Mild steel deterioration inhibition in 1.0M and 5.0M tetraoxosulphate (VI) acid using leaf extract of Pterocarpus santaliniodes

The prevention of deterioration of mild steel in 1.0M and 5.0M H2SO4 solution by leaf extracts of Pterocarpus santaliniodes was investigated in this study using gravimetric and gasometric methods. Data obtained from the study revealed that leaf extracts had a maximum inhibition efficiency of 88.70% and 96% for weight loss and gasometric analysis, respectively for 1.0M H2SO4, and an inhibition efficiency of 71.76% and 79.66% for weight loss and gasometric analysis respectively for 5.0M H2SO4. It was observed that the gasometric method gave the optimum protection. The average activation energy was 73.71KJ/mol in 1.0M H2SO4, and 74.41KJ/mol in 5.0M H2SO4. The adsorption of the phytochemicals on the surface of the mild steel were further assessed by the Langmuir and Freundlich isotherms. The extract was found to be good inhibitor for mild steel corrosion in the H2SO4 solutions. The amount of material loss decreased in the in the presence of the extract when compared to the blank acid solution.Keywords: Mild steel, Corrosion inhibition, H2SO4, Pterocarpus santaliniode

Equilibrium and kinetic studies of Cu (II), Cd (II), Pb (II) and Fe (II) adsorption from aqueous solution using cocoa (Theobroma cacao) pod husk

The potentials of cocoa pod husk to adsorb Cu (II), Cd (II), Pb (II) and Fe (II) ions from aqueous solutions was investigated in a batch system. The effects of contact time, initial metal ion concentration and adsorbent dose on the adsorption capacity of the adsorbent were examined. The percent adsorbed increased as initial metal ion concentration, contact time and adsorbent dose was increased until equilibrium was reached. Langmuir isotherm and pseudo-second order models were used to analyse the equilibrium and kinetic experimental data respectively. Equilibrium experimental data of Cu (II), Cd (II), Pb (II) and Fe (II) adsorption onto cocoa pod fitted well to Langmuir model and the kinetic data also fitted well to the pseudo-second order model, as indicated by the correlation coefficients. The maximum sorption capacity (qmax) ranged as 4.16, 4.42, 4.69 and 4.83 mg/g for Fe (II), Cd (II), Cu (II) and Pb (II) respectively. This study demonstrated that the waste cocoa pod could be used as a potential adsorbent for toxic metals such as Cu (II), Cd (II), Pb (II) and Fe (II).Keywords: Adsorption isotherm, Adsorption Kinetic, Cocoa pod, Langmuir isotherm, Pseudo-second order mode

Proof-of-concept study of compartmentalized lung ventilation using system for asymmetric flow regulation (SAFR)

Asymmetrical distribution of acute lung injury in mechanically ventilated patients can result in a heterogeneity of gas distribution between different regions, potentially worsening ventilation-perfusion matching. Furthermore, overdistension of healthier, more compliant lung regions can lead to barotrauma and limit the effect of increased PEEP on lung recruitment. We propose a System for Asymmetric Flow Regulation (SAFR) which, combined with a novel double lumen endobronchial tube (DLT) may offer individualized lung ventilation to the left and right lungs, better matching each lung's mechanics and pathophysiology. In this preclinical experimental model, the performance of SAFR on gas distribution in a two-lung simulation system was tested. Our results indicate that SAFR may be a technically feasible and potentially clinically useful although further research is warranted

Influence de la teneur en ciment sur les propriétés thermomécaniques des blocs d’argile comprimée et stabilisée

Ce travail vise à déterminer la résistance à la compression et la conductivité thermique des blocs à base d’argile comprimée et stabilisée au ciment d’une part et à étudier la variation de ces propriétés en fonction de la teneur en ciment d’autre part. Les mesures réalisées indiquent que la résistance des blocs sans ciment est de 3,7 MPa par « voie sèche » pour une conductivité thermique de 0,91 Wm-1K-1 (déterminée à l’aide d’un fluxmètre). L’incorporation de ciment entraine une variation de ces deux propriétés. Ainsi on note d’abord une baisse de la résistance suivie d’une augmentation au delà de 4% de ciment. Toutefois la conductivité thermique des blocs ayant les teneurs en ciment les plus importantes reste proche de celle des blocs sans ciment.Mots-clés: bloc d’argile, ciment portland, stabilisation, résistance en compression, conductivité thermique. Influence of cement content on the thermomechanical properties of compressed and stabilized clay blocks This work aims to determine the compressive strength and the thermal conductivity of clay compressed blocks and stabilized with cement and to study the influence of the cement ratio on these characteristics of the blocks. The resistance of blocks without cement is (determined at dry state) is 3.7 MPa and measurements made with a fluxmeter show that the thermal conductivity of these blocks is 0,91 Wm-1 K-1. The results show also that the thermal conductivity and the compressive strength of the blocks vary according to the cement ratio. However the thermal conductivity of the blocks with high cement ratio is close to that of the blocks without cement.Keywords: clay blocks, Portland cement, stabilization, compressive strength, thermal conductivity

