�?�?t ε l ρ l v l + �?�?ε l ρ l v l v l = ε l �?�?τ l + ε l ρ l g �?ε l �?p �?β v l �?v s Take note: Drillopedia.com is often a submission-based understanding-sharing web-site. Contributors post information primarily based on their knowledge and expertise. Buyers really should use their discretion when employing