asphaltene instability is one of the major problems in gas injection projects throughout the world. numerous models have been developed to predict asphaltene precipitation; the scaling equation is an attractive tool because of its simplicity and not involving complex properties of asphaltene. in this work, a new scaling model is presented to account  for asphaltene precipitation due to gas inje...

introduction: corrosion and scaling of water in distribution systems in spite of imposing economic and aesthetic problems can lead to adverse effects on consumers' health. the present study was conducted to evaluate the corrosion and scaling of water distribution system of sarableh city (ilam, iran) during summer and winter seasons in 2014. materials and methods: totally, 60 samples of wat...

background & aims of the study: corrosion and scaling play undesirable effects on transmission and distribution system of drinking water. the aim of this study was to assess the corrosion and scaling potential of drinking water resources in babol city, iran. materials and methods: totally, 54 water samples were collected from 27 wells in spring and autumn. calcium hardness, ph, total alkalinity...

Periodic composite ultrasonic transducers offer many advantages but the periodic pillar architecture can give rise to unwanted modes of vibration which interfere with the piston like motion of the fundamental thickness mode. In this paper, viscoelastic loss is incorporated into a three-dimensional plane wave expansion model (PWE) of these transducers. A comparison with experimental and finite e...

The optimization problem of ultrasonic testing instrument is studied in this paper. Using ultrasonic nondestructive testing technology to detect quality of products or parts, because the function of conventional ultrasonic testing instruments is custom-built and defined by manufacturers, it is very difficult to meet ever-changing testing requirements such as testing accuracy, testing efficiency...

HIFU power measurement At ultrasonic laboratory of INRIM (Istituto Nazionale di Ricerca Metrologica) it is possible to measure the ultrasonic power emitted by HIFU (High Intesity Focused Ultrasound) transducers. Two different measuring systems for the determination of ultrasonic power have been developed. Both systems are based on the radiation force balance method. The first system is based on...

PURPOSE The effects of magnetostrictive and piezoelectric devices on tooth surfaces seem to differ with regard to the root surface roughness they produce. This study aimed to compare the results of scaling using magnetostrictive and piezoelectric devices on extracted teeth. METHODS Forty-four human extracted teeth were assigned to four study groups (n=11). In two groups (C100 and C200), the t...

The spectrum matching and correlation characteristic are both important in the multiple-user ultrasonic ranging system. As people know, an ultrasonic ranging system, which has a bell-shaped magnitude spectrum, acts like a band-pass filter. If the spectrum of the excitation signal does not match that of the ultrasonic ranging system, some of energy cannot be transmitted by the ultrasonic system....

Ultrasonic energy is used for applying severe plastic deformation on metal surfaces. In the present work, the effect of ultrasonic vibration on the formability, microhardness and microstructural proper...

Current literature supports the use of powered instrumentation over traditional hand instrumentation. The objective of scaling and root planing is the complete removal of plaque and calculus from root surfaces. While this is unrealistic, the accepted end-point is a smooth, glassy root surface during periodontal instrumentation. This often has resulted in overinstrumentation and excessive remova...