Studija o katalitickoi oksidaciji aldehida u anhidride masnih kiselina

U literaturi nisu nađeni podaci da bi anhidridi viših masnih kiselina bili stvarno pripravljeni direktnom oksidacijom odgovarajućih aldehida s kisikom ili zrakom u tekućoj fazi u prisutnosti katalizatora. Da bi se ispitala upotrebljivost ove reakcije za dobivanje viših anhidrida, izvršeni su pokusioksidacije n-butanala i 2-etilheksanala. Tom oksidacijom dobiceni u dobrom iskorištenju anhidriri n-maslačne odn. 2-etil-heksan-kiseline. Ispitivano je djelovanje raznih katalizatora na iskorištenje anhidrida u kao najbolji je utvrđena smjesa soli kobalta i bakra, odnosno molibdena i bakra

Studija o katalitickoi oksidaciji aldehida u anhidride masnih kiselina

U literaturi nisu nađeni podaci da bi anhidridi viših masnih kiselina bili stvarno pripravljeni direktnom oksidacijom odgovarajućih aldehida s kisikom ili zrakom u tekućoj fazi u prisutnosti katalizatora. Da bi se ispitala upotrebljivost ove reakcije za dobivanje viših anhidrida, izvršeni su pokusioksidacije n-butanala i 2-etilheksanala. Tom oksidacijom dobiceni u dobrom iskorištenju anhidriri n-maslačne odn. 2-etil-heksan-kiseline. Ispitivano je djelovanje raznih katalizatora na iskorištenje anhidrida u kao najbolji je utvrđena smjesa soli kobalta i bakra, odnosno molibdena i bakra

Characterization of breast tissues in density and effective atomic number basis via spectral X-ray computed tomography

Differentiation of breast tissues is challenging in X-ray imaging because tissues might share similar or even the same linear attenuation coefficients $\mu$. Spectral computed tomography (CT) allows for more quantitative characterization in terms of tissue density and effective atomic number by exploiting the energy dependence of $\mu$. In this work, 5 mastectomy samples and a phantom with inserts mimicking breast soft tissues were evaluated in a retrospective study. The samples were imaged at three monochromatic energy levels in the range of 24 - 38 keV at 5 mGy per scan using a propagation-based phase-contrast setup at SYRMEP beamline at the Italian national synchrotron Elettra. A custom-made algorithm incorporating CT reconstructions of an arbitrary number of spectral energy channels was developed to extract the density and effective atomic number of adipose, fibro-glandular, pure glandular, tumor, and skin from regions selected by a radiologist. Preliminary results suggest that, via spectral CT, it is possible to enhance tissue differentiation. It was found that adipose, fibro-glandular and tumorous tissues have average effective atomic numbers (5.94 $\pm$ 0.09, 7.03 $\pm$ 0.012, and 7.40 $\pm$ 0.10) and densities (0.90 $\pm$ 0.02, 0.96 $\pm$ 0.02, and 1.07 $\pm$ 0.03 g/cm$^{3}$) and can be better distinguished if both quantitative values are observed together.Comment: 26 pages, 7 figures, submitted to Physics in Medicine and Biolog

Some remarks on the homogenization of immiscible incompressible two-phase flow in double porosity media

ACLInternational audienc

Existence for a global pressure formulation of water-gas flow in porous media

We consider a model of water-gas flow in porous media with an incompressible water phase and a compressible gas phase. Such models appear in gas migration through engineered and geological barriers for a deep repository for radioactive waste. The main feature of this model is the introduction of a new global pressure and it is fully equivalent to the original equations. The system is written in a fractional flow formulation as a degenerate parabolic system with the global pressure and the saturation potential as the main unknowns. The major difficulties related to this model are in the nonlinear degenerate structure of the equations, as well as in the coupling in the system. Under some realistic assumptions on the data, including unbounded capillary pressure function and non-homogeneous boundary conditions, we prove the existence of weak solutions of the system. Furthermore, it is shown that the weak solution has certain desired properties, such as positivity of the saturation. The result is proved with the help of an appropriate regularization and a time discretization of the coupled system. We use suitable test functions to obtain a priori estimates and a compactness result in order to pass to the limit in nonlinear terms