A PHP Error was encountered

Severity: Warning

Message: fopen(files/publish/published-pdf-118-6-5.Natural Convection with Surface Radiation in Vertical Channels with Multiple Heat Sources.pdf): failed to open stream: No such file or directory

Filename: controllers/announce.php

Line Number: 599

A PHP Error was encountered

Severity: Warning

Message: fclose() expects parameter 1 to be resource, boolean given

Filename: controllers/announce.php

Line Number: 619