The use of pumps linked in parallel or series in large scale pipe systems is usually inevitable, to meet the required head and discharge. Transient flow occurs following a pump failure in a pump group as a result of variations in the flow rate. This research is an investigation about waterhammer caused by one or more pump-switch off in a pump group when they are connected in parallel. The opera...

Introduction: In radiation therapy, determining the location of the tumor accurately during irradiation is one of the most important requirements. However, lung tumors are not fixed in a single location and move during irradiation due to respiratory motion. Due to limitations in assessing such movements, using a lung phantom can be useful and operational for their fast, easy an...

INTRODUCTION Apical debris extrusion (DE) subsequent to root canal instrumentation, is one of the most important causes of endodontic flare-ups. The aim of this study was to compare the amount of DE after root canal instrumentation using nickel-titanium (NiTi) hand files with step-back manual technique or installed on reciprocating handpiece. METHODS AND MATERIALS This study was conducted on ...

In this study we sought to determine whether characteristics of ventricular-induced atrial preexcitation during reciprocating tachycardia could help differentiate atrioventricular (AV) nodal reentry from orthodromic AV reentry using an accessory pathway and to identify the site of accessory pathways in patients with Wolff-Parkinson-White syndrome. Fifty-five patients with orthodromic AV recipro...

The objective of the present study was to assess the effectiveness of reciprocating instrumentation in disinfecting oval-shaped root canals infected with Enterococcus faecalis. Forty-five human lower premolars were infected with a culture of E. faecalis (ATCC 29212) for 28 days. Five other teeth that were neither contaminated nor instrumented were used as controls. The 45 specimens were divided...

An advanced warning system for maintenance and control of reciprocating compressors is discussed. The compressor is instrumented to measure valve temperatures, interstage pressures and temperatures, rod drops, packing temperature and leakage flow, and numerous other variables. Under control of a microcomputer, a scanner monitors the sensors and updates a database. After a scan, an expert progra...