Economic Cycles of Carnot Type

Originally, the Carnot cycle was a theoretical thermodynamic cycle that provided an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system. The first aim of this paper is to introduce and study the economic Carnot cycles concerning Roegenian economics, using our thermodynamic–economic dictionary. These cycles are described in both a Q−P diagram and a E−I diagram. An economic Carnot cycle has a maximum efficiency for a reversible economic “engine”. Three problems together with their solutions clarify the meaning of the economic Carnot cycle, in our context. Then we transform the ideal gas theory into the ideal income theory. The second aim is to analyze the economic Van der Waals equation, showing that the diffeomorphic-invariant information about the Van der Waals surface can be obtained by examining a cuspidal potential.     

Study of the Involvement of <Superscript>8</Superscript>Be and <Superscript>9</Superscript>B Nuclei in the Dissociation of Relativistic <Superscript>10</Superscript>C, <Superscript>10</Superscript>B,and <Superscript>12</Superscript>C Nuclei

The results obtained by estimating the contribution of 8Be and 9B nuclei to the coherent dissociation of ¹⁰C, ¹⁰B, and ¹²C relativistic nuclei in nuclear track emulsions (“white” stars) are presented. The selection of white stars accompanied by 9B leads to a distinct peak appearing in the distribution of the excitation energy of 2α2p ensembles and having a maximum at 4.1 ± 0.3 MeV. A 8Be nucleus manifests itself in the coherent-dissociation reaction ¹⁰B → ²He + H with a probability of (25 ± 5)%, (14 ± 3)% of it being due to 9B decays. The ratio of the branching fractions of the ⁹B + n and ⁹Be + p mirror channels is estimated at 6 ± 1. An analysis of the relativistic dissociation of ¹²C nuclei in a nuclear track emulsion revealed nine 3α events corresponding to the Hoyle state.     

Conformational changes of strong polycations in the presence of divalent counterions and their influence upon the flocculation efficiency

The interaction between strong polycations, which possess the ammonium quaternary centers attached to an acrylic macromolecular chain derived from poly(N,N-dimethylaminoethyl methacrylate) (polycations Q_x), and divalent counterions was investigated by viscometry and turbidimetry. Conformational changes of polycations were influenced by the polycation charge density, counterion nature (SO₄²⁻ or S₂O₈²⁻) and concentration. The morphology of the polycation layers deposited onto silicon wafers has been studied by tapping mode atomic force microscopy, a strong influence of the polycation and ammonium persulfate concentration on the surface topography being observed. The optimum flocculation concentration of polycation decreased and the flocculation window increased in the presence of S₂O₈²⁻, in the destabilization of kaolin model dispersion. Removal of Congo Red from aqueous solution by the complex system formed between polycations and divalent counterions was also investigated. The behavior of polycations Q_x in separation processes was compared with that of one polycation containing 95 mol% N,N-dimethyl-2-hydroxypropyleneammonium chloride units in the backbone (PCA₅).     

BaTiO3 and PbTiO3 perovskite as catalysts for methane combustion

Unsupported and γ-Al₂O₃-supported Ba and Pb titanate catalysts were prepared, characterized and studied in the combustion of methane, as a test reaction for VOCs’ catalytic combustion. They present good catalytic activities, and after dispersion (5%) on γ-Al₂O₃ the specific activity of the supported perovskite phase increased 25 and 30 times, respectively, compared with the unsupported samples. PbTiO₃/γ-Al₂O₃ shows the best catalytic properties among the tested samples.     

Supramolecular Systems from Natural Polymers and Maleic Polyelectrolytes

Summary: The formation of polyelectrolyte complexes by interaction between chitosan and maleic acid copolymers as strong/weak dibasic polyanions was investigated. The interaction between the sodium salt of maleic acid copolymers with styrene or vinyl acetate and the chitosan hydrochloride in aqueous solution was followed by potentiometric, conductometric and turbidimetric titration. The effect of the added low molecular salt on the complex formation was also investigated. The precipitated complexes were analyzed by FTIR spectroscopy and TG analysis. Preliminary layer-by-layer deposition experiments were performed to obtain thin films.     

Polysilanes. A New Route Toward High Performance EL Devices

The discovery of a remarkable class of plastics that can conduct electricity has opened a new era of plastics science and technology that has just been recognized by the award of the 2000 Nobel prize for chemistry. They can be used to make a wide range of electronic devices such as transistors, light-emitting diodes, solar cells and even lasers, through much simpler manufacture than conventional inorganic materials, increasing flexibility, reducing cost, and opening up new markets. Polysilanes are subject of an intensive research work aiming to various optoelectronic applications. Through this work the chemical structure of polydiphenylsilane was modified to obtain both solubility in common solvents and to induce new properties by attaching of various organic segments.     

Biotinylated chitosan-based SPIONs with potential in blood-contacting applications

Haemocompatible biotinylated superparamagnetic nanoparticles (size range 300–700 nm) have been obtained by coating magnetite through ionic gelation with a mixture of chitosan and sodium tripolyphosphate, followed by subsequent functionalisation with biotin. The evaluations of their magnetic properties together with haemocompatibility tests have shown that these nanoparticles exhibit the prerequisite behaviour for use in magnetic field–assisted separations within biological systems.     

Influence of the heat treatment conditions on the formation of CuFe2O4 from mechanical milled precursors oxides

Stoichiometric mixture of CuO and ??-Fe₂O₃ milled in air up to 30?h was subjected to different heat treatments. The evolution of the heat treated milled powders was investigated by X-ray diffraction (XRD). The CuFe₂O₄ was partially obtained by milling, the material consisting in a mixture of phases. By applying different heat treatments in air and in vacuum, for 2?C6?h, in 500?C800?°C temperature range the phases composition of the milled samples is changed. A heat treatment at 500?°C in vacuum favours the formation of delafossite (CuFeO₂) and tenorite (CuO) phases. If the same heat treatment is made in air, the CuFe₂O₄ phase formation with a cubic structure is favoured. Differential scanning calorimetry (DSC) investigation realised in Ar atmosphere revealed two large exothermic peaks. The first one is associated with the formation of the delafossite and tenorite phases and the second one with the formation of CuFe₂O₄. The XRD patterns of the samples subjected to the DSC measurements present maxima corresponding to the delafossite and cuprospinel (CuFe₂O₄) phases. For the heat treatment at 600?°C in air the phases present in the sample are the same as for the annealing performed at 500?°C: CuFe₂O₄, ??-Fe₂O₃ and CuO. The heat treatment in air at 800?°C leads to the complete reaction between the different phases and the formation of CuFe₂O₄ phase in whole the sample volume. The CuFe₂O₄ ferrite crystallises after this heat treatment in two crystal systems: cubic and tetragonal.     

Deposition of continuous nickel shells on polymer microspheres

Anisotropic conductive adhesives (ACAs) are widely used as interconnect materials in the manufacturing of LCD screens. To be integrated in a broader range of applications, several technical and economical issues still need to be addressed. Encapsulating the polymer particles within continuous, compact, and adhering metallic conductive shells is one of these challenges. This work describes a method for depositing nickel layers with different thickness (30-120nm) onto monosized polymer particles. The novelty of the approach consists in modifying the surface of polymer particles with linear polymeric amines. We show that by increasing amine chain length the structure and adhesion of deposited nickel shell are significantly improved. The effect of key parameters of the electroless Ni plating are discussed and illustrated.