The type of fit between a mating shaft of diameter $25.0^{\begin{matrix} +0.010 \\\ -0.010 \end{matrix}}$ mm and a hole of diameter $25.0^{\begin{matrix} +0.015 \\\ -0.015 \end{matrix}}$ is ______.

Which of the following methods can improve the fatigue strength of a circular mild steel (MS) shaft?

A bracket is attached to a vertical column by means of two identical rivets U and V separated by a distance of 2a = 100 mm, as shown in the figure. The permissible shear stress of the rivet material is 50 MPa. If a load P = 10 kN is applied at an eccentricity e = 3√7 a, the minimum cross-sectional area of each of the rivets to avoid failure is ___________ mm².

Which of the following heat treatment processes is/are used for surface hardening of steels?