An atom of titanium, with the symbol Ti, represents an element found in the periodic table. Titanium, with atomic number 22, is known for its strength, low density, and resistance to corrosion. It has an electron configuration of [Ar] 3d2 4s2, which is pivotal in its chemical behavior and bonding characteristics. Notably used in aerospace, medical implants, and even in pigments (as titanium dioxide), titanium's versatile properties stem from its atomic structure. It readily reacts with oxygen, forming a passive oxide layer that protects it from further corrosion. Given its abundance in the Earth's crust, it's essential in various industries, yet its extraction process, particularly from ilmenite and rutile ores, underlines the balance between utility and environmental impact.

The correct spelling for the long, continuous length of interlocked fibers that is used in knitting, weaving, crocheting, and sewing is "yarn." Originating from the Old English word "gearn," yarn has been a fundamental component in textile production for centuries. Its use spans a vast array of applications, from crafting beautiful garments and cozy home textiles to industrial uses in manufacturing. The diversity in yarn types, including wool, cotton, acrylic, and blends, caters to various preferences and purposes, making it a versatile material in both hobbyist and professional textile arts. Understanding different yarn weights and their appropriate uses can significantly enhance the outcome of a textile project.

Polypropylene (PP), a thermoplastic polymer, exhibits specific flammability characteristics important for safety and application considerations. Its flammability limits pertain to the concentrations of its vapors in air that could ignite if exposed to an ignition source. Generally, PP has a relatively high ignition temperature around 570°F (300°C), indicating it requires substantial heat to combust. However, its exact flammability limits can vary depending on factors such as the presence of additives, the form (e.g., fibers, film, or bulk), and processing conditions. Understanding these limits is crucial for manufacturers and users to implement appropriate safety measures, especially in environments where high temperatures are prevalent or in applications where fire resistance is critical. Adjusting the material formulation with flame retardants or applying surface treatments can enhance PP's fire resistance, making it safer for a broader range of applications.