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.
Platinum is found uncombined in alluvial deposits. Most commercially produced platinum comes from South Africa, from the mineral cooperite (platinum sulfide). Some platinum is prepared as a by-product of copper and nickel refining.latinum is used in the chemicals industry as a catalyst for the production of nitric acid, silicone and benzene. It is also used as a catalyst to improve the efficiency of fuel cells. The electronics industry uses platinum for computer hard disks and thermocouples.