reported methods, but which are expensive and time-consuming. Thus, it is necessary to develop generic procedures to make fast, cost-effective, and accurate detection possible. Fortunately, an evaporation preparative step has been used as a valuable way to
There is considerable interest in performing volatilisation and evaporation measurements by thermogravimetry. A quick and
simple method for determining vapour pressure using a conventional thermobalance and standard sample holders has been developed.
These yield meaningful thermodynamic parameters such as the enthalpies of sublimation and vaporisation. Under favourable conditions
the melting temperature and enthalpy of fusion of such compounds can be obtained. This technique has been used for the study
of dyes, UV absorbers and plasticisers. The use of modulated- temperature programs for such work is also described.
Evaporation and compositional changes of the liquids above the melting point of LiInSe2 crystals have been characterized quantitatively by using special techniques of a rapid thermal analysis and differential
dissolution. The occurrence of a liquid immiscible region in the Li2Se-rich side of the Li2Se-In2Se3 diagram and incongruent evaporation with the preferential evaporation of In2Se3 rising markedly above boiling point were determined from the peaks on the thermal curves and from precise control over the
composition of the vapour and residual solid as a function of temperature. It was shown that both the processes could be the
sources of nonstoichiometry and inhomogeneity of the LiInSe2 crystals.
The evaporation of benzene, cyclohexane, n-heptane, toluene, 2-xylene, 3-xylene and 4-xylene was studied in H2, He, N2 or CO2 as purge gases for control of the introduced methods of evaluation and the sensitivity limits of TG measurements. Ii as a function of (1−α) and the following equation proved very suitable for a quantitative comparison of 28 independent and
different TG measurements and for a very sensitive characterization of the thermal processes, even within an energy level
difference of 3 kJ mol−1, in spite of the known great inconsistency in the formal kinetic parameters:
The purge gases definitely influence the evaporation. The influence on the average vapour pressure is an exponential function
of the product of the molecular mass and the boiling temperature.
With regard to the number of factors in the TG measurement, and the great sensitivity of Ii and the above function, it can be supposed that these equations exhibit some multivariate regression character, besides their
natural parameter content.
The evaluation methods introduced help to extend the application of TG.
TNAZ (1,3,3-trinitroazetidine) is a relatively new, powerful, steam castable, strained ring explosive. Owing these characteristics
it is of considerable interest to the energetic material community. A relatively high vapour pressure, volume contraction
and formation of shrinkage cavities in the solidification of its melt may be considered as some of its disadvantages. The
kinetics and heats of TNAZ sublimation and evaporation were studied by the non-isothermal and isothermal thermogravimetry
method. The activation energy of 94-102 kJ mol-1 was found for TNAZ sublimation, while the activation energy of 60-81 kJ mol-1 was found for TNAZ evaporation. The enthalpy of TNAZ sublimation at the melting temperature was found to be 95 kJ mol-1, and the enthalpy of TNAZ evaporation equals 66 kJ mol-1.
Main characteristics of gel beads: sample, value of the slope ( B ), ratio calculated ( F ) of B values, enthalpy of evaporation ΔH/Jg −1 , fraction of area 1 (Xa1), heat flow at 35 °C relative to alginate solution (100 × HF / HFa ), fraction of
Bavi , A. , Kashkuli , H. A. , Boroomand , S. , Naseri , A. , Albaji , M. ( 2009 ) Evaporation losses from sprinkler irrigation systems under various operating conditions . Journal of Applied Sciences 9 ( 3 ): 597 – 600
The nuclear energy cycle requires the recycling of nuclear fuel, water, chemical reagents, and the volume reduction of radioactive
liquid wastes. A fundamental technique for continuous recovery of water using a thin-film evaporator was examined. Appropriate
recovery measurements were: an evaporator heat temperature of 323 K, a feed rate of 0.23 cm3s−1, a vacuum pressure of 15 mmHg (2 kPa), and impeller rotational speeds of 500–600 rpm (min−1). The concentration of trace technetium and rhenium in aqueous solutions was also studied. A decontamination factor of 105 for rhenium was obtained.
In radiochemical analysis, the storage of a tracer solution is an important issue to bear in mind. The evaporation of the tracer solution depends on the type of container used for storing. In this paper the evaporation rate in four kinds of containers, i.e., flame-sealed glass ampoule, sealed glass flask, flame-sealed polyethylene ampoule and screw glass vial was studied. It is concluded that the evaporation rate depends on the system of closing.