Post-war development of geography in Poland

Ces notes témoignent de la vitalité et du dynamisme de la géographie polonaise d'après-guerre. Les chiffres fournis sont impressionnants, surtout si l'on songe à la rapidité avec laquelle la géographie polonaise est ressuscitée du néant où la guerre l'avait plongée. Aujourd'hui sept universités, sept écoles supérieures d'économique, un grand nombre d'écoles supérieures de pédagogie et d'universités technologiques dispensent un enseignement géographique spécialisé.Comme dans la plupart des démocraties populaires, la géographie physique et la géographie économique font l'objet des plus actives recherches. La géomorphologie est une spécialité polonaise ; et c'est en Pologne que les recherches sur les problèmes du quaternaire et sur la géomorphologie périglaciaire connaissent leur maximum de développement. La géographie économique a été de son côté l'objet de recherches très poussées et originales, notamment dans les questions de régionalisation, problème auquel les organismes gouvernementaux des démocraties populaires attachent une énorme importance.L'auteur note que la géographie polonaise a aussi ses points faibles, particulièrement en géographie des transports, en cartographie, en histoire de la géographie et, surtout, en géographie mathématique.Bref, l'avenir de la géographie polonaise s'annonce brillant

Two component Bose-Hubbard model with higher angular momentum states

We study a Bose-Hubbard Hamiltonian of ultracold two component gas of spinor Chromium atoms. Dipolar interactions of magnetic moments while tuned resonantly by ultralow magnetic field can lead to spin flipping. Due to approximate axial symmetry of individual lattice site, total angular momentum is conserved. Therefore, all changes of the spin are accompanied by the appearance of the angular orbital momentum. This way excited Wannier states with non vanishing angular orbital momentum can be created. Resonant dipolar coupling of the two component Bose gas introduces additional degree of control of the system, and leads to a variety of different stable phases. The phase diagram for small number of particles is discussed.Comment: 4 pages, 2 figure

On the stability of Bose-Fermi mixtures

We consider the stability of a mixture of degenerate Bose and Fermi gases. Even though the bosons effectively repel each other the mixture can still collapse provided the Bose and Fermi gases attract each other strongly enough. For a given number of atoms and the strengths of the interactions between them we find the geometry of a maximally compact trap that supports the stable mixture. We compare a simple analytical estimation for the critical axial frequency of the trap with results based on the numerical solution of hydrodynamic equations for Bose-Fermi mixture.Comment: 4 pages, 3 figure

Free expansion of a Bose-Einstein condensate at the presence of a thermal cloud

We investigate numerically the free-fall expansion of a $^{87}$Rb atoms condensate at nonzero temperatures. The classical field approximation is used to separate the condensate and the thermal cloud during the expansion. We calculate the radial and axial widths of the expanding condensate and find clear evidence that the thermal component changes the dynamics of the condensate. Our results are confronted against the experimental data

Soliton trains in Bose-Fermi mixtures

We theoretically consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases. While we assume the forces between atoms in a pure Bose component to be effectively repulsive, their character can be changed from repulsive to attractive in the presence of fermions provided the Bose and Fermi gases attract each other strongly enough. In such a regime the Bose component becomes a gas of effectively attractive atoms. Hence, generating bright solitons in the bosonic gas is possible. Indeed, after a sudden increase of the strength of attraction between bosons and fermions (realized by using a Feshbach resonance technique or by firm radial squeezing of both samples) soliton trains appear in the Bose-Fermi mixture.Comment: 4 pages, 4 figure

The effect of organic acids as leaching agents for hydrometallurgical recovery of metals from PCBs

The hydrometallurgical treatment, compared to other recycling processes, is of great interest due to its higher efficiency and better economy. In hydrometallurgy, popular agents used in the leaching processes of e-waste include inorganic acids, ammonia, chlorides, thiourea, thiosulphates. Organic acids are also becoming more and more popular. The article presents an overview of possible paths of the metal recovery from e-waste with the use of various organic acids. The results of own research on the leaching of printed circuit boards with the use of organic acids including citric acid, oxalic acid, acetic acid, formic acid, malic acid, lactic acid are also presented

The effect of organic acids as leaching agents for hydrometallurgical recovery of metals from PCBs

The hydrometallurgical treatment, compared to other recycling processes, is of great interest due to its higher efficiency and better economy. In hydrometallurgy, popular agents used in the leaching processes of e-waste include inorganic acids, ammonia, chlorides, thiourea, thiosulphates. Organic acids are also becoming more and more popular. The article presents an overview of possible paths of the metal recovery from e-waste with the use of various organic acids. The results of own research on the leaching of printed circuit boards with the use of organic acids including citric acid, oxalic acid, acetic acid, formic acid, malic acid, lactic acid are also presented