Galvanization is the process of coating iron or steel with a layer of zinc to protect it from corrosion.

Corrosion can be prevented by selecting materials with high corrosion resistance in the service environment—e.g., choosing stainless steel, suitable alloys (Ni/Cr-based) or non-metals and coatings resistant to the electrolyte. Design measures include using proper material thickness, avoiding crevices and stagnant zones (which promote pitting/crevice corrosion), ensuring good joint design (gasket/bonding) and smooth surfaces, and providing cathodic protection where needed. Also, selecting compatible metals to avoid galvanic corrosion and maintaining correct heat-treatment and protective film formation help reduce corrosion.

Van Arkel method is a physical-chemical process used to purify titanium. Impure titanium (usually in the form of Ti metal) is heated in a closed vessel with iodine (I2). Titanium reacts with iodine to form volatile titanium iodide (TiI4), which carries the impurities away. The formed TiI4 vapour then decomposes on a heated filament/zone (at higher temperature) to deposit pure titanium metal and release iodine again. Thus, the purified titanium is collected and iodine is recycled, enabling high-purity titanium production.

Proximate analysis of coal is important because it determines the main constituents—moisture, volatile matter, ash, and fixed carbon—which helps in assessing coal quality and suitability for different uses. The results allow prediction of calorific value, combustion behavior, and efficiency of burning, and they also indicate the amount of non-combustible ash and the expected extent of residue formation.

Lubricants reduce friction and wear, form a protective film to prevent corrosion, and help dissipate heat.

Concentration of ore means removing unwanted gangue (impurities) from the ore so that the percentage of the desired metal/mineral increases. Any ore beneficiation/ concentration is based on differences in physical or chemical properties between the ore mineral and the gangue. Discussed below are four common methods.

Gravity concentration (washing/sluicing/jigging)This method uses the difference in density between ore particles and gangue.

Magnetic separationThis method is based on difference in magnetic properties of ore and gangue.

Froth floatation (concentration by selective wetting)This method is used mainly for finely divided ores where gravity or magnetic methods are less effective.

Leaching (chemical concentration)Leaching uses chemical action to dissolve the valuable metal/mineral selectively, leaving gangue behind.

Conclusion: Concentration methods are chosen based on the nature of ore and gangue. Gravity and magnetic methods are mainly physical, froth floatation is based on surface chemistry and hydrophobicity, and leaching is based on selective chemical dissolution.

Flash point is the lowest temperature at which a lubricant gives off enough vapour to ignite briefly; fire point is the temperature at which it continues to burn for at least a short time after ignition.

Composite materials are materials made by combining two or more distinct constituents (typically a matrix and a reinforcement) to obtain properties that are better than those of the individual components. Example: Fiberglass (glass fibres embedded in a polymer matrix) is a composite material.

Addition polymerization is a process in which unsaturated monomers (usually having C=C double bonds) add to each other directly to form a polymer chain without formation of any by-product (e.g., polythene from ethene). Condensation polymerization is a process in which two different monomers (or a monomer with two reactive groups) combine with elimination of a small molecule such as H₂O or HCl to form the polymer (e.g., nylon-6,6 from hexamethylenediamine and adipic acid).