Titanium is the ninth most abundant element in the Earth's crust, constituting about 0.6% of its mass. This makes it more common than elements like copper and zinc. Titanium is never found in its pure form in nature; it's always bonded with other elements, mainly in minerals such as ilmenite and rutile. Despite its abundance, the process to extract and refine titanium metal is complex and costly, which affects its availability and price on the market. The metal's excellent strength-to-weight ratio, corrosion resistance, and biocompatibility make it highly valuable for aerospace, medical implants, and high-performance sports equipment. Its widespread use in various industries is limited by the difficulty and cost of extraction and refinement, but research into more efficient production methods could increase its accessibility.

Injection molding and blow molding are popular methods used for manufacturing plastic products, each serving distinct purposes. Injection molding is highly versatile for making a wide variety of parts with intricate designs and tight tolerances. It involves injecting molten plastic into a mold cavity where it cools and solidifies. This method is ideal for high-volume production of items such as automotive components, toys, and electronic housings. Blow molding, on the other hand, is primarily used for producing hollow plastic products such as bottles, containers, and other packaging materials. It involves extruding a tube of molten plastic, which is then enclosed in a mold. Air is blown into the tube, expanding it to the shape of the mold. Blow molding is favored for its ability to produce lightweight, cost-effective containers with uniform wall thickness. Choosing between the two methods depends on the specific requirements of the product, including shape, volume, and material characteristics.

To measure the diameter of a PVC pipe accurately, one needs to know whether to find its outer or inner diameter since PVC pipe sizes are typically based on the nominal pipe size (NPS) system which references the inner diameter (ID). For the outer diameter (OD), use a caliper or a flexible measuring tape to wrap around the pipe, then divide the measurement by π (approximately 3.14) to find the diameter. Ensure the pipe is accessible from all sides for an accurate measurement. For the inner diameter, it's more straightforward if you have the specifications or can check the manufacturer's details. If not, measure the outer diameter and subtract twice the wall thickness, which you can measure with a caliper at the pipe's end. Accurate measurement is crucial for fitting compatibility and ensuring proper flow characteristics within the piping system.