Glass objects, analyses

Sayre, E. V. (1965). Refinement in methods of neutron activation analysis of ancient glass objects through the use of lithium drifted germanium diode counters. In Comptes Rendus Vile Congres International du Verre, Bruxelles, 28 Juin-3 Juillet 1965, Charleroi, Institut National du Verre. 

Measurement of physical properties enables glass fragments to be divided into many different groups, but relatively little information is obtained as to the source of the broken glass object from which the fragments have originated. Elemental analysis can assist in ... 

Finite element analysis (FEA) or finite element modelling (FEM) decomposes a solid into a mesh made of discrete elements. For each element, the relevant parameters are supposed to be known (physical, chemical, mechanical properties) or locally determined (stress, temperature). Then after each increment of time the overall behaviour of the object can be determined. A step-by-step procedure is used to determine the behaviour of a glass object with time. Notably, when the shape varies the mesh has to be redefined continuously. This technique has become widely used since it allows complex loading and geometries to be considered that make it very attractive for industry and R D. 

Light microscopy is of great importance for basic research, analysis in materials science and for the practical control of fabrication steps. Wlien used conventionally it serves to reveal structures of objects which are otherwise mvisible to the eye or magnifying glass, such as micrometre-sized structures of microelectronic devices on silicon wafers. The lateral resolution of the teclmique is detennined by the wavelength of tire light... 

Chemical Analysis. The chemical composition of ancient objects is important for their authentication. The nature as well as the relative amounts of major, minor, and trace elements in any object are of use for determining the authenticity or otherwise of ceramics, glass, or alloys. A wide range of analytical techniques, depending on the nature of the material studied, have been used for this purpose, including X-rays fluorescence analysis, mass spectrometry, atomic absorption spectroscopy, and neutron activation analy-... 

Dynamic SIMS is used for depth profile analysis of mainly inorganic samples. The objective is to measure the distribution of a certain compound as a function of depth. At best the resolution in this direction is < 1 nm, that is, considerably better than the lateral resolution. Depth profiling of semiconductors is used, for example, to monitor trace level elements or to measure the sharpness of the interface between two layers of different composition. For glass it is of interest to investigate slow processes such as corrosion, and small particle analyses include environmental samples contaminated by radioisotopes and isotope characterization in extraterrestrial dust. 

The substrates used for DNA immobihsation can be, at the level of the AFM analysis, either rigid (e.g., glass) or flexible (e.g., polymers). An atomically flat surface is preferable, but sometimes this is difficult to achieve. The DNA immobilisation mechanisms can be (i) physio-sorption, (ii) charge complementarity and (iii) covalent binding. Depending on the actual objective of the AFM study, each combination of the surface-immobilisation mechanism has both benefits and drawbacks. 

After the Bride [in the Large Glass] make a picture of shadows cast from objects, [cast] first on a plane and [then] upon a surface with such and such a curvature [and] thirdly upon several transparent surfaces. One can thereby obtain a hypo-physical analysis of successive transformation... 

Neutron activation analysis (NAA), based on the interaction of the object material with fast neutrons, has been used in the identification and determination of the content of elements present in pigments, coins and alloys, stone, glass, and pottery [26]. Multi-elemental analysis (about 20 elements) can be performed on small samples off less than 5 mg, with sensitivities in the ppm range. The requirement of a nuclear reactor, the handling of radioactive materials, and the time-consuming procedures required for preparing the samples are the main drawbacks of this technique. 

The NIR region is of great interest for pharmaceutical applications. NIRS is fast, nondestructive, and cost effective. Samples require no preparation and can be measured as such, intact and available for further analysis. NIRS can be performed in-, on-, and offline. Also, glass fiber optics can be used to perform remote analysis, thus bringing radiation directly to the sample. Many more advantages can be cited when considering the practical use of NIR in a pharmaceutical process, depending on the particular objective. 

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