[en] The geologic sequestration of CO₂ seems to be one of the most relevant strategy for the long term reduction of the atmospheric releases of this greenhouse gas. Indeed, CO₂ can be stored in geologic formations in different ways. The solution which appears as the most stable is to make react fluids rich in CO₂ with rocks minerals (or organic matter) of the surrounding geological formations and to produce a new carbonated solid matrix. The kinetics implied in the mineralization of CO₂ have been studied. In the first part of this work is described the mechanistic aspects of the precipitation reaction of the calcite by a kinetic approach allowing to precisely obtain the velocities and the kinetic constants of the reactions as well as the data on the reactional mechanisms in making the temperature range between 5 and 70 C, as well as the composition of the solution (sur-saturation degree and inhibitor presence: Mg²⁺ and SO₄^2-). The results have shown that the temperature role is not limited to a simple catalyst effect but that the kinetic mechanisms changes, that the temperature induces, determine the Mg quantities which can be incorporated into the calcite. By extension to this study, a global empirical law describing the variation of the precipitation rate in terms of the carbonate concentration and of the different physico-chemical parameters influencing the reaction of the calcite formation (PCO₂, salinity, temperature, inhibitors, organic matter) has been established. It is appeared that the temperature can make the precipitation rate increase but only in the conditions of important imbalance when PCO₂ has an equal influence near and far from the equilibrium in solutions however completely buffered. In the second part, the study has dealt with the movements of supercritical fluids inside a calcitic solid matrix. It has been shown that CO₂ supercritical bubbles trapped into fluid inclusions contained in a calcite polycrystalline matrix could circulate until the crystal surface. These movements can occur through the grain boundaries of the crystals or the microstructures at a velocity ten times superior to the crystalline diffusion in conditions of standard temperature and pressure. Moreover, it has been shown that this phenomenon affects significantly the surface properties of the calcite and has to be taken into account during the predictive modelling of the reactivity and transport of the fluids in the storage medium. (O.M.)

[en] Multi-fragments production in intermediate-energy heavy ion collisions is the most important deexcitation process for hot nuclei produced in small impact-parameter collisions (central collisions). The study of the 60 A.MeV Kr+Au system, performed at GANIL with a 4π and low threshold experimental setup including the fragments and light charged particles multidetectors DELF, XYZt, MUR and TONNEAU associated with 6 solid state detectors, has allowed to measure the global characteristics of dissipative reactions leading to a large amount (up to 6) of fragments with charge greater than 5. The events analysis has been performed by using global variables and has shown that there was the formation of a equilibrated composite system when one looked at kinematical observables (velocities) in the center-of-mass frame. The use of two models, one corresponding to multifragmentation, the other to sequential binary fission, has allowed to conclude for the existence of a simultaneous breakup of the composite system (multifragmentation). Last, no effect related to nuclear matter compressibility (compression/expansion stage) has been found for the most important part of the fragments (charge greater than 10). (orig.)

[en] In this thesis the experimental determination of the strong coupling constant by means of the transverse-energy spectra in e⁺p→e^'++jet+X at √(s)∼300 GeV is described. A value of α_S(M_Z)=0.1212±0.0013(stat.)_-0.0031^+0.023(syst.)_-0.0027^+0.0027(th.) is obtained. (HSI)

[en] It is necessary to design a system that is able to detect the presence of the radioactive source nickel-63, located within the electron capture detector gc- 2010 through the use of Arduino technology, presence sensors and motion This in turn It must be interfaced with a system of tracking and tracing , so collectively be mounted inside the mobile laboratory for research and technological development of systems and equipment for measuring radiation , gases and particles. The program has a structure reading sensors, processing the acquired data and execution of an action if necessary. The system does this by receiving data autonomously, the data is processed and at the end, determines whether the source is in normal operating conditions, if subjected to movements that may cause undesired operation if being handled, or has it has been extracted. (Author)

