Thorough purging of all four bearing seals on each universal joint can help alleviate the possibility of mixing incompatible greases. U-joint cross, broken at a bearing surface. U-joints seldom break off at the bearing surface. It takes a very large shock load to cause this type of failure. It is also very difficult to inspect for this type of failure because they, many times, start as a small crack and progress into a complete failure some time further âdown the roadâ.
A quantity called the slew rate, which is the rate of change of gradient amplitude is usually quoted in evaluating gradient performance and potential physiological effects (e.g. a maximum slew rate of 200 Tm-1s-1).
Skewness of a random variable that have zero variance and zero third central moment. If I have a random variable $x$, and the only information I know about it are: $$ m_1=E[x]=c, \mu_2=var(x)=0, \mu_3=E[(x-m_1)^3]=0$$ Can I conclude that the function distribution is symmetric about c? Symmetric distributions have skewness = 0, and the definition of skewness in wikipedia is: $$ \gamma = \frac{\mu_3}{\sigma^3}$$.