By examining the insulator firing nose colour, an experienced engine tuner can determine a great deal about the engine's overall operating condition. In general, a light tan/gray colour tells that the spark plug is operating at optimum temperature and that the engine is in good condition. Dark coloring, such as heavy black wet or dry deposits can indicate an overly-rich condition, too cold a heat range spark plug, a possible vacuum leak, low compression, overly retarded timing or too large a plug gap.

Corrosion cells are created on metal surfaces in contact with an electrolyte because of energy differences between the metal and the electrolyte. Different area on the metal surface could also have different potentials with respect to the electrolyte. These variations could be due to i) metallurgical factors, i.e., differences in their composition, microstructure, fabrication, and field installations, and ii) environmental factors. Carbon and low alloy steels are the most widely used material in the oilfield. Stainless steels (Fe-Cr-Ni), and nickel-base corrosion resistant alloys (CRA), such as Incoloys (Ni-Fe-Cr), Inconels (Ni-Cr), Hastelloys (Ni-Cr-Mo-Fe-Co) etc., are also used in highly corrosive environments.

Both crevice corrosion and pitting corrosion can be explained by differential concentration cells, Cathodic reactions, i. e. oxygen reduction or hydrogen evolution may start in the crevice or the pits. Large surface areas will become cathodic and pits or crevices will become anodic and corrode. Metal dissolution will thus be concentrated in small areas and will proceed at much higher rates than with uniform corrosion. Large crevices are less likely to corrode because water movement causes mixing and replenishes oxygen, hydrogen ions, bicarbonate or hydrogen sulfide.

During the initial stages of designing an Integrity Management Program, a key activity carried out, is to identify the degradation mechanisms that are possible in the facility. It is fundamental to understand the relevant mechanisms, their likelihood of occurring in the facility, and the impact that they may have on the facility.

Copper and copper alloy metal surfaces have an intrinsic ability to inhibit the growth of algae, fungi/molds, viruses and bacteria. Studies confirm that these surfaces are effective antimicrobial agents that kill microbes within hours.

Copper has been recognised as a hygienic material since the dawn of civilisation and, in the last two centuries, the anecdotal evidence has been supported by scientific research showing that copper is antimicrobial. Copper inhibits the growth of harmful pathogens - bacteria, moulds, algae, fungi and viruses, so it is antimicrobial.

If your home is over twenty years old, a 98% probability exists that your attic has excessive heat, an indication of unsatisfactory roof ventilation, allowing build-up of excessive attic moisture. Why is excessive attic moisture a problem? Excessive attic moisture leads to more serious problems, including delamination of the roof sheathing, wood rot of structural members, failure of the insulation, leading to higher air conditioning and heating bills, blistering and peeling paint, both interior and exterior, and the development of mold growth, causing serious health problems, disguised as asthma, allergies, colds and sinus conditions. And, in snow climates, excessive attic heat causes ice damming, leading to serious interior water leakage and subsequent damage, often blamed on the roofer, but who is seldom to blame.

Many complaints resulting from roofers using aluminum base flashings and covering with copper counter flashings, which is sold as a Copper Flashing, and the aluminum wears and deteriorates quickly; mixed metals in the fasteners where galvanized nails are used to fasten cooper roofing cleats. Some newcomers to the trade scoff at what is a basic physics lesson in metals usage. 

Aluminum has excellent corrosion resistance property. Its usage as one of the primary metals of commerce to the barrier oxide film that is bonded strongly to its surface and, that if damaged, re-forms immediately in most environments. On a surface freshly abraded and then exposed to air, the barrier oxide film is only 1 nm thick but is highly effective in protecting the aluminum from corrosion.

Microorganisms are found throughout an oil production system, from the deep subsurface of the reservoir rock to the production hardware of pipelines and extraction apparatus above ground. The problems associated with their presence are equally diverse yet can often be considered together. Members of the sulphate reducing bacteria (SRB) are responsible for the majority of the bacterial nuisance in oil production and their presence and growth in a system will often result in a combination of problems.

Corrosion
Technically, corrosion is the destruction of a metal surface by electrochemical reaction with its environment. As soon as your products are exposed to oxygen and humidity, corrosion becomes a negative economic factor which adversely affects not only your production, but also your turnover and business results. So you see that it is worth giving careful consideration to correct corrosion protection. Particularly when you deal in products that are more susceptible to corrosion due to the length of time they are stored and transported.

Power plants increasingly “cycle” to meet market conditions. That’s especially true of many newer combined cycle plants that were designed for continuous operation. Cycling operation creates a host of issues from thermal fatigue failure to freeze protection. Preservation of boilers and heat recovery steam generators (HRSGs) during shutdown and cycling operation generates much discussion. Since most of these plants were designed for base-load and continuous operation, their designs don’t include the equipment one might include for a plant designed for cycling operation.

“Concrete sewer structures and pipes are corroded by sulphuric acid which destroys the cement binder and ultimately results in corrosion of the reinforcing steel. Sulphuric acid is produced in sewers by a complex chain of microbiological and gas/liquid solubility stages which occur as the sewage travels through the sewerage system. These bacteria can create levels of sulphuric acid concentrations as high as 7%. This acid diffuses into the concrete structure, destroys the cement gel binder, and forming soft and soluble gypsum (calcium sulphate hydrate)”.