Qualifying Child. To be considered a qualifying child, your grandchild must be under the age of 19 on the last day of the tax year, or if he's a full-time student, under the age of 24.No age restrictions apply, however, if your grandchild is permanently and totally disabled.ualifying Child. To be considered a qualifying child, your grandchild must be under the age of 19 on the last day of the tax year, or if he's a full-time student, under the age of 24.
Platinum-iridium alloy. Platinum-iridium alloys are alloys of the platinum group precious metals platinum and iridium. Typical alloy proportions are 90:10 or 70:30 (Pt:Ir). These have the chemical stability of platinum, but increased hardness. The Vickers hardness of pure platinum is 56 HV while platinum with 50% of iridium can reach over 500 HV.
Chemical. Platinum is used in fertilizers and explosives as a gauze for the catalytic conversion of ammonia to nitric acid. It is also used in the fabrication of silicones for the aerospace, automotive and construction sector.latinum also has 31 synthetic isotopes ranging in atomic mass from 166 to 202, making the total number of known isotopes 37. The least stable of these is 166 Pt with a half-life of 300 Âµs, while the most stable is 193 Pt with a half-life of 50 years.