Strengthening, repair

Cosmetics are preparations (except so and detergents) for the preservation and beauty of the body. In the rich countries domesticated animals also have their cosmetics, such as creams based on a>3-polyunsaturated fetty acids, for strengthening and repair of feet and noses of hounds and pointers. 

Active anticorrosive pigments inhibit one or both of the two electrochemical partial reactions. The protective action is located at the interface between the substrate and the primer. Water that has diffused into the binder dissolves soluble anticorrosive components (e.g., phosphate, borate, or organic anions) out of the pigments and transports them to the metal surface where they react and stop corrosion. The oxide film already present on the iron is thereby strengthened and sometimes chemically modified. Any damaged areas are repaired with the aid of the active substance. Inhibition by formation of a protective film is the most important mode of action of the commoner anticorrosive pigments. 

So what might we expect in the future Ideally we should try and make tooth enamel impervious to stains. One product that might soon become available is a chewing gum which contains both calcium and phosphate to help teeth to repair cavities by boosting the natural level of these components in our saliva, part of whose job is to repair teeth -see box. However, the best agent for strengthening teeth is still fluoride. 

Granular refractories (castables, mouldables, mortars, etc.) serve for the construction of monolithic kiln and furnace linings, for hot and cold repairs, as mortars for the joining of bricks, etc. Essentially, they are mixtures of refractory granular materials with inorganic binders which provide strengthening in situ . 

The strengthening work necessary at Tunnel Quarry consisted of the repair of existing pillars and the provision of further permanent works to ensure that the overhead cover was adequately supported. It was considered at the time that the roof was so sound and the overhead cover so deep that there was no danger of it breaking up imder bombing attack, but there was some doubt that it was sufficiently supported as a mass. Colonel Minnis noted to the War Office Tunnel Quarry Committee that ... 

REPAIR AND STRENGTHENING OF REINFORCED CONCRETE STRUCTURES BY EPOXY-RUBBER COATINGS [10-25]... 

Not only does meditation heighten attention and quiet the fight-or-flight response, but there is compelling evidence that it may actually help repair a damaged brain and strengthen the immune system. 

The term conventional repair is used in this book to indicate a repair work made on a damaged reinforced concrete structure, which is aimed at restoring protection to the reinforcement by means of replacement of non-protective concrete with a suitable cementitious material. The durability of the repair work is due to the achievement and maintenance of passivity on the reinforcement by the contact with the protective repair material. The repair work can be divided in the following steps a) assessment of the condition of the structure b) removal of concrete in well-defined parts of the structure and for specific depths c) cleaning of the exposed rebars d) application of a suitable repair material to provide an adequate cover to the reinforcement [1-6]. Each of these steps must be carried out properly in order to guarantee the effectiveness of the whole repair work. Additional protection measures can be used to increase the durability of the repair, but they must not interfere with the protection provided by the alkahnity of the repair material. Strengthening may also be required to restore the structural safety of the structure. 

Even if the principal cause of corrosion is carbonation or chloride penetration, construction defects (voids, honeycombs, early cracks, etc.) or other processes of deterioration (sulfate, freeze-thaw, dynamic loading, etc.) can contribute to the damage of the structure. These should be detected in order to take appropriate measures in the repair work. Furthermore, the condition of the structure with regard to stability must be investigated in order to define if strengthening is required. 

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