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.
There are 4 platinum alloys commonly used in the USA. 1  Pt900/Ir = 900 parts platinum, 100 parts Iridium. 2  Pt950/Ir = 950 parts platinum, 50 parts Iridium. 3  Pt950/Ru = 950 parts platinum, 50 parts Ruthenium.  Pt950/Co = 950 parts platinum, 50 parts Cobalt.