"the first and second stage" is correct and usable in written English.
You can use this phrase to describe two distinct parts of a process. For example: "The first and second stage of the launch process were successfully completed."
Several design configurations were suggested for the membrane module arrangements in the first and second stage of the PRO process.
The relevant diffusion and viscous relaxation processes were studied separately by kinetic analysis of the first and second stage of two-stage sorption curves, respectively.
The taxi movement problem is formulated into a two-stage model that consists of two sub-models, namely the first and second stage sub-models.
To achieve this we derive the sample and sample-complement distributions and the moments of the first and second stage measurements.
The RCOG classification system of CTG trace is widely used for the analysis of the fetal heart rate during the first and second stage of labor.
The finite element analysis in the first and second stage was carried out using commercially available finite element software called LUSAS.
We think that the tantalum screw could be indicated only in the first-and-second stage FHN, involving not more than 30% of the joint surface, indeed it shows to provide a mechanical support for the joint surface and favor post-necrotic repair processes, at the same time not ruling out a late prosthesis in case of failure (Fig. 2).
Loss probabilities at the first and second stages are calculated.
An increase in temperature accelerates moisture absorption in both the first and second stages.
CO2 conversion and LPG selectivity were mainly dominated by the first and second stages, respectively.
Permeates obtained from the first and second stages were analyzed using an extraction procedure followed by gas chromatography.
