Rethinking complexity and issues of CSR:Appropriation by a Moroccan company

Aucune des perspectives ne conduit à la même vision de la Responsabilité Sociétale de l’Entreprise (RSE). Cet article vise à comprendre les divergences de ce concept et propose de dépasser le clivage de son caractère paradoxal par la prise en compte de la complexité de l’organisation et de l’environnement (à travers une approche systémique). Un état des lieux et une étude de cas sur les pratiques dans le contexte marocain sont présentés. Fondée sur une analyse centrée autour de l’entreprise Cosumar SA et de ses parties prenantes, elle met en exergue la stratégie et les pratiques en matière de responsabilités sociétale d’une entreprise marocaine. Il s’agit de décrire les enjeux auxquels cette entreprise est confrontée, les approches stratégiques mises en œuvre pour y répondre et les moyens accomplis pour atteindre les objectifs fixés en matière sociétale

Mix design, properties and cost analysis of fly ash-based geopolymer foam

This study has investigated the joint effect of several mix parameters on the properties of foam geopolymers. The mix parameters analysed through a laboratory experiment of 54 different mortar mixes were, sodium silicate/sodium hydroxide mass ratio (2.5, 3.5, 4.5), activator/binder mass ratio (0.6, 0.8, 1.0), chemical foaming agent type (hydrogen peroxide (H2O2) and sodium perborate (NaBO3)) and foaming agent mass ratio content (1%, 2%, 3%). Properties, SEM and FTIR analysis and cost analysis are included. The results show that the sodium perborate over performs hydrogen peroxide leading to a lower overall thermal conductibility of foam geopolymers. Mixtures with a low thermal conductivity of around 0.1 W/ (m K) and a compressive strength of around 6 MPa were achieved. The cost analysis show that the foaming agents are responsible for a small percentage of foam geopolymers total cost being that the alkaline activators are responsible for more than 80%

Ensilage des déchets de poisson et essai d'alimentation sur les rats

La présente étude a pour but d’évaluer et de comparer l’ensilage biologique et chimique des déchets de poisson. Le mélange formé par les déchets de poisson Sardina pilchardus et la mélasse à 20% a été inoculé par un ferment lactique composé de Lactobacillus plantarum pour effectuer l’ensilage biologique. L’ensilage chimique a été préparé en ajoutant au mélange de l’acide phosphorique à 2%. Une inhibition ou une élimination des microorganismes pathogènes (Clostridium et Staphylocoques) au niveau des ensilages biologique et chimique a été observée. Cela semble s’expliquer par la diminution du pH. Par ailleurs, une augmentation de l’azote non protéique a été montrée. Ceci est dû à une hydrolyse protéique dans l’ensilage chimique. De ce fait, la valeur nutritionnelle de ce dernier est faible par rapport à l’ensilage biologique. Les essais nutritionnels sur les rats montrent que le suivi du poids corporel et de la prise alimentaire donne un avantage à l’ensilage biologique dans l’alimentation animale

Performance of a fly ash geopolymeric mortar for coating of ordinary portland cement concrete exposed to harsh chemical environments

Premature degradation of ordinary Portland cement (OPC) concrete infrastructures is a current and serious problem with overwhelming costs amounting to several trillion dollars. The use of concrete surface treatments with waterproofing materials to prevent the access of aggressive substances is an important way of enhancing concrete durability. The most common surface treatments use polymeric resins based on epoxy, silicone (siloxane), acrylics, polyurethanes or polymethacrylate. However, epoxy resins have low resistance to ultraviolet radiation while polyurethanes are sensitive to high alkalinity environments. Geopolymers constitute a group of materials with high resistance to chemical attack that could also be used for coating of concrete infrastructures exposed to harsh chemical environments. This article presents results of an experimental investigation on the resistance to chemical attack (by sulfuric and nitric acid) of several materials: OPC concrete, high performance concrete (HPC), epoxy resin, acrylic painting and a fly ash based geopolymeric mortar. Three types of acids, each with high concentrations of 10%, 20% and 30%, were used to simulate long term degradation by chemical attack. The results show that the epoxy resin had the best resistance to chemical attack, irrespective of the acid type and acid concentration

Caractérisation de l'ensilage des déchets de poisson utilisé comme ingrédient pour l'alimentation de rats

