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higher resistance to rapid crack propagation, indicating a higher resistance to brittle fracture [ 3 ]. The structural evolution during the solidification of austenitic stainless steels plays a crucial role in the materials’ properties [ 4 ]. The

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associated with the HAZ, not with the weld metal [ 1 ]. One of the aspects that play an important role is the solidification rate. The cooling rate is normally not uniform during the solidification of the steel, e.g., in continuous casting or welding

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Introduction The solidification pattern of cast iron is influenced by a number of factors including the melting conditions, chemistry of the base iron, inoculation practice and solidification conditions. When solidification is

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problems involving social, economic, political, environmental, and health issues. One of the main challenges for Brazilian industries has been the management of their industrial waste in accordance to environmental law requirements. Solidification

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mass of cetane is in Table 1 , too. Melting and solidification of bulk- and confined-cetane forms was studied by the DSC. Two power compensation instruments were used, namely Perkin-Elmer DSC7 with the intracooler filled with the ethylene

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Abstract  

The suitability of Syrian Portland cement for disposal of solidified low-level radioactive waste was assessed by measuring the leaching rate of 134Cs. In ordinary cement concrete, a leaching rate of 1.309 × 10−3 g/cm2 per day was measured. Mixing this concrete with microsilica reduced significantly the leaching rate to 3.106 × 10−4 g/cm2 per day for 1% mixing, and to 9.645 × 10−5 g/cm2 per day for 3% mixing. It was also found that the application of a latex paint reduced these leaching rates by about 10%. These results, along with mechanical strength tests (under radiation exposure, high temperature, long water immersion and freeze–thaw cycling) indicate that Syrian Portland cement is suited for the disposal of low-level radioactive waste.

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information about the composition of the alloy [ 7 , 8 ], the latent heat of solidification [ 9 , 10 ], the evolution of the fraction solid [ 7 , 11 ], the types of phases that solidify [ 7 ], and even dendrite coherency [ 12 ]. There are also many other

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Structure formation during polymerization of polyacrylamide and gelatinization of gelatine in aqueous solutions are described. In both cases dissipative dynamic structures occur in the solutions due to convective flows and manifest in macroscopically visible structure patterns after solidification. Adverse vertical temperature gradients of maximal 2‡C for polymer solutions and 1‡C for gelatine solutions are assumed to be responsible for the instability of the systems and thus for their dynamic behaviour.

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Solidification of molten zinc chloride

Experimental and theoretical studies

Journal of Thermal Analysis and Calorimetry
Authors: M. Rodová, M. Liška, K. Nitsch, and Z. Kožíšek

Abstract  

Solidification of molten zinc chloride was studied both experimentally and theoretically. By isothermal thermal analysis the time needed for the melt to crystallize at a given temperature ranging between 453 and 553 K was determined and the data obtained were compared with those of a calculated TTT curve. The extremum coordinates (temperature T N, time t N) of the curve, critical cooling rate v CR, interfacial energy σ, and an additional parameter of kinetics barrier for nucleation ɛ were determined as T N=508 K, t N=7.29 s, v CR=11.38 K s−1, σ=0.11956 J m−2 and ɛ=0.5712. By non-isothermal method the critical cooling rate of glass formation was determined as 1.25 K s−1.

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Abstract  

The stabilization/solidification of tannery waste containing chromium was studied as an option for its treatment and final disposal, by using a Portland cement type II and two different commercial bentonites (sodium and organophilic) as additives. Different compositions were evaluated by compressive strength analysis, porosity measurement, leaching tests and thermal analysis. The effect on the compressive strength is directly related to the resulting effect of the components present in the original paste on the hydration degree of the cement, which can be evaluated by thermogravimetric analysis from the dehydration steps of tobermorite and ettringite phases of the pastes. The results show that this process is suitable for the treatment of the tanning waste and that the best conditions of stabilization are obtained when both additives are used.

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