Nondestructive analytical

This can result in a radioactive product from the A(n, t)A reaction where A is the stable element, n is a thermal neutron, A is the radioactive product of one atomic mass unit greater than A, and y is the prompt gamma ray resulting from the reaction. A is usually a beta and/or gamma emitter of reasonably long half-life. Where access to a nuclear reactor has been convenient, thermal neutron activation analysis has proven to be an extremely valuable nondestructive analytical tool and in many cases, the only method for performing specific analyses at high sensitivities... 

Nondestructive radiation techniques can be used, whereby the sample is probed as it is being produced or delivered. However, the sample material is not always the appropriate shape or size, and therefore has to be cut, melted, pressed or milled. These handling procedures introduce similar problems to those mentioned before, including that of sample homogeneity. This problem arises from the fact that, in practice, only small portions of the material can be irradiated. Typical nondestructive analytical techniques are XRF, NAA and PIXE microdestructive methods are arc and spark source techniques, glow discharge and various laser ablation/desorption-based methods. On the other hand, direct solid sampling techniques are also not without problems. Most suffer from matrix effects. There are several methods in use to correct for or overcome matrix effects ... 

Also the consumer s needs—exactly like the manufacturer s ones— require rapid, effective, low-cost, and nondestructive analytical techniques, in order to accomplish a widespread control and achieve broader quality assurances saving the costs. 

Because of the nature of the samples involved in this study, special, preferably nondestructive analytical procedures must be used. In addition most museums will not permit, or at least find it difficult to arrange for, the transfer of a coin or art object to an outside laboratory. Further, the types of data to be acquired will generally be significant only if a statistically large number of samples is analyzed. These problems are all quite different from those normally encountered in analytical chemistry and thus restrict in some cases the accuracy and precision of the data. 

Layer charges can be calculated from mineral and chemical composition. Mineral composition can be determined by the comparison of x-ray diffraction and thermal analytical and surface area studies. Chemical composition is determined by a total chemical analysis of the sample. In the classical method, chemical analysis is made after acidic dissolution (Ross and Hendricks 1945). Nowadays, nondestructive analytical methods (e.g., electron microscopy, prompt gamma activation analysis, etc.) are also applied. Chemical composition is usually given as oxides (e.g., Si02, A1203, etc.). The cations are divided into three groups ... 

Photoacoustic spectroscopy (PAS) is a nondestructive analytical technique in which light entering the photoacoustic cell passes through undetected if the sample is nonabsorbing, but heats up and expands the gas in the cell if the light is absorbed. This expansion makes an audible sound whenever absorption occurs and is detected by a microphone. The SNR may increase with the sample surface area. PAS determinations were carried out for hfac chelates of Sc, Y and the rare earth Ce, Pr, Nd, Eu and Er. ... 

FTIR microscopy, in which IR spectra can be obtained from picogram quantities, is an invaluable nondestructive analytical tool in fields such as forensic science and pharmaceutical analysis. 

Nuclear activation methods can provide high sensitivities for many but not all elements. These methods are capable of simultaneous multielement analysis and in some cases they may be essentially nondestructive analytical methods. One of the main disadvantages is the lack of information on chemical form (speciation) of the elements in the analyte. Neutron activation analysis is the most common form of activation analysis, but charged particle and photon activation analysis methods are also applied. 

Micro-PIXE offers a powerful nondestructive analytical method of micrometer-scale lateral resolution for research in art and archeology. Among other fields of application studies in corrosion processes, searching for characteristic features of painting and fabrication techniques, identification of art objects through trace element qualifications, and testing of restoration methods can be mentioned here. 

An important variant of this method is to use a nondestructive analytical method in which the composition... 

Other features are the following (1) the possibility of non-vacuum use, especially in the case of ion-y reactions, where the outgoing y rays are detected (this feature allows the analysis of volatile samples or those with extended dimensions), (2) the simultaneous applicability with RBS and/or PIXE, (3) the easy preparation of the samples, and last but not least, (4) it is a nondestructive analytical method. 

The disadvantage of ellipsometry is undoubtedly that it does not represent a direct analytical method, but attempts to match functional relationships as well as possible to the experimental data by the development of models [93]. On the other hand, ellipsometry is one of the few nondestructive analytical methods that allows measurement of the monolayer or submonolayer. However, even when a microspot" of measuring light is used, it represents several square millimeters in area. In this surface area, the product nd (optical film thickness) is averaged laterally. 

Near-infrared spectroscopy (NIR), which is a nondestructive analytical technique, has been employed for the simultaneous prediction of the concentrations of several substrates, products, and constituents in the mixture sampled from fermentation process. In this chapter, applications of NIR to monitoring of the various fermentation processes are introduced. The fermentation processes mentioned here are wine, beer, Japanese sake, miso (soybean paste), soy sauce, rice vinegar, alcohol, lactic acid, glutamic acid, mushroom, enzymatic saccharification, biosurfactant, penicillin, and compost. The analysis of molasses, which is a raw material of fermentation, with NIR is also introduced. These studies indicate that NIR is a useful method for monitoring and control of fermentation process. 

Most of the early users of NIR spectroscopy were, with few exceptions, working in the field of agriculture, taking advantage of this new nondestructive analytical tool and having low or no interest to further exploit the spectroscopy behind the data in scientific depth. 

Using synchrotron transmission FTIR microspectroscopy as a rapid, direct and nondestructive analytical technique to reveal molecular microstructural-chemical features within tissue in grain barley. /. Agric. Food Chem., 52 (6),... 

In short, MCD is an exceptionally sensitive, accurate, and nondestructive analytical method for tryptophan quantitation and modification. Its extension promises to be of great value to many aspects of composition, structure, and function of protein molecules. 

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