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.
Standard protocol in the US dictates that the tassel be worn on the right side of one's mortarboard at commencement and then, during the ceremony, moved to the left side. Teachers and administrators at commencement place their tassels on the left. It symbolizes one's transition from candidate to graduate.