

The PSO-Eltra project is a Pre-pilot SOFC production plant designed to scale-up existing laboratory production methods, build the necessary know-how for establishing industrial production, improve reproduction possibilities and develop non-destructive methods for production control. The project ran from 2001-2003, participants included Riso, HaldorTopsoe, and Eltra. 

One of the great strengths of X-ray fluorescence analysis comes from the fact that it is a non-destructive method that can be used on samples without the need for prior treatment. 

Chemical analysis is the proof of many innovations the evolution of technologies has led to the development of high-performance instruments allowing new possibilities, notably hyphenated methods and non-destructive methods. Non-destructive tests can be conducted on very small samples that do not necessitate extensive sample preparation. Users can finally acquire instruments that meet the quality and precision requirements necessary to obtain certification. This latter requirement is an important if not a sufficient condition to officially recognise the quality of results produced by a laboratory. Certification procedures are enforced by a number of testing bodies all over the world. 

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