Numerical analysis and field measurements of the airflow patterns and thermal comfort in an indoor swimming pool: a case study

Public indoor swimming pools are a very popular type of sports facility. They need to ensure good indoor air quality and thermal comfort of the occupants (TCO) while reducing their energy consumption. The objectives of this study are to develop a numerical code, based on the zonal method; to investigate the indoor airflow patterns; and to determine the TCO in the indoor swimming pool. The numerical simulation, performed using the TRNSYS software (version 17), is validated against intensive field measurements, carried out in the public indoor swimming pool located at Bishop’s University (Sherbrooke, Quebec, Canada), of the temperature, velocity, and relative humidity of the air as well as the surface temperature of the walls, ceiling, and floor. The developed code is then used to study the indoor flow patterns and to evaluate the TCO using three indexes: the humidex chart, the predicted mean vote (PMV), and the predicted percentage of dissatisfied (PPD). The results show a hot-humid rather uncomfortable atmosphere is prevailing in the occupied parts of the studied indoor swimming pool. The calculated airflow rates show that, due to the position of the ventilation inlets and outlets, most of the ventilation air circulates in the upper part of the building causing an insufficient air renewal in the occupied parts of the studied indoor swimming pool.     

Enzymatic extract from flowers of Algerian spontaneous Cynara cardunculus: Milk‐clotting properties and use in the manufacture of a Camembert‐type cheese

The aim of this study was to assess the coagulant properties of crude extract from cardoon flowers (CECF) as a replacement for the imported coagulants used in the local Algerian cheese factories. Optimal coagulation activity of the extract was observed at pH 5 and 60 °C with a CaCl₂ concentration of 0.02 M. The electrophoretic pattern revealed that the crude extract contains mainly cardosins A and B. The study of interactions involved in the formation of milk gel coagulated by CECF showed that hydrogen forces, hydrophobic interactions and calcium bridges contributed highly to the formation of milk gel. Camembert‐type cheese obtained by CECF was judged by trained panellists and was found to be in agreement with standard specifications. The present study highlights the possibility of using Algerian CECF as a promising plant coagulant in cheesemaking for the dairy industry.     

Proteolysis and volatile profile in the Algerian traditional Bouhezza cheese made using raw goat’s milk

Bouhezza is an Algerian cheese, which is ripened in a goat-skin bag, called Chekoua. The aim of the study was to determine the protein profiles and aromatics, which contribute to sensory properties of Bouhezza cheese. The chemical composition, proteolysis, and volatile profile have been carried out in cheese made from raw goat milk. The results showed that, the dry matter ranged from 23.07 to 51.95%, the fat-in-dry matter ranged from 10.58 to 31.77%, and the protein ranged from 28.27 to 42.09%. Water-soluble and 12% trichloroacetic acid-soluble nitrogen fractions decreased at the beginning of the ripening process and then they increased until the end of ripening. The reverse phase-high-performance liquid chromatography peptide profiles of the cheese showed the modifications occurred during the ripening process. The volatile compounds showed a diversity of odorous components which contribute to give to the cheese its particular organoleptic. There were 109 compounds identified in Bouhezza cheese. Carboxylic acids, esters, and alcohols were the main classes of the volatile components in the cheese.     

Use of semi-empirical potentials to simulate the Si(1 0 0)-SiO2 interface

The rapid development of ab initio methods makes possible the test of semi-empirical potentials which retain some advantages in the simulation of large systems. Even systems involving oxygen vacancies can be studied with semi-empirical methods. Modelling of the Si(1 0 0)-SiO₂ interface raises some specific problems due to charge transfers and severe simplifications are still necessary.     

New crosslinked polyurethane elastomers with various physical properties from natural rubber derivatives

New hydroxytelechelic cis‐1,4‐oligoisoprenes exhibiting variable values and distributions of the hydroxyl functionality were successfully prepared. The synthesis reactions involved chemical modifications of carbonyl telechelic cis‐1,4‐polyisoprene, which was obtained by controlled degradation of synthetic or natural rubber. These new oligomers were reacted with toluene diisocyanate to elaborate crosslinked polyurethane elastomers. The thermomechanical properties of the prepared polyurethanes were investigated. The results show a strong relationship between the chemical structures and properties. This work mainly shows the potentiality of making new crosslinking polyurethane materials with controlled and various properties from natural rubber, a renewable resource. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Elaboration and properties of renewable polyurethanes based on natural rubber and biodegradable poly(butylene succinate) soft segments

Natural rubber (NR) is a renewable bio‐based polymer, while poly(butylene succinate) (PBS) belongs to the family of biodegradable renewable polymers. In this article, novel polyurethanes (PUs) were prepared using hydroxyl telechelic natural rubber (HTNR) and hydroxyl telechelic poly(butylene succinate) (HTPBS) as soft segments, and using toluene‐2,4‐diisocyanate (TDI) and 1,4‐butanediol (BDO) as hard segment. HTPBS oligomers of = 2000 and 3500 g mol^?1 were synthesized by bulk polycondensation of succinic acid (SA) with BDO. The polyurethane materials were obtained by casting process after solvent evaporation. The influence of the hard segment content and the molecular weight of HTPBS on the materials’ thermo‐mechanical properties were investigated by means of tensile testing, DSC, TGA, and DMTA. The obtained polyurethanes were amorphous with phase separations between hard and soft segments as well as between HTNR and HTPBS segments, and they exhibited good physical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42943.     

Synthesis of well defined amino telechelic cis-1,4-oligoisoprenes from carbonyl telechelic oligomers; first studies of their potentialities as polyurethane or polyurea materials precursors

Carbonyl telechelic cis-1,4-oligoisoprene (CTPI) obtained from high molecular weight polyisoprene through an oxidative chain cleavage reaction have been chemically modified. Thus, new well defined amino telechelic cis-1,4-oligoisoprenes have been obtained in a mass range of 1600-2300 g/mol according to two different pathways. The first approach involved a standard mesylate displacement by sodium azide followed by smooth reduction using triphenylphosphine. The second pathway implied a reductive amination sequence. Primary or secondary amine functions have thus been selectively obtained at both oligomer chain-ends depending on reaction conditions. Peculiar NMR experiments conducted on these functional oligomers confirmed a precise control of functionality during the chemical modification. Moreover, their abilities to react with toluene diisocyanate or bis(succinimidyl)carbonate have been investigated.