A foreign object or food item can be aspirated (sucked into) the airway and can cause obstruction and noisy breathing. Floppy tissues in the respiratory tract can cause noisy breathing due to the collapse of these tissues into the airway.
Sand is a loose, fragmented, naturally-occurring material consisting of very small particles of decomposed rocks, corals, or shells. Sand is used to provide bulk, strength, and other properties to construction materials like asphalt and concrete. It is also used as a decorative material in landscaping. Specific types of sand are used in the manufacture of glass and as a molding material for metal casting. Other sand is used as an abrasive in sandblasting and to make sandpaper. Sand was used as early as 6000 B.C. to grind and polish stones to make sharpened tools and other objects.
Resin sand is a promising new type of modeling material, and at present, it is mainly used in the manufacture of complex sand cores. Since different sands have different advantages, in metal casting, we should adopt the right one to meet different needs.reen Sand (Clay Sand) Clay sand is the mixture of natural silica sand, clay, additives and water. The clay used to make wet clay sand is bentonite clay. The compressive strength is generally 0.05 to 0.1 Mpa.