On décrit la méthode pour le dosage du hafnium dans des aciers étalons. Cette méthode consiste en une combinaison de l'analyse
par activation neutronique avec un procédé d'extraction par solvant, l'agent d'extraction étant le di (2 ethylhexyl) phosphate.
Enfin, on procède à une extraction en retour dans de l'acide fluorhydrique 2N juste avant la mesure d'activité. La mesure
est faite au moyen d'un détecteur Ge(Li) 60 cc associé à un analyseur 2048 canaux. La méthode d'analyse ainsi décrite permet
une détermination rapide du hafnium avec, une précision de l'ordre de 3 à 4% pour les dosages de routine.
Simultaneous TG (thermogravimetric analysis)-DTA (differential thermal analysis) measures both differential temperatures and
weight changes in a material as a function of temperature or time in a controlled atmosphere. Simultaneous measurement of
these two material properties not only improves productivity but also simplifies interpretation of the results. The complementary
information obtained allows differentiation between endothermic and exothermic events which have no associated weight loss
(e.g. melting and crystallization) and those which involve a weight loss (e.g. degradation). The combined evaluation also
assures identical experimental and sampling conditions for both measurements, thereby eliminating those sources of uncertainty.
This paper briefly describes a new simultaneous TG-DTA instrument with emphasis on how the measurements are made and with
several typical applications
Traditionally, Modulated DSC™ (MDSC®)  has been used to simultaneously measure the heat capacity and heat flow of a sample in a single experiment. As first
proposed by Readinget at. in 1992 , this complex heat capacity signal (Cp*) can be further deconvoluted into components which are in-phase (C′p) or out-of phase (C′p with the imposed temperature modulation. The vector sum of these components, respectively termed the reversing Cp and kinetic Cp, is equal to the aforementioned complex Cp (Cp*).
Recent research has centered around the analysis of these signals and their inclusion into MDSC experiments. For most polymer
systems, the contribution of the kinetic Cp is negligible, except at the melt. This signal does contain a small peak at the Tg of PET, but the significance of this peak is to date not clear. Examples of further applications will be presented and discussed,
as well as the derivation and interpretation of novel MDSC signals.
Modulated DSCTM (MDSC) is a new, patent-pending extension to conventional DSC which provides information about the reversing and nonreversing
characteristics of thermal events, as well as the ability to directly measure heat capacity. This additional information aids
interpretation and allows unique insights into the structure and behaviour of materials., A number of examples of its use