[en] We use the HIPSE (Heavy-Ion Phase-Space Exploration) Model to discuss the origin of the bi-modality in charge asymmetry observed in nuclear reactions around the Fermi energy. We show that it may be related to the important angular momentum (spin) transferred into the quasi-projectile before secondary decay. As the spin overcomes the critical value, a sudden opening of decay channels is induced and leads to a bimodal distribution for the charge asymmetry. In the model, it is not assigned to a liquid-gas phase transition but to specific instabilities in nuclei with high spin. Therefore, we propose to use these reactions to study instabilities in rotating nuclear droplets. (authors)

[en] It is carried out this investigation with the purpose of determining the effects of steam haulage and of two drying methods in extracted pectin of orange shell, using the residuals of the machine processor of the Caldas region, that it uses the system In Line in the obtaining of the juice for the effect. The essential oils were eliminated the pericarp with haulage of steam, the pectin was extracted with solution to 50% of citric acid and hexametaphosphate of sodium to 0.2%. For shell weight the extraction temperature was of 80 applied during one hour and the pH of 3.4. The pectin was characterized extracted by means of determinations of humidity, ashy, nitrogen, methoxyl percentage, anhidrogalacturonic acid, pH, and acidity. Their behavior is also evaluated by means of determinations that are carried out to the gel with them prepared as its hardness, time and low temperature. They use a totally aleatory statistical design in factorial arrangement 3x2, three treatments: T1 flavedo and albedo with haulage of steam, T2 albedo with steam haulage and T3 albedo without steam haulage and two drying methods, with hot air and with microwaves. The results were analyzed by means of ANDEVA and tests of comparison of Tuckey and Scheff at a level of probability of 95%. They concluded that the steam haulage doesn't have significant influence in the characteristics of the obtained product while, the drying for microwaves influenced significantly in a positive way in the characteristics of the extracted pectin

[en] A meso porous silica molecular sieve was synthesized starting from a neutral polyethylene oxide-based surfactant and sodium silicate solutions by means of a synthesis mechanism not established before for this kind of surfactant, in which sodium intervenes as polymerization agent and at the same time it can act as mediator species M+ in the interaction of the surfactant with silica, presenting in this case besides the neutral meso porous formation route Sa S + route. The conditions of mixing of the surfactant and the sodium silicate solution, around the pH corresponding to the isoelectric point of the silica (pH around 2-3) allow the formation of a transparent homogeneous solution, that makes possible an interaction between the organic and inorganic species before beginning the polycondensation of the silica. The later polymerization of the silica orientated by the surfactant is given by means of an increase in the pH value. The porosity characteristics of the material obtained in this synthesis depend markedly on the polycondensation pH and temperature, the sodium concentration, the molar surfactant/Si ratio, the aging time of the meso porous material in contact with the mother solution and the calcination temperature and time. Polymerization pH values above 5.5 can produce meso porous structures, depending on the values for the other synthesis parameters. In general, relatively high polymerization temperatures (25-50 ), the presence of salts such as NaCl, molar surfactant/Si ratios larger than 0.22 and long aging times increase the meso porous characteristics

No abstract available

[en] The activity of the ligninolytic enzymes, lignin peroxidase (LiP), manganese peroxidase (MnP) and Laccase, in submerged cultures of Phanerochaete chrysosporium, with limited amounts of carbon and nitrogen, were affected by the addition of Mn+2. In cultures with o and 1,25 ppm of Mn+2, only the lip was detected and its higher activity level was observed in the cultures with 1.25 ppm of Mn+2. The cultures with 40 ppm of Mn+2 showed activities of lip, MnP and Laccase. The presence of the three enzymes in the same culture had not been reported and it is of great importance because is shows that the fungus and its lignolitic machinery can act sequentially

[en] Soils play an important role in the study and prevention of the climatic change, because they can be source and sink of carbon. Forest fires that are becoming more frequent, affect physical, chemical and microbiological properties of soils. In recent years the necessity to protect burnt soils from degradation has allowed to find alternative practices to reclaim soil organic matter (SOM) content and functions. (Author)