Lezioni di scienza delle finanze

- Indice #11- Caratteri degli studi finanziari #19- Effetti economici delle imposte: nozioni generali #93- La dottrina del reddito #159- Imposte sui trasferimenti e sui consumi nei loro aspetti teorici e pratici #231- Le finanze locali #263- Considerazioni generali sulla finanza straordinaria #27

Elementi di economia generale e corporativa con cenni di statistica e di finanza secondo i nuovi programmi per gli Istituti tecnici commerciali superiori

- Regimi economici #7- Statitistica #143- Il bilancio dello Stato #163- Moneta e credito #231- Politica economica #319- Indice #34

Preferential grafting of alkoxysilane coupling agents on the hydrophobic portion of the surface of micelle-templated silica

Silica having a regular mesoporous structure induced by micelle templating (MTS) was functionalised with n-propyltrimethoxysilane under anhydrous conditions. Support modification was characterised by various methods (X-ray diffraction, FTIR spectroscopy, thermogravimetry, nitrogen adsorption volumetry, microcalorimetry and FTIR of water adsorption). Functionalisation takes place mainly at the hydrophobic patches of the surface, involving surface siloxane bridges, and occurs through a nucleophilic displacement at the silicon atom by the alkylsiloxane group of the silylating agent. Hydrophilic patches of the surface, consisting of hydrogen-bonded silanol groups, do not constitute, in anhydrous conditions, active sites for the covalent anchorage of the organosilane moieties on the MTS surface

A macrothermodynamic approach to the limit of reversible capillary condensation

International audienceThe threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The non-hysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butanol in MCM-41 silica confirm a 20 % increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justify the disappearing of the hysteresis loop