n class="p">(</span><span class="n">C_PI</span><span class="o">*</span><span class="n">dr</span><span class="o">**</span><span class="mi">2</span><span class="o">/</span><span class="mi">4</span><span class="p">)</span>
       <span class="k">else</span>
<span class="k">          </span><span class="n">Vden</span><span class="p">(</span><span class="n">ii</span><span class="p">)</span><span class="o">=</span><span class="n">Vpart</span><span class="p">(</span><span class="n">ii</span><span class="p">)</span