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.
A typical family house might use 10 kWh to 20 kWh per day (300 to 600 kWh per month) when not air conditioning, and perhaps 1200 to 1500 kWh per month (40 to 50 kWh per day) when using the air conditioning.