res

                if(($ts_new_start >= $ts_obs_start) && ($ts_new_end <= $ts_obs_end)) //3
                    $volno = false;
                if(($ts_new_start < $ts_obs_start) && ($ts_new_end < $ts_obs_end) && ($ts_new_end > $ts_obs_start)) //1
                    $volno = false;
                if(($ts_new_start > $ts_obs_start) && ($ts_new_end > $ts_obs_end) && ($ts_new_start <= $ts_obs_end)) //2
                    $volno = false;
                if(($ts_new_start <= $ts_obs_start) && ($ts_new_end >= $ts_obs_end))  //4
                    $volno = false;