T2* can be considered an observed or effective T2, whereas the first T2 can be considered the natural or true T2 of the tissue being imaged. T2* is always less than or equal to T2. T2* results principally from inhomogeneities in the main magnetic field.These inhomogeneities may be the result of intrinsic defects in the magnet itself or from susceptibility-induced field distortions produced by the tissue or other materials placed within the field.2* can be considered an observed or effective T2, whereas the first T2 can be considered the natural or true T2 of the tissue being imaged. T2* is always less than or equal to T2. T2* results principally from inhomogeneities in the main magnetic field.
The average electricity consumption of a US family of four is in the neighborhood of 50 kWh per day, or 1,500 kWh per month. Similar figures apply for Canada. Assuming an average electricity cost of $0.12 per kWh, that translates into about $6 per day for electricity, or $180 per month.
Here is an example of our usage, for the 12 months between 27th May 2008 and 27th May 2009: 8,587 kWh Peak usage. 4,441 kWh Off Peak Usage. This is a total of 13,028 kWhs per year, (35.7 kWh per day) compared to the Australian national average Electricity consumption of 6,570 kWhs per year (18 kWh per day). (This double door unit is rated at 1240kWh per year, but uses about 1600kWh per year after 3 weeks testing). $ 2  195 Computer (in use 16 hours per day) / Printer / Broadband Modem / Telephone. $ 3  45 Home Computer with Printer for normal family use.