Tin, lead and their alloys, due to their low melting temperatures and wide availability, are the most commonly used solder materials. In fact, lead has been used as a soldering metal for water pipes (also made of lead) even in Roman times, hence the scientific name for lead, Plumbum. Mechanical Properties.
hearing impairment - impairment of the sense of hearing. hearing disorder. disability, disablement, handicap, impairment - the condition of being unable to perform as a consequence of physical or mental unfitness; reading disability; hearing impairment. deafness, hearing loss - partial or complete loss of hearing.
Hearing Loss is any degree of impairment of the ability to apprehend sound and can range from mild to severe. A person can lose hearing in one or both ears. 1  aging, 2  a build up of ear wax, 3  damage to the inner ear, 4  ear infections, 5  a ruptured eardrum,