Authors:Ernő Tyihák, Ágnes Móricz, Judit Mátyási, Péter Ott, and József Balla
The present and more recent observations suggest that the ozone is an indispensable, endogenous molecule form, and so it can be detected and measured practically in all biological systems. There are already different indirect and direct methods for the detection and measurement of this small molecule. The endogenous formation of ozone in the biological world may open a totally new horizon, e.g., in the topics of disease resistance and cell proliferation. Special efforts and more and more efficient methods are needed for observing the endogenous reactions and functions of this very reactive key molecule.
Authors:J. Delben, P. Candelorio, F. de Oliveira, T. Spontoni, Angela Delben, M. Coelho, and L. Andrade
Petroleum natural gas (PNG) reserves will last even when the oil reserves are exhausted, requiring the development of technologies
for PNG storage. Activated charcoal is the best material for such a purpose. Under vacuum samples of aroeira (Astronium Urundeuva)
underwent pyrolysis in diverse conditions. The samples were characterized by thermal analysis, scanning electronic microscopy
and infrared spectroscopy. When the pyrolysis temperature increased, mechanical anisotropy resistance tended to disappear.
The pyrolysis became complete only at high temperatures and using a long time of treatment.
Crystallization of fat droplets in complex emulsions, which differed only by the initial structure of proteins, was studied by differential scanning calorimetry, before and after application of a whipping process. Upon cooling at 5 or 1°C min–1, the temperature needed to initiate fat crystallization was lower, and one more distinguishable crystallization peak was detected in emulsions containing caseins, in comparison with the emulsion containing pure whey proteins. Furthermore, the whipping process was accompanied by more protein depletion from the fat droplet surface, less resistance to coalescence, and a lower supercooling effect in the emulsion based on pure whey proteins.
Authors:Lisardo Núñez Regueira, M. Núñez, M. Villanueva, and B. Rial
The influence of agents originated in a municipal landfill on the thermal degradation of a polymeric system composed of a
diglycidyl ether of bisphenol A (n=0) and 1,2-diaminecyclohexane was studied by thermogravimetric analysis (TG) in order to obtain the lifetime of this material
before and after being attacked. The different data obtained were analyzed to check the resistance of these materials to chemical
attack and the possibility of their use as coating materials in plants where those reagents were present. At the optimum temperature
of service for this material, 373.16 K, the lifetimes obtained from the experimental results were 2633 years and 2135 years,
Summary In this work the kinetics of the high-temperature oxidation of the powder amorphous carbon and bulk single-wall carbon nanotubes is studied. The thermal degradation of the sample is measured by differential scanning calorimetry using the continuous heating regime up to 1273 K. Also, the oxidation resistance of the samples is evaluated by the mass loss in a thermogravimetric analyzer. Both flowing and static oxygen and dry-air atmospheres are used. The specific role of the external diffusivity of the reagent gas is analyzed. The kinetics of the chemical reaction is specified using the Kissinger, Coats and Redfern methods.
Summary Polymers have a great interest for the study and design of new materials. Among these materials are epoxy resins, that have good properties, such as low shrinkage during cure, good adhesion, high water and chemical resistance, etc. They have also fast and easy cure in a broad range of temperatures. TTT diagrams are very helpful to design new epoxy materials as they allow the search for very important final properties, such as thermal stability, conversion or glass transition temperature of a material cured through a selected curing cycle. In this work the dependence of the thermal stability on the selected curing cycle for a DGEBA/1,2 DCH system was studied.
The radioactive boric acid wastes generated from the nuclear power plants have been solidified with cement. One of the properties required for solidified radioactive wastes is resistance to leaching. The leachability of137Cs from solidified waste specimens prepared by various formulation has been studied according to the proposed ANS 16.1 Standard Leach Test. For the evaluation of radiological safety in the solidified radioactive waste disposal, the leachability indices have been determined from the leaching test data. The results have turned out to be 5.97–7.60, depending on formulation and solidifying matrix.
Authors:C. Tamain, A. Özgümüs, N. Dacheux, F. Garrido, L. Thomé, C. Corbel, and E. Mendès
The effect of external irradiation on β-thorium phosphate-diphosphate (tetravalent actini des bearing storage matrix) and
the influence on its dissolution in aqueous media were studied. Highly energetic heavy ions were used to get the amorphization
of the crystalline structure of the ceramic. The ex-situ dissolution expenments showed an increase of the dissolution versus
amorphous fraction in several pH and temperature conditions. The in-situ dissolution experiments highlighted the primordial
importance of radiolytic produced free radical species. From these results, the ceramic presents a good resistance to aqueous
alteration even in amorphous state.
This review focuses on dissolution/reaction systems capable of treating uranium metal waste to remove its pyrophoric properties.
The primary emphasis is the review of literature describing analytical and production-scale dissolution methods applied to
either uranium metal or uranium alloys. A brief summary of uranium's corrosion behavior is included since the corrosion resistance
of metals and alloys affects their dissolution behavior. Based on this review, dissolution systems were recommended for subsequent
screening studies designed to identify the best system to treat depleted uranium metal wastes at Lawrence Livermore National
Authors:C. Tonin, A. Aluigi, M. Bianchetto Songia, C. D'Arrigo, M. Mormino, and C. Vineis
In the wool textile industry, several processes serve to improve the commercial properties of the fibres such as fineness,
softness, length, strength and lustrous. For example, wool is chemically treated with reductive agents then stretched and
set. This leads to modifications of the original protein structure causing changes in thermal behaviour, dyeing, colouristic
and wet resistance properties. A multidisciplinary approach was used to investigate treated and untreated wools, with the
aim of exploiting the nature of the structural changes. SEM and TEM revealed changes on the cuticle and cortical cell morphology;
structure modification were studied by FT-IR and DSC.