A small water disinfection system based on the combination of a strong single 25 mW LED with a wavelength of 285 nm and a short quartz tube with an outer rectangular cross section is presented. For the disinfection tests clear tap water and slightly turbid and yellow pond water are contaminated with high concentrations of Escherichia coli bacteria. These water samples are exposed to the germici...

Internal pipeline corrosion in oil production and transportation is always associated with the presence of water, and the likelihood of corrosion generally increases with the volume fraction of water. When the walls of the pipeline are wetted with oil no corrosion is possible. Highly turbulent flow was associated with negligible corrosion due to water entrainment by the flowing oil, whereas low...

Previous research has shown that local scour at bridge piers is severely increased by the accumulation of woody debris around piers. However, due to unavailability accurate information regarding characteristics formed jams, shape and dimensions accumulations tested in previous laboratory experiments have had be assumed. This article provides an assessment debris-induced based on recently availa...

This qualitative study followed the development of 94 pre-service teachers’ assessment perceptions in an introductory course on student assessment. Analysis students’ retrospective and end identified five dimensions. Considerable shifts were detected each dimension: from summative to formative assessment, negative positive perceptions, perceiving as a simple concept complex multifaceted one, hi...

Local scour around bridge piers and abutments is one of the most significant causes failure. Despite a plethora studies on individual or abutments, few have focused joint impact pier an abutment in proximity to another scour. This study conducted laboratory experiments flow analyses examine interaction their effect clear-water The were rectangular flume. They included 18 main tests (with combin...

block ramps are hydraulic structures which are commonly used in river restoration projects. especially in the last few decades, the use of this type of structures have become more and more popular. they furnish a correct balance between the hydraulic functioning and the environmental care, as they minimize the impact on the environment in which they are located. in addition, they can be conside...

phytoplankton and zooplankton concentrations in pishin reservoir are predicted employing a three-dimensional numerical model in this paper. modeling is performed using a numerical model based on mass transport equation. advection, diffusion and source/sink processes are considered as separate subroutines for predicting the concentrations of phytoplankton and zooplankton in the reservoir. finite...

Riverside embayment is expected to provide good habitat for fish in rivers. We measured flow field and water qualities at the artificial embayment zone in the experimental river of the Aquatic Restoration Research Center in order to investigate the mechanism of water exchange in riverside embayment. In a high water stage, flow structures near the embayment were revealed by the measurement. Vege...

abstract bottom intake is one of the most appropriate systems for diverting discharge in steep rivers. bottom intake with porous media is a new system of diverting discharge which can be replaced by bottom rack intakes. to investigate the hydraulic flow characteristics on diverted discharge of this intake, an experimental model was designed in which the inflow, diverted discharge and remained f...