Sudden pipe expansions have been known as efficient hydraulic energy dissipaters for a long time. The complex phenomenon of flow separation and velocity discontinuity at the interface of incoming jet and the recirculation flow, results in intensive shear and tensile rupture of the fluid and the associated destructive phenomenon of cavitation. This paper focuses on aeration in sudden pipe expansion as a remedy to recover the effects of cavitation. The experimental setup consists of a sudden pipe expansion with an expansion to inflow diameter ratio of 3.675. Variation of air content ratio with respect to the Reynolds number and effect of air entrainment on time averaged velocity and pressure distribution is investigated. Finally a combination of sudden pipe expansion and aeration is recommended for energy dissipation at bottom outlets and tunnel spillways.

Advanced Oxidation Processes (AOPs) are the effective processes in treatment of the various wastewaters contaminated with hazardous organic pollutants. In this work, decolorization of Acid Blue 74 in the UV/H2O2 process by using a batch photochemical reactor equipped with a 15 W low pressure mercury lamp (Osram) and aeration system as stirrer was studied. At the short time decolorization was complete and follows first order kinetic with respect of dye concentration. The rate of decolorization at the maximum absorption wavelength was monitored with spectrophotometric analysis. Effect of the important parameters such as initial concentration of H2O2, pH and initial concentration of dye on the dye decolorization was studied. It was found that the rate of decolorization increase with increase in H2O2 concentration up to 0.0294 mole.L-¹. The great rate of decolorization observed at the pH=3. With increasing the initial concentration of the dye up to 6.43×10-5 M, initial reaction rate was increased.

Introduction: The aim of this study is evaluation of efficacy of lacrimal sac localization with lacrimal probe without using light pipe. The study was based on nonrandomized prospective clinical trial with one year follow up period.Methods: A group of 40 patients operated since march 2001 to December 2004 The operation was Endoscopic Dacryocystorhynostomy and localization of lacrimal sac, which was performed with a lacrimal probe inserted in lacrimal sac. With pushing the probe inferomedialy pierces lacrimal sac lacrimal bone, and nasal musca over the bone. Follow up includes symptom evaluation such as epiphora and endoscopy. Success was defined as relief of symptoms & duct patancy with irrigation for a 1 year period.Results: 29 patients were male (72.5 %) and 11 were female (27.5 %). Mean age was 37.5 (with SD±12.26) in 20 patients right eye involved, left eye involved in 16 cases and in 4 cases both eyes involved. For 3 patients septoplasty was done besides EDCR. success rate was 82.5% and no complication was seen.Discussion: the use of lacrimal probe for lacrimal sac localization is a safe and easy method and don't have light pipe limitations then can replace light pipe.

To divert water from a large diameter irrigation pipeline to a smaller diameter plastic gated pipe so called "Hydroflume", a pipe turnout was designed and built in the Sugar cane development and Byproducts Company with the cooperation of the Shahid Chamran University, Ahwaz, Iran. This pipe turnout not only conveys water but it also dissipates the excess energy. The structure has of a circular broad crested weir for measuring flow discharge. It also was equipped by a piezometer to facilate flow measurement. The turnout consists of two 800-millimeters precast concrete pipe and has been designed in such a way that can be produced in large quantities in the factory and then installed in the farm. In this paper the design criteria including: investigation of various alternatives and selection of the best type, hydraulics and structural design, laboratory and field tests are presented.