Hidden mass effect

Unlike the Mie theory, the discrete ordinate approximation assumes that the sample is continuous matrix of points that absorb and scatter. The values for the coefficients obtained from the discrete ordinate approximation will also change and deviate substantially from the Mie coefficients as the particle size becomes large. This has been called the hidden mass effect [42]. 

Schwarz, H. Some Newer Aspects of Mass Spectrometric Ortho Effects. 73, 231-263 (1978). Schwarz, H. Radical Eliminations From Gaseous Cation Radicals Via Multistep Pathways — The Concept of Hidden Hydrogen Rearrangements, 97, 1-31 (1981). 

A microscopic picture for the strongly renormalized quasiparticles has finally emerged for the actinide compounds. The hypothesis of the dual character of the 5f-electrons is translated into a calculational scheme which reproduces both the Fermi surfaces and the effective masses determined by dHvA experiments without adjustable parameter. The method yields also a model for the residual interaction leading to the various instabilities of the normal phase. The next step will be to develop an appropriate Eliashberg-type theory. The dual model approach should also provide insight into the mysterious hidden order phases of U-compormds. 

In polydiacetylene single crystals electroreflectance revealed the weak interband transitions, hidden under the stronger vibronic excitons (2). The data yield the band gap, the exciton binding energy and derive in case of DCHD a surprisingly small effective mass m = 0.05 m (3). Charge transfer excitons too respond to an external... 

The buoyancy effect is most of the time a problem that is misunderstood in the TGA measurement or often hidden by the numerical treatment of the TGA curves. Buoyancy is the upward force exerted on an object when it is immersed, partially or fully, in a fluid (liquid or gas). Its value is equal to the weight of the fluid displaced by the object. In the case of the TGA experiment with a given crucible (the object), this results in an apparent increase of the mass when the sample is heated. The effect is observed on all conventional balances. In fact the term buoyancy includes different parameters the true buoyancy as described before, the convection currents, the gas flow drag effects, the gas velocity effects, the thermomolecular forces, the thermal effects on the balance mechanism. 

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