MATHEMATICAL MODELING, AUTOMATION AND CONTROL OF THE BIOCONVERSION OF SORBITOL TO SORBOSE IN THE VITAMIN C PRODUCTION PROCESS I. MATHEMATICAL MODELING

In 1990, the Biotechnology and the Control Systems Groups of IPT started developing a system for the control and automation of fermentation processes, applied to the oxidation of sorbitol to sorbose by the bacteria Gluconobacter oxydans, the microbial step of the vitamin C production process, that was chosen as a case study. Initially, a thirteen-parameter model was fitted to represent the batch operation of the system utilizing a nonlinear regression analysis, the flexible polyhedron method. Based on these results, a model for the continuous process (with the same kinetic equations) was constructed and its optimum operating point obtaine

International conference ICAWA 2016 : extended book of abstract : the AWA project : ecosystem approach to the management of fisheries and the marine environment in West African waters

Dynamics of the coastal arrow of the Barbary Language from 1954 to 2016 Situated on the West African Atlantic coast, at the mouth of the Senegal river delta, the sandy coastal arrow of Langue de Barbarie plays a fundamental role in the stabilization of the north coast of Senegal, and constitutes a natural rampart for the historic island city of Saint-Louis that it defends against the swells and storms of the Atlantic. However, the dynamics of the Langue de Barbarie are still complex and little known, as regards in particular the impact of the swell on the shore and the dynamic response of the latter, the contributions of sand and their redistribution by the swell through coastal drift, longshore sediment transport and its interaction with anthropogenic actions (defense works, breach ...), sedimentary bypass and sedimentary exchanges between the delta of the stream and the delta of the adjacent mouth ... which does not facilitate the forecast of scenarios of geomorphological evolution of this coastal arrow whose socio-economic and environmental stakes are unquestionably strong. The lagoon water level behind the Langue de Barbarie tended to rise considerably during a period of high flooding of the Senegal River, particularly during the rainy season, causing repeated flooding in the town of Saint-Louis and its surroundings. It was during one of these flood cycles that, on the decision of the local authorities, a breach 4 meters wide was opened on the coastal spit in October 2003, with the aim of sparing the historic island of a risk of flooding. The opening of this breach certainly made it possible to lower the water level in Saint-Louis, but reveals in consequence serious problems of management and coastal management. The dramatic enlargement of the breach resulted in the dismantling of the coastal arrow, causing the destruction of houses, infrastructure and settlements that it supports, justifying a dynamic analysis of the Langue de Barbarie

Synergistic Configuration of Diols as Brønsted Bases

As viscous hydroxylic organic compounds, diols are of interest for their functional molecular conformation, which is based on inter- and intramolecular hydrogen (H)-bonds. By utilising steady-state electronic and vibrational spectroscopy, time-resolved fluorescence spectroscopy, and computational analyses, we report the association of the hydroxyl groups of diols via intra- or intermolecular H-bonds to enhance their reactivity as a base. Whereas the formation of an intermolecularly H-bonded dimer is requisite for diols of weak intramolecular H-bond to extract a proton from a model strong photoacid, a well-configured single diol molecule with an optimised intramolecular H-bond is revealed to serve as an effective Brønsted base with increased basicity. This observation highlights the collective role of H-bonding in acid–base reactions, and provides mechanistic backgrounds to understand the reactivity of polyols in the acid-catalysed dehydration for the synthesis of cyclic ethers at the molecular level. (c) 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Studies of isomeric states and limits of particle stability around N=Z=40 using fragmentation reactions

Fragmentation products from a 92Mo beam on a natural nickel target have been used to study structural properties of the very neutron deficient nuclei around N∼Z∼40. We present the first observation of isomeric decays in the Tz=1 systems 3674Kr, 3980 Y and 4184Nb. The isomer in 74Kr is interpreted as the hindered decay from an excited 0+ state, confirming the prediction of prolate/oblate shape coexistence in this nucleus. Transitions from states below an isomer in the N=Z nucleus 4386Tc have also been tentatively identified, making this the heaviest N=Z system for which decays from excited states have been observed. In addition, we have obtained the first conclusive evidence for the existence of the Tz = -1/2 isotopes 3977Y, 4079Zr and 4283Mo. The data for 3977Y is of particular interest in light of the reported instability in the lighter odd-Z, Tz = -1/2 systems 69Br and 73Rb