Semistar ascending chain conditions over polynomial rings

Ricerche di Matematica - Let D be an integral domain. G. Picozza associated to a stable semistar operation $$\star $$ on D,  a semistar operation $$\star _1$$ on the polynomial ring D[X]....     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(OCH3)3?OPCl3 und SP(OCH3)3?SPCl3

The IR- and RAMAN -spectra are reported from OP(OCH₃)₂Cl, OP(OCH₃)Cl₂, SP(OCH₃)Cl, SP(OCH₃)Cl₂. The assignement to the fundamental vibration is given and all Valence-force-constants are calculated. With increasing number of chlorine atoms decrease f P? OCH₃ and f P? Cl. In the contrary, f O? P and f S? P increase. Here the influence of decreasing electro negativity is compensated by the change from an element of the first period of eight elements to an element of the second period.     

Réactivité par voie thermique de RFH

Hydroperfluoroalkanes are well known as being rather inert chemically. Hydroperfluoroalkanes react at high temperature with carbon tetrabromide and carbon tetrachloride to yield bromoperfluoroalkanes and chloroperfluoroalkanes.

Résumé

Les hydroperfluoroalcanes sont connus pour être stables chimiquement. Nous montrons qu'ils réagissent à haute température vis-à-vis de tétrabromure de carbone et de tétrachlorure de carbone pour conduire aux bromoperfluoroalcanes et chloroperfluoroalcanes correspondants.     

Synthesis of substituted 1-trifluoromethyl and 1-perfluoroalkyl-3-(arylamino)prop-2-en-1-one: advances in the mechanism of Combes 2-trifluoromethyl and 2-perfluoroalkyl quinolines synthesis

We report a new synthesis and our study of the mechanism of formation of substituted 1-trifluoromethyl and 1-perfluoroalkyl-3-(phenylamino)prop-2-en-1-one starting from 3-(R-phenoxy)-3-perfluoroalkyl-prop-2-enals and arylamines. Reactivity study of the intermediates confirmed that 3-perfluoroalkyl-N,N′-diphenyl-1,5-diazapentadienes are the synthetic intermediates of the synthesis of 2-perfluoroalkylquinolines. The mechanism of the reaction of 1-trifluoromethyl and 1-perfluoroalkyl-3-(phenylamino)prop-2-en-1-one with POCl₃ was studied. To our knowledge this is the first detection and isolation of N,N′-diaryldiazapentadiene derivatives as intermediates in the Combes F-alkyl substituted quinoline synthesis starting from enaminoketones. Finally, we succeeded isolating and identifying unsymmetrically substituted 2-perfluorolakyldiazapentadiene.     

Supply chain optimization of petroleum organization under uncertainty in market demands and prices

A multi-period stochastic planning model has been developed and implemented for a supply chain network of a petroleum organization operating in an oil producing country under uncertain market conditions. The proposed supply chain network consists of all activities related to crude oil production, processing and distribution. Uncertainties were introduced in market demands and prices. A deterministic optimization model was first developed and tested. The impact of uncertainty on the supply chain was studied by performing a sensitivity analysis in which ±20% deviations were introduced in market demands and prices of different commodities. A stochastic formulation was then proposed, which is based on the two-stage problem with finite number of realizations. The proposed stochastic programming approach proved to be quite effective in developing resilient production plans in light of high degree of uncertainty in market conditions. The anticipated production plans have a considerably lower expected value of perfect information (EVPI). The main conclusion of this study is that for an oil producing country with oil processing capabilities, the impact of economic uncertainties may be tolerated by an appropriate balance between crude exports and processing capacities.     

Identification of the Physical Parameters Used in the Thermo-Hygro-Mechanical Model

This paper describes different methods used to identify a large number of physical parameters of the thermo-hygro-mechanical coupling model. This model is developed on the basis of mechanics of porous media and deals with the prediction of response of a structure submitted to thermal, hygrometric and mechanical loading. The aim of this work is mainly to propose some experimental methods for the determination of physical parameters used previously in the model such as hygrometric parameters (liquid Biot's coefficient b _l , vapour and liquid permeability _v, _l and tangent capillary modulus N _ll). Thermal parameters such as thermal conductivity (), specific heat (C) and the thermo-hydrous expansion coefficient ( _i ^p ) have been identified using some works published previously. The different physical parameters were identified in the case of cement mortar without taking into account the influence of hysteresis.     

Reactivite des perfluorohalogenoalcanes en presence de couples metalliques—II: Formation de perfluoroolefines a partir des perfluoroiodoalcanes dans les solvants aprotiques dissociants, (DMSO,DMF, HMPT)

The action of zinc-copper couples on perfluoroiodoalkanes C₄F₉I, C₆F₁₃I and C₈F₁₇I was studied in DMSO, DMF, or HMPT; a mixture of isomeric perfluoroolefins was obtained. A general mechanism for the action of these metallic couples, involving a perfluorinated organometallic intermediate, is proposed.     

Synthesis of symmetric and dissymetric bisperfluoroalkanesulfonylimides and evaluation of their inhibition on bovine carbonic anhydrase

This study describes a synthesis of symmetric and dissymmetric bis[(perfluoroalkane)‐sulfonyl]imides by the reaction of the sodium salt of perfluoroalkanesulfonamide R_FSO₂NH⁻Na⁺ (R_F = C₄F₉, C₆F₁₃, C₈F₁₇) with hexamethyldisilazane and perfluoroalkanesulfonylfluoride R_FSO₂F (R_F = C₄F₉, C₆F₁₃, C₈F₁₇). They are obtained, in two steps, in moderate overall yield. Moreover, this paper provides a study of their inhibition on bovine carbonic anhydrase. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:542–548, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20452