Emission spectroscopy from optically thick laboratory acetylene samples at high temperature

Recently, a high temperature source has been used to produce high temperature emission spectra of acetylene in the 3 μm spectral range, under Doppler limited resolution, and the complete spectral assignment has been performed using a global rovibrational Hamiltonian [Amyay B, Robert S, Herman M, Fayt A, Raghavendra B, Moudens A et al. Vibration-rotation pattern in acetylene (II): Introduction to Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm. J Chem Phys 2009;131:114301]. The present investigation focuses on the relative emission line intensities which are observed to be affected. The strongest lines intensity may be considerably reduced for high column density acetylene samples, hence affecting the 3:1 ortho:para intensity ratio. A radiative model is developed to take into account the effects generated by the strong opacity of the acetylene samples including self-absorption and absorption of the radiation emitted by the hot environment. The model is used to extract the absolute concentration of the high temperature acetylene samples from the observed relative spectral intensities. The relevance of the procedure for infrared remote sensing in high temperature astrophysical environments, such as circumstellar envelopes of cool carbon rich evolved stars, is discussed.     

Influence of Polymerization Temperature on Reactivity of 1- and 2.Vinyl Naphthalenes

Reactivity ratios relative to the copolymerizations of 1-vinyl naphthalene and 2-vinyl naphthalene with styrene have been determined at different specific temperatures. In the case of the system 1-vinyl naphthalene-styrene, the Arrhenius plot exhibits a curve when the temperature is above -50°C. This is explained by the depropagation contribution, The value of the enthalpy of polymerization calculated by using the Lowry relation is in satisfactory agreement with that obtained from calorimetric determinations. From activation enthalpies and entropies it appears that the selection of the two monomers by the cation is entropically controlled for 2-vinyl naphthalene and enthalpically controlled for 1-vinyl naphthalene.     

Novel chemo-enzymatic access to amphiphilic cyclodextrins

A new class of mono-substituted amphiphilic cyclodextrins was synthesized in a one-step lipase catalysed amidification. Microbial and animal lipases were able to catalyse this reaction. Depending on the acyl donors, various hydrophobic moieties have been grafted on methylated β-cyclodextrin. Azoninyl-methylated-β-cyclodextrin derivatives were also obtained by reaction of acetaldehyde and modified cyclodextrins in presence of dedicated lipase.     

Sur la classification des automorphismes périodiques des C1-algèbres UHF

We obtain a complete classification up to conjugacy and up to outer conjugacy of finite tensor product type automorphisms of UHF C¹-algebras which are periodic of period N (N prime).     

Mechanism of the thickening reaction of polyester resins: Study on models

The thickening reaction of polyester resins is investigated using model compounds, diesters or polyesters of 1,2-propanediol and phthalic acid with dihydroxy or dicarboxy end groups. Soluble magnesium acetylacetonate was found to be an effective thickener, and for the first time it was possible to study a thickening reaction in homogeneous media (THF solutions). The results are compared with those obtained with MgO. The proposed mechanism supposes that the central step consists of the formation and the aggregation of magnesium carboxylates in ionic areas, with entanglement of attached polyester chains. This fits our experimental results better than the hypothesis of coordination of magnesium carboxylates by ester or hydroxyl groups of the chains^2–6 or than the hypothesis of the formation of linear high molecular weight compounds.^7–9     

Preparation de membranes echangeuses de cations par photogreffage d'ethers allyliques du poly (alcool vinylique). Etude de certaines de leurs proprietes—I: Preparation et etude de poly (alcool vinyliques) allyles

A new preparation of poly(vinyl alcohol) partially allylated (PAOV) is reported. The possible existence of crosslinking is explained but, under suitable conditions, it can be avoided. A detailed analysis of the infra red spectrum of PAOV shows that during allylation the structure of the original poly(vinyl alcohol) (PAV) is not changed. The compatibility of various monomers is studied.     

Thermodynamic treatment of nonphysical systems: Formalism and an example (Single-lane traffic)

An effort is made to introduce thermodynamic and statistical thermodynamic methods into the treatment of nonphysical (e.g., social, economic, etc.) systems. Emphasis is placed on the use of theentire thermodynamic framework, not merely entropy. Entropy arises naturally, related in a simple manner to other measurables, but does not occupy a primary position in the theory. However, the maximum entropy formalism is a convenient procedure for deriving the thermodynamic analog framework in which undetermined multipliers are thermodynamic-like variables which summarize the collective behavior of the system. We discuss the analysis of Levine and his coworkers showing that the maximum entropy formalism is the unique algorithm for achieving consistent inference of probabilities. The thermodynamic-like formalism for treating a single lane of vehicular traffic is developed and applied to traffic in which the interaction between cars is chosen to be a particular form of the follow-the-leader type. The equation of state of the traffic, the distributions of velocity and headway, and the various thermodynamic-like parameters, e.g., temperature (collective sensitivity), pressure, etc. are determined for an experimental example (Holland Tunnel). Nearest-neighbor and pair correlation functions for the vehicles are also determined. Many interesting and suggestive results are obtained,