We characterize the stabilization for some coupled infinite dimensional systems. The proof of the main result uses the methodology
introduced in Ammari and Tucsnak , where the exponential stability for the closed loop problem is reduced to an observability
estimate for the corresponding uncontrolled system combined to a boundedness property of the transfer function of the associated
open loop system and a result in .
Authors:M. Prauchner, V. Pasa, C. Otani, and S. Otani
During the production of pitch-based carbon fibers, oxidative thermal stabilization is an important intermediary step, because
it permits the thermoplastic as-spun fibers to be rendered thermosetting. In the present work, DSC analyses are employed to
assess the stabilization of eucalyptus tar pitch fibers. This is possible due to the pronounced differences noticed between
DSC profiles of green and oxidized fibers, which reflect the changes that the fiber structure undergoes during stabilization.
The effect of itaconic acid (IA) content and heating rate on the stabilization reactions in poly(acrylonitrile-co-itaconic
acid) (P(AN-co-IA)) was investigated by differential scanning calorimetry (DSC) with peak-resolving method. Increasing IA
content was effective in decreasing the initial temperature and the heat evolved, and found to enhance oxidative reactions
to some extent. While, promoting heating rate resulted in a shift of the exotherm to a higher temperature and a more rapid
liberation of heat. The percentage of area of the first exothermic peak increased with increasing heating rate, which would
be attributed to the enhancement of the free radical cyclization reactions.
Authors:Caroline A. Pinto, J. Dweck, J. J. Sansalone, F. K. Cartledge, M. E. Tittlebaum, and P. M. Büchler
Summary This paper presents a study of a cement-based solidification/stabilization process of storm water runoff solid residuals by non-conventional differential thermal analysis (NCDTA). The study was used to investigate the early hydration stages of a type I Portland cement containing the raw residual, two fractions of the residuals (coarse and fine), and two additives (quicklime and sodium bentonite). During these stages the fine fraction of the residuals retards the hydration reactions more than the coarse one, and both fractions have components that are reactive during the hydration process. When sodium bentonite is present in the pastes, the higher the initial cement content of the pastes, the lesser is the reactivity of the residuals. The presence of quicklime, which undergoes simultaneous highly exothermal hydration, accelerates the cement hydration reactions as well as those due to the presence of the residual solids. In these quicklime-containing compositions, the effect of sodium bentonite is similar to that when no quicklime is added, except when the whole residuals are used.
In the present work, a Portland cement blended with calcium carbonate is being used to study the solidification/stabilization
(S/S) of a Brazilian tanning waste arising from leather production. Chromium is the element of greatest concern in this waste,
but the waste also contains a residual organic material. Using thermogravimetry (TG) and derivative thermogravimetry (DTG)
to identify and quantify the main hydrated phases present in the pastes, this paper presents a comparative study between the
effects of Wyoming and Organophilic bentonites (B and OB) on cement hydration. Samples containing combinations of cement, B, OB and waste have been subjected to thermal analysis after different setting times during the first 28 days of the waste S/S
process. Both bentonites affect the cement hydration, with no significant differences in hydration degree after 1 week. This
work shows further examples of the great utility of thermal analysis techniques in the study of very complex systems containing
both crystalline and amorphous mineral materials as well as organics.
Authors:F. Yilmaz Korkmaz, N.B. Tuncel, M. Özer, and N. Yilmaz Tuncel
months of storage at room temperature ( Y ilmaz et. al., 2018 ). Therefore, an effective stabilisation process needs to be employed in order to utilise immature rice grains as food rather than feed. The objective of this study was to investigate the