Les déchets de poisson ensilés ont été préparés par addition de Lactobacillus plantarum comme inoculum et de la mélasse (20%) comme source de carbone. Le produit d’ensilage est un liquide contenant 11,02% de protéines brutes, 5,7% de lipides et 7,71% de cendres. Il a été ajouté à la farine d’orge à différentes proportions (30, 40, 50 et 70%) et a été testé contre un aliment commercial pour établir le produit ensilé pouvant donner la meilleure croissance. Le gain de poids et la mortalité ont été suivis pendant 31 jours. Le poids des animaux a augmenté et le test de consommation a montré l’avantage d’inclusion de 30% d’ensilage du poisson dans l’alimentation des animaux traités. L’acceptabilité de l’ensilage du poisson comme ingrédient dans l’alimentation des animaux de laboratoire constitue une alternative pour l’alimentation commerciale

Shrinkage and mechanical performance of geopolymeric mortars based on calcined Tunisian clay

Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry. Since the majority of the existent infrastructures are Portland cement concrete based this means that concrete infrastructure rehabilitation is a hot issue to be dealt with. Geopolymers are novel inorganic binders with high potential to replace Portland cement based ones. Geopolymerization is a complex chemical process evolving various aluminosilicate oxides with silicates under highly alkaline conditions, yielding polymeric units, similar to those of an aluminosilicate glass. So far very few studies in the geopolymer field have addressed the rehabilitation of deteriorated concrete structures. This paper discloses some results of an investigation concerning the development geopolymeric repair mortars based on a calcined Tunisian clay. The results show that Tunisian calcined clay based mortars have hydration products with typical geopolymeric phases. Results also show that the geopolymeric mortar shows a high unrestrained shrinkage behavior and that its modulus of elasticity is below the threshold required for this repair mortars

Mechanical performance of geopolymeric mortars based on tunisian calcined clay, fly ash and metakaolin

Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry. Since the majority of the existent infrastructures are Portland cement concrete based this means that concrete infrastructure rehabilitation is a hot issue to be dealt with. Geopolymers are novel inorganic binders with high potential to replace Portland cement based ones. So far very few studies in the geopolymer field have addressed the rehabilitation of deteriorated concrete structures. This paper discloses results of an investigation concerning the development geopolymeric repair mortars. The mortars are based on Tunisian clay coming from Medenine region, plus calcium hydroxide, sodium silicate and sodium hydroxide. Results show that the geopolymeric mortar has a high compressive strength and a lower unrestrained shrinkage performance as long as partial replacement by metakaolin is carried out. The results also show that Tunisian calcined clay based mortars have hydration products with typical geopolymeric phases

Cost efficiency and resistance to chemical attack of a fly ash geopolymeric mortar versus epoxy resin and acrylic paint coatings

This article presents results of an experimental investigation on the resistance to chemical attack (with sulphuric, hydrochloric and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting and a fly ash-based geopolymeric mortar). Three types of acids with three high concentrations (10, 20 and 30%) were used to simulate long-term degradation. A cost analysis was also performed. The results show that the epoxy resin has the best resistance to chemical attack independently of the acid type and the acid concentration. However, the cost analysis shows that the epoxy resin-based solution is the least cost-efficient solution being 70% above the cost efficiency of the fly ash-based geopolymeric mortar

Shrinkage and mechanical performance of geopolymeric mortars based on calcined Tunisian clay

"Special Issue for International Congress on Materials & Structural Stability, Rabat, Morocco, 27-30 November 2013"Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry. Since the majority of the existent infrastructures are Portland cement concrete based this means that concrete infrastructure rehabilitation is a hot issue to be dealt with. Geopolymers are novel inorganic binders with high potential to replace Portland cement based ones. Geopolymerization is a complex chemical process evolving various aluminosilicate oxides with silicates under highly alkaline conditions, yielding polymeric units, similar to those of an aluminosilicate glass. So far very few studies in the geopolymer field have addressed the rehabilitation of deteriorated concrete structures. This paper discloses some results of an investigation concerning the development geopolymeric repair mortars based on a calcined Tunisian clay. The results show that Tunisian calcined clay based mortars have hydration products with typical geopolymeric phases. Results also show that the geopolymeric mortar shows a high unrestrained shrinkage behavior and that its modulus of elasticity is below the threshold required for this repair mortar

From conformal embeddings to quantum symmetries: an exceptional SU(4) example

We briefly discuss several algebraic tools that are used to describe the quantum symmetries of Boundary Conformal Field Theories on a torus. The starting point is a fusion category, together with an action on another category described by a quantum graph. For known examples, the corresponding modular invariant partition function, which is sometimes associated with a conformal embedding, provides enough information to recover the whole structure. We illustrate these notions with the example of the conformal embedding of SU(4) at level 4 into Spin(15) at level 1, leading to the exceptional quantum graph E4(SU(4)).Comment: 22 pages, 3 color figures. Version 2: We changed the color of figures (ps files) in such a way that they are still understood when converted to gray levels. Version 3: Several references have been adde