1 XL â or EXL, Exploration Licence (United Kingdom), a type of onshore licence issued between the First Onshore Licensing Round (1986) and the Sixth (1992). 2  Xln â Crystalline (minerals). 3  XLPE-Cross-linked Polyethylene. 4  XMAC â Cross-Multipole Array Acoustic log.
When the frequency approaches 120 CPM (2 Hz), occupants perceive the ride as harsh. Consequently, the suspension of the average family sedan will have a natural frequency of about 60 to 90 CPM. A high-performance sports car will have a stiffer suspension with a natural frequency of about 120 to 150 CPM (2 to 2.5 Hz). Originally, human sensitivity to ride frequency was believed to be associated with the natural oscillations of an adult human body during a walking gait.
How important is the mileage on a used car? Mileage is probably the single most important factor in determining the value of a used car. The normal mileage for a used car is about 12,000 miles for each year of its life. In other words, a five-year-old vehicle should have about 60,000 miles on its odometer.In locales where people do a lot of driving, such as Southern California, this mileage allotment is increased to 15,000 miles per year.) So when looking for a used car, try to find a vehicle with the least amount of miles you can.