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.
Sensory impairment is often regarded from a medical/disability point of view and its effects on mental health can be poorly recognised. Communication is a key issue for deaf and deafâblind people and difficulties here underlie developmental, psychological and emotional problems and delay or prevent appropriate assessment and treatment.