Musical instruments that start with the letter I include the igil, ipu, Irish uillean, Irish bouzouki, ichigenkin, inci, iya, itotele and istarski mih. The instruments originate from countries ranging from Cuba and Ireland to Croatia, Japan and the Philippines.
Bessel's functions are often used in acoustics for describing circular membranes behaviour (exploited by most of the musical instruments). They are the solutions of the wave equations using polar coordinates. Set the properties of the membrane Bessel's functions describe the vibrational modes of the membrane.
Mussels are molluscs with two hinged shells (bivalves) which filter their food from the surrounding water. Mussels can be found attached to gravel, seawall, and rocks in intertidal and subtidal coastal areas. healthy mussel whose shell is open should close when gently tapped. If the shell is broken or the meat is dry, the mussel should be discarded. Beard, clumps of dark threads attached to the shells, are normal and are used to anchor mussels to rocks and other materials.