FORMULATION OF CONCRETE BASED ON PLANT MATERIALS (CASE OF RICINODENDRON HEUDELOTII: AKPI): OPTIMIZATION OF THE PROPORTION OF SHELLS

The aims of this work is to study the influence of the partial substitution of natural aggregates by the nut shells of Ricinodendron heudelotii known as AKPI, on the physical-mechanical properties of concrete. The substitution rates made are 5%, 10% and 15%. Test results indicate that the presence of Akpi nut shells (ANS) causes increased porosity and reduced compressive strength of concrete. Increasing of porosity and decreasing of strength become important when the quantity of shell increases in concrete. However, the kinetics of hardening at a young age of the concrete is improved from 1% to 7%

Effet de l’addition de fibres de coco traitées à la potasse sur les propriétés mécaniques des matériaux de construction à base d’argile – ciment

Clay is a raw material commonly used for the construction of building materials, thanks to the different stabilization techniques used. These claybased materials have very improved properties when they contain potashtreated vegetable fillers. Thus, coconut fibers, agricultural waste from wad treatment, coconut palm fruit wrap (Cocos nucifra) and treated with a potassium hydroxide solution were used for making clay materials and stabilized with cement. Its objective is to study the influence of these fibers on the properties of the material. To achieve this objective, mortars composed of clays stabilized with 8 % cement and fibers at different levels (0.2, 0.4, 0.6 and 0.8%) for a constant length of 30 mm, been developed. These different mortars with those containing no fibers were subjected to flexural and compression tests. The results obtained show that the addition of fibers improves the mechanical performance of clay mortars stabilized with 8% cement. Especially when these fibers are treated with solution of potash. The treatment of coconut fibers with the traditional potash solution made it possible to increase the maximum stress of the fiber mortar by 13% and by 5% their stiffness compared with untreated fibers. The fiber-matrix adhesion becomes stronger with fiber treatment by 8% by weight of potash

FORMULATION OF CONCRETE BASED ON PLANT MATERIALS (CASE OF RICINODENDRON HEUDELOTII: AKPI): OPTIMIZATION OF THE PROPORTION OF SHELLS

The aims of this work is to study the influence of the partial substitution of natural aggregates by the nut shells of Ricinodendron heudelotii known as AKPI, on the physical-mechanical properties of concrete. The substitution rates made are 5%, 10% and 15%. Test results indicate that the presence of Akpi nut shells (ANS) causes increased porosity and reduced compressive strength of concrete. Increasing of porosity and decreasing of strength become important when the quantity of shell increases in concrete. However, the kinetics of hardening at a young age of the concrete is improved from 1% to 7%

EXPERIMENTAL ANALYSIS OF THE MECHANICAL BEHAVIOR OF CLAY-CEMENT BLOCKS REINFORCED WITH COCONUT FIBERS

This article aims for analyzing under an axial stress, the behavior of earth blocks reinforced by various proportions of coconut fibers. For this fact, compressive and flexural tests were carried out after 28 days of maturation, on dry blocks elaborate with clay stabilized at 8% of cement and containing 0 to 1% of fibers 30 mm length. The experimental results show that the incorporation of fibers in the blocks improves their mechanical characteristics, increases their ductile deformation and delays their cracking. The best mechanical resistances are obtained at 0.8% of fibers because at this content, the distance between fibers is optimal

Application De L’ultrason A L’étude De L’homogénéité Des Briques Réfractaires

The quality of refractory bricks such as their ability to resist to thermal shocks essentially depends on the homogeneity of their structure. The imperfections observed in the structure of some refractory bricks arise from the mode of their preparation. Thus, the homogeneity of bricks manually elaborated with refractory clays and sintered at 1280°C was studied. The speed of ultrasounds in different areas of the bricks was measured with an ultrasound auscultation device. The results point out the speeds of ultrasounds may vary from one zone to another revealing heterogeneities into some bricks. This technique allows showing the distribution of possible heterogeneities in these materials